5.3.2. Closure Objectives and Criteria

EKATI MINE ICRP August 2018

2018 Ekati Mine Interim Closure and Reclamation Plan Version 3.0 123

5.3.2. Closure Objectives and Criteria

While the use and function of each pit is unique, the ultimate closure state for the open pits is for them to be flooded and become pit lakes that are connected to the local watershed via connector and outflow channels once the water quality in the pit lakes has met closure water quality criteria. The overall closure approach for the open pits has been developed through a number of reports and studies and associated engagement and feedback, beginning with the original EAs, part of ICRP Version 2.4 (BHP Billiton 2011a), and annual closure and reclamation progress reports.

Based on the closure goals and principles for the Ekati mine ICRP, six closure objectives were identified specifically for the closure and reclamation of the open pits. The objectives and criteria of the ICRP relating specifically to reclamation of open pits are presented in Table 5.3-2. The specificity of some closure criteria (e.g., quantitative metrics) will be expanded on during future revisions of the ICRP or in the final closure plan, based on the outcomes of reclamation research and future updates to modelling studies.

Table 5.3-2 Closure Objectives and Criteria for Open Pits

ID Objective Action Criteria Measurement/Monitoring

OP-1 Pit lake water quality is acceptable for entry into the Receiving Environment.

Flood pit to meet minimum freshwater coverage depth over PK or to maintain meromixis. Reconnect pits to Receiving Environment once closure water quality criteria is met.

Surface water quality complies with closure water quality criteria.

Water quality monitoring during and post-flooding

OP-2 There are no significant impacts to source lake aquatic habitats during pit flooding.

Develop and follow pit flooding plan, taking into account potential impact on aquatic environment.

Flooding is completed in accordance with the approved flooding plan. Water levels in source lakes are maintained within acceptable limits, as outlined in the pit flooding plan.

Routine monitoring during pit flooding

OP-3 Littoral zones are provided in selected pit lakes.

Design and build littoral zones in selected pit lakes.

Build is per WLWB-approved design.

As-built drawings (construction meets design specifications)

OP-4 Fish passage connectivity is established in pit lake outflow and connector channels in pit lakes where littoral zones are built.

Design and build outflow and connector channels. Establish fish passage once open-pit closure water quality criteria have been achieved.

Build is per WLWB-approved design. Physical configuration of outflow and connector channels permits fish passage.

Physical inspection by qualified professional

OP-5 Outflow and connector channels on site are stable to a degree that is consistent with natural channel stability.

Design and build channels to avoid erosion in excess of natural systems.

Channels are built in accordance with design, with no significant slumping, subsidence, or erosion occurring during the post-closure monitoring period.

Physical inspection by a qualified professional

OP-6 Safe egress from pit lakes is provided for wildlife and humans.

Back-flood pits. Leave pit ramps in place for pit egress. Place littoral zones in selected pit lakes

Pit ramps are left per approved design (i.e., pits back-flooded and pit ramps left intact). Littoral zone is built per WLWB-approved criteria.

Physical inspection by a qualified professional to confirm completion in accordance with approved design

PK = processed kimberlite; WLWB = Wek'èezhı̀ı Land and Water Board.



5.3.3. Community Engagement

Dominion has engaged with the TKEG and community groups on the topics of littoral zones and wildlife safety related to the pit lakes through a number of means, including TKEG meetings; workshops held in Yellowknife, and community visits (Appendix C). In particular, during the 27–28 February 2018 workshop in Yellowknife, a specific portion of the agenda was focused on littoral zones. Dominion representatives presented some of the background related to what littoral zones are and why they may be part of pit lake design. Preliminary ideas of how littoral zones would be addressed in ICRP Version 3.0 were presented, and Dominion sought to hear feedback on these ideas and to answer questions. In particular, the concept was presented that each pit lake will have unique characteristics that must be evaluated, and that littoral zones may not be the appropriate solution for each pit lake. Dominion planned to undertake a pit-by-pit evaluation, considering aspects such as water quantity and quality, ecological complexity, constructability, and economics which would help to guide decision making related to the final design for each pit.

Feedback from the 27–28 February 2018 workshop regarding open-pit closure focused on pit lake littoral zones and water quality parameters in pit lakes, the source of water for flooding, the potential for downstream impacts to the larger watershed, and the general process of how pit flooding will be carried out. Specific questions regarding the suitability of water and fish for consumption upon pit flooding, the potential for pit lake overflow, and the duration of water quality monitoring were raised. Dominion addressed questions and concerns by providing details on how and when pit flooding activities will occur. While limited specific recommendations were received during the workshop, there was general agreement that each pit should be evaluated individually and that communities should be involved in monitoring opportunities and reclamation studies. Following from the workshop, feedback was incorporated and the evaluation of littoral zones was advanced, as presented in Section 5.3.4.1. Similar concerns were echoed in the 2018 community visits, with feedback on the ICRP Version 3.0 open-pit closure and reclamation approach centred on source water, water quality and fish habitat, and ongoing monitoring. Of particular concern was the potential for residual PK to influence in-pit and ground water quality.

5.3.4. Consideration of Options and Selection of Closure Activities

The overall closure approach for the open pits has been developed and established through a number of reports and studies, beginning with the original EAs, as part of ICRP Version 2.4 (BHP Billiton 2011a), and through annual closure and reclamation progress reports. In particular, past work has identified and assessed the most appropriate source lakes and pumping rates. These are no longer carried forward as options, but have been embedded within the base closure plan. One key area where options evaluation is ongoing is related to establishing littoral zones in pit lakes. Decisions related to littoral zone design are also closely linked to fish passage connectivity and channel stability. The current state of evaluation related to littoral zones is outlined below.

5.3.4.1. Littoral Zones in Pit Lakes

The pit lake environment that is planned as the final landscape for the open pits is acknowledged to be different than a natural lake environment. In particular, these pit lakes will be lacking some of the key components of a natural system that support the ecological complexity required for an aquatic environment, including:

• small upstream catchment area, which causes

o intermittent outflow that may be limited to the freshet period, or may not flow at all in dry years

o limited upstream supply of sediments and nutrients (especially for pits where WRSAs represent a large portion of the upstream catchment)

• steep-sided banks and deep lake bottom, which cause

o low habitat diversity and limited areas that can be biologically productive



o high potential for loss of sediment/nutrients to the deep lake bottom (no potential for wind mixing and redistribution of bottom sediments)

To help address these limitations, and increase the ecological complexity of the pit lake environment, reclamation of the open pits includes consideration of the construction of littoral (shallow-water) zones in areas of selected pits to facilitate the development of aquatic ecosystems in the pit lake. The topographic and environmental conditions within and surrounding each open pit are unique, and some pits will have a higher likelihood of success than others in terms of evolving into a functional aquatic ecosystem that supports fish. Littoral zones are not planned around the entire perimeter of a selected pit; for example, littoral zones cannot be constructed in areas that would introduce physical stability and safety risks associated with adjacent WRSAs or unstable ground. Also, it should be noted that the steep-sided bank features that would remain present a likely positive net effect for species such as raptors and waterfowl.

Figure 5.3-1 illustrates the conceptual design for a littoral zone within an area of a pit lake perimeter. Design considerations for the littoral zones may include substrate, with the outer rim of the littoral areas protected by rock berms to reduce loss of substrate into the deep basin. Aquatic plants and riparian vegetation may be used to stabilize erodible substrate material and to contribute organic inputs that may support the potential for aquatic use of the pit lake.

Figure 5.3-1 Conceptual Pit Lake Littoral Zone



The overall reclamation commitment is to engage with DFO prior to submitting designs to the WLWB for approval and then to build the approved design. To facilitate engagement with DFO and all stakeholders, Table 5.3-3 to Table 5.3-9 provide a summary of the key variables that are taken into consideration when developing pit-specific littoral zone designs, as well as pit-by-pit commentary. Table 5.3-10 then summarizes the key considerations for each pit and evaluates candidates for further design and planning of constructed littoral zones. For Jay, the open pit itself will be fully submerged within Lac du Sauvage, and therefore, no specific littoral zone design is required. After the dike is breached, areas located between the dike and the open pit will return to their pre-development water depth, and areas that previously provided littoral habitat will be expected to re-establish as littoral habitat. The dike itself will provide some areas of new littoral habitat.



Table 5.3-3 Pigeon Pit – Littoral Zone Design Considerations

Water Quantity and Quality

Prior to development, Pigeon Stream flowed from an upstream catchment area (630 ha) containing several small and medium-sized lakes to Pigeon Pond, then downstream to Fay Bay of Upper Exeter Lake. The PSD now diverts the flow from this catchment area around Pigeon Pit.

In the current closure plan, PSD, which was created under a Fisheries Act Authorization, will remain in place into post-closure (i.e., permanent); thus, Pigeon Pit Lake will be a headwater pit lake, with a very small catchment area (111 ha). As a result of the small catchment area, outflow from the Pigeon Pit Lake is anticipated to be intermittent. The outflow will pass through a short constructed channel to lower Pigeon Stream.

The pit lake will be 169 m deep and 735 m in diameter. Water to flood Pigeon Pit will be pumped from Upper Exeter Lake. There is a low likelihood for meromixis due to low salinity.

There is a relatively high percentage of metasediments in the pit wall lithology, which, if exposed to the atmosphere for an extended period, represents a risk of ARD/ML. To mitigate this risk, Dominion plans to flood Pigeon Pit as part of progressive reclamation (rather than waiting until final closure).

Depending on observed pit lake water quality, there may be future consideration of the potential to improve long-term water quality by routing Pigeon Stream through the pit lake (i.e., close and reclaim the PSD). The increased runoff that would flow through the pit lake from the upstream catchment area could result in lower constituent concentrations in the pit lake. However, in trade-off, this would result in loss of the current aquatic habitat that has been established within the PSD.

Constructability

If selected for littoral zone construction, further work would be required to review pit rim topography and pit wall stability to identify target areas for littoral zones and areas where exposed pit wall will remain. This will be completed as part of final littoral zone design to be reviewed with DFO prior to submission to the WLWB. Key aspects of design would include:

- defining technical constraints for scaling back pit walls to create littoral zones (e.g., stability criteria, equipment and access requirements)

- consideration of glacial till that forms portions of the upper Pigeon Pit walls - consideration of ARD/ML potential of exposing new areas of metasediments - focusing on establishing littoral zones in areas with adjacent natural tundra as a source of sediment and

nutrients, and considering exposure to wind, precipitation, sunlight - focusing on areas adjacent to connector channel(s) - avoiding areas adjacent to WRSAs - incorporating emergency egress for caribou and other wildlife

Ecological Complexity

Natural fish populations are present in downstream Pigeon Stream and Fay Bay of Upper Exeter Lake that could provide populations for colonization of Pigeon Pit Lake. The short distance of the connector channel provides high confidence that connectivity could be established to the pit lake. However, the intermittent outflow could be a limiting factor for fish movement outside the freshet period. Note that prior to mining, Pigeon Pond was a small and shallow waterbody that froze to bottom in winter and, therefore, did not provide overwintering habitat for fish. Overwintering habitat is not considered limiting in this system.

Depending on observed water quality, there is the potential opportunity to improve long-term water quality and overall ecological complexity by redirecting the PSD through the pit lake. A larger upstream catchment area could result in lower water quality constituent concentrations, and increased supply of sediments and detritus to support ecosystem functioning. However, in trade-off, this would result in loss of the current fish habitat that has been established within the PSD. Also, the physical shape of the pit lake represents a risk that those inputs would be lost to the deep unused area of the pit lake such that those ecologically valuable materials are effectively removed altogether from the lower Pigeon/Fay/Exeter system. It is, therefore, unclear whether routing Pigeon Stream though Pigeon Pit Lake would be of ecological benefit to the Pigeon/Fay/Exeter system.

Business Considerations

Given that Pigeon Pit is planned to be flooded during mine operations (i.e., progressive reclamation), littoral zone and outflow channel construction could also be completed during mine operations. This would make use of operational personnel, equipment, and support networks to conduct the work efficiently and would lead to reduction in financial security.

However, Pigeon Pit Lake cannot be connected to Pigeon Stream until such time that acceptable long-term water quality has been demonstrated, and connection to the stream has, therefore, been approved by the WLWB. It is unclear how long the post-flooding period will require; a nominal 10-year timeframe is currently proposed. Therefore, it is unlikely that Pigeon Pit Lake could be connected to Pigeon Stream during mine operations.

Detailed cost evaluation would be completed as part of final design.

Pigeon Pit is located relatively close to main site infrastructure, such that availability of materials and hauling distances may be shorter than for other pits.

PSD = Pigeon Stream Diversion; ARD/ML = acid rock drainage / metal leaching; DFO = Fisheries and Oceans Canada; WLWB = Wek'èezhı̀ı Land and Water Board; WRSA = waste rock storage area.



Table 5.3-4 Beartooth Pit – Littoral Zone Design Considerations


Beartooth Pit is located within the drainage flow between Bearclaw Lake and Upper Panda Lake. At closure, following flooding of Beartooth Pit, Bearclaw Lake will be reconnected to Beartooth Pit Lake, forming a mid-watershed pit lake. Beartooth Pit will overflow to Upper Panda Lake and then flow downstream to Kodiak Lake via the PDC.

Flow to Beartooth Pit Lake will be re-established from Bearclaw Lake by breaching the Bearclaw Dam and reconstructing an inflow stream. The outflow into Upper Panda Lake will also be re-established by construction of a connection to the existing natural Beartooth Lake outlet channel.

The pit lake is anticipated to be in the range of 30 to 100 m in depth (depending on the amount of FPK settlement in the pit) and 490 m in diameter. Water to flood Beartooth Pit will be pumped from Upper Exeter Lake. Over the long term, water quality risks are expected to be low, as there is a large upstream catchment (260 ha) that would contribute runoff annually, with a relatively small percentage contribution (8%) of runoff being derived from the closed WRSAs and pit walls.

Constructability

If selected for littoral zone construction, further work would be required to review pit rim topography and pit wall stability to identify target areas for littoral zones and areas where exposed pit wall will remain. This will be completed as part of final design to be reviewed with DFO prior to submission to the WLWB. Key aspects of design would include:

- defining technical constraints for scaling back pit walls to create littoral zones (e.g., stability criteria; equipment and access requirements)

- focusing on establishing littoral zones in areas with adjacent natural tundra as a source of sediment and nutrients; considering exposure to wind, precipitation, sunlight

- focusing on areas adjacent to connector channel(s) - avoiding areas adjacent to WRSAs - incorporating emergency egress for caribou and other wildlife


Beartooth Pit is the only open pit that would naturally form a mid-watershed pit lake. It has higher likelihood of being ecologically viable because the inflow from Bearclaw Lake will provide upstream lake source of aquatic plants (seeds) and invertebrate drift for recolonization of littoral and riparian zone. Also, the shallower depth due to PK deposition reduces the likelihood that sediments/nutrients would be lost to the deep unused area of the pit lake.

Undisturbed tundra to the north and east of the pit perimeter may contribute to natural colonization of littoral zone by plants.

Natural fish populations for recolonization are present in adjacent lakes in the watershed (Bearclaw and Upper Panda lakes); however, fish passage would rely on design and construction of connector channels from Bearclaw Lake and to Upper Panda Lake that allow passage.



Beartooth Pit is located near main site infrastructure, such that availability of materials and hauling distances may be shorter than for other pits.

Beartooth Pit is currently planned to be used as a PKCA and water management facility throughout the remaining mine life. Construction of littoral zones would not occur until final closure activities.

PDC = Panda Diversion Channel; WRSA = waste rock storage area; FPK = fine processed kimberlite; DFO = Fisheries and Oceans Canada; WLWB = Wek'èezhı̀ı Land and Water Board; PKCA = processed kimberlite containment area.



Table 5.3-5 Fox Pit – Littoral Zone Design Considerations


The pre-development discharge from Fox Lake was to the southwest under what is now the Fox WRSA, toward a series of smaller lakes (i.e., Fox 2 and 3). After flooding at closure, Fox Pit Lake will flow, via a new flow path and engineered connector channel, to One Hump Lake.

Fox Pit Lake will act as a headwater pit lake where the resulting catchment area (estimated as 192 ha) will include an estimated 80% reclaimed WRSA.

The pit will have diameter of 890 m and a maximum depth of 332 m.

Water to flood Fox Pit will be pumped from the LLCF. Fox Pit flooding is scheduled to take place over 18.5 years, starting in 2021 and ending in 2039, with passive pit flooding occurring since 2014. Water quality modelling indicates that Fox Pit Lake has a moderate likelihood for meromixis.

Constructability



- focusing on establishing littoral zones in areas with adjacent natural tundra as a source of sediment and nutrients; considering exposure to wind, precipitation, sunlight (limited availability at Fox Pit)



Opportunity for generating ecological complexity is lower than for other pit lakes.

The WRSA located around the majority of the pit lake will not contribute to natural colonization by plants or invertebrates.

At 332 m maximum depth, only a small portion (approximately 5%) of Fox Pit Lake depth will be within the euphotic zone, reducing biological productive capacity.

There is no natural pre-development outflow channel. Fish passage, if required, would rely on design and construction of a relatively long connector channel to One Hump Lake that allows passage.


Detailed cost evaluation would be completed as part of final design. Flooding is scheduled to occur over a long period of time, with littoral zones only becoming flooded and active well into the post-closure period (2039).

Where possible, work to scale back pit rim and construct littoral zones is to be scheduled/optimized with other activities related to closure of the Fox WRSA.

WRSA = waste rock storage area; LLCF = Long Lake Containment Facility; DFO = Fisheries and Oceans Canada; WLWB = Wek'èezhı̀ı Land and Water Board.



Table 5.3-6 Sable Pit – Littoral Zone Design Considerations


The pre-development flow from Sable Lake was north into Ulu Lake; however, at closure, this drainage path will be covered by the Sable WRSA. After Sable Pit has been flooded at closure, Sable Pit Lake will act as a headwater pit lake with a small catchment area around the pit rim. Discharge will be to the west to the Two-Rock Sedimentation Pond. Outflow to the Two-Rock Sedimentation Pond will be established through construction of a connector channel.

No PK fill is planned to be placed in Sable Pit Lake at closure; the pit will have a maximum depth of 278 m. Pit walls are dominated by relatively unreactive rock (i.e., granite, diabase, and kimberlite).

Water to flood Sable Pit will be pumped from Ursula Lake. Sable Pit flooding is scheduled to take place over 13 years, starting in 2027 and ending in 2039. Sable Pit Lake is predicted to have a low likelihood for meromixis due to low salinity.

Constructability



- focusing on establishing littoral zones in areas with adjacent natural tundra as a source of sediment and nutrients; considering exposure to wind, precipitation, sunlight (limited area to the southeast at Sable Pit)



Opportunity for generating ecological complexity is lower than for other pit lakes.

Sable Pit Lake will have a very small catchment area with limited natural tundra to contribute to natural colonization by plants or invertebrates.

At 278 m maximum depth, only a small portion of Sable Pit Lake depth will be within the euphotic zone, reducing biological productive capacity.

The likelihood of successful fish colonization is lower for Sable Pit Lake than other pit lakes. There is no natural pre-development outflow channel. Fish passage would rely on design and construction of a connector channel to the reclaimed Two-Rock Sedimentation Pond that allows passage. Recolonization of Sable Pit Lake by fish will require passage of fish through the Two-Rock Sedimentation Pond from downstream Horseshoe Lake.



Flooding is scheduled to occur over a long period of time, with littoral zones only becoming flooded and active well into the post-closure period (2039).

Where possible, work to scale back pit rim and construct littoral zones is to be scheduled/optimized with other activities related to closure of the Sable WRSA.

Sable Pit is located relatively far from main site infrastructure, such that material availability and hauling distances would be costlier than for other pits.

WRSA = waste rock storage area; PK = processed kimberlite; DFO = Fisheries and Oceans Canada; WLWB = Wek'èezhı̀ı Land and Water Board.



Table 5.3-7 Lynx Pit – Littoral Zone Design Considerations


The pre-development Lynx Lake was a headwater lake with its primary outflow southeast to Lac de Gras. The majority of the flow in the outflow channel was subterranean, through boulder gardens. An ephemeral stream also flowed during periods of high water levels from Lynx Lake's north end to Hammer Lake. Due to the location of the Lynx kimberlite pipe, Lynx Pit is located over only the southwestern portion of Lynx Lake. A small northeastern portion, although drained, remains intact.

Lynx Pit will be used as a settling facility for water with elevated levels of TSS during the second phase of dewatering the Jay diked area (in conjunction with Misery Pit). This water will remain in the pit with natural runoff filling the pit for final closure. Filling with natural net inflows is expected to occur starting in mid-2023 and ending in, or prior to, 2028.

Lynx Pit will have a maximum depth of 120 m; no PK fill is planned to be placed in the pit at closure. Once Lynx Pit Lake is fully flooded, it will act as a headwater pit lake flowing through the natural existing Lynx Lake outlet channel to Lac de Gras.

Constructability






Lynx Pit Lake will have a small catchment area; however, undisturbed tundra along the majority of the pit perimeter may contribute to natural colonization by plants.

Natural fish populations for recolonization are present in downstream Lac de Gras; however, flow in the natural outflow channel to Lac de Gras was historically assessed as primarily subterranean and through boulder gardens which would likely prevent or significantly limit fish passage to Lynx Pit Lake except under high flow conditions. The outflow channel may require modification if fish passage is required as part of the final closure design.

At 120 m maximum depth, only a small portion of Lynx Pit Lake depth will be within the euphotic zone, reducing biological productive capacity.



The flooding schedule for Lynx Pit is relatively short and is expected to be completed by 2028. Therefore, littoral zone and outflow channel construction could potentially be completed during mine operations, making use of operational personnel, equipment, and support networks to conduct the work efficiently, and could lead to reduction in financial security. Where possible, work to scale back pit rim and construct littoral zones is to be scheduled/optimized with other activities related to closure of the Misery Pit and WRSAs.

Lynx Pit is located relatively far from main site infrastructure, such that material availability and hauling distances would be costlier than for other pits.

TSS = total suspended solids; PK = processed kimberlite; DFO = Fisheries and Oceans Canada; WLWB = Wek'èezhı̀ı Land and Water Board; WRSA = waste rock storage area.



Table 5.3-8 Misery Pit – Littoral Zone Design Considerations


The pre-development Misery Lake was a headwater lake with its primary outflow southeast to Lac de Gras.

Following the completion of underground mining activity in Misery Pit, it will be used as a water management facility for minewater from the MUG Project and then for the dewatering and operations stages of Jay Pit mining. Final closure of Misery Pit is scheduled at the end of LOM, and will involve lowering the in-pit water level to approximately 60 m below the final overflow elevation and then creating a 60 m cap of freshwater from Lac du Sauvage.

Misery Pit will have a maximum depth of 145 m, with a mixture of granite and metasediment lithology in the pit walls. Due to the placement of saline minewater at depth, a meromictic lake is predicted to form.

Misery Pit Lake will be a headwater pit lake at closure, with a very small reporting catchment, limited to the pit and the ground adjacent to the pit. Approximately 20% of the catchment area is within the WRSA. Outflow to Lac de Gras will be through re-establishment of a connection to the existing pre-development outflow channel.

Constructability






Misery Pit Lake will have a small catchment area; however, undisturbed tundra along the majority of the pit perimeter may contribute to natural colonization by plants.

Natural fish populations for recolonization are present in downstream Lac de Gras, and the natural channel between Misery Lake and Lac de Gras that historically supported fish passage can be reconnected.

At 145 m maximum depth, only a small portion of Misery Pit Lake depth will be within the euphotic zone, reducing biological productive capacity.



Flooding is not scheduled to occur until after the end of LOM, with littoral zones becoming flooded and active in approximately 2036.

Misery Pit is located relatively far from main site infrastructure, such that material availability and hauling distances for materials would be costlier than for other pits.

Where possible, work to scale back pit rim and construct littoral zones is to be scheduled/optimized with other activities related to closure of the Jay, Misery, and Lynx areas.

MUG = Misery Underground; LOM = life of mine; WRSA = waste rock storage area; DFO = Fisheries and Oceans Canada; WLWB = Wek'èezhı̀ı Land and Water Board.



Table 5.3-9 Panda/Koala/Koala North Pit – Littoral Zone Design Considerations


Prior to development, Panda and Upper Panda lakes were connected as a single lake. Inflow came from Beartooth Lake to the northwest and Polar Lake to the northeast. A short stream connected Panda Lake to Koala Lake downstream, and then to Kodiak Lake. To allow development of the pits, the PDC was constructed under a Fisheries Act Authorization to divert water from Upper Panda Lake to Kodiak Lake.

In the current closure plan, the PDC will remain in place into post-closure (i.e., permanent) and continue to provide fish habitat. As such, the coalesced Panda/Koala Pit Lake will be a headwater pit lake, with a total catchment area of 229 ha, 38% (88 ha) of which is located in the WRSA.

Outflow from the Panda/Koala Pit Lake will be to Kodiak Lake through the construction of a connector channel. An emergency spillway will be constructed around the Panda Dam that will allow safe passage of flood flows from Upper Panda Lake to Panda Pit Lake. This is a precautionary measure to protect against general flooding of the area in a flood event or if the PDC is temporarily blocked with snow during freshet.

PK will be deposited in Panda and Koala pits during mining activities at the Ekati mine. The reclamation plan calls for a 30 m freshwater cap to be placed over the FPK. Water for the freshwater cap will be pumped from Upper Exeter Lake. This will occur at the end of LOM, when mining of Jay Pit is completed.

Long-term water quality of the Panda/Koala Pit Lake is being evaluated through modelling studies. In particular, the potential release of porewater from the PK as it consolidates makes predictions in this pit lake more complex. Depending on predicted water quality as modelling advances over time, there is the potential opportunity to improve long-term water quality by redirecting the PDC through the pit lakes. A larger upstream catchment area could result in lower water quality constituent concentrations, and increased supply of sediments and detritus to support ecosystem functioning. However, in trade-off, this would result in loss of the current fish habitat that has been established within the PDC. With many years of mine life remaining until final closure, this trade-off will continue to be evaluated as water quality modelling of the Panda/Koala Pit Lake is refined over time.

Constructability





Preliminary analysis suggests that the Koala Pit area has higher potential for establishing littoral zones than the Panda Pit area. There is a naturally shallow zone that will develop in the area that floods between Koala and Koala North. Because the Panda and Koala pits will be hydraulically connected their lake level will be equivalent. This will lead to the exposure of higher pit walls in Panda, which would require deeper bench cuts and larger excavation volumes to establish littoral zones.


Undisturbed tundra to the east and northeast may contribute to natural colonization by plants. A large, naturally shallow littoral area would develop in the area that causes the pits to coalesce.

At the initial maximum depth of 30 m, 100% of Koala Pit Lake depth would be within the euphotic zone, contributing to biological productive capacity during the initial establishment period. How much FPK consolidation will occur is an area of ongoing study.

Overflow from Upper Panda Lake through the spillway may provide intermittent upstream lake source of aquatic plants (seeds) and invertebrates for recolonization of littoral and riparian zone.

Natural fish populations for recolonization are present in Upper Panda Lake (intermittent access through spillway), and downstream in Kodiak Lake. However, a natural pre-development outflow channel is not present downstream; therefore, fish passage would rely on design and construction of a connector channel to Koala Pit Lake that allows passage.



Flooding is scheduled to occur at the end of LOM, with littoral zones only becoming flooded and active well into the post-closure period (2039).

Where possible, work to scale back pit rim and construct littoral zones is to be scheduled/optimized with other activities related to closure at the main camp and WRSA.

Panda, Koala, and Koala North pits are located adjacent to main site infrastructure; therefore, material availability and hauling distances for would be less costly than for other pits.

PDC = Panda Diversion Channel; WRSA = waste rock storage area; PK = processed kimberlite; FPK = fine processed kimberlite; LOM = life of mine; DFO = Fisheries and Oceans Canada; WLWB = Wek'èezhı̀ı Land and Water Board.



Table 5.3-10 Preliminary Evaluation of Candidate Open Pits for Constructed Littoral Zones

Open Pit Summary of Key Considerations Preliminary Rating

Panda/Koala/Koala North

Large proportion of headwater catchment is WRSA PK deposition results in shallower lake, reducing risk of loss of sediments/nutrients to lake bottom A large, naturally shallow littoral area would develop in the areas connecting Koala, Koala North, and Panda pits Proximity to main site infrastructure is beneficial for construction

Good candidate for constructed littoral zones; continue planning

Beartooth Only mid-watershed pit; input from upstream catchment increases sediment/nutrient availability PK deposition results in shallower lake, reducing loss of sediments/nutrients to lake bottom Proximity to main site infrastructure is beneficial for construction

Best candidate for constructed littoral zones, continue planning

Fox Large proportion of headwater catchment is WRSA, resulting in primarily nutrient-poor inflows Due to small catchment, pit lake outflow is anticipated to be intermittent; the pit lake is expected to provide poor aquatic habitat with limited ecological complexity, and there is potential for fish to be unable to move out of the pit lake

Low rating—not selected as a candidate for constructed littoral zones

Misery Lack of nutrient-rich inflows and likely loss of nutrients/organics to deep basin Due to small catchment, pit lake outflow is anticipated to be intermittent; the pit lake is expected to provide poor aquatic habitat with limited ecological complexity, and there is potential for fish to be unable to move out of the pit lake Distance from main site infrastructure would increase costs to haul materials relative to other pits


Pigeon Lack of nutrient-rich inflows and likely loss of nutrients/organics to deep basin Due to small catchment, pit lake outflow is anticipated to be intermittent; the pit lake is expected to provide poor aquatic habitat with limited ecological complexity, and there is potential for fish to be unable to move out of the pit lake PSD stream habitat provides greater value than introducing lake habitat Proportion of metasediments introduce potential water quality risks Connector channel allowing fish movement is possible Potential to be constructed as progressive reclamation

Medium rating—not selected as a candidate for constructed littoral zones

Lynx Lack of nutrient-rich inflows and likely loss of nutrients/organics to deep basin Pit lake outflow is anticipated to be intermittent, and natural outflow did not historically allow fish passage. The pit lake is expected to provide poor aquatic habitat with limited ecological complexity, and there is potential for fish to be unable to move out of the pit lake Potential to be constructed as progressive reclamation Distance from main site infrastructure would increase costs to haul materials relative to other pits

Medium rating—not selected as a candidate for constructed littoral zones

Sable Relatively large proportion of headwater catchment is WRSA Lack of nutrient-rich inflows and likely loss of nutrients/organics to deep basin Fish would need to traverse from Horseshoe Lake, through Two-Rock Sedimentation Pond before reaching pit lake Pit lake outflow is anticipated to be intermittent; the pit lake is expected to provide poor aquatic habitat with limited ecological complexity, and there is potential for fish to be unable to move out of the pit lake Distance from main site infrastructure would increase costs to haul materials relative to other pits


WRSA = waste rock storage area; PK = processed kimberlite; PSD = Pigeon Stream Diversion.



5.3.5. Engineering Works Associated with Selected Closure Activity

5.3.5.1. Closure Activities

The following closure activities will be carried out for open pits:

• Remove any remaining infrastructure or equipment within the open pits.

• Deposit PK into Beartooth and Panda/Koala pits (i.e., PK from Jay Operations), leaving space for a 30 m freshwater cap.

• Pump minewater from Jay Pit into Misery Pit during Jay Operations.

• Pump minewater from Misery Pit (top 60 m) to Jay Pit to fill lower pit levels at end of Jay Operations.

• Assess pit wall stability for pit lakes that are required to remain meromictic (Misery and Jay).

• Construct physical measures as necessary to maintain safety and limit access for people and wildlife during pit flooding and post-closure.

• Construct a roadway if necessary for pipeline and access to the pump from the source lake to pit.

• Construct a water pumping system and pipeline.

• Pump water from the source lake until the pit is flooded to the desired in-pit water elevation.

• Construct littoral zones along portions of the pit lake perimeter in selected pits in accordance with the approved design.

• Construct an outflow connector channel from the pit lake to the stream/flowpath to the receiving environment.

• Once the pit flooding program is complete, remove the pumping and piping systems.

• Reclaim the pipeline roadway in the same manner as mine site roads.

Additional details that have been developed regarding the planning for specific closure measures and individual pits are discussed in the following sections.

5.3.5.2. Information Development

The following sections describe the outcomes of specific studies that have been conducted to support closure planning since the last ICRP update.

Pit Lake Water Quality Predictions

A fundamental closure objective for the open pits is that the pit lake water quality inside the open pits is acceptable for the Receiving Environment. This objective will be achieved by ensuring that the pit lake surface water quality complies with final closure water quality criteria prior to reconnecting with the local hydrological system. If required, water within the pits will be managed until it meets the required Water Licence criteria.



To support closure planning, pit lake water quality modelling studies have been completed to predict future water quality. The initial pit lake modelling was reported in ERM Rescan (2013a,b). Subsequently, new/updated modelling to incorporate the Jay and Misery pits was reported in the Jay EA (DDEC 2014a) and Water Licence amendment application (Golder 2016a) and review processes, and the MUG Water Licence amendment application (Golder 2017). Updated modelling to evaluate pit water quality of Panda/Koala/Beartooth with deposited PK was reported in Golder (2018a).

Each of these modelling studies use combined water balance and water quality models to predict water quality based on estimates for each of the inputs. For open pits that will have deposited PK (Panda, Koala North, Koala, and Beartooth) or minewater (Misery and Jay), a key additional consideration is the amount of freshwater that will need to be placed on top of the PK and the minewater to ensure that the closure water quality criteria are achieved. In the absence of defined final closure water quality criteria, water quality benchmarks as defined in the Ekati mine’s Aquatic Response Framework have been used to screen the pit lake closure water quality predictions.

Provided below is an overall summary of the modelling results and their implications for closure to date for the various open pits. Summaries for Fox, Pigeon, and Sable pit lakes are presented initially, followed by open pits that will have deposited PK (Panda, Koala North, Koala, and Beartooth) or minewater (Misery and Jay).

Fox Pit

Key aspects of the Fox Pit Lake water quality model (ERM Rescan 2013b) are as follows:

• Pumped inflow is sourced from LLCF and will take 18 years to fill the pit.

• Runoff from the WRSAs (approximately 2 km2) surrounding Fox Pit will drain to the pit lake at closure, and represent approximately 3% of the inflows.

• Groundwater inflow, which has higher TDS than surface runoff, is expected to make up 3% of the inflows to the pit lake.

• Pit walls are 90% granite, 5% kimberlite, and 5% diabase.

The base case model scenario predicts that water quality parameter concentrations will remain below the water quality benchmarks (ERM Rescan 2013b). The bulk chemistry results presented for Fox Pit Lake filled with LLCF water suggest that TDS concentrations in the pit lake could be 540 to 640 mg/L, which suggests an increased likelihood of meromixis forming in Fox Pit Lake over time. However, the formation of meromixis in a pit lake is an added benefit to the closure condition, but is not critical for achieving closure goals and objectives.

Pigeon Pit

Key aspects of the Pigeon Pit Lake model are as follows:

• Pumped inflow is sourced from Upper Exeter Lake and will take three years to fill the pit.

• The volume of water entering Pigeon Pit Lake from surface runoff is expected to be small (less than 1%) (ERM Rescan 2013a).

• No groundwater inflow is expected; thus, the potential for meromixis is low.

• Pit walls are 50% granite and 50% metasediment. The exposed metasediments have the potential to create acidic runoff and to increase parameter concentrations in the surface water layer.



The base case model run predicts exceedances of benchmarks for cadmium and copper in the early years after the filling of the pit lake. However, over time concentrations of many variables are predicted to increase due to the assumption of constant leach rates from metasediment exposed in the Pigeon Pit wall. By 250 years after the pit has filled, the base case predicts exceedances of water quality benchmarks for sulphate, aluminum, cadmium, copper, iron, nickel, and zinc (ERM Rescan 2013a). Over time, the salinity of Pigeon Pit Lake is also predicted to increase slightly as a result of loadings from exposed pit walls, but this is insufficient to produce meromixis within the pit lake. Pigeon Pit Lake is predicted to mix to the bottom each year (ERM Rescan 2013a).

Since the time that the Pigeon Pit Lake model was originally run, the size of the Pigeon Pit shell has increased (diameter and depth). This increases the volume of water that needs to be pumped from the source lake; however, the fundamental outcome related to the long-term potential impact of pit wall runoff is not materially changed.

Ultimately, due to a small (0.03 to 0.1 km2) watershed draining to the pit lake, the annual outflow volume from the pit lake is very low, trending to zero outside the freshet period. As a result, loading to the downstream environment is considered negligible, even if surface water quality exceeds water quality benchmarks.

Sable Pit

Key aspects of the Sable Pit Lake water quality model are as follows:

• Pumped inflow is sourced from Ursula Lake and will take 13 years to fill the pit.

• Sable Pit has a small local drainage of 0.6 km2 and no stream inflow; therefore, the volume of water entering Sable Pit Lake from surface runoff is expected to be approximately 4% of the total infill volume (ERM Rescan 2013a).

• No groundwater inflow is expected; thus, the potential for meromixis is low.

• Pit walls are dominated by relatively unreactive rock (i.e., 90% granite, 5% diabase, and 5% kimberlite).

For Sable Pit, the model results predict there will be no meromixis within the pit lake, although there will be natural stratification at times of the year in response to air temperature and snow melt. The model results indicate that cadmium is the only water quality variable that is predicted to exceed water quality benchmarks for the base case or any of the scenarios run. Concentrations of all other water quality variables are below water quality benchmarks. Overall, the model predicts that the water quality within the full Sable Pit Lake will be of good quality with low TDS concentrations (ERM Rescan 2013a).

Since the time that the Sable Pit Lake model was originally run, the size of the pit shell has increased (diameter and depth). This increases the volume of water that needs to be pumped from the source lake; however, the fundamental outcome related to the long-term steady state condition is not materially changed.

Panda, Koala North, and Koala Pits

Water quality models for Beartooth, Panda, Koala North, and Koala pits were included in a modelling report (Golder 2018a) with the Ekati Diamond Mine 2017 Closure and Reclamation Progress Report (Dominion 2018e) in January 2018 to evaluate the post-closure pit lake water quality following placement of freshwater caps over the deposited PK in these facilities. Updated water quality models, including the development of hydrodynamic models, for the Panda, Koala North, and Koala Pit Lakes were included in a subsequent report (Golder 2018b) to support PK deposition planning for these pits (i.e., the Panda and Koala Deposition Study as per Part H, Condition 32 of the Water Licence). The objectives of the water quality modelling were as follows:

• Investigate the behaviour of the FPK in each pit lake, once deposited.



• Estimate consolidation of FPK, leading to settlement and porewater release.

• Predict the quality of the resulting supernatant water, in combination with other inflow sources.

Supplemental to any pit closure modelling completed previously for pits where PK deposition is planned, FPK consolidation and porewater release after deposition was accounted for in the closure water quality modelling using estimates from the application of the one-dimensional, large-strain consolidation modelling software CONDES0. The influence of FPK settling on long-term pit lake water quality was then evaluated using GoldSim modelling software. Provided is an overall summary of the closure water quality modelling effort.

• Large-strain consolidation modelling indicates that the FPK will settle up to 110 m in Panda Pit, 90 m in Koala North Pit, and 115 m in Koala Pit at 200 years from the end of deposition. Consolidation will continue beyond 200 years, albeit at declining rates.

• Consolidation of FPK will release porewater into the overlying pit lake as the FPK settles. Water quality models were developed to evaluate the influence of FPK settling on long-term water quality in the pit lakes, which will be connected by a surface channel in post-closure.

• Hydrodynamic modelling, which incorporated a catchment-scale water balance, including the predicted porewater release, indicated that the three modelled pit lakes are expected to be holomictic (i.e., fully mixed at least once per year) over time post-closure.

• Water quality modelling indicated that some constituents, including constituents predominantly sourced from FPK porewater release, remained below benchmarks and either peaked (followed by a decreasing trend) or approached steady-state during the modelled timeframe. This result suggests that these constituents can be considered to not be a long-term concern.

• Constituents sourced from WRSA seepage, exhibited a gradual increasing trend throughout the modelled timeframe; maximum predicted concentrations for four of these constituents (aluminum, copper, chromium, and iron) were greater than benchmarks at some point during the modelled timeframe. This result suggests that this trend is independent of FPK deposition. The source term for WRSA seepage entering the modelled pit lakes is considered to be conservative, in part because of the assumption of constant loadings over time.

• The modelling results relied upon to arrive at these conclusions were based on several conservative assumptions. These assumptions provide a moderate to high level of confidence that, while the precise concentrations predicated are not expected to be realized, the actual concentrations are likely to be lower.

• Monitoring of the inputs to the pit lakes between now and the start of filling, and then during the filling period, will allow Dominion to update models, verify or refine predictions, and adaptively manage the inflows to improve water quality of the supernatant water if necessary.

Beartooth Pit

A water quality modelling report submitted with the Ekati Diamond Mine 2017 Closure and Reclamation Progress Report (Dominion 2018e) in January 2018 evaluated post-closure water quality conditions following placement of freshwater caps over the deposited PK in Beartooth Pit (Golder 2018a). Key aspects of the model for Beartooth Pit are as follows:

• Pumped inflow for a 30 m freshwater cap is sourced from Upper Exeter Lake.

• One year (seasonally) will be needed for pump flooding.



• Following placement of the freshwater cap, Bearclaw Lake, located upstream, will be reconnected to Beartooth Pit. Beartooth Pit Lake will overflow to Upper Panda Lake and then downstream to Kodiak Lake via the PDC.

• The pit wall lithological proportions used to calculate the pit wall runoff water quality were 5% metasediment, 5% diabase, 5% kimberlite, and 85% granite.

For Beartooth Pit, the consolidation modelling indicates that over time, FPK will settle up to 58 m in the centre of the pit. Beartooth Pit Lake water quality evolves to be similar to that of Bearclaw Lake since Bearclaw Lake will be connected to Beartooth Pit Lake at closure. When steady-state concentrations are achieved, process water liberated from FPK consolidation accounts for less than 1% of the total annual inflow to Beartooth Pit Lake. However, some water quality constituents in Beartooth Pit Lake are projected to exceed water quality benchmarks in the long term: phosphorus, total aluminum, copper, and iron. The modelling assumptions were developed for monomictic conditions (annual turnover and mixing). However, based on the amount of consolidation that is predicted, it is reasonable to assume that the pit lake would not fully mix (i.e., meromictic conditions could establish).

Misery Pit

Key aspects of the post-closure water quality modelling for Misery Pit Lake are as follows:

• Misery Pit will become the primary minewater management facility for the Jay Project and contents will also include minewater generated from MUG.

• At closure, the minewater stored in the upper part of Misery Pit will be pumped to the bottom of Jay Pit to create room for a freshwater cap.

• Pumped inflow sourced from Lac du Sauvage and natural surface runoff will be used to create a 60 m freshwater cap, and pumping will take approximately 4.5 months.

• Misery Pit walls are composed of metasediment and granite.

• The stability of meromixis was evaluated through hydrodynamic modelling of the first 200 years after back-flooding, using CE-QUAL-W2 model and mass balance calculations over 5,000 years using a vertical mass-balance slice spreadsheet model.

A key objective of the site water management plan for MUG and Jay Pit is to establish meromictic conditions in the Misery Pit to preclude minewater in the denser, lower layer of the pit (monimolimnion) from mixing with the overlying freshwater in the upper layer of the pit (mixolimnion), and thereby potentially affecting the closure objective for the pit (i.e., the water quality of Misery Pit is safe for use by fish, wildlife, and people). The minewater with elevated TDS is predicted to remain in the lower part of Misery Pit Lake following the creation of the freshwater cap due to density stratification, thereby creating a meromictic lake. This closure strategy has been documented through the Jay EA (DDEC 2014a) and review process and Jay Water Licence Amendment application (Golder 2016a), and most recently in documents to support the MUG Project Water Licence amendment (Golder 2017).



Based on modelling work completed, meromixis is predicted to form and remain stable into post-closure (i.e., 200 years) in Misery Pit. Model results indicate that following back-flooding, TDS and other water quality constituents (e.g., chloride, phosphorus, and nitrate) will slowly increase in the mixolimnion, reaching steady-state conditions as a result of gradual upward diffusion from the monimolimnion over time (Golder 2017). Although some constituents show slight increases relative to closure surface water quality predictions, operational monitoring and adaptive management strategies required under the Water Licence (e.g., freshwater cap optimization studies) provide added confidence that Misery Pit will satisfy closure goals and objectives and not pose an environmental risk. Into the long term (e.g., 5,000 years), natural groundwater migration from Misery Pit reduces TDS in the monimolimnion, producing a well-mixed waterbody that will continue to meet closure goals and objectives.

Using monitoring results obtained during operations, Dominion will conduct an optimization study to evaluate the optimal depth of the freshwater cap required to maintain meromictic conditions and water quality in Misery Pit that is compatible with traditional uses, per Measure 4-2b of the REA (MVEIRB 2016) and Part H, Condition 2c of the amended Ekati mine Water Licence to include the Jay Project (WLWB 2017). However, modelling to date indicates meromictic conditions will form and remain stable with a 60 m freshwater cap (Golder 2016a, 2017). Monitoring will also be conducted during back-flooding and prior to the reconnection of the pit lake to Lac de Gras.

Lynx Pit

The mined-out Lynx Pit (in conjunction with Misery Pit) will be used as a settling facility for total suspended solids (TSS) laden water during the final dewatering phase of the diked area of Lac du Sauvage (Golder 2016a). Approximately 6.2 million m3 of TSS-laden water will be pumped to Lynx Pit, leaving a residual 3 m of freeboard. This freeboard will be allowed to flood via natural net flows, which is estimated to take approximately 5.6 years to fill. The TSS should settle within Lynx Pit Lake during this time, and the resultant Lynx Pit Lake water quality is expected to be similar to Lac de Gras (Golder 2016a). Once the storage capacity of the pit lake is filled, the runoff will overflow through the Lynx Pit Lake outlet to Lac de Gras.

Jay Pit

Key aspects of the post-closure Jay Pit water quality model are as follows:

• At closure, minewater will be transferred from Misery Pit (i.e., consisting of groundwater inflows and other sources of water) to create the lower monimolimnion layer.

• Pumped inflow to fill the upper layer of Jay Pit and the diked area in Lac du Sauvage is sourced from Lac du Sauvage, and will take approximately three years to fill.

• The stability of meromixis in Jay Pit in closure and into the long term was evaluated through hydrodynamic modelling of the first 200 years after back-flooding, using CE-QUAL-W2 model and mass balance calculations over 5,000 years using a vertical mass-balance slice spreadsheet model.

A key objective of the site water management plan for Jay Pit is to establish meromictic conditions to preclude minewater in the denser, lower layer of the pit (monimolimnion) from mixing with the overlying freshwater in the upper layer of the pit (mixolimnion), and thereby potentially affecting the closure objective for Lac du Sauvage (i.e., the water quality of Lac du Sauvage is safe for use by fish, wildlife, and people). The minewater with elevated TDS is predicted to remain in the lower part of Jay Pit following the creation of the freshwater cap due to density stratification. This closure strategy has been documented through the Jay EA (DDEC 2014a) and review process and Jay Water Licence Amendment application (Golder 2016a), and most recently in documents to support the MUG Project Water Licence amendment (Golder 2017).



Based on modelling work completed, meromixis is predicted to form and remain stable into post-closure (i.e., 200 years) in Jay Pit. Into the long-term (e.g., 5,000 years), meromixis in Jay Pit is projected to become stronger. As described above for Misery Pit, Dominion will conduct a freshwater cap optimization study, per Measure 4-2b of the REA and Part H, Condition 2c of the amended Ekati mine Water Licence to include the Jay Project (WLWB 2017).

Source Lake Withdrawal and Pump Flooding Schedule

It would take an exceptionally long time for precipitation alone to flood the pits. To bring the timeframe down to a period that can reasonably achieve closure objectives, and ultimately relinquishment, pumping from a nearby source lake is required. A closure objective associated with the identification of source lakes, and the associated pumping rates/windows, is that there should be no significant adverse effects to the source lake aquatic habitats during pit flooding.

The initial source lake identification and assessment was reported in ICRP Version 2.4 (BHP Billiton 2011a) and Modelling Water Quality and Water Quantity Impact of Infilling Fox Pit Lake with LLCF Water (ERM Rescan 2013b); subsequently, an updated evaluation to incorporate the Jay, Misery, and Lynx pits was reported in Jay EA (DDEC 2014a) and review process. Table 5.3-11 summarizes the source lake and planned pumping rates, and a summary of each source lake is provided below. In general, the source lakes are all large waterbodies with sufficient volume and catchment areas to be able to support withdrawal via pumping. The proposed pumping rates and seasonal constraints have been established to ensure they would not have a significant negative effect on surface elevations of source lakes and downstream lakes and on outlet stream flows.

Table 5.3-11 Source Lakes for Pit Lake Pump Flooding

Source Lake Annual Water Drawn from Source Lake (million m3)

Long Lake Containment Facility 3.5 Limited to open water season

Upper Exeter Lake 5.0 Limited to open water season

Ursula Lake 2.5 Limited to open water season

Lac du Sauvage 31.1 Year-round

Lac de Gras(a) 31.1 Year-round

(a) Lac de Gras will only be required for pump flooding of Lynx Pit if Jay Pit is not developed.

Long Lake Containment Facility

The use of LLCF as source lake for flooding Fox Pit was originally proposed in the 2013 Ekati Diamond Mine: Closure and Reclamation Progress Report (DDEC 2013c). ERM Rescan (2013b) describes potential water quality implications of withdrawal from LLCF, and ERM (2014) presents results of additional 2014 field and modelling studies. These studies show that with a pumping rate of 0.3 m3/s for five months of the year (June to October), and a constant outflow from the LLCF to Leslie Lake was maintained, then the guideline flow conditions at Nero-Nema Stream (which represents the best quality fish habitat compared to other relevant streams) can be maintained.

Approval to use the LLCF as a source lake for flooding Fox Pit Lake at an annual volume of 3,500,000 m3 and an average rate of 0.3 m3/s (during open water season) was provided by the WLWB in November 2014.



Ursula Lake

Ursula Lake is located south of Sable Pit. It is approximately 23.0 km2 in size and is recharged by a catchment area of 94.6 km2 having a maximum relief of approximately 32 m. Waterbodies account for approximately 40% of the catchment area. The lake flows into a channel on its southeast side, which flows through a series of lakes and channels, and ultimately into Lac de Gras.

A stream gauge was installed at the Ursula Lake outflow in 2001. Four years of flow data are available and were used by EBA Engineering Consultants Ltd. (EBA 2006a) to evaluate the effects of pumping.

A pumping rate of 0.2 m3/s or annual water extraction of 2,500,000 m3 results in an approximate 21% reduction in the annual discharge volume at the Ursula Lake outflow (EBA 2006a). At this extraction rate, a minimum downstream flow of 0.4 m3/s will be maintained from June to September. This extraction volume is not anticipated to impact the downstream hydrological regime and was used as an upper bound for planning.

Upper Exeter Lake

Upper Exeter Lake is located west of Pigeon Pit. The lake area is approximately 27.3 km2 in size and is recharged by a catchment area of 228.4 km2, with a maximum relief of approximately 36 m. Waterbodies account for approximately 27% of the catchment area. The outflow of Upper Exeter Lake discharges directly to Exeter Lake.

A pumping rate of 0.4 m3/s or annual water extraction of 5,000,000 m3 corresponds to an approximate 18% reduction in the downstream flow delivered to Exeter Lake (EBA 2006a). At this extraction rate a minimum downstream flow of 0.45 m3/s will be maintained from June through September. This volume is not anticipated to impact the downstream hydrological regime and was used as an upper bound for planning.

Lac du Sauvage

To fill Jay Pit and the diked area and the upper layer of Misery Pit, water will be sourced from Lac du Sauvage. Lac du Sauvage is a large lake with a surface area of 86.4 km2 and a basin area of 1,461 km2. Lac du Sauvage is tributary lake of Lac de Gras (DDEC 2014a).

It has been assumed that pumping will occur year round. Flow rates are based on maximizing use of the pumping capacity available at site at the end of operations and based on maximum withdrawal rates from Lac du Sauvage to reduce effects on natural water levels and flows from Lac du Sauvage. Two different maximum withdrawal rates from Lac du Sauvage were established to account for seasonal variability of water levels, inflows, and outflows from Lac du Sauvage. Maximum withdrawal rates of 0.4 m3/s during the November to May period (ice cover) and 1.8 m3/s during the June to October period (open water), were set (DDEC 2014a, Appendix 3A; Golder 2016a). Based on the results from the water balance model, filling of the Jay Pit and diked area would be achieved in about 3.5 years (assuming average climate conditions) (Golder 2016a); this is expected to have minimal effects to the level and local hydrological regime in Lac du Sauvage and subsequently Lac de Gras, as described in the Developer’s Assessment Report for the Jay Project (DAR; DDEC 2014a, Appendix 3A and Section 8.5.3).

The maximum seasonal withdrawal rate from Lac du Sauvage will initially be used to concurrently fill Misery Pit and Jay Pit. Once the Misery Pit freshwater cap is completed, the maximum seasonal withdrawal rate is used to complete flooding of Jay Pit and the diked area. Pumping from Lac du Sauvage will occur for a period of approximately three years following the transfer of water from the top of Misery Pit to the bottom of Jay Pit.



Lac de Gras

Lac de Gras, located south of Misery and Lynx pits, has a surface area of 572 km2 and a basin area of 3,560 km2 (DDEC 2014a). Due to its large catchment area Lac de Gras can have water draw year-round, however, due to the fact that both Lac de Gras and Lac du Sauvage are connected water bodies, water cannot be taken concurrently from both (Golder 2018a).

Pumping rates of 1.8 and 0.4 m3/s have been set from summer and winter, respectively, with a maximum annual volume of 31,100,000 m3 extracted (Golder 2018a). The pump flooding system for Lynx Pit, if required, will function for a total of one year (Golder 2018a).

Pit Lake Flooding Schedule and Infrastructure (OP-1 and OP-2)

Pit-specific descriptions of the updated pump flooding schedule and the associated required infrastructure are provided in Appendix F in detail, and a synopsis is provided in the following sections. The pit flooding sequence has been updated and optimized as part of the development of ICRP Version 3.0, with a focus on optimization of the pump flooding timeframe, number of pumps required, and pipeline design.

The pump flooding schedule and associated required infrastructure (pumps, pipelines, and access roadways) has been updated and optimized as part of the development of ICRP Version 3.0, with a focus on optimizing the time required to pump flood the pits with the infrastructure required. The optimized updated pump flooding schedule and required infrastructure is provided in Appendix F. Table 5.3-12 summarizes the open-pit flooding volumes, source lakes, and time periods. Figure 5.3-2 provides the updated pump flooding schedule.

As a result of exploring the alternative use of mined-out pits for PK deposition and for minewater management, the total volume of water that needs to be pumped from the source lakes has substantially decreased from ICRP Version 2.4 (BHP Billiton 2011a). It should be noted that the pumping schedule is based on allowable current withdrawal volumes for source lakes approved for pump flooding. The overall pump flooding schedule will be dependent on the final pit approved pit flooding plans that ensure protection of the selected source lakes.

Table 5.3-12 Open Pit Closure Pump Flood Summary

Open Pit Required Back-Flooding Volume (million m3)

Source Lake Start Pump Flooding

End Pump Flooding

Pump Duration (years)

Fox 70.0 Long Lake Containment Facility 2021 2039 19

Pigeon 12.8 Upper Exeter Lake 2023 2025 3

Lynx n/a(a) n/a(a) n/a(a) n/a(a) n/a(a)

2Sable 33.8 Ursula Lake 2027 2039 13

Beartooth 4.1 Upper Exeter Lake 2035 2036 2

Panda

22.9(b) Upper Exeter Lake(b) 2035 2039 5 Koala North

Koala

Misery 16.7 Lac du Sauvage 2035 2036 2

Jay 94.7 Lac du Sauvage 2035 2038 4

(a) Lynx Pit will be flooded operationally (combination of pumping from Phase 2 dewatering of the Jay diked area and natural precipitation) as closure

pump-flooding of Lynx Pit will only be required if Jay Pit is not developed.

(b) Panda, Koala North, and Koala pits are hydraulically connected and filled concurrently.

n/a = not applicable.



PK = processed kimberlite.

Figure 5.3-2 Pit Flooding Schedule

Panda, Koala North, and Koala Pits

Panda and Koala pits are planned to be deposition locations for PK resulting from Ekati mine operations, including mining of Jay Pit. The current design is based on PK being deposited in the Koala, Koala North, and Panda pits to an approved maximum elevation that provides space for the necessary freshwater cap. The pit flooding plan currently assumes a 30 m deep freshwater cap (WLWB-approved depth for Beartooth Pit freshwater).

After Jay pipe mining has ceased, the permanent reclamation of the Panda and Koala pits would proceed by pumping freshwater into the pits as a cap overlying the PK. The total volume of water required to flood the pits is substantially reduced compared to ICRP Version 2.4 (BHP Billiton 2011a) as a result of the PK deposition. The pipeline to flood Panda, Koala North, and Koala pits would be the same pipeline used to flood Beartooth Pit. The pipeline will begin at Upper Exeter Lake, and a new access road to the lake (approximately 1.6 km) will be constructed. Pit flooding will flow from Koala North and Koala, ultimately connecting with Panda Pit into a single coalesced pit lake at surface. Back-flooding is estimated to take approximately five years at a flow rate of 1,400 m3/h.

Beartooth Pit

Beartooth Pit is currently utilized as a PKCA and minewater management facility. Based on the current LOM, pump flooding of Beartooth Pit Lake is planned to be initiated in 2035, after PK deposition has ceased. The pumping will function seasonally for one year at a rate of 1,400 m3/h using two pumps.



Fox Pit

As there is no current mining activity in Fox Pit, passive pit flooding has been occurring since 2014. Water for Fox Pit will be pumped through a pipeline from the LLCF (DDEC 2013c). Active pump flooding is not currently planned to begin until 2021, as future opportunities at Fox Pit continue to be evaluated. One pump will be used for pumping seasonally at a flow rate of 975 m3/h. Additional road access is not expected to be required.

Misery Pit

After the completion of MUG activities, Misery Pit will be used for minewater management. Minewater stored in Lynx Pit will be pumped to the bottom of the Misery Pit and underground workings. Misery Pit will then become the primary minewater management facility for the mining of Jay Pit. At the end of LOM, the in-pit water level will be lowered to approximately 60 m below the final overflow elevation by pumping water into the lower portion of the mined-out Jay Pit. This upper 60 m (approximately 16.67 million m3) will be replaced by a cap of freshwater pumped from Lac du Sauvage. The pumping system (i.e., barge) and pipeline used for operational activity at Jay Pit will be used, with the barge pumping system being relocated to Lac du Savage, and pumping year round at a rate of 1,500 m3/h for 1.5 years. No need for additional roads is anticipated.

Pigeon Pit

Pigeon Pit flooding is planned to be started with passive flooding for the first 1.5 years after the end of operations, followed by roughly 2.5 years of active flooding starting in 2023. Due to the exposure of PAG metasediments in the pit walls, flooding of Pigeon Pit is initiated as part of progressive reclamation (see Chapter 6). Given the relatively short duration of the filling time, Pigeon Pit is expected to be the first pit to complete flooding for closure.

A pipeline would be constructed from Upper Exeter Lake to Pigeon Pit. Approximately 1.6 km of new access road will be required to access Upper Exeter Lake. A pumping rate of 1,400 m3/h from Upper Exeter Lake is planned during the open water season (1 June to 31 October). This will be achieved by two pumps, configured in parallel to operate at 700 m3/h per pump.

Lynx Pit

During the operation of MUG, Lynx Pit will be used for minewater management. Lynx Pit will hold minewater from MUG that contains elevated concentrations of TDS. When MUG closes, the water will be pumped out of Lynx Pit to the bottom of Misery Pit.

Subsequently, as part of Jay Pit construction, Lynx Pit (in conjunction with Misery Pit) will be used as a settling facility for TSS-laden water during the final dewatering of the diked area of Lac du Sauvage. This approach makes best use of water from the diked area and reduces the volume of water that needs to be drawn from other source lakes. Lynx Pit has an estimated maximum storage capacity of approximately 6.7 million m3. However, only 4.9 million m3 of TSS-laden water will be pumped to Lynx Pit. The remaining volume will be filled with natural net inflows over an estimated 5.5 years. The years needed for flooding are expected to be sufficient to allow for TSS settling within Lynx Pit Lake.

Should Jay Pit development not proceed, a contingency of pump flooding of Lynx Pit would involve a pipeline system beginning at Lac de Gras transporting water to Lynx Pit over a distance of approximately 1 km. A new access road for the pipeline also approximately 1 km long would be required. Two pumps at a rate of 750 m3/h per pump would be used seasonally over the course of a year.



Sable Pit

Sable Pit will be back-flooded with freshwater, including a four-year period of passive flooding followed by active flooding from Ursula Lake. The Sable pipeline system will begin at Ursula Lake and will transport water to Sable Pit over a distance of approximately 4 km. A new access road of approximately 1 km will be constructed. It is estimated that the pit can be filled over 13 years by pumping seasonally at a mean rate of 700 m3/h during the open water season (1 June to 31 October) using one pump.

Jay Pit

Jay Pit and the diked area will be back-flooded at closure. At completion of mining the Jay pipe, and as part of the closure measures for Misery Pit, high TDS water from Misery Pit will be pumped into the bottom of the mined-out Jay Pit, where it will occupy the lower portion of the pit. Once this has been completed, the remaining volume of Jay Pit and the diked area will be back-flooded with water from Lac du Sauvage (supplemented by groundwater inflows, runoff, and direct precipitation). The pumps and piping used in the dewatering of the diked area for Jay Pit will be used. No additional access roads are expected to be needed. Water from Lac du Sauvage will be pumped over the dike in a controlled manner to control the generation of TSS. Pumping rates will vary from 1,500 to 6,500 m3/h depending on the season and status of Misery Pit back-flooding. The pumping will occur year round and is planned to commence in mid-2036 and last three years. Once water quality within the back-flooded area meets acceptability criteria, the dike will be locally breached and the Sub-Basin B Diversion Channel will be reclaimed to promote natural drainage through existing flow paths (see Section 5.7 for details).

5.3.5.3. Closure Measures

Pit Flooding Plan (OP-2)

A final pit flooding plan will be submitted to the WLWB for approval prior to initiating active flooding. This plan will outline the pit-specific withdrawal and monitoring plans to minimize effects to source lake aquatic habitats during pit flooding. Specific to the Jay Project, a back-flooding pumping plan will be developed for the WLWB to protect fish habitat and movement in the Narrows during closure, as per Measure 5-1 of the REA (MVEIRB 2016) and Part K, Condition 8 of the Water Licence. The Jay back-flooding plan will incorporate the results of AEMP and hydrological monitoring at the Narrows conducted during construction and operations including depths and widths under naturally occurring low-flow conditions in the winter.

Littoral Zones (OP-3)

Building from Section 5.3.4.1, and consistent with past discussions related to littoral zone design, for the pits that are selected in the future, Dominion will prepare pit-specific design reports for the WLWB’s approval that describe the works to be constructed in pit lake littoral zones and connector channels. The final design of the pit lakes’ littoral zones and connector channels will be pit specific, working within the unique physical and environmental constraints of the pit lake. Approval of the final design for littoral zones and connector channels will represent the WLWB’s complete review of the work that is required to achieve the closure objective. Specifically, the concepts of “facilitating,” “establishment,” “self-sustaining,” and “aquatic ecosystem” will be fully resolved with approval of the final design. The “built as designed” criteria will be fully achieved when Dominion has constructed according to the approved final design using good engineering practice. Dominion is not responsible for monitoring or proving the establishment of a self-sustaining aquatic ecosystem (BHP Billiton 2011a).



Outflow and Connector Channels (OP-4, OP-5)

The pit lakes are intended to be connected to the local watershed via connector and outflow channels once the water quality in the pit lakes has met closure water quality criteria. Closure objectives are that outflow and connector channels on site are stable to a degree that is consistent with natural channel stability, and where possible, that these channels are able to support fish passage. Indigenous Elders from the TKEG expressed concern about the settling of particulate matter at inflow and outflow channels and inquired if monitoring for particulate matter would be conducted (DDEC 2017j).

In support of closure planning, EBA (2013) completed a study that evaluated anticipated fluctuation in pit lake elevation post-closure, and preliminary design of closure connector and outflow channels for Panda, Koala, Koala North, Beartooth, Fox, Misery, and Pigeon pits. Based on this work, outflow channels are designed to flow into existing streams, preferably along the preconstruction channel alignment. Outflow channels are designed to be of sufficient length to establish a connection from the pit lake to the existing channel. This typically involves excavating through the existing mine infrastructure at the outlet. No modifications or alterations to the existing channels beyond the outflow excavation limits are proposed. All channels are designed to be lasting features that are not expected to require maintenance. Given the consistently low flows, the outflow channels have been designed with a consistent trapezoidal cross-section, having a 0.5 m base and 3H:1V sideslopes. While the EBA report did not specifically consider Sable or Lynx pits, the same general approach will be applied.

The planned inflow/outflow of each pit lake is described in Table 5.3-13. The final closure design for outflow and connector channels will be based on criteria that will allow these features to continually function in the post-closure period without the need for ongoing inspection and maintenance. Final pit lake elevations, expected seasonal lake level fluctuations, pit perimeter topographic characteristics, discharge volumes, channel slope, and bank width will all be included as part of the engineering design for outflow and connector channels. Channel banks will be stabilized, if needed, through rock armouring and/or plant establishment to prevent erosion. The design will acknowledge that fish access into and out of the pit lakes through outflow/connector channels may be intermittent and may not be possible every year based on natural flow conditions in the small catchment areas around the pit lakes.

Consistent with the approach to littoral zone design, Dominion will prepare pit-specific design reports for the WLWB’s approval that describe the works to be constructed to facilitate fish passage. The final design will be pit specific, working within the unique physical and environmental constraints of the pit lake.

Table 5.3-13 Pit Lake Surface Drainage Post-closure

Pit Lake Outflow Channel Description

Pigeon • The PSD will remain in place post-closure (see Section 5.7). This will continue the diversion of Pigeon Stream around Pigeon Pit Lake to Fay Bay.

• The berm on the southern end of Pigeon Pit Lake will be breached to enable surface runoff into the pit lake. • Outflow from Pigeon Pit Lake will be connected to lower Pigeon Stream, which flows into Fay Bay; the original Pigeon Pond

outflow channel will be used. Due to the small catchment area contributing to Pigeon Pit Lake, flow is anticipated to be intermittent.

Beartooth • Flow will be re-established from Bearclaw Lake through Beartooth Pit Lake by breaching the Bearclaw Dam and constructing an inflow stream that makes use of the pre-existing flow path.

• An outflow channel to Upper Panda Lake will be established. The preliminary design has the outflow located at the southeast side of the pit at a 3.4% grade, and follows the pre-construction flow path. Air photos show the existing channel to be rocky and poorly defined. Survey data indicate natural channel grades of up to 5% and 6% (EBA 2013)

Fox • Discharge from Fox Pit Lake will be directed northeast to One Hump Lake. This outflow will represent a new flow path, as the pre-disturbance flow path from Fox Lake has been subsumed by the WRSA.

• In order for the discharge to flow eastward, the Fox Pit Lake level will be raised above the original Fox Lake level. The design grade through the outflow is approximately 0.2%.

• Channel excavation will be required through existing infrastructure adjacent to the proposed discharge. Excavation will also be required through the pads constructed as part of the Fox decline, to establish a flow path to One Hump Lake (EBA 2013).



Pit Lake Outflow Channel Description

Sable • An outflow channel will be constructed from Sable Pit Lake to Two-Rock Lake. • The internal Two-Rock Dike and Two-Rock Dam will be breached, and an outflow channel constructed to Horseshoe

Lake that makes use of the pre-existing flow path.

Lynx • The outflow from Lynx Pit Lake will discharge to Lac de Gras in a manner that makes use of the pre-existing flow path (Golder 2016b). Consistent with pre-disturbance conditions, due to the small catchment area, flow is anticipated to be intermittent.

Misery • The outflow from Misery Pit Lake will overflow to Lac de Gras, utilizing the pre-development channel. • The outflow is designed with a grade of 0.5%; the outer ring road will have to be breached to maintain positive flow

(EBA 2013). • Grades in the natural streambed steepen significantly as the channel approaches Lac de Gras, which may influence

fish connectivity.

Panda/Koala/ Koala North

• The PDC will remain in place post-closure (see Section 5.7). This will continue the diversion of the majority of flow from Upper Panda Lake around Panda and Koala Pit lakes to Kodiak Lake.

• A spillway will be constructed around the Panda Dam that will allow safe passage of flood flows. This is a precautionary measure to protect against general flooding of the area in a flood event or if the PDC is temporarily blocked with snow during freshet.

• A connector channel between Panda Pit Lake and Koala Pit Lake (which will include a flooded Koala North Pit) will be constructed to reconnect surface drainage.

• An outflow channel from Koala Pit Lake to Kodiak Lake will be constructed. The outflow discharges from the south side of Koala Pit at a 0.15% grade, following the pre-disturbance flow path (EBA 2013). This will entail constructing the outflow channel through the existing infrastructure (haul road and airport access road) to discharge to the pre-construction stream bed and eventually Kodiak Lake. Survey data show the natural streambed to be very flat, with large stagnant areas.

Jay • The Jay Dike will be strategically breached to allow mixing between the main body of Lac du Sauvage and the (previously) diked area overlying Jay Pit (Golder 2016b).

PSD = Pigeon Stream Diversion; WRSA = waste rock Storage area; PDC = Panda Diversion Channel.

Safe Pit Egress (OP-6)

In the post-closure state, the pit lake perimeter will include sections of steep highwalls that remain above the water surface and sections of lake edge that transition into adjacent terrestrial habitat. Observations of active and inactive pit walls at site have shown that these areas will provide nesting locations for raptors and other bird species. Also, by achieving the water quality closure objective, it is expected that pit lakes will be inherently safe for use by waterfowl. As described in the section on littoral zones (Section 5.3.4.1), the pit lake environment will differ from that of a natural lake in that it will have steep-sided banks and a very deep bottom. It is not anticipated that the pit lakes will become popular areas for mammals or human use post-closure; however, the potential for inadvertent or infrequent access is acknowledged, and the steep sided banks may make egress challenging. Therefore, Ekati mine closure objectives include factoring in safe egress for wildlife and people into the design of final pit lake perimeters.

Three aspects of the pit lake structure are important with respect to egress:

• Existing pit ramps will be left in place to facilitate egress.

• The pit lake outflow and connector channels will represent natural points of egress, which could be further enhanced through proactive engineering design.

• For pits that include construction of littoral zones, egress will be facilitated.



As part of the final closure design for each pit lake, these three areas will be specifically considered for facilitating safe egress. In addition to providing areas of shallow depth and slope that can provide secure footing, it will also be possible to incorporate riparian vegetation or other natural shoreline landmark features that could help to alert wildlife/humans to the presence of a zone of safe egress. Details of such measures will be incorporated into the closure design over time, guided by data collected during the WEMP in combination with TK from Indigenous communities.

5.3.5.4. Uncertainties

Engineering designs and plans for open-pit closure works such as including the pit lake littoral zones, connector and outflow channels, and protection of source lakes will continue to be refined and presented to stakeholders and the WLWB in future versions of the ICRP, with final versions being outlined as part of the Final Closure and Reclamation Plan. Final versions of designs and plans may also be developed earlier if the closure work is selected to be undertaken as progressive reclamation. Reclamation uncertainties are specific reclamation items that require addressing through reclamation research. Provided in Table 5.3-14 are the two identified reclamation uncertainties and a summary of how they will be address through reclamation research and monitoring. The referenced research plans are provided in Appendix E.

Table 5.3-14 Open Pit Closure Uncertainties

Uncertainty Research Plan to Address Uncertainty

There is a potential uncertainty that the 30 m freshwater cap depth over PK materials in Beartooth and Panda Koala Pits. This could be as a result of poor porewater quality resulting from PK consolidation, runoff from WRSAs and exposed pit walls.

RP 2 – Panda/Koala Closure Freshwater Cap Depth

There is a potential uncertainty that the 60 m cap over minewater in Misery Pit, as established through current water quality modelling will not result in water quality that will meet closure water licence criteria as a result of diffusion from the monimolimnion in a meromictic lake.

RP 3 – Misery and Jay Meromictic Pit Lake Freshwater Cap Depth

PK = processed kimberlite; WRSA = waste rock storage area; RP = research plan.

5.3.5.5. Post-closure Monitoring, Maintenance and Reporting

Source Lakes

Pumping rates will be recorded, and water levels and outflow hydrology will be monitored at each source lake during the period of active pumping to verify that there are no impacts for aquatic habitat.

Pit Lake Water Quality

Pit lake water quality measurements will be completed during and post-flooding to demonstrate that the Water Licence closure criteria have been met and the water quality objective has been achieved.

The overall duration, scope, and frequency of pit lake monitoring will be dependent on the specific pit that is being monitored and will also be dependent on the observed monitoring trends and results.

Littoral Zones

As-built drawings will be prepared for any constructed littoral zones to document the specific features, and to show that the area has been built to specification.



Outflow and Connector Channels

Closure monitoring of the outflow and connector channels will be completed to demonstrate that the channels are stable and resilient to natural events. Monitoring will include looking for signs of significant erosion, subsidence, slope failure, and surface instabilities. If required, observed localized instabilities will be addressed through preventative maintenance. Stream flow monitoring at the pit lake outflow will also be completed to verify that the pit lake outflow channel is effectively routing water to the Receiving Environment.

Safe Egress

Wildlife use of the open-pit areas will be tracked through site-wide monitoring efforts. If monitoring results indicate higher use at one of the pit lake areas than expected, targeted monitoring (e.g., camera locations) may be warranted to track use and egress.

Reporting

A report summarizing site activities, compliance, and environmental data will be prepared as required by the Water Licence (currently annual and may change as closure progresses) and the Environmental Agreement (annual). Additionally, the three-year EIR report will be prepared as required by the Environmental Agreement. These mechanisms will provide a consistent reporting regime for reclamation activities and progress.

A reclamation completion report will be prepared for specific mine components to document when closure objectives have been achieved and relinquishment can proceed (see Section 5.2 for more information on relinquishment documentation).

5.3.5.6. Predicted Residual Effects

Residual effects related to the successful completion of the open-pit closure works are provided in Table 5.3-15. These are consistent with the findings from previous EAs (BHP and Dia Met 1995, 2000; DDEC 2013d, 2014a) and ICRP Version 2.4 (BHP Billiton 2011a).

Table 5.3-15 Residual Effects Following Reclamation of the Open Pits

Land Use Effects (Wildlife and Human Use) Environmental Effects

• Landscape is altered through the removal of Sable, Panda, Pigeon, Beartooth, Koala, Fox, Misery, and Lynx lakes and conversion to pit lakes at closure.

• Wildlife and human movement may be affected by landscape alteration and remaining closure structures (noting that residual pit walls are anticipated to provide good nesting habitat for raptors).

• Nutrient sinks are present in pit lakes due to increased depths of pit lakes, and as a result, their ecological productivity is lower than adjacent natural lakes.



5.3.5.7. Residual Risk and Contingencies

Acknowledging that there always remains some level of risk that certain reclamation activities are not as successful as expected, a summary of key identified risks and associated high level contingency measures are provided in Table 5.3-16. Given the current stage of mine development, it is not reasonable to provide greater detail at this time. In practice, should the post-closure monitoring programs identify that conditions are trending in the wrong direction, adaptive management measures will be implemented to adjust to the reclamation activity, closure criteria, or monitoring program so that that closure objectives are achieved. In some cases, response thresholds will be developed and included in the closure monitoring to identify trends when closure criteria will be exceeded and the potential for closure objectives not being met. The refinement of the adaptive management framework for post-closure will continue with future updates of the ICRP.

Table 5.3-16 Key Residual Risks and Contingencies for Open Pits

Key Residual Risks Contingency

Water quality in pit lake(s) does not meet closure criteria to allow release to the Receiving Environment

• Conduct ongoing water management or treatment of poor water quality until Water Licence criteria are achieved. This would likely consist of decanting poor quality water inside the pit and reflooding with freshwater. Decanted water will be managed at established water polishing infrastructure at the LLCF or by other means.

• Increase natural flow through the pit lake. This could involve routing of natural flow into the pits from the PDC and the Pigeon Stream Diversion or other means.

• Evaluate water management options to reroute water (e.g., use pit water to flood lower portions of adjacent pit that is not yet fully flooded).

LLCF = Long Lake Containment Facility; PDC = Panda Diversion Channel.

5.4. Underground Mine Workings

5.4.1. Pre-disturbance Conditions

The Panda, Koala, Koala North, and Misery underground mines are located within the area of the pits of the same name. Pre-disturbance conditions for these locations can therefore be found in Section 5.3, with the corresponding pits. Additional detail on site-wide pre-disturbance conditions is provided in Chapter 3 with the discussion of baseline site conditions.

Pre-disturbance groundwater at underground workings that extend below permafrost is connate groundwater, which was trapped in pores in the rock at the time the rock was formed. This fossil water can be highly saline, and its salinity increases with depth.

5.4.2. Existing and Final Conditions

Underground developments at the Ekati mine are associated with pits. When economic to do so, underground workings are used to mine the deeper portions of kimberlite pipes below an initially mined open pit. Four underground mines are expected to have been developed by the end of operations, with characteristics as summarized in Table 5.4-1. The dates shown are based on the 2018 LOM Plan, with future dates projected and subject to modification. Further detail on both the past and planned mining schedule is shown in the integrated schedule of activities (Chapter 8). Underground mining methods used at the Ekati mine are discussed in Section 4.3.



The Panda, Koala North, Koala, and Misery underground workings are directly below and connected to the overlying open pits and, therefore, the closure of these workings is closely related to the closure of open pits as discussed in Section 5.3. The main infrastructure associated with Panda, Koala North, Koala, and Misery underground mines is summarized in Table 5.4-2.

Table 5.4-1 Summary of Ekati Underground Mines

Underground Mine Development Start End of Mining Mining Method

Koala North 2002 test(a) 2010

2004 test(a) 2014

Sublevel retreat

Panda 2004 2010 Sublevel retreat

Koala 2004 2018(b) Sublevel caving, later incline caving

Misery 2018(b) 2022(b) Sublevel retreat

(a) Operation as a test mine to determine what types of equipment, materials, and processes worked best in Arctic permafrost underground conditions.

(b) Projected dates based on WLWB approval of the MUG Project.

WLWB = Wek'èezhı̀ı Land and Water Board; MUG = Misery Underground.

Table 5.4-2 Ekati Underground Mines and Associated Infrastructure

Underground Mine Infrastructure Underground Mine Infrastructure

Panda Panda conveyor portal Koala Refuge stations (3)

Panda conveyor system Equipment service bay

Panda sizer (includes conveyor control room) Fuelling bay

Explosives magazine (3)

Primary dewatering system Electrical distribution system

Refuge stations (5) Rock breaker

Explosives magazine (3) Conveyor system

Wash bay Conveyor control room

Equipment service bay (2) Sizer

Fuelling bay Dewatering system

Electrical distribution system Fresh air raises (2)

Rock breaker Return air raise (1)

Fresh air raises (2) Man-way raise (1)

Return air raise (2) Koala ore pass

Man-way raise (1) Equipment service bay (1) Koala North Koala North Portal Koala adit

Refuge stations (3) Misery Surface portal or in-pit portal access (2)

Communication tower and trailer

Explosive magazine (1) Dewatering system Electrical distribution system Fresh air raise (1)

Fresh air raises (2) Power line connector to Misery substation

Man-way raise (1) Compressed air supply system

Return air raise (1) Type 4 explosives magazine (3)

Rock crusher



Figure 5.4-1 outlines the extent of underground mine workings at Panda, Koala, and Koala North. These workings are interconnected, sharing common access and ventilation systems.

Figure 5.4-2 outlines the extent of planned underground mine workings for MUG. MUG will be an extension of the mining operations at the Misery Pit area. It will involve the use of existing infrastructure, along with the development of limited new infrastructure to support underground mining operations, allowing the recovery of high value kimberlite from deeper portions of the Misery kimberlite pipe. Development of MUG will require approximately 1.5 years of initial underground development activities, followed by underground ore extraction over about 2.5 years, producing the equivalent of about six months of full-time feed to the Ekati mine processing facilities.

Provided by DDEC June 2018

EKA-18ERM-058a 0 5.4-1PROJECT NO. CONTROL

CLIENT

PROJECT

EKATI DIAMOND INTERIM CLOSURE AND RECLAMATION PLANVER. 3.0TITLE

Underground Mine Workings at Panda, Koala, and Koala North

REV.

0211136-2015-0301

NOTE(S)

REFERENCE(S)

2018-06-22

J W

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED

FIGURE

Koala Pit

North Koala Pit

Panda Pit

0 200 400

Metres

J R

LN

J W

Image: July 2017 imagery provided by DDEC.Open pit and sub-level retreat configuration: DDEC 2017. Misery Underground Prefeasibility Study, Figure 22.Isometric Cross Section Misery Pit: DDEC 2016. Ekati Diamond Mine NI 43-101 Technical Report, Figure 7-8. EKA-18ERM-058b 0 5.4-2

PROJECT NO. CONTROL

CLIENT

PROJECT


Planned Underground Mine Workings at Misery

REV.

0211136-2015-0301

NOTE(S)

REFERENCE(S)

2018-05-17

J W

J R

LN

J W

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED

FIGURE



5.4.2.1. Panda/Koala/Koala North Underground

The current extent of the Panda, Koala, and Koala North underground mines is shown in Figure 5.4-1. As shown in this figure, all three of these underground developments are located in close proximity, and conditions at the three are linked. Two tunnels connect Panda Underground with Koala North Underground, and one shaft connects Koala Underground with Koala North Underground.

Access to the Panda, Koala North, and Koala underground mines was established via the Koala North Portal located adjacent to Koala North Pit. Panda Underground is also connected to the surface by a 2.4 km long tunnel called the Panda Conveyor Ramp, which opens to the north of the processing plant.

Additional conveyor systems that connect the crushing system to the Panda Conveyor, and a 1.0 km long conveyor ramp linking Koala Underground to the Panda Conveyor Ramp, were constructed in 2006 and 2007. This conveyor ramp is used to bring kimberlite ore to surface. Koala North Underground has two 3 m wide fresh air raises that extend to surface. The Koala and Panda underground mines each have two 4 m wide fresh air raises plus one return air raise that extend from surface to underground. The fresh air raises are fitted with large ventilation fans. Only infrastructure necessary for access and transportation to and from the Koala Underground workings is still actively used.

Panda Underground mineral reserves are exhausted and operations ceased in 2010. All salvageable equipment, hazardous materials, and other waste products have been removed from Panda Underground. The accumulation of seepage inflows into the Panda workings is actively maintained by pumping below safety thresholds that prevent spillage into the Koala workings. The underground minewater is pumped to Beartooth Pit or the LLCF along with Koala Underground minewater.

Koala North Underground operations have also been completed. Production ceased in 2014 and, like Panda Underground, these workings have been “cleaned out” (reclaimed).

Koala Underground is currently in production, with production estimated to continue until the latter part of 2018. Mining areas are reclaimed (cleaned out) as they are completed. Once mineral reserves are exhausted, remaining salvageable equipment, hazardous materials, and other waste products will be removed. It is currently anticipated that Panda/Koala will be ready to receive PK deposition in early 2019.

At the end of LOM, underground operations will be below the pit lakes described in Section 5.3. Panda, Koala, and Koala North underground workings will be filled with PK, as part of the PK deposition in the associated pits. Openings to surface that are not within an open pit will be sealed.

5.4.2.1. Misery Underground

Preparatory work for the MUG Project has begun and mining of MUG is scheduled to begin in 2018 and is planned to last for 2.5 years. After the completion of underground mining, MUG will be flooded with MUG Project minewater that had been stored in Lynx Pit during MUG Project operations. Misery Pit, including the underground workings, will later be used as a water management facility to support Jay Pit operations. Prior to flooding of the underground workings, salvageable equipment, hazardous materials, and other waste products will be removed. Detailed design and portal selection is currently in progress; any openings to surface that are not within the open pit will be sealed.


Based on the goals and principles for the Ekati ICRP, closure objectives were identified specifically for the closure and reclamation of the underground mine workings. Reclamation activities and monitoring and reporting corresponding to the objectives and criteria are summarized for each objective in Table 5.4-3 and are discussed further in Section 5.4.6.



Table 5.4-3 Closure Objectives and Criteria for Underground Mine Workings


UG-1 Hazards from potential access to underground workings are mitigated.

At surface, cap vent raises and seal portals.

Vent raise caps and portal seals are designed and constructed per the Mine Health and Safety Act.

As-built drawings (construction meets design specification)

UG-2 Hazardous materials in the underground do not pose risk to underground water quality.

Inventory and remove hazardous materials in the underground mine and send to appropriate facilities.

Documented removal of hazardous materials (i.e., fuel, oils, glycol, batteries, explosives, and electrical transformers).

Physical inspection of underground works by GNWT inspector

GNWT = Government of the Northwest Territories.


Feedback from community visits conducted in 2018 suggests concerns that PK, cables, wiring, or other hazardous materials remaining underground could adversely impact water quality and the ability for communities to drink water. Others noted that the land where underground mine workings are would never return to a pre-mining state.

5.4.5. Consideration of Closure Options and Selection of Closure Activities

No specific options have been identified as closure of the Ekati underground mines is straightforward and will consist of flooding the underground along with the open pits.



Each area of underground mining will be subject to the following list of closure activities:

• Identify and remove material and mobile equipment with salvage value.

• Remove any potentially hazardous materials or other materials with the potential for negative effects on water quality and dispose of them in an authorized facility, on site or off.

• Deposit PK/minewater in underground workings (see Section 5.3 for further information).

• Seal any remaining portals to the surface, following design indications of the Mine Health and Safety Act (GNWT 2010).

• Install vent raise caps on any remaining raises exposed at the surface, following design indications of the Mine Health and Safety Act (GNWT 2010).





Underground Progressive Reclamation

Where possible, progressive reclamation of the underground workings has been and will continue to be completed prior to PK/minewater deposition. Progressive reclamation activities to date have predominantly consisted of the removal of hazardous materials from the underground levels and the disposal of those materials in the appropriate facilities as per the Waste Management Plan and related documents. Hazardous materials include fuel, oils, glycols, batteries, explosives, or electrical transformers. The reclamation activities that have occurred to date were documented in annual progress reports (see Section 6 for more information).


Seal Underground Access (UG-1)

All portals into the underground mines and fresh air raises will be sealed per the NWT Mine Health and Safety Act (GNWT 2010). The Act states that entrances to underground mines that are dangerous by reason of their depth or otherwise should be suitably protected against inadvertent access [Section 17.03 (1)]. The Panda and Koala return air raises are located well within the open pits where they will be inaccessible during pit flooding and ultimately well submerged under pit lake water and/or PK for closure. Final siting for MUG portals is still to be determined. Backfilling and/or capping of the seals will be designed to conform to the surrounding area. As an example, the Fox Portal entrance used during the exploration phase to access the Fox pipe has been plugged with waste rock excavated from the decline. The profile at the entrance conforms to the natural terrain within the area.

Hazardous Waste Material Removal (UG-2)

Once underground operations are complete in a particular area, closure activities will occur as progressive reclamation (Chapter 6) in advance of utilizing the overlying open pit for alternate use (e.g., PK storage, minewater management), where applicable. Oxygen bottles and chemical cleaners and all materials with potential for chemical degradation that are located in the maintenance shops (e.g., petroleum products, batteries) will be removed from the underground. Material and equipment that is not considered to be salvageable and will not negatively affect water quality (including fixed equipment, rock breaker, and conveyor system that have been cleaned of fuels and lubricants) will remain in the underground rather than being hauled to surface and buried in a landfill. Explosives supplies are only maintained in one- to two-day quantities underground, so there will be limited amounts on site when underground mining is complete. Any explosives remaining underground will be removed and disposed of safely. Prior to flooding being initiated, physical inspection by the GNWT inspector will be completed to confirm that hazardous waste materials and materials potential for chemical degradation have been removed from the underground workings prior to PK/minewater deposition.

5.4.7. Uncertainties

Closure of the Ekati underground mines is considered relatively straightforward, and built upon past experience at Panda and Koala North. There are some uncertainties about the potential for connectivity from the Lac de Gras talik and the MUG workings; however, this is largely a challenge during operations. Flooding of the underground workings would re-establish a hydraulic gradient to stem groundwater flow paths.

Planning for the closure of underground mine workings will continue to be refined leading up to the implementation of closure works. In the short term, this relates to the scheduling and resourcing of activities associated with the cessation of mining in Koala Underground, and will similarly be completed upon cessation of mining in MUG. However, additional design work or reclamation research is not expected to be needed at this time to address residual uncertainties.



5.4.8. Post-closure Monitoring, Maintenance, and Reporting

The proposed post-closure monitoring and reporting to achieve the closure objectives for the underground mine workings will include:

• physical inspection by the GNWT inspector to confirm that hazardous waste materials and materials potential for chemical degradation have been removed from the underground workings prior to PK/minewater deposition

• as-built drawings of seals of vent raises (construction meets design specification) to ensure that hazards from access to underground workings have been mitigated

• annual visual inspection of the seals for a limited period of time (five years) to demonstrate that they are functioning and stable as per design.

No ongoing maintenance activities are envisioned to be required for the underground workings. Final documentation of the monitoring results will be provided as part of final relinquishment documentation in demonstration that the closure objective have been achieved (see site-wide relinquishment reporting objective, SW-8, in Section 5.2).

5.4.9. Predicted Residual Effects

An assessment of potential negative residual effects that may remain in the underground mine component after reclamation work has been completed. In ICRP Version 2.4 (BHP Billiton 2011a), no significant effects were identified for the post-closure phase of Panda/Koala/Koala North underground workings; potential effects of underground mines affecting pit lake water quality were considered negligible. These conclusions remain valid.

MUG can be operated in a manner that, taking into account proven environmental design features, mitigation, and administrative controls, is not likely to cause significant adverse effects to the biophysical or socio-economic environments (DDEC 2017k).

5.4.10. Residual Risk and Contingencies

The closure and reclamation of the underground installations is subject to a much lower degree of uncertainty as compared to other aspects of closure. Inundation of underground works and portal seals are relatively standard closure measures, and have been demonstrated to be reliable and effective at many sites around the world. Due to the lower uncertainty, specific contingencies are not defined for this component.

Nevertheless, in the case of unforeseen events, the principles of adaptive management, which have been applied at the Ekati mine since mine development began in 1997, would underpin the approach to any unanticipated contingencies.

As with any geotechnical structure, adit or raise seal could be subject to greater than predicted settlement or erosion. This is considered a monitoring and maintenance issue (as discussed in a previous section), and does not necessitate a specific contingency plan.



5.5. Waste Rock Storage Areas

5.5.1. Waste Rock Storage Area Description

5.5.1.1. Pre-disturbance Conditions

Pre-disturbance conditions applicable to WRSAs are summarized in this section. A comprehensive discussion of baseline site conditions (equivalent to pre-disturbance conditions) across the entire site is provided in Chapter 3 of this document.

Panda/Koala/Beartooth Waste Rock and Coarse Kimberlite Reject Storage Areas

The Panda/Koala/Beartooth WRSA and CKRSA is located immediately to the west of Panda and Koala pits. The pre-disturbance conditions of the Panda/Koala/Beartooth WRSA and CKRSA were predominantly till and tundra. Granitic country rock outcrops were located in sparse patches throughout the area. The pre-disturbance terrain within the Panda/Koala/Beartooth WRSA consisted of low relief with elevation variations of approximately 15 m. Several small ponds were scattered to the north and east of the Panda pipe. The pre-disturbance vegetation and wildlife conditions of the WRSA were typical of the Ekati claim block.

Fox Waste Rock Storage Area

The Fox WRSA is located in a horseshoe pattern around Fox Pit and covers the western, southern, and eastern areas immediately adjacent to the pit. Prior to disturbance, the Fox Lake area was surrounded by a till veneer containing pebbles, cobbles, and boulders in a silty matrix. The till veneer thickness was generally less than 2 m. The WRSA is located within the Koala watershed, with the southern tail of the original Fox Lake draining to the southwest. The vegetation and wildlife conditions prior to disturbance of the area around the Fox WRSA were typical of the Ekati claim block.

Sable Waste Rock Storage Area

The pre-disturbance conditions of the Sable WRSA were rolling ground moraine up to 15 m thick that underlaid terrain west and northeast of Sable Lake. Individual and concentrated boulders were found on the ground surface at some locations. The vegetation and wildlife conditions prior to disturbance of the area around the Sable WRSA were typical of the Ekati claim block.

Pigeon Waste Rock Storage Area

The Pigeon WRSA was placed over Big Reynolds Pond south of the Pigeon Pit. Prior to disturbance, the area around the Pigeon WRSA was covered with a thin till veneer with well-defined stony earth circles on its surface. An isolated kame consisting of partially water-sorted and crudely stratified sand and gravel lay north of the kimberlite pipe and approximately 500 m north of Pigeon Pond. South and east of Pigeon Pond, the terrain consisted of rolling ground moraine covered with glacial till up to 15 m thick. The location of the WRSA is within the LLCF drainage basin, and all seepage and runoff from the pile drains toward the LLCF. The vegetation and wildlife conditions prior to disturbance of the area around the Pigeon WRSA were typical of the Ekati claim block.



Misery/Lynx Waste Rock Storage Area

The Misery WRSA is located immediately northwest of Misery Pit, and the Lynx WRSA is an extension to the northwest of the Misery WRSA. The pre-disturbance topography and conditions of the Misery Lake area were characterized by low to moderate relief with rolling hills and low-lying muskeg areas. Topographic variations correspond to the change in lithology from strongly resistant granitic rocks expressed by positive relief to less resistant schist and low-relief. Moraine, kames, and eskers and a till veneer are common in the area of the Misery WRSA. The vegetation and wildlife conditions prior to disturbance of the area around the Misery WRSA were typical of the Ekati claim block.

Jay Waste Rock Storage Area

The Jay WRSA will be located on the western shore of Lac du Sauvage, northwest of Jay Pit, and a minimum of 200 m from the adjacent north–south Lac du Sauvage esker. The pre-disturbance topography and conditions of the area are characterized by low relief with bedrock outcrops to a veneer to blanket morainal deposits of boulders, sands, gravels, and silts, along with some glaciofluvial sand and gravel deposits over bedrock. The vegetation and wildlife conditions prior to disturbance of the area around the Jay WRSA were typical of the Ekati claim block.

5.5.1.2. Existing and Final Conditions

The locations for the eight existing and permitted WRSAs are shown on Map 5.5-1. A summary of the operational status, rock and materials contained, existing and final maximum design height, and footprint is provided in Table 5.5-1. The heights for the WRSAs are calculated from the average tundra elevation adjacent to the respective WRSA. A summary of the material quantities currently deposited in each WRSA is provided in Table 5.5-2 and an estimate of the future material tonnages is provided in Table 5.5-3.

A summary of the existing and final conditions for the WRSAs at the Ekati mine is provided in the subsections below.

SABLE DEVELOPMENT

BEARTOOTH/PANDA/KOALA DEVELOPMENT

LONG LAKECONTAINMENT FACILITY

MAINCAMP

AIRSTRIP

FOX ROAD

FOX DEVELOPMENT

JAY DEVELOPMENT (FUTURE)

MISERY ROAD

MISERY CAMP

MISERY DEVELOPMENT

LYNX DEVELOPMENT

JAY ROAD

SABLE ROAD

SABLE WRSA'S

PIGEON WRSA

BEARTOOTH/PANDA/KOALA WRSA

FOX WRSA

LYNX WRSA

JAY WRSA

MISERY WRSA

CKRSA

LAC DU SAUVAGE

LAC DE GRAS

DUCHESSLAKE

PAUL LAKE

URSULA LAKE

COUNTS LAKE

EXETER LAKE

LAKE B1(CHRISTINE LAKE)

500000

500000

510000

510000

520000

520000

530000

530000

540000

540000

550000

550000

7160

000

7160

000

7170

000

7170

000

7180

000

7180

000

7190

000

7190

000

PAT

H: I

:\CLI

EN

TS\D

OM

INIO

N\1

7765

30\M

appi

ng\M

XD

\ICR

P\1

7765

30_M

ap5_

5-1_

Was

teR

ockS

tora

geA

reas

.mxd

PR

INT

ED

ON

: 201

8-08

-14

AT: 7

:27:

36 A

M

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT

1. BASE DATA OBTAINED FROM GEOGRATIS, © DEPARTMENT OF NATURAL RESOURCESCANADA. ALL RIGHTS RESERVED.PROJECTION: UTM ZONE 12 DATUM: NAD 83

PROJECT

EKATI MINE INTERIM CLOSURE AND RECLAMATION PLAN VER.3.0TITLE

WASTE ROCK STORAGE AREAS

MAP EXTENT

Sources: Esri, HERE, DeLorme,TomTom, Intermap, increment PCorp., GEBCO, USGS, FAO, NPS,NRCAN, GeoBase, IGN, Kadaster

KEY MAP

0 5,000 10,000

1:175,000 METRES

LEGENDELEVATION CONTOUR (10 m INTERVAL)

WINTER ROAD

WATERCOURSE

WATERBODY

CLAIM BLOCK BOUNDARY

EXISTING EKATI MINE FOOTPRINT

FUTURE FOOTPRINT

WASTE ROCK STORAGE AREA

REFERENCE(S)

1776530 3000 0 5.5-1

2018-08-14

MJ

AB

BW

LN

PROJECT NO. CONTROL REV. MAP

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED



Table 5.5-1 Waste Rock Storage Areas Summary Characteristics

WRSA Material Deposition Areas and Operational Status

Current Maximum Height (m)

Final Maximum Design Height (m)

Current Footprint (ha)

Final Design Footprint (ha)

Panda/ Koala/ Beartooth

Main Rock Pile (inactive) granite and surficial materials Stockpiles (inactive) topsoil, lake deposits, and glacial till Quarry (active) production of construction rock Landfill (active) inert landfill materials Zone S and Landfarm (active) hydrocarbon-impacted soil and rock

40 50 341 341

CKRSA (active) coarse processed kimberlite

30 50 115 115

Fox Main Rock Pile (inactive) granite, diabase, kimberlite rock Stockpile Area (inactive) topsoil Zone S (capped) hydrocarbon-impacted soil and rock

50 50 320 320

Sable South Pile (active) East Pile (future) West Pile (future) granite and diabase rock

23 (South) 0 (East) 0 (West)




Pigeon Main Rock Pile (active) mixed metasediment and granite rock Stockpile Area (inactive) till

34 (rock pile) 30 (till pile)




Misery Main Rock Pile (inactive, pending MUG Project approval) metasediment, granite, and diabase rock Landfill (capped) inert landfill materials Stockpiles (inactive) topsoil Zone S (inactive) hydrocarbon-impacted soil and rock

65 65 119 119

Lynx Main Rock Pile (active) granite and diabase rock and till

32 35 32 32

Jay Main Rock Pile (future) granite, diabase, metasediment, and till

0 65 0 227

WRSA = waste rock storage area; CKRSA = coarse kimberlite reject storage area; MUG = Misery Underground.



Table 5.5-2 Material Tonnage Waste Rock Storage Area Summary (through December 2017)

WRSA Total Surficial Material Granite Diabase Kimberlite Metasediment Mixed

Metasediment

Panda/Koala/ Beartooth 195.8 20.5 173.3 -- 1.8(a) 0.3(b) --

CKRSA 38.0 -- -- -- 38.0 -- --

Fox 148.8 7.2 110.6 2.8 28.2 -- --

Sable 3.2 0.3 2.9 -- -- -- --

Pigeon 31.6 4.4 -- -- -- -- 27.2

Misery 97.0 3.0 49.3 3.2 0.8(c) 40.7

Lynx 7.2 0.1 6.6 0.5 -- -- --

Jay -- -- -- -- -- -- --

Total 521.6 35.5 342.7 6.5 68.8 41.0 27.2

(a) Kimberlite mixed with granite waste rock at geological contact.

(b) Minor quantities of metasediment waste rock generated from Beartooth Pit.

(c) Kimberlite mixed with granite and metasediment waste rock at geological contact.

CKRSA = coarse kimberlite reject storage area.

Table 5.5-3 Estimated Future Waste Rock Tonnages for Planned Mining Activities (post-December 2017)

WRSA Total Surficial Material Granite Diabase Kimberlite Metasediment Mixed

Metasediment

Panda/Koala/Beartooth 0.1 -- 0.1 -- -- -- --

CKRSA 20.6 -- -- -- 20.6 -- --

Fox -- -- -- -- -- -- --

Sable 101.1 1.1 98.4 1.6 -- -- --

Pigeon 17.7 -- -- -- -- -- 17.7

Misery 0.6 -- 0.5 0.0(a) -- 0.1(b) --

Lynx 2.2 -- 2.0 0.2 -- -- --

Jay 154.8 7.7 101.1 14.0 -- 32.0 --

Total 293.8 8.8 202.0 15.8 20.6 32.1 17.7

(a) Small amount of 10,000 tonnes of diabase assumed to be generated from MUG Project.

(b) Small amount of 50,000 of metasediment assumed to be generated from MUG Project.

CKRSA = coarse kimberlite reject storage area; MUG = Misery Underground.



Panda/Koala/Beartooth Waste Rock Storage Area

The existing and final configurations of the Panda/Koala/Beartooth WRSA are provided on Map 5.5-2. The majority of the Panda/Koala/Beartooth WRSA is located within the Koala Watershed, with a small portion to the LLCF watershed. The underlying original ground contours indicate that drainage from the area now occupied by the WRSA was towards the west (now the LLCF area) and towards the east (now the Panda/Koala pit area). Waste materials from Panda, Koala, Koala North, and Beartooth open pits and the Panda and Koala underground developments are stored together in the WRSA close to the Ekati mine main camp. Waste rock deposition began in 1997 with the development of Panda Pit and deposited material quantities have totalled 195.8 million tonnes, and include 20.5 million tonnes of surficial materials from initial open-pit pre-stripping, 173.3 million tonnes of granite waste rock, and minor quantities of kimberlite and metasediment. Except for the minor incidental amounts of granite expected from underground development in the Koala Underground until it is closed in the latter part of 2018, the Panda/Koala/Beartooth WRSA is not expected to have future waste rock deposited. Therefore, it has likely reached its planned final design footprint, as deposition of waste rock is complete. The north side of the WRSA is currently being utilized as a quarry for construction materials.

Given the potential benefits for reclamation, surficial topsoil was salvaged (when operationally feasible) during the initial surficial stripping for the development of the Koala, Beartooth, and Pigeon pipes. Salvaged topsoil has been stockpiled at the northern and eastern end of the WRSA (Map 5.5-1). Lake deposits and glacial till materials were also segregated during the development of Panda/Koala North pits and stockpiled at the northern end of the WRSA. The soil stockpile locations are currently inactive; however, the Panda/Koala WRSA could be utilized for soil stockpiling of materials resulting from future Ekati mine developments.

This WRSA also contains the following management areas for landfill and hydrocarbon-impacted materials that are generated as part of ongoing Ekati mine operations.

• Landfill—The main camp solid waste landfill was commissioned in July 1998 and is located on the western side of the Panda/Koala/Beartooth WRSA (Map 5.5-1). The landfill is used for the disposal of inert non-hazardous wastes (e.g., metal, cement) generated as part of the operation of the mine.

• Zone S—Zone S is a management facility designed to accept hydrocarbon-impacted materials greater than 4 cm in diameter. Zone S locations accept large-diameter run-of-mine materials that were subject to spilled hydrocarbons. This waste stream is usually generated through the open-pit mining process when equipment failures cause spills of hydrocarbons that contaminate the blast rock as it is being excavated. Solid waste sewage is also deposited in Zone S of the Panda/Koala/Beartooth WRSA.

• Landfarm—The landfarm was constructed in 1998 and is a lined engineered facility designed with a leachate collection system and side berms to control runoff. The landfarm is used for the management of hydrocarbon-impacted soil generated at the mine site as a result of operational spills (e.g., diesel, glycol, gasoline, kerosene, jet fuels, hydraulic oil, transmission fluid, lube oil). Hydrocarbon-impacted soils with average particle sizes of less than 4 cm are bioremediated at the landfarm facility. The landfarm may also be used as secure temporary storage for hydrocarbon-impacted materials that are unsuitable for bioremediation, prior to these materials being sent off site for disposal.



Coarse Kimberlite Reject Storage Area

The existing and final configurations of the CKRSA are provided on Map 5.5-2. The CKRSA is predominantly located within the LLCF watershed, with a small portion on the southeast within the Koala watershed. The CKRSA has received CPK from the processing plant since 1998, with active placement ongoing. The CKRSA contains CPK from all pipes mined to date at the Ekati mine. CPK is crushed kimberlite rock with a grain size distribution of 0.5 to 25 mm in diameter. A total of 38 million tonnes of CPK has been deposited in the CKRSA, and an additional future 20.6 million tonnes are estimated until the end of 2035. The CKRSA has reached its current design footprint, and ongoing CPK is being vertically expanded from the current height of 30 m up to a final height of 50 m.

BEARTOOTHPIT LAKE

PANDA PIT LAKE

KOALA PIT LAKE

PELZERPOND

PANDALAKE

BEARCLAWLAKE

KODIAKLAKE

BUSTERLAKE

LONG LAKE

520000

7180

000

CRUSHER

LAYDOWNDEWATERING SUMPBURN PIT

KOALA PIT

MAIN CAMP

KOALANORTH PIT

PANDA PIT

BEARTOOTHPIT

PANDA DIVERSION CHANNEL

PELZERPOND

PANDALAKE

BEARCLAWLAKE

KODIAKLAKE

BUSTERLAKE

LONG LAKE

TEMPORARYLAYDOWN AREA

MIX OF SURFICIALMATERIAL AND GRANITEOVERLAIN BY GRANITE

GRANITE

TOPSOIL(UNDERLAINWITH ROCK)

ZONE STOPSOIL

LAKE BED SEDIMENTAND GLACIAL TILL

COARSE KIMBERLITEREJECT STORAGE AREA

LANDFARM

OPERATIONSLANDFILL

GRANITE

520000

7180

000

PAT

H: I

:\CLI

EN

TS\D

OM

INIO

N\1

7765

30\M

appi

ng\M

XD

\ICR

P\1

7765

30_M

ap5_

5-2_

Exi

stin

gFin

al_P

anda

Koa

laB

earto

oth_

WR

SA

.mxd

PR

INT

ED

ON

: 201

8-08

-13

AT: 1

:53:

28 P

M

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT

IMAGERY OBTAINED FROM CLIENT.PROJECTION: UTM ZONE 12 DATUM: NAD 83

PROJECT

EKATI MINE INTERIM CLOSURE AND RECLAMATION PLAN VER.3.0

TITLE

EXISTING AND FINAL CONDITIONS,PANDA/KOALA/BEARTOOTH WASTE ROCK STORAGE AREA

1776530 3000 0 5.5-2PROJECT NO. CONTROL REV.

LEGENDEXISTING EKATI MINE FOOTPRINT

COARSE KIMBERLITE REJECT STORAGE AREA

GRANITE

LAKE BED SEDIMENT AND GLACIAL TILL

LANDFARM

MIX OF SURFICIAL MATERIAL ANDGRANITE OVERLAIN BY GRANITE

OPERATIONS LANDFILL

TEMPORARY LAYDOWN AREA

TOPSOIL

ZONE S

END LAND USE TYPEBOULDER ASSOCIATION

OTHER RECLAIMED AREA

STABILIZED AREA

WATER

0 500 1,000

1:25,000 METRES

NOTE(S)

REFERENCE(S)

2018-08-13

MJ

AB

BW

LN

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED

EXISTING AND FUTURE CONDITIONS FINAL CONDITIONS

MAP



Fox Waste Rock Storage Area

The existing and final configurations of the Fox WRSA are provided on Map 5.5-3. The Fox WRSA is completely located with the Koala watershed. Waste rock deposition started in 2001 with the development of Fox Pit, and deposited material quantities have totalled 148.8 million tonnes and include 7.2 million tonnes of surficial materials from initial open-pit pre-stripping, 110.6 million tonnes of granite, 2.8 million tonnes of diabase, and 28.2 million tonnes of low-grade kimberlite. Toe berms to limit seepage flows to the receiving environment were constructed around a large portion of the WRSA perimeter. Topsoil from the perimeter of Fox Lake was salvaged during open-pit development for potential use in reclamation and has been stored north of Fox Pit (Map 5.5-3). During open-pit operations, the Fox WRSA had a Zone S where hydrocarbon-impacted soils and rock with average particle sizes of greater than 4 cm were managed. As part of the end of open-pit operations, the hydrocarbon-impacted materials deposited in Zone S were covered with granite.

The Fox WRSA is currently inactive, as Fox open-pit operations have ended. Underground mining is being evaluated for the Fox kimberlite pipe. Waste rock from underground development, if it were to occur, would likely be placed onto the Fox and/or Panda/Koala/Beartooth WRSAs. Similar to the MUG Project, it is expected that the amount of waste rock generated from underground mining at Fox Pit, if it were to occur in the future, could be accommodated within the existing footprint of the WRSA (i.e., no additional disturbances).

FOX PITLAKE

NEMA LAKE

NERO LAKE

MARTINE LAKE

FOX TWOLAKE

SIKSIK1

SIKSIK2

ONE HUMPLAKE

THREE HUMPLAKE

G05

LAKE C

LAKE E

POND D

NORA LAKE

SOUTH FOXLAKE 2

CLOSED / RECLAIMED FOX WASTE ROCK STORAGE AREA

514000 515000 516000 517000

7168

000

7169

000

7170

000

7171

000

FOX PIT

GLACIAL TILL

NEMA LAKE

NERO LAKE

MARTINE LAKE

FOX TWOLAKE

SIKSIK1

SIKSIK2

ONE HUMPLAKE

THREE HUMPLAKE

G05

LAKE C

LAKE E

POND D

NORA LAKE

SOUTH FOXLAKE 2

MIX OF KIMBERLITEAND GRANITE

OVERLAIN BY GRANITE

TOPSOIL

TOE BERM -LAKE BED

SEDIMENT ANDGLACIAL TILL

GRANITE

KIMBERLITE(EXPOSED AT SURFACE)

TOE BERM -LAKE BEDSEDIMENT ANDGLACIAL TILL

KIMBERLITE(OVERLAIN BY -10 M GRANITE)KIMBERLITE

ZONE S

514000 515000 516000 517000

7168

000

7169

000

7170

000

7171

000

PAT

H: I

:\CLI

EN

TS\D

OM

INIO

N\1

7765

30\M

appi

ng\M

XD

\ICR

P\1

7765

30_M

ap5_

5-3_

Exi

stin

gFin

al_F

ox_W

RS

A.m

xd P

RIN

TED

ON

: 201

8-08

-13

AT: 1

:47:

54 P

M

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT


PROJECT


TITLE

EXISTING AND FINAL CONDITIONS, FOX WASTE ROCKSTORAGE AREA



GRANITE

GRANITE COVER

KIMBERLITE

MIX OF KIMBERLITE AND GRANITE

TOE BERM - LAKE BED SEDIMENT AND GLACIAL TILL

TOPSOIL

ZONE S



STABILIZED AREA

WATER

0 500 1,000

1:20,000 METRES

NOTE(S)

REFERENCE(S)

2018-08-13

MJ

AB

BW

LN

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVEDMAP




Sable Waste Rock Storage Area

The existing and final configurations for the Sable WRSA are shown on Map 5.5-4. At completion, the Sable WRSA will consist of three areas, as shown on Map 5.5-4. The West WRSA is northwest of Sable Pit and the South WRSA is southwest of Sable Pit and wraps around the west side of Two-Rock Sedimentation Pond. The East WRSA is northeast of Sable Pit. The final design heights and footprints for the individual Sable WRSAs are provided in Table 5.5-1. The majority of the Sable WRSA is located within the Horseshoe watershed.

Construction of the Sable South WRSA started in late 2017, with a current height of 23 m and footprint disturbance of 93 ha. A total of 3.2 million tonnes of waste rock has been placed (0.3 million tonnes surficial material and 2.9 million tonnes of granite waste rock). An additional 101.1 million tonnes of material is estimated to be placed in the three Sable WRSAs until the planned end of Sable Pit operations in 2022. The deposited waste rock is estimated to be predominantly granite at 98.4 million tonnes, with minor amounts of surficial materials and diabase.

SABLE PIT LAKE

HORSESHOELAKE

ULULAKE

WEST WRSA

EAST WRSA

SOUTH WRSA

TWO ROCKLAKE

HORSESHOELAKE

ULULAKE

SOUTH WRSA

WEST WRSA (FUTURE)

EAST WRSA(FUTURE)

TWO ROCK DAMDEWATERING

ROAD/PIPELINE

TWO ROCKFILTER DIKE

INFRASTRUCTURE PAD

SITE HAUL ROAD

SABLE ROAD

SABLE PIT

WEST WRSA

PAT

H: I

:\CLI

EN

TS\D

OM

INIO

N\1

7765

30\M

appi

ng\M

XD

\ICR

P\1

7765

30_M

ap5_

5-4_

Exi

stin

gFin

al_S

able

_WR

SA

.mxd

PR

INTE

D O

N: 2

018-

08-1

4 AT

: 7:0

8:50

AM

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT


PROJECT


TITLE

EXISTING, FUTURE, AND FINAL CONDITIONS, SABLE WASTEROCK STORAGE AREA



FUTURE FOOTPRINT

DEWATERING ROAD / PIPELINE

INFRASTRUCTURE PAD

ROAD

TWO ROCK DAM

TWO ROCK FILTER DIKE




WATER0 500 1,000

1:15,000 METRES

NOTE(S)

REFERENCE(S)

2018-08-14

MJ

AB

BW

LN

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVEDMAP




Pigeon Waste Rock Storage Area

The existing and final configurations for the Pigeon WRSA are shown on Map 5.5-5. The Pigeon WRSA is located completely within the LLCF watershed boundaries. The Pigeon WRSA began receiving waste rock with the development of Pigeon Pit in 2014. A total of 27.2 million tonnes of mixed metasediment has been placed into the Pigeon WRSA and an additional 17.7 million tonnes is estimated to be placed until the end of planned Pigeon Pit operations in 2021. The WRSA has reached its final footprint and is currently at a height of 34 m with a final maximum design height of 70 m. Glacial till mined from Pigeon Pit has been stockpiled adjacent to the WRSA for potential future use in reclamation, and when mixed with waste rock, deposited within the WRSA. No more till is estimated to be generated from Pigeon Pit, and hence the till pile has reached its design footprint and height of 30 m.

LITTLEREYNOLDS POND

PIGEONPIT LAKE

7180

000

PIGEONPIT

LITTLEREYNOLDS POND

PIGEONMIXED METASEDIMENT AND GRANITE

TILLSTOCKPILE

DISTURBEDAREA

DISTURBED AREADISTURBED

AREA

SABLE ROAD

7180

000

PAT

H: I

:\CLI

EN

TS\D

OM

INIO

N\1

7765

30\M

appi

ng\M

XD

\ICR

P\1

7765

30_M

ap5_

5-5_

Exi

stin

gFin

al_P

igeo

n_W

RS

A.m

xd P

RIN

TED

ON

: 201

8-08

-14

AT: 7

:19:

30 A

M

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT


PROJECT


TITLE

EXISTING AND FINAL CONDITIONS, PIGEON WASTE ROCKSTORAGE AREA

1776530 3000 0 5.5-5PROJECT NO. CONTROL REV. MAP


MIXED METASEDIMENT AND GRANITE

TILL STOCKPILE



STABILIZED AREA

WATER

0 200 400

1:10,000 METRES

NOTE(S)

REFERENCE(S)

2018-08-14

MJ

AB

BW

LN

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED




Misery Waste Rock Storage Area

The existing and final configurations of the Misery WRSA are shown on Map 5.5-6. Original ground contours underlying the WRSA lie in the King Pond and Cujo Lake drainages to the northeast, Lac de Gras drainage to the southeast, and Carrie Pond drainage to the southwest. Waste rock deposition was initiated in 1999 with the development of Misery Pit. Waste rock deposition was stopped in 2005 and resumed in 2012 when the Misery Pit pushback was initiated.

The Misery WRSA is constructed to encapsulate internal layers of metasediment within a 5 m thick cover of non-PAG rock (granite and diabase). Metasediment and granite/diabase have been placed in alternating layers 10 m thick and 5 m thick, respectively. Deposited material quantities have totalled 97 million tonnes and include 3.0 million tonnes of surficial materials from initial open-pit pre-stripping, 49.3 million tonnes of granite waste rock, 40.7 million tonnes of metasediment waste rock, and 3.0 million tonnes of diabase waste rock. Northeast of the Misery WRSA is a topsoil storage area (Map 5.5-6), where material stripped from Misery Pit and construction of the King Pond Dam is stored for possible future reclamation use.

Recently, the WRSA has stopped receiving waste rock as a result of the end of open-pit operations. The Misery WRSA will also receive a small amount of waste rock (approximated to equal 0.6 million tonnes) from the development of the MUG Project, which is planned to occur until 2022. The additional waste rock from MUG mining will not result in additional footprint disturbance as it will be placed on the final 515 m lift of the Misery WRSA 65 m above the natural tundra elevation.

Additionally, the following material management areas for landfill and hydrocarbon-impacted materials are outlined:

• Landfill—A landfill at the Misery site (Map 5.5-6) was commissioned in August 2001 and was located north of Misery Pit within the footprint of the Misery WRSA. When mining was suspended at Misery in 2005, the landfill was reclaimed (covered with granite).

• Zone S—The Misery WRSA also has a Zone S (Map 5.5-6) where hydrocarbon-impacted soils and rock with average particle sizes of greater than 4 cm become part of the waste rock pile.

Lynx Waste Rock Storage Area

The existing and final configurations of the Lynx WRSA are shown on Map 5.5-6. The original ground contours underlying the WRSA lie in the Carrie Pond drainage to the southeast, the Mossing Lake drainage to the south, and the Cujo Lake drainage to the north and east. Deposition of waste rock started in 2015 with the development of Lynx Pit. The Lynx WRSA is currently active, with a total of 7.2 million tonnes deposited consisting of 0.1 million tonnes of surficial materials, 6.6 million tonnes of granite, and 0.5 million tonnes of diabase. An additional 2.2 million tonnes (2 million tonnes of granite and 0.2 million tonnes of diabase) is estimated to be generated from Lynx Pit until early 2019. Waste rock from the Lynx Pit not used for construction purposes at the Ekati mine will be placed on the Lynx WRSA. The current configuration of the WRSA has reached its maximum disturbance footprint with a current height of 32 m.

MISERY PIT LAKE

MIST LAKE

CARRIE PONDMOSSING LAKE

CUJO LAKE

THINNERLAKE

KING POND

540000

7160

000

MISERY PIT

KING PONDSETTLING FACILITY

MIST LAKE

CARRIE PONDMOSSING LAKE

CUJO LAKE

THINNERLAKE

ZONE S

LYNXWASTE ROCK STORAGE AREA

CRUSHER PAD

ALTERNATING LAYERS OF PAGAND NON-PAG ROCK

TOPSOIL

LANDFILL (WITHGRANITE COVER)

540000

7160

000

PAT

H: I

:\CLI

EN

TS\D

OM

INIO

N\1

7765

30\M

appi

ng\M

XD

\ICR

P\1

7765

30_M

ap5_

5-6_

Exi

stin

gFin

al_L

ynxM

iser

y_W

RS

A.m

xd P

RIN

TED

ON

: 201

8-08

-14

AT: 7

:17:

34 A

M

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT


PROJECT


TITLE

EXISTING, FUTURE AND FINAL CONDITIONS,LYNX ANDMISERY WASTE ROCK STORAGE AREA



FUTURE FOOTPRINT

ALTERNATING LAYERS OF PAGAND NON-PAG ROCK; KIMBERLITE STOCKPILE

LANDFILL WITH GRANITE COVER

TOPSOIL


ZONE S



STABILIZED AREA

WATER

0 250 500

1:20,000 METRES

NOTE(S)

REFERENCE(S)

2018-08-14

MJ

AB

BW

LN

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVEDMAP




Jay Waste Rock Storage Area

The planned final configuration of the Jay WRSA is shown on Map 5.5-7. Construction of the Jay WRSA has not yet started. As per the project schedule shown in Chapter 8, Jay WRSA construction is expected to start in 2023 with Jay Pit operations. The Jay WRSA is located with the Lac du Sauvage watershed. A total of 154.8 million tonnes of waste rock is planned to be placed over the life of Jay Pit. The main waste materials will be surficial materials (7.7 million tonnes of lake bottom sediments), granite/diabase (115.1 million tonnes), and metasediment (32 million tonnes). The waste rock will be co-placed in a manner that achieves a pre-defined ARD characterization criterion (such as neutralization potential / acid potential [NP/AP] ratio) as determined through the Jay waste rock co-placement study design (Part H, Condition 4 of the Water Licence). It is planned that selective stockpiling of till surficial soils from Jay Pit development will be completed for future potential reclamation use and the remaining surficial materials will be placed within the Jay WRSA in specified locations.

LAC DU SAUVAGE

540000

7165

000

NORTH DIKE

LAC DU SAUVAGE

PROPOSED JAY WASTE ROCK STORAGE AREA

540000

7165

000

PAT

H: I

:\CLI

EN

TS\D

OM

INIO

N\1

7765

30\M

appi

ng\M

XD

\ICR

P\1

7765

30_M

ap5_

5-7_

Exi

stin

gFin

al_J

ay_W

RS

A.m

xd P

RIN

TED

ON

: 201

8-08

-13

AT: 1

:51:

21 P

M

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT


PROJECT


TITLE

EXISTING, FUTURE AND FINAL CONDITIONS, JAY WASTE ROCKSTORAGE AREA


LEGEND


FUTURE FOOTPRINT

END LAND USE TYPE

BOULDER ASSOCIATION

OTHER RECLAIMED AREA0 400 800

1:15,000 METRES

NOTE(S)

REFERENCE(S)

2018-08-13

MJ

AB

BW

LN

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVEDMAP




5.5.1.3. Waste Rock Storage Area Material Geochemical Characterization

At closure, WRSA seepage water quality must meet established closure water quality criteria before being considered safe for entry to the environment. Waste rock geochemical characterization is a fundamental consideration in actions required to achieve the closure seepage water quality objectives (Section 5.5.2.1). The geochemical baseline report prepared for the Jay Project provides a detailed interpretation of the Ekati mine geochemical characterization dataset (DDEC 2014a). The geochemical characteristics of Ekati mine rock are also described and updated periodically in the WROMP (Dominion 2018b). Waste rock geochemical characterizations are verified during mining operations through regular sampling of waste rock as it is mined according to protocols described in the WROMP.

In the letter of decision regarding Version 9 of the WROMP and Sable WRSA Design Report Version 2.0, the WLWB included Decision #3, which requested further clarification of the methods for calculating neutralization potential (NP) results and associated NP/AP ratios. In response, Dominion submitted a memo titled Investigation of Effective Neutralization Potential of Waste Rock at the Ekati Mine (Golder 2018c).

A summary of the WRSA material tonnage through December of 2017 is provided in Table 5.5-2. The primary waste rock material deposited in the WRSAs is granite, equating to 66% of the total tonnes deposited. Metasediment waste rock and waste kimberlite are secondary waste materials, accounting for 13% of the total tonnage deposited. Surficial materials (7%) and diabase (1%) both represent minor material quantities. The following subsections summarize the geochemical characteristics of each waste rock type in the Ekati mine WRSAs.

Granite and Diabase

In general, granite and diabase are physically competent and are used as general construction materials. Granite is the least physically and chemically reactive waste rock type at the Ekati mine. Granite generally consists of felsic, silicate minerals including quartz, plagioclase, feldspar, muscovite, biotite, chlorite, kaolinite/illite, and ilmenite, with trace carbonate, epidote, magnetite, and apatite. Minerals present in metasedimentary rock include quartz, chlorite, amphibole, phlogopite, illite, feldspar, calcite, dolomite, siderite, and kaolinite. Diabase consists of feldspar and pyroxene, with minor chlorite, clay, quartz, and clays. Sulphide minerals (pyrite with lesser pyrrhotite and chalcopyrite) are present in trace quantities in both granite and diabase.

As outlined in the WROMP (Dominion 2018b), over 1,100 samples of granite have undergone geochemical testing. The average total sulphur content of granite is low (0.03%); 85% of the granite dataset contains less than 0.05% sulphur. The bulk NP of granite samples ranges from 0.8 to 331 kilograms of calcium carbonate equivalent per tonne of material (kg CaCO3/t; 470 samples), with a median of 5.0 kg CaCO3/t and average of 8.9 kg CaCO3/t. Owing to the low sulphide mineral content of granite, it is unlikely that oxidation of sulphide minerals will result in acid generation.

The results of geochemical testing of over 160 samples of diabase confirmed that diabase also has a low potential for acid generation. One sample of diabase in the dataset underwent mineralogical testing, in which only silicate minerals were identified (plagioclase feldspar, augite, illite, ilmenite, kaolinite, phlogopite, and quartz). Diabase samples have a low total sulphur content, with an average of 0.13%. The NP of diabase ranges from 0.5 to 68 kg/t CaCO3, with an average value of 13 kg/t CaCO3 and a median value of 11 kg/t CaCO3.

Granite and diabase have a low potential to generate acidity, owing to their low sulphide content, and are classified as non-PAG. The results of long-term leach testing (i.e., humidity cell testing) presented in the Jay DAR (DDEC 2014a) confirm that granite has a low acid generation potential and a low metal leaching potential. Diabase humidity cell testing (HCT) also confirmed that diabase, in general, has a low acid generation potential. One sample of diabase collected from Fox Pit contained sulphide mineralization, and generated weakly acidic leachate during the test period. As discussed in the WROMP (Dominion 2018b), this sample was only mildly reactive and did not generate appreciable acidity.



Metasediment

All metasediment is conservatively managed as PAG, as a practical field method to effectively differentiate PAG from non-PAG metasediment has not been developed. Minerals present in metasedimentary rock include quartz, chlorite, amphibole, phlogopite, illite, feldspar, calcite, dolomite, siderite, and kaolinite, with trace pyrite and pyrrhotite. Metasediment samples have an average sulphur content of 0.1%, and NP varies between 0.1 to 406 kg/t CaCO3 (average 17 kg/t CaCO3 and median 9 kg/t CaCO3). Approximately 45% of the samples in the metasediment dataset are classified as PAG. The results of HCT confirm that metasediment containing sulphide mineralization is capable of generating acidity and leaching sulphate and metals in low pH conditions.

Kimberlite

Kimberlite is not used as a general construction material because it is a relatively weak material. Total sulphur concentrations in kimberlite range from <0.005% to 1.9% (median 0.26%), but NP varies between 2.5 and 465 kg/t CaCO3. Kimberlite is classified as non-PAG, owing to the presence of sufficient NP to neutralize the acidity that could be generated by sulphide oxidation. The results of humidity cell testing confirm that kimberlite has a low acid generation potential but could leach some metals in neutral conditions (DDEC 2014a).

Surficial Materials

A number of overburden samples from the Ekati mine have undergone geochemical testing. Overall, overburden has a low acid generation potential, owing to low sulphur content (<0.005% to 0.93%) and presence of sufficient NP to neutralize the acidity that could be generated by sulphide oxidation (DDEC 2014a).


The fundamental closure objectives for the WRSAs are to ensure that the seepage water quality is safe, they are physically stable, and they are safe for wildlife movement through the reclaimed site. The overall closure approach for the WRSAs has been developed through a number of reports and studies, beginning with the original EAs, as part of ICRP Version 2.4 (BHP Billiton 2011a), and through annual closure and reclamation progress reports. Recently, the development of the WRSA closure risk assessment framework has played a key role in furthering the selection of appropriate actions to ensure safe seepage water quality.

Based on the closure goals and principles for the Ekati mine ICRP, five closure objectives have been identified specifically for the closure and reclamation of the WRSAs. The objectives and criteria of the ICRP relating specifically to reclamation of WRSAs are presented in Table 5.5-4. Table 5.5-4 also presents the general reclamation actions and the monitoring associated with achievement of the closure objectives.

Table 5.5-4 Closure Objectives and Criteria for Waste Rock Storage Areas


WR-1 Seepage water quality is safe for entry to the Receiving Environment.

Either mix geochemically reactive materials with non-reactive materials or cap with non-reactive materials to the degree needed to meet water quality criteria. Remediate hydrocarbon-impacted materials in the Landfarm and Zone S areas or cap with non-reactive materials.

Seepage water quality complies with closure water quality criteria. Material is placed in accordance with approved design.

Routine seepage water quality monitoring Thermal instrumentation monitoring of WRSAs containing metasediment materials and potential waste kimberlite



ID Objective Action Criteria Measurement/Monitoring WR-2 Erodible waste material is

physically stable. Cover erodible materials with competent material, or vegetate or otherwise stabilize them.

Erosion of WRSA surface is similar to comparable natural surfaces in the area.


WR-3 WRSA side slopes are physically stable.

Build the WRSA as designed. Design configuration is as documented in the WRSA Design Report.


WR-4 Landfill materials are isolated from the environment.

Cover landfill materials with competent material or otherwise isolate them.

Material is placed in accordance with approved design.


WR-5 WRSAs are safe for wildlife.

Develop WRSA-specific closure designs in the context of site-wide wildlife movement.

Design configuration is as documented in WRSA-specific design.

Physical inspection by a qualified professional Routine monitoring of wildlife during closure

WRSA = waste rock storage area.


Dominion has engaged with the TKEG and community groups on the topic of wildlife safety and WRSAs through a number of means, including TKEG meetings, workshops in Yellowknife, and community visits (Appendix C). Through this engagement, Dominion has sought to answer general questions and hear concerns regarding wildlife safety, but has also sought input and feedback on specific questions.

Community input received during these sessions has been recorded and reviewed. There is a clear lack of overall consensus on whether ramps should be constructed on the WRSAs. Considerations from community and TKEG engagement for the building of access ramps are that the ramps would allow caribou (and other wildlife) to travel over the WRSAs and would provide access to the top of the piles for insect and heat relief. Conversely, considerations for not building ramps have included that the ramps could trap caribou on the pile and provide easy access for predators (such as wolves) and that caribou could get lost on the top of the WRSA. Some noted that the waste rock piles would be too tall for caribou to use, or that caribou would be unlikely to travel to the top of piles in the absence of a food source or mating opportunities and in the presence of other animals.

During the 27–28 February 2018 workshop in Yellowknife, community members were also interested to know if uranium had been encountered in the mining process, and how uranium concentrations in the WRSAs would be monitored and managed. There was also extensive discussion of the NP of the waste rock piles and the ability to neutralize acidity from the oxidation of minerals. Concern was raised about the potential for runoff and dust from the WRSAs to contaminate the land, water, and wildlife in the watershed, and it was suggested that dikes or berms should be used for containment purposes. Contamination of the groundwater column beneath each of the waste rock piles and pile freezing and erosion were also identified as areas of concern.

Community visits in mid-2018 yielded further feedback on the WRSA piles. Many noted the sensitivity of caribou to large cobbles and boulders, and the potential for very coarse substrate on the piles to result in potential for injury. A common suggestion was to ensure that a fine-grained material be used to cover the waste rock storage piles to avoid this potential. It was also recommended that ramps be of an appropriate slope to allow caribou easy access on and off of piles. Some expressed concern that the risks to caribou on the waste rock storage piles would be too high, even with mitigation, and suggested that access to the piles be restricted. Others suggested that caribou may avoid the piles in the absence of a food source or mating opportunities, and considering that they have been observed to avoid walking on bare rock. The size and imposition of the piles on the landscape was also raised.



Information obtained through engagement, along with broader site-wide and regional information as referenced in Section 5.2, has been used to inform the evaluation of options outlined in Section 5.5.4.3.


The overall closure approach for the WRSAs has been developed and established through a number of reports and studies, beginning with the original EAs, as part of ICRP Version 2.4 (BHP Billiton 2011a), and through annual closure and reclamation progress reports. In particular for the WRSAs, the design for operations has considered closure and reclamation of the WRSAs for physical stability and seepage water quality at closure. As such, the closure designs of the WRSAs are carried forward from the options assessed and approved through the construction and operations design process and are embedded within the base closure plan. However, key areas where closure options evaluation are ongoing are the appropriate cover approach for the Pigeon WRSA, the approach to the stabilization of waste kimberlite, and the approach for safe wildlife movement for all WRSAs. Principal considerations related to these aspects are outlined below under the relevant objective for the particular option being evaluated.

5.5.4.1. Pigeon Waste Rock Storage Area Seepage Water Quality (WR-1)

The mixed materials mined from Pigeon Pit could be classified as non-PAG based on the pre-mining and ongoing geochemical testing for the Pigeon site. A closure cover was initially proposed as additional mitigation to address the uncertainty associated with pre-mining testing of drill core samples. A closure cover design for the Pigeon WRSA was outlined in Tetra Tech (2017), which was included in Appendix C of Version 7.0 of the WROMP. The proposed Pigeon WRSA cover was designed to achieve the same results as the cover at the Misery WRSA (i.e., to encapsulate PAG rock such that seepage water quality at closure would comply with closure water quality criteria). The Pigeon WRSA cover design proposed in Version 7.0 of the WROMP consisted of a 2.4 m thick layer of stockpiled glacial till overlain by a 1.8 m thick layer of non-PAG rock (granite and diabase). The WRSA side slopes would be smoothed to a degree that enables efficient and safe placement of the till layer. The design made beneficial use of an unusually large quantity of glacial till that was locally stockpiled. This use of till material reduced the quantity of non-PAG rock that would otherwise have to be excavated and hauled from the Panda/Koala/Beartooth WRSA. As a result of the stakeholder review and overall comments and recommendations, the WLWB did not approve the final cover design and indicated that the design should be determined through the overall closure planning process. A draft modification of the initially proposed cover design has been developed and is being considered by Dominion. Operations at Pigeon Pit have been underway since 2016, and to date, the results of operational monitoring of as-mined waste rock verify that the mixed rock being placed into the Pigeon WRSA can be classified as non-PAG. Elders interviewed for the What’aa- Esker Research Project expressed the importance of clean water to Tłı̨chǫ and recommended “designs for waste rock piles must include safeguards against potential water contamination” (Chocolate 2015: 4). The Elders recommended that the location of waste pock piles should be selected away from waterbodies as this would help provide filtration of any acidic water or metals from the piles. However, Elders also noted that eskers near waterbodies better support wildlife and that the benefits and risk of these two factors should be considered (Chocolate 2015).

Further operational monitoring and incorporation of the Pigeon WRSA into the Waste Rock Storage Area Closure Risk Assessment Framework (WRAF), which includes thermal and seepage modelling and risk assessment, will enable a final determination on the need for and design of a closure cover.



5.5.4.2. Physical Stabilization of Waste Kimberlite Materials (WR-2)

Previous research trials conducted from 2008 (Dominion 2018e, Appendix F) suggested that newly placed waste kimberlite may not be a preferred growth medium due to insufficient water holding capacity. Based on these findings, a competent rock cover has been proposed as the means for physically stabilizing CPK at the CKRSA and exposed waste kimberlite at the Fox WRSA. The ongoing successful Cell B LLCF research results of vegetation growth on FPK has resulted in a revaluation of whether vegetation can be utilized to physically stabilize waste kimberlite materials at the CKRSA and Fox WRSA. Reclamation research is proposed to evaluate various vegetation options on the CKRSA, including the use of stockpiled till and/or lakebed sediment materials as amendments to increase water holding capacities.

5.5.4.3. Wildlife Safety (WR-5)

To address wildlife safety, ICRP Version 2.4 (BHP Billiton 2011a) proposed the inclusion of access ramps for caribou (and other wildlife). Recent engagement with the TKEG and community groups revealed a clear lack of overall consensus on whether ramps should be constructed on the WRSAs (see Section 5.5.3). Some have suggested that ramps of suitable slope and substrate size (i.e., small grain) could allow access to and from the roads, while others have suggested that the roads would not be suitable movement corridors and should be removed altogether. Tłı̨chǫ Elders interviewed for the What’aa Esker Research Project recommended planning and building waste rock piles in a manner that encouraged the diversion of caribou away from roads to help minimize collisions (Chocolate 2015). In addition, feedback and TK received in relation to the open-pit mine works (Section 5.3.3), in many cases, carries over into the approach to wildlife safety taken with regard to the WRSAs.

The development of the closure design elements needed to ensure WRSAs are safe for wildlife movement is ongoing. As part of this work, an evaluation of each WRSA has been undertaken to determine how each WRSA fits into site-wide wildlife movement. Table 5.5-5 outlines a preliminary evaluation of WRSAs, taking into account recent and historical movement patterns of caribou in the area (i.e., regional and site-wide), habitat types surrounding the WRSA, and proximity to other adjacent movement corridors (e.g., roads that will be reclaimed). Map 5.5-8 and Appendix G illustrate habitat types in order of preference (high to low) for facilitating caribou movement, the projected post-closure habitat types for the WRSAs, and other reclaimed facilities. Habitat types identified as more conducive to facilitating caribou movement include esker complex and lichen veneer, heath tundra, low shrub communities, and tussock/hummock/graminoid tundra habitat types. Boulder association, bedrock association, heath/bedrock, and heath/boulder are land cover types with difficult terrain that caribou tend to avoid. These areas generally do not facilitate caribou movement and should be avoided when identifying potential access/egress points. This is corroborated by TK, which indicates that caribou select travel corridors partly for comfortable footing and that they (and the Tłı̨chǫ) prefer sandy or smooth materials rather than larger substrate size material types (e.g., boulders) (Chocolate 2015). Tłı̨chǫ Elders have also expressed concern that rough terrain, boulders, and rocky piles could injure caribou (Chocolate 2015): “To prevent injury to caribou the Tłı̨chǫ Elders suggested either building the rock piles lower or filling in the spaces between rocks. Adding a sandy surface was also recommended” (Chocolate 2015).

WRSA-specific decision-making regarding the need to facilitate wildlife access/egress and the number and location of access points will be advanced through reclamation research (see Section 5.5.9), ongoing engagement with communities and TK holders (see Section 2.4), and future updates to the ICRP. Once these initial decisions are made, other more detailed design aspects will be considered, such as optimizing use of existing haul road access ramps and the optimal slope and grain size that will allow safe use by wildlife. A proposed final design for each WRSA will be submitted to the WLWB for review and approval prior to undertaking final closure activities.

HHHHHHHH

HHHHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHH HHHHHHHHHHH

HH

HHH

HHHHH

HHHHH

H HHHHHHH

HHHH

HHHH

HHH

HHHHHHHHH

HHHHHHHHHH

HHHHHHH H

HHHHH

HHH

HHH

HH

HHHH

HHH

HH HHHHH

HH

HHHH

HHHHHHHHH

HHHHH

HHHH

HH

HHHHHHHHHHHHHH

HHHHHH

HHH

HHHH HHH

H HHHHHH

HHHHHH

H

HHHHHHH

HHHH

HHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHH

HHHHH

HHHH

HHHH

H

HHH

HH

HHHHHHHH

HHHH

HHH

HHHHH

HH

HH

HHHHHHHHHHH

HHHHHHHHHHHHHHH

HHHHHHH

HH

HHHHHHHHHHHHHH

HHHHHHHHHH HH HHHH

HHHHHHHH

HHHH

HH

HHHH

HHH

HHHHHHHHHHH

HHH

H HHHHHHHHH HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHH

H HHH

HHHHHHH H

HHHHHHHHHHHHH

HHHHHHHHH

HHHHHHHH

HHHHH

HHHH HHHH

HHHHH

HHHHHHHHH

HHHH

HHHHH

HHHHHHHH

HHHHHH HHH

HHHH

HHHHHHHHHHH

HHHHHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHH

HHHHHHH

HHHH

HHH

HHHHHHHHHHH

HHHHHHHHHHHHH HHH

HH

HHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHH

!.

!.!.

!.

!.

!.

!.

!.!.

!.

!.!.!.

!.

!.

!.

!.

!.

!.

!.

!.!.!.

!.

!.!.

!.!.!.

!.

!.

JAY WRSA

MISERY WRSALYNX WRSA

LAC DUSAUVAGE

KODIAKLAKE

G05LAKE

LAKE E

LLCFCell E

LLCFCells A/B/C

SABLEPIT LAKE

FOXWRSA

LONG LAKECONTAINMENT

FACILITY

PIGEONPIT LAKE

BEARTOOTHPIT LAKE

PANDAPIT LAKE

MAINCAMP

KOALAPIT LAKE

AIRSTRIP

LYNXPIT LAKE

MISERYPIT LAKE

MISERY ROAD

KOALANORTH

PIT LAKE

PIGEON WRSA

FOXPIT LAKE

WESTWRSA

SOUTHWRSA

LLCFCell D

PATH

: T:\0

1-pr

ojec

ts\E

kati\

Pro

ject

_MX

D\E

KA

-23-

320e

.mxd

PR

INTE

D O

N: 2

018-

08-1

3 AT

: 3:3

3:25

PM

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT

WEST KITIKMEOT / SLAVE STUDY - VEGETATION CLASSIFICATION MOSAIC

PROJECTION: UTM ZONE 12 DATUM: NAD 83

PROJECT


SITE-WIDE CARIBOU MOVEMENT

02111136-2015 #### 0 MAP 5.5-8PROJECT NO. CONTROL REV. FIGURE

0 2 4

Kilometers1:150,000 METRES

LEGEND

HHHHHHEsker

Previous Jay Pit Area

!. Caribou Crossing Ramp

NOTE(S)

REFERENCE(S)

2018-08-13

MS

MS

JR

LN

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED

Re c l a i me d Fe a t ur e

ESKER COMPLEX Misery Road, Lynx Road, Sect ion of Sable Road.

LICHEN VENEER

HEATH TUNDRA (<30% Rock)

TUSSOCK/ HUMMOCK LLCF Cells A, B and C.

WETLAND (SEDGE MEADOW)

TALL SHRUB

PEAT BOG

BIRCH SEEP

HEATH/ BOULDER(30-80% Boulders)HEATH/ BEDROCK(30-80% Bedrock)

Main Camp, Airst r ip, Inf rast ruct ure Pad, Laydown Area

BEDROCK ASSOCIATION(>80% Bedrock)

REVEGETATED

BOULDER ASSOCIATION(>80% Boulders)

Pigeon, Panda-Koala -Beart oot h , Fox, West , Sout h, Lynx, Jay and Misery WRSAs, minor sit e roads, sect ion of Sable Road, sect ion of Misery Road, Jay Dyke and t he airst r ip.

SPRUCE FOREST

SHALLOW WATER (> 2m Deep)

ICE AND SNOW

DEEP WATER (< 2m Deep)Pigeon, Koala, Panda, Beart oot h, Fox, Koala Nort h, Sable, Misery, Lynx, Jay Pit Lakes, Two Rock Sediment at ion Pond, LLCF Cell D, LLCF Cell E and sect ions of Jay Sit e and Road.

La nd C l a ssi f i c a t i on Da t a

Land Classification Data in table are listed in order from highest to lowest qualityin terms of facilitating caribou movement.



Table 5.5-5 Evaluation of Waste Rock Storage Areas for Facilitating Wildlife Use and Movement

WRSA Considerations

Priority Legend High Medium Low Panda/Koala/Beartooth The WRSA itself will represent a large area (341 ha) of low quality boulder association habitat. At 1 km wide and 3 km

long, it would be a barrier to movement, even if some access/egress ramps were built into the closure design. TK shared through community engagement and workshops suggests that even with the installation of access/egress ramps, caribou may not travel onto waste rock storage piles in the absence of a food source or mating opportunities. The WRSA is surrounded by habitat and terrain that will not facilitate safe movement of caribou. To the south and east, movement would be limited by the deep water of the Panda/Koala and Beartooth pit lakes, and farther south, there is substantial heath/bedrock and heath/boulder habitat, which is unlikely to be used by caribou. The reclaimed LLCF, immediately to the west of the WRSA, is anticipated to provide for ease of movement given its flat and vegetated terrain. The use of the site may increase after reclamation given its location adjacent to higher value habitats to the north and east. The WEMP and collar data show low movement and use of this area due to rugged terrain, and it is considered low priority for facilitating access/egress.

Fox The WRSA itself will represent a large area (320 ha; 2 km wide) of low quality boulder association habitat and would be a barrier to movement, even if some access/egress ramps were built into the design. TK shared through community engagement and workshops suggests that even with the installation of access/egress ramps, caribou may not travel onto waste rock storage piles in the absence of a food source or mating opportunities. The haul road ramps connecting from the pit up onto the piles would not be easily accessed by wildlife, nor would they represent good escape routes. TK shared through community engagement and workshops suggests that the using fine-grained material on access/egress ramps associated with the road at known caribou crossing locations could enhance the use of the roads as migration routes. The WRSA is surrounded by low quality heath/bedrock and heath/boulder habitat, which is unlikely to be used by caribou. The WEMP and collar data show low movement and use of this area due to the rugged terrain, and it is considered low priority for facilitating access/egress.

Sable TK information, WEMP, and collar data all indicate higher caribou use in the Sable area than other areas of the Ekati mine. The haul road ramps onto the West and South WRSAs will be located in the area between Sable Pit Lake and the Two-Rock Sedimentation Pond. This area would not be easily accessed by wildlife, nor would it represent a good escape route. TK shared through community engagement and workshops suggests that the using fine-grained material on access/egress ramps associated with the road at known caribou crossing locations could enhance the use of the roads as migration routes. Movement is potentially impeded to the north of the WRSA due to poorer quality habitat in these areas, which limits opportunities for safe access/egress. There is good quality tundra habitat to the east and south of the WRSAs and a west–east trending esker complex is evident south of the WRSA. Reclamation efforts will continue to evaluate options, including encouraging movement around the eastern and southern sides of the Sable WRSA (i.e., along roads reclaimed to esker complex habitat). Final closure design will take this evaluation into account.

Pigeon The WRSA itself is small (66 ha) relative to other WRSAs at the Ekati mine, presenting less of a barrier to movement, and it is surrounded by relatively good quality tundra habitat. The revegetated LLCF to the south and west will be dry, flat, and stable, facilitating caribou movement. A west–east trending esker complex is evident north of the WRSA. TK information, WEMP, and collar data all indicate higher caribou use in the area between Pigeon and Sable. The Pigeon area routinely attracts animals for feeding. TK information also indicates a movement corridor trending southwest-northeast, keeping to the southern shore of Upper Exeter Lake, and away from the boulder fields that are further south. Mining is planned to be complete at Pigeon Pit in 2021. Monitoring of wildlife activity in this area after cessation of mining activity will be particularly valuable to support ongoing closure planning (see Section 5.5.6).



Misery/Lynx The WRSAs are surrounded by relatively good tundra habitat, although the area immediately to the south and east of the WRSAs has poorer habitat, and the combination of deep water from Misery Pit Lake, Mist Lake, and King Pond would affect movement options. The shape/orientation of the Misery WRSA is parallel to the dominate direction of travel, making it less likely to act as a barrier to movement. The road from Lynx Pit and ramp to the Lynx WRSA may facilitate movement. TK shared through community engagement and workshops suggests that the using fine-grained material on access/egress ramps associated with the road at known caribou crossing locations could enhance the use of the roads as migration routes. The existing haul road ramp at the south end of the Misery WRSA would not be easily accessed by wildlife; in order for it to function as an escape route, it would need to connect with the road/esker network. There is a north–south trending esker between Misery/Lynx WRSA and Jay WRSA, and the Narrows (identified by TK as an important area) are located to the east. Reclamation efforts that focus on encouraging movement toward and through these areas (e.g., road reclamation to esker) may be more appropriate for ensuring safety and providing benefits of heat and bug relief than access/egress on the Misery/Lynx WRSAs.

Jay Compared to the other WRSAs, the Jay WRSA will be surrounded by a mosaic of cover types, including wetland, boulder, and deep water. The WRSA itself will represent a large area (227 ha) of low quality habitat and would be a barrier to movement, even if some access/egress ramps were built into the design. The east side of the WRSA is immediately adjacent to Lac du Sauvage, which would constrain opportunities for access and egress in that direction. There is a north–south trending esker between Misery/Lynx WRSA and Jay WRSA, and the Narrows (identified by TK as an important area) are located to the south and east. Reclamation efforts that focus on encouraging movement toward and through these areas (e.g., road reclamation to esker) may be more appropriate for ensuring safety and providing benefits of heat and bug relief than access/egress on the Jay WRSA.

WRSA = waste rock storage area; TK = Traditional Knowledge; LLCF = Long Lake Containment Facility; Narrows = Lac du Sauvage – Lac de Gras

Narrows; WEMP = Wildlife Effects Monitoring Program.



The general steps in the closure for the WRSAs include the following:

• Complete waste rock placement as per WLWB-approved design and prepare final WRSA as-built construction drawings.

• Construct ramps or similar structures to permit access and egress from target WRSAs, or push waste rock onto haul road access ramps to reduce or prevent access; the final locations, size, optimal slope and grain size, number of ramps, and considerations around blocking accesss will be determined through futher research and engagement as decribed in Section 5.5.3.3.

• WRSAs will be built as per approved designs to provide adequate slope stability. At Pigeon WRSA, some additional smoothing of slopes may be required to facilitate cover placement, depending on the final cover design.

• For residual till and topsoil stockpile areas that will remain in place (i.e., that may not be used in the implementation of other site closure activities) scarify and seed as required, and flatten any slopes that are overly steep.

• Phsyically stabilize exposed waste kimberlite materials at the CKRSA and Fox WRSA by either placing a rock cover or though vegetation if deemed feasible through reclamation research.

• Cover Zone S hydrocarbon-impacted rock storage sites with granite/diabase rock.

• Physically stabilize residual remediated hydocarbon-impacted soil (if present) by scarifying and seeding as required.



Based on the geochemical characterizations (Section 5.5.1.3), no specific additional WRSA seepage management strategies for non-PAG granite, diabase, and kimberlite waste rock materials are required. For the Misery, Pigeon, and Jay WRSAs, where PAG metasediment may be present, special design and construction methods have been applied for the purpose of mitigating the risk of poor quality seepage from the metasediment contained within the WRSA. The methods are summarized as follows:

• Misery WRSA—Layered construction augmented by a closure cover of granite/diabase rock was selected for the Misery WRSA to mitigate ARD risk. The design consists of alternating layers of potentially reactive metasediments (10 m thick) with non-reactive granite and diabase (5 m thick) and placement of a final cap of 5 m of non-PAG material. The alternating layers provide internal ARD risk mitigation and the closure cover physically separates the PAG rock from the surface environment. The thickness of the closure cover (5 m) provides additional risk mitigation by containing the seasonal active layer and, thereby, reducing thaw and surficial runoff through the underlying PAG rock.

• Pigeon WRSA—It is planned that future predictive modelling, risk assessment, and evaluation of the results of operational monitoring will enable a final determination of the need for and design of a closure cover at the Pigeon WRSA (see Section 5.5.4.1 for more information).

• Jay WRSA—The Jay WRSA is designed to achieve and maintain an overall non-PAG characterization throughout the WRSA by co-placement of PAG and non-PAG rock within an internal co-placement zone according to operating procedures which will be determined through the results of the Jay co-placement study. In this way, effective ARD mitigation will have been achieved during mine operations. The relative quantities and scheduling of PAG (i.e., metasediments) and non-PAG rock (i.e., non-reactive granite and diabase) excavated from Jay Pit are such that there is a “surplus” of non-PAG rock to be excavated during the last years of open-pit operations. The surplus quantity of non-PAG rock is adequate to provide a 5 m thick closure cover, which would serve as additional ARD mitigation in the same manner as at the Misery WRSA.


Information collection and development has been carried out and will continue to be carried out in support of the engineering works for the selected closure activities; this includes TK and community engagement, modelling and seepage risk assessment, thermal modelling, and slope stability evaluations. Key aspects are summarized below.

Fox Waste Rock Storage Area Drilling Investigation

Preliminary thermal modelling results were completed for the Fox WRSA, and the results indicated that there are unique factors affecting freezing in the Fox rock piles, and that these factors require further development before predictive modelling can be completed. To investigate the potential factors affecting the freezing of the Fox WRSA, Dominion completed a permafrost and geochemical drilling investigation program at the Fox WRSA in 2015. The drilling investigation was conducted between 8 and 20 June 2015. The drilling setup included a track rig for drill string and tools and a core shack next to the drill rig (Photo 5.5.1).

The program included the completion of six boreholes that were logged to provide depth to bedrock, general lithology and geochemical information, and condition of the overburden and bedrock. Selective soil and rock samples were collected throughout the drilling process for further laboratory testing. Installed instrumentation included six ground temperature cables and three piezometers to measure the water level. The geochemical results of the drilling investigation are outlined in Golder (2016c) and the permafrost/geotechnical results in Tetra Tech EBA (2016). The collected data were utilized in the development of the thermal modelling and water balance components of the WRAF for the Fox WRSA (see Section 5.5.5.2.2).



Photo 5.5-1 2015 Fox Waste Rock Storage Area Drilling Investigation

Misery Waste Rock Storage Area Drilling

A winter drilling investigation program was completed at the Misery WRSA in 2018 (Photo 5.5-2). One drill hole was advanced into the Misery WRSA in February and March 2018. Samples were collected for geochemical and mineralogical analysis, and the drill hole was instrumented to monitor ground temperature, moisture content, and porewater chemistry. The results of the investigation will supplement existing geochemical and geotechnical information for the Misery WRSA, and will be used to further develop the understanding of the geochemical reactivity and thermal profile within the Misery WRSA.

Photo 5.5-2 2018 Misery Waste Rock Storage Area Drilling Investigation



Waste Rock Storage Area Closure Risk Assessment Framework

The WRAF was developed as a means of better understanding and discussing the long term closure ecological risks related to WRSAs through integrated thermal, water balance, and water quality modelling. In October 2016, the WRAF was developed for the Panda/Koala/Beartooth WRSA, CKSA, Fox WRSA, and Misery WRSA as these were the WRSAs that had an operational seepage monitoring dataset suitable for use in the models. The developed WRAF consisted of the following three submissions:

• WRSA thermal modelling (Tetra Tech EBA 2016)—Thermal models were developed that predicted the rate of permafrost development within the WRSA for the closure period.

• WRSA seepage water quality modelling (Golder 2016c)—Calibrated water quality models were developed for each WRSA to estimate seepage water quality during the remaining years of operations and into closure.

• WRSA seepage risk assessment (ERM 2016b)—An ecological risk assessment was developed for the closure period. The thermal and water quality modelling results fed into the completion of this component.

A summary of the WRAF predictive thermal modelling results is provided in Table 5.5-6; this table also includes a summary of the thermal modelling efforts completed for the Pigeon, Sable, and Jay WRSA design reports. The climate change approach used in support of the thermal modelling is described in Section 5.5.5.2.4. Table 5.5-7 provides an overall summary of the WRAF seepage modelling and the ecological risk assessment. The WRAF submissions have undergone an extensive stakeholder engagement and review process.

Topics raised and recommended by stakeholders for further evaluation in the review of the WRAF submissions have been included as part of Dominion’s proposed reclamation research plans (Appendix E) for addressing uncertainties with WRSAs containing metasediment and kimberlite materials (see Section 5.5.6 for more information). Additionally, it is intended that the WRAF will be utilized as part of the determination of the need and design of closure cover for the Pigeon WRSA (see Section 5.5.3 for more information).

Table 5.5-6 Waste Rock Storage Area Predictive Thermal Modelling

WRSA and Modelling Reference Model Results Summary

Pigeon WRSA Pigeon Waste Rock Storage Area Design Report (Tetra Tech EBA 2014a) provided in WROMP Version 4.0 update, and updated modelling reported in Tetra Tech (2017), provided in WROMP Version 7.1

The WRSA is estimated to freeze back in eight years without the effects of internal heat generation due to sulphur oxidation. Adding internal heat generation extends the freeze-back process to 12 years. The modelling includes climate change projections.

Panda/Koala/Beartooth Closure Risk Assessment Framework (Tetra Tech EBA 2016)

The waste rock below the active layer in the central area of the Panda/Koala WRSA is predicted to remain frozen (around -2°C or colder) for at least 100 years (the reasonable extent for modelling predictions) under the climate change scenario modelled.

CKRSA Closure Risk Assessment Framework (Tetra Tech EBA 2016)

Thermal predictions indicate that the warmest area of the CKRSA will freeze 17 years after placement. CPK below the active layer is predicted to remain frozen for at least 100 years (the reasonable extent for modelling predictions) under the climate change scenario modelled.

Misery WRSA Closure Risk Assessment Framework (Tetra Tech EBA 2016)

Newly placed waste granite below the active layer is predicted to gradually freeze back and become completely frozen approximately 12 years after placement. The predicted long-term temperatures indicate that the waste rock below the active layer is predicted to remain frozen after 100 years (the reasonable extent for modelling predictions) under the climate change scenario modelled.

Fox WRSA Closure Risk Assessment Framework (Tetra Tech EBA 2016)

The results for the long-term performance prediction of the Fox WRSA indicate that the ground temperature will slowly cool to a frozen condition. This is primarily due to the material properties (high moisture content and clay content) present within the kimberlite layers of the WRSA. A time period ranging from 58 to 65 years is predicted under the climate change scenario. The long-term thermal analysis results for the Fox WRSA indicates that the waste rock below the active layer will remain frozen after 100 years (the reasonable extent for modelling predictions) under the climate change scenario modelled.




Jay WRSA Design Report Jay Project Water Licence Amendment Application (Golder 2017)

Model results indicate that for average temperature conditions, the foundation of the WRSA will be frozen by the end of the mine life, but most of the waste rock will still be thawed. The facility will freeze back progressively over time. The climate change models show that, in general, temperatures in the WRSA will continue to decrease until about 50 to 70 years after closure. After that, due to the increasing warming effect of air temperatures, the upper 20 m of the pile showed a trend of increasing temperatures, but temperatures in the lower portions of the pile, near the foundation and within the foundation, continued to decrease for the post-closure 100-year period that was modelled.

Sable WRSA Design Report Sable WRSA Design Report (Tetra Tech 2018) provided in WROMP Version 9.0 update

The South WRSA will be in a frozen condition after five years from initial placement, and the West WRSA will be in a frozen condition after three years from initial placement. The maximum seasonal thaw depths at the South and West WRSAs were estimated to be approximately 4.8 m and 5.6 m 100 years after construction under mean climate condition and the modelled climate change scenario, respectively. Both the South and West WRSAs will stay in a frozen condition 100 years after construction under the worst case climate scenario modelled.

WRSA = waste rock storage area; WROMP = Waste Rock and Ore Storage Management Plan; CKRSA = coarse kimberlite reject storage area; CPK =

coarse processed kimberlite.

Table 5.5-7 Summary of Waste Rock Storage Area Closure Seepage Water Quality and Ecological Risk Assessment

Closure Seepage Modelling (a)

Seepage water balance and water quality models were developed using GoldSim™ Version 11.1. GoldSim is a graphical, object-oriented mathematical modelling program where all input parameters and functions are defined by the user and are built as individual objects or elements linked together by mathematical expressions. The water balance model accounts for seepage, precipitation and snowmelt, runoff, and delays to flow as water moves through each flow path of a conceptual seepage flow model. Water quality predictions were derived by adding chemical loads to developed water balance flow data. Loading rates were derived first using HCT results for the different waste rock types at the Ekati mine (i.e., granite, diabase, metasediment, and kimberlite). The lab-based loading rates were calibrated using seepage flow and chemistry data collected at the different WRSAs during the bi-annual site inspections. Sensitivity analysis of the water flow balance water model was completed by considering high seepage and low infiltration scenarios. Additionally, a sensitivity analysis was run to simulate the effect of different closure cover thicknesses. Cover thicknesses of 5 m granite/diabase (per the Misery WRSA design) and 1 m (for physical stabilization) were simulated.

Closure Ecological Risk Assessment (b)

The overall purpose of this WRSA seepage screening level risk assessment was to determine the potential for unacceptable health risks to aquatic life and terrestrial wildlife due to exposure to seepage from the Fox, Misery, Panda/Koala/Beartooth, and CKRSA WRSAs during closure conditions. This ecological risk assessment integrated the results of the baseline water quality data, modelled closure water quality data in seeps and receiving waterbodies, wildlife receptor characteristics, and toxicity reference values into a risk characterization for aquatic and terrestrial organisms. The risk assessment conservatively considered the high seepage scenarios and a 1 m physical stabilization cover for kimberlite materials at the Fox WRSA and CKRSA and a 5 m ARD mitigation cover for metasediment materials at the Misery WRSA. Based on the calculated hazard quotients for aquatic life, predicted closure conditions do not pose a risk to aquatic life at the Ekati mine site. Sulphate concentrations in CKRSA seepage exceed the sulphate wildlife toxicity reference values (based on livestock guidelines) and indicate risk to mammalian and avian receptors based on the calculated hazard quotient for sulphate. However, the limited data available on sulphate toxicity to livestock (used as a surrogate for wildlife), particularly the more recent and relevant studies, do not suggest that effects on growth, reproduction, or survival will occur at the sulphate concentrations predicted in the CKRSA seepage.

(a) Golder 2016c.

(b) ERM 2016b.

WRSA = waste rock storage area; HCT = humidity cell test; CKRSA = coarse kimberlite reject storage area; ARD = acid rock drainage.

Climate Change

The thermal modelling that was conducted as part of the WRAF included consideration of climate change. The Ekati mine is located within the climate zone of continuous permafrost, and there have been observed changes in air temperature over time at Yellowknife and Contwoyto Lake/Lupin meteorological stations (EBA 2006b).



Given the recent history of changes in air temperature, and the potential for future climate change, the potential effects of climate change on the closure of the Ekati mine have been evaluated through the numerical modelling of climate scenarios.

There is no single system to be used for climate change predictions in northern Canada. Past study has shown that model predictions are variable both with respect to temperature and precipitation (Prowse et al. 2009a,b,c). As a result, various modelling scenarios have been considered for predictive modelling at the Ekati mine. The selection of modelling scenarios and approaches has been based on the relevant research at the time of the work and professional judgement, and has evolved over time.

The current approach for climate change that will be used for work going forward is the approach that was used for the recent thermal modelling for the expansion of the Pigeon WRSA. In developing this approach, the following updated climate change scenarios that are applicable to the Ekati mine area were reviewed:

• the Coupled Model Intercomparison Project Phase 5 (CMIP5) from the website of Canadian Climate Data and Scenarios (Government of Canada 2018)

• the SNAP (Scenarios Network for Alaska + Arctic Planning) climate change scenarios (tool developed by the University of Alaska Fairbanks) from the website of Environment and Natural Resources, Government of Northwest Territories (GNWT-ENR 2018)

Based on this review, the CMIP5 Representative Concentration Pathway (RCP) 4.5 (intermediate GHG emissions) was adopted, as it was considered a conservative model for thermal predictions compared to the SNAP scenarios considered and A1B of Canadian the Standards Association (CSA 2010), and was an intermediate scenario between RCP2.6 (low) and RCP8.5 (high).

Moving forward, Dominion will continue to evaluate climate predictions for the Ekati mine area and incorporate into thermal modelling as appropriate. It is anticipated that the assumptions and data used in the modelling will be updated in the next ICRP update.

Slope Stability

Slope stability numerical modelling is used to demonstrate that closure WRSA designs will be stable for closure conditions. A summary of completed WRSA closure slope stability analyses is provided in Table 5.5-8. Physical stability assessments and designs for the Panda/Koala/Beartooth and Fox WRSAs were conducted internally during early years of Ekati mine operations, and as a result, are not referenced to individual engineering assessments in Table 5.5-8. These WRSAs are complete (excluding the CKRSA) and have been stable in operation.

Table 5.5-8 Waste Rock Storage Area Slope Stability Analysis Summary


Misery WRSA 515 m Expansion Appendix E of 2016 WROMP Version 6.2 Update

In general, the factor of safety is relatively high for any deep-seated multi-bench failure. Good overall stability can be attributed to a shallow overall slope angle and the frozen core within the WRSA infrastructure. Therefore, adding a 15 m layer expansion on the top of the WRSA does not seem to impact the overall stability of the infrastructure. On the other hand, surficial and shallow circular failure has a relatively lower but still acceptable factor of safety, similar to that of 2014 stability evaluation outcome.




Pigeon WRSA Pigeon WRSA Design Report (Tetra Tech 2017) provided as part of WROMP Version 7.0 update

The proposed design of the Pigeon WRSA meets the stability requirements during construction, post-construction stage before closure cover placement, and long-term closure after closure cover placement, as documented in Tetra Tech 2017.

Sable WRSA Design Report Sable WRSA Design Report (Tetra Tech 2018) provided in WROMP Version 9.0 update

The proposed design of the Sable WRSA meets the stability requirements during construction and post-construction stage

Jay WRSA Design Report Jay Project Water Licence Application (Golder 2017)

The results of the long-term stability assessment indicate that the minimum factor of safety requirements are met for the Jay WRSA for thawed and frozen conditions. Conservative ranges of material strength parameters were evaluated, and calculated factor of safety values are well above the design criteria. The design includes a general thickness of 2 m of granite basal layer which is increased to a thickness of 4 m over the lakebed sediments such that short-term stability factor of safety requirements are met. Dominion will carry out a site investigation before construction of the Jay WRSA to confirm the foundation conditions, particularly the presence or absence of ice-rich soils.

WRSA = waste rock storage area; WROMP = Waste Rock and Ore Storage Management Plan.


Waste Rock Seepage Quality (WR-1)

The overall objective is to ensure that seepage water quality is safe for entry to the Receiving Environment. Seepage water quality in closure will need to meet established closure water quality criteria. Based on the results of thermal monitoring and modelling, it is expected that the WRSAs will freeze and remain frozen over the long term. Freezing of the WRSAs is considered beneficial for safe water quality; however, permanently frozen conditions throughout the WRSAs is not necessary for achieving the closure objective. Therefore, freezing of the WRSAs is not a closure objective with corresponding thermal criteria for achievement. Closure criteria for seepage water quality will be developed prior to closure taking into account operational monitoring data, updated design, and modelling.

WRSA designs are established through operational approvals of the WROMP and WRSA design reports, where required. Seepage quality is a key consideration in the design of all the WRSAs with the following general design considerations being employed:

• WRSA design attempts to limit, to a reasonable degree, the number of affected watersheds and to favour placement of waste rock within drainage areas that already include mine facilities or activities, including minewater management facilities. For example, the location and footprint of the Pigeon WRSA were selected to be within the LLCF drainage area and to not expand into the Upper Exeter Lake drainage.

• WRSAs are designed with consideration of setback distances from local waterbodies and, where necessary, other natural features of the landscape. Setback distance from waterbodies will generally be designed to provide adequate physical space for implementation of adaptive management responses (if necessary) based on site-specific conditions. Setback distance will be considered for other natural features that are of special or unique importance, such as eskers. For example, design of the Jay WRSA provides for 200 m setback from the local esker, which was identified through community engagement and TK as being of special importance.



• WRSA design incorporates a basal layer of non-reactive construction rock over the tundra prior to construction of the lifts. This allows early aggradation of permafrost into the base of the WRSA and limits contact of waste rock with the tundra soils, which can be naturally acidic.

• Where PAG rock is present or anticipated, the need for specific design measures to mitigate the risk of ARD is considered and appropriate design approaches are developed to accommodate site-specfic conditions. The Misery, Pigeon, and Jay WRSAs demonstrate site-specific approaches to ARD risk mitigation.

Hydrocarbon-Impacted Materials (WR-1)

Hydrocarbon-impacted materials at the Ekati mine will be removed, covered, or remediated prior to site closure. These materials are managed under the Hydrocarbon-Impacted Material Management Plan, which is a component of the Waste Management Plan. The Waste Management Plan is a requirement of the Water Licence and has been approved by the WLWB.

As part of closure activities, environmental site assessments will be conducted to determine the type and extent of contaminated soils. Where contaminated soils are identified, remediation efforts will be undertaken as needed to achieve the objectives. Hydrocarbon management of excavated materials will be required at the Landfarm and Zone S:

• The Landfarm (hydrocarbon-impacted soil and rock less than 4 cm) will be remediated in situ or disposed of off site at the end of closure activities. Remediated soil may be used for site reclamation work, and all residual remediated soil in the Landfarm will be physically stablized as required.

• Zone S at the Panda/Koala/Beartooth and Misery WRSAs (hydrocarbon-impacted rock and soil greater than 4 cm) that are not already covered will be covered with non-PAG material at closure.

Erosion Physical Stability (WR-2)

Due to their overall grain size and potential for weathering, surficial and kimberlite materials represent a potential risk of erosion. A summary of the current locations of kimberlite and surficial materials that could be susceptible to erosion is as follows:

• Kimberlite—CKRSA and low-grade kimberlite stockpiles located at the Fox WRSA (see Map 5.5-3).

• Surfical soils—Soil stockpiles located at the Panda/Kola/Beartooth, Fox, Misery, Pigeon, and Jay WRSAs.

Stockpiled soil (topsoil, till) and lakebed sediment is planned to be used to enhance vegetation efforts at the Ekati mine. Any stockpiled materials that are not used for reclamation will be stabilized using a vegetation cover. Stockpile revegetation that has already been completed at the Ekati mine is described in Table 5.5-9.

Reclamation research completed on waste kimberlite has indicated that waste kimberlite may not be an effective growth medium and will require a non-PAG rock cover for erosion physical stability (Dominion 2018b). That being said, the successful establishment of vegetation on FPK in Cell B of the LLCF indicates that vegetation growth could be possible on waste kimberlite materials. Physical stabilization of waste kimberlite materials is being evaluated as a closure option with reclamation research (see Sections 5.5.4.2 and 5.5.6 for more information).



Table 5.5-9 Stockpile Additives and Revegetation to Date

Stockpile Additives and Revegetation Completed to Date

Panda / Koala Topsoil Storage Area North of Panda / Koala / Beartooth WRSA Topsoil / lakebed sediment / glacial till

• sewage sludge • 16-16-16 NPK fertilizer at 200 kg/ha • aerially seeded at 25 kg/ha

Beartooth Topsoil Storage Area North of Panda / Koala / Beartooth WRSA Topsoil

• 16-16-16 NPK fertilizer at 150 kg/ha • aerially seeded at 35 kg/ha

Fox Topsoil Storage Area North of Fox Pit Topsoil

• 16-16-16 NPK fertilizer at 150 kg/ha • scarified and aerially seeded at 35 kg/ha

Misery Topsoil Storage Area East side of Misery WRSA Topsoil mixed with glacial till

• 16-16-16 NPK fertilizer at 200 kg/ha • seeded at 25 kg/ha


Slope Physical Stability (WR-3)

The slope stability of deposited material is a key consideration of the initial design of the WRSAs. The WRSAs have been designed with long-term stability in mind, such that once the WRSAs are built as designed, it is expected that they will meet all applicable criteria for long-term stability in post-closure. Section 5.5.5.2.5 provides a summary of the current status of the stability assessments for each WRSA.

A summary of the typical design criteria in place to ensure physical stability of deposited WRSA materials is provided in Table 5.5-10. The criteria outlined in Table 5.5-10 are general criteria, and specific slope stability criteria are developed for each WRSA based on specific site conditions and material types.

In selected areas of the site, till stockpiles are present, such as the glacial till in the Pigeon WRSA. The above general criteria are not applicable to till materials, which will have considerably flatter angles of repose. For till stockpiles that are not used during the implementation of closure and reclamation activities, final slopes that provide acceptable stability will flatter than those of waste rock.

Table 5.5-10 General Slope Design Waste Rock Storage Area Criteria of Waste Rock Storage Areas

Design Parameter Unit General Criteria

Ramp gradient % 8 to 10

Ramp width m 30 to 32

Angle of repose degrees 35 to 37

Lift heights m Variable, typically 10 to 20

Maximum overall height above underlying tundra m Target 50

Overall slope angle degrees Variable, typically 18 to 28

Landfill Material Isolation (WR-4)

As per the Ekati mine Waste Management Plan, only inert solid materials are deposited in the current operations landfill and are planned for the demolition landfill. As per operational waste management record keeping and reclamation research, these materials would not be expected to have any potential effects on the receiving environment.



Dominion proposed a change from a permafrost encapsulation for landfill materials to physical stabilization to prevent wind and water erosion and to promote wildlife and human safety. Landfill materials will not include hazardous wastes or other reactive materials. As part of the 12 June 2015 WLWB reasons for decisions on the 2014 annual progress report, the WLWB indicated that “the Board has approved the requested change in closure objective for the operation and demolition landfills and requires DDEC to place a 2 m cover on both landfills to address stability concerns (Decision #6)” (WLWB 2015). Dominion will therefore place a 2 m cover that consists of a 1 m lift of waste kimberlite for physical isolation, followed by a 1 m lift of non-PAG waste rock over the landfilled material, providing a cover with a total of 2 m of non-reactive material over the landfill waste.


Engineering designs for WRSA closure have been completed for all facilities (with the exception of the Pigeon WRSA). Small refinements of the designs may occur over the operating life of the mine. Reclamation uncertainties are specific reclamation items that require addressing through reclamation research. Three reclamation uncertainties and a summary of how they will be addressed through reclamation research plans and monitoring are provided in Table 5.5-11. The referenced research plans are provided in Appendix E.

Table 5.5-11 Waste Rock Storage Area Closure Uncertainties


Wildlife safety on and around WRSA in closure RP 1 – Wildlife Safety

What type of cover, if any, is required for closure of the Pigeon WRSA to achieve reclamation objectives for the Ekati mine

RP 4 – Pigeon Waste Rock Storage Area Closure Cover

Seepage from exposed kimberlite at the Fox WRSA and the CKRSA RP 5 – Waste Kimberlite Seepage

Method for determining net neutralization potential for Jay WRSA RP 6 – Jay Waste Rock Storage Area Co-placement

Whether vegetation can be used to physical stabilize exposed waste kimberlite waste rock at the Fox WRSA and on CPK at the CKRSA

RP 7 – Kimberlite Waste Rock and Coarse Processed Kimberlite Vegetation Physical Stabilization

WRSA = waste rock storage area; RP = research plan; CKRSA = coarse kimberlite storage area; CPK = coarse processed kimberlite.


The post-closure monitoring program for the WRSA mine component will be adapted from existing monitoring programs at the Ekati mine, including waste rock seepage monitoring, geotechnical stability inspections, and the WEMP. Monitoring of each indicator will continue until closure objectives are achieved. The indicators selected for monitoring of the WRSA mine component to establish when closure objectives have been met are listed in Table 5.5-4.

In addition to the seepage water quality monitoring objective, at the end of operations, it is planned that that thermal instrumentation will be installed within WRSAs that contain metasediment materials (Misery, Pigeon, and Jay WRSAs). Thermal data will be used to provide further documentation of mechanisms that are protective of closure water quality. Based on the overall reclamation research results for water from the WRSAs that contain waste kimberlite (Fox and CKRSA), thermal instrumentation no future instrumentation is currently planned for these WRSAs, but may be considered in the future. At this time, it is not planned to install any thermal instrumentation at the end of operations in WRSAs containing non-reactive granite, diabase, and surficial materials (Lynx and Sable WRSAs).



As part of the selection of the overall preferred closure option for Pigeon WRSA (see Section 5.5.4.1), monitoring is expected to be required as part of any cover design. The cover would be designed for physical stability, considering the geotechnical properties of the available cover materials. Regular visual inspection of the cover would be required to confirm that it is performing as designed. This inspection will include checking the cover for evidence of slumps, cracks, excessive erosion, or signs of processes such as solifluction that could impact the cover integrity. At a preliminary level, it has been assumed that his will be an annual inspection after spring freshet, with additional inspections scheduled if needed due to an extreme precipitation event.

At the completion of all closure works for each WRSA, a survey will be conducted to document the as-built conditions of the WSRA, including final slopes, footprints, volumes, and heights. The results will be used as part of the documentation demonstrating that the facility has been built in accordance with the final design intent and approved closure design, for documentation in the performance assessment report.


Potential negative residual effects that may remain in the WRSAs mine component after successful reclamation and closure work has been completed are summarized in Table 5.5-13.

Table 5.5-12 Predicted Residual Effects


• WRSAs will remain over 1,414 ha of the site. WRSAs will range in height from 50 to 70 m above the surrounding ground surface. A permanent visual effect on the landscape will remain from the presence of WRSAs. WRSAs were designed to balance the effects of the height of the WRSA versus the footprint.

• The permanent visual effect may affect use of the land for traditional activities, such as hunting and fishing.

• The WRSAs will represent a permanent modification of the terrestrial habitat. Land use by wildlife within the footprint of the WRSAs and the growth and type of vegetation will be different than in pre-mining conditions. However, the WRSAs will designed and closed to be safe for wildlife at closure and will consider site-wide wildlife movement (especially caribou) through the reclaimed mine site, as well as habitat use of reclaimed areas.

• Seepage from the WRSAs represents a change in hydrology and water quality. WRSAs are built and will be closed to mitigate the risk of poor quality seepage and are closely monitored to determine potential for adverse effects.



Contingency measures that are associated with identified residual risks are summarized in Table 5.5-14. Monitoring programs currently in place and described in Section 5.5-7 will detect potential undesirable physical and environmental changes caused by waste rock storage. If this occurs, the likely causes will be determined and management plans will be revisited. The general strategy to address residual risks has three steps:

1. Confirm the effect through monitoring, sampling, and data analysis.

2. Investigate the cause through research.

3. Implement mitigation measures.



The process underlying this strategy is founded on an adaptive management approach that is iterative based on monitoring results, research findings, and changes to leading practice and regulation. The adaptive management approach provides opportunities to test, monitor, and adapt reclamation strategies where required based on the circumstances and conditions.

Table 5.5-13 Key Residual Risks and Contingencies for Waste Rock Storage Areas


Poorer than anticipated seepage quality from WRSA • Monitor and test water quality; update or conduct predictive modelling; develop mitigative or remedial options if necessary

Slope failure on stockpiles • Inspect, redesign, mitigate, and monitor

Wildlife safety is adversely affected by WRSA • Monitor wildlife usage • Design and implement mitigation plans to better accommodate wildlife safety


5.6. Processed Kimberlite Containment Areas

There is currently one active PKCA for deposition of PK at the Ekati mine: the LLCF (Table 5.6-1). The Phase 1 PKCA was part of the original kimberlite bulk sample processing conducted at Old Camp and has not been in operation since 2002. The area has since undergone progressive reclamation (see Chapter 6).

In addition to active deposition in the LLCF, PK can also be deposited and stored in open pits. Mining at Beartooth Pit was completed in April 2009, and beginning in 2013, FPK was deposited into the pit via the Beartooth FPK slurry pipeline (Section 5.3.1.2.1). Beartooth Pit continues to operate as a PKCA and water management facility. The mined-out Panda and Koala pits are planned for PK deposition beginning in 2019 after the completion of mining and decommissioning activities in the Koala Underground (Chapter 8).

This section focuses on closure and reclamation of the LLCF. A description of the storage of PK in the open pits (Beartooth Pit and Panda and Koala pits) and the associated closure activities is provided in Section 5.3.

Details regarding the composition of the PK (including the geochemical characterization) is provided in the Wastewater and Processed Kimberlite Management Plan (DDEC 2017l).

Table 5.6-1 Processed Kimberlite Containment Areas and Associated Infrastructure

PKCA Infrastructure Status

LLCF Cells A, B, C, D, and E Dikes B, C and D Outlet Dam Pumps, pipelines, and access roads

Active deposition

PKCA = Processed Kimberlite Containment Area; LLCF = Long Lake Containment Facility.

5.6.1. Long Lake Containment Facility Component Description

A comprehensive discussion of baseline site conditions (equivalent to pre-disturbance conditions) is provided in Chapter 3 of this document. Aspects of the pre-disturbance, existing, and final conditions specifically applicable to the LLCF are summarized below.




The pre-disturbance area of the LLCF encompassed Long Lake (a large, deep lake) in addition to Nancy Lake, Brandy Lake, and Willy Lake. The latter three lakes were the headwater lakes within the Long Lake drainage basin. Long Lake was the headwater of the western Koala watershed, which feeds into the Lac de Gras watershed. Down gradient of the LLCF in the Koala watershed are Leslie Lake, Moose Lake, Nero Lake, Nema Lake, Martine Lake, and Slipper Lake. Prior to development of the LLCF, Long Lake encompassed an area of approximately 614 ha.

Table 5.6-2 summarizes the pre-development physical characteristics of the lakes encompassed by the LLCF, as described in the 1995 EIS (BHP and Dia Met 1995).

Table 5.6-2 Physical Characteristics of the Pre-disturbance Long Lake Containment Facility

Lake

Maximum Breadth (m)

Length (m)

Max Depth (m)

Mean Depth (m)

Lake Area (ha)

Watershed Area (ha)

Volume (m3)

Average Discharge (million m3/yr)

Long 729 8,430 32 7.4 614.4 4,400 45,000,000 8.0

Nancy 300 710 5 1.1 14.2 - 125,813 -

Brandy 950 450 - - 29.9 - - -

Willy 380 850 9 4.1 23.9 - 986,351 -

Source: BHP and Dia Met 1995.

- = data not available.

Pre-operational hydrology, water quality, and biological setting of the LLCF is available in the 1995 EIS (BHP and Dia Met 1995).

Typical of most headwaters, pre-disturbance water quality in the lakes in the Long Lake drainage basin (Long Lake, Nancy Lake, Brandy Lake, and Willy Lake) were characterized as soft, of low ionic strength, and circumneutral pH. The lakes were chemically homogeneous prior to development. The Long Lake basin is located on Precambrian Shield; therefore, water runoff that accumulated Long Lake basin lakes contained few particulates or dissolved components. The fish species found in the lakes in the Long Lake basin were lake trout, round whitefish, Arctic grayling, and burbot. More information on the fish species of the lakes in the Ekati claim block is provided in Section 3.5.3.

The Long Lake basin is characterized by predominant heath mat tundra ecosystem which occurs on moderately well-drained upland sites. The vegetation is typically a well-developed mat of low shrubs including dwarf birch, willow, and Labrador tea. Frost boil areas are typical throughout the watershed, with areas of boulders and rock slopes. In sheltered pockets along the eastern perimeter of the watershed, tall shrub communities dominated by willow have developed.


The LLCF has been in operation since 1998 and was designed to safely contain PK and to provide acceptable water quality and quantity according to operating and environmental protection requirements. PK is separated at the processing plant and the fine fraction (defined as material less than 0.5 mm in diameter, classed as fine sand, silt, and clay) is sent to the LLCF as a slurry by pipeline. The components of the LLCF include containment Cells A, B, C, D, and E; filter Dikes B, C, and D; the Outlet Dam; water pumps; access roads; and pipelines, spigots, and power lines. Cell E is used as a final polishing pond where water quality can be monitored and water levels can be controlled. During operations, the Discharge of Cell E water is controlled by the Outlet Dam, a frozen core dam. Water is only discharged to the downstream Receiving Environment when it meets the water quality requirements specified in the current Water Licence (W2012L2-001).



Table 5.6-3 Description and Current (2017) Status of Long Lake Containment Facility Components

Component Status

Cells Cells A and C currently receive and store PK and minewater. Cell B is no longer receiving PK, and LLCF cover reclamation research is currently underway in the northern end of Cell B (see Section 5.6.5.2). Cell D is licensed to store PK, but no deposition has occurred to date; instead, Cell D is used as a minewater management and reclaim water pond. Cell D will serve as a contingency PK deposition area throughout mine operations. Cell E provides surge water storage capacity for surplus water and acts as a finishing pond prior to pumping and discharging into the Receiving Environment. Cell E will not receive PK.

Dikes The letter designation of each of Dikes B, C, and D corresponds to upstream subtended cell. These filter dikes are designed to retain PK solids within the upstream cell but allow water to filter through to the downstream cell. Dike B is considered to be effectively sealed (as anticipated) and water transfer from Cell B to C flows through a culvert. Dike C is considered to be partially sealed, and water transfer from Cell C to D is augmented by pumping. Dike D is not affected by PK, but water transfer from Cell D to E is augmented by pumping as required to safely manage pond water levels.

Outlet Dam The Outlet Dam serves as the downstream water control structure which retains water until sampled, authorized, and pumped to the Receiving Environment. Water levels are maintained with minimum 1.0 m freeboard and in accordance with the current Water Licence.

Water pumps Pumps on the upstream side of Dike C are used to pump water from Cell C to the reclaim barge in Cell D. The reclaim water barge in Cell D pumps water to the processing plant. In 2017, a weir was installed on Dike D to control the flow of water from Cell D to Cell E (this has replaced a previously installed diesel-powered pump). Pumps in Cell E transfer water that meets the current Water Licence (W2012L2-0001) effluent quality criteria into Leslie Lake (at SNP Station 1616-30). Pumping rates into Leslie Lake are up to 2.55 m3/s from 1 May to 31 July, and 0.52 m3 per second at other times (approximately 6 to 8 million m3 annually).

Access roads Roads are located along the north side of Cell A; around the perimeter of Cell B; along the east, west, and south sides of Cell C; and along the east side of Cells D and E. The Fox Pit road extends from the processing plant to the outlet dam across the Outlet Dam.

Pipelines, spigots, and power lines

Pipelines and spigots are used for the delivery of the PK slurry from the processing plant along the access roads. These run along the east, west, and north side of Cell C and the north side of Cell A. The construction of the Cell C West Road allowed access to construct a pipeline to further maximize tailings storage space. Power lines have been installed to the Outlet Dam to operate electric pumps that are used to pump the water from Cell E to Leslie Lake to reduce environmental risks associated with diesel pumps. Recently (in 2017) a weir was installed at Cell D to further reduce the need for diesel pumps.

PK = processed kimberlite; LLCF = Long Lake Containment Facility; LOM = Life of Mine; SNP = Surveillance Network Program.

Operational water quality monitoring is conducted within Cell E of the LLCF at SNP Station 1616-30. Water quality is also monitored at Leslie Lake and other lakes downstream of the LLCF (see ERM 2017b). Indicators measured are water quality, sediment quality, physical limnology, phytoplankton, zooplankton, and lake benthos. Details on the monitoring methods and results are found in AEMP annual reports (such as ERM 2017b).

PAT

H: T

:\01-

proj

ects

\Eka

ti\P

roje

ct_M

XD

\EK

A-1

5-17

1h.m

xd P

RIN

TED

ON

: 201

8-06

-14

AT:

2:1

5:18

PM

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0


PROJECT

EKATI DIAMOND INTERIM CLOSURE AND RECLAMATION PLANVER. 3.0

TITLE

LLCF AREA CURRENT EXTENT AND CLOSURE PLAN

#### #### 0 5.6-1PROJECT NO. CONTROL REV. MAP

1:40,000 METRES

NOTE(S)

REFERENCE(S)

KEY MAP

PHASE 1PKCA

CELL D

CELL C

CELL B

CELL A

WASTE ROCKSTORAGE AREA

UPPER EXETER LAKE LITTLE REYNOLDSPOND

FAYBAY

MOOSELAKE

LESLIELAKE

DIKE B SPILLWAY

DIKE D SPILLWAY

OUTLET DAM BREACH

DIKE C SPILLWAY

OUTLET DAM

DIKE D

CELL E

DIKE C

DIKE B

MAINCAMP

AIRSTRIP

KODIAK LAKE

LITTLELAKE

LARRYLAKE

PELZER POND

510500 511000 511500 512000 512500 513000 513500 514000 514500 515000 515500 516000 516500 517000 517500 518000

7173

000

7173

500

7174

000

7174

500

7175

000

7175

500

7176

000

7176

500

7177

000

7177

500

7178

000

7178

500

7179

000

7179

500

7180

000

7180

500

LEGEND

#* EXISTING SPIGOT (2017)

FLOW DIRECTION

RESIDUAL DRAINAGE/POND

PROCESSED KIMBERLITE DEPOSITION

OTHER RECLAIMED AREAS

VEGETATED AREA

#*

#*#*

#*#*

#*

#*

#*#* #*

#*

#*

#*

#*#*

#*

#*#*

#*

PHASE 1PKCA

CELL D

CELL C

CELL B

CELL A

WASTE ROCKSTORAGE AREA

UPPER EXETER LAKE LITTLE REYNOLDSPOND

FAYBAY

MOOSELAKE

LESLIELAKE

OUTLET DAM

DIKE D

CELL E

DIKE C

DIKE B

MAINCAMP

AIRSTRIP

KODIAK LAKE

LITTLELAKE

LARRYLAKE

PELZER POND

510500 511000 511500 512000 512500 513000 513500 514000 514500 515000 515500 516000 516500 517000 517500 518000

7173

000

7173

500

7174

000

7174

500

7175

000

7175

500

7176

000

7176

500

7177

000

7177

500

7178

000

7178

500

7179

000

7179

500

7180

000

7180

500

CLIENT

2018-06-14

MJ

MS

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED

0 1,000 2,000

*Existing Status: Satellite Imagery July 2017 (Dominion)

EXISTING CONDITIONS FINAL CONDITIONS

JR

LN



Monthly water levels for Cell E, summary of process water use in the LLCF, water pumped to the LLCF, Discharge volumes from the LLCF, summary of treated sewage effluents to the LLCF, and Discharge water quality are reported in monthly SNP reports and the Water Licence and Environmental Agreement annual reports (such as Dominion 2018f). Additional detail on the operational aspects of water volumes and management can also be found in the Wastewater and Processed Kimberlite Management Plan (DDEC 2017l).

The basis of the current LLCF PK deposition plan was established through a comprehensive review of the LLCF development plan in 2005 (Robertson GeoConsultants 2005) and an evaluation of deposition completed in 2011 (BHP Billiton 2011b). The selected deposition plan maximized the utilization of storage capacity in Cells A, B, and C in favour of deferring or avoiding PK deposition into Cell D through the formation of PK beaches in Cells A, B, and C. PK deposition into Cells A and C of the LLCF will continue until the remaining current storage capacity for solids is exhausted. During PK deposition into Panda/Koala Pit, the LLCF will be utilized to manage minewater decanted from the pits. Additionally, the LLCF will be utilized to pump flood Fox Pit.

At the end of PK deposition, it is estimated that an area of approximately 728 ha (Cell B = 199 ha, Cells A and C = 529 ha) will need to be reclaimed. Based on reclamation research results, three distinct topographic units that will develop within LLCF in closure have been identified: 1) gently sloping, well-drained PK beaches (for revegetation); 2) residual ponds in Cells A, B, and C; and 3) interface shorelines where beach deposits meet the ponds. Each unit will have predictable geomorphic attributes, geographic distribution, and soil properties that allow for evaluation and optimization of reclamation prescriptions. Map 5.6-1 shows the proposed reclaimed LLCF after the closure activities have been implemented; the reclaimed LLCF also shows a conceptual layout of the final LLCF conditions, which includes vegetation and rock, residual ponds, pond interface, and drainage.

Progressive reclamation by the active and passive establishment of natural vegetation has been occurring since 2004, and LLCF reclamation research at Cell B has been ongoing at the Ekati mine since 2012 to develop prescriptions for vegetation growth on the PK beaches in the LLCF (Photo 5.6-1). Residual ponds and drainage channels have been established in Cell B (Photo 5.6-2). Surface water management research through trial channel construction and further bio-engineering of existing channels so that they are stabilized for closure is also being completed.



Photo 5.6-1 Long Lake Containment Facility (Cell B) Research Area (photo taken August 2017)



Photo 5.6-2 2017 Long Lake Containment Facility Reclamation Area (photo taken August 2017)




Section 5.2 described the site-wide closure considerations, reclamation approach, closure objectives, and site-wide closure criteria. Based on the closure goals and principles for the Ekati mine ICRP, closure objectives were identified specifically for the closure and reclamation of the LLCF (Table 5.6-4). The overall closure approach for the LLCF has been developed through reports and studies, beginning with the original EAs, ICRP Version 2.4 (BHP Billiton 2011a), and through annual closure and reclamation progress reports.

Table 5.6-4 Closure Objectives and Criteria for the Long Lake Containment Facility


LLCF-1 Water quality is acceptable for entry to the Receiving Environment.

Manage water in the LLCF until water quality is suitable for release to the Receiving Environment, after which the outlet dam will be breached.

Water quality complies with water quality closure criteria.

Routine water quality monitoring

LLCF-2 Connectivity is established between Cell E of the LLCF and Leslie Lake to allow for safe fish passage.

Breach outlet dam at Cell E to allow fish passage.

Build is per design. Physical inspection by qualified professional

LLCF-3 PK surfaces are physically stable.

Construct physical stabilization cover with vegetation or competent material where required. Design dike breaches and construct channels, where required.

Vegetation cover is sufficient to stabilize surface. No significant slumping, subsidence, or erosion is occurring as determined by a geotechnical engineer. Dike breach, channel construction (if required), and further bio-engineering of existing channels, is carried out per the design. Stability of residual channels is comparable to natural channels in the area. Dustfall levels at associated monitoring stations do not pose risk to wildlife, aquatic systems, or humans.

Physical inspection by qualified professional Routine dustfall monitoring

LLCF-4 Wildlife can safely move within the reclaimed LLCF areas.

Develop a specific cover design that enables safe wildlife movement within the LLCF.

The cover design does not create barriers to wildlife movement within the LLCF.

Routine site-wide monitoring through the WEMP

LLCF-5 Vegetation on LLCF is safe for consumption by wildlife or humans.

Complete a risk assessment based on metal uptake values of vegetation species on PK at closure.

Risk from metal uptake from vegetation or PK is acceptable, based on site-wide risk assessment values considering wildlife and humans.

Monitoring of metals in vegetation and soil

LLCF = Long Lake Containment Facility; PK = processed kimberlite; WEMP = Wildlife Effects Monitoring Program.




LLCF research continues to actively incorporate community involvement and engagement with community members and TK holders. This involvement will continue to be integral in developing the final stabilization cover for the LLCF. Section 5.6.5.2 describes projects undertaken by Dominion to involve communities in LLCF research, and to solicit feedback on closure approach and desired outcomes. The Kugluktuk Traditional Knowledge Program, community student participation, and the 2013 vegetation workshops were all opportunities for communities to provide feedback on PKCA closure approach and activities. During other recent engagement activities specific to the ICRP (e.g., the 2018 ICRP workshop and community visits), feedback regarding the closure and reclamation of the PKCAs has been limited. The TKEG meetings in 2017 noted general concern about the extent of the reclamation required in PKCAs and the ability of the areas to return to suitable habitat for wildlife. General concern regarding potential changes in the suitability of vegetation and animals for harvesting and consumption as a result of the removal of PK was raised by some in the 2018 community visits, as was the potential for residual kimberlite to contaminate groundwater.

5.6.4. Consideration of Options and Selection of Closure Activities

The main closure objective for the LLCF is to provide physical stable surface on the PK that will be safe for wildlife movement and have vegetation safe for wildlife consumption. The LLCF closure objectives will be achieved through the construction of a stabilization cover with vegetation or competent material where required. In addition, there will be a need to design dike breaches and construct channels for surface water management through the LLCF. Water quality acceptable for release to the Receiving Environment will also be expected at closure. The consideration of options and selection of closure activities to meet these objectives have been and will continue to be driven by LLCF reclamation research to develop reclamation prescriptions for the LLCF (see Section 5.6.5.2).



The closure approach for the LLCF provides erosion protection of the exposed PK beaches through vegetation with incidental rock covering, where required. Closure activities to be completed as part of the LLCF reclamation are as follows:

• PK surface will be vegetated and rocks will be placed on the PK (opportunities for expanded reclamation research and progressive reclamation will be evaluated during the LOM).

• Water drainage channels within Cells A, B, and C will be constructed to convey surface water flow through the containment cells in a controlled manner that mitigates erosion risk.

• Spillways will be constructed in Dikes B, C, and D of the LLCF to allow natural flows through the containment cells.

• Outlet Dam theirmistors will be removed and the dam breached in a manner that allows fish passage.

• Pumps and pipelines will be removed at the Outlet Dam.





Kugluktuk Traditional Knowledge Project

Kugluktuk Elders visited the Ekati mine in 2017 (Photo 5.6-3). The focus of the site tour was the Cell B LLCF Reclamation Research Area with the goal of familiarizing the Elders with the LLCF reclamation research program. Elders from Kugluktuk were able to share some of their TK from residing near saline coasts. The site visit is summarized in Appendix C. Building on this initial engagement effort, Dominion has filed a research application with Government of Nunavut to complete research work in the community of Kugluktuk in 2018. The research program’s overall aim is to incorporate TK through partnership with local community experts. It is proposed for the Ekati mine staff and its vegetation consultant experts to visit Kugluktuk and with the help of community members to collect a small amount of seed (less than 1 kg) and (possibly) a few live specimens of plants found growing in salt-affected areas along and near the coastline near Kugluktuk. Community guides will share TK of local vegetation and work with the Ekati mine team in selecting the areas of highest potential. Collected material will be transported directly back to the Ekati mine site where seed will be processed and stored and live specimens planted and monitored as part of the ongoing plant species trials being conducted in the PK at the Ekati mine site. It is expected that seed will be planted in spring/early summer 2019 although, time permitting, some seed may be planted in fall 2018. Survival and growth of the resulting plants will be monitored annually for at least three years.

Photo 5.6-3 Kugluktuk Engagement Site Tour at Cell B of the Long Lake Containment Facility (photos taken August 2017)

Community Student Participation

Another key opportunity for community involvement in the LLCF reclamation research program is through the participation of community youth. Annually, youth from surrounding communities are hired on to be involved in LLCF Research Program (Photo 5.6-4). Students receive necessary training and supervision to be allowed safely on the mine site and then aid in a variety of reclamation tasks. Within the LLCF reclamation research program, students have gained exposure and contributed to the following reclamation LLCF research activities:

• implementing mounding as a method of erosion control, where areas were selected based on erosion potential and with high water flow during freshet and following rainfall

• harvesting various seeds including Goose Grass from areas around Cell B for future distribution within the LLCF

• harvesting naturally occurring fungi, including mushrooms, from tundra sites to be propagated and used to establish future vegetative trials within Cell B



Photo 5.6-4 Long Lake Containment Facility Research Community Student Participation (photos taken August 2017)

Vegetation, Rock Placement, Surface Water Drainage Research

At closure, vegetation will be the primary means of PK stabilization. Reclamation research has been ongoing at the LLCF with the overall intent of addressing any uncertainties with the proposed final LLCF cover design. Initial vegetation research field trials completed in Cell B of the LLCF (2000 to 2007) specifically addressed the feasibility of using vegetation to stabilize PK. Building from the successful demonstration that vegetation use for stabilization is achievable, the LLCF research has since focused on types of vegetation that will be most suitable for closure, improvements in soil chemistry, and rock placement designs. Active deposition into Cell B of the LLCF was completed in 2012, and this cell has been used as an LLCF research test area. Investigation and evaluation of reclamation equipment is also included in the reclamation research program to further expand the understanding of leading practice in reclamation. Since 2012, the following reclamation research areas have been investigated:

• plant species trials

• natural colonization

• seed collection

• soil amendment trials

• till top dressing trials

• mine-generated organic matter

• annual crop trials (2016)

• mycorrhiza trials

• vegetation rock plots

The following discussion provides a summary of the results as they pertain to the final closure design. Further details are available in the LLCF reclamation research reports (DDEC 2015a, 2016c, 2017l) included as appendices in associated annual ICRP progress reports (e.g., Appendix F in Dominion 2018e).



Observations of the Cell B surface since 2012 (i.e., post-deposition) indicate success in revegetation with native plant species, and natural colonization (see for example DDEC 2017m). Plant species trials in Cell B are an ongoing component of reclamation research and have indicated that some species are better adapted to the conditions than others. However, given that at least two growing seasons are required for establishment of some species planted as seed, additional time is required before defining the most suitable plant species options.

Field observations of natural colonization of a native northern alkali grass (Puccinellia borealis; also known as “goose grass”) have been ongoing in Cell B since 2004. Satellite imagery comparisons of biomass growth indicate an increasing trend since 2014 with the greatest natural colonization occurring along the east side of Cell B (DDEC 2016c). Ripe seed is also hand harvested from select species at various times and locations around the Ekati mine site annually. Seeds are used for widespread application in the PK (e.g., goose grass), seeded directly into seeding trials in the PK (e.g., bluejoint and purple reed grasses, fireweed, nodding cotton grass), or grown out in a greenhouse for planting as seedling plugs.

Another reclamation research activity being explored for improving soil quality for optimal vegetation growth is the use of organic matter generated from the Ekati mine composter facility. A trial (summer 2016) was set up in a mid to upper slope position on the PK in Cell B to test various rates of mine-generated organic matter application and to assess the value of tilling the material into the PK versus simply spreading it across the surface. Monitoring was initiated in 2017 and results will be evaluated for the feasibility of use in the final closure design.

Cover crops are commonly used in land reclamation to help control surface erosion and introduce organic matter into the soil environment. In the summer of 2015, cover crop trials were initiated with fall rye (with a relatively high fertilizer application), and the results indicated that the nitrogen introduced as a result of the crop increased its overwintering success and produced good growth in its second season. The overwinter success and adequate nutrition supply for a second season of growth suggest a promising future research path for temporary annual cover crops prior to establishment of native plant species.

Soil amendment trials have been ongoing since 2013 to test the potential benefit and practicality of amending the PK surface to ameliorate the negative effects of elevated sodium concentrations in the PK on plant growth and soil structure. Trials are ongoing, with current results showing that incorporation of gypsum and alfalfa pellets into the PK has the greatest positive effect on plant growth. The results also suggest that with the exception of calcium nitrate alone, all of the amendments promote plant growth when compared to PK with no amendments. Alfalfa pellets incorporated into research plots have consistently been among the top performing based on vegetation data; however, additions of organic matter also appear to have a notable positive affect on plant growth in the PK. Generally, there has been a reduction in surface salts in all of the treatments since the study began with the most notable reductions observed in the amended PK.

Glacial till as topdressing over the PK has been explored as another cover option since 2013 with some success (DDEC 2017m). In 2016, results suggested that seeded grasses have become established in the glacial till test plots; however, surface roughening may be required to provide protection from wind. Browsing by rodents has caused seedling mortality and future trials may consider fencing or group plantings within small fenced areas.

Rock placements that support vegetation have been tested through the LLCF reclamation research since 2013 (DDEC 2017m). Various rock and vegetation combinations as permanent cover for the LLCF were established in late summer 2013 and spring 2014 near the north end of Cell B of the LLCF. Trials included rock windrows, boulder field and grids in combination with grass and an annual cover crop (Photo 5.6-5). All rock type configurations showed promising results for promoting the establishment of diverse vegetation types (with the exception of the annual crop). Well-drained upland positions within plots showed a higher survival of woody stems. Browsing by Arctic hare and sik-siks (Arctic ground squirrel, Urocitellus parryii) was the major cause of mortality among the planted seedlings; thus, small fenced areas will likely be implemented for future research.



Photo 5.6-5 Vegetation/Rock Plots Aerial Photo (photos taken August 2017)

Reclamation research at the LLCF has also focused on the identification of the best means of erosion control and flow management (Photo 5.6-6). This research will be used to construct new drainage channels or bio-engineer existing channels within Cells A, B, and C to promote drainage of the residual ponds and to convey surface water flow through the containment cells in a controlled manner that mitigates erosion risk.

Photo 5.6-6 Rock and Vegetation Reinforcements around Natural Drainage in Cell B to Handle Freshet Higher Flow Volumes



Long Lake Containment Facility Research Wildlife Use Observations

Wildlife monitoring of the LLCF is conducted through the WEMP. The WEMP has been developed and adapted over the period of mine operation based on observation and analysis, as well as input through community engagement and TK. Of the 845 surveys conducted at the LLCF between 1999 and 2017, caribou were observed within the vicinity of the LLCF during 120 (14%) of the surveys. Other mammals and birds were also recorded during LLCF surveys, including grizzly bear, wolf, Arctic hare, red fox, Arctic ground squirrel, Canada goose (Branta canadensis), northern pintail (Anas acuta), greater white-fronted goose (Anser albifrons), rough-legged hawk (Buteo lagopus), long-tailed duck (Clangula hyemalis), common loon (Gavia immer), and American green-winged teal (Anas carolinensis) (ERM 2018b).

Incidental wildlife field observations, as well as data from four wildlife cameras installed in the Cell B research areas, show that geese use and graze the Cell B LLCF research area generally in May (after spring freshet) and August (late fall). Arctic hare have also been observed to graze crops in the LLCF. Observations of large mammals including grizzly bears and caribou have also been noted within the LLCF research areas (Photo 5.6-7a-d; DDEC 2015a, 2017m).

a) Arctic hare b) Grizzly bear

c) Geese d) Caribou

Photo 5.6-7 Wildlife Use of the Long Lake Containment Facility Reclamation Area



Vegetation Metals Uptake Analysis

To evaluate concerns that metals in LLCF vegetation (as result of uptake from the PK) could pose a potential risk to wildlife grazing on vegetation, a wildlife and human health Tier 1 risk assessment was completed in 2006 (Rescan 2006b). The main objective of the 2006 risk assessment was to identify and assess the metals that could pose a potential risk to wildlife grazing on vegetation at the LLCF and to humans that consumed the wildlife that grazed on the LLCF. In 2015, re-assessment of the source terms for the current vegetation exposure pathway (assessment of the soil-to-plant uptake of metals in grass species potentially consumed by wildlife) was completed in addition to research on metals bioaccumulation related to caribou interaction with vegetation growing to date in the PK deposited in the LLCF (DDEC 2016c). The bioaccumulation factors calculated in 2015 suggested that there should not be concern for contaminant uptake. This conclusion was based on a comparison of the calculated factors to a range of literature values of soil-to-plant bioaccumulation factors across a variety of agriculturally relevant species that could be consumed by humans or wildlife (including vegetables and feed crops; DDEC 2016c).The factors calculated for the LLCF vegetation were generally in the range of the values in the academic literature.

2013 Vegetation Workshops

Local Indigenous groups have traditionally depended on various natural resources for their survival needs. Through their traditional use of the land while living and travelling on the lands that are within the Ekati claim block, they have accumulated very important knowledge on the types of flora and fauna in the area and the types of habitat in which these are found. This knowledge will be of particular benefit to using vegetation for stabilization of the PK at the LLCF and also for other areas at the mine (see Section 5.8).

In 2013 members from the communities of Kugluktuk, LKDFN, YKDFN, NSMA, and Tłı̨chǫ Government participated in a vegetation workshop. A key purpose of the workshop was for the Ekati mine staff to learn from participants knowledge about the types of flora and fauna in the area and the types of habitat in which these are found. The vegetation workshop had two steps: 1) an initial preparation workshop with community advisors, and 2) an overall vegetation workshop that involved a larger diverse group of participants. The workshops were an important opportunity to share TK and scientific information on local and site-based vegetation research projects. The workshops are outlined in detail in the 2013 annual progress report (DDEC 2013c) and are summarized below.

The initial preparation workshop with Community Vegetation Advisors took place was attended by community vegetation advisors from the IBA communities, who were identified through their local community organizations as knowledgeable of tundra vegetation. The preparation workshop included outlining the role of the community vegetation advisors by discussing the information and experience that the community vegetation advisor will bring to the workshop and planning of tasks for the individual vegetation workshops.

Following the initial preparation workshop, three overall vegetation workshops were completed, which included a community vegetation advisor from the local communities, TK Holders and youth from each of the IBA communities, a vegetation consultant and reclamation planner from the Ekati mine team, and the Ekati TK advisor.

• Tłı̨chǫ Government—19 to 21 August 2013. Participants: Two elders, one youth, and one translator

• YKDFN and LKDFN—23 to 26 August 2013. Participants from YKDFN: Two elders, one youth, one community vegetation advisor, and one translator. Participants from LKDFN: Two elders, one community vegetation advisor, and one youth.

• KIA and NSMA—26 to 28 August 2013. Participants from KIA: Two elders, one community vegetation advisor, one youth, and one translator. Participants from NSMA: One elder, one youth, and one community vegetation advisor.



Although there were some variations between the three workshops (dependent on weather, physical ability of group participants, and length of each workshop) the general format of the overall vegetation workshop was the following:

• Overview of the vegetation workshop agenda, the ICRP, TK programs at the Ekati mine, and plants.

• Visit to the Fox Pit view stand to discuss the conceptual plan for flooding pits and construction of littoral zones.

• Visit to the LLCF and discussion on the natural colonization of alkali grass on PK, and the Cell B reclamation pilot study.

• Visits to a local tundra area to allow participants to walk on the land and talk amongst the group about the different tundra plants, TK of plants, and the spiritual importance of the land. A group discussion was held on the plants that were observed during the tundra walks, and their uses. Samples of plants were collected during the tundra walks by the participants, to assist with the discussion.

Included as part of the vegetation workshop was presentations by Community Vegetation Advisors that shared the following information:

• the medicinal uses of spruce gum, and how it is collected by Terri Enzo (LDKFN)

• Colomac Mine reclamation efforts by Johanne Black (YKDFN)

• how to collect plants, and how to build a fire on the tundra demonstration by Kate Inuktalik (KIA)

In general, the workshops successfully enabled the sharing of TK information which was utilized in the future LLCF reclamation research planning and design efforts. Specifically, the types of species that could be successful in reclamation was incorporated into the species trials evaluations. A summary of the information shared during the vegetation workshop by community participants is provided in Appendix C.

Long Lake Containment Facility Permafrost and Other Research Studies

Permafrost development is an important consideration in the final LLCF closure design and water quality in closure. The majority of PK surface area will be well-drained sloping beach sediments. The high proportion of well-drained beaches will encourage formation of permafrost from the surface downward. The ponds may remain with an unfrozen zone or “talik” below those areas where water depth exceeds the natural winter ice thickness. Interface zones where the pond will freeze to the bottom sediments each winter will sustain permafrost but would be expected to have a thickened active layer. Where PK is placed over what was originally exposed tundra (outside the original lake shore), permafrost aggradation will occur from above and below the PK. Where PK is placed over a former talik area, permafrost aggradation will occur from the top downward. A winter investigation program was completed in 2013 to characterize FPK and porewater concentrations in Cell B of the LLCF. A field drill program was also completed to assess the permafrost development in the LLCF and to install thermistors for ongoing monitoring. Investigation results indicated permafrost aggradation into Cell B and evidence of weathering and porewater expulsion in the porewater concentrations (DDEC 2014b).

Other research studies at the LLCF over time have included:

• PK weathering—A comprehensive geochemical testing program was completed to evaluate the potential effects of sodium concentrations and its overall effect on revegetation in Cell B of the LLCF. The main conclusion was that sodium-bearing clay in Fox ore is likely the major source of sodium observed in the LLCF PK, and the primary mechanism for sodium release is through cation exchange (detailed results are provided in Appendix G, DDEC 2016d).



• Stabilization of extra-fine PK—A field program was completed in 2016 to confirm that there are no longer suspended solids near the surface of the pond (i.e., extra-fine PK has settled). The study confirmed recent visual observations and proposed that trends of settlement of extra-fine PK (i.e., re-suspension) will be documented during monthly inspections of the LLCF (Appendix H, DDEC 2016d).

Long Lake Containment Facility Water Quality Predictions

Preliminary closure water quality modelling of the LLCF was conducted in 2013 using the Koala watershed water quality model as part of the evaluation for back-flooding Fox Pit with LLCF water (ERM 2013). In the absence of water quality closure criteria, water quality benchmarks as defined in the Aquatic Response Framework (and historically as part of the AEMP; ERM 2017d) have been used to screen the closure water quality predictions discussed below. The flooding of Fox Pit Lake will require the pumping of water from the LLCF for 19 years (see Section 5.3.5.2.3). Water quality predictions indicate that this will not result in significant positive or adverse effects on LLCF water quality in Cells D and E (ERM 2014).

The model results predict that with cessation of pumping PK and minewater at the end of operation, natural runoff will dominate the water balance of the LLCF, resulting in the dilution of water quality variables within the facility. After reaching a steady state, exceedances of benchmarks may occur for water quality variables with benchmarks that are hardness dependent (e.g., cadmium, copper, lead, nitrate, nickel, and sulphate) because water hardness is predicted to decrease within the LLCF and downstream lakes after the end of operations and the coinciding hardness dependent benchmark is expected to fall more rapidly than the concentration of the variable.

Since the modelling in 2013, the Koala watershed water quality model has continued to be updated using the best current estimates of source terms and LOM Plan, with the most recent update being in 2017 (ERM 2017e). The 2017 model predictions continue to show a general decline in concentrations towards the end of the mine life (ERM 2017d). Thus, similar to what was completed in 2013, extending the 2017 LLCF model through closure is anticipated to show further decline and limited exceedances of benchmarks.

The Koala watershed water quality model, and specifically the LLCF load balance model (a sub-model), will continue to be updated in step with LOM planning. Where possible, the model will incorporate information from the reclamation research program as it becomes available to help evaluate loading sources such as surface water runoff over exposed beaches, considering the effect of vegetation of the beaches, and other updates regarding the LLCF water management through LOM.


Stability of Long Lake Containment Facility Surface

Physical stabilization of the PK surface, which is estimated to represent approximately 728 ha by the end of mine life, is a fundamental closure objective for the LLCF. The physical stability of the PK in the LLCF will be achieved through the use of long-term cover, coupled with surface water management via dike breaches and construction of channels, where required, based on the final PK topography.

The long-term cover will be a combination of vegetation and rock placement, the specific details of which will be determined through the annual LLCF research program and incorporated into the final design. Vegetation is planned to be the main stabilization component of the PK. Rock placement is intended to promote a localized environment for vegetation growth and also provide larger-scale wind and water erosion protection. As identified in Section 5.6.5.2, a number of viable options have been identified; however, through research, the preferred vegetation, soil amendment (if required), and rock placement designs will be developed for all cells with PK deposition. The expected timeframe to achieve sustainable vegetative growth will be identified through the ongoing revegetation research in Cell B.



Surface water management will be initiated with the construction of spillways (water level control weirs) in Dikes B, C, and D of the LLCF. Seepage through the dikes is expected to diminish with time as the filters bind off, and most water will therefore pass over rather than through the dikes. The spillways will be permanent features in the new landscape that control water elevation and allow surface water to decant from one cell to the next within the basin. Small residual ponds may develop on the upstream side of the spillways and/or in low-lying areas. Water drainage channels within Cells A, B, and C will be constructed or existing channels will be bio-engineered to promote drainage of the residual ponds and convey surface water flow through the containment cells in a controlled manner that mitigates erosion risk. Reclamation research at the LLCF will continue to identify the best means of erosion control and flow management.

Small residual ponds will likely occur in the low-lying areas of the PK beaches or be encouraged in at the upstream side of spillways in Cells A, B, and/or C (Map 5.6-1). The residual ponds will initially act as a means of settlement of sediment that may be generated from the PK beaches during reclamation and a subsequent period while vegetation is becoming fully established. Surface water management would direct all water to eventually flow to a residual pond in Cell C. Water will decant from Cell C to Cell D, where complete settlement of solids would occur. Water will decant from Cell D to Cell E and from Cell E to the receiving environment (Leslie Lake). The water elevations in Cells B, C, and D after closure will be controlled by overflow structures incorporated into Dikes B, C, and D.

LLCF reclamation research will provide the reclamation prescriptions for the final LLCF closure design activities. The reclamation research studies are planned to continue and may lead to progressive reclamation of the PK beaches in Cells A and/or C during the LOM. Water management with the use of residual ponds and water management channels within Cells A, B, and C, and water quality in Cells D and E will also be considered in the final closure design for the LLCF. Incorporation of TK and community engagement will continue to be an important component of the LLCF reclamation research program.

Wildlife Safety

Wildlife safety when moving within the reclaimed LLCF areas is a closure objective, with the intention that in post-closure, caribou will be able to access and travel through the LLCF as part of their seasonal migrations through the reclaimed mine area. The revegetated LLCF will be dry, flat, and stable with selective rock placement, which should pose low risk to wildlife movement; however, the information collected as part of the LLCF research (including TK) and the Ekati mine WEMP will continue to be reviewed and analyzed within the context of this closure objective to provide design decisions related to final LLCF cover design that support the above findings.

Safe Processed Kimberlite Containment Area Vegetation

The information collected as part of LLCF reclamation research will continue to be reviewed and analyzed within the context of this closure objective to ensure that design decisions related to final LLCF cover design continue to support LLCF research findings regarding vegetation metals uptake (Section 5.6.5.2).

Long Lake Containment Facility and Leslie Lake Connectivity

Surface water management will be initiated with the construction of spillways (water level control weirs) in dikes B, C, and D of the LLCF. When water quality in the LLCF meets closure water quality criteria, the Outlet Dam will be breached. The Outlet Dam breach will restore natural flow from the LLCF to Leslie Lake and the closure objective will be to maintain the connectivity to allow for fish passage—meaning that fish can pass from the LLCF into Leslie Lake (and vice-versa).

The final water level at the Outlet Dam will be lowered to approximately the natural outflow elevation. The catchment area reporting to the LLCF will be similar to the pre-construction catchment (44 ha at pre-construction versus 42.3 ha currently); however, the lake surface area will be reduced from the original (pre-mining) area by approximately 30%. Expected final water balance and volumes of annual water flow from the LLCF after completion of reclamation activities have been calculated and suggest that average annual natural outflow (7.6 million m3/yr; ERM 2013) is similar to pre-development Long Lake (8.0 million m3/yr; Table 5.6-2).



The connectivity of the LLCF and Leslie Lake to allow for fish passage (as a closure objective) will be achieved through the final design for the Dike B, C, and D weirs, and for the breach of the Outlet Dam. Dominion will prepare a design report for the WLWB’s approval that will describe the works to be constructed that will allow the LLCF to freely drain to Leslie Lake without need for inspection and maintenance over the long term, while also allowing connectivity for fish passage. Subsequently, an as-built report will be filed to show that these structures have been constructed according to the approved final design using good engineering practice.


Engineering designs for the PKCA closure will continue to be refined and presented to stakeholders and the WLWB in future versions of the ICRP, with final versions being outlined as part of Final Closure and Reclamation Plan. Final versions of designs and plans may also be developed earlier if the closure work is selected to be conducted as progressive reclamation. Provided in Table 5.6-5 are the identified uncertainties that will be the focus of reclamation research moving forward. The referenced research plans are provided in Appendix E.

Table 5.6-5 Processed Kimberlite Containment Area Closure Uncertainties


Whether vegetation in the LLCF cover can provide sufficient long-term stabilization RP 8 – Long Lake Containment Facility Stabilization Cover

What will be the implications for water quality in the LLCF after closure RP 9 – Long Lake Containment Facility Water Quality

LLCF = Long Lake Containment Facility; RP = research plan.


Collection of monitoring data as part of LLCF reclamation research will continue at the Ekati mine. Provided below are general details of the monitoring program and maintenance requirements envisioned after reclamation of the LLCF has been completed:

• Water quality monitoring will be conducted to demonstrate that the closure water quality criteria have been met and the water quality closure objective has been achieved. The overall duration, scope, and frequency of monitoring will be dependent on the observed monitoring trends and results.

• Regular inspections of the facility will be completed to identify signs of significant erosion, subsidence, slope failures, surface instability, that proper water drainage conditions have been established, and that water is being channelled as designed. When requried, maintenace activties will completed to fix any issues identified in the insepctions.

• Dustfall will be monitored to demonstrate that PK stabilization has been effective and to verify that levels do not pose risk to wildlife, aquatic systems, or humans.

• Annual vegetation surveys will be completed to track natural colonization, cover percentage, and temporal growth.

• Metals content of the vegetation cover will be analyzed to verify that it remains safe to eat for wildlife.

• Flow between Cell E and Leslie Lake will be monitored to document that it is sufficient to establish connecitivity for fish.

• Wildlife use of the LLCF will be tracked through site-wide monitoring efforts. If monitoring results indicate higher use than expected, targeted monitoring (e.g., camera locations) may be warranted.



5.6.7.1. Reporting

A report summarizing site activities, compliance and environmental data will be prepared as required by the Water Licence (currently annual and may change as closure progresses) and the Environmental Agreement (annual). Additionally, the three-year EIR report will be prepared as required by the Environmental Agreement. These mechanisms will provide a consistent reporting regime for reclamation activities and progress.

A reclamation completion report will be prepared for specific mine components to document when closure objectives have been achieved and relinquishment can proceed (see Section 5.2.8 for more information on relinquishment documentation).


Consistent with previous assessments of residual effects related to the PKCAs post-closure, including the various EAs (BHP and Dia Met 1995, 2000; DDEC 2013d, 2014b) and ICRP Version 2.4 (BHP Billiton 2011a), all residual effects that will remain after reclamation work is completed are evaluated as negligible. Residual effects related to the successful completion of the LLCF reclamation are provided in Table 5.6-6.

Table 5.6-6 Residual Effects Following Reclamation of the Long Lake Containment Facility


• Landscape is altered through the revegetation and reconfiguration of the LLCF.

• The revegetated LLCF will be dry, flat, and stable, posing low risk to wildlife movement through the area. Monitoring to date has shown wildlife use within the research plots; however, overall, the area is anticipated to have lower forage potential than the surrounding heath tundra.

• Metals in vegetation cover as a result of uptake from the LLCF are expected to have minimal health concerns for consumption by wildlife and humans consuming wildlife using the LLCF.

• The LLCF Discharge water quality is predicted to have negligible effects on the Receiving Environment through closure. Water will be managed prior to breach of Outlet Dam and monitoring results will be used to evaluate the need for the implementation of additional water quality mitigation efforts at the reclaimed areas.

LLCF = Long Lake Containment Facility.


Acknowledging that there always remains some level of risk that certain reclamation activities are not as successful as expected, a summary of key identified risks and associated high-level contingency measures is provided in Table 5.6-7. Given the current stage of mine development, it is not reasonable to provide greater detail at this time. In practice, should the post-closure monitoring programs identify that conditions are trending in the wrong direction, adaptive management measures will be implemented to adjust to the reclamation activity, closure criteria, or monitoring program so that that closure objectives are achieved. In some cases, response thresholds will be developed and included in the closure monitoring to identify trends when closure criteria will be exceeded and the potential for closure objectives not being met. The refinement of the adaptive management framework for post-closure will continue with future updates of the ICRP.



Table 5.6-7 Key Residual Risks and Contingencies for the Long Lake Containment Facility


Vegetation is not successful in stabilizing PK • Other means to stabilize PK (i.e., more rock)

Water quality at Cell E of LLCF does not meet closure criteria to allow release to Receiving Environment • Investigate source • Temporarily store water in the

LLCF • Evaluate options to improve

efficiency of drainage through the LLCF

LLCF = Long Lake Containment Facility; PK = processed kimberlite.

5.7. Water Management Infrastructure


The pre-disturbance conditions that are specifically applicable to water management infrastructure in the Ekati mine LOM Plan are summarized in Table 5.7-1. A comprehensive discussion of baseline site conditions (equivalent to pre-disturbance conditions) across the entire site is provided in Section 3 of this document. A more detailed description of the structures that make up the water management infrastructure is provided in Section 5.7.1.2.

Table 5.7-1 Pre-disturbance Water Management Infrastructure

Development Area and Water Management Infrastructure

Pre-disturbance Site Conditions

Sable Development • Two-Rock Sedimentation Pond • Two-Rock Dam

• rolling ground moraine • thick till (up to 15 m) • thinner till at easternmost tip of the lake • bedrock, exposed as a cliff along a 120 m section of the north shore • patches of exposed bedrock, isolated boulder fields between east end of Two-Rock Lake and

southwest corner of Ulu Lake • patterned ground, well-defined frost boils, widespread on gently sloping surfaces around Two-Rock

Lake • lacustrine and organic deposits containing excess ground ice underlay a poorly defined, elongated

flat depression just south of Horseshoe Lake, to the north of the outlet of Two-Rock Lake • depression vegetated with dwarf birch and willow, a few boulders scattered across the surface of

the depression, and a concentration of boulders at the outlet of Two-Rock Lake Pigeon Development

• Pigeon Stream Diversion Channel

• Pigeon Stream Diversion Dam

• large flat, low-lying wetland area underlain by organic peat and silt deposits, with underlying bedrock topography

• small ice-wedge polygons are evident along the east side of the Pigeon Stream • a few boulders at surface in the low-lying area, in close proximity to the stream

Panda/Koala/ Beartooth Development

• Bearclaw Dam and Jetty

• Bearclaw-Beartooth stream was 160 m long and had two distinct reaches • unlikely to be fish habitat as it was ephemeral, very shallow, with an average gradient of 11% • aquatic survey results in BHP and Dia Met (2000)

Panda/Koala/ Beartooth Development

• Panda Diversion Dam • PDC

• overlain by Panda Lake • topography and deposits were predominantly glaciofluvial and comprised of sand and gravel

eskers • dominant surficial cover was till veneer less than 2 m thick • till was generally a compact, unsorted mineral soil consisting of a silty-sand matrix with pebbles,

cobbles, and boulders



Development Area and Water Management Infrastructure

Pre-disturbance Site Conditions

Misery Development

• King Pond Dam • KPSF • Saddle Dam • Waste rock dam • East and west coffer dams • Desperation Pond Sump

• King Pond was small (29.1 ha) and shallow (maximum depth of 2.5 m) about 1.5 km north of Misery Lake

• oligotrophic Arctic tundra lake with greater than 2 m of ice cover in winter • less than 5% of pond area not frozen to the bottom in winter • supported immature Arctic grayling (Dillon 1999) and could support slimy sculpin and ninespine

stickleback

Jay Development

• Jay Pit dikes (Jay Dike, North Dike)

• Sub-Basin B Diversion Channel

• in the Lac du Sauvage basin, which has drainage area of 1,461 km2 • Lac du Sauvage is located at the headwaters of the Coppermine River • land areas generally flat with local surface relief only up to 20 m • elevation from 416 to 465 masl

PDC = Panda Diversion Channel; KPSF = King Pond Settling Facility; masl = metres above sea level.


The water management infrastructure at the Ekati mine includes a number of dams, dikes, channels, and ponds currently in operation. It will also include additional future facilities that are planned in support of open-pit and underground mining developments. Dams and diversion channels have been constructed throughout the life of the mine to divert the flow of water around operating pits and underground operations areas and to manage minewater and seepage within settling facilities. Permanent diversion channels were also designed and developed to provide compensation for fish habitat lost as a result of mine development.

In general, the closure conditions for the permanent diversion channels are to have them remain in place and to breach the dams and settling facilities to establish natural flow patterns. The existing and final reclaimed conditions of water management infrastructure are outlined in the subsections below for current and future permitted Ekati mine developments.

The use of Lynx Pit and Misery Pit for storage of minewater is discussed in Section 5.3. The Outlet Dam, Dikes B, C, and D, and other infrastructure associated with the LLCF are discussed in Section 5.5. Water pumping systems and pipelines are discussed in Section 5.8, as well as sumps.

Sable Development

Two-Rock Sedimentation Pond and Two-Rock Dam

The Two-Rock Sedimentation Pond uses Two-Rock Lake to manage minewater from Sable Pit and seepage from the Sable WRSA. A filter dike was constructed in 2017 to divide the Two-Rock Sedimentation Pond into two cells (upstream and downstream). The dike was constructed with waste rock and a sand, gravel silt filter blanket to filter suspended sediments from the water as it moves from the upstream cell to the downstream cell.

Two-Rock Dam was constructed in 2017 at the outlet of Two-Rock Lake to contain the Two-Rock Sedimentation Pond and consists of frozen sand and gravel core water retention dam, protected by crushed transition rock and covered with granite on a permafrost foundation.

Map 5.7-1 outlines the final reclaimed conditions of the Two-Rock Sedimentation Pond being reconnected to the local drainage system (once closure Water Licence criteria are achieved) by breaching the Two-Rock Dam and the Two-Rock Dike. As outlined in Section 5.3, flow from Sable Pit Lake when flooded will be connected to the Two-Rock Sedimentation Pond through a connecting channel.



Sable Diffuser

The Sable Diffuser will be used to Discharge the filtered minewater from the downstream cell of Two-Rock Sedimentation Pond into Horseshoe Lake. The diffuser pipeline will be approximately 270 m in length and will be installed in the deepest part of the southwest basin of Horseshoe Lake. The diffuser pipe will be laid on crush rock placed on the lake bed and then buried with crush rock and rip rap for protection. When no longer required to manage water from the Two-Rock Sedimentation Pond, the above ground piping connection to the Sable Diffuser will be disconnected and reclaimed. The diffuser piping and all associated components at the bottom of Horseshoe Lake will be left in place to minimize disturbance to fish habitat.

Pigeon Development

Pigeon Stream Diversion

Development of Pigeon Pit removed Pigeon Pond and part of Pigeon Stream. The PSD was developed as compensation for loss of fish habitat from development of Pigeon Pit under Fisheries Act Authorization SCA96021. Construction of the PSD was completed in 2014. The overall purpose of the PSD is to divert the Pigeon Stream around the open pit to maintain drainage and allow seasonal passage of fish. The PSD is an approximately 440 m long shallow channel constructed in ice-rich soils. The general cross-section consists of excavated ice rich soil that has been backfilled with thaw-stable fill to create the visible channel. A liner system is included under the channel to encourage flow along the low-grade profile. The PSD includes a deflection berm near the inlet to direct flow into the diversion and a pool near the outlet to provide aquatic habitat and function as a settling basin. About 362 m of riparian edge habitat and 93 m of instream habitat have been planted in the PSD (ERM 2015b). In closure, it is planned that the PSD and Pigeon Berm will remain in place with flow to Fay Bay and Upper Exeter Lake. Once completed, the Pigeon Pit Lake outflow channel will also be reconnected to the PSD (see Section 5.3).

Panda/Koala/Beartooth Development

Bearclaw Dam and Jetty

The Bearclaw Dam was constructed in 2003 and prevents runoff from Bearclaw Lake into Beartooth Pit. It is located at the outlet of Bearclaw Lake and is designed to retain up to 3 m of water. It is a frozen sand and gravel core water retention dam, protected by crushed transition rock and covered with granite on a permafrost foundation. The Bearclaw Intake Jetty located adjacent to the dam provides access to the pumping system that pumps retained water via pipeline from Bearclaw Lake to Upper Panda Lake. The Bearclaw Dam will be breached once Beartooth Pit Lake has achieved its closure water quality criteria to re-establish flow from the original outlet stream from Bearclaw Lake to Beartooth Pit Lake. The pump house at the Bearclaw Jetty will be removed, but the Bearclaw Jetty will remain in place to provide opportunity for fish use.

Panda Diversion Channel and Panda Dam

The PDC was constructed from 1995 to 1997 to divert flow from Upper Panda Lake, around Panda and Koala pits and underground operations, to Kodiak Lake. Additional channel widening and stabilization were completed in three locations at the PDC from 2011 to 2014 (DDEC 2016d). The PDC was developed as compensation for loss of fish habitat from the initial development of the Ekati mine under Fisheries Act Authorization SCA96021. The PDC was constructed by primarily blasting through granite bedrock and ground moraine for a total length of 3.3 km, with widths ranging from 4 to 16 m. Seasonal fish passage occurs in the PDC, and constructed fish habit features have enabled fish spawning, rearing, and foraging. It is planned that in closure, the PDC will remain as a long-term diversion of watershed flow around Panda and Koala pit lakes and provide fish passage and fish habitat.



The Panda Dam was constructed in 1997 and separates Upper Panda Lake from Panda and Koala pits and underground operations. It is located around the narrows of Panda Lake, with a normal operating head of 1.3 m. The Panda Dam will remain in place after mine closure to maintain flow into the PDC from Upper Panda Lake (Map 5.7-1). A Panda spillway is planned at mine closure to allow peak flows from Upper Panda Lake into Panda Pit Lake as a protection measure for the PDC.

Misery Development

King Pond Settling Facility, King Pond, and Saddle Dam

Since 2001, King Pond has been modified into the KPSF for use as a sedimentation pond and containment facility for minewater and other runoff associated with Misery and Lynx open pits and the Misery WRSA. The KPSF will be used to manage minewater for the future MUG Project.

The King Pond Dam was constructed in 2001 and is located on the northwest side of the KPSF to block uncontrolled flow into Cujo Lake. The King Pond Dam consists of a frozen sand and gravel core water retention dam, protected by crushed transition rock, and covered with granite on a permafrost foundation. The Saddle Dam is located on the southern limit of the King Pond and encloses the KPSF to the south. The Saddle Dam was constructed as semi-pervious zoned rockfill dam with a non-woven geotextile incorporated within a zone of 20 mm minus material. As part of the planned MUG Project, the Saddle Dam will be upgraded to include a seepage barrier over the existing upstream slope using a geosynthetic clay liner.

Map 5.7-1 outlines the final reclaimed conditions to reconnect the KPSF to Cujo Lake. This will be achieved by breaching the King Pond Dam.

Desperation Pond Sump and East and West Coffer Dams

East and West Coffer dams were constructed in 2001 to retain seepage and runoff from the southern portions of the Misery WRSA into Desperation Pond where it could be Discharged into Carrie Pond or managed through the KPSF. In 2014, as part of expansion of the Misery WRSA, the majority of Desperation Pond was encapsulated within the WRSA. The small area that remains is currently being utilized as a sump to collect seepage and runoff from the Misery WRSA for management through the KPSF. When use of the sump is no longer required for water management purposes, it will be reclaimed by being backfilled with waste rock (see Section 5.8 for reclamation of sumps) and the East and West Coffer Dams will be breached.

Waste Rock Dam

The waste rock dam was constructed in 2001 and is south of the Misery development to retain runoff from the upslope area. The waste rock dam consists of a frozen sand and gravel core water retention dam, protected by crushed transition rock, and covered with granite on a permafrost foundation. For closure, the waste rock dam will be breached to allow flow towards Lac de Gras (Map 5.7-1).

Jay Development

Jay Dikes

The Jay and North dikes will be built around the Jay pipe to allow dewatering of a portion of Lac du Sauvage and subsequent mining of Jay Pit. The Jay Dike will be a water-retaining dike around the Jay kimberlite pipe that will isolate the local portion of Lac du Sauvage overlying the Jay pipe and will be located on the south, east, and north sides of Jay Pit. The dike follows a horseshoe-shaped alignment extending from the shoreline into the lake, and back again. The dike will include a broad rockfill shell, a central zone of crushed granular fine and coarse filters, and a composite low-permeability element along the centreline of the dike.



The North Dike is a small water-retaining dike constructed near the north abutment of the Jay Dike, forming a portion of the structures that will isolate the Jay kimberlite pipe from Lac du Sauvage. The North Dike will be constructed of crushed rockfill with a bituminous geomembrane liner.

Jay Diffuser

The Jay Diffuser will be used to Discharge minewater from Misery Pit into Lac du Sauvage in the latter part of Jay Pit operations. Once Misery Pit has reached the proposed designed operational elevation, water will be drawn from the top of the pit and discharged into Lac du Sauvage through an engineered diffuser outfall. The diffuser will be a multi-port submerged diffuser to ensure mixing of the minewater into the lake. The pipeline will run from the southeast corner of the Jay Dike approximately 300 m into Lac du Sauvage where the lake depth is expected to be approximately 8 m. At closure, the diffuser and associated water lines and pumping systems will be dismantled and removed off site for salvage or disposed of at the on-site landfill.

Sub-Basin B Diversion Channel

The Sub-Basin B Diversion Channel will be constructed before dewatering of the Jay diked area and will be located to the southwest of the proposed Jay Pit. The channel will intercept natural flows from the Lake B0 culvert crossing (beneath Jay North Road) and the Lake Ac35 outlet, and direct them away from the dewatered area and into Lac du Sauvage, south of the Jay Dike south abutment. The diversion channel will allow for fish passage during operations for species such as Arctic grayling to move from Lac du Sauvage to the Sub-Basin B (King-Cujo) watershed.

At closure, the diversion channel will be regraded to promote drainage through the natural drainage pattern to Lac du Sauvage once the water quality in the back-flooded area meets closure criteria for breaching of the dike.

BEARCLAW JETTY

PELZER POND

PANDALAKE

BUSTERLAKE

KODIAKLAKE

POLARLAKE

GRIZZLYLAKE

BEARCLAW DAM

PANDA DIVERSION DAM

PANDA DIVERSION CHANNEL

BEARCLAWLAKE

-12320000 -12315000 -12310000 -12305000

9530

000

9535

000

9540

000

PAT

H: I

:\CLI

EN

TS\D

OM

INIO

N\1

7765

30\M

appi

ng\M

XD

\ICR

P\1

7765

30_M

ap5_

7-1_

Dam

sDik

esC

hann

elsP

onds

.mxd

PR

INTE

D O

N: 2

018-

08-1

4 AT

: 7:0

2:47

AM

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT


PROJECT


LOCATION OF DAMS, DIKES, CHANNELS, AND PONDS

MAP EXTENT

MISERY AREA MAP EXTENT

JAY AREA MAP EXTENT

SABLE AREA MAP EXTENT

PIGEON MAP EXTENT

KEY MAP

0 2,000 4,000

1:60,000 METRES

LEGENDFLOW DIRECTION

BREACHED AREA

CHANNEL / POND

DAM

DIKE

REFERENCE(S)

1776530 3000 0 5.7-1

2018-08-14

MJ

AB

BW

LN


YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED

EAST COFFER DAM

WASTE ROCKDAM POND

DESPERATION POND

MIST LAKE

MOSSING LAKECARRIE POND

CUJO LAKE

THINNERLAKE

SADDLE DAM

KING PONDSETTLING FACILITY

KING POND DAM

WEST COFFER DAM

WASTE ROCKDAM

MISERY AREA

LAC DU SAUVAGE

JAY DIKE

JAY DIKE

JAY DIKE

SUB-BASIN B DIVERSION CHANNEL

NORTH DIKE

JAY AREA

TWO ROCKSEDIMENTATION

POND

TWO ROCK DIKE

TWO ROCK DAM

TWO ROCKSEDIMENTATION POND

SABLE AREA

PIGEON DIVERSION CHANNEL

PIGEON AREA



5.7.2. Water Management Infrastructure Closure Objectives and Criteria

While the use and function of each dam, dike, pond, or channel is unique, the ultimate closure state for the water management infrastructure is for the ponds and channels to be reconnected to the local watershed once water quality meets closure water quality criteria. The PDC and PSD remain permanent features of the post-closure landscape. The overall closure approach for the water management infrastructure has been developed through reports and studies, beginning with the original EAs, ICRP Version 2.4 (BHP Billiton 2011a), and through annual closure and reclamation progress reports.

Based on the goals and principles for the Ekati mine ICRP, four closure objectives were identified specifically for the closure and reclamation of water management infrastructure. The objectives and criteria of the ICRP specific to the closure and reclamation of these structures are presented in Table 5.7-2. Table 5.7-2 also presents the general reclamation activities associated with achievement of the closure objectives. These activities are discussed in more detail in the following subsections. An overview of criteria is presented for each objective, with numerical values (where applicable) to be developed for the Final Closure and Reclamation Plan.

Table 5.7-2 Closure Objectives and Criteria for Water Management Infrastructure


WM-1 Water quality is acceptable for entry to the Receiving Environment.

Manage water in respective facilities until the water is suitable for entry to the Receiving Environment, after which connection to the Receiving Environment is established and dikes are breached.

Water quality complies with closure water quality criteria.

Routine monitoring Physical inspection by a qualified professional to confirm breaches constructed in accordance with design intent

WM-2 Reclamation is in accordance with Fisheries Act Authorizations, where applicable.

Reclaim King Pond as outlined in Fisheries Act Authorization File SC00028.

Reclamation is as outlined in Fisheries Act Authorization File SC00028.

As outlined in Fisheries Act Authorization File SC00028

WM-3 Permanent channels, breaches, and Jay diked areas on site are stable to a degree that is consistent with natural stability.

Design and build channels, breaches, and Jay diked areas to avoid erosion in excess of natural systems.

Channels are built in accordance with design, with no significant slumping, subsidence, or erosion occurring during the post-closure monitoring period


WM-4 Remaining water retention structures are stable, where applicable.

Confirm Panda Dam is stable in closure.

Remaining operational structures have a design and as-built report, are signed off by a Professional Engineer, and constructed to standards as applied to the Canadian Dam Association guidelines (CDA 2013), and/or as determined by risk assessment



Community engagement to date has not identified significant concerns or recommendations pertaining to water infrastructure at closure. As part of the Jay Project engagement the prevention erosion and promotion of long-term stability in within the breached Jay dike areas was discussed. Interest has been expressed regarding clarification on the closure plan for the PDC. Dominion will continue to engage with communities on all aspects of closure, including water infrastructure and management.




The major design choices and closure options selection for water management infrastructure have been completed and approved through the regulatory process (i.e., the 2011 ICRP, annual progress reports, Jay Project Closure Plan). No new closure options have been considered for water management infrastructure as part of the development of ICRP Version 3.0.



The selected closure options and associated closure activities for water management infrastructure at the Ekati mine are outlined in Table 5.7-3.

Table 5.7-3 Selected Closure Options and Activities for Water Management Infrastructure

Infrastructure Selected Closure Options and Activities

Two-Rock Dam, Panda Dam, Bearclaw Dam, King Pond Dam

Remove thermal monitoring infrastructure or cut flush with surface.

Bearclaw Jetty Remove Bearclaw Jetty pipeline and pump house and leave jetty in place.

Two-Rock Dam, Two-Rock Dike, Bearclaw Dam, King Pond Dam, waste rock dam, east and west coffer dams

Breach infrastructure to reconnect to local drainage and stabilize slopes with riprap as necessary.

Jay dikes Strategically breach the Jay Dike in several locations. Reclaim riparian (shoreline) and littoral (shallow) areas of the natural shoreline within the diked area. Reclamation work will include localized repair of erosion, and revegetation of selected areas with aquatic and riparian plants.

Sub-Basin B Diversion Channel

Regrade temporary diversion channel to re-establish flows through the natural drainage pathway to Lac du Sauvage. Additional regrading to facilitate wildlife movement in selected areas may also be undertaken.

PSD, PDC Keep permanent diversion channels in place and operational in closure.

Panda Dam Keep Panda Dam in place for closure and construct Panda Spillway to enable peak freshet flows from Upper Panda Lake into Panda Pit Lake.

Two-Rock Sedimentation Pond

Reclaim Two-Rock Sedimentation Pond based on review of sediment and water quality in the upstream cell of the pond at completion of Sable Pit operations. If sediments need to be removed from the Two-Rock Sedimentation Pond, they would likely be deposited at the bottom of Sable Pit.

KPSF Reclaim the KPSF as outlined in Fisheries Act Authorization SC00028. As per the existing Authorization, the current plan includes removing sediments within King Pond that degrade the quality or interfere with the enhancement of fish habitat; re-establishing the King Pond outflow channel; and enhancing drainage and migration corridor between King Pond and Cujo Lake.

PSD = Pigeon Stream Diversion; PDC = Pigeon Diversion Channel; KPSF = King Pond Settling Facility.


Studies, monitoring, and research programs have been, and continue to be, completed to optimize water management infrastructure at the Ekati mine. This includes the progressive reclamation of the PSD (documented in Chapter 6), ongoing engagement, and monitoring of the permanent diversion channels. Learnings from these programs are incorporated into the maintenance and modification of existing structures, and the design and construction of future structures.



Monitoring of Permanent Diversion Channels as per Fisheries Act Requirements

After construction of the PDC in 1997, a 10-year monitoring program (1999 to 2008) was established under Fisheries Act Authorization SCA96021, to assess the effectiveness of the PDC in providing spawning and rearing habitat for Arctic grayling, to assess the productivity of the PDC in comparison to natural streams, and to monitor the revegetation of its banks (Rescan 2010). Results of the monitoring completed up to 2011 indicated that the PDC was successfully providing functional fish habitat and that vegetation was establishing itself along its banks. The PDC was found to provide spawning and rearing habitat for Arctic grayling and other fish species and to serve as a migration corridor between North Panda Lake and Kodiak Lake. It was concluded that the PDC was successful at providing functional and productive fish habitat (Rescan 2010, 2012a).

As requested by DFO, additional habitat enhancements were designed, implemented, and monitored between 2012 and 2014 (Rescan 2012a,b, 2013; ERM Rescan 2013c; ERM 2015a); this included transplantation of instream vegetation and addition of rock habitat structures within the middle reaches of the PDC. Additional channel resloping activities along the steep canyon section of the PDC were also completed to provide further stability to the PDC and increase solar exposure. Dominion is working with DFO to close out the Fisheries Act Authorization.

After construction of the PSD in 2013 and early 2014, a monitoring program was established to assess the effectiveness of the PSD in providing productive fish habitat, under Fisheries Act Authorization SC99037. The 2014 monitoring program showed that the PSD was being successfully used as a migration corridor and rearing, feeding, and spawning habitat for Arctic grayling and up to three other fish species (ERM 2015b). Following the 2015 monitoring program (Year 2), which included a comparison to baseline data collection, the results indicated that the PSD functions as fish habitat as defined in the compensation agreement (ERM 2016c).


Reconnection to Receiving Environment (WM-1)

Most dams and water-retaining structures will be breached, with water flow reconnected to the Receiving Environment. A fundamental closure objective for water management infrastructure is that the water quality inside facilities (i.e., ponds) is acceptable for the Receiving Environment prior to breaching. The monitoring of water quality (and potentially sediment quality where required) during late operations will determine the final plan for the closure of each facilities (i.e., to determine the need for additional pumping of freshwater or removal of sediments). Monitoring will demonstrate that the closure water quality criteria have been met and the water quality objective has been achieved. Once water quality is acceptable, the pond will be reconnected to the local hydrological system through the breaching of dikes or dams. Dikes/dams will be breached according to final designs developed as part of the Final Closure and Reclamation Plan to allow flow out of upstream area such that the pond is no longer retained. Once water quality is acceptable for mixing with the lake, the Jay Dike will be breached in strategic locations to allow circulation within Lac du Sauvage.

Reclamation in Accordance with Fisheries Act Authorizations (WM-2)

Where applicable, reclamation of water management facilities will be conducted in accordance with Fisheries Act Authorizations issued by DFO.

The current Authorization for King Pond (SC00028) outlines the requirements for the reclamation of King Pond to achieve the required compensation (offsetting). The current plans for the closure and reclamation of the King Pond Settling Facility (Table 5.7-4) as described in Fisheries Act Authorization SC00028 include:

• removal of sediments that degrade the quality or interfere with the enhancement of fish habitat



• enhancing bathymetry to improve overwintering habitat

• increasing habitat diversity

• re-establishing the King Pond outflow

• enhancing the drainage and migration corridor between King Pond and Cujo Lake

Authorization SC00028 is valid until December 2020 and Dominion is currently engaging with DFO on how the use of the King Pond Settling Facility throughout Jay Project operations affects the Authorization. It is possible that conditions related to closure and reclamation activities in King Pond may be changed as a result.

The PDC and PSD were designed and built as permanent diversion channels as compensation (offsetting) for Ekati mine developments, as per Fisheries Act Authorizations SCA96021 and SC99037, respectively; these channels will remain in place and provide fish passage/habitat in post-closure.

Dominion is in the process of obtaining an Authorization from DFO for the Jay Project. It is expected that there will be requirements related to closure of the diked area in Lac du Sauvage outlined in the Authorization. Dominion has committed to providing DFO with the closure design for the Sub-Basin B Diversion Channel; the closure design plan will include reclamation of the Sub-Basin B Diversion Channel and reconnection of Sub-Basin B (i.e., King-Cujo watershed) to Lac du Sauvage at closure through the natural drainage path.

Channel Stability (WM-3)

Permanent channels at the Ekati mine will be designed and built to be stable to a degree that is consistent with natural channel stability and sediment/erosion processes. This considers designs that are developed to avoid excessive erosion or slumping/instability of bed and banks. The details of the design will vary between the channels, as a function of anticipated flows, subsurface conditions, channel sinuosity, design cross-section, and other features. Learnings from the observations of channels that are now in their final configuration will be incorporated into the design.

If channels do not meet stability goals in their constructed state, additional works for further stabilization will be undertaken on an as-needed basis. These works could include activities such as seed/vegetation or placement of rock armouring.

Water Retention Structure Stability (WM-4)

The principal water-retaining structure to remain on site after closure will be the Panda Dam. A key closure objective for any remaining water retention structures is that they are stable. Any water retention structures that remain at closure will be designed and built in accordance with applicable dam safety guidelines, such as the Canadian Dam Association guidelines (CDA 2013), and in consideration of the results of a risk assessment.

Design and as-built reports will be signed off by a qualified Professional Engineer. Stability will be confirmed through the applicable monitoring and professional inspections.


No specific reclamation uncertainties have been identified for water management infrastructure that require research plans. Engineering designs for the closure of water management infrastructure will continue to be refined until implementation of closure works. The collection of additional monitoring data during operations will also refine the closure and reclamation planning.




The post-closure monitoring program for the water management infrastructure component will be adapted from the current monitoring programs at the Ekati mine. Monitoring related to the water management infrastructure is summarized in Table 5.7-2.

For Objective WM-1, routine water quality monitoring will be conducted during operations to determine the final plan for the closure of each facility (i.e., to determine the need for additional pumping of freshwater or removal of sediments). At closure, monitoring will demonstrate that the closure water quality criteria have been met and the water quality objective has been achieved. Once water quality is acceptable, the pond or settling facility will be reconnected to the local hydrological system through the breaching of dikes or dams (similarly for the Jay diked area). A physical inspection of the breach will be conducted by a qualified professional to confirm that the breach was in accordance with the design intent.

For King Pond at closure, any monitoring requirements outlined in the Fisheries Act Authorization will be met (Objective WM-2), in addition to those outlined in Objective MW-1.

For Objective WM-2, closure monitoring of permanent channels and breaches will be completed to demonstrate that they are stable. Monitoring will include looking for signs of significant erosion, subsidence, slope failure, and surface instabilities. If required, observed localized instabilities will addressed through preventative maintenance. The PDC and PSD are permanent diversion channels at the Ekati mine that were built as compensation (offsetting) for losses to fish habitat from mine development. As a result, they have requirements to provide suitable fish habitat. Monitoring for these channels during operations has included physical stability, as well as fish habitat presence and use, and fish presence as conditions of the Authorizations; it is expected that during post-closure, monitoring for fish and fish habitat as per the Authorization conditions will be complete.

For Objective WM-4, the Panda Dam is expected to be permanent, and as such, will be monitored through a physical inspection by a qualified professional.

For the purposes of the security estimate, the monitoring costs are estimated to be on a typical duration of 10 years, but the durations for each component will be refined as part of later design. Monitoring would be conducted until closure objectives are achieved.



Residual effects related to the successful completion of the closure works for water management infrastructure are provided in Table 5.7-4. These are consistent with the findings from previous EAs (BHP and Dia Met 1995, 2000; DDEC 2013d, 2014a) and ICRP Version 2.4 (BHP Billiton 2011a).



Table 5.7-4 Predicted Residual Effects for Water Management Infrastructure at the Ekati Mine

Land Use Effects (Wildlife and Human Use)

Environmental Effects (Hydrological Conditions, Water Quality, Aquatic Life, and Fish)

• Remnants of dams and dikes will remain in some areas, which will lead to changes in the appearance of the landscape.

• Remnants of dams and dikes will remain in some areas, which will lead to changes in the habitat types in these areas, and the wildlife travel corridors as compared to pre-disturbance conditions. However, any habitat that is reclaimed at closure will be safe for wildlife.

• Drainage and water quality will be permanently changed by the redesign of the drainage system during operations and the connection of pit lakes and sedimentation/minewater management ponds to the overall closure drainage system. Care will be taken to monitor water quality to determine potential effects of dike breaching or reconnection activities and control the timing of the reconnection to the Receiving Environment.

• The dams, dikes, channels, and ponds associated with the Ekati mine are a permanent change to the aquatic landscape. Some lakes, channels, and ponds that were present at pre-disturbance have been permanently removed (compensation/offsetting developed as requirements under the Fisheries Act to offset losses to fish habitat) and new watercourses and waterbodies have been or will be added. Use by fish within the reclaimed hydrological systems may be different than in pre-mining conditions, but where appropriate, reclamation of ponds and connecting channels will provide conditions that are safe for fish.

5.7.9. Residual Risks and Contingencies

Key residual risks and high-level contingency measures that are associated with water management infrastructure are summarized in Table 5.7-5. Monitoring programs currently in place and described above will detect potential undesirable physical and environmental changes caused by water management infrastructure. Given the current stage of mine development, it is not reasonable to provide greater detail at this time. In practice, should the post-closure monitoring programs identify that conditions are trending in the wrong direction, adaptive management measures will be implemented to adjust to the reclamation activity, closure criteria, or monitoring program so that that closure objectives are achieved. In some cases, response thresholds will be developed and included in the closure monitoring to identify trends when closure criteria will be exceeded and the potential for closure objectives not being met. The refinement of the adaptive management framework for post-closure will continue with future updates of the ICRP.

Table 5.7-5 Key Residual Risks and Contingencies for Water Management Infrastructure


Water quality in ponds or settling facilities does not meet criteria for reconnection to Receiving Environment

• Monitor and test water quality / sediment quality • Delay reconnection to the receiving environment • Additional back-flooding and/or removal of sediments • Further adaptive management measures if required (e.g., design

and implement settling or filtering facilities or passive treatment)

Channel banks or breached areas are not physically stable • Assess cause of instability and evaluate mitigating strategies • Redesign and construct modified channel/breach • Where vegetation used for stabilization fails, update vegetation

plan and revegetate as necessary



5.8. Buildings and Infrastructure


Buildings and infrastructure at the Ekati mine are spread throughout the entire mine area; as such, the Ekati mine site is representative of the pre-disturbance conditions for this component. A comprehensive discussion of baseline site conditions (equivalent to pre-disturbance conditions) across the entire site is provided in Chapter 3 of this document.

A detailed description of the structures that make up the buildings and infrastructure component is provided in Section 5.8.1.2.


A number of buildings and other types of infrastructure are in place at the Ekati mine to support mining operations. The buildings and infrastructure component includes the permanent and temporary buildings and structures, fuel storage facilities, pipelines, pump stations, electrical systems, quarries, pads and airstrip, and mobile equipment.

Pads and Buildings / Storage Facilities

All pads at the Ekati mine are constructed with clean non-PAG construction materials. Camp and satellite facilities pads provide construction base for camp accommodations and for all required buildings and storage facilities. Laydown pads provide for temporary storage of equipment and other items. Kimberlite stockpiles and ore storage pads provide temporary storage of kimberlite before it is processed.

Map 5.8-1 and Table 5.8-1 provide a summary of the current and future planned pad constructions at the Ekati mine. Table 5.8-2 provides a detailed list of the buildings and storage facility infrastructure located on the pads for current and future developments. Photo 5.8-1 through Photo 5.8-3 provide an aerial view of the main camp, Panda/Koala Underground, and Misery Camp pads with their associated infrastructure.

All kimberlite ore located at the stockpile pads will be processed prior to closure. At closure, buildings and associated facilities will be decommissioned. Initially, the pads will be predominantly exposed rock. To promote the natural establishment of vegetation, selective scarifying and vegetation efforts are planned. Surface drainage will be re-established. This could involve the construction of drainage swales within select areas of the camp pads. The Jay pads that are located within the diked area will be submerged at closure.

During the summer of 2014, Dominion held a series of workshops with Indigenous communities to discuss various aspects of the Jay Project. The TK that was shared was that eskers are main travel paths for caribou and the esker is very important. As a result, Dominion committed to stockpile the material from the Jay Road esker cut for use at closure. The esker cut construction was completed in the summer of 2017 (Photo 5.8-4) and the excavated esker material was stockpiled approximately 400 m west of the cut (Photo 5.8-5). The esker cut stockpile location was selected to be on relatively flat ground with low drainage gradients, located near the esker cut. The location and height of the stockpile were designed with consideration of potential wildlife use.

LAC DU SAUVAGE

LAC DE GRAS

DUCHESSLAKE

PAUL LAKE

URSULA LAKE

COUNTS LAKE

EXETER LAKE


Airport

Ammonium NitrateBuilding Pad

JayCrusherPad

Cell B Laydown

Helipad

Geology Pad

Panda/Koala UG Pads

SableExplosive

Storage Pad

Fox SatelliteFacilities

Incinerator Pad

SableSatelliteFacilities

KingPondPad

MainCampPad

MiseryAsphalt Pad

Misery OreStockpile

Pad

Sable Kimberlite OreStorage Pad (Future)

WasteKimberlite

Pad

Esker CutStockpile

MiseryCamp Pad

LynxSatelliteFacilitiesLynx Laydown

Jay ProjectLaydown Areas

PigeonSatelliteFacilities

Fox Fuel Storage Pad

Emulsion Building Pad

Panda/Koala Pit Pads

Primary Stockpile

Secondary Stockpile

500000

500000

510000

510000

520000

520000

530000

530000

540000

540000

550000

550000

7160

000

7160

000

7170

000

7170

000

7180

000

7180

000

7190

000

7190

000

PAT

H: I

:\CLI

EN

TS\D

OM

INIO

N\1

7765

30\M

appi

ng\M

XD

\ICR

P\1

7765

30_M

ap5_

8-1_

Eka

tiMin

ePad

s.m

xd P

RIN

TED

ON

: 201

8-08

-15

AT: 1

:51:

38 P

M

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT


PROJECT


EKATI MINE PADS

MAP EXTENT


KEY MAP

0 5,000 10,000

1:175,000 METRES


WINTER ROAD

WATERCOURSE

WATERBODY



FUTURE FOOTPRINT

HEATH TUNDRA PAD

REFERENCE(S)

1776530 3000 0 5.8-1

2018-08-15

MJ

AB

BW

LN


YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED



Table 5.8-1 Ekati Mine Pads

Facility Description

Sable kimberlite storage pad

• used to store kimberlite from Sable Pit prior to being hauled to the processing plant at the main camp • located adjacent to Sable Road and WRSA • area extent = 11.0 ha

Sable satellite facilities pad • used to hold Sable development infrastructure • contains a trailer-mounted lunch room, field office, and washroom facility that can also be used as an

emergency storm shelter with first aid room and emergency supplies • located southwest of Sable Pit • area extent = 4.7 ha

Sable explosive pad • southwest of Sable Pit • houses primers, detonators, and other blasting supplies • area extent = 0.3 ha

Main camp pad • used to hold main camp accommodations and associated Panda/Koala infrastructure • located west of Panda/Koala open pits • area extent = 46.9 ha

Incinerator/compost pad • located approximately 5 km from the main camp complex • area extent = 0.7 ha

Cell B laydown • located adjacent to the LLCF • area extent = 0.4 ha

Ammonium nitrate (AN) building pad

• capacity for up to 16,500 tonnes of ammonium nitrate • located southwest of the main camp, adjacent to Kodiak Lake • area extent = 3.0 ha

Aviation fuel and geology pad

• used to store aviation fuel tanks and structures to support exploration drilling • located on the Misery Road approximately 1 km from the main camp • area extent = 1.7 ha

Primary and secondary kimberlite stockpile pads

• used to temporarily store kimberlite ore feed to processing plant • located north of processing plant • area extent = 32.3 ha

Panda/Koala Pit pads • located adjacent to Panda/Koala Pits • used for temporary storage of Panda/Koala development infrastructure • area extent = 33.5 ha

Panda/Koala Underground pads

• used to hold above ground Panda/Koala Underground infrastructure • located west of Panda/Koala open pits • area extent = 23.6 ha

Airstrip, helicopter, and airport building pads

• located approximately 1 km from the main camp • area extent = 11.9 ha

Old Camp pad • used to formerly hold Old Camp facilities and infrastructure • area extent = 5.5 ha • hydrocarbon materials were remediated and pad was scarified in 2017

Misery Camp pad • used to contain Misery Camp accommodations and associated Misery infrastructure • located north of Misery Pit • area extent = 12.2 ha

Misery kimberlite storage pad

• used to store kimberlite from Lynx Pit and Misery Pit prior to being hauled to the processing plant at the main camp

• this pad will continue to be used for the MUG Project • located adjacent to the Misery Road • area extent = 13 ha




Esker cut stockpile pad • used to store stockpile material from Jay Road esker cut for future reclamation use • area extent = 1.3 ha

Lynx Pit pad • located adjacent to Lynx Pit to support operations at Lynx Pit • area extent = 2.8 ha

Lynx laydown • a small laydown area at the Lynx Pit constructed using non-PAG construction rock • area extent = 1.5 ha

Fox fuel storage pad • fuel tanks are single lined and housed in bermed areas on an impervious liner • located north of the Fox Pit to support operations at Fox Pit • area extent = 3.0 ha

Fox Pit pad • located north of the Fox Pit to support operations at Fox Pit • area extent = 2.5 ha

Pigeon satellite facilities • located on a pad along the Pigeon Access Road to the southwest of Pigeon Pit to support operations at Pigeon Pit

• fuel tanks are double lined and housed in bermed areas on an impervious liner • area extent = 1.6 ha

Jay crusher pad • used to hold Jay crusher and construction material generated from the crusher • located north of Misery WRSA • area extent = 37.7 ha • will be used as a kimberlite stockpile once crushing activities for Jay Dike construction completed

Jay Project pads and laydowns

• five laydown areas (three to support initial Jay Road construction and two additional laydowns to support dike construction)

• located near Jay Pit area, not yet constructed • planned extent = 55.7 ha • additional kimberlite stockpile area (new ore transfer area) west of the south abutment of the Jay Dike close to

Jay Pit (not yet constructed) • esker cut stockpile located near the crossing of the Jay Road with the esker (constructed)

WRSA = waste rock storage area; LLCF = Long Lake Containment Facility; MUG = Misery Underground; non-PAG = non-potentially acid generating.



Table 5.8-2 Ekati Mine Infrastructure – Buildings and Storage Facilities


Panda/Koala/Beartooth Pit Development

Airport and building • a 1,950 m long airstrip constructed to support various size aircraft (e.g., Hercules C130 and Boeing 727/737 jets); built using esker sand and granite waste rock as the base and compacted crush gravel for the surface

• other gravel-filled areas supporting the airstrip include a parking area, loading and service areas, an access road, and an aircraft control building that are all located at the north end of the airstrip

• also equipped with runway lighting and approach system, navigational aids, radio transmitters, and weather observation equipment

• helipads with capacity for three helicopters • one 50,000 L double-wall Jet A-1 fuel tank housed in a bermed area on an impervious liner associated with

the airport • one 5,000 L double-wall fuel day tank associated with the emergency generator

Main accommodations complex

• dorm-style sleeping rooms for 940 persons; dining, kitchen, and recreation areas; first aid station, emergency response/mine rescue stations; maintenance shops; sewage treatment plant; potable water treatment facility; and incinerator room

• most buildings at the main camp are established using steel piles anchored in bedrock and layers of compacted gravel with insulation; major piping is above ground

• sewage treatment plant, water treatment facility, and incinerator room also adjoin the eastern section of the main accommodations building

• one 35,000 L double wall boiler fuel day tank • one 35,000 L double wall light vehicle fuel day tank housed in bermed area on an impervious liner

Long Lake compost/incinerator complex

• the composter and two incinerators located in the same building approximately 5 km from the main camp complex

• one 15,000 L double-wall fuel tank housed in bermed area on an impervious liner • one 2,200 L double-wall fuel day tank on concrete wall and floors

Central bulk fuel tank farm • eight single wall fuel tanks within a bermed area on an impervious liner • 68 million L of diesel fuel

Power plant • Ekati mine’s main power plant • seven diesel-powered generators, each capable of delivering 4.4 MW at 4,160 V (3-phase) • provides power to the process operations, accommodations, and truck shop / office complex • two 50,000 L double-wall fuel day tanks • one 35,000 L double-wall emergency generator fuel day tank • one 30,000 L single-wall propylene glycol tank on concrete floor and walls • one 15,000 L single-wall engine oil day tank on concrete floor and walls • one 6,000 L singe-wall used oil day tank on concrete floor and walls • three 6,000 L single-wall glycol day tanks on concrete floors and walls

Processing plant • constructed primarily with structural steel sheathed with insulated steel panels and bolted construction on the main frame

• floors are concrete on insulated ground slabs or on metal deck-form work and have interior curbs for the containment of spills

• a security fence surrounds the entire area • one 9,000 L double-wall fuel day tank associated with the incinerator (empty and decommissioned)

Bulk sampling plant • facility was used for initial processing of kimberlite during advanced exploration and construction • can be used for test processing of small batches of kimberlite • facility was moved from Old Camp in 2003 to the main processing plant




Truck shop/offices/ warehouse complex

• complex includes area for heavy and light vehicle maintenance, heated warehouse storage, change rooms, an environmental laboratory, and administration office.

• truck shop and warehouse are on the bottom floor and include seven heavy equipment repair bays, three light vehicle repair bays, two tire-shop bays, one fabrication bay, one lube bay, one bucket welding bay, and one vehicle wash bay

• a warming shed facility adjacent to the truck shop has seven bays used for equipment storage • one 30,000 L single-wall engine oil day tank on concrete floor and walls • one 30,000 L single-wall transmission oil day tank on concrete floor and walls • one 30,000 L single-wall gear oil day tank on concrete floor and walls • two 30,000 L single-wall hydraulic oil day tank on concrete floor and walls • one 9,000 L double-wall fuel tank associated with the warming shed

Bulk lube facility • constructed adjacent to the truck shop in 2002 • two 300,000 L single-wall used oil tanks on concrete floors and walls • two 300,000 L single-wall engine oil tank on concrete floors and walls • one 300,000 L single-wall used glycol tank on concrete floors and walls • one 300,000 L single-wall antifreeze tank on concrete floors and walls • two 300,000 L single-wall hydraulic oil tank on concrete floors and walls • three 100,000 L single-wall transmission oil tank on concrete floors and walls • one 100,000 L single-wall gear oil tank on concreate floors and walls • one 4,500 L double-wall fuel tank in a steel diked area

Ammonium nitrate (AN) storage

• southwest of the main camp, adjacent to Kodiak Lake

Emulsion plant • located 800 m to the north of the ammonium nitrate building • one 22,000 L double-wall fuel day tank

Waste management building • building where waste is prepared for transport to be sent to off-site management facilities; materials are collected and segregated into recyclable and hazardous wastes from operations areas daily

• wastes destined for off-site are stored in sealed barrels on pallets, and B-Train tanks holding bulk liquid wastes, in lined and bermed areas

• two 2,200 L waste management/water separator and bulk tank for used oil storage, double-wall on concrete floor and walls

Site maintenance shed and Sprung facility

• used for shipping and receiving during winter road operations and for aircraft freight; these facilities also house mobile equipment used for general mine site maintenance

Geology and aviation fuel facility

• sprung structure and a number of smaller structures located at the geology pad to support exploration drilling

• eleven 100,000 L and four 50,000 L double wall Jet A-1 fuel tanks used to fuel Ekati aircraft • located on the aviation fuel geology laydown

Continuous air monitoring (CAM) building

• building located within the emulsion plant compound • contains the continuous air samplers, analyzers and dataloggers

Panda/Koala Underground Development

Fresh air raises/fans/portal • Koala and Panda underground mines each have two 4 m wide fresh air raises plus one return air raise that extend from surface to underground

• fresh air raises are fitted with large ventilation fans • access to the three underground mines is via the Koala North Portal located adjacent to the Koala North

open pit • two 50,000 L (one fuel, one used oil) and two 25,000 L (one day fuel, one day used oil) double-wall tanks

associated with the Panda fresh air raise, housed in bermed area on an impervious liner • three 50,000 L and one 25,000 L double-wall fuel tank associated with the Koala fresh air raise, housed in

bermed area on an impervious liner




Maintenance shops (2), warehouse, office complex / change house, compressor building, cold storage building,

• constructed on a pad adjacent to Koala North Pit to support the Panda, Koala, and Koala North underground operations

• one 30,000 L double-wall glycol tank in a bermed area for Koala heat recovery • one 25,000 L double-wall fuel tank housed in a bermed area on an impervious liner to support the Koala

North boiler

Batch plant (for concrete mixing)

• constructed on a pad adjacent to Koala North Pit to support the Panda, Koala, and Koala North underground operations

• includes a 35,000 L double-wall fuel tank in a concrete diked area

Heavy haul fuel bay • a 1 million L fuel tank constructed on a pad adjacent to Koala North Pit to support the Panda, Koala, and Koala North underground operations.

• single-wall fuel tank housed in a bermed area on an impervious liner • one 10,000 L double-wall Koala North fuel-dispensing day tank housed in a bermed area on an impervious

liner

Koala Mine haul day tanks • two 55,000 L double-wall fuel tanks housed in a diked area

Fox Development

Fuel tanks • two 9.5 million L tanks • constructed on a pad north of Fox Pit to support operations at Fox Pit • single-wall fuel tanks housed in bermed areas on an impervious liner

Dispatch trailer, temporary trailer complex (washrooms, lunchroom, first aid station, offices)

• constructed on a pad north of Fox Pit to support operations at Fox Pit • includes a 25,000 L double-wall fuel dispensing day tank housed in a bermed area on an impervious liner

Demag equipment • two decommissioned Demag diesel-hydraulic shovels stored on pad north of Fox Pit

Explosive magazine storage • includes four explosives magazines located adjacent to Cell E of the LLCF • the capacities of the four magazines are 35,000 kg, 35,000 kg, 35,000 kg, and 31,000 kg

Misery Development (open pit and underground)

Camp accommodations • these facilities include accommodations, consisting of single-occupancy rooms, a kitchen complex, recreation room, and exercise gym

• currently provides accommodations for 115 people; a 250-person expansion is planned to support the MUG (80 people) and Jay projects

• two 4,550 L double-wall fuel tanks associated with the accommodations kitchen and boiler

Small power plant, office, first aid facilities, and a small workshop

• located on a pad south of the KPSF and east of the Misery WRSA • facilities will support the operations of both Misery Pit (open pit and underground) and Jay Pit • one 25,000 L double-wall fuel dispensing day tank housed in a bermed area on an impervious liner • one 10,000 L double-wall fuel tank associated with the utilities service building • one 2,000 L double-wall Hotsy fuel tank • one 22,500 L double-wall fuel tank associated with the Misery generators

Emergency response team (ERT) hall

• structure will be installed in an area that is readily accessible from Misery accommodations to minimize response time, potentially next to the utility service building

• will be required for the MUG Project, as the current hall at the Misery site is not large enough for the added underground-rated ambulance and for storing enough closed circuit breath apparatus for multiple response teams

• will be a foldaway style structure to house the surface and underground equipment for quick response from the ERT members




Fresh air raises/fans/portal • MUG mines will require a fresh air raise fitted with large ventilation fans extending from surface to underground

• portals include two in pit locations and possibly a surface portal

Future truck shop • a new truck shop may be constructed at Misery Camp in support of the Jay Project for maintenance of the Jay Project mining fleet and other vehicles

• facility might be two fabric-covered structures, each with two bays • truck shop would be sized to accommodate Jay haulage trucks • one 10,000 L double-wall fuel tank • one 4,500 L double-wall fuel day tank • one 4,500 L double-wall fuel tank associated with the wash bay

Explosive magazine storage • three Type 4 explosive magazines located north of the Jay crusher

9.5 million L bulk fuel storage tank

• single-wall fuel tank within a bermed area on an impervious liner including dispensing and offloading facilities

• storage capacity may be expanded for the Jay Project, if necessary, to optimize the transportation, use, handling, and emissions from diesel fuel for the Ekati mine

• expansion could be as much as double the current capacity

Jay crusher • a rock crusher with a small substation that ties into the power line for power. • set up near the Misery Camp to produce crushed aggregate material for Jay construction activities

Pigeon Development

Fuel storage • located on a pad along the Pigeon Access Road to the southwest of Pigeon Pit to support operations at Pigeon Pit

• fuel tanks are double-lined and housed in bermed areas on an impervious liner

Sable Development

Small warehouse and truck line-up area

• constructed on a pad southwest of Sable Pit • heated warehouse storage and two-bay truck shop

Field office complex • constructed on a pad southwest of Sable Pit • includes offices, lunch room, washrooms, first aid room, and emergency accommodations

Explosives magazine • constructed on a pad southwest of Sable Pit • houses primers, detonators, and other blasting supplies that will be established a safe distance from the pit

Fuel storage • constructed on a pad southwest of Sable Pit • four 500,000 L single-wall fuel tanks housed in a bermed areas on an impervious liner adjacent to the

laydown

Power plant • constructed on a pad southwest of Sable Pit • small stand-alone diesel power plant • small generators will be used to power the field office; this will require a source of 100 amp, 208 V

electrical power, to be provided by a 75 kW generator

Lynx Development

Field office and generators • constructed on a pad adjacent to Lynx Pit to support operations at Lynx Pit

Jay Development

Field office • will be constructed on a pad adjacent to Jay Pit to support operations at Jay Pit • a lunchroom, office, and washroom facility with temporary emergency shelter and supplies will be

constructed at the Jay site

Explosives magazine • up to three Type 4 explosive magazines • proposed to be located near Jay Pit for storage of primers, boosters, packaged products, and surface

delays

LLCF = Long Lake Containment Facility; MUG = Misery Underground; WRSA = waste rock storage area; ERT = emergency response team; KPSF =

King Pond Settling Facility.



Photo 5.8-1 Main Camp Pad Infrastructure

FAR = fresh air raise. Photo 5.8-2 Panda/Koala/Koala Pad Infrastructure



Photo 5.8-3 Misery Camp Pad Infrastructure

Photo 5.8-4 Jay Road Esker Cut

Esker Cut



Photo 5.8-5 Jay Road Esker Cut Stockpile

Quarries

There are three areas, described below, at the Ekati mine where quarrying activities have occurred or are potentially planned to occur.

Airport Esker

The airport esker is a prominent north–south oriented ridge located 1 km southeast of Old Camp that was used as a borrow area for granular material. The airport esker was the main source of granular material during Old Camp operations and in the early years of the Ekati mine site construction with a total disturbance of approximately 35 ha. The site has been partially reclaimed and may be used in future as it contains high quality material and is located relatively close to construction and underground mining activities. Final landscape of the airport esker will consist mostly of exposed rock with vegetation. In closure, any thermokarst erosion or subsidence will be repaired.

Panda/Koala/ Beartooth Waste Rock Storage Area Quarry

The north side of the Panda/Koala/Beartooth WRSA is being used as a borrow area (i.e., as a source of granite material for Ekati mine construction and reclamation). Whatever granite material is remaining in this area of the Panda/Koala/Beartooth WRSA after quarrying is completed will be reclaimed with the rest of the WRSA.

Jay Quarry

As a contingency for Jay construction, a quarry could be developed within the footprint of the Jay WRSA as an additional source of run-of-mine rockfill for dike construction, if required. The Jay quarry would be completely filled and covered by the construction of the Jay WRSA. If developed, the quarry will become part of the Jay WRSA, and as such, will not require reclamation.

Esker Cut Material Stockpile Esker Cut



Roads

Map 5.8-2 and Table 5.8-3 provide a summary of Ekati mine roads. Roads within the mine area are constructed at different widths depending on their purpose and the type of vehicle they are designed to support. In general, the roads on site are designated as access roads or haul roads. Access roads support light-duty trucks, and include plant site and service roads. Haul roads support large haul trucks and mining equipment and include those roads in mine pits, to and on WRSAs, for ore haulage to the coarse ore handling at the plant site, and the Misery and Sable roads. The widest roads on site are for the landtrain.

For closure, some roads maybe left in place as travel corridors, and if required, road berms will be knocked down to facilitate access and egress by wildlife. Where roads are not left in place, they will be selectively scarified and vegetated to promote natural vegetation.

JAY ROAD

SABLE ROAD

PIGEON ROAD

FALCON ROAD

LYNX ROAD

BEARTOOTH ACCESS ROAD

CAP MAG ROAD

FOX HAUL ROAD

FUTURE PIT RING ROADFUTURE WEST ACCESS ROAD

MISERY ACCESS ROAD

MISERY KING POND ROADMISERY WASTE ROCK ROAD

HAUL ROAD

MISERYMAGAZINE

ROAD

JAY PIPELINE ROAD

JAY NORTH ROAD

LAC DE GRAS TO MISERY ROAD

SABLE DEVELOPMENT

BEARTOOTH/PANDA/KOALA DEVELOPMENT

LONG LAKECONTAINMENT FACILITY

MAIN CAMP

AIRSTRIP

FOX DEVELOPMENT

JAY DEVELOPMENT (FUTURE)

MISERY CAMP

MISERY DEVELOPMENT

LYNX DEVELOPMENT

FUTURE JAY ROADS

MISERY ROAD

LAC DU SAUVAGE

LAC DE GRAS

DUCHESSLAKE

PAUL LAKE

URSULA LAKE

COUNTS LAKE

EXETER LAKE


500000

500000

510000

510000

520000

520000

530000

530000

540000

540000

550000

550000

7160

000

7160

000

7170

000

7170

000

7180

000

7180

000

7190

000

7190

000

PAT

H: I

:\CLI

EN

TS\D

OM

INIO

N\1

7765

30\M

appi

ng\M

XD

\ICR

P\1

7765

30_M

ap5_

8-2_

Eka

tiMin

eRoa

ds.m

xd P

RIN

TED

ON

: 201

8-08

-14

AT: 7

:25:

43 A

M

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT


PROJECT


EKATI MINE ROADS

MAP EXTENT


KEY MAP

0 5,000 10,000

1:175,000 METRES


WINTER ROAD

WATERCOURSE

WATERBODY



FUTURE FOOTPRINT

FUTURE JAY ROAD

ROAD

REFERENCE(S)

1776530 3000 0 5.8-2

2018-08-14

MJ

AB

BW

LN


YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED



Table 5.8-3 Ekati Mine Roads


Access roads • constructed with average 10 m wide surfaces to accommodate two-way traffic for light vehicles • constructed primarily from waste rock excavated during mining • about 78.2 km have been or will be built on site • built on fill where required to insulate the underlying permafrost • safety berms (2 m wide) are added wherever the drop-off exceeds 3 m, and slots are cut periodically to

permit snow removal and accommodate wildlife crossing • culverts are placed where the roads intersect major natural drainages • specific caribou crossings have been constructed in areas of caribou migration

Old Fox Exploration Road • reclaimed road approximately 3 km long that connects the south end of the airstrip to Fox portal • although this road is reclaimed, it may be used in future

Misery Road • a 29.8 km long road that connects Misery facilities to the main plant and camp site • averages 21 m wide • constructed with a minimum fill thickness of 1.8 m (2 m on average) • side slope ratio negates the requirement for safety berms • twelve caribou crossings were strategically placed on the Misery Road

Sable Road • a 17.6 km all-season access road that links the Sable site to Pigeon Road • up to 24 m wide • constructed as a low profile road that minimizes fill heights • two types of culverts are used: an arch culvert at the Pigeon Stream crossing, and round culverts at three

other stream crossings Falcon Road • a 0.5 km road from Falcon Lake to the Sable Road

• Falcon Lake is used for road watering access during Sable Pit operations • Falcon Road is 14 m wide

Pigeon Road • a 6.2 km long all-weather road that connects Pigeon Pit to the main camp

Lynx Road • a short connector road approximately 1 km long by 30 m wide was constructed from Lynx Pit to the existing winter road

• the northern portion of the winter road access from Lac de Gras to Misery Road (as far as Lynx Pit) was resurfaced with granite rock so it is safe for use by mine operating equipment

Lac de Gras to Misery a 1.1 km winter road that provides access from Lac de Gras to Misery Road

Jay Road • a primary access road to Lac du Sauvage that will connect Jay Pit operations to the existing Misery Road, the existing facilities at the Misery site, and the Ekati main camp

• the road was initiated in 2017 under the Early Works Land Use Permit to extend from the Misery site to 30 m of Lac du Sauvage

• esker cut constructed where the Jay Road crosses the esker through a naturally occurring narrow section of the esker and where there is a natural depression in the esker to reduce the effect of the road on the esker; TK and community input used to determine best location

• the road will eventually connect to the south abutment of the Jay Dike and will be approximately 5.1 km long

• a pipe bench will be constructed alongside the Jay Road, where needed • roads with a pipe bench will be approximately 30 m wide • the pipeline routing will follow the road alignment to minimize the Jay Project footprint • the pipe bench will deviate from the Jay Road near KPSF to follow the Jay Pipeline Road alignment • caribou crossings along the majority of the Jay Road, with 1.9 km of caribou crossings over a length of

approximately 2.75 km (approximately 71%)

Jay Pipeline Road • Jay Pipeline Road branches off from the Jay Road just north of KPSF and is approximately 1.8 km long • will connect the Jay Road with the crest of Misery Pit • the road will be used as a platform for the dewatering pipelines

Jay North Road • a road from the Jay Road to the north abutment of the Jay Dike and Jay WRSA, which will be approximately 3.2 km long

• two caribou crossings are planned




Jay haul roads (waste, ore, and haul train)

• haul roads to support Jay Pit operations • will connect Jay Pit with the Jay WRSA • will connect Jay Pit with the Jay Road, and will intersect the ore transfer pad

TK = Traditional Knowledge; KPSF = King Pond Settling Facility; WRSA = waste rock storage area.

Culverts and Bridges

Culverts have been placed in roadways and under the Ekati mine airstrip to divert water (i.e., drainages, streams, and diversion channels) through mine infrastructure. In closure, culverts will be removed and areas will be contoured to allow water to drain freely and connect with the surrounding drainage features. Where required, areas will be stabilized with vegetation or rock to prevent sediment loss.

Currently, two bridges have been constructed at the Ekati mine. Paul Lake Bridge is located approximately 14 km south of the main camp, on the Misery Road and is approximately 25 m long. The Nema-Nero Bridge is located on the Fox haul road, south of the LLCF Outlet Dam and is approximately 43 m long. All bridge infrastructure will be removed and the bridge areas will be contoured to allow water to drain freely and connect with the surrounding drainage features. Where required, areas will be stabilized with vegetation or rock to prevent erosion and sedimentation. Concrete structures/abutments will be left intact where appropriate to minimize disturbance of the existing stream crossings.

Sumps and Collection Ponds

Rain and snowmelt water falls on and collects around roads, camp pads, WRSAs, and related infrastructure around the mine. Sumps and collection ponds have been constructed to collect water and enable pumping to larger water management facilities, such as the LLCF and the KPSF. Table 5.8-4 provides a summary of Ekati mine sumps and collection ponds.

In closure, the liner sumps (if applicable) will be removed and the sumps will be filled with non-PAG waste rock and contoured to drain freely and connect with the surrounding drainage features, as required. The Jay sumps will be submerged at closure.

Table 5.8-4 Ekati Mine Sumps and Collection Ponds


Main Camp sumps • water from the North half of the main camp area drains to Koala Pit • water from the southwest area of the main camp area drains to the West Collection Pond • water from the southeast area of the main camp drains to the East Collection Pond

• water is then directed to the LLCF Panda/Koala Pit sumps • four operational sumps to keep surface water out of pits and underground

• Koala Main Sump is located west of Koala Pit and south of the Panda/Koala/Beartooth WRSA • Panda West Sump is located directly west of Panda Pit • Panda East Sump is located South of Panda Pit • Panda Northwest Sump is located north of Panda Pit between Panda Pit and Beartooth Pit • water is collected in the East and West collection ponds and directed to the LLCF

Fox Pit sumps • two to three sumps to keep water out of Fox Pit during operations • no longer operational and allowed to overflow and enter pit

Racetrack sump water disposal area

• located within the footprint of the CKRSA and was designated for the disposal of excess water that had been decanted from the landfarm

• sump water disposal area (also known as the Racetrack) was closed in September 2006




Contaminated Snow Containment Facility

• located on the western side of the WRSA • bermed and lined engineered facility designed for the containment of hydrocarbon impacted snow and ice • following the spring melt, the hydrocarbon-contaminated sheen floating on the surface of the water is

physically removed. The remaining water is sampled and tested for hydrocarbons. If hydrocarbons remain, the water undergoes further remediation or disposal. If the water is clean, it is pumped into Cell B of the LLCF

Desperation Pond sump • remaining area of Desperation Pond is being utilized as sump with pumping to the KPSF

Jay sumps • Jay mine inflows sump will be located in a natural depression near the crest of Jay Pit and will collect mine inflow (groundwater inflows to the pit and direct precipitation) and will be pumped to the bottom of Misery Pit

• Jay runoff sump will be located in a natural depression near the crest of Jay Pit to collect inflows to the Jay diked area from surrounding catchments and will be pumped to the top of Misery Pit

LLCF = Long Lake Containment Facility; WRSA = waste rock storage area; KPSF = King Pond Settling Facility; CKRSA = coarse kimberlite reject

storage area.

Pipelines and Pump Stations

Pipelines and pump stations support a variety of operations at the Ekati mine and are summarized in Table 5.8-5. Pipelines and pumps stations may be used for dewatering, transportation of slurry, pit flooding, or for potable water. Where purposes and timelines are compatible, pipes may be reused in different locations throughout the life of the mine.

All pipelines and pump stations will be remediated and disposed of accordingly. Final conditions of underlying pads for the pipelines and pump stations will be same as outlined for pads in above section.

Table 5.8-5 Ekati Mine Pipelines and Pump Stations


Central dewatering system

• minewater from Panda/Koala/Beartooth mining area is pumped through a central dewatering system

• central dewatering system bypasses the processing plant and uses an in-line flocculent/coagulant treatment plant for in-line treatment of suspended solids

• pipelines are generally HDPE (12-inch DR9, 18-inch DR11, 24-inch DR11), insulated, and heat traced, where required

Minewater • minewater from open pit mining operations is pumped via pipelines to an authorized location (e.g., LLCF, KPSF) • minewater from Misery Pit is pumped to the KPSF • pipeline from Misery Pit to KPSF has an in-line treatment plant where flocculants and coagulants can be injected

as required • minewater from Fox Pit is pumped via the existing pipeline from Fox Pit through an in-line flocculent/coagulant

treatment plant and discharged to an established location in Cell D of the LLCF • minewater from Lynx Pit is pumped, via pipeline, to Desperation Pond, with further pumping to the KPSF, if

necessary • during Jay operations, pumping stations will be located in the sumps within the diked area; water from the runoff

pumping station will be pumped via pipeline to the surface of Misery Pit, and water from the mine inflows sump will be pumped via pipeline to the bottom of Misery Pit

• pipelines are generally HDPE (12-inch DR9, 18-inch DR11, 24-inch DR11), insulated, and heat traced, where required

Processing plant pipelines

• PK is carried in heat-traced pipeline as a slurry to the LLCF and Beartooth Pit, and in the future to Panda Pit and Koala Pit

• processing plant operations only use recycled water from the LLCF • water is pumped from a heated and insulated pumphouse through a heat-traced pipeline to the raw water

storage tank at the processing plant • pipelines are generally HDPE (12-inch DR9, 18-inch DR11, 24-inch DR11), insulated, and heat traced




Potable water • potable water for domestic consumption is drawn from Grizzly Lake • water is pumped through a 3.3 km long insulated and heat-traced pipeline to a water treatment module at the

main camp; the pumphouse and intake structure at Grizzly Lake • freshwater use for underground operations is piped from a split in the Grizzly pipeline; at present, the piped water

for the underground is used for mixing cement • pipelines are generally HDPE (12-inch DR9, 18-inch DR11, 24-inch DR11)

Pit flooding pipelines • pipelines for pit flooding will be constructed as required • pipelines for pit flooding will be constructed from Ursula Lake to Sable Pit, from Upper Exeter Lake to the Pigeon,

Panda, Koala North, and Koala pits, and from the LLCF to Fox Pit • operational pipelines will be utilized to the extent practicable, including from Lac du Sauvage to Lynx, Misery, and

Jay pits • approximately 34 km of a combination of 18-inch and 24-inch DR11 HDPE pipe is planned to be installed

• dependent on pit flooding timing, 12-inch DR9 pipeline that is existing on site may be reused Bearclaw pipeline • Bearclaw pipeline diverts stream flow / natural runoff around Beartooth Pit from Bearclaw Lake to Upper Panda

Lake • north of Beartooth Pit on a granite crush bed

• associated with the Bearclaw Dam

HDPE = high-density polyethylene; LLCF = Long Lake Containment Facility; PK = processed kimberlite; KPSF = King Pond Settling Facility.

Power Lines

Ekati mine power lines are summarized in Table 5.8-6. In closure, the power line conductors and guy wires will be removed; poles will be pulled or cut at ground level and the above ground pole supports will be removed.

Table 5.8-6 Ekati Mine Power Lines


Ekati central powerhouse to Misery

• a 3-phase 69 kV overhead power line that follows the Misery Road between the Ekati mine main site and Misery Camp

• constructed to power the Misery Accommodations Complex • approximately 30 km long and terminates at the substation at Misery Camp • power to MUG will be from tapping into the line through a skid mounted 69 kV to 15 kV surface main

transformer and installation of armoured 15 kV power cable from the transformer to Misery Pit • cable will be laid out on pipe supports along the ground surface, at the edge of the road • at the pit, the cable will terminate in a 15 kV circuit breaker, and the voltage will be stepped down again by

a 15 kV to 5 kV transformer that would be connected to the Misery fresh air raise

Misery to Jay • a 69 kV overhead power line will be constructed from Misery Camp to the Jay substation to be located near the south abutment of the Jay Dike

• constructed to power the Jay Project support facilities • subject to detailed design, the 69 kV power line alignment is intended to run approximately parallel to the

Jay Road for about 5 km, with supports located approximately 25 to 50 m from the edge of the road on the south side

• access for the power line anticipated to consist of a 5 m width stub road and a 15 m diameter work area at each support location. The stub roads will be constructed from the Jay Road and Jay Pipeline Road to each power line support location, which will be designed approximately 200 m apart parallel and close to the Jay Road

• these stub roads will provide access for construction, inspection, and maintenance of the power line and support structures

Ekati central powerhouse to LLCF Outlet Dam

• a 4,160 V overhead power line approximately 5 km in length supported on wooden poles to power the LLCF water discharge pumps

Ekati central powerhouse to Fox Pit

• a 15 kV overland power line approximately 7 km in length to power the Fox site

LLCF = Long Lake Containment Facility; MUG = Misery Underground.



Mobile Equipment

The mobile fleet is a combination of track mounted (i.e., dozers) and rubber tire mounted (i.e., trucks) equipment that are mostly diesel powered. Other mobile equipment includes drill rigs, loaders, shovels and dozers, underground haul trucks, ancillary equipment such as graders, and emergency and light vehicles used across the site. Currently decommissioned mobile equipment for parts usage is stored on top of the temporary laydown located at the top of the Panda/Koala WRSA. At closure, this equipment cleaned and disposed of in a landfill, or possibly removed off site, if Dominion should determine that it has significant salvage value.


TK highlights the importance of the proper closure and reclamation of buildings and infrastructure given the observation that structures left on the landscape can alter caribou migration patterns (Dedats’eetssa 2016). Based on the goals and principles for the Ekati ICRP, closure objectives were identified specifically for the closure and reclamation of the buildings and infrastructure component. The objectives and criteria of the ICRP relating specifically to reclamation of buildings and infrastructure are presented in Table 5.8-7. An overview of criteria is presented for each objective, with numerical values (where applicable) to be developed for the Final Closure and Reclamation Plan.

Table 5.8-7 Closure Objectives and Criteria for Buildings and Infrastructure

WEMP = Wildlife Effects Monitoring Program.


BI-1 Residual material from demolition does not negatively affect the environment or human health.

Develop and follow decommissioning plan, taking into account potential impacts on the reclaimed environment.

Decommissioning is completed in accordance with the approved decommissioning plan Sites are protected from erosion to a degree that is similar to what is typical of a natural landform Removal of hazardous (i.e. fuel, oils, glycol, batteries) and other materials is documented.

Physical inspection, with signed inspection report

BI-2 Roads left in place are suitable for wildlife movement.

Selectively leave roads and airstrip in place in the context of site-wide wildlife movement.

Targeted facilities are left in place. As-built drawings (construction meets design intent) Routine site-wide monitoring through WEMP

BI-3 Disturbed areas are physically stable and surface drainage patterns are established.

Selectively scarify, grade, and vegetate unstable disturbed areas. Construct channels for drainage, where necessary, or grade/scarify in a manner that encourages drainage. Remove bridges and replace culverts with swales on reclaimed roads.

Targeted areas are scarified and vegetated. Areas of significant ponding are prevented by channelling flow to downstream watershed, with flow occurring through constructed channels if required. Bridges and culverts are removed. Any thermokarst erosion or subsidence is within the limits of what is observed in comparable natural environments.

Physical inspection by a qualified professional during the post-closure monitoring period.

BI-4 Natural vegetation establishment is promoted in disturbed areas.

Selectively scarify and vegetate areas.

Targeted areas are scarified and seeded. As-built drawings (construction meets design intent) Routine vegetation monitoring




Dominion continues to work with the TKEG to better understand caribou movement in and around the site to determine where roads may be left in place at closure to better facilitate safe use of the closed mine area. Concern has been expressed regarding the removal of buildings and infrastructure on site, namely that everything be removed to restore the land to its original state. Some expressed concern that the removal of infrastructure could lead to contamination of the ground and water, and that non-biodegradable waste would be unsafe for animals. Mixed feedback was received regarding the potential for leaving the airstrip in place, with some viewing it as an important piece of survival infrastructure for bush pilots, while others suggested that hunters may take the opportunity to use the airstrip to land and over-hunt wildlife in the area. Feedback from engagement (e.g., the 2018 ICRP workshop and community visits) has suggested that the current road system could be used as a caribou movement corridor similar to an esker. Access and predation were two other main concerns regarding caribou use of roads at the Ekati mine. Participants suggested a number of potential mitigations, including monitoring where caribou are crossing and removing a portion of the road to create a path, or building ramps with appropriately small substrate and width to facilitate going over the road. Conversely, some have suggested that the roads be removed completely, returning the land to its pre-development state.

Feedback regarding the scarification of the road suggested that this was an unnecessary procedure, and that caribou would use the road anyway. Further, it was suggested that design elements that would deter caribou from using the roads as a movement corridor should be avoided. Dominion considered this feedback and re-evaluated the plan for haul road closure, instead focusing on maintaining the roads as safe migration corridors for caribou.


5.8.4.1. Wildlife Movement on Roads

Closure planning to date (e.g., ICRP Version 2.4) has made a simple assumption that all roads will be reclaimed in the same manner. Once a road is no longer required (e.g., for monitoring or to allow access to the reclaimed sites), it will be removed. Safety berms, culverts, and stream crossings (bridges) will be removed, the surface scarified, and then allowed to naturally recolonize with vegetation. It was acknowledged that some sections of road may be considered hazardous to wildlife (e.g., steep roadsides) and would require further evaluation closer to the time of closure.

Currently, the site includes about 141 km of roads. Caribou movement across and along the haul roads has been an ongoing point of concern with community members and a focus of on-site monitoring. For example, during the 2017 Bathurst Caribou Monitoring Program it was suggested that the high banks on the road might be deflecting the migration of the herd, and that caribou that did make it onto the road would often be unable to exit the road for several kilometres. Caribou crossing structures have been established at a number of locations along the Misery and Sable haul roads, and their effectiveness has been evaluated in Caribou Crossing Photo and Road Features Analysis 2011-2015 (ERM 2016d).

Monitoring data and TK are being used by Dominion to evaluate the potential to modify the roads into features that may facilitate wildlife movement in the post-closure landscape. For example, the alternative to scarifying all road surfaces that results in coarse rocky surfaces is to leave road surfaces intact to function in a manner similar to an esker. Feedback from community members indicates that with the provision of sufficient and safe access and egress, a smooth road surface would provide benefits to wildlife, including ease of movement, relief from insects, and connectivity between areas of higher quality habitat.

While there are potential benefits of leaving the road surface intact, applying this approach everywhere could also result in encouraging wildlife toward areas of site that provide poorer quality habitat. In these circumstances, scarifying the road to reduce its attractiveness for movement could be a means of encouraging safe wildlife movement away from the site.



To illustrate how the dual treatment of roads could be applied across the Ekati mine site, Map 5.5-8 depicts sections of Misery and Sable roads that could be reclaimed to function as potential esker complexes (pink sections on the map), facilitating caribou movement by providing access and egress from areas around site with higher quality habitat and demonstrated seasonal presence of caribou (i.e., during fall or spring migration, or post-calving season). Other sections of road are depicted in red (scarified to “boulder association”), indicating that while wildlife movement would not be prevented, it would also not be encouraged. For example, the idea behind ending the esker complex segment to the north of Pigeon Pit is to encourage wildlife movement toward the west in alignment with regional movement patterns, and to discourage movement towards the lower habitat quality associated with the WRSAs to the south. Similarly, the segment of Misery Road south of the Paul Lake Bridge (which will be removed at closure) would be left intact to facilitate movement, while the segment north of the bridge, which goes through low quality habitat, would be scarified.

Decision-making regarding how specific road segments will be reclaimed and the number and location of access points and crossings will be advanced through reclamation research (see Section 5.5.9), ongoing engagement with communities and TK holders (see Section 2.4), and future updates to the ICRP. Once these initial decisions are made, other more detailed design aspects will be considered, such as the optimal slope and grain size for roads identified as potential esker complexes, which will allow safe use of the reclaimed roads and areas by wildlife.



The steps for closure and reclamation of key facility type are described in Table 5.8-8.

Table 5.8-8 Closure Activities for Buildings and Infrastructure at Ekati Mine

Facility Type Closure and Reclamation Measures

Buildings • Clean up and dispose of demolition waste and garbage. • Remove hazardous materials within buildings • Dismantle and demolish buildings. • Break concrete footings to the ground or slab level. • Cover and cap concrete slab with waste rock. • Bury demolition material in landfill. • If Dominion should identify material with significant salvage value, backhaul on winter road.

Fuel tanks • Remove any remaining fuel and product in storage tanks. • Dismantle storage tanks. • Clean tanks of residual material, cut up, and bury in landfill.

Pads (e.g., camps, ore storage) and Airstrip

• Knock down berms on airstrip. • Contour the edges of the pads to physically stabilize and prevent surface erosion. • Selectively scarify and vegetate for physical stabilization and to promote natural vegetation growth. • Selectively place topsoil/till material in lifts or islands. Grade/scarify reclaimed pads in a manner that

promotes drainage, with formation of swales where needed to promote positive drainage.

Airport Esker • Repair any thermokarst erosion or subsidence

Jay Road Esker • Backfill cut with till, granite, or other available non-PAG material to reach elevations and contours that match the surrounding area.

• Cover the backfill with the stockpiled esker material to create a natural-looking landform. • Establish drainage channels. • Scatter boulders to increase surface roughness. • Seed and fertilize with native species as required.

Sumps and collection ponds • Remove residual water. • Remove liners and dispose of them in the on-site landfill. • Backfill depressions with clean non-PAG rock.



Facility Type Closure and Reclamation Measures

Pipelines • Dismantle and dispose of at the on-site landfill, or possibly remove off-site for salvage if Dominion should determine that it has significant value.

• Dismantle and landfill water pump houses. • Leave the Grizzly Lake causeway in place to prevent further disturbance of the lake. • Remove the timber supports and landfill. • Recontour pipe crush gravel pads with adjacent road.

Power lines • Remove power poles and lines and dispose of them in the landfill, or salvage if significant value is identified.

Roads • Develop design on where road surface should be left in place at closure to facilitate wildlife movement. • Knock down berms and construct additional wildlife crossings, if required by design. • Where roads are not designed to be left in place, selectively scarify and vegetate to promote natural

vegetation growth.

Culverts • Remove culverts and dispose in landfill. • Contour swales to allow for drainage and connection to the surrounding watercourses and

waterbodies, as required.

Bridges • Remove bridges and dispose in landfill. • Leave concrete structures/abutments intact to minimize disturbance of the existing stream crossing as

appropriate. • Contour the area around the channel to match the natural topography.

Mobile equipment • Remove hazardous materials from equipment and bury the clean equipment in the landfill or other appropriate location.

• If Dominion should find at the time of closure that the equipment has significant value, transport equipment off-site to point of sale.

non-PAG = non-potentially acid generating.



Progressive Reclamation

Progressive reclamation and monitoring of sites like Old Camp and the Airport Esker provide valuable information about techniques to enhance future reclamation success of buildings and infrastructure at closure.

Information can be gleaned from these sites about decommissioning, demolition, remediation, site preparation, growth media, drainage, and revegetation. More details about the specific progressive reclamation completed to date can be found in Chapter 6 of this document.

Vegetation Substrate Research

Stockpiles of topsoil, till, and lakebed sediment are stored on or adjacent to the Panda/Koala/Beartooth, Fox, and Pigeon WRSAs. There is also a till stockpile planned to be constructed on the Jay WRSA. Locations of these stockpiles are shown in Table 5.5-9 and Figure 5.8-7. This material has been planned for use as a growth medium to support revegetation of pads that are prone to erosion and are targeted for a revegetated cover.



Studies at the Ekati mine that assess substrates include:

• Rock pad reclamation research—assessed the viability of various combinations of CPK, topsoil, lakebed sediment, and glacial till as growth mediums. Results to date show the best growth and survival in topsoil, followed by glacial till. CPK was found to be unsuitable as growth material on its own, while lakebed sediments were effective as a subsoil layer under topsoil.

• Lakebed sediment / glacial till stockpiles—assessed the ability of lakebed sediment and glacial till stockpiles to support vegetation. Results to date show that both materials support grasses, herbs, and shrubs, but that glacial till allowed for greater ingress of native species, whereas lakebed sediment is largely limited to those species that were planted.

A literature review completed by Ecosense (2018) summarizes the potential to use locally available stockpiles of excavated lakebed sediment at Ekati mine as a reclamation substrate to revegetate rock pads or tailings. The literature review indicated that the physical properties of lakebed sediment, its propensity for surface crusting, lack of nutrients, and lack of soil fungi and other biota limit its usefulness as a stand-alone reclamation substrate. The study further indicated that use of topsoil and till stockpiled materials as substrates are a feasible reclamation strategies. Engagement with the TKEG in 2017 has indicated that it is not likely that lakebed sediments will enhance traditional use of the reclaimed landscape. Based on these, findings Dominion plans to prioritize the use stockpiled till and topsoil materials for revegetation rather than lakebed sediment, as the till and topsoil provide more benefits to reclamation.

Dominion plans to conduct further trials to evaluate the use of lakebed sediment as a soil amendment to waste kimberlite either at the CKRSA or Fox WRSA. Research on lakebed sediments is discussed in more detail in Section 5.5.

What’aa Esker Research Project

The What’aa Esker Research Project involved a study in August 2014 by Tłı̨chǫ Elders of varying properties of natural eskers close to Mesa Lake, NWT. A site visit to the Ekati mine with an engineer for the Elders to provide advice on the Jay Road crossing of the esker was also arranged. Discussions outlined key features inherent to the eskers and how caribou use eskers. The key understanding gained from the project was that waste rock piles do not function as eskers. The information gained from the program was deemed to be more valuable when applied to roads around the mine site.

As part of this study, the Tłı̨chǫ identified information that can be used in the planning, construction, and reclamation of roads, and to aid in the continued conservation with Tłı̨chǫ Elders and communities. The draft What’aa Esker Research Report (Chocolate 2015) provided the following recommendations that could be applied to road reclamation at Ekati:

• Eskers near water better support wildlife but the benefits from building near water-bodies will have to be weighed against the risks of water contamiantion.

• Openings in the slope allow for the creation of dens for wildlife. Wildlife dens are a common feature on eskers.

• Lichens, berries, and grasses are vegetation types preferred by wildlife, especially caribou.

• The height of an esker is not as important as the smoothness of the terrain.

• Large boulders and rocky terrain that could impede or injure caribou must not be used. Filling and covering gaps and crevasses could correct this.

• Sandy surfaces are preferred by both Tłı̨chǫ and caribou travelling over eskers.




Decommissioning and Demolition (BI-1)

To meet the objective that residual materials from demolition do not negatively affect the environment or human health, the decommissioning and demolition approach for each facility follows the same basic sequence of events as summarized in Table 5.8-9.

Table 5.8-9 Decommissioning and Demolition Approach

Item Task Description

1 Cut/remove of utilities from the building

Remove electrical, fuel lines, sanitary sewer, water, data cables, and telephones.

2 Remove interior contents Remove internal contents of infrastructure. This could be furniture and interior finishes in the case of buildings, or liquids in the case of tanks or pipelines.

3 Remove hazardous materials Remove hazardous materials in buildings, tanks, or pipelines

4 Structural demolition or dismantling to grade

Dismantle buildings and deposit waste materials in landfill. Cut up tanks for burial in landfill or other appropriate location. Dismantle pipelines for disposal in on-site landfill. If Dominion identifies materials with significant salvage value, separate and backhaul salvage material down the winter road.

5 Breaking concrete slabs and cut piles Break or bury concrete footings to the ground or slab level. Cut piles at ground level. If required, bury concrete pieces.

6 Final clean up Remove any remaining demolition waste for appropriate disposal.

7 Post-reclamation report and reporting Complete necessary performance evaluation reporting and any monitoring requirements.

8 Relinquishment Return of security for completed demolition.

Decommissioning and demolition will generate a variety of hazardous and non-hazardous waste streams. Waste generated will be handled in accordance with site-wide Waste Management Plan. The objective of the Waste Management Plan is to maintain a safe and healthy workplace at the Ekati mine and ensure that potential adverse effects to the environment and wildlife are minimized through sound waste management practices. The plan provides clear direction to Dominion staff, contractors, and stakeholders on how waste from the Ekati mine is managed through each of the waste streams to final disposal. Waste streams and general management practice include the following:

• Landfill waste—Inert waste materials from demolished structures (steel, wood and plastic) will be deposited in demolotion landfill

• Oil and filters—Waste oils will be collected across the site in labelled containers. Oil filters will be drained to remove the contents, and the filters will be transferred to dedicated containers. The filters will then be shipped for off-site disposal. Air filters generated at site will be deposited in the landfill.

• Waste glycol—Waste glycol generated from tank decommisioning will be collected in dedicated containers and shipped for off-site disposal.

• Batteries—Automotive batteries will be placed into suitable containers for shipping from site to an approved disposal/recycling facility. Small disposable batteries (e.g., AAs, Cs) will be collected in dedicated containers, placed into a larger container, for off-site disposal.

• Biohazardous material—Biohazardous materials (e.g., razors, syringes) will be handled properly and disposed of accordingly.

• Hydrocarbon materials—Remediation procedures are discussed in Section 5.2.3.



During closure, waste material will be sent to the existing landfill, a new demolition landfill, or another approved location. The Ekati mine has a landfill that only accepts inert, non-hazardous wastes such as clean wood and plastic. The landfill is managed according to the Landfill Management Plan. The objective of the plan is to prevent waste from entering the landfill that may attract or be harmful to wildlife or the environment. The plan is a component of the Waste Management Plan. An estimate of demolition waste volume will be developed closure to final closure. Additional deposition locations for inert solid waste will be identified for WLWB approval in future ICRPs. If material with significant salvage value is identified by Dominion, that material will be removed off-site by backhauling on the winter road.

Wildlife Movement (BI-2)

Following the completion of closure works, roads, pads, laydowns, and airstrip will be suitable to facilitate wildlife movement. Decision-making regarding how specific road segments will be reclaimed and the number and location of access points and crossings will be advanced through reclamation research, ongoing engagement with communities and TK holders, and future updates to the ICRP. Once these initial decisions are made, other more detailed design aspects will be considered, such as the optimal slope and grain size for roads identified as potential esker complexes, which will allow safe use of the reclaimed roads and areas by wildlife. Proposed final designs for the road network will be submitted to the WLWB for review and approval prior to undertaking final closure activities.

Physical Stabilization and Drainage (BI-3)

In general, it is anticipated that physical stability and safe drainage will be primarily achieved with the following typical engineering measures:

• Remove culverts and replace with swales on reclaimed roads.

• Contour sites to stable, irregular landforms that channel drainage and resist excessive erosion through targeted slope angles, slope lengths, and the creation of meso- and micro-topography.

• Selectively scarify and vegetate areas in a manner that prevents erosion and promotes drainage.

An assessment of the site conditions could result in the selective need for additional measures including the following:

• Construct small drainage channels through reclaimed pads, where necessary, to promote drainage and minimize erosion.

• Install erosion protection on reconnected channels (e.g., rip rap or revegetation).

• Place a topsoil/till layer to promote vegetation growth.

• Install temporary berms, sediment fences, or wattles, as required.

Natural Revegetation (BI-4)

Natural revegetation will be encouraged by creating conditions that are conducive to seed ingress, retention, germination, and survival. Natural ingress of vegetation can be encouraged by:

• Creating an irregular surface that will be more likely to catch and hold seed through mounding, surface roughening, scarifying, ripping, placement of boulders or rock piles, or placement of woody debris, if available.



• Creating a surface that is suitable for seed germination and growth through establishing proper drainage to prevent ponding and/or excessive water loss, decompacting soils to allow for root penetration, and placing topsoil/till where required to improve soil texture, nutrition, or moisture holding capacity.


The techniques and approaches for closure and reclamation of infrastructure and related components of mine sites is relatively well defined and is subject to a much lower degree of uncertainty as compared to other aspects of closure. One reclamation uncertainty and a summary of how it will be addressed through reclamation research plans and monitoring is provided in Table 5.8-10. The referenced research plan is provided in Appendix E.

Table 5.8-10 Buildings and Infrastructure Closure Uncertainties


When and where will roads left in place be suitable to facilitate wildlife movement through the site RP 1 – Wildlife Safety

RP = research plan.

Engineering designs for the closure of the buildings and infrastructure component will continue to be refined until implementation of closure works. As such, the basis for estimates and analyses include engineering judgement. Additional design work is planned to address key assumptions and reduce relevant uncertainties.

The collection of additional monitoring data during operations will refine the closure and reclamation planning, but this is not an uncertainty that would be managed through a research program.


The post-closure monitoring program for the buildings and infrastructure mine component will be adapted from the current monitoring programs at the Ekati mine adjusted to suit specific closure needs. Indicators for monitoring effectiveness of reclamation activities for the buildings and infrastructure component are described in Table 5.8-7.

For Objective BI-1, sites will be inspected to ensure that demolition waste is removed. Phase 1 and 2 site assessments will be used, as required to confirm that remediation has been completed to regulatory standards.

For Objective BI-2, sites will be inspected to ensure that targeted roads are left in place and are suitable for wildlife movement.

For Objective BI-3, reclaimed landforms will be periodically monitored by an engineer to record erosion or subsidence and determine if remedial measures should be undertaken. If required, observed localized instabilities will addressed through preventative maintenance.

For Objective BI-4, sites will be inspected after reclamation and will be regularly monitored until closure criteria are met. If required, additional contouring, vegetation, or fertilization may be undertaken.





Residual effects related to the successful completion of the closure works for the buildings and infrastructure mine components are limited. The residual effects are expected to include land use effects for wildlife and human use. There will be a permanent visual effect with some roads and pads remaining on the landscape at closure; this may affect the use of the land for traditional activities, such as hunting and fishing. Some roads and the airstrip at the Ekati mine will represent a permanent modification of terrestrial habitat. These corridors will change vegetation types and topography on the closure landscape, and are expected to provide new corridors that wildlife can safely access and egress, but may impede existing travel corridors.

These are consistent with the findings from previous EAs (BHP and Dia Met 1995, 2000; DDEC 2013d, 2014a) and ICRP Version 2.4 (BHP Billiton 2011a).

5.8.9. Residual Risks and Contingencies

The closure and reclamation of infrastructure and related components of mine sites is subject to a much lower degree of uncertainty as compared to other aspects of closure. The techniques and approaches are relatively standard, and have been demonstrated to be reliable and effective at many sites around the world. Due to the lower uncertainty, specific contingencies are not defined for this component.

Nevertheless, in the case of unforeseen events, the principles of adaptive management, which have been applied at the Ekati mine since mine development began in 1997, would underpin the approach to any unanticipated contingencies.

Closed and reclaimed areas may be subject to greater erosion that predicted in the design stage. This is considered a monitoring and maintenance issue (as discussed in a previous section), and is not addressed here with a specific contingency plan.



Progressive Reclamation

6.1. Definition of Progressive Reclamation

Per the Closure Guidelines (MVLWB 2013), the definition of progressive reclamation is as follows:

Progressive reclamation takes place prior to permanent closure to reclaim components and/or decommission facilities that no longer serve a purpose. These activities can be completed during operations with the available resources to reduce future reclamation costs, minimize the duration of environmental exposure, and enhance environmental protection. Progressive reclamation may shorten the time for achieving closure objectives and may provide valuable experience on the effectiveness of certain measures that might be implemented during permanent closure.

Progressive reclamation may be undertaken where beneficial use of the operational resources available at the Ekati mine can allow the work to be conducted more efficiently and where the work will lead to reduction of financial security. Progressive reclamation activities are scheduled for mine areas where there is no potential for future benefits or business opportunities or in areas where there is a need to mitigate current environmental or safety risks.

Mine areas that have no future business value or that represent current environmental or safety risks are evaluated for progressive reclamation. Reclamation of selected areas will continue throughout the LOM. Detailed closure plans for the relinquishment of progressive reclamation areas will be submitted to the WLWB for review and approval, as necessary.

Opportunities for progressive reclamation will be evaluated on a case-by-case basis. The evaluation of opportunities will consider potential future values and immediate environmental risks. As part of the evaluation process, community input and TK will be considered in the decision making. Progressive reclamation projects are generally completed in stages, with the design being refined as the results of the previous phases are available. After each phase, the risks to the site and to the value of further investment are re-evaluated combined with community and TK to help determine how progressive reclamation projects are prioritized moving forward.

6.2. Opportunities for Progressive Reclamation

As operations proceed and the mine plan evolves, the areas chosen for progressive reclamation, and the order in which they are reclaimed, may be modified due to:

• potential for new projects that may reuse existing disturbed areas

• optimization of mine plans that change mining and processing plans, development schedules, or landform designs

• opportunities to resuse existing facilites and reduce the overall mine footprint

• determination of areas where early reclamation will aid in environmental protection measures (e.g., erosion or seepage control)

• evaluation of the risk and cost for each reclamation project

• the value of the resource

• input from community engagement and TK

• cost efficiencies in infrastructure development, mining, and reclamation operations

• procedures for corresponding reduction in security



Once it is determined that completed areas or landforms are available for progressive reclamation, the completion of reclamation activities occurs as a progressive action throughout the active operating stage of the mine. Progressive reclamation sites may serve as a learning experience, providing opportunities to test, monitor, and adapt reclamation strategies.

The planned areas of progressive reclamation based on the 2018 Ekati LOM Plan are described below.

Long Lake Containment Facility

Reclamation research has been underway at Cell B of the LLCF since 2012 when FPK deposition ceased in the upper areas of Cell B (Section 5.6.1.2). The research studies are intended to define the detailed procedures for final reclamation of Cells A, B, and C. Following f

Dominion's commitments through the Jay Project EA review, research studies will continue at the LLCF and will transition to reclamation of completed areas as the study results provide final definition of reclamation procedures. The planned transition of FPK deposition from the LLCF as primary PKCA to the Panda/Koala pits as the primary PKCA may facilitate progressive reclamation at the LLCF by providing additional suitable areas.

Based on the 2018 LOM Plan, it is expected that Cells A, B, and C of the existing LLCF can be progressively reclaimed during Jay Pit mining. The overall reclamation goal for the LLCF is to design and construct a long-term cover that will physically stabilize the PK with a landscape that will be safe for human and wildlife use. Dominion has also sought TK input into the plans for the progressive reclamation of the LLCF. This has involved site visits, including from Kugluktuk Elders to provide input into the vegetation trials based on their experience in estuarine environments.

The closure of these facilities will proceed as described in Section 5.6.

Open Pits

Several of the open pits at the Ekati mine are potential candidates for progressive reclamation. Operational activities such as depositing PK or minewater into selected pits may also reduce the volume of water required for back-flooding, thereby reducing the timeline to complete the closure activities, but negate the opportunity for progressive reclamation while the operational use is underway. As discussed in Section 5.3.5, back-flooding activities include passive (precipitation and natural runoff) or active (pumping from a nearby lake or site facility) means of filling the pit. Under the current mine plan, the principal progressive closure candidates are as follows:

• Pigeon Pit—Back-flooding of Pigeon Pit will be prioritized to minimize the oxidation of exposed metasediment in the pit walls after open-pit mining operations have ceased. Following the completion of mining, passive flooding will occur until commencement of active back-flooding using water extracted from Upper Exeter Lake. Pigeon Pit is expected to be the first pit to be fully reclaimed during Ekati mine operations. As such, it is expected to provide an opportunity for research and learning to support refinement of the reclamation and closure plans at the other pits.

• Lynx Pit—Closure and reclamation of Lynx Pit will be completed as per Section 5.3. After mining is completed, there is a period during which Lynx Pit will be used for minewater management. This will include management of minewater from the MUG operation and from the KPSF. Once MUG mining is completed, Lynx Pit will be pumped out to start flooding the MUG developments and Misery Pit. The MUG project will be completed ahead of final dewatering of the Jay diked area, and, following the use of Lynx Pit for minewater management, the pit will be partially filled with Lac du Sauvage water with elevated TSS from the final dewatering of the Jay diked area. The rest of the pit will be filled using natural precipitation and surface water inflow, and allowing the TSS to settle prior to Lynx Pit Lake naturally discharging to Lac de Gras. The use of Lynx Pit to store TSS-laden water from the Jay diked area will minimize the pumping requirements and move forward the reclamation of the pit.



• Sable Pit—Following the completion of mining at Sable Pit and while mining of Jay Pit is ongoing, passive back-flooding will take place until the commencement of active flooding with water from Ursula Lake. This active back-flooding is expected to continue through the last years of mine life and into the final closure period.

• Beartooth Pit—As described in Section 5.3, the ongoing placement of FPK in the pit will reduce the pumping requirements at closure. Active back-flooding of Beartooth Pit is expected to be completed prior to final closure of the site.

• Fox Pit—Mining at Fox Pit has been completed, and passive flooding is taking place. This is expected to be followed by a period of active back-flooding, with water pumped from the LLCF, while mining is occurring at other areas. This active back-flooding is expected to continue through the last years of mine life, and into the final closure period.

• Panda, Koala, and Koala North pits—Placement of PK into these pits and underground workings will take place during Ekati mine operations, which will reduce the pumping requirements at closure. Freshwater cap back-flooding and final reclamation will not take place until final closure.

Waste Rock Storage Areas

Wherever possible, WRSAs will be constructed in their final configuration to enhance long-term stability of structures and avoid rehandling of materials. Progressive reclamation of WRSAs will involve conducting closure activities with consideration for how wildlife are likely to move through site. Dominion has received feedback that it is important to consider the overall closure strategy for mine components in the context of site-wide wildlife movement. In the case of WRSAs, locations for the placement of access ramps may be targeted at specific WRSAs, along potential caribou movement paths.

Where access ramps are to be built, the locations and design will be defined based on engagement with local communities and their understanding of caribou migration paths, as well as observations made at the site prior to and during operations. Depending on the WRSA(s) selected through the engagement process, ramps may be built once the WRSA is no longer operational, but before the full closure of the Ekati mine.

6.3. Progressive Reclamation Activities

Dominion has been conducting progressive reclamation at areas no longer part of active operations at the Ekati mine since the start of mining in 1995, in support of the reclamation goals for the mine. The progressive reclamation activities provided experience that is valuable for planning reclamation and closure of the major mine area components. An overarching lesson has been the importance of treating closure and reclamation activities as projects, integrated into mining operations. A staged process to closure and reclamation work allows the progressive refinement of design concepts, cost estimates, and staged decision making with respect to which projects move forward and when.

A summary of the annual reclamation reports provided to the WLWB for the Ekati mine between the submission of Version 2.4 of the ICRP (BHP Billiton 2011a) and this version of the ICRP is provided in Table 6.3-1. These reports summarize progress on progressive reclamation at the Ekati mine, as well as research and monitoring programs that support ongoing closure and reclamation planning. A summary of key completed Ekati mine reclamation activities and lessons learned since the start of mining is provided below. Further examples of lessons learned are presented in Appendix D.



Table 6.3-1 Annual Reclamation Research Reports

Report Key Progressive Reclamation Contents Progress

2012 Annual ICRP Progress Report (BHP Billiton 2012)

PDC stabilization • Phase II slope stabilization completed • benched the west side between Stations 2+115 and 1+760

Ongoing research including vegetation research in LLCF

• water quality, permafrost growth • planning for LLCF pilot study

Pigeon Stream diversion • construction, topsoil placement, and seeding

Revegetation monitoring • ongoing reclamation and monitoring of various reclaimed sites

2013 Closure and Reclamation Progress Report (DDEC 2013c)

Koala Underground reclamation • completion of four underground areas

LLCF closure landscape (Appendix C of DDEC 2013c)

• vegetation rock plots established

Pigeon Stream diversion • planting of seedlings

Revegetation monitoring • ongoing reclamation and monitoring of various reclaimed sites

2014 Closure and Reclamation Progress Report (DDEC 2014e)

Old Camp reclamation • Closure and Reclamation Plan approved • Phase II South Pond reclamation completed in 2014

Panda Diversion slope stabilization • Phase III slope stabilization completed • benched the remaining east side between Stations 1+700 and 2+150

Koala Underground reclamation • reclamation of two underground areas

LLCF closure landscape • vegetation rock plots established

Pigeon Stream diversion • planting of wet-tundra seedlings

Revegetation monitoring (Appendix D of DDEC 2014e)

• ongoing reclamation and monitoring of various reclaimed sites

2015 Closure and Reclamation Progress Report (DDEC 2015b)

Old Camp Reclamation • construction of a channel to route surface flow through the reclaimed area

• Phase III environmental site assessment • grading and debris clean up • water quality monitoring (Appendix G of DDEC 2015b)

Panda Diversion slope stabilization performance assessment (Appendix J of DDEC 2015b)

• assessment of PDC stabilization against the closure objectives and criteria outlined for dams, dikes, and channels

Koala Underground reclamation • reclamation of three underground areas

Revegetation monitoring (Appendix F of DDEC 2015b)


2016 Closure and Reclamation Progress Report (DDEC 2016d)

Old Camp reclamation • reclamation monitoring results • water quality monitoring (Appendix J of DDEC 2016d)

Pigeon Stream diversion • revegetation monitoring results

Panda Diversion reclamation monitoring (Appendix K of DDEC 2016d)

• stabilization zone inspection

LLCF reclamation research (Appendix F of DDEC 2016d)

• trial channel construction and bioengineering • seeding • monitoring natural colonization • species trials • harvesting indigenous mycorrhiza • compost trials • soil amendment trials • till top dressing trials • seed collection • natural colonization • vegetation rock plot monitoring • annual crop trials • metals uptake analysis



Report Key Progressive Reclamation Contents Progress

Koala Underground reclamation • ongoing progressive reclamation

Revegetation monitoring (Appendix I of DDEC 2016d)


2017 Closure and Reclamation Progress Report (Dominion 2018e)

Beartooth Pit bathymetric survey (Appendix D of Dominion 2018e)

• assessment of PK volume and pit capacity • assessment of pit water quality

Old Camp reclamation (Appendix I of Dominion 2018e)

• reclamation monitoring results

LLCF reclamation research (Appendix F of Dominion 2018e)

• vegetation rock plots • species trials • annual crop trials • soil amendment trials • till top dressing • seed collection • natural colonization

Revegetation monitoring (Appendix G of Dominion 2018e)


ICRP = Interim Closure and Reclamation Plan; PDC = Panda Diversion Channel; LLCF = Long Lake Containment Facility; PK = processed kimberlite.

6.3.1. Old Camp Reclamation

The Old Camp Closure and Reclamation Plan (DDEC 2013e) was submitted to the WLWB in December 2013 and approved by the WLWB in April 2014 (WLWB 2014). An updated Phase III EA was completed for the Old Camp pad area. In 2017, Dominion completed the remaining reclamation activities of the Old Camp pad outlined in the Old Camp Closure and Reclamation Plan, including the removal of hydrocarbon contaminated soil, reclamation of the pad surface to prevent surface erosion and encourage natural revegetation, and water quality monitoring.

The Old Camp pad contained seven areas of potential environmental concern related to hydrocarbon-impacted materials that were excavated and hauled to the Ekati mine landfarm for bioremediation. About 2,100 m3 of material was removed from the Old Camp pad area. The excavations were backfilled with clean fill from nearby stockpiles.

Reclamation landscaping activities were undertaken at Old Camp with the goal of creating a stable landscape and to leave the site in a state conducive to natural colonization by native vegetation. Activities completed at the Old Camp pad and Phase 1 Pond (Phase 1 PKCA) included:

• pond dewatering, PK removal (hauled to the CKRSA), liner removal (hauled to the main camp landfill), and breaching of the south berm

• constructing a shallow channel to route surface flow through the reclaimed area

• recontouring to prevent surface erosion and encourage natural revegetation

• redistributing salvaged surface soil on accessible slopes where accelerated vegetation establishment will reduce the risk of erosion

• scarifying the surface to about 30 cm to create a rough and loose landscape that alleviates compaction and promotes natural revegetation (Photo 6.3-1)

• mounding of side slopes to mitigate erosion (Photo 6.3-2)

• removing visible debris and construction waste



It is anticipated that these actions will promote natural colonization by tundra vegetation from the surrounding undisturbed areas. No additional seeding or erosion control measures are anticipated.

Source: Dominion 2018e.

Photo 6.3-1 Old Camp Pad Following Scarification

Source: Dominion 2018e.

Photo 6.3-2 Mounding along the Side Slope at Old Camp

Pre-disturbance, the Phase 1 PKCA was the Phase 1 Pond. The pond was located in a natural draw, receiving surface runoff from a catchment area to the northeast of the pond. The catchment area is 18.1 ha. The natural drainage runs in a southwesterly direction and discharges into a small lowland area flowing into Larry Lake. Organic deposits and a shallow wetland area are located northwest of Larry Lake, just south of the Phase 1 Pond. During its operating life, this PKCA included a kimberlite beach, pond, and dam.



A final closure plan for the Phase 1 PKCA was submitted in December 2013 as part of the Old Camp Closure and Reclamation Plan (DDEC 2013e). As part of this submission, five options were evaluated and scored based on long-term drainage and physical stability, long-term water quality, and constructability criteria. The option “North and South Pond Excavation” was selected as the preferred reclamation option (Option 2[b]; DDEC 2013e). This option required the removal of wastes from both the North and South ponds. In addition, grading and contouring activities after excavation would be completed to provide natural drainage through reclaimed channels in the former North and South ponds; the natural drainage is expected to flow from a lowland discharge area (below the South Pond) and into Larry Lake. The option was selected because it would allow a natural drainage path and long-term care maintenance requirements would be limited. A detailed design of this preferred option was completed and is included in Appendix B of the Old Camp Closure and Reclamation Plan (DDEC 2013e).

The WLWB approved the Old Camp Closure and Reclamation Plan in April 2014 with the following conditions applicable to the Phase 1 PKCA monitoring:

• Demonstrate that closure criteria related to water quality were achieved, either in the reclamation completion report or subsequent performance assessment reports.

• Continue post-closure monitoring at the Old Camp Closure and Reclamation Plan site until closure criteria related to water quality are achieved.

• Provide a summary of the water sampling protocol, including the frequency and results of sampling for TSS at the Phase 1 PKCA site during reclamation, in the reclamation completion report.

Progressive reclamation of the Phase 1 PKCA began in 2014 and was completed in 2017. The original pond was constructed with a division into two portions, the South Pond lined with a reinforced polyethylene liner and the unlined North Pond. Reclamation activities for the Phase 1 South and North ponds included excavation and removal of the PK and liner materials from the ponds and grading to promote positive drainage through the excavated areas. The waste rock and sediment materials were placed into the Panda/Koala WRSA, PK was disposed of in the LLCF, and the liner materials were disposed at the landfill. A channel to route water through the reclaimed Phase 1 Pond, along with minor grading to promote positive drainage, and cleaning of debris, was also completed in 2015.

Water quality monitoring of the Phase 1 Pond in 2015 indicated water samples were in compliance with the current Water Licence (W2012L2-0001) effluent criteria, with the exception of TSS at freshet (DDEC 2015b). Water quality monitoring conducted in 2016 and 2017 in the pond indicated that arsenic and aluminum were elevated in comparison to effluent criteria (DDEC 2016d; Dominion 2018e). Water quality monitoring will be continued in the reclaimed water channel with the focus on arsenic and aluminum. Monitoring results will be used to evaluate the need for the implementation of additional water quality mitigation efforts.

Reclamation of the Phase 1 PKCA has now been completed, with post-reclamation monitoring ongoing as described below. The current reclaimed status of the Phase 1 PKCA is shown in Photo 6.3-3.



Photo 6.3-3 Current Reclaimed Status of the Phase 1 Processed Kimberlite Containment Area

Phase 1 PKCA Post-closure Monitoring and Maintenance

The ongoing monitoring and maintenance for the closed and reclaimed Phase 1 PKCA includes the following:

• Water quality monitoring within the constructed drainage channel will be conducted twice per year, once during spring freshet, and again in late summer or fall. (In 2017, samples were collected at the north outlet and south inlet, as well as in the collection trench at the capped North Pond, and in the Larry Lake receiving environment). The results of the monitoring will be analyzed to confirm that water quality continues to be stable. If water quality monitoring results suggest that change in monitoring is necessary, an adaptive management strategy will be used to evaluate needs for adjusting the frequency or locations for monitoring. Additional water quality monitoring may be completed within Larry Lake or other specific locations, if required.

• Regular inspections of the facility will be completed. These inspections will be used to identify whether there are areas of concern developing over time, such as signs of significant erosion, subsidence, slope failures, or surface instability. The inspections will also be used to confirm that proper water drainage conditions have been established and water is being channelled through the reclaimed facility. When required, maintenance will be completed to fix any issues identified during routine inspections.

• Vegetation monitoring data will be collected within the reclaimed areas to evaluate the rate of natural colonization and percent ground cover by plant litter.

Airstrip

Reclaimed South Pond

Reclaimed North Pond

Surface Flow to Larry Lake

Drainage Channel



As part of the reclamation monitoring, Dominion will continue to complete monitoring of water quality performance in the reclaimed water channel. Monitoring results will be used to evaluate the need for the implementation of any water quality mitigation efforts. This evaluation will include analysis of historical water quality variables of interest including arsenic and aluminum. Annual updates of monitoring activities and collected data are (and will continue to be) provided as part of the annual closure and reclamation progress reports. The most recent report (Dominion 2018e) included the results of the water quality monitoring within the constructed channel at the reclaimed Phase 1 Pond.

A performance assessment report will be provided when the monitoring data have demonstrated that the site has achieved closure objectives.

6.3.2. Panda Diversion Channel Slope Stabilization

The PDC is a 3.3 km long channel that diverts flows from the Panda and Grizzly Lake watersheds around mining activities and into Kodiak Lake. The PDC was built in 1997 under the Ekati mine Fisheries Act Authorization SCA96021 to compensate for the harmful alteration of lake and stream habitat where the Panda and Koala pits and WRSAs have been developed.

Construction work began in 2011 to stabilize portions of the channel noted as potentially having long-term instability issues and potentially affecting fish habitat. Slope stabilization of the PDC was done in three phases and was completed in 2014 (Tetra Tech EBA 2014b). After construction, erosion protection and waste rock fillets were placed, and sediment control berms were constructed, where required. Following completion of the works, there has been a period of ongoing monitoring which shows that the stabilization works are performing acceptably. A final construction report (Tetra Tech EBA 2014b) for the slope stabilization project was submitted to the WLWB under Part F Item 8 of Water Licence W2012L2-0001. This report documents the background and construction history of the PDC slope stabilization project, reviews construction methods, and contains interim construction reports for all three phases. As per Water Licence requirements, the report was prepared by a Professional Engineer. A performance assessment report was developed for the PDC sloped stabilization work (included in DDEC 2015b, Appendix J), and Dominion is now in the process with DFO of closing out the financial assurance.

Monitoring has also taken place to confirm that the PDC was providing functional fish habitat as required under the Fisheries Act Authorization. Monitoring was completed between 1998 and 2011, and additional fish habitat enhancement activities (i.e., instream vegetation and rock habitat structure additions) were completed between 2011 and 2014, along with the resloping of the steeper, canyon-like banks. As a result, the Ekati mine’s fish and fish habitat monitoring commitments under the Authorization are considered fulfilled by DFO.

6.3.3. Panda, Koala, and Koala North Underground Closure

Dominion works to progressively reclaim areas of underground facilities as they are no longer required for operations. To date, progressive reclamation activities have been undertaken at Panda, Koala, and Koala North undergrounds. A summary of the progressive reclamation activities undertaken in the undergrounds is as follows:

• Hazardous materials were removed from the underground level and sent to landfills, WRSAs, or off site per the Ekati mine Waste Management Plan. Hazardous materials include fuel, oils, glycols, batteries, explosives, and electrical transformers.

• Removal of all debris and garbage that would be likely to float after flooding of the underground workings was completed.

• Materials considered to have salvageable value to Dominion were removed. These materials could include pipes, cables, electrical gear, or any other fixed materials.



• Temporary barricades to control access were installed.

Progressive reclamation is ongoing. Dominion anticipates having the pits available for PK deposition, with progressive reclamation activities completed leading up to the end of operations and afterwards. The progressive reclamation activities will be documented with final approval by the Mines Inspector before the deposition of PK begins.

6.3.4. Exploration Camp Decommissioning

Mark’s Camp was located about 0.5 km south of the Koala Camp (Old Camp), and was used as a temporary winter camp for exploratory drilling operations between 1993 and 1994. It was moved to the Old Camp location in 1994 and the site was reclaimed. Culvert Camp was a temporary camp constructed in the winter of 1997 to hold overflow from Old Camp, and included approximately six trailers and a 500 L fuel tank and was reclaimed in 1998. Boxcar Camp was a mobile camp located on the shores of Paul Lake. The camp was operational during winter months for exploration. The infrastructure was removed on the 2005 winter road and the remainder of the site reclaimed in the summer of 2005. Norm’s Camp (constructed in 1991) is located on the west shore of Upper Exeter Lake. The airstrip that supplied the camp was operational until 2001 when it was closed to all traffic and markers were placed to indicate that the airstrip was decommissioned. The ownership of this camp was transferred in 2010 and it is no longer part of the Ekati mine Land Use Permits.

The reclamation requirements of exploration camps are covered under Land Use Permits, where reclamation activities and successful completion of reclamation is monitored and signed off by the GNWT (formerly INAC) inspector under the requirements of these Land Use Permits. Mark’s Camp and Culvert Camp have been reclaimed under the requirements of the Ekati mine Land Use Permits. An inspector from INAC visited the Boxcar Camp site to verify that it had been reclaimed.

6.3.5. Long Lake Containment Facility Stabilization

Considerable feedback has been received today through community engagement activities. Concern has been expressed, in particular, about the need to remove waste stored in the LLCF, and the ability of vegetation to re-establish post-closure. Community members have suggested that studies be undertaken to determine what plant species can be effectively grown on kimberlite, and that the community be involved. To this end, LLCF research continues to actively incorporate community involvement and engagement with community members and TK holders. This involvement will continue to be integral in developing the final stabilization cover for the LLCF. Section 5.6.5.2 describes projects undertaken by Dominion to involve communities in LLCF research, and to solicit feedback on closure approach and desired outcomes. The Kugluktuk Traditional Knowledge Program, community student participation, and the 2013 vegetation workshops were all opportunities for communities to provide feedback on PKCA closure approach and activities.

The primary focus of progressive reclamation of the LLCF has been stabilization of the PK surface, with the establishment of large-scale vegetation and water management research areas and the continued natural colonization of vegetation within Cell B to speed the establishment of the physical stabilization cover system. In addition to the revegetation research that has been conducted in the LLCF, a native northern alkali grass (Puccinellia borealis, also known as “goose grass”) from the surrounding tundra began colonizing the west side of the Cell B beaches in approximately 2004. Field observations indicated that natural colonization of goose grass continues to spread past the water boundary running north–south along the west side of Cell B. LLCF reclamation research areas located on the northeast side of Cell B have contributed to the overall biomass growth within Cell B of the LLCF and also serve as an important source of seed for colonization of vegetation within Cell B.



Cell B vegetation growth and the rates of colonization have been evaluated using satellite imagery and the Normalized Difference Vegetation Index (NDVI). Figure 6.3-1 provides a comparison of the 2014, 2015, and 2016 NDVI analysis. In general, an overall increase in the rate of natural colonization from goose grass was observed along the east side of Cell B with major gains forming a beltline with the western border. Lower biomass growth has increased by 54.7% when comparing NDVI data from 2015 to satellite imagery data from 2016. The increased natural colonization levels between 2014, 2015, and 2016 can be seen in Table 6.3-2.

Figure 6.3-1 2014 to 2016 Normalized Difference Vegetation Index Satellite Imagery Analysis

Table 6.3-2 2014 to 2016 Normalized Difference Vegetation Index Satellite Imagery Analysis Results

Percent Change (%)

2014 2015 2016 2015–2016

Lower biomass 5.7 6.4 9.9 54.7

Higher biomass 5.7 5.5 6.0 9.1

6.3.6. Pigeon Stream Diversion Vegetation

The PSD was constructed to divert water from Pigeon Pond and those sections of Pigeon Stream affected by the development of Pigeon Pit. The PSD is a 376 m long lined channel, about 3 m wide by 50 cm deep, bordered by 4 to 6 m of rock crush that is also underlain by a liner. Since construction of the PSD was completed in spring 2012, considerable effort has been directed towards revegetating its banks to ensure their long-term stability.



In the fall of 2012, topsoil hauled from the Beartooth topsoil stockpile, mixed with lake sediment and glacial till (salvaged from the Beartooth Pit development), was placed at three locations on rock crush along the south bank of the constructed channel. The topsoil material was placed with depths of 20 to 30 cm, seeded, and then covered with jute netting to control erosion during spring freshet. A native seed mix containing 38% tufted hairgrass (Deschampsia ceaspitosa), 25% bluejoint (Calamagrostis canadensis), 25% Arctared fescue (Festuca rubra), and 12% polargrass (Arctagrostis latifolia) was broadcast at 12 kg/ha followed by 24 kg/ha annual rye (Secale cereal), applied as a cover crop (Martens 2013).

In 2013, 90 locally harvested willow (Salix planifolia) cuttings and 36 bog cranberry (Vaccinium vitis idaea) seedlings were planted in topsoil plots and in the rock crush along the channel slopes. In 2014, an additional 383 native wet-tundra seedlings were added. Percent ground cover was much higher on topsoil than on the adjacent rock crush, and survival and size of planted seedlings was generally greater in the topsoil. Survival rates of plants originally established as seedlings appear to have stabilized, and many bore fruit in 2016, the majority of these also being in topsoil. Several colonizing native plants were also noted in the topsoil and a few have moved onto the rock crush (Photos 6.3-4 and 6.3-5).

Source: Dominion 2018e, Appendix I.

Photo 6.3-4 A Very Healthy 60 cm Tall Nodding Cotton Grass Plant in Topsoil at Pigeon Stream Diversion, August 2016



Source: Dominion 2018e, Appendix I.

Photo 6.3-5 Tussock Cotton Grass in Topsoil (left) and Rock Crush (right) at Pigeon Stream Diversion, 2016

6.3.7. Airstrip Vegetation

The side slopes of the Ekati airstrip were revegetated in 1997 with heavy applications of grass seed and fertilizer. The area consists primarily of esker sand and gravel and was recontoured, seeded, and fertilized. A seed mix containing cultivars of four native grasses (creeping red fescue [Festuca rubra], polargrass, alpine bluegrass [Poa alpina], and tundra bluegrass [Poa glauca]) was broadcast at 30 kg/ha and 440 kg/ha 8-32-16 (NPK) fertilizer was applied (Kidd and Max 2001).

For the first few years following reclamation, vegetation on the seeded areas was dominated by the seeded grasses, but they have since declined and been replaced by native tundra shrubs that have colonized naturally. For the past 10 years, total cover by vegetation, including litter, has remained stable at approximately 48%. These results demonstrate that the revegetation work that was done was successful in fostering the return of native species to the area, through natural colonization and species succession. Photos showing the revegetation of the Ekati mine airstrip are provided in Photos 6.3-6 and 6.3-7.



Source: Dominion 2018e, Appendix G.

Photo 6.3-6 View along Transect 9 at the North End of the Ekati Mine Airstrip, July 2017


Photo 6.3-7 View along Transect 5 at the East Side of the Ekati Mine Airstrip, July 2017



6.3.8. South Airstrip Esker Vegetation

Reclamation of the south esker began in 1999 after it was no longer required as a source of aggregate material for road and pad construction. The esker was recontoured to create a number of shallow depressions, and large rocks and boulders were scattered across the surface to emulate surface roughness. Then, in 2002, the 7.4 ha area was split into several treatment blocks which were either seeded with native forbs, seeded with native grass cultivars, or left to revegetate naturally (Figure 6.3-2). The forb seed included two legumes (licorice root [Hedysarum mackenzii] and reflexed locoweed [Oxytropis deflexa]) and fireweed (Epilobium angustifolium). Only limited quantities of forb seed were available, and the seed was applied at a very low rate. The native grass seed mix, consisting of 40% alpine bluegrass (Poa alpina), 40% tufted hairgrass (Deschampsia caespitosa), and 20% spike trisetum (Trisetum spicatum), was applied at 20 kg/ha. After seeding, the entire area, including the blocks left for natural colonization, was fertilized with 16-16-16 (NPK) fertilizer at 50 kg/ha (Kidd and Max 2002).

Long-term periodic monitoring indicates that the most successful revegetation technique employed on this site was fertilizing and seeding with native grasses, although the use of aggressive cultivars (e.g., Arctared fescue) should be limited or avoided. In 2017, total ground cover and species diversity were notably higher in the grass-seeded treatments. Only a very limited quantity of forb seed was available for planting in the forb-seeded areas and this likely contributed to the relatively poor reclamation success in those areas. Natural colonization by native plant species is occurring in all treatments, most notably in the grass-seeded blocks and to a lesser extent the unseeded controls. In 2017, ground cover by mosses is fairly consistent across the entire area, and mosses provide the greatest ground cover in all treatments (Photos 6.3-8 and 6.3-9). Approximately 19 years post-reclamation, lichens have begun to colonize and now contribute a small amount of cover in all treatments.


Figure 6.3-2 South Airport Esker Treatment Areas




Photo 6.3-8 View along Transect 2 in the Grass-Seeded Treatment in 2011


Photo 6.3-9 View along Transect 2 in the Grass-Seeded Treatment in 2017



6.3.9. Fox Portal Vegetation

Revegetation research began at Fox Portal in 1995. Several plant cultivation treatments were applied to three topdressing materials: organic soil, esker sand, and lake sediment. After 21 growing seasons, only the organic soil has appreciable cover by vascular plants, most of which is provided by shrubs (Photo 6.3-10). The other topdressings are not devoid of life, however, and do support trace amounts of vascular plants and some mosses.

The gravel pad on the east side of the site was also seeded in 1995 with a mix containing four native grass cultivars. Two of those grasses made up virtually all of the vascular plant cover recorded in 2016. Competition from the seeded grasses may be slowing natural colonization.

Source: Dominion 2016d, Appendix I.

Note: Clockwise from top left: esker sand, lake sediment, gravel pad, organic soil.

Photo 6.3-10 Typical Views of Topdressings at Fox Portal, July 2016

6.4. Lessons Learned

The key lessons learned in the completed progressive reclamation activities that will inform future closure planning at the Ekati mine are summarized in Table 6.4-1.



Table 6.4-1 Summary of Lessons Learned from Progressive Reclamation Activities

Reclamation Activity Key Lessons Learned

Old Camp • Taking a phased approach to scheduling and completing the activities over multiple construction seasons is more successful than implementing all project components over the course of one construction season.

• Adaptive monitoring requirements need to be outlined in future reclamation plans. • An appropriate contingency value needs to be allocated to the amount of hydrocarbon

soil identified in Phase 1 or 2 environmental site investigations.

PDC slope stabilization

• Agreement and schedule on the relinquishment and return of financial security need to be in place prior to implementation of progressive reclamation activities.

• Closure planning needs be considered as a part of the overall design. The canyon cut at the PDC could have been completed in benches, eliminating the need to stabilize for closure at a later date.

Panda/Koala Underground

• Staged closure of underground workings when they are no longer required is a successful approach that can be applied to progressive reclamation for future Ekati underground projects.

Exploration camps • Use of non-permanent structures for exploration camps facilitates efficient decommissioning for closure and reclamation.

LLCF stabilization • Natural vegetation growth can be an important progressive reclamation mechanism.

PDC, airstrip, south airstrip, and Fox Portal vegetation

• Topsoil provided better ground cover, survival, and size of vegetation than rock crush. • Organic soil topdressing provided greater cover by vascular plants than esker sand or

lake sediment. • Fertilizing and seeding with native grasses can be successful. • Natural colonization of mosses and lichens can occur.

PDC = Panda Diversion Channel; LLCF = Long Lake Containment Facility.



Temporary Closure

Temporary closure occurs when a mining operation ceases with the intent of later resuming activities. Temporary closure could be due to an unplanned closure or could be a planned closure of certain facilities in a complex mining project (MVLWB 2013). These temporary closures could be short term (last for weeks) or long term (last for years).

The Ekati mine consists of a number of mining areas such that temporary closure could apply to all or only some of those areas. An example of closure applying to some facilities only was the successful temporary closure of Misery Pit and WRSA from 2005 to 2012. During this period, all environmental management and monitoring continued.

7.1. Temporary Closure

In terms of the obligations and environmental responsibilities of Dominion, a temporary closure would not mark a significant departure from operations. A period of temporary closure does not trigger any change in the obligations to maintain a closure security for the site that apply during operations.

The goal of temporary closure activities is to ensure the ongoing protection of humans, wildlife, and the environment, including necessary environmental monitoring during the cessation of mining activities until mining operations can resume.

A number of factors, both internal and external, may influence a decision to temporarily shut down mining operations. These include market conditions, economics of ore recovery, ore reserves, regulatory requirements, and ongoing exploration programs. The strategies to be implemented are dependent on the duration of the shutdown.

A temporary closure is a halt of mining and processing operations for economic, operational, or regulatory reasons. Full operation will resume when the cause of the temporary closure has been remedied. By its nature, a temporary closure assumes that reopening of full-scale mining and processing operations will occur in the future; therefore, no final closure of major mine components will be completed during this period. During a period of temporary closure, all environmental monitoring and administrative duties continue as part of licensing and permitting agreements, which continue to be in force. The specifics of the environmental monitoring may require adaptation to the conditions during temporary closure. If required, a new version of the AEMP design plan would be submitted for approval.

7.2. Temporary Closure Activities

With respect to measures conducted under a temporary closure event, activities would be focused on maintaining the stability and integrity of existing facilities and structures. Because the closure is assumed to be temporary in nature, no final closure of the major mine area components would be completed. If progressive reclamation of a mine area component(s) was in progress during a temporary closure, then these activities may continue.

The temporary closure measures outlined below would be dependent on the duration of the temporary closure as well as on the stage of mining development. However, it is expected that the following activities would continue during a period of temporary closure:

• Continue with all activities required for compliance with all applicable federal and territorial laws and regulations.

• Maintain security to restrict access to the site and buildings to authorized personnel only.

• Temporarily guard or block mine openings to prevent unauthorized access.



• Continue the inventory program in place, including inventory of chemicals, reagents, petroleum products, and any other hazardous materials; these products would either be removed or continue to be secured.

• Secure and continue to monitor waste management locations and landfills.

• Securely store on-site mobile equipment.

• Continue ongoing monitoring and maintenance programs to uphold the stability and performance of all Ekati mine components.

• Continue maintenance and inspections of WRSAs, ore stockpiles, dams, dikes, and diversions to maintain physical stability.

• Continue water management and discharge of water that meets Water Licence criteria.

• Maintain water diversions and pipelines to ensure performance until final closure measures are implemented.

• Temporarily block access haul roads to open pits where appropriate.

Adequate maintenance staff will continue to be on site to ensure critical equipment, such as pumps and generators, is maintained in operating condition. Furthermore, adequate management, engineering, technical, and environmental staff and/or consultants will continue to support the operation and ensure all environmental compliance conditions are met.

7.3. Temporary Closure Monitoring, Maintenance, and Reporting

The required monitoring and reporting during the temporary closure would be based on the monitoring procedures and reporting carried out during operations and in compliance with all applicable federal and territorial laws, authorizations, and regulations. The operational monitoring and reporting may require some degree of adaptation to conditions during a temporary closure. If required, a new version of the AEMP design plan would be submitted for approval.

The monitoring procedures and reporting requirements during operations are defined in the Water Licence, Land Use Permits, Fisheries Act Authorizations, and the Environmental Agreement, as well as in the management plans which they require (such as the AEMP and WROMP). However, it is anticipated that due to the reduction in operational activities during temporary closure, the scope of some monitoring programs would be reduced; if this were to be the case, Dominion would develop or revise monitoring plans as needed through engagement with the appropriate regulatory agency and following the appropriate approval processes where applicable.

In the case of a temporary closure, the number of personnel on site would likely be reduced relative to operations. Staff present on site during temporary closure would be sufficient in number and expertise to successfully carry out care and maintenance and monitoring duties and to respond to unplanned occurrences. Consultants would also be used to perform specific care and maintenance and monitoring duties as appropriate.

Sufficient equipment and supplies/reagents would be left on site or otherwise supplied for any maintenance or environmental protection activities that may need to take place.

7.4. Temporary Closure Contingency Program

In the event of temporary closure, staff would be maintained to carry out or supervise monitoring and maintenance activities. In the event of unplanned occurrences, staff would either respond directly to the event or coordinate an appropriate response through the use of contractors, consultants, or short-term hires, depending on the nature of the unforeseen events or conditions.



As part of the temporary closure contingency plan, applicable operational plans, such as the Ekati Spill Contingency Plan (DDEC 2017i), would remain in effect and may be revised in accordance with the appropriate approval processes where applicable.

7.5. Temporary Closure Schedule

There are currently no plans for temporary closure of the Ekati mine, nor is such a closure anticipated in response to foreseeable events. If a temporary closure does occur at some point in the future, it would be in response to an unexpected event or events, and would not correspond to a schedule that can be defined at this time.

In the case of an event, or events, that were to necessitate temporary closure, a specific schedule would be developed as a function of the cause of the temporary closure, its anticipated duration, and the moment in the mine life in which it occurred.

The specific activities needed for each component of the mine in a temporary closure will depend on a number of factors, including the anticipated duration of the temporary closure, the cause, the stage of mine life, and the season. A general overview of the principal activities that may be required for each project component is provided in Table 7.5-1.

Table 7.5-1 Temporary Closure Activities by Project Component

Project Component Potential Temporary Closure Activities

Open pit mine workings • possible temporary access controls (berms, signage, temporary fencing, or gates)

Underground mine workings • possible temporary access controls (berms, signage, temporary fencing, or gates)

Waste rock storage areas • continued routine geotechnical monitoring and inspection

Processed kimberlite containment areas • possible temporary access controls (berms, signage, temporary fencing, or gates) • continued routine geotechnical monitoring and inspection

Dams, dikes, and channels • all systems continue to be inspected and maintained

Buildings and infrastructure • possible temporary access controls (berms, signage, temporary fencing, or gates) • regular inspection • non-essential buildings locked • non-essential power lines discharged and locked open • all equipment maintained in a no-load condition • some equipment may be drained and stored, depending on the duration of the temporary

closure • all fuel storage, chemical reagents, explosive materials, and solvents inventoried

Mobile fleet • non-emergency and non-essential vehicles stored in a secure area or areas • fuel levels monitored • vehicles winterized if necessary



Integrated Schedule of Activities

The integrated schedule of activities presently planned for the mine operations and closure plan for the Ekati mine is presented in Figure 8.0-1. Additional detail on the open pit and underground flooding schedule used for the development of Version 3.0 of the ICRP is presented in Figure 8.0-2. The schedule as presented is indicative, based on the anticipated duration of the various closure and reclamation activities documented in the ICRP, and reflects a logical sequence of activities. The staging of activities shown in the schedule is based on the LOM Plan that was current at the time ICRP Version 3.0 was prepared, and in particular the anticipated date for the end of productive life at each ore body that makes up the Ekati mine. The closure of Jay Pit, which is currently the last pit planned to be developed at the Ekati mine, in this scenario would take place in 2035. The intent of the schedule is to show a rational sequencing and timeframe for reclamation and closure activities that is appropriate to the current LOM Plan. The schedule presented herein should not be interpreted as providing firm dates of execution. The schedule does not include reclamation activities that are currently in the options analysis stage, such as the construction of littoral zones in the pits.

The actual schedule dates for the implementing and completing the planned works are subject to a variety of factors that could change mine plans, such as changes in market conditions, exploration results, the results of reclamation research, and technological or regulatory changes. For example, underground mining is currently under consideration for the Fox kimberlite. If this option is advanced and approved, it would result in a fundamental change to the LOM with a resulting effect on the timing of the closure activities for a number of mine components.

Selected components of infrastructure will remain on site until near the completion of closure and reclamation works. These will include roads, pit flooding camp, and power installations, as well as the airstrip. These components will be closed and reclaimed in accordance with the applicable plan at the end of closure and reclamation of the site.

Roads will generally not be reclaimed until late in the closure period when they are no longer required for reclamation monitoring. Consideration will be given to partial reclamation of some wider roads, such as haulage roads, provided this can be done cost effectively and provide continued safe access for reclamation monitoring; this would be determined for the Final Closure and Reclamation Plan.

Future updates of the ICRP will include updated closure schedules, reflecting the evolution of the LOM Plan. It will be possible to prepare a more detailed schedule after final designs and decommissioning plans have been completed, as part of the Final Closure and Reclamation Plan.

Panda OP

Panda UG

Koala North OP

Koala North Test UG

Koala North UG

Koala OP

Koala UG

Beartooth OP

Fox OP

Misery OP

Misery OP Pushback

Misery UG

Lynx OP

Pigeon OP

Sable OP

Jay OP

2046 2047 2048 2049 20502040 2041 2042 2043 2044 20452034 2035 2036 2037 2038 20392028 2029 2030 2031 2032 20332022 2023 2024 2025 2026 20272016 2017 2018 2019 2020 20212010 2011 2012 2013 2014 20152004 2005 2006 2007 2008 20091997 1998 1999 2000 2001 2002 2003

2045 2046 2047 2048 2049 20502039 2040 2041 2042 2043 20442033 2034 2035 2036 2037 20382027 2028 2029 2030 20312003 2004 2005 2006 2007 20081997 1998 1999 2000 2001 2002 20322021 2022 2023 2024 2025 20262015 2016 2017 2018 2019 20202009 2010 2011 2012 2013 2014

Infrastructure (roads, dams, etc...)

Mine Development (waste mining)

Mine Production (kimberlite and waste mining)

Process Kimberlite Deposition

Mine Water Management

Passive Backflooding

Active BackFlooding

August 2018EKATI MINE ICRP


Figure 8.0-1 Ekati MIne - Integrated Schedule of Activities

Figure 8.0-2 Open Pit (OP) and Underground (UG) Flooding Schedule





8.1. Panda/Koala/Beartooth Development

Beartooth Pit is currently being used for PK deposition and minewater management. PK deposition and flooding of Beartooth Pit are planned to be completed prior to the end of mine operations. Bearclaw Dam will be breached to provide streamflow into Beartooth Pit Lake and reconnection of Beartooth Pit Lake outflow to Upper Panda Lake. This will take place at an appropriate time to be approved by the WLWB.

Decommissioning activities are complete for Panda and Koala North underground mines, with completion of Koala Underground decommissioning planned in the latter part of 2018. Once these activities are complete, PK deposition is planned for Panda/Koala/Koala North open pits and underground workings. PK deposition in the Panda/Koala/Koala North pits will continue through Jay Pit operations. Active pumping to place a freshwater cap on these pits will take place after cessation of mine operations followed, at an appropriate time to be approved by the WLWB, by reconnection to the local hydrological system.

Stabilization of the CKRSA with a rock cover will be completed following cessation of processing operations, as shown in Figure 8.0-1. Reclamation of completed portions the CKRSA may be a potential candidate for earlier (i.e., progressive) reclamation (particularly if vegetation is a feasible option) provided there are no considerations of further expansion; this would be determined at a time closer to final closure.

Mine installations in the central mine area will remain operative until the end of the current LOM Plan. Completion of the demolition and decommissioning works is expected to be spread out over several years, with some installations (such as the landfill and landfarm, for example) retained until later in the closure period as needed to support closure activities and monitoring. The sequencing of the decommissioning activities will be developed as part of final closure design.

8.2. Fox Development

Passive flooding of the Fox Pit is currently ongoing, with active flooding planned for later in the mine life. Initiation of active flooding may vary depending on the results of ongoing exploration and economic evaluations of potential mining of the deeper portions of the Fox kimberlite underlying the open pit.

The Fox WRSA stabilization of the kimberlite “low-grade” stockpile with rock is planned to be completed following cessation of processing operations, as shown in Figure 8.0-1. Provided there are no considerations of processing this material, reclamation of some or all of the area to be stabilized may be a potential candidate for earlier (i.e., progressive) reclamation, particularly if vegetation is deemed as a feasible option for stabilization.

Relatively little infrastructure is present at the Fox area. As such, it is expected that infrastructure decommissioning can be completed in one year.

8.3. Misery and Lynx Development

Lynx Pit will be closed through back-flooding with natural lake water from Lac du Sauvage, water from dewatering of the Jay diked area, and then subsequent passive flooding. The closure of Lynx will be linked with the timing for the end of operations at MUG, as Lynx Pit will be used for minewater management during the MUG operations. The completion of the back-flooding of Misery Pit and underground workings will be linked with operations at Jay, as a portion of the minewater from Misery Pit will be pumped to the bottom of Jay Pit after mining activities are completed there to allow for the placement of the freshwater cap at Misery Pit. Following this transfer, the upper layer of Misery Pit will be actively back-flooded with freshwater from Lac du Sauvage. Closure activities for the Misery/Lynx WRSAs, with placement of the final lift of non-PAG material and the associated final grading, would be carried out in parallel with back-flooding activities for Misery Pit. It has been assumed that removal of associated infrastructure will take place at some time after the completion of back-flooding. Breaching of site dams (King Pond, Saddle, Waste Rock Pond) and dikes (Desperation Pond) will be completed at an appropriate time to be approved by the WLWB.



8.4. Pigeon Development

Passive flooding of Pigeon Pit will occur for several years following the completion of mining, followed by active flooding from Upper Exeter Lake to be completed as progressive reclamation. Removal of infrastructure (including relocation of the outlet of the flooding pipeline to Beartooth Pit) would be completed during and following the completion of flooding. Reclamation of the Pigeon WRSA (based on selection options analysis) would take place prior to Ekati mine closure. Construction of the Pigeon Pit Lake outflow channel to Pigeon Stream will be completed at an appropriate time to be approved by the WLWB.

8.5. Sable Development

Passive flooding of Sable Pit will occur for several years following the completion of mining, followed by active flooding from Ursula Lake, as shown in Figure 8.0-1 and Figure 8.0-2. Limited works will be needed for the closure and reclamation of the Sable WRSA, and there is flexibility in what year these works are completed. For initial planning purposes, it has been assumed the works will be carried at the end of Ekati mine operations. Breaching of the Two-Rock Dam and (internal) dike and construction of the Sable Pit Lake outflow channel to Two-Rock Sedimentation Pond will be completed at an appropriate time to be approved by the WLWB.

8.6. Jay Development

The schedule for the closure of Jay Pit includes an allowance for the removal of mine equipment from the pit and diked area, and initiation of active back-flooding using minewater pumped from Misery Pit. Once back-flooding is completed (including the transfer of minewater from Misery Pit and freshwater pumped from Lac du Sauvage to fill the pit and diked area), and monitoring confirms that water quality is suitable for mixing with Lac du Sauvage, the breaches in the Jay Dike will be constructed, reconnecting the diked area with Lac du Sauvage. The timing for dike breaching and reclamation of the Sub-Basin B Diversion Channel will be approved by the WLWB prior to initiation.

8.7. Long Lake Containment Facility

Reclamation research work at the LLCF is ongoing and will continue such that reclamation prescriptions for Cells A, B, and C of the LLCF are developed. Progressive reclamation of the upper areas of the LLCF (Cells A, B, and C) will proceed while mining at Jay Pit is underway. Breaching of Dyke D and E will occur after the LLCF is not needed for minewater management.

8.8. Site Wide

A number of final closure activities will be carried out that affect the entire site. These include final decommissioning activities for installations that are not associated with individual components, such as power lines, roads, and the infrastructure that was left in place for support of closure activities. Minor earthworks are also anticipated for improvements to site-wide drainage. While the activities for this are limited in scope, they are likely to be spread over several years at the end of the closure period. Finally, an allowance for completion of hydrocarbon remediation is included at the end of the closure period to account for remediation activities that may need to be carried out in association with the final decommissioning activities.



8.9. Monitoring and Maintenance and Relinquishment Reporting

The required post-closure monitoring and maintenance activities vary with the different areas of the mine. Post-closure monitoring will be undertaken on a component-by-component basis to enable timely evaluation, security reduction, and relinquishment where appropriate. In particular, post-closure monitoring at each pit will commence when the back-flooding activities have been completed. A period of 10 years of monitoring after the completion of pit flooding has been assumed for the calculation of the financial security, but the duration could be more or less depending on results. Monitoring will continue until closure criteria are met. Further details on monitoring and maintenance durations for each component of closure are provided in Chapter 5 of this document.

Reporting on the progress of progressive reclamation and reclamation research will also continue, with annual closure and reclamation plan progress reports. As individual components of the closure and reclamation work are completed, reclamation completion reports will also be submitted.



Post-closure Site Assessment

The following provides a description of how the residual environmental effects of the reclaimed Ekati mine site will be evaluated and the associated monitoring and reporting mechanisms.

9.1. Summary of Predicted Post-closure Residual Environmental Effects

The predicted post-closure residual environmental effects are described for each mine component type in Chapter 5 and summarized in Table 9.1-1.

Table 9.1-1 Summary of Post-closure Residual Environmental Effects by Mine Component

Component Land Use Effects (Wildlife and Human Use)


Open Pits (Section 5.3) • Landscape is altered through the removal of Sable, Panda, Pigeon, Beartooth, Koala, Fox, Misery, and Lynx lakes and conversion to pit lakes at closure.

• Wildlife and human movement may be affected by landscape alteration and remaining closure structures (noting that residual pit walls are anticipated to provide good nesting habitat for raptors).

• Nutrient sinks are present in pit lakes due to increased depths of pit lakes, and as a result, their ecological productivity is lower than adjacent natural lakes.

Underground Mines (Section 5.4) • none • none

WRSAs (Section 5.5) • WRSAs will remain over 1,414.3 ha of the site. WRSAs will range in height from 50 to 70 m above the surrounding ground surface. A permanent visual effect on the landscape will remain from the presence of WRSAs. WRSAs were designed to balance the effects of the height of the WRSA versus the footprint.

• The permanent visual effect may affect use of the land for traditional activities, such as hunting and fishing.

• The WRSAs will represent a permanent modification of the terrestrial habitat. Land use by wildlife within the footprint of the WRSAs and the growth and type of vegetation will be different than in pre-mining conditions. However, the WRSAs will be designed and closed to be safe for wildlife at closure and will consider site-wide wildlife movement (especially caribou) through the reclaimed mine site, as well as habitat use of reclaimed areas.

• Seepage from the WRSAs represents a change in hydrology and water quality. WRSAs are built and will be closed to mitigate the risk of poor quality seepage and are closely monitored to determine potential for adverse effects.



Component Land Use Effects (Wildlife and Human Use)


PKCAs (Section 5.6) • Landscape is altered through the revegetation and reconfiguration of the LLCF.

• The revegetated LLCF will be dry, flat, and stable, posing low risk to wildlife movement through the area. Monitoring to date has shown wildlife use within the research plots; however, overall, the area is anticipated to have lower forage potential than the surrounding heath tundra.

• Metals in vegetation cover as a result of uptake from the LLCF are expected to have minimal health concerns for consumption by wildlife and humans consuming wildlife using the LLCF.

• The LLCF Discharge water quality is predicted to have negligible effects on the Receiving Environment through closure. Water will be managed prior to breach of the Outlet Dam and monitoring results will be used to evaluate the need for the implementation of additional water quality mitigation efforts at the reclaimed areas.

Water Management Infrastructure (Section 5.7)

• Remnants of dams and dikes will remain in some areas, which will lead to changes in the appearance of the landscape.

• Remnants of dams and dikes will remain in some areas, which will lead to changes in the habitat types in these areas, and the wildlife travel corridors as compared to pre-disturbance conditions. However, any habitat that is reclaimed at closure will be safe for wildlife.

• Drainage and water quality will be permanently changed by the redesign of the drainage system during operations and the connection of pit lakes and sedimentation/minewater management ponds to the overall closure drainage system. Care will be taken to monitor water quality to determine potential effects of dike breaching or reconnection activities and control the timing of the reconnection to the Receiving Environment.

• The dams, dikes, channels, and ponds associated with the Ekati mine are a permanent change to the aquatic landscape. Some lakes, channels, and ponds that were present at pre-disturbance have been permanently removed (compensation/offsetting developed as requirements under the Fisheries Act to offset losses to fish habitat) and new watercourses and waterbodies have been or will be added. Use by fish within the reclaimed hydrological systems may be different than in pre-mining conditions, but where appropriate, reclamation of ponds and connecting channels will provide conditions that are safe for fish.

Buildings and Infrastructure (Section 5.8)

• There will be permanent visual effects with some roads and pads remaining on the landscape at closure; this may affect the use of the land for traditional activities, such as hunting and fishing.

• Some roads and the airstrip at the Ekati mine will represent a permanent modification of terrestrial habitat. These corridors will change vegetation types and topography on the closure landscape, and are expected to provide new corridors that wildlife can safely gain access and egress, but may impede existing travel corridors.

• none

WRSA = waste rock storage area; PKCA = processed kimberlite containment area; LLCF = Long Lake Containment Facility.



9.2. Previous Assessment of Post-closure Residual Environmental Effects

The residual environmental effects as summarized in Table 9.1-1 are consistent with the findings from the previous assessments. The post-closure residual environmental effects for the Ekati mine have been assessed through various environmental assessments since the original NWT Diamonds Project for the Ekati mine in 1995 (Table 9.2-1). These assessments found that the predicted residual effects after closure and reclamation were not significant, and all of the assessments resulted in project approvals.

Version 3.0 of the ICRP also considered the residual effects identified in Version 2.4 of the ICRP (BHP Billiton 2011a) and subsequent annual reports.

Table 9.2-1 Summary of Environmental Assessments Completed for Ekati Mine Components

Project Location/Details Reference

Main Ekati mine (NWT Diamonds Project)

Environmental Impact Statement for open-pit and underground development of Panda, Koala, Koala North, Fox, Leslie (Leslie kimberlite pipe has not been developed), and Misery

BHP and Dia Met 1995

Sable, Pigeon, and Beartooth Expansion

Developer’s Assessment Report for expansion for three new kimberlite pipes not included in the original application: Sable, Pigeon, and Beartooth pipes

BHP Diamonds Inc. 2000

Lynx Project preliminary screening assessment for the development of the Lynx kimberlite pipe DDEC 2013f

Misery power line preliminary screening assessment for a power line from the Ekati mine main site to Misery

DDEC 2014c,d

Jay Project Developer’s Assessment Report for the development of the Jay kimberlite pipe in Lac du Sauvage

DDEC 2014a

Misery Underground Project preliminary screening assessment for underground mining of the Misery kimberlite pipe DDEC 2017n

As the closure measures described in ICRP Version 3.0 are consistent with those considered for post-closure in the previous EAs, the residual environmental effects summarized in Table 9.1-1 are considered acceptable and not expected to cause significant adverse effects.

From the initiation of the Ekati mine and during operations, residual effects to fish and fish habitat were also subject to the habitat protection provisions of the Fisheries Act. Fish habitat losses that required a Fisheries Act Authorization from DFO under Section 35(2) of the Fisheries Act required compensation (or offsetting) to offset these losses. The Ekati mine currently operates under five Fisheries Act Authorizations (SCA96021, SC00028, SC01111, SC99037, and 15-HCAA-0026) and one is currently in progress for Jay Project. Monitoring is required to determine if the objectives of the compensation or offsetting have been met. The monitoring will be completed during mine operations, and in some cases, into the closure or post-closure period depending on the conditions of the Authorization.

Closure and reclamation planning is a requirement of the Environmental Agreement that will be in force until the full and final reclamation of the Ekati mine is complete. The three-year EIR reports on environmental impacts as a requirement of the Environmental Agreement.

9.3. Ongoing Evaluations During Ekati Mine Operations

There are a number of processes currently in place at the Ekati mine, and regulatory frameworks that must be followed, that will ensure that any changes to the planned closure measures that may affect post-closure residual environmental effects and/or post-closure risks are appropriately evaluated (Table 9.3-1). These processes will continue to be in effect throughout mine operations.



Table 9.3-1 Summary of Evaluation Processes / Regulatory Frameworks during Ekati Mine Operations

Process Description

Environmental management plans

• The Ekati mine has environmental management plans in place for the existing mine operations. Many of the plans are requirements of the Ekati mine Water Licence and, as such, are also subject to the public review and approval process conducted by the WLWB.

• Operational environmental management plans (such as the WROMP and WPKMP) describe how operating procedures integrate with planned closure measures, such that potential implications for post-closure residual risks are identified and evaluated.

• The operational management plans provide adaptive management response frameworks to keep environmental effects within expected/accepted boundaries.

• Each of the plans undergoes, and will continue to undergo, periodic review and amendment according to current circumstances and in accordance with the principles of adaptive management.

• Changes to operational environmental management plans are reviewed by the WLWB and cannot be implemented until approved.

Environmental monitoring programs

• The Ekati mine has existing monitoring programs that provide for the ongoing collection of information related to environmental conditions at the Ekati mine (e.g., AQEMMP, AEMP, SNP, WEMP, WROMP).

• Many of the monitoring plans are requirements of the Ekati mine Water Licence and, as such, are also subject to the public review and approval process conducted by the WLWB. Other environmental monitoring plans (i.e., the AQEMMP and the WEMP) also have a review process that allows input from government agencies and Indigenous communities.

• The operational monitoring plans provide adaptive management response frameworks to keep environmental effects within expected/accepted boundaries.

• Each of the plans undergoes, and will continue to undergo, periodic review and amendment according to current circumstances and in accordance with the principles of adaptive management.

• Changes to environmental monitoring plans that are required under the Water Licence are reviewed by the WLWB and cannot be implemented until approved.

Environmental assessment of new developments

• New developments go through preliminary screening through the WLWB or EA through the MVEIRB. • This assessment process includes the review of any new project-specific closure measures and

evaluation of potential changes or additions to the existing ICRP closure measures. • In this way, the assessment of new developments evaluates predicted post-closure residual

environmental effects and approval of a new development would only occur if these residual effects are deemed acceptable and not cause significant adverse effects on the environment.

Annual progress reporting • A reclamation progress report is provided to the WLWB annually to document reclamation activities conducted during the year and to propose, with rationale, any desired updates to planned closure measures.

• Updates to planned closure measures are reviewed by the WLWB and cannot be instituted until approved. In this way, potential implications for post-closure residual environmental effects and/or risks are identified and evaluated.

EIR • An EIR report is circulated every three years as described in the Environmental Agreement. • The three-year EIR compares the results of environmental monitoring activities conducted by Dominion

at the Ekati mine with the predictions of the 1995 EIS. • This report summarizes and reports on current operational environmental effects as compared to

expectations, which enables an evaluation of whether operational effects and mitigations may present implications for post-closure residual environmental effects.

• This report is distributed and reviewed through a process led by the GNWT.

Indigenous community engagement and TK

• Community engagement, and specifically the TKEG, ensure that direct community feedback and TK are considered in closure planning and in the mitigation of residual environmental effects where possible.

ICRP updates • Dominion has proposed that the ICRP be updated every five years, beginning with approval of Version 3.0.

• This approach will ensure that post-closure residual environmental effects are reconsidered on a periodic basis prior to final closure.

Final closure plans • Individual final closure plans for specific mine components for which final reclamation is planned during Ekati mine operations (such as Old Camp/Phase 1 PKCA) will be provided for WLWB review and approval.

• These component-specific plans consider the predicted residual environmental effects and describe any implications for post-closure residual risks.



Process Description

Research and monitoring • Reclamation research is based on uncertainties that may exist in the type and extent of residual environmental effects remaining after mine closure. Key uncertainties are addressed through research and engineering studies.

• Monitoring of progressive reclamation activities will also inform the future evaluation of post-closure residual environmental effects and allow adaptive management approaches to be implemented.

WLWB = Wek'èezhı̀ı Land and Water Board; WROMP = Waste Rock and Ore Storage Management Plan; WPKMP = Wastewater and Processed Kimberlite Management Plan; AQEMMP = Air Quality and Emissions Monitoring and Management Plan; AEMP = Aquatic Effects Monitoring Program; SNP = Surveillance Network Program; WEMP = Wildlife Effects Monitoring Program; EA = Environmental Assessment; MVEIRB = Mackenzie Valley Environmental Impact Review Board; ICRP = Interim Closure and Reclamation Plan; EIR = Environmental Impact Report; EIS = Environmental Impact Statement; GNWT = Government of the Northwest Territories; PKCA = Processed Kimberlite Containment Area; TK = Traditional Knowledge; TKEG = Traditional Knowledge Elders Group.

9.4. Future Evaluations for Closure/Post-closure

The Ekati mine will continue to evaluate the anticipated post-closure conditions of the mine site during operations and measured conditions into closure and post-closure.

The Environmental Agreement will remain in place through the reclamation period, as will other permitting and licence requirements (the Water Licence will be renewed and revised through the reclamation period). As required under the Environmental Agreement, the Ekati mine is required to report on the environment to regulators, Indigenous communities and organizations, and IEMA at a regular frequency. The three-year EIR will continue through operations, reclamation, and post-closure monitoring phases.

As per Part K, Condition 5 of the Ekati mine Water Licence, the Final Closure and Reclamation Plan is required a minimum of two years prior to the end of commercial operations. As described in the MVLWB (2013) Closure Guidelines, the Final Closure and Reclamation Plan will include final statements of closure objectives and closure criteria that will be used to determine whether the selected closure activity meets the closure objective and provide detailed descriptions of the proposed reclamation activities for the Ekati mine. A post-closure risk assessment (Human Health and Environmental Risk Assessment [HHERA]) will be provided with the Final Closure and Reclamation Plan two years prior to planned permanent closure, in support of the final closure designs, objectives, and criteria. A summary of reclamation already completed or in progress will be included, and detailed closure and reclamation lability costs and financial security estimates based on achieving the objectives and criteria. The Final Closure and Reclamation Plan will be approved by the WLWB before permanent closure takes place.

Reclamation completion reports will be completed for individual facilities or components as they are closed and reclaimed at the Ekati mine; this can occur through progressive reclamation (e.g., Old Camp, Phase 1 PKCA, or PDC physical stabilization work), or at mine closure. The purpose of these reports is to demonstrate that closure objectives have been achieved and that residual environmental effects are within the established and accepted boundaries. Each report will provide details of the final reclamation work as per the approved design and Final Closure and Reclamation Plan, inventory of infrastructure removed/remaining, engineered as-built reports, and descriptions of any monitoring still to take place. The reclamation completion report facilitates future assessment, maintenance, and repair work at the site, if needed. There may be an opportunity to revise the financial security with the completion of each reclamation completion report.

The performance assessment report is prepared after the final reclamation completion report has been submitted and after a time period needed to assess the performance of reclamation. Once again, this can be through progressive reclamation of site components or at mine closure. The performance assessment report will provide a detailed comparison of conditions at the site against the final closure objectives and criteria. There may be an opportunity to revise the financial security with the completion of performance assessment report.



The purpose of this evaluation and reporting process is to lead to successful relinquishment. Full relinquishment will occur when Dominion is released from the liability associated with the Ekati mine, resulting in a return of the security. Relinquishment will be determined based on monitoring demonstrating that the closure objectives and closure criteria have been met with the supporting documentation in one or more performance assessment reports.

9.5. Post-closure Environmental Monitoring Programs

The overall residual environmental effects of the closed and reclaimed Ekati mine will be further evaluated through monitoring and reporting programs that will be expected to transition from operations, to closure, to post-closure.

Monitoring and reporting on the potential residual effects to wildlife, terrestrial, and aquatic environments will continue during closure and post-closure. A summary of proposed monitoring programs for each mine component is provided in Chapter 5. Monitoring will be implemented to determine whether the post-closure residual environmental effects are consistent with those determined in the Final Closure and Reclamation Plan (and as currently outlined in Table 9.1-1). Monitoring will be used to determine whether sites are stable or trending towards desired outcomes, and if there are trends requiring the implementation of contingencies (i.e., through an adaptive management framework).

Monitoring is expected to continue until closure objectives and criteria are achieved. The current closure objectives and criteria are outlined for each component in Chapter 5; these will continue to be refined in future versions of the ICRP and in the Final Closure and Reclamation Plan to be submitted two years prior to planned permanent closure. For the purposes of financial security estimates, the monitoring period is estimated to be 10 years after the closure of each facility. However, the durations may be modified (reduced or extended) dependent on reflected trends and results. Monitoring results will indicate when reclamation work has been successful, or if there is a need for further reclamation work.

Post-closure monitoring programs and schedules will be tailored to individual closure criteria; however, many of the monitoring programs will use similar parameters, methods, quality assurance / quality control protocols, and evaluation as the current operational monitoring programs. Most of these monitoring programs undergo modifications based on legal requirements and lessons learned during monitoring. The operational programs will be adapted to the closure programs in the progressive reclamation and final closure phases, with the primary purpose of monitoring the success of reclamation activities in meeting identified closure objectives, using measurable closure criteria. Review and modification of these programs will continue through closure, eventually scaling down and combining as the closure operation declines. The main environmental monitoring programs that will be used to measure the residual environmental effects in post-closure are expected to include the SNP, Seepage Monitoring Program, AEMP, AQEMMP, Vegetation Monitoring Program, and WEMP.



Financial Security

10.1. Introduction

Following the WLWB’s approval of the ICRP (Version 2.4), an updated estimate for the total reclamation security for the Ekati mine was provided in 2013. In response to requests from the WLWB and other parties, the 2013 Security Estimate was prepared using the RECLAIM costing model (DDEC 2013g). After stakeholder review of the proposed security estimate, the WLWB provided a final determination on 17 June 2013. Since 2013, the Ekati mine security has been reviewed annually, with RECLAIM estimates submitted in reclamation progress reports. Updates to the RECLAIM estimate have also been provided as part of various Water Licence permitting applications for new Ekati mine development projects such as Lynx and Jay pits, and the MUG. Provided in Table 10.1-1 is a summary of Ekati mine WLWB security review determinations since 2013.

Table 10.1-1 RECLAIM Wek'èezhı̀ı Land and Water Board Security Determinations

WLWB Security Review Item WLWB Security Determination Date

RECLAIM Increase/(Decrease)

RECLAIM Grand Total Amount

2013 Ekati Security Estimate 17-Jun-13 --- $263,700,464

Lynx Development – 2013 Water Licence Amendment and Land Use Permit Application 30-Apr-14 $2,795,537 $266,496,001

2013 and 2014 Closure and Reclamation Progress Reports 12-Jun-15 $2,155,025 $268,651,026

Ekati Land Use Permit W2015D005 Lynx WRSA Security and Reclamation Plan with additional security updates 25-Sep-15 $1,098,454 $269,749,480

2015 Closure and Reclamation Progress Report 15-Jun-16 ($3,069,432) $266,680,048

Jay Early Works Development - 2016 Land Use Permit Application 19-Jul-16 $1,477,916 $268,157,964

Jay Development - 2016 Water Licence Amendment and Land Use Permit Application 29-May-17 $15,954,028 $284,111,992

2016 Closure and Reclamation Progress Report 26-Jun-17 $1,749,843 $285,861,835

Pigeon WRSA Design Report and WROMP Version 7.0 28-Sep-17 $7,935,639 $293,797,474

Misery Underground Development – Water Licence Amendment and Land Use Permit Application 12-Jul-18 $1,118,781 $294,916,255

Note: Numbers in parentheses and red font are reductions in security amounts.

WLWB = Wek'èezhı̀ı Land and Water Board; WRSA = waste rock storage area; WROMP = Waste Rock and Ore Storage Management Plan.

Dominion has provided an updated RECLAIM estimate that corresponds to ICRP Version 3.0 in Appendix H. It should be noted that that the proposed update is based on a RECLAIM estimate that was recently approved by the WLWB, as outlined in 12 July 2018 WLWB reasons for decision on the MUG project (WLWB 2018). This recently approved version included the security determination for the MUG development.



Table 10.1-2 provides a summary of the proposed RECLAIM updates with a total proposed decrease of $17,521,280 to the RECLAIM estimate. This decrease represents the net impact of increases and decreases in different line items, as summarized in the table. The main changes to the estimate result from alignment of closure objectives and activities for the WRSA, optimizations and updates to the open pit flooding program, updates to the Ekati mine demolition estimate, and costs associated with reclamation of the underground workings. Other updates include adding allowances in the security for maintenance work after the completion of the reclamation activities and increasing the person-days considered in the accommodation allowances. The ongoing process of revisiting and updating the RECLAIM estimate allows current costs and inflationary effects to be progressively incorporated into the estimate. For instance, cost estimates for the pit flooding optimization and building demolition incorporate recent experience and quotes for material supplies, together with the updated material quantities. Additional details for each line item in Table 10.1-2 are provided in the subsections that follow.

Table 10.1-2 Interim Closure and Reclamation Plan Version 3.0 RECLAIM Updates

Ref # RECLAIM Update RECLAIM Grand Total Change Increase/(Decrease)

V. 3.0 #1 Fox waste kimberlite physical stabilization cover ($18,348,713)

V. 3.0 #2 Landfill physical stabilization cover ($287,041)

V. 3.0 #3 Hydrocarbon-impacted materials cover $136,342

V. 3.0 #4 Pit flooding optimization ($4,869,995)

V. 3.0 #5 Infrastructure demolition $5,468,793

V. 3.0 #6 Reclamation maintenance $750,000

V. 3.0 #7 Primary accommodations $913,920

V. 3.0 #8 Scarifying and vegetation $667,520

V. 3.0 #9 Underground reclamation ($1,952,106)

TOTAL: ($17,521,280)

Note: Numbers in parentheses and red font are decreases.

10.2. Fox Waste Kimberlite Physical Stabilization Cover (V. 3.0 Ref #1)

As outlined in Section of 5.5.5.3.3 of the ICRP, the exposed waste kimberlite materials at the CKRSA and Fox WRSA that are potentially erodible (due to their overall grain size) will be physically stabilized by either placing a rock cover or through vegetation if deemed feasible. For costing purposes, it is conservatively assumed that the entire surface areas of these erodible waste kimberlite areas will be physically stabilized with a 1 m rock cover. No allowances have been made for stabilizing some areas using vegetation as the estimate conservatively assumes all areas are covered with rock.

Previously submitted RECLAIM estimates considered a 1 m rock cover over the CKRSA and 5 m rock over the waste kimberlite at the Fox WRSA. This practice was largely in place as a result of the WLWB security determination on the 2013 Ekati Diamond Mine Estimate (see 17 June 2013 Reasons for Decision; WLWB 2013). Given the similar geochemical properties of waste kimberlite at both locations, and work completed as part of the WRAF (as summarized in Section 5.5 of the ICRP), Dominion has considered a unified 1 m rock cover for both areas. This represents an overall decrease of $17,521,280 to the RECLAIM estimate.



10.3. Landfill Physical Stabilization Cover (V. 3.0 Ref #2)

As part of the 12 June 2015 WLWB Reasons for Decision on the 2014 annual progress report, the WLWB indicated that “the Board has approved the requested change in closure objective for the operation and demolition landfills and requires DDEC to place a 2 m cover on both landfills to address stability concerns (Decision #6)” (WLWB 2015). Based on this decision, a 2 m rock cover was used in past estimates to ensure physical stabilization of the inert waste. As outlined in Section 5.5.5.3.5 of this ICRP, the non-reactive nature of waste kimberlite has been further documented. Dominion has therefore updated the composition of the inert material landfill cover to reflect a 2 m cover that consists of a 1 m lift of waste kimberlite for physical isolation followed by a 1 m lift of non-PAG waste rock. This represents an overall decrease of $287,041 to the RECLAIM estimate.

10.4. Hydrocarbon-Impacted Materials Cover (V. 3.0 Ref #3)

As outlined in Section of 5.5.5.3.2 the ICRP, hydrocarbon-impacted soil and rock less than 4 cm will be remediated in situ or disposed of off site at the end of closure activities. Remediated soil may be used for site reclamation work, and all residual remediated soil in the Landfarm will be physically stabilized as required.

The areas of Zone S at the Panda/Koala/Beartooth and Misery WRSAs (hydrocarbon-impacted rock and soil greater than 4 cm) that are not already covered will be covered with non-PAG material at closure. For costing purposes, a 1 m thick rock cover was assumed for all areas. Surface areas in the cost estimate were updated based on the Landfarm as-built area of 5,386 m2 and Zone S areas of 27,000 m2 at the Panda/Koala Beartooth WRSA (Map 5.5-2) and 7,500 m2 at the Misery WRSA (Map 5.5-6). The overall changes represent an increase of $136,342 to the RECLAIM estimate.

10.5. Pit Flooding Optimization (V. 3.0 Ref #4)

The pump flooding schedule and associated required infrastructure (pumps, pipelines, and access roadways) has been updated and optimized as part of the development of ICRP Version 3.0, with a focus on optimizing the time required to pump flood the pits and the infrastructure required. The optimized updated pump flooding schedule and required infrastructure is provided in Appendix F. Also provided in Appendix F as an addendum is updated cost information for the pumps, pipelines, access roads, and pit flooding support staff. Table 10.5-1 presents a summary of the changes to the RECLAIM estimate that resulted from the pit flooding optimization process.

Table 10.5-1 Pit Flooding Optimization RECLAIM Changes

RECLAIM Item Increase/(Decrease)

Accommodations & Airfare ($9,055,015)

Support Staff ($6,807,889)

Pit Flooding Monitoring ($100,000)

Pump Fuel and Electrical Power $6,288,103

Pump and Pipelines $4,686,924

Access Roads $71,764

Contingency + PM + Eng + Health and Safety $46,118

RECLAIM GRAND TOTAL CHANGE ($4,869,995)

Note: numbers in parentheses and red font are decreases.

PM = project management; Eng = engineering.



Overall, the optimization process resulted in a decrease of $4,869,995. The decrease in costs is primarily driven by having a shorter and condensed pit flooding schedule that is completed after closure in conjunction with all other reclamation activities. This contrasts the previous pit flooding schedule, which required a dedicated pit flooding program (with supporting accommodations and airfare after the completion of the primary reclamation activities). Provided below is further discussion of the pit flooding optimization RECLAIM changes:

• Accommodations and airfare—There is an approximately $9.1 million cost reduction in not having to have a dedicated pit flooding program with supporting airfare and accommodations after the main reclamation activities have been completed. It should be noted that savings includes cost for an additional 9,683 person-days (116,190 hours divided by 12-hour work) for support staff that have been allocated to the primary reclamation activity period.

• Support staff—Support staff will be required throughout the active flooding period from 2021 to 2039, for periodic inspection and maintenance of pumps, as well as for the periodic collection of water samples and other monitoring activities. This optimization represents a decrease of approximately $6.8 million. The level of effort required per each pit and detailed information around the cost assumptions is provided in Appendix F.

• Pump fuel and electrical power—There is an increase of approximately $6.3 million as result of the needed pump fuel and power requirements. These costs are a result of updated and increased pump fuel consumption specifications and from larger pumping volumes required for the flooding of Panda/Koala, Fox, and Lynx pits.

• Pump and pipelines—Increase of approximately for $4.7 million from updated costs estimated for the purchasing and installation costs for the pumps and pipes. Refer to the Appendix F addendum for further information on the development of the unit costs for the pump and pipelines.

• Monitoring—The pit flooding plan resulting from the Jay Project had estimated costs of $1.1 million for monitoring during pit flooding (54 total cumulative monitoring years × $20,000 per year per pit monitoring). Based on the updated pit flooding schedule and durations as summarized in Table 5.6 of Appendix F, a new total of 49 cumulative monitoring years is estimated. This updated duration represents a relatively small decrease of $100,000 to the RECLAIM estimate.

• Access roads—Pit flooding access road needs and updated unit costs for the construction of access roads are summarized in Appendix F. Using this updated information results in a relatively small increase of approximately $72,000 to the RECLAIM estimate.

• Contingency and indirect costs—Based on the development and engineering advancement of the pit flooding, a contingency value of 10% was selected for costs associated with pumps and the quantity of fuel required. For all other pit flooding items, a 15% contingency value was maintained. In total, the optimized pit flooding program resulted in a small increase of $46,000 to the RECLAIM estimate for contingencies and indirect items including project management, engineering, health and safety, and bonding/insurance.

10.6. Infrastructure Demolition (V. 3.0 Ref #5)

Golder has reviewed the provisions for decommissioning the site infrastructure and prepared an updated estimate. The update to the infrastructure decommissioning provision was based on the most current description of the site infrastructure, as presented in Section 5.8 of the ICRP Version 3.0. The update incorporated the following sources of information:

• past decommissioning provisions for site infrastructure, with costs corrected to 2018 dollars

• decommissioning provisions that were developed in 2017 for the Jay expansion



• new estimates developed for the infrastructure that is included in ICRP Version 3.0 and was not addressed in the previous documentation

The available information documenting the basis of the estimates was reviewed, and the estimates consolidated to eliminate duplication. The new estimates were developed based on plans, photographs, satellite imagery, and descriptions provided by Dominion. Where more detail was not available, representative assumptions were made. The estimated costs include allowances for an appropriate level of abatement (e.g., sludge removal from fuel storage tanks), demolition, and removal of demolition residuals. All costs were estimated as current (2018) costs based on recent experience and current demolition methods, and no offsets for salvage values were discounted from the estimates. On-site measurements were not carried out in support of the update, and the assumptions in past estimates were not updated. The total estimated decommissioning cost for the infrastructure developed by Golder, and included in the updated RECLAIM estimate, is $13,221,400. This represents an increase of $5,468,793 to the previous RECLAIM grand total estimate. A breakdown of the costs developed by Golder is summarized in Table 10.6-1, including the components of the total that correspond to amounts from the 2017 Jay estimate, the 2012 estimate escalated to 2018 costs, and the current Golder estimate for additional infrastructure. The 2017 Jay amounts for culverts and powerlines were adjusted to eliminate double-counting with updated estimates for these components in the 2018 estimate. It should be noted that included in the Misery development cost is the $705,000 cost for the Jay crusher demolition since it is located within Misery Lease boundary. Additionally, the Misery development costs includes the Misery Camp expansion cost of $981,500 that had been allocated to the Jay development cost in the 2017 Golder estimate.

Table 10.6-1 Golder Estimate Summary of Decommissioning Costs

Facility Area Total Golder 2018 (additional infrastructure)

Golder 2018 (2012 estimate escalated)

Golder 2017 (Jay development)

Increase/(Decrease)

Panda/Koala/Beartooth Pit development $5,498,000 $5,498,000

Panda/Koala Underground development $680,000 $680,000

Fox development $217,000 $80,000 $137,000

Misery development (open pit and underground) $3,043,500 $950,000 $407,000

Pigeon development $85,000 $85,000

Sable development $851,500 $851,500

Lynx development $65,000 $65,000

Jay development $332,700 $895,000 $1,124,200

Culverts (excluding Jay) $402,500 $402,500

Culverts (Jay) $35,000 ($656,200) $691,200

Pipelines $1,112,200 $625,000 $487,200

Bridges $270,000 $270,000

Powerlines (excluding Jay) $534,650 $534,650

Powerlines (Jay) $94,350 ($382,050) $476,400

TOTAL: $13,221,400 $3,720,400 $6,722,000 $2,779,000

Note: numbers in parentheses and red font are decreases



10.7. Reclamation Maintenance (V. 3.0 Ref #6)

It is difficult to develop accurate estimates of maintenance costs without data from one or more years of post-construction monitoring. It is also impractical to define a priori how much of the maintenance effort will go to minor civil earthworks to address issues that could potentially affect any aspect of the site closure (e.g., erosion repairs, reshaping or sealing cracks from minor settlement) and how much to maintenance that is oriented towards specific areas such as revegetation.

A reasonable and representative provision has been estimated based on a level of effort that is commensurate with the size and complexity of the site. An allowance of $150,000 per annum has been estimated to carry out maintenance activities after completion of reclamation activities. This estimate was based on a level of effort equivalent to a single crew undertaking an annual campaign of minor civil earth work. Considering this annual provision for the five-year duration of reclamation activities represents an increase of $750,000 to the RECLAIM estimate, as an allowance for maintenance activities.

10.8. Reclamation Accommodations (V. 3.0 Ref #7)

Based on a review of the accommodation requirements to complete all reclamation work (excluding pit flooding and monitoring), the accommodation requirements have been increased to 244,550 person-days. A summary of the estimated person crew and corresponding person-days required for each year of reclamation is provided in Table 10.8-1. This new total includes the 16,030 person-days that was previously added to the estimate as part of the addition of the Jay Project, and an additional 11,520 person-days added for this latest estimate, based on revised estimates for crew needs over the reclamation period (also provided in Table 10.8-1). The additional 11,520 person-days represents an increase of $913,920 to the RECLAIM estimate.

Table 10.8-1 Reclamation Accommodations (excluding pit flooding)

Reclamation Year Person Crew Person-Days

Year 1 200 73,000

Year 2 170 62,050

Year 3 130 47,450

Year 4 100 36,500

Year 5 70 25,550

TOTAL 244,550

The accommodation total of 252,233 person-days included in the RECLAIM estimate includes the additional 9,683 person-days required for the pit flooding staff. The changes in accommodation requirements for the pit flooding program have been included as an item in the pit flooding optimization RECLAIM update (V. 3.0 Ref #4).

10.9. Scarifying and Vegetation (V. 3.0 Ref #8)

The most recent Ekati mine RECLAIM estimate, presented for the MUG Project, included an estimated total area of 358 ha that would require scarification, and a total area of 154 ha that would require seeding. Based on the inventory presented in Section 5.8, including data for the Ekati mine pads (Table 5.8-1) and roads (Table 5.8-3), new totals have been estimated. The new totals are 393 ha for scarification and 196 ha for seeding. This update represents an increase of $667,520 to the RECLAIM estimate.



A summary of the revised pad and road surface areas to be scarified and seeded is provided in Table 10.9-1. The areas were based on an assumption that 80% of the total disturbed area would be scarified, and 40% of the total disturbed area reseeded. The costing information for the roads (see Section 5.8.3) should be taken as preliminary, as reclamation options for the Ekati mine roads are in the process of being developed in the context of wildlife movement on roads.

Table 10.9-1 Scarifying and Seeding Areas

Total Area (ha)

Scarifying (ha)

Seeding (ha)

Pads

All developments excluding Jay 245 196 98

Jay development 21 17 8

Pad Total: 266 213 106

Roads

All developments excluding Jay 205 164 82

Jay development 20 16 8

Road Total: 225 180 90

TOTAL 491 393 196

10.10. Underground Reclamation (V. 3.0 Ref #9)

As a result of the planned closure and reclamation of the Panda/Koala Underground workings, more detailed engineering and inventory work has been completed. This has resulted in a corresponding update to the estimated costs for reclamation. The overall changes represent a decrease of $1,952,106 to the RECLAIM estimate. Provided below is an overall summary of the RECLAIM cost updates:

• Fresh air and return air raises—An updated unit cost of $78,843 for the blocking of the raise was developed. This updated estimate is based on the cost of third-party contractors installing pre-made concrete blocks that have been fabricated off site. This option presents savings of approximately $0.7 million from the previous preliminary estimate, which assumed that all concrete construction work would be completed on site.

• Panda/Koala surface portals—Based on a more developed understanding of the engineering requirements (as outlined in Mine Health and Safety Act [GNWT 2010]) for blocking the portals, a new unit cost of $64,000 per portal was developed. This change represented an overall decrease of approximately $0.8 million to the RECLAIM estimate.

• MUG surface portal—Both portals for the MUG development will be located below grade for Misery Pit, and hence the provisional cost for reclamation of one the surface portals has been removed from the estimate. This update represents an approximate decrease $0.5 million to the RECLAIM estimate.

• Panda/Koala hazardous waste material—Based on a review of the inventory of equipment in the Panda/Koala Underground working an additional 15,000 kg of waste batters and 50,000 L of waste that would require collection, shipment, and disposal off site has been added to the estimate. This change represents an approximately $36,000 increase to the RECLAIM estimate.



10.11. Security Phasing and Land Water Split

The future development costs for Jay, Sable Phase 3 and 4, and MUG are impacted by the proposed RECLAIM updates. Dominion has recalculated the future development costs based on the proposed RECLAIM updates. As requested by the GNWT, Dominion has continued to split the costs for land and water for Jay and MUG developments to facilitate posting of the land-related security cost under Ekati Diamond Mine Land Use Permits and the water-related security cost under Ekati Diamond Mine Water Licence. The overall modification of the respective Land Use Permits and change in Schedule 2 of the Water Licence will be facilitated after a determination on the security amounts is completed as part of the overall review process for ICRP Version 3.0.

10.11.1. Sable Phasing Schedule

The optimized pit flooding RECLAIM update (V. 3.0 Ref #4) resulted in increased costs for the flooding of Sable Pit, primarily driven by the increased fuel costs. This change has resulted in an increased cost for the remaining posting phases for the Sable development. Provided in Table 10.11-2 is the revised Sable phasing requirements compared to the 16 June 2016 WLWB reasons for decision for phase posting for the Sable Development (WLWB 2016). In total this represents an increase of $1,564,130.

Table 10.11-1 Sable Phase 3 and 4 Posting Schedule

Sable Posting Phase Revised ICRP Ver 3.0 WLWB June Determination

Phase 3: 20% of open pit mining, by volume $3,555,748 $2,780,000

Phase 4: 60% of open pit mining, by volume $2,848,382 $2,060,000

Total $6,404,130 $4,840,000

ICRP = Interim Closure and Reclamation Plan; WLWB = Wek'èezhı̀ı Land and Water Board.

10.11.2. Jay Land and Water Split and Phasing Schedule

A land and water split and security posting schedule for the Jay development was provided in the 2017 annual progress report (Dominion 2018e). Based on the pit flooding (V. 3.0 Ref #4) and demolition infrastructure (V. 3.0 Ref #5) RECLAIM updates, the proposed land and water splits and phasing schedule has been modified and is provided in Table 10.11-2. Overall, this represents an approximate increase of $445,121 for the total security allocated to the Jay development.

Table 10.11-2 Jay Development Phasing and Development

Jay Project Phase and Milestone Timeline

Revised ICRP Ver 3.0 2017 Progress Report

Total Land Water Total Land Water

Jay Early Works (2017–2019) $624,458 $624,458 $0 $1,435,999 $1,480,000 ($44,001) Phase 1: Dyke Construction (2019–2023) $6,786,895 $2,358,304 $3,573,049 $8,217,010 $3,411,888 $4,805,123 Phase 2: Open Pit Mining (2023–2034) $10,465,712 $7,582,559 $2,883,153 $7,778,935 $7,582,559 $196,375 TOTAL: $17,877,065 $10,565,321 $6,456,202 $17,431,944 $12,474,447 $4,957,497

Note: Numbers in parentheses and red font are decreases.

ICRP = Interim Closure and Reclamation Plan.



10.11.3. Misery Underground Land and Water Split

Provided in Table 10.11-3 is the revised split for land water cost for the MUG Project and the split provided by Dominion in its response to Information Request No. 7 as part of the MUG Water Licence Amendment (DDEC 2017o). The proposed underground reclamation RECLAIM update (V. 3.0 Ref #9) and the inclusion of the Misery Camp expansion results in an increase of $706,195 to total security allocated MUG development. This change is reflected in the land portion only where the security value has been increased from $691,281 to $1,397,476.

Table 10.11-3 Land and Water Split for Misery Underground Development

RECLAIM Item Revised ICRP Ver 3.0 MUG Water Licence Amendment IR No. 7

Land Cost Water Cost Land Cost Water Cost

Portal – bulkhead and cover entrance --- --- $362,904 ---

Cap fresh air raise – concrete cap $78,843 --- $158,358 ---

Lowering Misery Pit --- $326,336 --- $326,336

Hazardous waste removal $6,433 --- $6,433 ---

Jay Misery Camp buildings $981,500 --- ---

Subtotal Split: $1,066,776 $326,336 $527,695 $326,336

Subtotal Combined: $1,393,111 $854,031

Project management (5%) $4,264 $16,317 26,385 16,317

Engineering (5%) $4,264 $16,317 26,385 16,317

Health and safety plans / monitoring QA/QC (0.5%) $426 $1,632 $2,638 1,632

Bonding insurance (0.5%) $426 $1,632 $2,638 1,632

Contingency (20%) $17,055 $65,267 $105,539 65,267

RECLAIM Grand Total Split $1,397,476 $427,500 $691,281 $427,500

RECLAIM Grand Total Combined $1,824,976 $1,118,781

ICRP = Interim Closure and Reclamation Plan; MUG = Misery Underground; IR = Information Request; QA/QC = quality assurance / quality control.



References

Adamczewski JZ, Boulanger J, Croft B, Cluff D, Elkin B, Nishi J, Kelly A, D’Hont A, Nicholson C. 2009. Decline of the Bathurst Caribou Herd 2006-2009: a technical evaluation of field data and modeling. Draft technical report December 2009. Department of Environment and Natural Resources, Government of the Northwest Territories, Yellowknife, NWT, Canada.

Alberta Agriculture. 1988. Weeds of the Prairies. Alberta Environmental Centre, 209 pp.

Banci V, Hanks C, Spicker R, Atatahak G. 2006. Walking in the path of the caribou: knowledge of the Copper Inuit, Naonaiyaotit Traditional Knowledge Project Report Series, Vol. I Pitkohit: Heritage and Culture. Kitikmeot Inuit Association, Cambridge Bay and Kugluktuk, NU, Canada.

BHP and Dia Met (BHP Diamonds Inc. and DIA Met Minerals Ltd.). 1995. NWT Diamonds Project environmental impact statement. Yellowknife, NWT.

BHP and Dia Met. 2000. EKATI Diamond Mine: environmental assessment report for Sable, Pigeon and Beartooth Kimberlite Pipes. Submitted to MVEIRB by BHP Diamonds Inc. and DiaMet Minerals Ltd., April 2000.

BHP Billiton. 2011a. Ekati Diamond Mine, interim closure and reclamation plan. Submitted to Wek’èezhìi Land and Water Board. Dated August 2011. Project 0648-105-01, Report Version 2.4.

BHP Billiton. 2011b. Ekati Diamond Mine: wastewater and processed kimberlite management plan Version 2.0. Submitted to Wek’èezhìi Land and Water Board. Dated October 2011.

BHP Billiton. 2012. Ekati Diamond Mine, 2012 annual interim closure and reclamation plan progress report.

BHP Diamonds Inc. 2000. Environmental assessment report for Sable, Pigeon and Beartooth kimberlite pipes. April 2000.

Borcard D, Legendre P, Avois-Jacquet C, Tuomisto H. 2004, Dissecting the spatial structure of ecological data at multiple scales. Ecology 85:1826–1832.

Brown J. 1988. Patch use as an indicator of habitat preference, predation risk, and competition. Behavioral Ecology and Sociobiology. 22: 37–47.

Carlson JA, Ravenscroft PJ, Lavoie C, Cunning J. 2016. Ekati Diamond Mine Northwest Territories, Canada NI43-101 Technical Report. Yellowknife, NWT: Dominion Diamond Corporation.

CCME (Canadian Council of Minsters of the Environment). 2001. Canadian sediment quality guidelines for the protection of aquatic life. http://ceqg-rcqe.ccme.ca/download/en/317.

CCME. 2008. Canada-wide standards for petroleum hydrocarbons (PHC) in soil. Endorsed by CCME 30 April–1 May 2001; revised January 2008. https://www.ccme.ca/files/Resources/csm/phc_cws/phc_standard_1.0_e.pdf.

CCME. 2014. Canadian environmental quality guidelines. http://ceqg-rcqe.ccme.ca/en/index.html.

CDA (Canadian Dam Association). Dam safety guidelines 2007. Revised 2013.

http://ceqg-rcqe.ccme.ca/download/en/317

https://www.ccme.ca/files/Resources/csm/phc_cws/phc_standard_1.0_e.pdf

http://ceqg-rcqe.ccme.ca/en/index.html



Chocolate. G. 2015. What’aa- esker research project. With support from Tłı̨chǫ Department of Culture and Lands Protection, and the Kwe Beh Working Group.

CSA (Canadian Standards Association). 2010. Technical guide – infrastructure in permafrost: a guideline for climate change adaptation. CSA Reference Number: Plus 4011-10.

DDEC (Dominion Diamond Ekati Corporation). 2013a. Appendix A. 2013 community vegetation workshop summary. Dominion Diamond Ekati Corporation, Yellowknife, NWT, Canada.

DDEC. 2013b. Draft Ekati Diamond Mine 2013 Traditional Knowledge strategy. Dominion Diamond, Yellowknife, NWT, Canada.

DDEC. 2013c. 2013 Ekati Diamond Mine: closure and reclamation progress report. Prepared by Dominion Diamond Ekati Corporation. 30 December 2013.

DDEC. 2013d. Dominion Diamond Ekati Corporation’s Lynx Project, Application for Water Licence and Land Use Permit. Submitted to the Wek’èezhìi Land and Water Board, September 2013.

DDEC. 2013e. Old Camp closure and reclamation plan. Prepared by Dominion Diamond Ekati Corporation: Yellowknife, Northwest Territories. 30 December 2013

DDEC. 2013f. Project description: proposed development of the Lynx kimberlite pipe. Prepared by Golder Associates Ltd., September 2013.

DDEC. 2013g. Re: Request for information – Reclamation Security Estimate. Letter to Mark Cliffe-Phillips, Wek'èezhı̀ı Land and Water Board. http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20Security%20Review%20-%20Information%20Request%20-%20DDEC%20Response%20-%20Jun%204_13.pdf. 4 June 2013

DDEC. 2014a. Developer’s Assessment Report for the Jay Project. Prepared by Golder Associates Ltd., October 2014. Yellowknife, NWT, Canada.

DDEC. 2014b. Ekati Diamond Mine: Long Lake Containment Facility investigation 2013. Prepared by EBA Engineering Consultants Ltd. and ERM Consultants Ltd. for Dominion Diamond Ekati Corporation: Yellowknife, Northwest Territories.

DDEC. 2014c. Land Use Permit Application for Misery Powerline. Submitted to the Wek’èezhìi Land and Water Board. 22 May 2014.

DDEC. 2014d. Ekati Mine Misery Powerline. supplemental information for Land Use Permit Application W2014I0001. Submitted to the Wek’èezhìi Land and Water Board. 23 July 2014.

DDEC. 2014e. 2014 Ekati Diamond Mine closure and reclamation progress report. Yellowknife, NT. December 2014. 28 pp. + Appendices.

DDEC. 2015a. Ekati Diamond Mine: 2013 to 2014 LLCF reclamation research report. Prepared by Dominion Diamond Ekati Corporation: Yellowknife, Northwest Territories. May 2015.

DDEC. 2015b. Ekati Diamond Mine: 2015 closure and reclamation progress report. Prepared by Dominion Diamond Ekati Corporation: Yellowknife, Northwest Territories.

http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20Security%20Review%20-%20Information%20Request%20-%20DDEC%20Response%20-%20Jun%204_13.pdf





DDEC. 2016a. Ekati Diamond Mine: 2016 environmental impact report. Prepared for Dominion Diamond Ekati Corporation by ERM Consultants Canada Ltd.: Yellowknife, Northwest Territories.

DDEC. 2016b. Ekati Diamond Mine Northwest Territories Canada, NI 43-101 Technical Report prepared by Carlson J, Ravenscroft P, Lavoie C, and Cunning J.

DDEC. 2016c. Ekati Diamond Mine: 2015 LLCF reclamation research report. Prepared by Dominion Diamond Ekati Corporation: Yellowknife, Northwest Territories. April 2016.

DDEC. 2016d. Ekati Diamond Mine: 2016 closure and reclamation progress report. Prepared by Dominion Diamond Ekati Corporation: Yellowknife, Northwest Territories.

DDEC. 2017a. Re: Measure 6-5 Traditional Knowledge based caribou monitoring and mitigation. Submitted to Mackenzie Valley Environmental Impact Review Board and Wek'èezhı̀ı Land and Water Board. Dominion Diamond Ekati Corporation. http://reviewboard.ca/upload/project_document/EA1314-01_DDEC_Traditional_Knowledge_Elders_Group_measure_6-5_.PDF. 16 May 2017.

DDEC. 2017b. Traditional Knowledge management framework. Submitted to Mackenzie Valley Environmental Impact Review Board. Dominion Diamond Ekati Corporation. http://registry.mvlwb.ca/Documents/W2013L2-0002/Ekati%20Jay%20Project%20-%20Traditional%20Knowledge%20Management%20Framework%20-%20May%2016_17.pdf. 16 May 2017.

DDEC. 2017c. Caribou mitigation plan for the Jay Project. Prepared for Dominion Diamond Ekati Corporation by Golder Associates Ltd. http://reviewboard.ca/upload/project_document/EA1314-01_DDEC_Caribou_Mitigation_Plan_measure_6-2a.PDF. May 2017.

DDEC. 2017d. Air quality and emission monitoring and management plan for the Jay Project. Prepared for Dominion Diamond Ekati Corporation by Golder Associates Ltd. January 2017.

DDEC. 2017e. Wildlife effects monitoring plan for the Ekati Diamond Mine. Prepared for Dominion Diamond Ekati Corporation by Golder Associates Ltd. March 2017.

DDEC. 2017f. Traditional Knowledge Elders Group workshop summary report. 12 to 13 September 2017.

DDEC. 2017g. Traditional Knowledge Elders Group workshop summary report. 5 to 6 December 2017.

DDEC. 2017h. Jay Project EA annual report. June 2017. http://reviewboard.ca/upload/project_document/EA1314-01_DDEC_2017_JAY_EA_ANNUAL_REPORT_FINAL_30june2017__3_.PDF

DDEC. 2017i. EKA PRO 2104 spill contingency plan. Version 11.0. Submitted to WLWB 29 December 2017.

DDEC. 2017j. Workshop summary report: Traditional Knowledge Elders Group. 12–13 September 2017.

DDEC. 2017k. 2017. Misery Underground Project Water Licence Amendment and Land Use Permit Application Package – Appendix A: Misery Underground Project: Project Description. Prepared by Golder Associates Ltd. August 2017.

DDEC. 2017l. Wastewater and processed kimberlite management plan. Version 7.0. October 2017.

http://reviewboard.ca/upload/project_document/EA1314-01_DDEC_Traditional_Knowledge_Elders_Group_measure_6-5_.PDF

http://reviewboard.ca/upload/project_document/EA1314-01_DDEC_Traditional_Knowledge_Elders_Group_measure_6-5_.PDF

http://registry.mvlwb.ca/Documents/W2013L2-0002/Ekati%20Jay%20Project%20-%20Traditional%20Knowledge%20Management%20Framework%20-%20May%2016_17.pdf



http://reviewboard.ca/upload/project_document/EA1314-01_DDEC_Caribou_Mitigation_Plan_measure_6-2a.PDF

http://reviewboard.ca/upload/project_document/EA1314-01_DDEC_Caribou_Mitigation_Plan_measure_6-2a.PDF

http://reviewboard.ca/upload/project_document/EA1314-01_DDEC_2017_JAY_EA_ANNUAL_REPORT_FINAL_30june2017__3_.PDF

http://reviewboard.ca/upload/project_document/EA1314-01_DDEC_2017_JAY_EA_ANNUAL_REPORT_FINAL_30june2017__3_.PDF



DDEC. 2017m. Ekati Diamond Mine: 2016 LLCF reclamation research report. Prepared by Dominion Diamond Ekati Corporation: Yellowknife, Northwest Territories. July 2017.

DDEC. 2017n. Project Description: Misery Underground Project. Prepared by Golder Associates Ltd. August 2017.

DDEC. 2017o. Misery Underground Project – Information Request responses (#1–8). 15 December 2017

Dedats’eetssa. 2016. Ekwo zo gha dzo nats’ede. We live here for caribou. Cumulative Impact Study on the Bathurst Caribou. Tłîchô Traditional Knowledge and Land Use Study.

Dominion (Dominion Diamond Ekati ULC). 2018a. Ekati Mine engagement plan. Version 4.1. http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20Engagement%20Plan%20-%20Version%204.1%20-%20Jul%2027_18.pdf. July 2018.

Dominion (Dominion Diamond Ekati ULC). 2018b. Waste rock and ore storage management plan. Version 9.0. March 2018.

Dominion. 2018c. Aquatic effects monitoring program design plan for the Jay Project – construction and operations. Prepared for Dominion Diamond Ekati ULC by Golder Associates Ltd. March 2018.

Dominion. 2018d. Baseline data summary, evaluation, and adequacy. Prepared for Dominion Diamond Ekati ULC by Golder Associates Ltd. March 2018.

Dominion. 2018e. Ekati Diamond Mine 2017 closure and reclamation progress report. 22 January 2018.

Dominion. 2018f. Environmental Agreement and Water Licence annual report 2017. Prepared by Dominion Diamond Ekati ULC: Yellowknife, Northwest Territories.

Dredge LA, Ward BC, Kerr DE. 1994. Glacial geology and implications for drift prospecting in the Lac de Gras, Winter Lake, and Aylmer Lake Map Areas, Central Slave Province. Geological Survey of Canada 94-1C: 33–38.

EBA (EBA Engineering Consultants Ltd.). 2006a. Open pit flooding study, Ekati Diamond Mine. Prepared on behalf of BHP Billiton Diamonds Inc. August 2006.

EBA. 2006b. Thermal Evaluation of Waste Rock Piles, Ekati Diamond Mine. Report submitted to BHP Billiton Diamonds Inc., Project No. 0101-94¬11580.033, September 2006.

EBA. 2013. ICRP RP1.3 Task 3 – pit lake and channel elevations, Revision 1, Ekati Diamond Mine, NT. Prepared EBA, a Tetra Tech company, for DDEC. August 2013.

EcoSense (EcoSense Environmental Inc). 2018. Ekati Diamond Mine: 2017. Literature review regarding the suitability of stockpiled lake sediment as a reclamation substrate. Prepared for Dominion Diamond Ekati Corporation by EcoSense Environmental Inc.: Lethbridge, Alberta.

ERM (ERM Consultants Canada Ltd). 2014. Estimating the impacts of infilling Fox Pit (at closure) on Stream Connectivity Downstream of the Long Lake Containment Facility. September 2014.

ERM. 2015a. Ekati Diamond Mine: 2014 aquatic effects monitoring program summary report. Prepared for Dominion Diamond Ekati Corporation by ERM Consultants Canada Ltd.: Yellowknife, Northwest Territories.

http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20Engagement%20Plan%20-%20Version%204.1%20-%20Jul%2027_18.pdf

http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20Engagement%20Plan%20-%20Version%204.1%20-%20Jul%2027_18.pdf



ERM. 2015b. Ekati Diamond Mine: 2014 Pigeon Stream Diversion monitoring program - Volume I Technical Report. Prepared for Dominion Diamond Ekati Corporation by ERM Consultants Canada Ltd.: Yellowknife, Northwest Territories. February 2015.

ERM. 2016a. Ekati Diamond Mine: 2015 aquatic effects monitoring program re-evaluation and the proposed 2017 to 2019 AEMP plan. Prepared for Dominion Diamond Ekati Corporation by ERM Consultants Canada Ltd.: Yellowknife, Northwest Territories.

ERM. 2016b. Ekati Diamond Mine: waste rock storage area - closure screening level ecological risk assessment. Prepared for Dominion Diamond Ekati Corporation by ERM Consultants Canada Ltd.: Yellowknife, Northwest Territories.

ERM. 2016c. Ekati Diamond Mine: 2015 Pigeon Stream Diversion monitoring program - Volume I Technical Report. Prepared for Dominion Diamond Ekati Corporation by by ERM Consultants Canada Ltd.: Yellowknife, Northwest Territories.

ERM. 2016d. Caribou crossing photo and road features analysis 2011–2015. Prepared for Dominion Diamond Ekati Corporation by by ERM Consultants Canada Ltd.: Yellowknife, Northwest Territories

ERM. 2017a. Ekati Diamond Mine: aquatic effects monitoring program design plan for 2017 to 2019. Version 6.0. Prepared for Dominion Diamond Ekati Corporation by ERM Consultants Canada Ltd.: Vancouver, British Columbia.

ERM. 2017b. Ekati Diamond Mine: 2016 aquatic effects monitoring program. Prepared for Dominion Diamond Ekati Corporation. Yellowknife, NWT, Canada.

ERM. 2017c. Ekati Diamond Mine - Environmental Agreement and Water Licence annual report 2016. Prepared on behalf of Dominion Diamond Ekati Corporation.

ERM. 2017d. Ekati Diamond Mine: aquatic response framework. Version 2.0. Prepared for Dominion Diamond Ekati Corporation by ERM Consultants Canada Ltd.: Yellowknife, Northwest Territories.

ERM. 2017e. Ekati Diamond Mine: 2017 Koala watershed water quality model. Prepared for Dominion Diamond Ekati ULC by ERM Consultants Canada Ltd.: Yellowknife, Northwest Territories.

ERM. 2018a. 2014-2017 air quality monitoring program. http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%202017%20Air%20Quality%20Monitoring%20Program%20-%20Report%20-%20Jul%2027_18.pdf. 20 July 2018.

ERM. 2018b. 2017 Wildlife effects monitoring program. Prepared for Dominion Diamond Ekati ULC by ERM Consultants Canada Ltd.: Yellowknife, Northwest Territories.

ERM. 2018c. Ekati Diamond Mine: Sable aquatic effects monitoring program plan. Version 1.3. Prepared for Dominion Diamond Ekati ULC by ERM Consultants Canada Ltd.: Yellowknife, Northwest Territories.

ERM. 2018d. 2017 aquatic effects monitoring program. http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%202017%20Water%20Licence%20and%20EA%20Annual%20Report%20-%20Apr%2030_18.pdf. 20 April 2018.

http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%202017%20Air%20Quality%20Monitoring%20Program%20-%20Report%20-%20Jul%2027_18.pdf



http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%202017%20Water%20Licence%20and%20EA%20Annual%20Report%20-%20Apr%2030_18.pdf





ERM Rescan (ERM Rescan Environmental Services Ltd). 2013a. Ekati Diamond Mine: modelling predictions of water quality for pit lakes. Prepared for Dominion Diamond Ekati Corporation by Rescan Environmental Services Ltd.: Yellowknife, Northwest Territories.

ERM Rescan. 2013b. Modelling water quality and water quantity impact of infilling Fox Pit Lake with LLCF water. December 2013.

ERM Rescan. 2013c. 2013 Panda Diversion Channel Habitat Enhancements – Instream Vegetation and Habitat Structures. Memo prepared for Dominion Diamond Ekati Corporation by ERM Rescan.: Vancouver, British Columbia.

Gillespie B. 1981. Yellowknife. In Sturtevant W, Helm J (eds), Handbook of North American Indians: Vol. 6 Subarctic. Washington, DC, USA: Smithsonian Institute, pp 285-290.

GNWT (Government of Northwest Territories). 2010. Mine Health and Safety Act. SNWT 1994, c. 25, in force 15 December 1995; amendments to SNWT 2010, c. 16. Available at: https://www.justice.gov.nt.ca/en/files/legislation/mine-health-and-safety/mine-health-and-safety.a.pdf.

GNWT. 2014. Wildlife Act. S.N.W.T. 2014, c. 31. In force 31 October 2-17. https://www.justice.gov.nt.ca/en/files/legislation/wildlife/wildlife.a.pdf

GNWT-ENR (Government of the Northwest Territories – Environment and Natural Resources). 2018. Climate change. http://www.enr.gov.nt.ca/en/services/climate-change

GNWT Industry, Tourism and Investment (Government of the Northwest Territories Department of Industry, Tourism and Investment. 2008. History of mining in the Northwest Territories. Yellowknife, NWT. http://www.iti.gov.nt.ca/about-iti/copyright.shtml. Accessed July 2013.

Golder (Golder Associates Ltd.). 2015. Lynx Project: Lynx offsetting and fish-out plans. Prepared for Dominion Diamond Ekati Corporation. March 2015.

Golder. 2016a. Golder. 2016a. Jay Project - Water Licence water quality model updates. Submitted to Dominion Diamond Ekati Corporation. 2 June 2016.

Golder. 2016b. Jay conceptual closure and reclamation plan. Submitted to Dominion Diamond Ekati Corporation. 1 June 2016.

Golder. 2016c. Water quality modelling of seepage from waste rock storage areas. Prepared for Dominion Diamond Ekati Corporation by Golder Associates Ltd.

Golder. 2017. Ekati Mine - Misery Underground water quality model updates. Submitted to Dominion Diamond Ekati Corporation. 14 August 2017.

Golder. 2018a. Ekati Mine – Pit lake closure water quality modelling. Prepared for Dominion Diamond Ekati ULC. 17 January 2018.

Golder. 2018b. Ekati Mine – Supernatant water quality modelling of Panda, Koala, and Koala North pit lakes at closure. DRAFT Technical Memorandum to Annie Larrivée, Dominion Diamond Ekati ULC, from Shadi Dayyani and Jerry Vandenberg, Golder Associates. 10 August 2018.

https://www.justice.gov.nt.ca/en/files/legislation/mine-health-and-safety/mine-health-and-safety.a.pdf

https://www.justice.gov.nt.ca/en/files/legislation/wildlife/wildlife.a.pdf

http://www.enr.gov.nt.ca/en/services/climate-change

http://www.iti.gov.nt.ca/about-iti/copyright.shtml

http://www.iti.gov.nt.ca/about-iti/copyright.shtml



Golder. 2018c. Investigation of effective neutralization potential of waste rock at the Ekati mine. Technical memorandum prepared for Dominion Diamond Ekati ULC. 31 July 2018.

Gordon B. 1996. People of the sunlight, people of the starlight: barrenland archaeology in the Northwest Territories of Canada. Ottawa, ON: Canadian Museum of Civilization.

Government of Canada. 1985a. Fisheries Act. R.S.C., 1985, c. F-14. Last amended 5 April 2016. Current to 20 June 2018. http://laws-lois.justice.gc.ca/eng/acts/f-14/.

Government of Canada. 1985b. Navigation Protection Act. R.S.C., 1985, c. N-22. Last amended 22 June 2017. Current to 20 June 2018. http://laws-lois.justice.gc.ca/eng/acts/N-22/.

Government of Canada. 2002. Species at Risk Act. S.C. 2002, c. 29. Last amended 30 May 2018, current to 5 July 2018. http://laws-lois.justice.gc.ca/eng/acts/s-15.3/.

Government of Canada. 2018. Introduction to climate scenarios. Available at: http://climate-scenarios.canada.ca/?page=cmip5-intro.

Government of Canada, GNWT, and BHP (Government of Canada, Government of the Northwest Territories, and BHP Diamonds Inc.). 1997. Environmental Agreement. Yellowknife, NT, Canada.

Helm J. 1981. Dogrib. In Sturtevant W, Helm J (eds), Handbook of North American Indians: Vol. 6 Subarctic. Washington, DC, USA: Smithsonian Institute, pp 290-309.

Helmstaedt H. 2009. Crust-mantle coupling revisited: The Archean Slave Craton, NWT, Canada. Lithos 112S: 1055-1068.

Hoffman P. 1989. Precambrian geology and tectonic history of North America. In Bally AW, Palmer AR (eds). The Geology of North America-An Overview. Geological Society of America, Boulder, CO, USA, pp 447-512.

Johnson C, Seip D, Boyce M. 2004. A quantitative approach to conservation planning: Using resource selection functions to map the distribution of mountain caribou at multiple spatial scales. Journal of Applied Ecology. 41: 238–251.

Joint Venture. 2017. Tibbitt to Contwoyto Winter Road Joint Venture. Available at: http://www.jvtcwinterroad.ca/facts.html.

Kidd JD, Max KN. 2001. Ekati Diamond Mine, revegetation research projects, 2001, NT, Canada. Prepared for BHP Diamonds, Inc., Yellowknife, NT, by ABR Inc., Fairbanks, SK.

Kidd JD, Max KN. 2002. Ekati Diamond Mine, revegetation research Projects, 2002, NT, Canada. Prepared for BHP Diamonds, Inc., Yellowknife, NT, by ABR Inc., Fairbanks, SK.

Linnamae U, Clark BL. 1976. Archaeology of Rankin Inlet, N.W.T. The Muskox 19: 37-73.

LKDFN (Łutselk’e Dene First Nation), Drybones M, Drybones N, Catholique J, Desjardans V, Lockheart M, Marlowe P, Michel A, Michel J, Rabesca JB, Catholique M, Parlee B, Catholique B, Catholique L.1999. Habitats and wildlife of Gahcho Kué and Katth’I Nene. West Kitikmeot Slave Study. Yellowknife, NWT, Canada.

LKDFN, Parlee B, Basil M, Casaway N. 2001. Traditional Ecological Knowledge in the Kaché Tué Study Region. West Kitikmeot Slave Study. Yellowknife, NWT, Canada.

http://laws-lois.justice.gc.ca/eng/acts/f-14/

http://laws-lois.justice.gc.ca/eng/acts/N-22/

http://laws-lois.justice.gc.ca/eng/acts/s-15.3/

http://www.jvtcwinterroad.ca/facts.html



Łutselk’e Dene Elders and Land-Users, Ellis S, Basil M, Catholique B, Casaway N, Desjarlais S, Catholique S. 2002. Denesǫłıne Land-Use in the Eedacho Kué and Desnedhé Che Region Report #1: Traditional practice – the land of legend. Submitted to De Beers Canada Exploration and BHP Billiton Inc. Yellowknife, NWT, Canada.

Martens HE. 2013. Ekati Diamond Mine revegetation research projects – 2012. Prepared for BHP Billiton Diamonds, Inc., Yellowknife, NT, by Harvey Martens & Associates Inc., Calgary, AB.

Martens HE. 2014. Ekati Diamond Mine revegetation research projects – 2013. Prepared for BHP Billiton Diamonds, Inc., Yellowknife, NT, Canada by Harvey Martens & Associates Inc. Calgary, AB.

Maxwell MS. 1980. Archaeology of the Arctic and Subarctic Zones. Annual Review of Anthropology 9: 161-185.

Maxwell MS. 1985. Prehistory of the Eastern Arctic. Orlando, FL, USA: Arctic Academic Press.

McNamara JM, Houston AI. 1996. State-dependent life histories. Nature 380:215–221.

McGhee R. 2009. Why and when did the Inuit move to the eastern Arctic? In Maschner H, Mason H, McGhee R (eds), The Northern World AD 900-1400. Salt Lake City, UT, USA: The University of Utah Press, pp 155-163.

MEND (Mine Environment Neutral Drainage). 2009. 1.20.1 - Prediction manual for drainage chemistry from sulphidic geologic materials – 2 December 2009.

Merkle JA, Fortin D, Morales JM. 2014. A memory-based foraging tactic reveals an adaptive mechanism for restricted space use. Ecology Letters 17, 924–931.

Mineral Services Canada Inc. 2002. Bedrock geology of the Ekati claim block. Report prepared for BHP Billiton.

MVEIRB (Mackenzie Valley Environmental Impact Review Board). 2016. Report of Environmental Assessment and Reasons for Decision. Dominion Diamond Ekati Corp. Jay Project EA1314-01. 1 February 2016.

MVLWB (Mackenzie Valley Land and Water Board). 2013. Guidelines for the closure and reclamation of advanced mineral exploration and mine sites in the Northwest Territories. Mackenzie Valley Land and Water Board and Aboriginal Affairs and Northern Development Canada. November 2013.

MVLWB. 2014. Engagement guidelines for applicants and holders of Water Licences and Land Use Permits. Mackenzie Valley Land and Water Board, Gwich’in Land and Water board, Sahtu Land and Water Board, Wek'èezhı̀ı Land and Water Board. September 2014.

Nielsen SE, Boyce MS, Stenhouse GB, Munro RHM. 2003. Development and testing of phenologically driven grizzly bear habitat models. Ecoscience 10:1–10.

Noble WC. 1981. Prehistory of the Great Slave Lake and Great Bear Lake Region. In Sturtevant W, Helm J (eds), Handbook of North American Indians: Vol. 6 Subarctic. Washington, DC, USA: Smithsonian Institution, pp 97-106.

Nowicki T, Crawford B, Dyck DR, Carlson JA, McElroy R, Oshust PA, Helmstaedt H. 2004. The geology of kimberlite pipes of the Ekati claim block, Northwest Territories, Canada. Lithos, v.76, pp 1–28.

NWTMN (Northwest Territories Métis Nation). 2012. Gahcho Kue Mine Project Values, Interests, and Issues Identified at NWT Métis Nation Community TK Study Sessions. NWTMN, Fort Smith, NWT, Canada.



Oldham MJ, Delise-Oldham M. 2017. Report on the 2016 survey of exotic plants along Northwest Territories Highways. Government of the Northwest Territories, MNRF Science. https://www.enr.gov.nt.ca/sites/enr/files/resources/report_on_the_2016_survey_of_exotic_plants_along_northwest_territories_h.pdf. March 2017.

Pienitz R, Smol JP, Lean DRS. 1997. Physical and chemical limnology of 24 lakes located between Yellowknife and Contwoyto Lake, Northwest Territories (Canada). Can J Fish Aquat Sci 54:347-358.

Prowse TD, Furgal C, Bonsai BR, Edwards TWD. 2009a. Climatic conditions in Northern Canada: past and future. Ambio 38:257–265.

Prowse TD, Furgal C, Bonsai BR, Peters DL. 2009b. Climate impacts on northern Canada: regional background. Ambio 38:248–256.

Prowse TD, Furgal C, Melling H, Smith SL. 2009c. Implications of climate change for northern Canada: the physical environment. Ambio 38:266–271.

Rescan (Rescan Environmental Services Ltd.). 2006a. Summary report Ekati Diamond Mine archaeological and heritage site management 1994 to 2006. Yellowknife, NWT: BHP Billiton Diamonds Inc.

Rescan (Rescan Environmental Services). 2006b. Ekati wildlife and human health risk assessment final report. Report prepared for BHP Billiton Diamonds Inc. by Rescan Environmental Services: Yellowknife, Northwest Territories.

Rescan. 2007. EKATI Diamond Mine: Panda Diversion Channel monitoring program 2006. Volume 1 – Technical Report. Prepared for BHP Billiton Diamonds Inc. by Rescan Environmental Services Ltd. February 2007.

Rescan. 2010. 10-Year Panda Diversion Channel Monitoring Program Summary. Report prepared for BHP Billiton Canada Inc. by Rescan Environmental Services Ltd.: Vancouver, B.C.

Rescan. 2011. EKATI Diamond Mine: preliminary designs of reclaimed pit lakes. Prepared for BHP Billiton Canada Inc. by Rescan Environmental Services Ltd.: Vancouver, British Columbia.

Rescan. 2012a. EKATI Diamond Mine: Panda Diversion Channel Monitoring Program Final Report. Prepared for BHP Billiton Canada Inc. by Rescan Environmental Services Ltd.: Yellowknife, Northwest Territories.

Rescan. 2012b. 2012 Panda Diversion Channel: Proposed Habitat Enhancements. Prepared for BHP Billiton Canada Inc. by Rescan Environmental Services Ltd.: Vancouver, British Columbia.

Rescan. 2013. EKATI Diamond Mine: 2012 Aquatic Effects Monitoring Program Summary Report, Version 1.1. Prepared for BHP Billiton Canada Inc. by Rescan Environmental Services Ltd.: Yellowknife, Northwest Territories.

Robertson GeoConsultants. 2005. Multiple accounts analysis of the optimization options for the Ekati Long Lake Containment Facility. Robertson GeoConsultants Report No. 023003/2.

Sadownik L, Harris H. 1995. Dené and Inuit Traditional Knowledge: a literature review. Edmonton, AB: Canadian Circumpolar Institute, University of Alberta.

Smith E, Rogers J. 1981. Environment and culture in the Shield and Mackenzie Borderlands. In Sturtevant W, Helm J (eds), Handbook of North American Indians: Vol. 6 Subarctic. Washington, DC: Smithsonian Institute, pp 130-144.

https://www.enr.gov.nt.ca/sites/enr/files/resources/report_on_the_2016_survey_of_exotic_plants_along_northwest_territories_h.pdf

https://www.enr.gov.nt.ca/sites/enr/files/resources/report_on_the_2016_survey_of_exotic_plants_along_northwest_territories_h.pdf



SRK (SRK Consulting [Canada)] Inc.). 2007. Ekati Diamond Mine geochemical characterization and metal leaching (ML) management plan. Prepared for BHP Billiton Diamonds Inc. August 2007.

Tetra Tech EBA. 2014a. Pigeon Pit Waste Rock Storage Area Design, Ekati Diamond Mine, NT.

Tetra Tech EBA. 2014b. Completion report Panda Diversion Channel stabilization. Ekati Diamond Mine, NT. Prepared for Dominion Diamond Ekati Corporation. October 2014.

Tetra Tech EBA. 2016. Thermal evaluation of Panda/Koala, Misery, coarse PK, and Fox waste storage areas, Ekati Diamond Mine, NT. Prepared for Dominion Diamond Ekati Corporation. E14103219-04. May 2016.

Tetra Tech. 2017. Pigeon waste rock storage area updated design report. Revision 1. Ekati Diamond Mine, NT. Prepared for Dominion Diamond Ekati Corporation. E14103068-13. 19 October 2017.

Tetra Tech. 2018. Sable waste rock storage area. Letter from Tetra Tech Canada Inc. to Annie Larrivee, Dominion Diamond Ekati ULC. 25 July 2018.

Tłı̨chǫ Government. 2014. Monitoring Results. Boots on the Ground Caribou Monitoring Program. Tlicho Traditional Knowledge and Land Use Study. Tlicho Government. Behchoko, NT, Canada

Tłı̨chǫ Research and Training Institute. 2013. Traditional Knowledge study for Diavik soil and lichen sampling program. Cited in Tłı̨chǫ Government. 2016. Tłı̨chǫ Government intervention – Jay Project EA1214-001. November 2016.

Weledeh Yellowknives Dene. 1997. Weledeh Yellowknives Dené: A Traditional Knowledge study of Ek'ati. Dettah, NWT: Yellowknives Dene First Nation Council.

Whitson TD (ed.), Burrill LC, Dewey SA, Cudnet DW, Nelson BE, Lee RD, Parker R. 2009. Weeds of the West – 10th Edition. Western Society of Weed Science, Las Crices, New Mexico. 628 pp.

WLWB (Wek'èezhı̀ı Land and Water Board). 2013. Security Review – Reasons for Decision. http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20Security%20Review%20-%20Amendment%20of%20Water%20Licence%20Schedule%202%20-%20RFD%20-%20June%2017_13.pdf. 17 June 2013.

WLWB. 2014. Re: DDEC Old Camp closure and reclamation plan (OCCRP). 26 April 2014.

WLWB. 2015. Re: DDEC’s 2014 Closure and Reclamation Plan Progress Report and Security Review. http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20CRP%20-%202014%20Annual%20Progress%20Report%20-%20Board%20Directive%20and%20Reasons%20for%20Decision%20-%20June%2012_15.pdf. 12 June 2015.

WLWB. 2016. Request to Phase Posting of Security for the Sable Development – decision from Wek'èezhı̀ı Land and Water Board meeting of June 8, 2016. http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20Sable%20-%20Phasing%20of%20Security%20-%20Board%20Directive%20and%20Reasons%20for%20Decision%20-%20Jun%2016_16.pdf. 16 June 2016.

WLWB. 2017. Water Licence W2012L2-0001 (Amendment to incorporate Ekati Jay Project). Issued to Dominion Diamond Ekati Corporation. 6 July 2017.

http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20Security%20Review%20-%20Amendment%20of%20Water%20Licence%20Schedule%202%20-%20RFD%20-%20June%2017_13.pdf



http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20CRP%20-%202014%20Annual%20Progress%20Report%20-%20Board%20Directive%20and%20Reasons%20for%20Decision%20-%20June%2012_15.pdf



http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20Sable%20-%20Phasing%20of%20Security%20-%20Board%20Directive%20and%20Reasons%20for%20Decision%20-%20Jun%2016_16.pdf





WLWB. 2018. Reasons for Decision. Land Use Permit and Water Licence Application for the Ekati Misery Underground Development. http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20Water%20Licence%20-%20Amendment%20-%20Misery%20UG%20-%20RFD%20and%20Recommendation%20to%20Minister%20-%20Jul%2012_18.pdf. 12 July 2018.

http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20Water%20Licence%20-%20Amendment%20-%20Misery%20UG%20-%20RFD%20and%20Recommendation%20to%20Minister%20-%20Jul%2012_18.pdf



https://ddcorp.sharepoint.com/news-events-site/Templates/DD_Ekati%20Report%20Option1_08NOV17.docx

Ekati Mine Interim Closure and Reclamation Plan Version 3.0 Appendix A: Glossary August 2018



Appendix A Glossary of Terms and Definitions

Acid rock drainage (ARD) The production of acidic leachate, seepage, or drainage from underground workings, ore piles, waste rock, processed kimberlite, and overburden that can lead to the release of acidic water to groundwater and surface water during the life of the mine and after mine closure.

Active layer The top layer of the ground, above the permafrost table, that thaws each summer and refreezes each fall.

Adaptive management A formal process of formulating and continually improving resource management policies and practices by learning from the outcomes of operational programs.

Amendment An addition of materials to existing substrate that modifies texture and nutrient potential, with the intent of encouraging plant growth through improvement of soil condition. Examples of amendments are organic matter (compost, alfalfa pellets), till, and fertilizer.

Angle of repose The maximum slope at which a heap of any loose or fragmented solid material will stand without sliding or come to rest when poured or dumped in a pile or on a slope.

Anthropogenic Coming from or caused by man.

Aquatic Growing or living in or frequenting water; occurring or situated in or on water.

Aquatic Effects Monitoring Program (AEMP) A monitoring program designed to determine the short- and long-term effects in the Receiving Environment resulting from the Project; evaluates the accuracy of impact predictions, assesses the effectiveness of planned impact mitigation measures, and identifies additional impact mitigation measures to reduce or eliminate environmental effects.

Archaeological site A location exhibiting physical signs of past human use, typically greater than 50 years in age.

Arctic A geographic region in the northern hemisphere that is circumpolar in extent and generally characterized as being north of the treeline, in an area of continuous permafrost.

Armouring Placement of material on/in a channel or pond to protect against erosion.

As-built (drawings) Engineering drawings portraying a site as constructed/reclaimed, including all changes from the original design that were implemented during construction and/or reclamation.

Backfill Mine waste or rock used to fill the void created by mining an ore body.

Barrenlands/Barrengrounds The area of the Northwest Territories east of the Mackenzie River valley and north and east of the treeline characterized by a low rolling tundra landscape, continuous permafrost, and low densities of human settlement.

Baseline studies Initial scientific investigations that determine the present ecological state of an area and establish a basic reference necessary for further mandatory studies once development begins.

Bedrock The solid rock under organic soil, gravel, till, or loose boulders. May also be exposed at ground surface, with no cover.

Bench (open pit) Material is removed from open pit mines in successive layers called benches. A bench is a ledge that forms a single level of operation above which materials are excavated from a continuous bank face.

Benthic Pertaining to the bottom region of a waterbody, such as a lake.

Benthic invertebrates Invertebrate organisms that live on the bottom of a lake, creek, or the ocean.

Benthos Assemblage of organisms living in or on the bottom sediments of a waterbody and dependent upon the decomposition cycle for most, if not all, of its basic food supply.

Berm A linear shaped earth or rockfill barrier. Typically constructed to impede access by vehicles, people, or wildlife.

Bioaccumulation The process by which chemicals build up in organisms from sources in food and water.

Biodiversity The variety of organisms found within a specific geographic region.

Biomass The total mass of living organisms, usually expressed as a weight per unit area or volume (e.g., g/m3).

Broadcast seeding Scattering seed on the surface of the soil. Contrasted with drill seeding, which places seed in rows below the soil surface.



Chemical stability Tendency of a material to resist change or decomposition. Mine waste deposits are considered chemically stable when surface waters and groundwater are protected against significant adverse effects resulting from discharges of water that contacts the mine waste. Adverse effects are those that could endanger public and wildlife health and safety, or result in unacceptable deterioration of environmental resources.

Clay 1. A soil type consisting of particles 0.002 mm in equivalent diameter. 2. A soil textural class containing >40% clay, <45% sand, and <40% silt.

Climate change A gradual increase in the average temperature of the Earth's atmosphere generally attributed to the greenhouse effect caused by increased levels of carbon dioxide, chlorofluorocarbons, and other pollutants.

Closure The actions carried out when a mine ceases commercial production to bring the site to a safe and stable condition for the long term after mining.

Closure criteria Criteria which define specific performance requirements for progressive reclamation and closure of mine components. They are also used to determine success of reclamation and the completion of monitoring programs (e.g., Water Licence Discharge criteria).

Closure objective Describes what the reclamation activities intend to achieve. Objectives must be achievable and measurable.

Coagulants Chemicals added to wastewater to break emulsions and cause coagulation of particles. Used in water treatment plants.

Coarse Processed Kimberlite (CPK) Coarse material, as defined in the approved Wastewater and Processed Kimberlite Management Plan, rejected from the processing plant after the recoverable diamonds have been extracted.

Community (plants and animals) Populations of plants or animals living and interacting with one another in a given area.

Concentration A measure of the amount of a substance present per unit volume or per unit weight of material.

Conceptual Pertaining to a preliminary idea, plan, and/or strategy with generalized statements. A conceptual closure plan is used when a mine is many years away from completion, decommissioning, and reclamation.

Connate water Water that is trapped in the pores of a rock during the rock’s formation. The chemistry of the water can change throughout the history of the rock. Connate water at the Ekati mine is found below the permafrost.

Consolidation The gradual reduction in volume of a material resulting from a compressive stress (including its own weight). The adjustment of a saturated soil in response to a load involves the squeezing of water from pores and an increase in bulk density.

Contaminant A general term referring to any chemical compound added to a Receiving Environment in excess of natural conditions. The term also includes materials not generally regarded as “toxic,” such as nutrients, salts, and colour.

Contaminated Snow Containment Facility A lined area set aside within the waste rock storage areas for the containment of snow and ice that is contaminated by hydrocarbons as approved in the Hydrocarbon Management Plan.

Contingency An action or plan put in place in preparation to remediate or remove a risk that is not certain to occur.

Core A sample taken from a rock formation for geological analysis.

Crusher A machine used to reduce materials such as kimberlite ore to particle sizes where diamonds can be found.

Cubic metre (m3) A unit of volume measurement that is equivalent to the volume occupied by one tonne of water. Waste rock, processed kimberlite, and kimberlite ore are usually measured in cubic meters.

Cultivars Plant material that has been commercially propagated and/or bred.

Cuttings Sections of shrub stems capable of rooting and growing into independent plants when placed in appropriate media.

Decommissioning The process of permanently removing equipment, buildings, and structures.

Detection limit The smallest amount of a substance that can be detected by a given analysis method.

Diabase A common basic igneous rock (also known as dolertite or microgabbro), typically found in volcanic intrusions.

Diamond An extremely hard crystalline form of carbon, often used as a gemstone or for cutting.



Dike An engineered embankment barrier constructed primarily of earthen materials and designed to retain water and/or flowable waste materials. In geological usage, the word is also used to identify a sheet of rock that forms in a fracture that cuts across the structure of a pre-existing rock body.

Discharge A volume of water flowing a given measuring point at a given place and time. Flow leaving a pipe or a stream cross-section.

Drainage patterns The form in which surface water flows in a watershed (i.e., the form of ditches, creeks, streams and rivers).

Drilling Vertical perforations of the ground surface. Used for resource exploration, site investigation, or for loading explosives.

Dust suppressants Products and techniques used to minimize dust emissions from surfaces (such as roads or fine processed kimberlite).

Ecology The study of the interactions between organisms and their environment.

Ecosystem A community of interacting organisms considered together with the chemical and physical factors that make up their environment.

Effect A change to a species, ecosystem, or region. An effect is not necessarily a negative impact; an effect may be neutral, or even positive.

Effluent Treated or untreated waste water that is discharged into the environment.

Emissions Gases going into the atmosphere (such as car exhaust, chemicals).

Encapsulate To bury and/or cover over a material so that it is not exposed to the outside environment.

Environment The components of the Earth including land, water, air, and all layers of the atmosphere. Also all organic and inorganic matter and living organisms and the interacting natural systems including the cultural, social, and spiritual components.

Environmental Agreement An agreement between the governments of Canada and the Northwest Territories and Dominion. The Environmental Agreement was created to address environmental concerns that were not covered by existing legislation and regulations at the time of initial permitting of the Ekati mine in 1996.

Environmental Impact Statement (EIS) The document prepared by BHP Minerals Inc. and dated 24 July 1995, including the Additional Information Request of 19 December 1995, the Environmental Impact Statement updates of 15 December 1995, and the Environmental Baseline Study—all of which were submitted by BHP Minerals Inc. to the Federal Environmental Assessment Review Panel.

Environmental Site Assessment A process by which a property is assessed to identify areas, type, and volume of soil contamination. There are three phases that may be applied. A site only progresses to the next phase if contamination is noted in the previous phase.

• Phase 1: historical review and site inspection • Phase 2: intrusive investigation to determine potential areas of environmental

concern • Phase 3: delineation of the spatial extent and volume of contamination

Ephemeral stream Streams where surface water flow is not always measurable. These streams could become dry seasonally (e.g., every summer), or only occasionally (once every 10 years).

Erosion The wearing away of rock, soil, or other surfaces by water, ice, or wind.

Esker A winding ridge of weakly stratified gravel and sand deposited by a stream flowing in (or beneath) the ice of a retreating glacier, and left behind when the ice melted. Often used as a travel corridor and insect relief for caribou.

Euphotic zone The upper portion of the water column where adequate light is present for photosynthesis to occur.

Exploration The search for mineral deposits and the work done to prove or establish the extent of a mineral deposit.

Explosives Any rapidly combustive or expanding substance. The energy released during this rapid combustion or expansion is used to break rock in mining operations

Extraction The process of mining and removal of ore from a mine.

Feasibility The stage in mining or reclamation when the selected option is rigorously evaluated to finalize the scope, budget, and timeline; engineered drawings are developed (if required), the risks and opportunities are established, and a clear defined plan of how the reclamation will be executed are put in place.

Fertilizer Compounds added to the soil to correct nutrient deficiencies. The main purpose is to add nitrogen, phosphorus, and potassium to the soil. These are the main nutrients that plants need to grow.



Fine processed kimberlite (FPK) Fine material, as defined in the approved Wastewater and Processed Kimberlite Management Plan, rejected from the processing plant after the recoverable diamonds have been extracted.

Flocculants Chemicals that are used to combine colloids and other suspended particles in liquids to form larger particles. Flocculants are used in water treatment processes across Canada to improve the sedimentation or filterability of small particles.

Forb A broad-leaved herb other than a grass, especially one growing in a field or prairie, or on tundra.

Fresh air raise Shaft constructed to bring fresh air from surface to underground workings.

Freshet The increased flow of water over a relatively short period of time, during spring, caused by snowmelt.

Fugitive dust Any airborne, uncontrolled particulate matter generated from open sources.

Geochemistry The study of chemical properties of rocks.

Geotechnical Of, or pertaining to, practical applications of geological science in civil engineering and mining.

Geotechnical stability Resistance of an earthen structure to major movements that could impede its ability to meet its design function.

Geology The science concerned with the study of the rocks that compose the Earth.

Geomorphic Relating to the form of the landscape and other natural features of the Earth's surface.

Glacial till Accumulations of unsorted, unstratified mixtures of clay, silt, sand, gravel, and boulders that are deposited on the land as a glacier recedes. Till is the usual composition of a moraine.

Granite A hard, crystalline igneous rock, typically containing quartz, mica, and feldspar.

Greenhouse gas Any of various gases, especially carbon dioxide, that contribute to trapping the sun’s warmth in the Earth’s lower atmosphere

Groundwater All water below the ground surface. Shallow groundwater is water that occupies pores and crevices in the rock and soil of the active layer above the permafrost layer. Deep groundwater is ancient fossil or connate water that occupies pores and crevices in the bedrock below the permafrost layer.

Habitat Any area that provides food, water and/or shelter for an organism.

Haul road A road built to carry heavy trucks.

Hazardous material Chemicals that are persistent and toxic, with the potential to cause undesirable consequences under certain conditions.

Highwall (open pit) The unexcavated face of exposed overburden and/ or bedrock in a surface mine, located on the uphill side of a contour mine excavation.

Hydrocarbons A family of chemical compounds containing carbon and hydrocarbon atoms in various combinations, found especially in fossil fuels.

Hydrocarbon-contaminated soil Soil materials that have been contaminated with hydrocarbons.

Hydrology The study of the properties of water and its movement in relation to land.

Indigenous Native to, or originating, produced, growing, or living naturally in a particular region or environment.

Infrastructure The basic structural installations used for mining operations (e.g., roads, buildings, water supply, and sewage treatment facilities).

Invertebrates A collective term for all animals without a backbone or spinal column. Includes insects, worms, clams, snails, spiders.

Kame A ridge mound of stratified sands and gravels left by a retreating ice sheet.

Kimberlite A rock of igneous origin that is forced towards the Earth's surface via volcanic pipes and often contains diamonds. The name is derived from Kimberley, South Africa, where the rock was first discovered.

Kimberlite pipe A more or less vertical, cylindrical ore body of kimberlite that resulted from the forcing of the kimberlite material to the Earth's surface.

Kimberlite stockpile A temporary accumulation or surplus of ore built up when demand slackens, when the processing plant is temporarily unable to handling the mine output, when a reserve is required for future loading, or for other purposes.

Lake sediment Sediment that settles to the bottom of lakes and is removed from drained lake bottoms prior to mining underlying kimberlite pipes.



Lake dewatering The removal of all water from a natural waterbody or the portion of a natural waterbody enclosed by engineered structures.

Land Use Permit An authorization required for an activity set out in Sections 4 and 5 of the Mackenzie Valley Land Use Regulations, or a Land Use Permit (Type C) required by Tłı̨chǫ law for use of Tłı̨chǫ lands for which a Type A or Type B Land Use Permit is not required.

Landfarm Comprises the lined and engineered facility that is designed to contain and treat, using bioremediation, hydrocarbon-contaminated sediments and soil with an average diameter of less than 4 cm.

Landfill A waste management facility designed for disposal of specified solid wastes.

Leaching Chemicals being “washed” out of the rock by water.

Legume A member of the legume or pulse family, Leguminosae. One of the most important and widely distributed plant families with the ability to fix nitrogen from the air to the benefit of associated plants. Includes species such as clovers, alfalfas, lespedezas, and vetches.

Lichen Any plant organism composed of a fungus and an alga in symbiotic association, usually of green, grey, or yellow tint and growing on and colouring rocks, tree trunks, roofs, walls.

Life of Mine (LOM) Plan The current schedule for future development and operation of the proposed mine, which is reviewed and updated on an ongoing basis.

Limnology The study of fresh water lakes, including biological, geological, physical, and chemical aspects.

Littoral Region of a lake from the highest water level to the depth at which photosynthesis ceases, usually within the top 10 m.

Meromictic A condition in which a lake does not mix completely and contains permanently stratified layers. The boundaries in a meromictic lake separate an upper layer from a deeper and denser layer or layers. Stratification can be caused by thermal (temperature) and/or density differences (e.g., salinity).

Metasediments Sedimentary rocks that have been modified by metamorphic processes.

Migration The regular seasonal movements of birds and animals to and from different areas.

Mine component A physical area of the mine site treated as an independent unit for reclamation planning and application of reclamation objectives and closure criteria.

Mine site The area of land that is owned, accessed or leased, under recognized mineral licences, for mineral extraction, on-site processing, waste treatment, and storage.

Minewater Minewater includes runoff from facilities associated with the Ekati mine and all water or waste pumped or flowing out of any open pit or underground mine.

Mitigation An activity aimed at avoiding, controlling, or reducing the severity of adverse physical, biological, and/or socioeconomic impacts of an activity.

Model A physical or numerical tool that uses concept information to explain or describe a complex phenomenon.

Monitoring Observing, quantifying (where possible), and recording changes to a specific area, feature, or ecosystem component on a regularly scheduled basis, using a suite of appropriate parameters.

Natural colonization The process of revegetation of a disturbed area by naturally dispersing seeds, spores, or vegetative propagules from local plant populations.

Nutrient Any substance that provides essential nourishment for the maintenance of life.

Oligotrophic Low-nutrient waters with low primary productivity. The vast majority of Arctic lakes in the Ekati area are oligotrophic.

Open pit mine A mine where excavation happens on the surface.

Organic matter The organic fraction of the soil that includes plant and animal residues at various stages of decomposition, cells and tissues of soil organisms, and substances synthesized by the soil population.

Overburden material Layers of soil, till, and lake sediments covering an ore body that are removed prior to surface mining.

Panda Diversion Channel (PDC) A 3.4 km artificial stream that connects the northern basin of Upper Panda Lake to Kodiak Lake. Completed in 1997, this channel provides compensation for fish habitat lost as a result of mine development.

Parameter A constant or variable in a mathematical expression that distinguishes various specific situations.

Particulates Small liquid or solid particles in the air such as dust pollen, spores, soot, smoke, or spray.



Permafrost A layer of soil, sand, or bedrock that has been continuously frozen for at least two years and as long as ten thousand years. In the tundra area at the Ekati mine, permafrost begins at the bottom of the active layer (approximately 1.5 m deep) and continues to approximately 400 m.

pH The pH scale is generally presented from 1 (most acidic) to 14 (most alkaline). It measures the hydrogen ion concentration of a substance.

Physical stability An area that has no significant wind and water erosion and is geotechnically stable.

Plant cover The percentage of substrate in any area that is covered by living plant biomass.

Porewater Water that is contained within rocks, soils or processed kimberlite.

Portal The structure surrounding the immediate entrance to an underground mine.

Predator Any organism that consumes other organisms.

Processing plant Where the diamonds are extracted from excavated kimberlite rock.

Processed Kimberlite (PK) Material rejected from the processing plant after the recoverable diamonds are extracted.

Processed kimberlite containment areas (PKCA) Those locations at which processed kimberlite may be deposited, as approved by the Wek'èezhıı̀ Land and Water Board.

Professional Engineer A person who is registered with the Northwest Territories and Nunavut Association of Professional Engineers and Geoscientists in accordance with the Engineering and Geoscience Professions Act. S.N.W.T. 2006, V.16, or subsequent editions, as a professional engineer, and whose principal field of specialization is appropriate to address the components of the project at hand.

Progressive reclamation Reclamation of individual mine site disturbances that takes place prior to final closure of the mine site.

Quarry A surface excavation for sourcing construction rock or sand materials.

Qualified professional Term to refer to a professional with sufficient accredited training and experience in their discipline that they may practise independently. If there is a professional licencing body for the area of practice, they must be licenced to practice. If there is a licensing body in the Northwest Territories, they must be licensed by that body.

Receiving Environment The natural aquatic environment that receives any deposit or Discharge of waste, including seepage or minewater, from the mine.

Reclamation Activities which facilitate the return of affected areas to viable and, wherever practicable, self-sustaining ecosystems that are compatible with a healthy environment, human activities, and the surrounding environment.

Reclamation goal The goal of reclamation is to return the Ekati mine site to viable, and wherever practicable, self-sustaining ecosystems that are compatible with a healthy environment, human activities, and the surrounding environment.

Reclamation option Possible reclamation activities that are evaluated against each other to identify which is preferred.

Residual effects Effects that persist after mitigation measures have been applied.

Return air raise Shaft constructed to remove spent air from underground workings to the surface.

Revegetation Introduction of new vegetation by seeding, planting, or natural colonization on disturbed or barren ground.

Riparian Areas adjacent to streams and watercourses that support vegetation that is adapted to changing water levels.

Risk A factor, thing, element, or course involving uncertain hazard to people, wildlife, or the environment.

Risk assessment Reviewing risks for a given site, component, or condition.

Runoff Water that is not absorbed by soil and drains off the land into bodies of water.

Run-of-mine Rock that is utilized at the size excavated from a blast without further size reduction or screening.

Salvageable materials Materials or equipment recovered from the dismantling or demolition of a plant, buildings, or structures that can be removed from the site and economically sold, recycled, or reused in another location.

Scarification Decompacting and roughening of a soil surface to create an irregular surface. This is often done to restore natural infiltration characteristics to the ground surface, and to facilitate seeding or planting by enabling better seed to soil contact, root penetration, and moisture retention.



Sedimentation pond A containment structure for minewater so that sediments can settle and are prevented from being transported into the Receiving Environment.

Seepage The process of water moving through porous materials, including soils, waste rocks, and kimberlite. Also used to refer to the water discharged to the Receiving Environment as a result of this process.

Soil The loose, uncemented minerals and organic material on the immediate surface of the Earth that serves as a natural medium for the growth of land plants.

Source lake A lake from which water is removed over a period of time and used for potable water, processing water, and flooding open pits in reclamation or other purposes.

Species A group of highly similar plants or animals that is part of a genus and are geographically isolated, or can reproduce fertile offspring only among themselves.

Stratification Forming or depositing in layers in water and on the land.

Subsidence The gradual sinking, or sometimes abrupt collapse, of the rock and soil layers above deposited material or over an underground mine. Structures and surface features above the subsidence area can be affected.

Substrate In the context of reclamation, this refers to mineral materials forming the ground surface and implies that the original soil material is no longer present.

Surface water Water (including snow and ice) on the ground or in a stream, river, lake, or ocean.

Sustainability Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

Talik Unfrozen zones that can exist within, below, or above permafrost layers. They are usually located beneath deep waterbodies.

Temporary closure When a mine temporarily delays, or puts on hold, operations with the intent of resuming activities in the future.

Terms of Reference Instructions that ensure the required information is provided.

Thermokarst Characteristic landforms result from the thawing of ice-rich permafrost.

Thermistor An electrical resistor used for measurement of temperature. Often used in geotechnical engineering to monitor the internal temperature of the ground, waste rock storage areas, dams, and bedrock.

Till Unstratified rock material deposited directly by glaciers, consisting of a mixture of clay, silt, sand, gravel, and boulders ranging widely in size and shape.

Topsoil The original upper soil layer, usually containing organic matter, and used as a growth medium for reclamation.

Total dissolved solids (TDS) The concentration of dissolved ions (principally calcium, magnesium, potassium, sodium, bicarbonate, chlorides, and sulphates) in a known volume of water (typically measured in mg/L).

Total suspended particulates (TSP) Airborne particles with a diameter of less than 30 µm, and recorded as micrograms per cubic meter of air (µg/m3).

Total suspended solids (TSS) The weight of solids suspended in a known volume of water (typically measured mg/L).

Toxicity The inherent potential or capacity of a material to cause adverse effects in a living organism.

Traditional Knowledge (TK) A cumulative body of knowledge, values, and beliefs, handed down from one generation to another that has been learned through experience and observation from the land and from oral tradition.

Trend The discernable tendency in a measured variable over time.

Tributary streams Streams feeding, joining, or flowing into a larger stream.

Tundra Habitat typically found in the Arctic, north of the treeline, that is adapted to cold temperatures, a short growing season, and low precipitation.

Underground mine An excavation underground to extract ore or minerals.

Vascular plant Plants that have true roots, leaves, and stems and an internal structure capable of actively taking up water and nutrients from the soil (e.g., trees, grasses, and shrubs). These plants are also capable of transporting products derived from the sun through the plant.

Waste rock All unprocessed rock materials that are produced as a result of mining operations.

Water balance An equation used to describe the movement of water in and out of a system. For any system, the difference between the water entering and leaving the system is the change in storage.

Water Licence A Type A or Type B licence permitting the use of waters or the deposit of waste, or both, issued under Section 26 of the Northwest Territories Waters Act.



Watershed A region or area bordered by ridges of higher ground that drains into a particular watercourse or waterbody.

Weathering The natural process that breaks down rock and other substrate by wind and water.

Wetland A swamp, marsh, or other land that is usually water-saturated.


Ekati Mine Interim Closure and Reclamation Plan Version 3.0 Appendix B: Acronyms and Abbreviations August 2018



Appendix B List of Acronyms, Abbreviations, Units, and Symbols

Abbreviations

Abbreviation Definition

AANDC Aboriginal Affairs and Northern Development Canada

ABA acid base accounting

AEMP Aquatic Effects Monitoring Program

ANFO ammonium nitrate fuel oil

AQEMMP Air Quality and Emissions Monitoring and Management Plan

ARD acid rock drainage

ASTt Arctic Small Tool tradition

BP Before Present

CALA Canadian Association for Laboratory Accreditation

CAM continuous air monitoring

CCME Canadian Council of Ministers of the Environment

CKR Coarse kimberlite rejects

CKRSA coarse kimberlite reject storage area

Closure Guidelines Guidelines for the Closure and Reclamation of Advanced Mineral Exploration and Mine Sites in the Northwest Territories

CMIP5 Coupled Model Intercomparison Project Phase 5

CO2e carbon dioxide equivalent

the Company Domininon Diamond Mines ULC

COSEWIC Committee on the Status of Endangered Wildlife in Canada

CPK coarse processed kimberlite

CSA Canadian Standards Association

CWS Canada-Wide Standards

DAR Developer’s Assessment Report

DDMI Diavik Diamond Mines (2012) Inc.

De Beers De Beers Canada Inc.

DFO Fisheries and Oceans Canada

DKFN Deninu Kue First Nation

Dominion Dominion Diamond Ekati ULC

EA Environmental Assessment

EBA EBA Engineering Consultants Ltd.

ECCC Environment and Climate Change Canada

EIA Environmental Impact Assessment

EIR Environmental Impact Review

EIS Environmental Impact Statement

Ekati mine Ekati Diamond Mine

EQC Effluent Quality Criteria

ENR Environment and Natural Resources

ERM ERM Consultants Canada Inc.

ERT emergency response team

ESP exchangeable sodium percentage




FPK fine processed kimberlite

FRMC Fort Resolution Métis Council

GHG greenhouse gas

GNWT Government of the Northwest Territories

Golder Golder Associates Ltd.

HCT Humidity cell testing

HDPE high-density polyethylene

IBA Impact Benefit Agreement

IACT Inter-agency Coordinating Team

ICRP Interim Closure and Reclamation Plan

IEMA Independent Environmental Monitoring Agency

INAC Indigenous and Northern Affairs Canada

ISO International Organization for Standardization

KIA Kitikmeot Inuit Association

KPSF King Pond Settling Facility

KWR kimberlite waste rock

LKDFN Lutsel K’e Dene First Nation

LLCF Long Lake Containment Facility

LOM Life of Mine

MGOM mine-generated organic material

MK magmatic kimberlite

ML metal leaching

MUG Misery Underground

MVEIRB the Mackenzie Valley Environmental Impact Review Board

MVLWB Mackenzie Valley Land and Water Board

n/a not applicable

Narrows Lac du Sauvage – Lac de Gras Narrows

NDVI Normalized Difference Vegetation Index

NOX oxides of nitrogen

non-PAG non-potentially acid generating

NP neutralization potential

NP/AP neutralization potential/acid potential

NPRI National Pollutant Release Inventory

NRCan Natural Resources Canada

NSMA North Slave Métis Alliance

NWT Northwest Territories

PAG potentially acid generating

PK processed kimberlite

PKCA processed kimberlite containment area

PM10 particulate matter with a mean aerodynamic diameter of 10 microns (µm) or smaller

PM2.5 particulate matter with a mean aerodynamic diameter of 2.5 microns (µm) or smaller

PVK primary volcaniclastic kimberlite

PSD Pigeon Stream Diverstion

RCP Representative Concentration Pathway

REA Report of Environmental Assessment and Reasons for Decision

ROM run of mine




RVK resedimented volcaniclastic kimberlite

SAR sodium adsorption ratio

SD standard deviation

SNAP Scenarios Network for Alaska + Arctic Planning

SNP Surveillance Network Program

SO2 sulphur dioxide

sp. species

spp. multiple species

TBD to be determined

TCWR Tibbitt to Contwoyto Winter Road

TDS total dissolved solids

Tetra Tech Tetra Tech Inc.

TK Traditional Knowledge

TKEG Traditional Knowledge Elders Group

TOC total organic carbon

TSP total suspended particulate

TSS total suspended solids

VK volcanoclastic kimberlite

VOCs volatile organic compounds

WEMP Wildlife Effects Monitoring Program

WLWB Wek'èezhıı̀ Land and Water Board

WRAF Waste Rock Storage Area Closure Risk Assessment Framework

WROMP Waste Rock and Ore Storage Management Plan

WRSA waste rock storage area

YKDFN Yellowknives Dene First Nation



Units of Measure

Unit Definition

% percent

< less than

> greater than

°C degrees Celsius

cm centimetre

eq/ha/yr equivalent per hectare per year

Ga giga-annum or billion years ago

ha hectare

kg kilogram

kg CaCO3/t kilograms of calcium carbonate equivalent per tonne of material

Kg/ha Kilograms per hectare

km kilometre

km2 square kilometre

km/h kilometres per hour

kt kilotonne

kW kilowatt

L litre

m metre

m2 square metre

m3 cubic metre

m/s metres per second

m3/s cubic metres per second

m3/yr cubic metres per year

Ma mega-annum or million years ago

masl metres above sea level

mg/dm2/d milligrams per square decimetre per day

mm millimetre

MW megawatt

V volt


Ekati Mine Interim Closure and Reclamation Plan Version 3.0 Appendix C: Record of Engagement August 2018



Appendix C Record of Engagement

2016-2014 Ekati Site Visits

Date Stakeholder / Affected Party & Participants Dominion/Consultant Participants Description

23 Sept 2014 Wek'èezhı̀ı Land and Water Board (WLWB) Elissa Berril Environment and Natural Resources (ENR) Kate Witherly Government of Northwest Territories (GNWT) Gerald Enns Environment Canada (EC) Sarah-Lacey McMillan Brad Summerfield, Fisheries and Oceans Canada (DFO) Veronique D’Amours Julie Marentette Mackenzie Valley Environmental Impact Review Board (MVEIRB) Chuck Hubert, Sachi DeSouza Independent Environmental Monitoring Agency (IEMA) Kevin O’Reilly Tim Byers

Lukas Novy Claudine Lee Eric Denholm Nicole Spencer Harry O'Keefe Gary Koop Wilf Petherbridge

Inter-Agency Coordinating Team (IACT Site Visit) Visit focused on providing stakeholders with update on Ekati reclamation projects including Cell B LLCF reclamation and research and Old Camp Reclamation.

11 June 2014 Independent Environmental Monitoring Agency (IEMA) Bill Ross Tim Byers Jaida Ohokannoak Tony Pearse Arnold Enge Kevin O'ReillyJessica Simpson Kim Poole

Chantal Lavoie Rick Bargery Claudine Lee Eric Denholm Nicole Spencer Kate Shea Harry O’Keefe Charles Klengenberg Lukas Novy Nick Ballantyne

Site visit to Cell B LLCF reclamation area.

10 June 2014 Wek'èezhı̀ı Land and Water Board (WLWB) Elissa Berril Environment and Natural Resources (ENR) Lionel Marcinkoski Mary Tapsell Joel Holder Laurie McGregor Brad McInnes Shelly Acton David Jessiman Matt Seaboyer Environment Canada (EC) Sarah-Lacey McMillan Dave Fox Fisheries and Oceans Canada (DFO) Veronique d’Amours-Gauthier Francois Larouche Independent Environmental Monitoring Agency (IEMA) Kevin O'Reilly

Chantal Lavoie Rick Bargery Claudine Lee Eric Denholm Nicole Spencer Kate Shea Jamie Steele Harry O’Keefe Jamie Steele Andrew Howton Charles Klengenberg Lukas Novy

Site visit to Cell B LLCF reclamation research area and the Panda Diversion Slope Stabilization.



Date Stakeholder / Affected Party & Participants Dominion/Consultant Participants Description

10 June 2014 Tłı̨chǫ – Behchoko 12 total members including 11 students and 1 chaperone

Claudine Lee Corey Champion Stephanie Lloyd Dave Clarke Joe Hatch John Bekale

Site visit to Cell B LLCF reclamation research area

4 June 2014 Tłı̨chǫ Government Members Including: Michel Moosenose, Freddy Flunkie, Liza Mackenzie, Larry Barens, and 6 students

Rick Bargery, Charles Klengenberg Helen Larocque, Lukas Novy


4 June 2014 Yellowknives Dene First Nation (YKDFN) Chief Edward Sangris Chief Ernest Betsina Alfred Baillargeon Jonas Sangris Napoleon Mackenzie

Chantal Lavoie Claudine Lee Charles Klengenberg


3 June 2014 Tłı̨chǫ – Gameti Chief David Wedawin Garry Bekale Alfred Arrowmaker Charlie Gon Jenny Arrowmaker Borris Eyakfwo Julian Black

Richard Bargery Keith Sangris John Bekale Rebecca Plotner Lukas Novy Shannon Hayden (Golder)




Date Stakeholder / Affected Party and Participants Dominion/Consultant Participants Description

24-27 Aug 2015 Yellowknives Dene First Nation (YKDFN) Modeste Sangris Paul Mackenzie Morris Martin Lena Drygeese Alexander Power Lutsel K'e Dene First Nation (LKDFN) August Enzoe Terri Enzoe North Slave Métis Alliance (NSMA) Lawrence Mercredi Shirley Coumont Caleigh Matheson Carson James Shin Shiga

Charles Klengenberg Harry O’Keefe Laura Corey Jeffery Mantla Cody Drygeese Lukas Novy Nick Ballantyne Wilf Petherbridge (EcoSense) Christine Rock (ERM)

Site visit of LLCF Reclamation Research Area

17-20 Aug 2015 Kitikmeot-Inuit-Association (KIA) Mona Tiltalik (Interpreter) Mark Taletok Jack Ayaligak Bobby Algona Gustin Adjun Tłı̨chǫ James Rabesca Moise Rabesca Michelle Rabesca Charlie Football Charlie Gon Garry Bekale

Charles Klengenberg Laura Corey Nick Ballantyne Harry O’Keefe


21 July2015 Lutsel K'e Dene First Nation (LKDFN) Iris Catholique Roger Catholique Berna Catholique Brian Sanderson Peter Unger

Harry O'Keefe Nick Ballantyne


15 July 2015 Wek'èezhı̀ı Land and Water Board (WLWB) Elissa Berril Mackenzie Valley Environmental Impact Review Board (MVEIRB) Sachi De Souza Environment Canada (EC) Sarah-LaceyMcMillan Independent Environmental Monitoring Agency (IEMA) Douglas Doan Kevin O’Reilly Environment and Natural Resources (ENR) Kate Witherly Matt Seaboyer Government of Northwest Territories (GNWT) William Pain Melissa Pink

Claudine Lee Laura Malone Nicole Spencer Luke Novy

Inter-Agency Coordinating Team (IACT Site Visit) Visit focused included site visit to LLCF Reclamation Research Areas.



Date Stakeholder / Affected Party and Participants Dominion/Consultant Participants Description

6 July 2015 Fort Resolution Metis Council (FRMC) Teri Mae Beaulieu Trudy King Violet Mandeville Deninu K'ue First Nation (DKFN) Alma Mandeville Dave Pierrot Mae Sayine Myranda Calumet

Harry O'Keefe Nick Ballantyne




Date Stakeholder / Affected Party and Participants DDEC/Consultant Participants Description

15 June 2016 Independent Environmental Monitoring Agency (IEMA) Jaida Ohokannoak Kim Poole Emory Paquin Tim Byers Doug Doan Arnold Enge Jesse Jasper Jessica Simpson Marc Casas

April Hayward Harry O’Keefe Laura Corey Lukas Novy David Bruce Allister McCreadie (Videographer)

Site visit of Beartooth Pit and LLCF Reclamation Research Area

18-19 Oct 2016 Deninu K'ue First Nation (DKFN) Dave Pierrot Patrick Simon Fort Resolution Métis Council (FRMC) Lena McKay Edward Balsillie Lutsel K'e Dene First Nation (LKDFN) August Enzoe Joe Lockhart Terri Enzoe Roger Catholique James Marlowe Yellowknives Dene First Nation (YKDFN) Modeste Sangris Morris Martin Napoleon Mackenzie Berna Martin Alexander Power

Charles Klengenberg Ori Wah-Shee Laura Corey Nick Ballantyne Rebecca Plotner Jeffery Mantla David Childs Joseph Poirier


19-20 Oct 2016 Kugluktuk Community Mark Taletok Jack Analigak Randy Hinanik Doyle Algona Jorgen Bolt North Slave Métis Alliance (NSMA) Wayne Langenhan Lawrence Mercredi Shirley Coumont Carson James Tłı̨chǫ Government Frank Arrowmaker Garry Bekale Charles Football

Charles Klengenberg Ori Wah-Shee Laura Corey Nick Ballantyne Rebecca Plotner Jeffery Mantla David Childs Joseph Poirier




ICRP Ver 3.0 Feb 27-28 Workshop Meeting Minutes

MEETING MINUTES

DATE 27 to 28 February 2018 Project Ekati Interim Closure and Reclamation Plan

LOCATION Yellowknife, NWT Meeting Purpose 2-Day Engagement Workshop

Meeting Chair: Kristine Mason, Golder

Record Keeper: Transcribed; summarized by Donna Venzi, Golder

Attendees: 27 February 2018: Dominion Diamond Ekati ULC (Dominion): April Hayward, Lukas Novy, Annie Larrivée, Harry O’Keefe, Lynne Boettger EDenholm Consulting: Eric Denholm Golder Associates Ltd. (Golder): Björn Weeks, Lisa Kempenaar ERM: Jason Rempel, Christine Rock Independent Environmental Monitoring Agency (IEMA): Emery Paquin, Bill Slater, Marc Cassas, Shannon Moore Government of Northwest Territories – Department of Environment and Natural Resources (GNWT, ENR): Paul Green, Bill Payne Fisheries and Oceans Canada (DFO): Jessica Taylor North Slave Métis Alliance (NSMA): Nicole Goodman Kitikmeot Inuit Association (KIA): Wynter Kuliktana, Monica Anghiatok Hamlet of Kugluktuk: Peter Taktagon, Bobby Anavilok Lutsel K’e Dene First Nation (LKDFN): Ray Griffith, August Enzoe Tłįchǫ Government: Joseph Judas, Phoebe Rabesca Fort Resolution Métis Council (FRMC): Shawn McKay, Wilfred Beaulieu Deninu Kué First Nation (DKFN): Stanley Louie Wek'èezhı̀ı Land and Water Board (WLWB): Meghan Schnurr

28 February 2018: Dominion: April Hayward, Lukas Novy, Annie Larrivée, Harry O’Keefe EDenholm Consulting: Eric Denholm Golder: Björn Weeks, Mike Paget, Mike Herrell, Kristin Salzsauler, Matt Neuner (by phone) ERM: Jason Rempel TetraTech: Gary Koop, Gordon Zhang IEMA: Emery Paquin, Bill Slater, Marc Cassas, Shannon Moore, Kevin Morin GNWT, ENR: Paul Green, Bill Payne DFO: Jessica Taylor KIA: Wynter Kuliktana, Monica Anghiatok Hamlet of Kugluktuk: Peter Taktagon, Bobby Anavilok LKDFN: Ray Griffith, August Enzoe Tłįchǫ Government: Joseph Judas, Phoebe Rabesca FRMC: Shawn McKay, Wilfred Beaulieu DKFN: Stanley Louie WLWB: Meghan Schnurr, Patty Ewaschuk (by phone), Anneli Jokela

DOMINION DIAMOND EKATI ULC

900 - 606 4 Street SW, Calgary, AB, Canada, T2P 1T1 T 1.403.910.1933 F 1.403.910.1934 www.ddcorp.ca

EKATI INTERIM CLOSURE AND RECLAMATION PLAN DATE: 27 to 28 February 2018 2-DAY ENGAGEMENT WORKSHOP

Agenda Items Item Owner

27 February 2018 – Day One

1 Welcome, H&S, Introductions, Meeting Objectives Kristine Mason

2 ICRP Background Information Eric Denholm

3 Approach & Changes for 2018 ICRP Update Version 3.0 Björn Weeks

4 Pit Closure and Littoral Zones Jason Rempel

5 Site-Wide Caribou Engagement Christine Rock

6 Site Wide Caribou Breakout Session Christine Rock

7 Traditional Knowledge Luke Novy

8 Next Steps, Wrap-Up, and Closing Comments Kristine Mason

28 February 2018 – Day Two

1 Welcome, H&S, Introductions, Meeting Objectives Kristine Mason

2 Operational Status of WRSAs and ICRP WRSA Closure Objectives Luke Novy

3 Information and Commitments for WRSA Closure Planning and Updated WRSA Reclamation Studies Eric Denholm

4 Pigeon WRSA Management Approach and Closure Cover Design Annie Larrivée, Kristin Salzsauler, Gary Koop

5 Next Steps, Wrap-Up, and Closing Comments Kristine Mason

2 DOMINION DIAMOND EKATI ULC



Day One Items for Discussion

Welcome, H&S, Introductions, Meeting Objectives

• Welcome and health and safety (H&S) items. • Overview of agenda and goals for the workshop.

ICRP Background Information

• Eric (EDenholm) gave an overview of the Ekati mine Interim Closure and Reclamation Plan (ICRP). • Original interim closure plan submitted in mid-1990s when the Ekati mine was first permitted. The ICRP

being prepared is an update to the revised ICRP (Version 2.4) submitted in 2011. • The ICRP update (Version 3.0) will include the Misery Underground Project, should it be approved. • Each of the individual components at the Ekati mine (e.g., pits, processing facilities) have existing

closure plans. Viability of the reclaimed sites is specifically spoken to in the closure plans and in the associated Water Licence.

• Reclamation measures at the Long Lake Containment Facility include rock and vegetation placement to mitigate erosion.

• The Old Camp Phase 1 and the Processed Kimberlite Containment Area (PKCA) have been reclaimed through removal of surface facilities, removal of kimberlite pond to the Long Lake Containment Facility, soil remediation (removal of contaminated soils), and scarification.

• Updates to the ICRP between 2011 and now have been made through the submission of the Annual Progress Reports.

• The revised ICRP due in July 2018 will incorporate new projects and project updates made since 2011. • Ray (LKDFN) noted that caribou recovery seems to be one of the biggest environmental issues at the

Ekati mine. Eric (EDenholm) noted that there are research projects related to caribou, that wildlife criteria will be a consideration in the ICRP, and that an upcoming presentation would speak directly to caribou.

• Ray (LKDFN) asked how hydrocarbon contaminated soils were disposed of. Luke (Dominion) said that large materials (>4 cm) were disposed of within the rock piles (i.e., were part of the closure landscape) and fines go to the landfarm treatment facility.

• Joseph (Tłįchǫ Government) expressed concern for the closure landscape’s ability to sustain wildlife and to return to pre-disturbance population levels. Eric (EDenholm) noted that an upcoming presentation would speak directly to caribou.

• Emery (IEMA) asked if a report will be issued after completion of the Old Camp reclamation to compare the actual reclamation against the planned objectives. Luke (Dominion) indicated that this was a good idea and suggested that a report of this nature may be tied to the reclamation security deposit for site components.

• Emery (IEMA) asked if previous progressive reclamation efforts have been addressed in the ICRP. Björn (Golder) confirmed that past progressive reclamation will be summarized in the document and that this is a regulatory requirement.

• Shawn (FRMC) asked about the financial security deposit, noting that it is not clear whether Dominion will need to make future payments (e.g., to cover Jay after construction is complete). Luke (Dominion) noted that the staged approach for security deposit payments is addressed in the most recent (2017) Annual Progress Report.

• Shawn (FRMC) also stated concern with caribou. April (Dominion) indicated that Dominion has similar concerns related to caribou and that an upcoming presentation would speak directly to caribou.

• Bobby (Hamlet of Kugluktuk) asked how the pits would be closed and how Dominion would reduce risks to wildlife getting trapped or injured in the pits. Luke (Dominion) stated that the pits would be filled with water (pit lakes) and that pit closure will be addressed in a later presentation.

• Shawn (FRMC) asked what “traditional knowledge” pertained to, and was it meant to address specific Aboriginal knowledge. Luke (Dominion) indicated that traditional knowledge (TK) is information shared by TK Holders of Aboriginal community groups.

Approach & Changes for 2018 ICRP Update Version 3.0

• The project has been updated and components added and changed since the 2011 ICRP was prepared.

• The 2018 ICRP will closely follow the guidance provided by the revised guidelines for the development of closure of reclamation plans, released by the Mackenzie Valley Land and Water Board in 2013.

• Using a site-wide approach to wildlife rather than component-by-component is a new approach in the 2018 ICRP.

• Björn (Golder) gave an overview of the proposed report structure: o introduction o environmental setting o project description o progressive reclamation o temporary closure o integrated schedule of activities o post-closure site assessment





• Permanent closure and reclamation plans will describe site components, pre-existing conditions, and closure objectives.

• The 2018 ICRP will include recently approved projects (i.e., Jay and Lynx) and also will be prepared under the assumption that the Misery Underground Project (currently in the approval process) will be approved.

• Lisa (Golder) gave an overview of closure and reclamation research projects at Ekati: o conceptual design o identification of gaps o risk analysis o research program design o research program implementation o design optimization

• Post-closure conceptual design was categorized by key questions (e.g., how is Dominion ensuring sufficient post-closure water quality?).

• Wilfred (FRMC) requested to see a list of the hazardous materials/chemicals used for operations. Wilfred was concerned about bioaccumulation of contaminants in wildlife, particularly caribou. He indicated that he felt there was a link between accumulation in wildlife and cancer rates in the community of Fort Resolution. He also noted declines in caribou populations and talked to effects of dewatering and fish-outs on local fish populations, including potential for new contaminants and diseases to spread. Luke (Dominion) thanked Wilfred for the input and noted that safe handling of chemicals and liquids brought on site was an important consideration to Dominion.

• Shawn (FRMC) requested that wildlife habitat should be added to the ICRP research focus areas and that aquatic communities and benthic invertebrates should be monitored under the water quality component. April (Dominion) confirmed that these items have been considered and agreed that this was a good point.

Pit Closure and Littoral Zones

• Jason (ERM) gave an overview of how open pits at the site will be flooded and turned into pit lakes at closure.

• Some pits (e.g., Fox Pit) will be flooded and be deep (~300 m). Other pits (e.g., Koala, Panda pits) will be filled with some of the processed kimberlite, which will reduce the depth (30 to 60 m). The Jay Pit will be under Lac du Sauvage.

• Flooding the pits will address safety (e.g., falling risks) and will assist in returning the area to pre-disturbance or equivalent capability.

• Littoral zones / shallow habitat will be established around the perimeter of selected pits to help support aquatic ecosystems.

• Establishment of littoral zones was discussed in the 2011 ICRP—risks remain around the use of the zones by aquatic species and establishing littoral zones in closed ecosystems. The littoral zones will be designed with engagement with DFO.

• Outfall design will be dependent on each pit and where it sits within the watershed. In most cases, it will be possible to reconnect the outfall channel to the stream that naturally flowed through the area pre-disturbance.

• Some cliff faces will be retained in pit lakes, which may provide raptor nesting habitat. • The 2011 ICRP did not identify which pits might be best suited for littoral zones. The 2018 ICRP will

consider the unique characteristics of each pit and rank the likelihood of successfully establishing littoral zones. This will establish a framework for future reclamation design.

• An unidentified speaker indicated that he/she thought the best approach to reclamation was to return the flooded pits to pre-disturbance conditions (i.e., replicating contours and outflow areas). Jason (ERM) confirmed that one goal of reclamation would be re-establishing outflow connectivity.

• Jess (DFO) asked about the level of engagement with DFO. Jason (ERM) indicated that DFO had been engaged during preparation of the 2011 ICRP, that there will be future need to engage DFO on the closure plan for each pit, and that ongoing engagement is part of the approval conditions.

• Jess (DFO) asked if processed kimberlite will be moved to Jay before the pit is flooded. Jason (ERM) indicated that there are no plans to store kimberlite at Jay as it is located within a large lake system and will not have the same conditions as the other pits after flooding.

• Jess (DFO) asked about the example pit shown. Jason (ERM) confirmed that it was the Beartooth Pit and that the littoral zone in the example shown was approximately 50 m before drop-off.

• Peter (Hamlet of Kugluktuk) asked about how long it would take to fill the pits and when the water from the pits would begin interacting with the environment. Luke (Dominion) stated that the water quality would be monitored during filling and in a designated period after a pit is completely filled. Water quality information will be shared with communities and other stakeholders.

• Bobby (Hamlet of Kugluktuk) asked about cleanup of abandoned exploration sites, specifically an exploration camp near Kugluktuk. Wynter (KIA) indicated that the camp Bobby enquired about had just undergone remediation and that final inspection would take place next summer.





• Phoebe (Tłįchǫ Government) asked how long pits would be monitored after they were filled. Luke (Dominion) indicated that the length of time depends on the conditions at the pit. A default 10-year monitoring period was specified in the 2011 ICRP. Actual monitoring durations will depend on factors at each pit, mostly related to water quality. A shorter monitoring time may be sufficient if water quality is meeting expectations; more time may be needed if challenges are encountered during flooding.

• Peter (Hamlet of Kugluktuk) asked about water quality monitoring at discharge points into the larger watershed. April (Dominion) noted that Dominion committed to a community-based Water Quality Monitoring Program in Kugluktuk as part of the Jay Environmental Assessment.

• Shawn (FRMC) asked about the plan for reclaiming the Jay Pit and which pits were under consideration for littoral zones. Kristine (Golder) noted Lac du Sauvage will provide the littoral habitat for the Jay Pit after breaching of the dike and that the remnants of the dike would provide potential spawning and rearing habitat for fish. Luke (Dominion) indicated that all of the pits, with the exception of Jay, are being considered for potential littoral zone work.

• Shawn (FRMC) requested that additional reclamation be considered at Jay to re-establish high quality forage and spawning habitat. He also asked if re-establishing littoral zones would be sufficient for fish habitat. April (Dominion) noted that Dominion has completed offsetting work associated with fisheries productivity loss for Jay and for other pits originally located under lakes. Jay Pit is located in deep habitat and is not littoral habitat specifically. At the present time, it is not known how fish will respond to the closure pit lakes. This was addressed through offsetting. April did state that there is hope that re-establishing the littoral zones will attract fish to the reclaimed pit lakes.

• Joseph (Tłįchǫ Government) provided context for the existing lakes and landscape from a Tłįchǫ perspective. He expressed concern about where the water to flood the pits would come from and doubt that animals and fish would return to constructed pit lakes and he expressed concern for contamination from mining materials and blasting debris. He also expressed concern about approvals and conditions around returning materials and water to the pit lakes. Luke (Dominion) indicated that the plan for flooding the pits was to use water from nearby lakes at a rate that would not impact the lake. The flooding would take place over a period of years and also include natural recharge (i.e., precipitation and runoff).

• Joseph (Tłįchǫ Government) proposed that there should be opportunities for the communities to monitor flooding of the pit. He noted that the Colomac mine was flooded and then he has not returned. Joseph expressed concern that the pits at the Ekati mine could overflow and affect wildlife migration. Luke (Dominion) thanked him for his statement.

• Phoebe (Tłįchǫ Government) asked what studies had been conducted prior to flooding Beartooth Pit and asked if there were any Aboriginal groups or agencies who visited the Old Camp site before, during, or after cleanup. April (Dominion) noted that Beartooth Pit is still operational and has not entered closure. The visual provided in the meeting was conceptual. April stated that Dominion has found site visits valuable and that she appreciated Joseph and Phoebe’s (Tłįchǫ Government) comments regarding site visits before, during, and after closure. Luke (Dominion) noted that in any areas where water or processed kimberlite is going into an area, all hazardous waste materials are removed. This has been done at Beartooth.

• Peter (Hamlet of Kugluktuk) indicated disagreement with filling the pits and connecting lakes and asked about potentially leaving the pits in their current form. Eric (EDenholm) thanked him for his input.

• Shawn (FRMC) asked about the temperature of the water that will be used to fill the pits and expressed concern at using warmer water over cooler water. April noted that the pits would be filled using precipitation and nearby lake water. The temperature in the water column is expected to be similar to other deep lakes (e.g., Grizzly Lake). Luke (Dominion) noted that water will be taken from lakes during non-frozen conditions and that lines used to move water would not need to be heated.

• Ray (LKDFN) asked about washing walls of the pits and pit conditions prior to flooding in relation to potential downstream water contamination. Luke (Dominion) indicated that wall washing happens during freshet. Luke noted that Dominion has modelled pit flooding through natural precipitation, pit flooding using water from adjacent lakes, and water levels after the pit has flooded to final elevation. The constant flow of water down the walls and out of the pit would behave similar to a natural lake. The composition of the pit walls (e.g., granite, metasediment) factor into water quality.

• Emery (IEMA) thanked Dominion for updating the ICRP and noted that the mine plan has advanced in the seven years since the 2011 ICRP. He noted that Björn (Golder) had discussed the objective-based plan and that he had come to the workshop looking forward to learning Dominion’s objectives but did not believe he had received any of the information at the workshop. Emery asked about thoughts on the framework of the ICRP that will be put forward in July. Eric (EDenholm) noted that there would be additional detail provided in Day 2 of the workshop, specific to closure of the waste rock storage areas (WRSAs), and that part of the intent of the workshop was to get input on the methods and approaches that would be more fulsomely presented in July.

• Emery (IEMA) noted that discussions about caribou and waste rock were forthcoming. He stated that it was difficult to discuss specific topics without knowing the framework the topics were being discussed in. April (Dominion) noted that Dominion requested an 18-month timeline to prepare the ICRP and had





been granted 12 months. April noted that the purpose of the meeting is to gather feedback in advance of the submission deadline and that items that have not discussed will be able to go through the WLWB comment response process.

• Emery (IEMA) acknowledged that the IEMA had previously advocated for shorter turnaround times. He asked what the next steps were for developing the ICRP and any additional input that may be required between the workshop and submission of the 2018 ICRP. Kristine (Golder) requested that this question be deferred until end of day and Emery agreed.

Site-Wide Caribou Engagement

• The 2011 ICRP took a consistent approach across all mine components (i.e., all waste rock piles would be reclaimed in the same manner).

• The refined approach is to consider site-wide caribou movement and how mine components fit on the bigger landscape (e.g., wildlife access ramps were proposed for all waste rock areas in the 2011 ICRP, whereas the 2018 ICRP will consider safety and likelihood of caribou accessing certain waste rock areas).

• Potential risk factors (e.g., injury, mortality, barriers to movement) at a local and regional scale were considered in the 2011 ICRP and will be carried forward to the 2018 ICRP.

• Christine (ERM) gave an overview of the landscape at the mine and noted that there could be opportunities to leave certain features (e.g., roads) in place to facilitate caribou movement.

• Resources of importance at the landscape and regional level will be identified and prioritized based on areas that have high value for caribou and would facilitate safe caribou movement.

• Four questions were developed for break-out session discussion: o What features of the landscape are importance for caribou health and safety, and where do

these features exist at the Ekati mine site? o Based on the landscape and your knowledge of caribou, how would you expect them to

move through the Ekati mine area? o In closure, would caribou use roads to travel between important features similar to an esker? o Is it safer for caribou to allow or prevent access to the waste rock piles?

• Bill (IEMA) noted that the 2011 ICRP planned to put wildlife access ramps on all waste rock piles. He asked if there was potential that Dominion was seeking to do or commit to less reclamation work than proposed in the 2011 ICRP. Harry (Dominion) indicated that the 2011 ICRP approach was uniform across the site, and the objective of the questions was to mitigate risks to caribou safety across the whole site.

• Discussion in break-out groups ensued, after which the following summaries were provided by representatives from each of the break-out groups, as identified below: o Emery (IEMA) noted that caribou will use any flat linear surface, including roads, and that escape

routes or other predator deterrents would need to be installed. He also noted that concerns related to dust generated by roads left in place would need to be addressed. His group also discussed waste rock piles and indicated that there should be some means provided for caribou to move around the piles.

o Joseph (Tłįchǫ Government) noted that his group also discussed dust and waste rock piles. He indicated that there were concerns about caribou not using ramps while being chased by predators due to the ramps not being wide enough. Joseph noted that the caribou is important to the Tłįchǫ people and that site-wide caribou habitat has been a part of the Tłįchǫ TK work.

o Marc (IEMA) noted that caribou tend to use high ground for safety and that promoting safe passage over waste rock is key. He also agreed that the roads would be useful for swift travel but that access points and predation were concerns. The group also identified a concern with caribou drinking runoff water from the waste rock piles.

o Ray (LKDFN) indicated that his group agreed with the previous groups. He also noted that the caribou will not travel under power lines and that the power line along Misery Road would need to be removed even if the road were left in place.

o Ray (LKDFN) stated that he felt that an environmental catastrophe for caribou has occurred and that the caribou decline has affected communities, including Lutsel K’e. Ray indicated that he thought that Ekati and other mines should spend money on research because he felt that it will not be a small problem.

o Ray (LKDFN) stated that there would be more trust in the environmental monitoring at the mines if more people from the communities were involved in the environmental monitoring.

o Ray (LKDFN) noted that a member of the TK working group said that Ekati should be observing caribou prior to coming through the Ekati mine site and any effects after leaving (e.g., limping).

o Ray (LKDFN) indicated his group agreed that caribou would use the waste rock piles and that the rock piles will need to be well capped to ensure that caribou do not risk bioaccumulation by ingesting contaminated vegetation.

o Joseph (Tłįchǫ Government) noted that the Tłįchǫ Elders should be involved in the reclamation planning because they hunted in the areas and will know what the pre-disturbance landscape looked like.





Site Wide Caribou Breakout Session

At the end of the ‘Site Wide Approach to Caribou Movement’ presentation on February 27, 2018, workshop participants were presented with a series of questions and asked to break into three groups consisting of 4-5 people per group to discuss the questions. Specifically, participants were asked to respond to the following:

1a. What features of the landscape are important for caribou health and safety?

1b. Where do these features exist in the Ekati mine area?

2. Based on the landscape and your knowledge of caribou, how would you expect them to move through the Ekati mine area?

3. In closure, would caribou use roads to travel between important features, similar to an esker?

4. Is it safer for caribou to allow or prevent access to the waste rock piles?

Feedback and discussions were recorded per group on flip chart paper and printed maps. At the end of the group break out session, main conclusions were communicated to the larger audience by one to two spoke-persons per group. The main conclusions were summarized by workshop attendees from Dominion Diamond, Golder, and ERM.

Results (Written): The following responses were recorded per group on flip chart paper during the break out session. Responses were organized by question number. Digitized copies of the notes are provided (see Appendix 1). Two of three groups (Group 1 and Group 3) also recorded spatial information on the printed map provided. Spatial information was compiled (Figure 1) and has also been provided as a digitized copy (See Appendix 1).

Group 1:

1a. What features of the landscape are important for caribou health and safety? • Smooth (not rocky surfaces) • Gradual slopes • Decreased ability for predation especially in white-outs • Access to fish (i.e. Narrows) • Decreased insects due to wind • Noise avoidance • Low dust levels

1b. Where do these features exist in the Ekati mine area? • Eskers • Feeding grounds • Muskey • Narrows • Islands

2. Based on the landscape and your knowledge of caribou, how would you expect them to move through the Ekati mine area? • Along roads, along eskers (Figure 1)

3. In closure, would caribou use roads to travel between important features, similar to an esker? • Yes

o Smooth to encourage travel o Gradual slopes on either side o Revegetate o Dust control

4. Is it safer for caribou to allow or prevent access to the waste rock piles? • Slope sides of pile • Possibility to decrease height? • Multiple access points to toe • Caribou will climb to escape bugs • Will caribou use/find ramp? • Test Beartooth/Panda/Koala WRSA for ramp use/option





Group 2:

1a & b. What features of the landscape are important for caribou health and safety? Where do these features exist in the Ekati mine area?

• Forage (quality/quantity) • Low topography (WRSAs are high) • No holes • Natural routes • Safe for walking (hooves) • Man-made areas are safe (because no hunting, less predators) • Caribou know no boundaries (only around lakes) • Shade is good (rest from heat)

2 & 3. Based on the landscape and your knowledge of caribou, how would you expect them to move through the Ekati mine area? In closure, would caribou use roads to travel between important features, similar to an esker?

• Roads, need safe ways for caribou to exit the road – at any time. Site-visit with TK holders is needed.

4. Is it safer for caribou to allow or prevent access to the waste rock piles? • Promoting safe passage over WRSA is key

o need to get on and off (min = 2) • Caribou go in the hills • There are already natural land features that are inapproachable • Consider runoff and erosion for ramp design

Group 3:

1a. What features of the landscape are important for caribou health and safety? • Caribou stick to eskers • Avoid boulder fields

o never see caribou go through boulders/rocks • Migration routes determine the Route

o caribou use landscape to protect their calves • Water keeps them clean and healthy • Esker is important feature • Line of sight and having open areas

1b. Where do these features exist in the Ekati mine area? • Power line - they probably won’t use the area now. If there is no traffic, road will get used

2. Based on the landscape and your knowledge of caribou, how would you expect them to move through the Ekati mine area? • It’s hard to say, maybe they will come back. The water is really important, more monitoring/updates will

give us a better idea if they will come back or they may go in a different direction.

Other notes: • Would like updates to the communities • People from communities working for monitoring to participate in environmental monitoring • Since 1980s, travel towards mine site used to be lots of caribou. There are not many anymore. • Asked to follow caribou outside to see if they are limping but it never happened (to see the caribou

coming to the mine site not limping, leaving mine site to see if they are limping) • See figure 1

3. In closure, would caribou use roads to travel between important features, similar to an esker? • It would be safer for caribou to use the road as an esker • Misery Road, leave it as it is. Keep caribou from boulders, leave it as it is.

4. Is it safer for caribou to allow or prevent access to the waste rock piles? • Caribou would like to go up there to stay away from insects. • Caribou will go up there if it’s really smooth.





Results (Oral) The following main conclusions were summarized orally by one to two group members, and recorded by ERM. Group 1:

• Caribou will use any linear feature (i.e., roads, like eskers) • Predators are a risk, need to be escape routes

o Need more caribou ramps • Wind-blown dust needs to be suppressed • Winter white-outs limit view • Caribou use WRSA especially in areas where caribou go, based on:

o Access o Insect relief o Travel route

• Whole road (from Sable to Misery) likely to be used • Access ramps, should be 1 km long with small rock grain

o Chase/escape from predators is a consideration • Consider the potential for caribou to swim across lakes for movement corridors • More input from Elders is required

Group 2: • Caribou will use high ground (including esker and WRSA) that provides:

o Safety o Relief from insects

• Access and egress is important • Roads would be used by caribou for travel

o Access points are important o Need to be provided places for caribou to get off road

• Traditional Knowledge in important; need to have a site visit to see the landscape • Caribou ingestion of seepage from the WRSA is a risk

Group 3: • Important features include:

o Habitat (food) o Avoidance of boulders o Following eskers

• Previous migration routes are no longer used • Boulder areas afford protection to calves • Use of roads

o Leave Misery Road to function as an esker, but remove the power line • Uncertainty as to whether caribou will come back to the area post-closure • There is a need for caribou research • Participants would like to see things on the land • TKEG group has interest in observing caribou before and after they come through the site to observe

for limping • WRSA would be used by caribou, there must be egress route

Additional Notes The following notes were recorded by Dominion Diamond/Golder/ERM workshop attendees during the break out session. The notes highlighted points that were discussed by groups during the break-out sessions but not captured by within the written responses provided by the groups. 1a. What features of the landscape are important for caribou health and safety?

• Considering of rainfall for caribou safety 2. Based on the landscape and your knowledge of caribou, how would you expect them to move through the

Ekati mine area? • Movement:

o Around lakes only o Movement up and down generally

4. Is it safer for caribou to allow or prevent access to the waste rock piles? • Caribou will eat food impacted by the seepage water from the WRSA • Incorporation of topsoil:

o Incorporation of topsoil to facilitate vegetation growth and opportunities for forage by caribou





Traditional Knowledge

• Luke (Dominion) gave an overview of TK related to the ICRP. Luke noted that TK is an important part of the closure plan; incorporation of TK at the Ekati mine is directed by the Traditional Knowledge Framework. TK is provided through the Traditional Knowledge Elders Group (TKEG), community site visits, and topic workshops.

• Two TKEG presentations focused on the ICRP in 2017, to provide elders with an overview of the approved ICRP and facilitate discussion on specific topics including open pit lakes reclamation, Long Lake Containment Facility reclamation research, site-wide caribou movement, and lakebed sediments.

• The TKEG kicked off in 2017 by having Kugluktuk Elders come to the site.

Next Steps, Wrap-Up & Closing Comments

• Kristine (Golder) confirmed to Emery (IEMA) that the 2018 ICRP will be submitted 6 July 2018, which is 365 days (12 months) after approval of the Jay Project. The full WLWB review process will be determined by the WLWB and finalized closer to or after submission of the 2018 ICRP.

• Emery (IEMA) noted that IEMA would be open to sitting down with Dominion prior to submission of the 2018 ICRP to discuss the contents. April (Dominion) thanked Emery for the offer and noted that the submission deadline is tight.

• Phoebe (Tłįchǫ Government) asked if a draft would be provided to stakeholders to read, review, and comment on. April (Dominion) noted that Dominion was given 12 months to complete and submit the 2018 ICRP and had originally requested 18 months in order to facilitate engagement. She noted that Dominion does plan to engage with communities closer to the submission date to discuss the 2018 ICRP. Comments on the 2018 ICRP would happen through the WLWB’s official comment response process.

• Marc (IEMA) asked if there would be another workshop after submission of the 2018 ICRP. Meghan (WLWB) noted that there is not a clear path forward at this time but that Diavik also recently underwent a review of their ICRP and that the process will likely be similar.

• Kristine (Golder) thanked everyone for their input and April (Dominion) reiterated her appreciation for the group’s input.




Appendix

Break out Session Written Responses




Group 1:







Group 2:




Group 3:







Day Two Items for Discussion

Opening Comments • Welcome and health and safety items. • Introductions. • Joseph (Tłįchǫ) noted that the introductions went around the table counter to the direction of the

sun and suggested in future meetings the order be reversed. Kristine (Golder) thanked him for the feedback.

• A request was made to begin the meeting with a prayer. An opening prayer was provided by August (LKDFN).

Operational Status of WRSAs and ICRP WRSA Closure Objectives

• Luke (Dominion) gave an overview of the location of the WRSAs at the Ekati mine site. WRSA and waste rock management is guided by the Waste Rock and Ore Storage Management Plan.

• Waste rock placement is part of the Water Licence requirements for the site. The WLWB approval addresses:

o WRSA geochemical characteristics o WRSA design principles o WRSA operating plans o WRSA monitoring and adaptive management

• Approximately 50% of the samples of the metasediment rock type are non-potentially acid generating (non-PAG); nonetheless, all of the metasediment rock type is managed as if it were potentially acid generating (PAG).

• Luke (Dominion) gave an overview of the existing and planned WRSAs at the Ekati mine site and their composition (e.g., overburden, granite).

• An annual seepage report is prepared to: o report the outcome of field crew investigations into potential seepage from WRSAs o describe WRSA construction rock geochemistry o provide WRSA thermal information

• WRSAs are evaluated from a risk-based approach and that approach will inform the objectives (e.g., seepage water quality).

• WRSAs are designed and constructed with the following considerations: o seepage water quality o environmental interactions with surface material (e.g., wind, erosion) o stability o separation of inert waste from the environment o wildlife safety

• Peter (Hamlet of Kugluktuk) asked if Dominion had discovered any uranium during exploration. April (Dominion) said that uranium had not been encountered but that uranium concentrations were monitored as part of the seepage monitoring. An increase in uranium concentrations at the Ekati site has not been observed.

• Emery (IEMA) asked about the concept of effective neutralizing potential, introduced on Slide 8, and asked if the slide showed the result of view testing using full neutralization potential. Kristin (Golder) confirmed that his interpretation of the slide was correct and that the existing geochemistry data set will be re-evaluated in the context of the effective neutralization potential.

• Wilfred (FRMC) asked about building dikes or berms around WRSAs to prevent runoff or seepage from affecting the larger watershed. He also noted that the WRSAs were too high for caribou to use. Luke (Dominion) noted that the watershed is an important consideration of closure design and thanked Wilfred for his follow up comment on the heights of the WRSAs.

• Wilfred (FRMC) reiterated his statement about dikes/berms and the WRSA heights in relation to caribou. April (Dominion) thanked him and noted that there had been discussion about the WRSA heights and caribou on Day One of the workshop. She confirmed that there would be follow-up engagement with the communities on the ICRP.

• Stanley (DKFN) asked how long the WRSAs would be frozen. Luke (Dominion) stated that Dominion’s models indicate that the WRSAs will completely freeze through within 100 years of placement with seasonal melt and freeze on the surface.

• Joseph (Tłįchǫ Government) noted that the Tłįchǫ Elders have not studied rocks or geochemistry and requested that the WRSA information be presented in plain language format. He reiterated that it was important to not contaminate the barrenlands and requested that this feedback be included in the 2018 ICRP. He asked if stockpiling overburden was safe for the wildlife and stated that the Aboriginal people living on the land rely on wildlife and there is concern over contamination or destruction of habitat. He proposed that the WRSAs could be tarped off. Joseph also requested that an esker at the Jay pipe not be altered or destroyed because it is used by wildlife and for hunting. He noted that the stockpile data for the WRSAs do not make it immediately clear what formations will be affected and where. He noted that it was important to minimize changes to the land and for wildlife to continue using the habitat. April (Dominion) thanked Joseph for his comments, noted a recent IEMA waste rock workshop, and agreed that it





would be useful to continue such workshops. April noted that the road to Jay does cut through the esker and that material had been stockpiled to rebuild the esker at closure. April thanked Joseph for his comment on caribou safety and noted it had also been discussed during Day One of the workshop. She stated that community engagement would extend into the spring and would include community elders. She also thanked Joseph for his statements on the difficulty of interpreting numbers (i.e., stockpiles). April noted that Dominion is open to arranging site visits and ongoing community engagement.

• Phoebe (Tłįchǫ Government) stated concern about waste rock piles at Fox Pit and noted that when the Snap Lake Mine shut down, there was no reclamation or closure plan for the rock pile at Snap Lake. She noted that culverts under rock piles could contribute to seepage and that there is currently seepage from unfrozen piles and as noted earlier, it is expected to take ~100 years to freeze. Phoebe asked about the potential for seepage to affect the surrounding watershed, the aquatic and terrestrial wildlife, and ultimately humans who ingest the wildlife. Luke (Dominion) noted that not all the piles are currently frozen. He stated that seepage from the waste piles had to be good quality and have no impact on the land and that Dominion’s responsibility is to demonstrate that there are no impacts during operation or after closure.

• Ray (LKDFN) asked about mitigation measures to prevent water/metasediment seepage. Luke (Dominion) noted that metasediment was part of the neutralization potential evaluation.

• Ray (LKDFN) asked if the WRSAs would be exposed or capped with material. Luke (Dominion) noted that capping was part of the discussion in the workshop and that capping would depend on overall evaluation of material types.

• Marc (IEMA) questioned the models showing that the WRSAs would freeze within 100 years and noted that IEMA has previously submitted comments questioning the model. He asked if there would be an opportunity to discuss the models. Luke (Dominion) stated that the opportunity would occur shortly.

• Marc (IEMA) also noted that the effective neutralization potential ratio was important because it indicates how much rock could potentially be of concern. He asked how the neutralization potential was characterized in the model. April (Dominion) asked about the comments submitted and Marc noted he had brought the comments to the meeting.

• Marc (IEMA) summarized the comment and noted that future acid rock drainage (ARD) predictions should use the suggested correction of subtracting 10 kg per ton from measure neutralization potential. April (Dominion) noted that the previous comments on neutralization potential indicated that the work was ongoing and that this is something that Dominion may look at in the future.

• Emery (IEMA) asked if effective neutralization potential or the 10 kg per ton modifier will be used and how will historical data sets be adjusted. Luke (Dominion) noted that the WLWB provides direction and guidance on the seepage report, which neutralization potential is a part of. He noted that Dominion may not be able to provide a commitment to either effective or modified neutralization potential during the course of the workshop.

• Bill (IEMA) noted that Dominion is seeking to provide updated closure objectives for waste rock. He noted that there is risk that developing a closure plan based on objectives may not give Dominion an idea of people’s/community views. He also noted that during Day One of the workshop, it was stated that the goal is to return the Ekati mine site to viable and where practicable self-sustaining ecosystems that are compatible with a healthy environment, human activities, and surrounding environment. Bill did not see a link between the WRSA objectives and the goal (i.e., nothing directly related to viable or self-sustaining ecosystems).

• Bill (IEMA) noted that one of the objectives was to build the WRSAs as designed. He noted other mines and mine components that had been built as designed and had failed—he stated that building to design did not necessarily define success. Luke (Dominion) thanked Bill for his input and noted that not all of the comments would be addressed right away due to schedule. He agreed that all components of the ICRP need to fit together.

• Patty (WLWB) asked if the objectives of the 2018 ICRP were going to change from the objectives in the approved ICRP and, if so, if it would be communicated prior to submission of the 2018 ICRP in July 2018. April (Dominion) noted that the timeline had been discussed on Day One of the workshop. She noted that feedback and concerns from the workshop would be incorporated into the planning process and that the 2018 ICRP will be an update to the existing and approved ICRP, which presents objectives.

• August (LKDFN) asked if any samples have been taken from the base of the WRSAs (e.g., moss samples). April (Dominion) stated that lichen is sampled through air quality monitoring every three years, that a lichen sampling program had been completed in the summer of 2017, and that results of the program would be available by the end of Q1 2018. April noted that feedback indicates that Dominion could be better at communicating results of programs to communities.





• August (LKDFN) noted that three years was a long time between sampling and that precipitation interacted with the WRSAs each year. April (Dominion) thanked August for the comment.

• Ray (LKDFN) noted that the lichen sampling is an air quality monitoring program and he did not think it addresses water seepage into the ground. He asked about different methods for sampling seepage water, including sampling from holes dug around the WRSAs. April (Dominion) stated that seepage monitoring takes place in addition to lichen monitoring and suggested talking about the programs during lunch (i.e., off the record).

Information and Commitments for WRSA Closure Planning and Updated WRSA Reclamation Studies

• Eric (EDenholm) gave an overview of the waste rock storage area risk assessment framework (WRAF). The WRAF is a Dominion-initiated project that builds on reclamation research and field investigations to develop a means of better understanding and discussing the long-term risks associates with WRSAs.

• Eric (EDenholm) provided an overview of research studies carried out after submission of the 2011 ICRP and noted reclamation research programs (RRPs) 31, 32, 33, and 78, which were specifically directed at WRSAs and noted the ongoing monitoring of WRSAs.

• WRAF model components: o thermal prediction model o water balance model o seepage quality prediction model o ecological risk assessment model

• The primary components integrated to build the WRAF were: o findings of Reclamation Research Studies o WRAF models o operational monitoring results, research studies, and field investigations o engagement results

• Eric (EDenholm) noted that there are eight topics that Dominion has compiled for future research projects, representing Dominion’s commitments and lessons learned:

o climate change o WRSAs / acid rock drainage metal leaching (ARD/ML) o WRSA active layer depth o WRSA internal freezing o WRSA water balances o WRSA monitoring and evaluation o WRSA seepage flow patterns o closure seepage water quality criteria

• Peter (Hamlet of Kugluktuk) noted that climate change is one of the biggest events happening in the Northwest Territories and asked if Dominion had noticed the permafrost melting around the Ekati mine site. Gary (TetraTech) stated that the permafrost depth has not changed much over the past 15 to 20 years of monitoring. He noted that climate change is considered in the prediction modelling.

• Wilfred (FRMC) requested that Dominion focus studies on the watershed and that he did not feel that the communities were getting answers on specific risks to the watershed. He stated concerns with potential for bioaccumulation in the environment. Luke (Dominion) stated that he acknowledged the importance of the watershed and that the best strategy would be to take the comments from Wilfred and Joseph and address the concerns in future engagement. April (Dominion) noted that placement within the watershed(s) is a concern when designing the WRSAs and that seepage and monitoring is ongoing after placement.

• Peter (Hamlet of Kugluktuk) noted that permafrost is melting elsewhere and asked about Dominion’s control of permafrost melting. Luke (Dominion) noted that part of the strategy in building the WRSAs was to help the permafrost move up the piles through strategic materials placement.

• Bobby (Hamlet of Kugluktuk) asked about stockpiling methods to reduce dust emissions. Luke (Dominion) stated that wind direction is an important consideration for snow accumulation and affects the rate of freezing for the pile

• Bobby (Hamlet of Kugluktuk) stated concerns about contaminants in dust affecting grazing caribou. April (Dominion) thanked Bobby for his statement and said that it would be considered; she noted that there is not a lot of dust associated with the WRSAs.

• Bill (GNWT, ENR) asked if the timelines proposed for the WRSA seepage flow pattern and water criteria research programs were adequate (two years). Eric (EDenholm) clarified that it was proposed to undertake the research programs within the first two years after approval.

• Bill (GNWT, ENR) asked if there were any threshold triggers that would result in seepage monitoring to take place on more than a twice annual frequency. Luke (Dominion) noted that a change to frequency would be part of adaptive management and that the adaptive management





actions, triggers, and criteria were currently under review. He noted that installation of equipment that could monitor over a season could be considered.

• Ray (LKDFN) asked about shallow groundwater monitoring by drilling to the top of the permafrost list in order to obtain subsurface flow samples from drainage at the centre of the WRSA. Eric (EDenholm) stated that if there is an indication of subsurface flow during seepage monitoring, samples would be taken. Eric noted that the WRSAs tend to be in glacial till or directly in rock which would not direct water through the materials.

• Wilfred (FRMC) asked about freezing the spaces between rocks in the WRSAs and stated concerns about using chemical treatment to aid freezing of the WRSAs. Eric (EDenholm) stated that no freezing agents are in use. Mike P (Golder) noted that the water contained within the WRSAs freezes, and therefore, fine-grained material will freeze together while coarser material (i.e., boulders with noticeable gaps between them) may not.

• Wilfred (FRMC) stated that he felt it was important to study the depth of permafrost and suggested this could be done through the drilling proposed by Ray (LKDFN). Luke (Dominion) demonstrated the monitoring system employed at the Koala WRSA showed that the pile above the ground level as internally frozen, and so flows were predominantly at the surface of the WRSA.

• Marc (IEMA) noted that perhaps the questions were less about seepage and more about water balance and where runoff and surface flows go during high flow events (e.g., freshet). Marc noted that this has been a comment on the 2016 Annual Seepage Report from IEMA. Marc asked if the WRSA seepage flow patterns RRP would evaluate surface flows or surface and subsurface flows. Luke (Dominion) noted that in the permafrost regime presented, permafrost acts as a barrier to flow. Mike P (Golder) noted that the conceptual model has flow from the middle of the pile out to the toes of the WRSAs and that flow has been accounted for in the water balance model.

• Marc (IEMA) asked about installing instrumentation to monitor subsurface flows and take water samples. Mike P (Golder) thanked Marc for the suggestion and noted it would be taken into consideration.

• Wilfred (FRMC) stated disagreement with the placement of rock layers, noting that they would dry up/break up in the summer. Mike P (Golder) agreed and noted that the freeze/thaw cycle has been taken into consideration.

• Phoebe (Tłįchǫ Government) noted that the Fox WRSA is not freezing and some areas are eroding. Phoebe noted that similar work at Misery showed mitigation measures related to stockpiling PAG materials, non-PAG materials and drilling direction/activities but did not see the same mitigation measures at Fox. Phoebe asked if there are any visuals to show the interior of the Fox WRSA or reports on WRSAs that are in non-frozen condition. Luke (Dominion) noted that studies were completed in 2015 and the reports were provided at the time and remain available. Luke noted that there are operational mitigation measures in place to limit impacts of seepage from non-frozen WRSAs. Gary (TetraTech) stated that the more moisture is in a WRSA, the longer it takes to freeze. The modelling conducted for the Fox WRSA indicate that it will freeze but could take ~40 years. Gary stated that WRSAs in operational areas are also not expected to freeze completely due to new material being added.

• Phoebe (Tłįchǫ Government) stated dissatisfaction with the amount of time the WRSAs will take to freeze. She noted that Las de Gras flows into the Coppermine River, which flows to Kugluktuk. Phoebe requested additional engagement including technical workshops and meetings. April (Dominion) thanked Phoebe for her input, noted the purpose of the workshop was to elicit feedback and concerns from communities. April noted that some concerns may be addressed through the existing Ekati mine monitoring programs.

• Bobby (Hamlet of Kugluktuk) noted that he has seen a decline in the number of fish caught during the fall at Kugluktuk. He stated concerns related to contamination and to the water warming. He suggested that part of the closure plan could involve marshes or other similar ecosystems to filter potential contaminants coming off the WRSAs before they enter the watershed. April (Dominion) thanked Bobby for his comment and noted that Dominion currently engages in substantial water quality and runoff monitoring. April also noted that she was looking forward to the community-based water quality monitoring project developed during the approval process for the Jay project.

• Shawn (FRMC) asked if Dominion had baseline groundwater quality information for each location of the WRSAs. April (Dominion) confirmed that there is baseline information for surface water, shallow groundwater and deep groundwater at the Jay and Panda/Koala sites.

• Shawn (FRMC) noted that contamination could occur within the groundwater column rather than in the runoff at the toes of the WRSAs. April (Dominion) thanked Shawn for his comment and noted it would be considered during development of the 2018 ICRP.

• Ray (IEMA) noted that there was no research directed toward the recovery of the Bathurst caribou herd, although an upcoming study correlated the decline of the herd with the diamond





industry. April (Dominion) thanked Ray for his comment and noted that Dominion has committed to caribou research as part of the Jay permitting process.

• Emery (IEMA) suggested that the WRSA seepage flow patterns report could consider shallow subsurface flow patterns in addition to surface flows. Emery asked about the plans for the 2018 seepage flow monitoring. Luke (Dominion) noted that flow monitoring is incorporated into the annual seepage monitoring and that the purpose of the 2018 seepage monitoring is to provide a stronger understanding of the seasonal aspects of flow.

• Emery (IEMA) asked if the 2018 monitoring would be surface flow monitoring. Luke (Dominion) said yes.

Pigeon WRSA Management Approach and Closure Cover Design

• Annie (Dominion) provided an overview of the Pigeon WRSA. The rock at the WRSA consists of interbanded granite with metasediment that cannot be separated prior to deposit in the WRSA.

• Kristin (Golder) gave an overview of neutralization potential (i.e., a measure of available carbonate or other minerals that can be used to neutralize acidity from the oxidation of minerals).

• The materials in the Pigeon Pit are geologically unique compared to other materials found on the Ekati mine site but sampling to date does not show greater acid general potential than other Ekati sites.

• The next step is to evaluate if the results of the neutralization potential study carry forward to operational conditions.

• Gary (Tetra Tech) gave an overview of the thermal performance and stability analysis of the Pigeon WRSA closure cover design.

• The closure cover of the Pigeon WRSA has changed from 3 m of till covered by 1 m granite to 2.4 m of till covered by 1.8 m of granite, due to an increased pile size at the Pigeon WRSA.

• Emery (IEMA) asked if the Pigeon WRSA closure design would be provided to the WLWB for approval. April (Dominion) stated that the closure cover for Pigeon WRSA is not yet approved and the WLWB will need to make a decision on the closure plan.

• Gary (TetraTech) gave an overview of the proposed design of the Pigeon WRSA and the thermal and climate change considerations than went into the design. A sensitivity analysis of effects of heat generation due to pyrite oxidation was carried out in support of the design.

• Paul (GNWT, ENR) asked if the till will be placed in the Pigeon WRSA and then the rocks or will they be co-placed. Gary (TetraTech) responded that the likely approach will be co-placement.

• Kevin (IEMA) discussed neutralization potential and noted that the presentation appeared to imply that if a sample has enough neutralization potential, no acid water will be released. He noted that work at the Ekati mine in 1995 and 1996 indicated that a neutralization potential of less than 10 would be acid generating and that nearly half of the samples had a neutralization potential of less than 10. He noted that sample PDL 10 on Slide 67 had a neutralization potential of 2.6, but the sample turned acid in approximately six months and there is potential for there to be more acid-generating waste material at Ekati than previously anticipated. He noted that the heat generated from oxidation is a concern in relation to the assumption that the WRSAs will freeze. Kevin (IEMA) stated a concern with the plan to layer net acid generating and net neutralizing rock at the Jay Project and the existing plan at the Misery site. Kristin (Golder) acknowledged the 1995 and 1996 Ekati work and stated that additional work has been done since preparation of the reports, and that further work would be done. She noted that the value of PDL 10 is higher than 2 (2.6) and that the sample has one of the greatest total sulphur contents in the data set. The granite at the Ekati site has an overall low sulphur content of ~0.02% with low acid generation potential. WRSAs at Panda and Koala remain frozen and there is confidence that in site-specific conditions, the material will not react. Kristin (Golder) noted that there is confidence in the conditions on and around the WRSAs due to ongoing monitoring and modelling.

• Kevin (IEMA) expressed concerns that the Mine Environment Neutral Drainage (MEND) ARD prediction manual has not been adhered to at the Ekati mine site. Kristin (Golder) gave additional context about the neutralization potential/acid potential (NP/AP) ratios selected for the project and indicated that the average NP/AP ratio was 13. The next steps include consideration of effective neutralization potential and previously collected data and reports will be reviewed. April (Dominion) stated that Ekati was exceeding best practices in terms of management of waste rock.

• Kevin (IEMA) reiterated that Ekati was not compliant with the MEND prediction model, not with management of ARD materials. There is no uncertain category with the MEND model. He stated that per his understanding, Ekati will soon be in compliance with the MEND prediction manual (not the management manual). April (Dominion) noted that the approach to any uncertain materials is to proactively treat them as PAG.

• Kevin (IEMA) stated that a sulphur content of 0.02% is high and that humidity cells with sulphur levels of 0.03% have turned acid. He noted that 0.02% of several million tonnes of waste rock is a substantial amount of material with potential acid generation. Kristin (Golder) stated that





humidity test cells of samples from Ekati show sufficient neutralization potential to address 0.02% sulphur content. The data set shows that material with low (0.02%) sulphur do not generate acidity in the long term. Additional factors (e.g., thermal modelling) address other opportunities for PAG beyond humidity cell tests of samples.

Next Steps, Wrap Up & Closing Comments

• Wilfred (FRMC) restated his concern with the use of hazardous materials at the site and potential for bioaccumulation in wildlife. He noted some positive results of the Ekati mine, including IBAs (Impact Benefit Agreements) and access to winter roads. April (Dominion) thanked Wilfred and noted that Dominion will be sharing results of monitoring programs with the communities.

• Ray (LKDFN) asked about response planning for potential environmental accidents or undesirable outcomes (e.g., seepage). Luke (Dominion) confirmed that the Ekati mine site employs an adaptive management strategy that would be used to drive response to any type of unexpected event or outcome. A section of the ICRP will discuss contingency planning based on predictions for the future.

• Monica (KIA) noted concerns with contamination from local sources and also from global sources (e.g., deposition from Chinese industry). She noted that animals do not have boundaries or protections from all potential contamination sources. She expressed gratitude for the opportunity to take part in the workshop. April (Dominion) expressed her gratitude for all attendees who travelled to the workshop.

• Emery (IEMA) noted that objectives of the workshop included discussing and further advancing the ICRP and he felt that objective was successful. He noted another objective was to discuss or address outstanding concerns raised by parties (e.g., waste rock storage, seepage). He noted that he did not expect consensus on the topics but he did appreciate the opportunity for open and respectful communication. He stated that he felt that Dominion was hearing the concerns that were being raised. He expressed interest in the thermal modelling, which he did not have previous awareness of.

• Emery (IEMA) expressed appreciation for the workshop and wanted to ensure that it was clear that IEMA was open to further discussion. April (Dominion) expressed gratitude for Emery’s thoughts.

• Stanley (DKFN) asked if Ekati has established action levels for the WRSAs. Luke (Dominion) stated that the annual seepage reports use a screening mechanism that has been an adaptation of criteria for other mine components. Dominion is looking to optimize and evolve the criteria to make them more appropriate for the WRSAs.

• Marc (IEMA) asked if the total discharge numbers represented in the water balance were in reference to water leaving (i.e., runoff) or if it included wetted up (i.e., water drawn down into soils) numbers. Mike P (Golder) stated that discharge is the total volume of water coming out of the waste rock pile and does not differentiate between surface or subsurface discharge.

• Marc (IEMA) asked how much flow is measured during sampling versus total discharge at the Panda Pit and the ratio between the two. April (Dominion) suggested that she would follow up with Marc via email.

• Kristine (Golder) and Luke (Dominion) thanked the attendees for their participation. Luke stated that the information gained though the workshop would be used to facilitate future engagement and mine planning, including the 2018 ICRP.

• A closing prayer was completed by August (LKDFN) and the meeting was adjourned.




Commitment Summary Topic Commitment

Reclamation Dominion will consider a reclamation completion report for the Old Camp reclamation. This report may be tied to the reclamation security deposit for site components.

Engagement Dominion will engage with communities on the 2018 ICRP prior to submission of the document in July 2018.

Engagement Community engagement will extend into Q2 2018 and will include engagement with elders.

Engagement Dominion will consider community concerns related to potential water quality changes in the watershed, and provide additional information to communities related to ongoing monitoring programs.

Monitoring Dominion will follow up with Marc (IEMA) on the flow measured during sampling versus the total discharge at Panda Pit.

Monitoring Dominion will consider subsurface flows and groundwater in the WRSA monitoring program.

Monitoring Dominion will continue to optimize and evolve the criteria for seepage action levels to make them more appropriate for the WRSAs.

https://golderassociates.sharepoint.com/sites/12103e/ddecekatiicrpntexternal/04_icrp/appendices/appendix_c - record of engagement/01_dominion_ekati icrp_meetingnotes.docx





ICRP Ver 3.0 Community Site Visit Engagement

Interim Closure and Reclamation Plan (ICRP) V 3.0 Update

SECTION TITLEInterim Closure and Reclamation Plan (ICRP)

• Version 2.4 describes the work plan to reclaim the Ekati mine during production and following the end of operations.

• $295 million currently held by the Government in reclamation security for activities outlined in the ICRP.

• ICRP being updated (Version 3.0) for submission to the WLWB in July 2018. Updated Plan will include the Jay project.

Interim Closure and Reclamation Plan (ICRP) V 3.0 Update 1

SECTION TITLEICRP Community Engagement

Gather community information on the development of updated ICRP

2Interim Closure and Reclamation Plan (ICRP) V 3.0 Update

SECTION TITLEOpen Pits Reclamation

• Pump water to fill open pits

• Reconnect water flows via water channels when water quality is safe

• Leave pit ramps in place for exit

• Construct littoral zones in selected pit lakes


SECTION TITLE

4

OPERATIONS (CURRENT)Beartooth Pit

Operations: Panda/Koala/Beartooth Pits


SECTION TITLE

5

OPERATIONS (CURRENT)Koala/Koala North & Panda Pit Beartooth Pit


Reclamation: Panda/Koala/Beartooth Pit Lakes

SECTION TITLEPanda/Koala Pit Lake Cross Sections

Interim Closure and Reclamation Plan (ICRP) V 3.0 Update 6

SECTION TITLEUnderground Reclamation

• Remove all hazardous waste materials and mobile equipment• Flood underground workings • Block access to mine entrances and seal air raises


SECTION TITLE

• Ensure safe water quality

• Ensure physical stability

• Wildlife safety ensured in context of site wildlife movement

8

Waste Rock Storage Area Reclamation


SECTION TITLE

9

Wildlife Safety: Rock Piles


Is it safer for caribou to allow (via access\exit ramps) or prevent access to the waste rock piles?

SECTION TITLEProcessed Kimberlite Containment Areas

• Wind and water erosion of processedkimberlite is controlled by vegetationand rock cover and water channels

• Wildlife safety ensured in context ofsite wide wildlife movement

10

SECTION TITLEVegetation and Rock Cover Research


SECTION TITLESurface Water Channel Research


SECTION TITLEBuildings and Infrastructure & Roads

• Remove hazardous waste material offsite• Ensure hydrocarbon areas are

appropriately remediated• Landfill all inert non hazardous material

from demolition and cover landfill• Surface drainage is channeled through

watersheds• Selectively scarify and vegetate pads,

roads, laydowns and airstrip in the context of wildlife safety and movement


SECTION TITLE

14

Wildlife Safety: Roads


In closure, would caribou use roads to travel between important features, similar to an esker?

SECTION TITLE


Thank You !



Date: 10 April 2018

Community/Group Represented: Yellowknives Dene First Nation

Feed

back

on

Pro

ject

Com

pone

nts

Open pits • Concern expressed about the impact of water withdrawal from lakes on fish • Concern expressed regarding groundwater movement within open pits

Waste rock storage areas

• Comment that caribou are unlikely to travel onto waster rock storage piles as caribou do not like to walk on rock

• Comment that caribou would bypass the piles • Comment that, in the absence of food or mating opportunities, caribou would have no reason to

go on the piles, particularly if there are other animals present • Comment that if caribou feel safe, they may still go on the waste rock storage piles

Processed kimberlite containment areas

• Comment that vegetation research isn’t going to solve the issue of removing waste • Question raised regarding the suitability of animals harvested in these areas for eating • Question regarding repopulating animals at closure in these areas, and comment that animals are

eaten along with plants

Underground reclamation • No questions, comments, concerns

Buildings, infrastructure, and roads

• Recommendation that reclamation activities should be happening now • Comment that caribou will walk on roads, regardless of scarification • Comment that non-biodegradable waste is unsafe for birds and fish • Comment that there is a small window to remove materials from the site • Comment that roads must be safe for caribou, and that fences would keep them out • Concern that future generations will be paying for the cost of closure • Concern that items left behind and buried will cause environmental impacts



Date: 14 May 2018

Community/Group Represented: Fort Resolution Métis Council / Deninu Kue First Nation

Feed

back

on

Pro

ject

Com

pone

nts

Open pits

• Recommendation that actions should be outlined to trigger monitoring • Recommendation that processed kimberlite should be placed on waste rock piles, rather than in

pits. • Recommendation that, in future meetings to discuss the ICRP, the plan should be circulated to the

Métis council so they can prepare ahead of time • Comment that the water used to be pristine, and safe to drink • Comment that saying water is safe isn’t enough to make people feel good • Question as to why Dominion is working through the Wekeezii Land and Water Board? It’s not in

their area, the mine is developing on Akaitcho territory • Comment that our water is under attack; we need to fight to make sure it is brought back to its

original shape • Question if the diversion channel is being tested to ensure the water is clean, pure, and drinkable • Question regarding the source lakes for put flooding • Question regarding water quality criteria • Question regarding the timeline for connecting water flows • Question if kimberlite will settle before the pit flooding begins • Question if processed kimberlite deposition will affect the chemistry of the pit lakes • Concern that the water in pits with PK deposition will mix and become less fresh


• Recommendation that Dominion put a hollow at the base of that rock pile; caribou like to go up to the higher ground, they like the breeze to blow the bugs and mosquitoes off

• Recommendation that caribou not be allowed on the WRSA piles, as there are too many different sized rocks

• Recommendation to clean up any areas that caribou go • Comment that the mine should be reclaimed using Dominion’s money, not the money of the people

of the north • Comment that the closure plan needs to be set in stone • Question about what is being done to allow caribou crossing after Jay • Question if Ekati will be sold again; it has happened before • Concern regarding the distance from the watershed • Concern that chemicals from piles will flow out into the watershed • Concern that caribou could get stuck on top of waste rock piles, and that the piles present the risk

of caribou breaking their legs


• No questions, comments or concerns raised

Underground reclamation • No questions, comments or concerns raised


• Recommendation that road material be used to cover the waste rock • Recommendation to treat the road like an esker, and make ramps so caribou can cross

comfortably, including at major crossing locations • Recommendation to identify caribou crossing areas, and remove those segments of road, returning

the dirt back to where it came from • Comment that you can’t control caribou – they will go on the road whether you like it or not • Comment that caribou hang out on the high banks in the wind, and should have a way down • Concern that roads could lead to areas that are contaminated or dangerous to caribou



Date: 16 May 2018

Community/Group Represented: Independent Environmental Monitoring Agency Attendance: Dominion: Lukas Novy, April Hayward, Lyn Boettger, Nicholas Ballantyne, Keira Nolting IEMA: Marc Casas, Shannon Moore, Emery Paquin, Bill Slater (phone)

Discussion Items

• Design criteria for LLCF Vegetation cover • When and how will the closure criteria be developed • Difference between qualitative and quantitative criteria • Review process submission of ICRP • Relinquishment process for return of security • Update on community engagement visits • Misery WRSA Drilling Investigation • Reclamation Research Plans



Date: 17 May 2018

Community/Group Represented: Lutsel K’e Dene First Nation

Feed

back

on

Pro

ject

Com

pone

nts

Open pits

• Question as to how processed kimberlite in pit lakes will affect fish health • Question regarding the drinkability of water • Question regarding the depth of pit filling • Question regarding the frequency of water quality testing • Concern regarding overall water quality in pits


• Recommendation to slant rock piles to allow caribou access up the sides, and to avoid bugs • Recommendation to use fine rock on the pile sides to prevent injury to caribou feet • Recommendation that smaller rocks be used on the piles to protect caribou, and that large rocks be

covered with fine rocks, dirt, or gravel • Recommendation that testing occur to ensure caribou and fish are health • Recommendation to remove rock piles, and to put waste rock into the pits • Comment that the land should be put back the way it was before Ekati • Comment that rock piles are too large and change the landscape • Concern for caribou safety on the piles, noting that large rocks could break caribou legs


• Comment that community members would like to see vegetation growth in person

Underground reclamation • Concern that processed kimberlite in underground workings could affect ground water


• Recommendation that buildings be removed at closure



Date: 29 May 2018

Community/Group Represented: Whati

Feed

back

on

Pro

ject

Com

pone

nts

Open pits • Recommendation that the open pits, including Fox Pit be filled with rock


• Recommendation that Dominion monitor the site to see if rock piles are safe for animals • Recommendation that rock piles are made smooth all the way around so wildlife can get up easily • Recommendation to find out how big the influence of the mine is and if it is affecting wildlife or not • Recommendation that the waste rock be used to fill the pits from where it came • Recommendation to bring Elders up for a couple days at a time to see what the plan is about • Comment that everything should be put back to way it was • Comment that animals are unable to climb up large boulders • Comment that the waste rock piles are high • Concern that rock piles are hazardous to wildlife • Concern that heavy equipment active on site can be heard by, and affect wildlife


• No questions, comments, concerns raised

Underground reclamation

• Concern that cables and underground wires could negatively affect the water that wildlife will drink • Concern that hazardous materials could be left behind at closure • Concern that, if the underground operation is not covered by rock, it will not be safe to animals and

the land will never be the same


• Recommendation to break up roads and remove segments so caribou will feel more comfortable to cross over, or to pass through

• Comment that caribou have a hard time crossing the roads • Concern that, when Elder groups come to the mine, not much is completed on the roads or with

reclamation



Date: 29 May 2018

Community/Group Represented: North Slave Métis Alliance

Feed

back

on

Pro

ject

Com

pone

nts

Open pits

• Recommendation that water quality monitoring continue until conditions are safe for fish • Comment that, in the area of the Ekati environmental footprint, there should be some areas suitable

for open pits again • Comment that it would be cheaper to have another open pit without having to dyke everything like

Jay • Comment that it will require a lot of water to fill up the pits • Question as to how beach locations (littoral zones) are decided • Question as to whether fish will go back into the pits or not • Question regarding the depth of fresh water cap over PK • Concern regarding pit lake connections with each other and downstream flow


• Recommendation to place finer crush along the sides of the waste rock piles to fill gaps • Recommendation to cover the piles with smaller crushed rock to ensure they are safe for caribou to

go up and down, only going around the piles would be different • Recommendation to prevent access if possible to the piles, as it is not a natural pile of rock that

caribou would be used to • Recommendation to block off the waste rock piles and close the roads • Recommendation to take out a bit of the camp so caribou can go up • Comment that Dominion wants easy access for roads, but that the rock piles are huge • Comment that caribou are going to have to go around the piles • Comment that the ramps could be ripped out, or made steeper • Comment that if caribou want to go up the piles, they will. • Comment that caribou are normally an animal of passage, and so will avoid the piles • Comment that re-sloping the piles would take a lot more material • Question as to whether there will be monitoring or not • Concern that caribou could break their legs going up the sides of the piles with coarse rock • Concern that caribou may get stuck on top of the piles


• Recommendation that there be studies based on what can live in kimberlite

Underground reclamation

• Comment that there is no harm from steel underground • Comment that activity under Panda, Koala, and Koala North pits is coming to an end • Comment that there will be some things that will never come out • Concern regarding entrances to the underground


• Recommendation that the airstrip not be removed as it could save someone’s life • Recommendation that more caribou crossings be installed on the road • Comment that there shouldn’t be a lot of access to the area at closure • Question if caribou are using existing caribou crossings • Concern that if hunters may use the airstrip and over-hunt • Concern that Dominion will remove the airstrip



Date: 4 June 2018

Community/Group Represented: Gameti

Feed

back

on

Pro

ject

Com

pone

nts

Open pits

• Recommendation to not connect filled pit lakes with channels • Comment that it doesn’t make sense to refill the water and channel the lake • Question regarding the water source to fill pit lakes • Concern regarding water quality in pits, and in waterways flowing to Behchoko • Concern that fish and water in the lakes will never be the same as it was


• Recommendation that, if waste rock won’t be put back into the pits, crush should be added to the piles to prevent caribou injury

• Recommendation to take people out to the mine once reclamation is complete • Concern that WRSAs are rough and could injury caribou • Concern regarding large rocks standing out from the berms • Concern regarding the number of waste rock storage piles


• Concern regarding contamination from processed kimberlite • Concern regarding residual processed kimberlite from the Fay Bay spill • Concern regarding climate change

Underground reclamation • Concern that underground water will not be clean, and will go up to communities • Concern regarding the condition of the underground before flooding.


• Recommendation that roads, including specifically the road to Sable, be ripped out at closure



Date: 12 July 2018

Community/Group Represented: Hamlet of Kugluktuk

Feed

back

on

Pro

ject

Com

pone

nts

Open pits

• Question regarding how water is getting into the pits, and where it is coming from • Question regarding how much material will be taken out of the pits, and how much will remain • Question regarding whether the open pits will be filled with water or not, and where overflow water

will go • Question regarding what Dominion will do if caribou do not return to the area of mining • Question regarding the length of time that water will spend in the pits before the channels take it

into the natural environment • Question if Dominion will conduct water monitoring after the mine is closed • Concern that, if material are left behind in the pits, contamination will leech through the permafrost • Concern that animals will not return to areas of open pit mining

Waste rock storage areas • No questions, comments, concerns raised


• Question if there will be hazardous materials in the ground associated with water leeching • Question regarding how long it will take before water is safe to discharge into the environment

Underground reclamation • Question regarding how far down underground operations go • Question regarding fresh aid underground


• Recommendation to cover the large boulders along the sides of the road with smaller rocks • Question regarding what is done with the furniture (beds, chairs, etc.) when infrastructure is taken

down



Date: 17 July 2018

Community Represented: Behchoko Chief and Council Meeting

Feed

back

on

Pro

ject

Com

pone

nts

Open pits • Question regarding the intended depth of the pit lakes • Question if there will be a manual diversion channel • Question if the fish diversion area has begun to populate and flourish

Waste rock storage areas • Comment that a single ramp would create a predator corridor • Comment that caribou naturally seek high ground to expose themselves to wind • Concern that the boulder size will be too large, potentially introducing risk of harm to caribou


• No questions, comments, concerns raised

Underground reclamation • No questions, comments, concerns raised


• Recommendation to involve Elders in wildlife monitoring • Recommendation to include a full map of the mine site, and what has been reclaimed to date, in

future presentations • Comment that reclamation must consider the ability of caribou to access the formerly avoided

mine sites • Comment that topographic maps can be used to determine where caribou will move • Question as to whether ramps will be installed over areas where infrastructure is covered with fill • Question if there will be artistic renderings of what things will look like after reclamation • Question regarding the length of time it will take for vegetation to re-establish, and if animals

graze on the plants being tested • Question as to what will be done with the road berms • Question about how the power lines and poles will be removed • Question if there will be a recycling program, and, in specific, if power poles could be reclaimed

and given to communities • Question if the river crossing will be dismantled


Ekati Mine Interim Closure and Reclamation Plan Version 3.0 Appendix D: Lessons Learned August 2018



Appendix D Lessons Learned

Capturing the experience of other reclaimed and closed mines is an important element and step in reclamation and closure planning. Lessons learned from reclamation planning at Ekati mine and from actual reclamation and closure planning and execution from other northern mines, are summarized in Table D. These lessons learned have been integrated into Ekati mine reclamation and closure planning within the ICRP. The table provides a current “snap shot” of lessons learned; it will be updated as the mine develops through operations and progressive reclamation, and as more lessons are identified from other applicable mine sites.

Table D: Lessons Learned at Ekati and from Other Projects

# Mine Site Name Activity Which Led to the Learning Lessons Learned Adaptive Management Which Resulted from the Learning

1 Ekati Diamond Mine

Infrastructure development in areas where there are caribou migration paths

Caribou travel through and around the mine site during migration. There is a potential for caribou passage to be impeded or for caribou to be hurt or killed by mining operations infrastructure.

Wildlife access ramps were constructed on haul roads such as Misery and Fox and will be incorporated into the Sable haul road. Inuksuit were constructed around the perimeter of mine components. Indigenous Elders believed that the Inuksuit would be most effective at deterring caribou during spring migration. A site-wide closure planning approach for facilitating caribou movement has been adopted rather than focusing on individual components.


Reducing the volume of hydrocarbon contaminated material during operations and immediately after contamination occurs

Fully remediating operational spills at the time of occurrence, ensuring documentation, reduces requirements at closure.

Spill reporting, spill cleanup, marking the spill location, and record keeping during project construction and operations are conducted at Ekati mine. This will reduce or eliminate the volumes remediated at closure, assist in more accurate planning and costing, and help identify the “hot spot” (or concentrated) spill sites.


Construction, maintenance, operation and monitoring the Panda Diversion Channel (PDC)

The PDC has successfully established fish passage and habitat.

The performance of the PDC was used to design and construct the Pigeon Stream Diversion. Both channels are planned to remain in place post-closure.


Reclamation research plots on the Long Lake Containment Facility (LLCF)

Direct re-vegetation on processed kimberlite and natural colonization is possible on the LLCF. Natural vegetation growth can be an important progressive reclamation mechanism.

The research lessons from the re-vegetation on the LLCF are being used to design the rock/vegetation cover for the LLCF.


Operational monitoring programs Monitoring programs in place at site are effective in detecting changes

The operational monitoring programs can be used to design effective post-closure monitoring programs.


Wildlife monitoring Deposited PK in the non-active areas of the LLCF is stable and safe for caribou access and travel.

Safe movement of caribou across the LLCF can be used to incorporate closure design features into the LLCF rock / vegetation cover.


Progressive reclamation at Old Camp The importance of treating closure and reclamation activities as projects is integrated into mining operations.

This learning is incorporated into approach taken for planning, resourcing, and execution of future progressive reclamation, and final reclamation efforts.





Progressive reclamation at Old Camp Completing activities over multiple construction seasons is more successful than implementing all project components over the course of one construction season.

Realistic time frames incorporated into integrated schedule of activities.


Revegetation efforts Fertilizing and seeding can be effective; however, natural vegetation growth and natural colonization of mosses and lichens can occur, and can be an important progressive reclamation mechanism.

Learning incorporated into approach taken for revegetation planning.


Clean up of Panda/Koala Underground Progressive reclamation staged closure of underground workings when they are no longer required is a successful approach.

This learning will be applied to reclamation of future Ekati underground projects (e.g., Misery).

11 Brewery Creek – Yukon

Dismantling of mine infrastructure and support facilities

Removal of the fence around the process facilities exposed wildlife to a hazard in the lined ponds before the liner was removed. Removing the fence was a condition of the closure plan. Once an active human presence diminished at site, the frequency of wildlife at site increased.

A new fence was installed around the ponds until the lined ponds are reclaimed. A condition of the closure plan for Brewery Creek stipulates the liners in the ponds need to remain in place for 5 years. For other sites, the management approach would be that fencing around ponds should not be removed until reclamation work has been completed


Revegetation of reclaimed slopes The primary driver for successful revegetation efforts at the Brewery Creek Mine is ongoing fertilization over a period of 3 years after seed has been applied. The rate of seed application is less critical than the need for ongoing fertilizer application.

Future revegetation programs will be adjusted to include maintenance fertilizing for two additional years that were not planned.


Implementation of the closure plan using company equipment and labour versus contractor

The costs for a company to reclaim and close the Brewery Creek Mine themselves versus using third party contractors and government required security calculations resulted in a cost reduction of approximately 35% compared to the amount held in security. The costs for the company to implement and execute the closure plan were significantly lower than the costs estimated using third party contractor rates.

n/a


Negotiation and signing a Reclamation Security Release Agreement (RSRA) between the company and the government

An RSRA provides certainty for both the company and government on security release mechanisms and provides significant incentive to the company to accelerate progressive reclamation because there is a mechanism to receive credit for the progressive reclamation.

The company initiated and secured a mechanism to release security through a Reclamation Security Release Agreement (RSRA) with the government, even though this mechanism was not already in place when the government required securities provision by the company at start up of operations.

15 Colomac Mine – NWT

Installation of fence around tailings pond during reclamation period

Caribou became trapped in the corners of the fence by predators (wolves) due to unnatural conditions.

The fence will be removed once the tailings reclamation is complete.




16 Colomac Mine - NWT

Incorporation of TK into pit closure The conceptual pit closure design included a waste rock perimeter berm around three open pits. When consulted, Tłı̨chǫ Elders indicated an alternative configuration, based on caribou behaviour, that significantly reduced the amount of berm material

This learning illustrated the importance and potential benefits of incorporating TK.

17 Con Mine - NWT Groundwater monitoring Changes in surface water and groundwater management may cause some monitoring wells to become dry.

Flexibility may be required in the groundwater monitoring program.

18 Con Mine - NWT Establishment of vegetative islands There were difficulties in acquiring the growth media required to support plant growth from the Yellowknife region.

Choice of closure options and scheduling of these options need to consider difficulties that may be encountered in procurement of required supplies to support option.

19 Con Mine - NWT Surface structures Site infrastructure may have value to the local community. The City of Yellowknife requested the warehouse / shop / administrative area for future use as a public works building.

A Memorandum of Understanding was developed between Miramar Northern Mining Ltd. and the City of Yellowknife for the retainment certain buildings on site.

20 Tundra - NWT Site structures: building demolition and disposal Buildings burnt in place or demolished using an excavator

Burning of waste results in undesirable air emissions.

Burning of waste is now discouraged due to air emissions.

21 Tundra - NWT As part of the Tundra Phase IIB remediation design, a borrow area was regraded to expose the bedrock in high elevation areas. The bedrock dipped more in certain areas than what was assumed, and therefore the overburden was excavated deeper than required resulting in more volume.

It was agreed that a “depth-to-rock” geophysics survey should have been conducted during the design phase to mitigate the over-excavation. This survey information would have been invaluable prior to quarrying, to avoid uncovering previously buried debris.

A “depth-to-bedrock” geophysics survey was conducted and assisted with the remaining excavation work. The geophysics survey was utilized to determine the presence of buried metal debris in the airstrip area, which was partly uncovered during quarrying efforts.

22 Minto Mine - Yukon

Progressive reclamation measures linked to operational development plans for waste rock storage, overburden dumps and tailings management areas

Reduced financial liability for closure costing and bonding. Tax incentive for company to implement progressive closure measures during mine operations.

Review operational plans and procedures to incorporate rigorous assessment and implementation of progressive closure measures.

23 Minto Mine - Yukon

Remediation hydrocarbon-contaminated material during operations and immediately after contamination occurs

Hydrocarbon-contaminated soil material is expected during operations. Establishing a land treatment area for hydrocarbon-contaminated soils during operations ensures prompt cleanup, remediation of material, and reduced closure liability.

An on-site land treatment facility needs to be designed and permitted for hydrocarbon soils during operations to remediate contaminated soils. Treatment reduces the closure liability and provides source material for reuse.

24 Island Copper Mine

Reclaiming of open pit as a pit lake did not proceed as originally designed

Use of fertilization to boost biological productivity led to a significant reduction in metals in the upper levels of the water column.

Adaptive management based on monitoring needs to be incorporated into closure planning.

25 Polaris Mine and Nanisivik Mine

Management of hydrocarbon-contaminated materials

Hydrocarbon-contaminated materials were placed in underground mine workings.

Hydrocarbon contaminated materials are stabilized by encapsulation within the permafrost zone.




26 Nanisivik Mine Beneficial ongoing use of primary infrastructure through transfer to a third party

Opportunities were pursued for beneficial ongoing use of primary infrastructure through transfer to a third party.

Opportunities for beneficial ongoing use of primary infrastructure are to be re-evaluated with successive ICRP updates.

27 Snap Lake Diamond Mine

Closure of Underground Workings The conveyance system remained in the underground workings during reclamation flooding at closure due to the safety risks associated with dismantling it and the minimal environmental effects of it remaining in place.

Proposal to allow for authorization of the Ekati mine conveyance system to remain in place as part of Panda/Koala underground closure. The safety risks at Panda/Koala are similar, and there are minimal potential environmental effects.

28 Snap Lake Diamond Mine

Closure of Underground Workings The experience demonstrated the level of detail needed in tracking closure activities, including providing the GNWT inspector for approval a list of equipment and remediation activities (detailed inventory) to be completed prior to flooding.

A similar detailed inventory of equipment and remediation closure activities will be developed and provided to the GNWT inspector for the closure of the Panda/Koala underground working and eventual pit flooding.

29 Giant Mine Baker Creek Reach 4 Re-alignment Frozen material exposed during excavation melted and caused settlement of excavated areas.

Characterization of frozen materials is needed for sensitive excavations.

30 Giant Mine Baker Creek Reach 4 Re-alignment Survival rates for revegetation were poor due to unusually dry conditions immediately following planting.

Capacity is needed for contingency watering in the case of replanting with species that are sensitive to dry conditions.

PDC = Panda Diversion Channel; LLCF = Long Lake Containment Facility; PK = processed kimberlite; n/a = not applicable; TK = Traditional Knowledge; GNWT = Government of the

Northwest Territories.


Ekati Mine Interim Closure and Reclamation Plan Version 3.0 Appendix E: Research Plans August 2018


2018 Ekati Mine Interim Closure and Reclamation Plan Version 3.0 i

Table of Contents

Table of Contents ..................................................................................................................................................................... i RP 1 – Wildlife Safety ............................................................................................................................................................. 4 RP 2 – Panda/Koala Closure Freshwater Cap Depth ............................................................................................................. 8 RP 3 – Misery and Jay Meromictic Pit Lake Freshwater Cap Depth .................................................................................... 12 RP 4 – Pigeon Waste Rock Storage Area Closure Cover .................................................................................................... 16 RP 5 – Waste Kimberlite Seepage ....................................................................................................................................... 21 RP 6 – Jay Waste Rock Storage Area Co-placement .......................................................................................................... 25 RP 7 – Kimberlite Waste Rock and Coarse Processed Kimberlite Vegetation Physical Stabilization ................................. 27 RP 8 – Long Lake Containment Facility Stabilization Cover ................................................................................................ 29 RP 9 – Long Lake Containment Facility Water Quality ......................................................................................................... 36 References ............................................................................................................................................................................ 38

Tables

Table 1 Linkage to Referred Operational Review Comments and Directives ........................................................................................ 2

Attachments

Attachment 1 Waste Rock Storage Area Co-placement Study Design for the Jay Project



Introduction

The overall aim of reclamation research is to address reclamation uncertainties identified in the closure planning process prior to the preparation of the Final Closure and Reclamation Plan (required two years prior to permanent closure). Reclamation research work has been completed throughout the life of the Ekati mine in a manner that acknowledges the inherent need for the research work to evolve based on the results obtained. Research Plans (RPs) were approved by the Wek'èezhı̀ı Land and Water Board (WLWB) in 2011 as part of Interim Closure and Reclamation Plan (ICRP) Version 2.4 (BHP Billiton 2011). After the first year of implementation of those RPs, a number of changes in format, linkages, and functionality were approved by the WLWB as part of 2012 reclamation progress report (BHP Billiton 2012). The results of completed research studies (as provided in the annual reclamation progress reports) and have been integrated into ICRP Version 3.0 and, where appropriate, these RPs.

Provided below are RPs that have been created to address the uncertainties identified in ICRP Version 3.0. The context and rationale underlying the stated uncertainty is discussed in Chapter 5 of the ICRP and is not repeated herein. It is Dominion Diamond Ekati ULC’s (Dominion’s) intent to continue to update the RPs on an ongoing basis through the annual reclamation progress reports and to more fully amend the RPs as a whole for each update of the ICRP.

The ICRP Version 3.0 RPs are listed below:

• RP 1 – Wildlife Safety

• RP 2 – Panda/Koala Closure Freshwater Cap Depth

• RP 3 – Misery and Jay Meromictic Pit Lake Freshwater Cap Depth

• RP 4 – Pigeon Waste Rock Storage Area Closure Cover

• RP 5 – Waste Kimberlite Seepage

• RP 6 – Jay Waste Rock Storage Area Co-placement

• RP 7 – Kimberlite Waste Rock and Coarse Processed Kimberlite Vegetation Physical Stabilization

• RP 8 – Long Lake Containment Facility Stabilization Cover

• RP 9 – Long Lake Containment Facility Water Quality

Detailed information for each RP is provided below, including the reclamation uncertainty, the research objective(s), a summary of completed or initiated tasks, a description of future research tasks, an estimated schedule, and linkages to other RPs.

Waste rock storage area (WRSA) reclamation research is a key topic area with four individual RPs (RP 4, RP 5, RP 6, RP 7). Two recent operational reviews related to WRSAs (outlined below) resulted in the referral of reviewer comments to reclamation research through ICRP Version 3.0 or WLWB Directives for reclamation research through ICRP Version 3.0:

1. review through the WLWB registry of Dominion’s Waste Rock Storage Area Closure Risk Assessment Framework (WRAF; per Dominion August 2017 written response to comments)

2. WLWB review and approval of Dominion’s 2016 Three-Year Seepage Survey Report (per Dominion written response to comments September 2017 and WLWB January 2018 Reasons for Decision Table 3).

These comments and Directives are addressed through this framework as listed in Table 1.



Table 1 Linkage to Referred Operational Review Comments and Directives

Source Comment ID Topic RP

WRAF review, August 2017 ECCC-13 Water balance 4, 5

WRAF review, August 2017 ECCC-17 Thermal modelling 4, 5

WRAF review, August 2017 ECCC-18 Operational WRSA monitoring 4, 5

WRAF review, August 2017 ECCC-19 Water quality model calibration 4, 5

WRAF review, August 2017 ECCC-2 Model uncertainty, data gaps 4, 5

WRAF review, August 2017 ECCC-22 Model uncertainty 4, 5

WRAF review, August 2017 ECCC-3 ARD/ML source terms 4, 5, 6

WRAF review, August 2017 ECCC-4 Thermal model source terms 4, 5

WRAF review, August 2017 ECCC-8 Monitoring instrumentation 4, 5

WRAF review, August 2017 GNWT-1 Thermal model source terms 4, 5

WRAF review, August 2017 GNWT-14 ARD/ML source terms 4, 5, 6

WRAF review, August 2017 GNWT-19 Water quality source terms 5

WRAF review, August 2017 GNWT-20 Model uncertainty 4, 5

WRAF review, August 2017 GNWT-24 Effects assessment 4, 5

WRAF review, August 2017 GNWT-25 Operational WRSA monitoring 4, 5

WRAF review, August 2017 GNWT-26 Effects assessment 4, 5

WRAF review, August 2017 GNWT-5 Thermal model source terms 5

WRAF review, August 2017 GNWT-6 Thermal model source terms 5

2016 seepage report review, September 2017 GNWT-9 Water quality source terms 5

2016 seepage report review, September 2017 IEMA-11 ARD/ML source terms 4, 5, 6

2016 seepage report review, September 2017 IEMA-14 ARD/ML source terms 4, 5, 6

WRAF review, August 2017 IEMA-16 Model updates 4, 5

WRAF review, August 2017 IEMA-5 Thermal model source terms 4, 5

WRAF review, August 2017 WLWB-11 Water balance 4, 5

WRAF review, August 2017 WLWB-23 Water quality source terms 4, 5

2016 seepage report decision, January 2018 WLWB-A Surface flow patterns 4, 5

2016 seepage report decision, January 2018 WLWB-B Kimberlite sulphur concentrations 5, 6

2016 seepage report decision, January 2018 WLWB-C Internal heat generation 4, 5

2016 seepage report decision, January 2018 WLWB-D Seepage sources (LLCF) 9

2016 seepage report decision, January 2018 WLWB-E Monitoring instrumentation 4, 5

2016 seepage report decision, January 2018 WLWB-F ARD/ML source terms 4, 5 6

WRAF = Waste Rock Storage Area Closure Risk Assessment Framework; ECCC = Environment and Climate Change Canada; GNWT = Government of

the Northwest Territories; IEMA = Independent Environmental Monitoring Agency; WLWB = Wek'èezhı̀ı Land and Water Board; WRSA = waste rock

storage area; ARD/ML = acid rock drainage / metal leaching; LLCF = Long Lake Containment Facility.



Dominion will implement the RPs according to plan and will report on the RPs through the annual reclamation progress reports. Each of the annual reclamation progress reports required under the Water Licence will provide the following:

• a summary of the status and results of each RP

• an appended copy of or reference to stand-alone research reports

• updates, with rationale, to the tasks, schedules, or other aspects of RPs

• description of where research results are being incorporated into closure planning

• description of updates to the ICRP that are based on the research results



RP 1 – Wildlife Safety

Uncertainty

There is uncertainty in determining the best approach to ensuring wildlife safety on and around individual WRSAs (e.g., providing ramps vs. discourage access) and road segments (e.g., smooth surface [esker-like] vs. scarified surface) in closure.

Research/Study Objective

The objective is to utilize the understanding of regional movement patterns and wildlife behaviour to determine the best closure approaches that minimize barriers to movement at regional and local scales, and to minimize potential for injury and mortality as a result of interaction with the reclaimed site. In particular this will drive decisions on the closure activities for individual WRSAs and road segments. Combined with broader regional data collection and operational monitoring (e.g., Wildlife Effects Monitoring Program [WEMP]) that are already in place, the reclamation research will focus on the following:

1. Engage with community members and Traditional Knowledge (TK) holders to evaluate wildlife behaviour and movement patterns in areas of the site that are not active (e.g., Fox development; Pigeon development after completion) and in natural areas that reflect the target reclamation landscape (e.g., existing eskers).

2. Establish wildlife cameras at locations that support evaluation of closure-specific questions.

3. Conduct behavioural surveys that support evaluation of closure-specific questions.

4. Advance preliminary designs for roads and WRSAs and seek feedback through further engagement with community members and TK holders.

Overview of Tasks

Completed/Initiated Tasks

As described in more detail in Chapter 5 of ICRP Version 3.0 or past annual progress reports, the following activities have been conducted that feed into wildlife safety research:

• 2012 EKATI Diamond Mine: Literature Review – Exclusion Barriers and Wildlife

• RP 7.2 Wildlife Closure Objectives and Criteria: Tasks 1 and 2 - Review of Existing Mines and the Ekati Wildlife Effects Monitoring Program (Rescan 2013)

• What’aa Esker Research Project (ICRP Section 5.5.3.2)

• Traditional Knowledge Elders Group (TKEG) sessions (ICRP Sections 5.5.3.1 and 5.8.3)

• establishing caribou crossings on Misery, Sable, and Jay roads (ICRP Section 5.8.4.1)

• WEMP annual reports (ongoing)



• wildlife observations at the Long Lake Containment Facility (LLCF) reclamation trials (e.g., 2017 annual progress report)

Future Planned Research Tasks

1. Caribou Engagement Workshop

Building from the success and learnings of past vegetation engagement workshops, Dominion will organize a caribou engagement workshop. The purpose of the workshop will be to invite key community members, TK holders, and regulatory specialists to the Ekati mine site to conduct a multi-day site visit. A portion of the workshop will specifically focus on closure questions related to WRSA and road features. If possible (depending on logistics), the program will also include site visits to control areas of target habitat (e.g., existing eskers). Key learnings and opportunities for further engagement will be recorded and reviewed as part of the workshop.

The date of the caribou engagement workshop is to be determined, and will be optimized where possible to coincide with other engagement activities, as well as the timing of mining activity on site. Workshop materials, notes, and outcomes will be documented in the subsequent annual progress report.

2. Wildlife Cameras

A large wildlife camera program has been established under the WEMP. Most of these cameras have been sited to address questions related to effects of mine operation, and are focused around areas of current activity. Some cameras have been established at the LLCF, which supports evaluation of potential use post-closure. As part of reclamation research, additional wildlife cameras will be established at locations that support evaluation of closure-specific questions. Initially, these will include:

• wildlife movement from the north towards and around the Sable development

• wildlife movement around Pigeon development, especially after mining ceases

Relevant findings from the cameras will be summarized in the annual progress reports and discussed with the TKEG and community groups.

3. Behavioural Surveys

Information on caribou behaviour has been collected at the Ekati mine since 2001; however, methods have changed slightly over the years (e.g., focal sampling vs. scan sampling). Collected behavioural data from the Ekati mine (typically around 20 surveys per year), as well as from the Diavik mine, will be reviewed, with recommendations developed for how future survey efforts could be focused on moving forward to support evaluation of closure-specific questions. In particular, Dominion wildlife technicians will be directed to specifically collect behavioural surveys when there are incidental observations of wildlife use on or adjacent to mine components in non-active areas of the site (which to date have not been prioritized, as the focus has been on potential operational effects).

Results from the behavioural surveys will be included in the annual WEMP reports. Findings from the behavioural surveys that are relevant to closure and reclamation planning will be summarized in the annual progress reports and discussed with the TKEG and community groups.



4. Wildlife Safety Closure Design

a) WRSAs

On the basis of results from Tasks 1, 2, and 3, a preliminary design will be advanced for a specific WRSA or subset of WRSAs. The design(s) will include:

• description (including visuals) of proposed measures to provide (or prevent) access onto / egress from the WRSA, and how this fits within the local and regional context

• design criteria utilized to ensure wildlife safety (e.g., minimize potential for injury/mortality)

The preliminary design(s) will be presented to the TKEG and community groups, describing how previous input was incorporated and providing opportunity for feedback and recommendations. Results from this engagement will then be incorporated into the design, and into planning for subsequent WRSAs.

b) Roads

On the basis of results from Tasks 1, 2, and 3, a preliminary design will be advanced for reclamation of roads across the mine site. The preliminary design(s) will include:

• description (including visuals) of the various reclamation approaches that will be used reclaim the segments of road, including removal of berms, final side slopes, running surface, caribou crossings, stream crossings, etc.

• design criteria utilized to ensure wildlife safety (e.g., minimize potential for injury/mortality)

• identification of specific road segments and the proposed closure measures to be implemented, and how this fits within the local and regional context

The design(s) will be presented to the TKEG and community groups, describing how previous input was incorporated and providing opportunity for feedback and recommendations. Results from this engagement will then be incorporated into the design.

Linkages to Other Research/Studies

The reclamation research studies listed below are directly related to this study. There may be additional research or operational studies related to this study that will be used in developing the findings for this study.

• Pigeon WRSA Closure Cover (RP 4)

• Jay WRSA Co-placement (RP6)

• Kimberlite Waste Rock (KWR) and Coarse Processed Kimberlite (CPK) Vegetation Physical Stabilization (RP 7)

• LLCF Stabilization Cover (RP 8)



Project Research Schedule

This study is designed to collect data over the next 10+ years to help drive decisions that will feed into the Final Closure and Reclamation Plan. The Final Closure and Reclamation Plan is required two years prior to planned permanent closure of the Ekati mine, which is currently scheduled to be 2032 (i.e., two years prior to closure in 2034) according to the current life of mine (LOM) schedule.

Task-specific schedule notes are as follows:

• Task 1 (caribou engagement workshop) timing is to be determined, and will be optimized where possible to coincide with other engagement activities, as well as the timing of mining activity on site. Workshop materials, notes, and outcomes will be documented in the subsequent annual progress report.

• Task 2 (wildlife cameras) will be initiated in summer of 2019 and will continue annually, with revisions as appropraite based on LOM planning and analysis of monitoring results. Relevant findings from the cameras will be summarized in the annual progress reports.

• Task 3a (recommendations from the review of behavioural survey data) will be completed in 2019 and incorpoated into the annual progress report.

• Task 3b (collection of behavioural survey data) will continue annually. Results from the behavioural surveys will be included in the annual WEMP reports; findings that are relevant to closure and reclamation planning will be summarized in the annual progress reports.

• Task 4a (WRSA preliminary design) will be completed subsequent to the completion of Task 1, with an initial goal of having the design and any associated engagement incorporated into the next update of the ICRP (e.g., 2021)

• Task 4b (road preliminary design) will be completed subsequent to the completion of Task 1, with an initial goal of having the design and any associated engagement incorporated into the next update of the ICRP (e.g., 2021)



RP 2 – Panda/Koala Closure Freshwater Cap Depth

Uncertainty

There is potential uncertainty that the 30 m freshwater cap over processed kimberlite (PK) materials at the time of closure for Panda and Koala pit lakes will not result in water quality that will meet closure criteria. This could be because of poorer than anticipated porewater quality released through PK consolidation or poorer than anticipated runoff from WRSAs and exposed pit walls.


1. Based on the results of ongoing operational monitoring, verify whether the currently designed 30 m freshwater cap depth at closure for Panda and Koala pit lakes remains valid.

2. If necessary, determine an appropriate freshwater cap depth at the time of closure for Panda and Koala pit lakes.

Overview of Tasks


Water Quality Modelling for Beartooth, Panda, Koala North, and Koala Pits

Water quality models for Beartooth, Panda, Koala North, and Koala pits were included in a modelling report (Golder 2018a) with the 2017 closure and reclamation progress report (Dominion 2018a) in January 2018 to evaluate the post-closure pit lake water quality following placement of freshwater caps over the deposited PK in these facilities.

Updated Modelling to Support Processed Kimberlite Deposition Planning in Panda, Koala North, and Koala Pits

The updated water quality models evaluated the post-closure water quality conditions following placement of freshwater caps over the deposited PK in these facilities. Updated water quality models, including the development of hydrodynamic models, for Panda, Koala North, and Koala pit lakes were included in a subsequent report (Golder 2018b) to support PK deposition planning for these pits (i.e., the Panda and Koala Deposition Study as per Part H, Condition 32 of the Water Licence). The objectives of the water quality modelling were as follows:

• Investigate the behaviour of the fine processed kimberlite (FPK) in each pit lake, once deposited.

• Estimate consolidation of FPK, leading to settlement and porewater release.

• Predict the quality of the resulting supernatant water, in combination with other inflow sources.



Supplemental to any pit closure modelling completed previously for pits where PK deposition is planned, FPK consolidation and porewater release after deposition was accounted for in the closure water quality modelling using estimates from the application of the one-dimensional, large-strain consolidation modelling software CONDES0. The influence of FPK settling on long-term pit lake water quality was then evaluated using GoldSim modelling software. Provided below is an overall summary of the closure water quality modelling effort:

• Large-strain consolidation modelling indicates that the FPK will settle up to 110 m in Panda Pit, 90 m in Koala North Pit, and 115 m in Koala Pit at 200 years from the end of deposition. Consolidation will continue beyond 200 years, albeit at declining rates.

• Consolidation of FPK will release porewater into the overlying pit lake as it settles. Water quality models were developed to evaluate the influence of FPK settling on long-term water quality in the pit lakes, which will be connected by a surface channel in post-closure.

• In the absence of final water quality closure criteria, Ekati mine water quality benchmarks were applied to screen the modelled post-closure water quality projections. Predicted water quality conditions in Panda Pit and the combined Koala / Koala North pits indicate that several constituents will increase above surface water quality benchmarks in the long term (i.e., concentrations of aluminum, copper, chromium, and iron). However, the risk of these exceedances to cause adverse effects to aquatic life in the pit lakes is considered negligible to low.

• The modelling results that led to these conclusions were based on several conservative assumptions. These assumptions provide a moderate to high level of confidence that, while the precise concentrations predicated are not expected to be realized, the actual concentrations are likely to be lower.

• Monitoring of the inputs to the pit lakes between now and the start of filling, then during the filling period, will allow Dominion to update models, verify or refine predictions, and adaptively manage the inflows to improve water quality of the supernatant water if necessary.

Beartooth Pit Processed Kimberlite Deposition Monitoring

Solids settlement monitoring data in Beartooth Pit are collected by completing a sonar bathymetric survey. The purpose of the monitoring is to assess the surface elevation of submerged PK solids currently contained in the pit, estimate the remaining disposal capacity of the pit, and provide site-specific in situ consolidation properties for operational and closure planning. Results include a detailed bathymetry contour map of the PK minewater column. The most recent results are appended to the 2017 annual closure and reclamation progress report (Dominion 2018a).




1. Monitoring and Data Collection

The following monitoring data will be collected to provide further refinement of model input terms:

• Operational monitoring data are currently being collected at Surveillance Network Program (SNP) Station 0008-Be4. This station at Beartooth Pit monitors water quality within the pit during its use as a processed kimberlite containment area (PKCA) and for minewater management. Monitoring is conducted twice annually (once under ice cover and once during open water) at two depths (one near the surface and one at depth) and includes physical water column profiling and collection of water quality samples. Stations Jay-0008 and Jay-0009 will be for monitoring water quality in Panda Pit and Koala Pit, respectively, during the use of these pits as PKCAs, and will have the same monitoring requirements as Station 0008-Be4. Water quality monitoring data will continue to be collected during PK deposition, as required by the Ekati mine SNP for Beartooth Pit and Panda/Koala pits (when used as a PKCA). Additionally, water quality samples with depth will be collected as needed to further the understanding of minewater quality during active PK deposition. After the end of PK deposition and minewater management in Beartooth Pit and Panda/Koala pits, pit closure water quality data will be collected during back-flooding, until back-flooding has been completed.

• Regular bathymetric surveys, in-pit water elevations and the quantities of PK, slurry water, and other minewater entering the pits will continue to be routinely recorded and used to calibrate water and mass balances for operational and closure planning. The scheduling of the bathymetric surveys will be at a schedule that provides data on a timely basis for modelling updates or other planning needs; this may be annually or every second year.

• Data on density and rate of consolidation and porewater quality will be collected within deposited PK at Beartooth Pit. Collected information will be used to calibrate and further refine the estimates for consolidation and porewater release quantities and quality. It is planned that these monitoring data will be collected in Beartooth Pit after PK operations have concluded.

• Seepage from the Panda/Koala/Beartooth WRSA is sampled on a minimum twice per year basis and the data evaluated according to the requirements of the Water Licence. The accumulated dataset forms the basis of predictions of future WRSA seepage quality entering Panda and Koala pit lakes post-closure. Additional collection of seepage monitoring data in support of further refinement and calibration of the WRSA seepage term is planned. This effort would include installation of continuous seepage flow monitoring with additional seepage water quality sampling in the open water season.

2. Freshwater Cap Evaluation

The site-specific monitoring dataset will be used to further refine input terms and develop an update the existing models for Panda and Koala Pit Lake water quality predictions. The updated predictions will be used to address whether the currently designed 30 m freshwater cap depth at closure for the Panda and Koala Pit Lakes remains appropriate.


There are no direct linkages to other research studies.




This study is designed to make beneficial use of site-specific data collected through mine operations to validate or amend the currently designed freshwater cap depth for closure of Panda and Koala pit lakes.

Operational monitoring under Task 1 of this study is underway for Beartooth Pit and the Panda/Koala/Beartooth WRSA. Monitoring of Panda/Koala North and Koala pits will commence with commencement of PK deposition. Closure monitoring data will be completed at the end of PK operations during and after back-flooding has been completed. All in-pit monitoring work will be dependent on safe access to the in-pit water level as determined by a geotechnical assessment of pit walls and ramps. For the Panda/Koala/Koala North pits, in-pit monitoring work will commence once the in-pit water level has risen to a safely accessible elevation, which may require extended time and more rigorous geotechnical evaluation. Monitoring data will continue to be reported annually through the seepage reports and the Water Licence annual reports, and annual reclamation progress reports.

Task 2 of this study will be undertaken at an appropriate time indicated by the monitoring results and not later than when the PK surface in any of Panda, Koala North, or Koala pits reaches 50 m below final overflow elevation. This will ensure that the modelling will be updated and the depth of freshwater cap confirmed or amended in a timely manner. This approach provides:

• adequate time for collection of a site-specific operational dataset upon which to base model updates

• assurance that the study will be completed with time to implement operational adjustments if necessary; the limit on the data collection timeframe is conservative given that current modelling (incorporating site-specific data for Beartooth Pit and WRSA seepage) supports a 30 m freshwater cap at time of closure.

The results of Task 2 of this study will be reported through the annual progress reports and the Final Closure and Reclamation Plan.



RP 3 – Misery and Jay Meromictic Pit Lake Freshwater Cap Depth

Uncertainty

Meromictic pit lakes are those in which high-density minewater is sequestered in the lower layer of the pit (monimolimnion) and does not mix with the overlying freshwater in the upper layer of the pit (mixolimnion). A key consideration is the depth of freshwater that is required to ensure that the meromixis will remain stable and that the closure water quality criteria are achieved in the upper layer.

Potential uncertainty that the proposed 60 m freshwater cap over minewater in Misery Pit will not result in water quality that will meet closure criteria due to runoff from WRSAs and exposed pit walls, or diffusion from the monimolimnion. As water is transferred from the upper level of Misery Pit to Jay Pit at closure to make room for the freshwater cap, the plan also affects Jay Pit, which is located under Lac du Sauvage.

The design depth of the freshwater cap over residual higher density minewater is 60 m for closure of Misery Pit and 60 m for closure of the Jay pit (below pit rim) based on predictive water quality modelling. The operating timeframe for the Jay Project provides the opportunity to validate or, if necessary, amend the current design depths based on site-specific monitoring data collected during mine operations.


The main objective of this study is to determine, based on monitoring data collected during operations, the appropriate depth of the freshwater cap to maintain meromictic conditions and meet closure water quality criteria for Misery Pit Lake and for Jay Pit in Lac du Sauvage.

1. Based on the results of ongoing operational monitoring, verify whether the currently designed freshwater cap depths for Misery and Jay pit lakes remains valid.

2. If necessary, determine appropriate freshwater cap depths for closure of Misery and Jay pit lakes.

Overview of Tasks


To support Environmental Assessment (EA) and permitting of the Jay and Misery Underground (MUG) projects and closure planning, water quality modelling studies were completed to predict water quality for Jay and Misery pits in post-closure (DDEC 2014a; Golder 2016, 2017).

Modelling for Jay and Misery pits was reported in the Jay EA DDEC 2014a) and Water Licence amendment application (Golder 2016) and review processes and the MUG Project Water Licence amendment application (Golder 2017). These modelling studies combined water balance and detailed water quality models to predict water quality based on estimates for each of the inputs.



Misery Pit Water Quality Modelling

Key aspects of the post-closure water quality modelling for Misery Pit Lake were as follows:

• Misery Pit will become the primary minewater management facility for the Jay Project, and contents will also include minewater generated from MUG.

• At closure, the minewater stored in in the upper part of Misery Pit will be pumped to the bottom of Jay Pit to create room for a freshwater cap.

• Pumped inflow sourced from Lac du Sauvage and natural surface runoff will be used to create a 60 m freshwater cap.

• The stability of meromixis was evaluated through hydrodynamic modelling of the first 200 years after back-flooding using CE-QUAL-W2 model and mass balance calculations over 5,000 years using a vertical mass-balance slice spreadsheet model.

A key objective of the site water management plan for MUG and Jay Pit is to establish meromictic conditions in the Misery Pit to preclude minewater in the denser, lower layer of the pit (monimolimnion) from mixing with the overlying freshwater in the upper layer of the pit (mixolimnion) and thereby potentially affecting the closure objective for the pit (i.e., that the water quality of Misery Pit is safe for use by fish, wildlife, and people). The minewater with elevated total dissolved solids (TDS) is predicted to remain in the lower part of Misery Pit Lake following the creation of the freshwater cap due to density stratification, thereby creating a meromictic lake. Modelling to date indicates meromictic conditions will form and remain stable with a 60 m freshwater cap (Golder 2016, 2017).

Based on modelling work completed, meromixis is predicted to form and remain stable into post-closure (i.e., 200 years) in Misery Pit. Model results indicate that following back-flooding, TDS and other water quality constituents (e.g., chloride, phosphorus, and nitrate) will slowly increase in the mixolimnion, reaching steady-state conditions as a result of gradual upward diffusion from the monimolimnion over time (Golder 2017). Although some constituents show slight increases relative to closure surface water quality predictions, operational monitoring and adaptive management strategies required under the Water Licence (e.g., freshwater cap optimization studies) provide added confidence that Misery Pit will satisfy closure goals and objectives and not pose an environmental risk. Into the long-term (e.g., 5,000 years), natural groundwater migration from Misery Pit reduces TDS in the monimolimnion, producing a well-mixed waterbody that will continue to meet closure goals and objectives.

Jay Pit Water Quality Modelling

Key aspects of the post-closure Jay Pit water quality model are as follows:

• At closure, minewater will be transferred from Misery Pit (i.e., water consisting of groundwater inflows and other sources of water) to create the lower monimolimnion layer.

• Pumped inflow to fill the upper layer of Jay Pit and the diked area in Lac du Sauvage is sourced from Lac du Sauvage, and will take approximately three years to fill.

• The stability of meromixis in Jay Pit in closure and into the long term was evaluated through hydrodynamic modelling of the first 200 years after back-flooding using CE-QUAL-W2 model and mass balance calculations over 5,000 years using a vertical mass-balance slice spreadsheet model.



A key objective of the site water management plan for Jay Pit is to establish meromictic conditions to preclude minewater in the denser, lower layer of the pit (monimolimnion) from mixing with the overlying freshwater in the upper layer of the pit (mixolimnion) and thereby potentially affecting the closure objective for Lac du Sauvage (i.e., the water quality of Lac du Sauvage is safe for use by fish, wildlife, and people). The minewater with elevated TDS is predicted to remain in the lower part of Jay Pit following the creation of the freshwater cap due to density stratification.

Based on modelling work completed, meromixis is predicted to form and remain stable into post-closure (i.e., 200 years) in Jay Pit. Into the long term (e.g., 5,000 years), meromixis in Jay Pit is projected to become stronger.


1. Monitoring Data Collection

SNP and Aquatic Effects Monitoring Program (AEMP) monitoring will be conducted throughout operations which will be used in future modelling updates.

As per Water Licence W2012L2-0001 (WLWB 2018), SNP monitoring will be conducted that will inform future water quality modelling updates. The quality of the water pumped from Lynx Pit to the bottom of Misery Pit at the end of the MUG Project will be measured. During mining of Jay Pit, SNP Station Jay-0003 at the mine inflow sump will provide monitoring data for the water being pumped to the bottom of Misery Pit, and will be reflective of the deep groundwater inputs as Jay Pit is being mined. Station Jay-0004 at the Jay runoff sump will monitor the quality of the water entering the top of Misery Pit from Jay Pit. Stations Jay-0005a and -0005b measure Misery Pit water quality that will be pumped to Lac du Sauvage during Discharge, and will be representative of the upper layer of Misery Pit during the latter years of the use of Misery Pit as a minewater management facility. Station Jay-0006 is for in-pit monitoring at Misery Pit, in order to monitor the quality of water and to understand formation of meromixis in Misery Pit during its use for minewater management. Monitoring will be conducted twice annually (once under ice cover and once during open water) at two depths (one near the surface and one at depth) and will include physical water column profiling and collection of water quality samples.

During construction and operations of the Jay Project, water quality monitoring will be conducted in Lac du Sauvage under the AEMP (Dominion 2018a), which will be representative of the freshwater pumped to place the freshwater cap on Misery and Jay pits. Monitoring will also be conducted during back-flooding and prior to the reconnection of Misery Pit Lake to Lac de Gras. Similarly, monitoring will be conducted during pumping of water from Misery Pit to the bottom of Jay Pit and during back-flooding of Jay Pit and diked area and prior to breaching of the Jay Dike and reconnecting to Lac du Sauvage.

2. Freshwater Cap Optimization

Part H, Condition 22 of the Water Licence requires that at least two years prior to Discharge from Misery Pit during the Jay Project, a Misery Pit water quality report is submitted in accordance with Schedule 6, Condition 5. This required model update will allow calibration of the models and updates to source term inputs based on monitoring data collected to date.

The updated Misery Pit water quality modelling, combined with all collected monitoring data, will serve as the basis for the completion of the fresh water cap optimization study. The optimization study will use the developed water quality models for Misery and Jay pits to evaluate the fresh water cap depths fresh required to maintain meromictic conditions and water quality in Misery Pit and also Jay Pit. As outlined in Measure 4-2b of the Report of Environmental Assessment and Reasons for Decision (MVEIRB 2016), the optimization study will ensure compatibility with traditional land uses.




There are no research linkages at this time.


Monitoring data collection will be initiated during the start of using Misery Pit for water management (end of MUG operations and start of Jay Pit dewatering). An update to the Misery Pit water quality model and is required two years prior to discharge from Misery Pit. The freshwater cap optimization will be completed after the Misery Pit update and is planned to be initiated 2.5 to 3 years prior to closure. This will allow the results to be incorporated into the Final Closure and Reclamation Plan.



RP 4 – Pigeon Waste Rock Storage Area Closure Cover

Uncertainty

There is uncertainty regarding the type of cover, if any, required for closure of the Pigeon WRSA.


1. Utilize the LOM operating timeframe to collect post-construction monitoring data that will be integrated into updated seepage quality predictions.

2. Determine the need for a cover over the Pigeon WRSA for closure of the facility.

3. If a cover is determined to be necessary, identify the preferred type of cover such that engineering designs can be developed.

4. Integrate results of related research and design projects into the cover determination and design.

5. Provide a final cover determination and design no later than the Final Closure and Reclamation Plan.

Overview of Tasks


Pigeon Waste Rock Geological Model and Geochemical Characterization

The initial geological model that was the basis of the initial assessment and permitting of the Pigeon Project (2000) anticipated a sharp distinction among metasediment, diabase, and other rock types to be mined. At that time, separate geochemical characterizations (including humidity cell tests) were developed for each rock type, which were consistent with characterizations at other sites such as Misery. The geological model was revised in 2013 to reflect updated geological interpretations and remains the current model. The 2013 geological model anticipated that nearly all waste rock to be mined would be a geologically inter-banded mixture of granite and metasediment that could not be separated during mining because of the fine scale of interbanding. Previous geochemical static test results were re-characterized and additional static and kinetic (humidity cell tests) were conducted according to the revised geological model. The interbanded granite/metasediment mixture was characterized as non-potentially acid generating (non-PAG) for up to 70% metasediment in the rock mixture. The geological model and waste rock geochemical characterizations are described in the Waste Rock and Ore Storage Management Plan (WROMP; Dominion 2018b).



Waste Rock Storage Area Closure Cover Concepts

Based on the subsequently revised initial geological model, a conceptual closure cover of 5 m of granite waste rock, which is the same as the Misery WRSA, was developed for initial assessment of the Pigeon Project in 2000. The initial cover concept was based on the premise that metasediment waste rock would be placed into the WRSA in consolidated layers that required a thermal cover to protect against acid rock drainage (ARD). For subsequent operational permitting of the Pigeon WRSA in 2013, the closure cover concept was revised to better align with the revised geological model, specifically that there would be no distinct granite mined from Pigeon Pit and, also, that there would be a relatively large quantity of glacial till. The 2013 closure cover concept remained based on the premise that a thermal cover was necessary and proposed to achieve this with a layer of glacial till covered by a physically protective layer of granite. The 2013 cover concept required smoothing of side slopes to accommodate placement of glacial till. Variants of the combination till/granite cover concept were subsequently developed to accommodate design changes to Pigeon Pit.

Waste Rock Storage Area Construction Monitoring

Operational monitoring of material types and quantities excavated from Pigeon Pit commenced in 2015 in accordance with the requirements of the WROMP. The results to date verify the geological model (i.e., predominantly interbanded granite and metasediment) and geochemical characterizations (i.e., interbanded rock mixture is classified as non-PAG). WRSA seepage surveys have been undertaken in accordance with the Water Licence, and the results to date indicate that ARD is not occurring.

Previous Waste Rock Storage Ara Research Plans

Reclamation research to date has developed useful information for understanding and addressing closure risks related to WRSAs at the Ekati mine. This work culminated in the development by Dominion of a WRAF. The WRAF developed several technical methods related to understanding WRSA closure risks, as follows:

• WRSA water balance prediction method

• WRSA thermal prediction method

• WRSA seepage quality source terms prediction method

• WRSA environmental risk assessment method

The technical methods were broadly circulated and feedback was provided to Dominion through the WLWB registry. The Pigeon WRSA has not yet been evaluated through the WRAF since the WRSA is under construction; however, the WRAF provides a means of future evaluation of the as-built Pigeon WRSA, using technical methods updated to accommodate reviewer feedback.


The tasks described below are planned as the means of addressing the study uncertainty and objectives (as stated above). The study tasks are intended to evolve in response to results of this or other studies, or in response to changing circumstances at the Ekati mine; therefore, updated task descriptions may be developed from time to time when appropriate and these would be described in the annual reclamation progress reports.



1. Construction Waste Rock and Seepage Monitoring

Operational monitoring during construction of the WRSA will continue to provide essential information for this study. Operational monitoring will include waste rock monitoring conducted and reported in accordance with the WROMP and seepage monitoring conducted and reported in accordance with the Water Licence. Geological mapping within the open pit will also be completed.

2. Post-construction Monitoring

The post-construction timeframe within the LOM schedule provides the opportunity to monitor the performance of the WRSA through an extended (10-year) timeframe, during which time all of the operational personnel, equipment, and support infrastructure are available at the Ekati mine. This monitoring will include ongoing seepage sampling in accordance with the Water Licence, physical stability/erosion monitoring, and wildlife monitoring. Monitoring data will be reported annually through the seepage reports and also documented in the annual reclamation progress reports.

An evaluation of post-construction monitoring needs will be conducted at completion of WRSA construction, which will consider frequencies, special studies, and instrumentation for seepage, physical stability, and thermal monitoring. Post-construction monitoring will, at a minimum, meet regulatory requirements. Dominion’s determination of monitoring needs in excess of regulatory requirements, if necessary, will be reported through the annual progress reports.

3. Drill Investigation

If the post-construction monitoring results indicate that an internal investigation of the WRSA would be useful to this study, a drill investigation will be planned to collect data on conditions within the WRSA after a stabilization period. The investigation would be generally modelled after drill investigations at the Fox (2015) and Misery (2018) WRSAs. The investigation results will be reported in the annual reclamation progress reports and integrated into this study and, where relevant, other studies.

4. Predictive Modelling and Risk Assessment

Predictive modelling and closure risk assessment for the Pigeon WRSA will be completed through the WRAF at an appropriate time indicated by the monitoring data collected, and not later than for the Final Closure and Reclamation Plan. This work will be reported in the annual reclamation progress reports and/or the Final Closure and Reclamation Plan and will include the following steps:

a) Update predictive modelling methods and predictions for the Pigeon WRSA as follows:

i. WRSA water balance, including updated consideration of

1. site-specific monitoring data and relevant external information

2. progressive wetting of internal flowpaths

3. retention of water as pore-ice

4. potential shallow subsurface flow beneath or at the toe of the WRSA

5. seepage flow patterns beyond WRSA toe

6. scale of prediction uncertainties



ii. WRSA thermal evaluation, including updated consideration of


2. climate source terms

3. material source terms and localized effects

4. depth of seasonal active layer thaw

5. conductive and convective heat transfer

6. heat of exothermic reactions

7. projections and conclusions regarding internal freezing


iii. WRSA seepage quality source terms, including updated consideration of


2. potentially acid generating (PAG)/Non-PAG differentiating criteria

3. particle size gradations

4. effective neutralization potential (NP)


6. scale of prediction uncertainties.

b) Complete predictive modelling of WRSA seepage quality and quantity.

c) Complete WRSA closure risk assessment.

5. Final Cover Determination and Design

The findings of this study, other related studies at Ekati mine and relevant external studies will be integrated and evaluated to provide a final determination of the need for a closure cover, the most appropriate type of cover, and the final design of the closure over. This work will intend to resolve the study uncertainty and fully satisfy the study objective. The final determinations and design will consider:

• monitoring information collected through Tasks 1 through 3 above

• predictive modelling and risk assessment results generated through Task 4 above

• results and findings of related reclamation research or other studies conducted at the Ekati mine

• relevant publicly available findings of research or case studies at other locations

• relevant outcomes of community engagement and TK programs

• any other relevant data or information

The final determinations and design will be developed following Task 4 of this study and will be reported in the annual progress reports and/or the Final Closure and Reclamation Plan.




The Ekati mine reclamation research and operational studies listed below are directly related to this study. There may be additional research or operational studies related to this study that will be used in developing the findings for this study.

• Wildlife Safety (RP 1)

• Waste Kimberlite Seepage (RP 5)

• KWR and CPK Vegetation Physical Stabilization (RP 7)

• LLCF Water Quality (RP 9)


This study is designed to make use of the extended (10-year) post-construction timeframe to collect site-specific monitoring information in support of the final determinations and design. This study will be completed no later than for the preparation of the Final Closure and Reclamation Plan, which is required to be submitted two years prior to planned permanent closure of the Ekati mine (closure is currently scheduled for 2034). This study may be completed sooner if monitoring information and other evaluations indicate that sufficient information is available to proceed to final determinations and design.


• Task 1 is underway and will be undertaken while the WRSA is under construction, currently anticipated to extend to 2021 or 2022.

• Task 2 will be undertaken on an ongoing basis following construction of the WRSA and extending to preparation of the Final Closure and Reclamation Plan, currently scheduled for submission in 2032 (i.e., two years prior to permanent closure).

• Task 3 is a one-time investigation that would occur during the post-construction monitoring timeframe at a time indicated appropriate by the collected monitoring information and not later than for preparation of the Final Closure and Reclamation Plan, currently scheduled for submission in 2032 (i.e., two years prior to permanent closure).

• Task 4 will follow Task 3, if conducted, at an appropriate time indicated by the monitoring data collected, and not later than for preparation of the Final Closure and Reclamation Plan, currently scheduled for submission in 2032 (i.e., two years prior to permanent closure).

• Task 5 will be completed following Task 4 and not later than for preparation of the Final Closure and Reclamation Plan, currently scheduled for submission in 2032 (i.e., two years prior to permanent closure).



RP 5 – Waste Kimberlite Seepage

Uncertainty

The closure risk related to seepage from exposed kimberlite at the Fox WRSA and the coarse kimberlite reject storage area (CKRSA) has been described through various studies, including the WRAF, and the evaluations support the closure measures described in the ICRP (i.e., physical stabilization cover). The extended LOM timeframe (anticipated to extend to 2034) provides opportunity to refine the risk descriptions through continued monitoring and update of predictive models.


1. Continue to collect seepage and other monitoring data through the LOM timeframe.

2. Update the WRAF methods related to seepage from exposed kimberlite at the Fox WRSA and the CKRSA.

3. Update the closure risk descriptions for seepage from exposed kimberlite at the Fox WRSA and the CKRSA for integration into final closure planning.

Overview of Tasks


Kimberlite Geochemical Characterization

Kimberlite is clearly and consistently classified as non-PAG based on static and kinetic test results. Kimberlite contains proportionally high carbonate content and low sulphur content. The geochemical characterization does not vary between the different operational grain size fractions (i.e., FPK, CPK, and KWR). Test results are documented in the Ekati mine WROMP for CPK and KWR (Dominion 2018b) and in the Ekati mine Wastewater and Processed Kimberlite Management Plan for FPK (DDEC 2017). The characterization is based on static testing of 590 samples and kinetic testing of 11 samples.

The geochemical test results indicate that a number of metals can be leached from kimberlite under neutral pH conditions at concentrations elevated relative to Canadian Council of Ministers of the Environment (CCME) guidelines, which include aluminum, arsenic, cadmium, copper, iron, nickel, selenium, and silver.

Fox Drill Investigation

A drill investigation was carried out at the Fox WRSA in 2015 that collected data on conditions within the WRSA and installed monitoring instrumentation. The program consisted of geotechnical and geochemical components. In total, six vertical boreholes with depths ranging from 7 to 65 m were drilled using sonic drill rig. Soil, rock, and water samples were collected for geotechnical and geochemical analyses. Within the completed boreholes, new ground temperature cables and water piezometers were installed. The findings were carried forward directly into the WRAF described below, which includes closure seepage quality predictions and ecological risk assessment for the Fox WRSA and the CKRSA.



Monitoring

Operational monitoring and sampling of material types and quantities excavated from Fox Pit was undertaken throughout mine operations in accordance with the requirements of the WROMP (2001 to 2014). Operational monitoring and sampling of CPK is ongoing. The results form part of the geochemical characterization dataset and confirm the non-PAG classification of kimberlite. WRSA seepage surveys have been undertaken in accordance with the Water Licence and the results to date indicate that ARD is not occurring. Monitoring results were carried forward directly into the WRAF described below, which includes closure seepage quality predictions and ecological risk assessment for the Fox WRSA and the CKRSA.

Waste Rock Storage Area Closure Risk Assessment Framework

Monitoring and reclamation research has developed useful information for understanding and addressing closure risks related to WRSAs at the Ekati mine. This work culminated in the development by Dominion of a WRAF. The WRAF developed several technical methods related to understanding WRSA closure risks, as follows:

• WRSA water balance prediction method

• WRSA thermal prediction method

• WRSA seepage quality source terms prediction method

• WRSA environmental risk assessment method

The technical methods were broadly circulated and feedback was provided to Dominion through the WLWB registry. The predictions of seepage quality and assessment of risk for the Fox WRSA as a whole, areas of exposed KWR at the Fox WRSA, and the CKRSA are based in the site-specific monitoring/investigation information and support the closure measures described in the ICRP (i.e., physical stabilization cover).


1. Monitoring

The timeframe within the LOM schedule provides the opportunity to monitor seepage from exposed kimberlite at the Fox WRSA and the CKRSA through an extended (10-year) timeframe during which time all of the operational personnel, equipment, and support infrastructure are available at the Ekati mine. This monitoring will include ongoing seepage sampling in accordance with the Water Licence, physical stability/erosion monitoring, and wildlife monitoring. Monitoring data will be reported annually through the seepage reports and also be documented in the annual reclamation progress reports.

Monitoring information at the Fox WRSA will represent the performance of the WRSA as a whole (i.e., integrated granite and metasediment areas) as well as areas of mostly kimberlite (i.e., the kimberlite “low-grade” area). Monitoring information will reflect ongoing stabilization of the WRSA over time post-construction and will be useful for validating calibration of the predictive models.

The CKRSA will be under continued construction for some or all of the LOM timeframe and, as a result, monitoring information will be expected to reflect potentially transient operating conditions except in locations where seepage may originate predominantly from completed areas. Nonetheless, this monitoring information will provide useful information on short-term seepage conditions and, potentially, comparative data between exposed CPK versus KWR.



An ongoing evaluation of monitoring needs will be conducted through each annual data review, which will consider frequencies, special studies and instrumentation for seepage, physical stability and thermal monitoring. Monitoring will, at a minimum, meet regulatory requirements. Dominion’s determination of monitoring needs in excess of regulatory requirements, if necessary, will be reported through the annual progress reports.

2. Predictive Modelling and Risk Assessment

Predictive modelling and closure risk assessment for exposed kimberlite at the Fox WRSA and the CKRSA through the WRAF will be updated at an appropriate time indicated by the monitoring data collected, and not later than for the preparation of the Final Closure and Reclamation Plan. This will include the Fox WRSA as a whole in addition to areas of exposed KWR. This work will be reported in the annual reclamation progress reports and/or the Final Closure and Reclamation Plan and will include the following steps:

a) Update predictive modelling methods and predictions for the Fox WRSA and CKRSA as follows:

i. WRSA/CKRSA water balance, including updated consideration of


2. progressive wetting of internal flowpaths

3. retention of water as pore-ice

4. potential shallow subsurface flow beneath or at the toe of the WRSA/CKRSA

5. seepage flow patterns beyond WRSA/CKRSA toe


ii. WRSA/CKRSA thermal evaluation, including updated consideration of


2. climate source terms

3. material source terms and localized effects

4. depth of seasonal active layer thaw

5. conductive and convective heat transfer


7. projections and conclusions regarding internal freezing


iii. WRSA/CKRSA seepage quality source terms, including updated consideration of


2. particle size gradations

3. effective NP





b) Complete predictive modelling of WRSA/CKRSA seepage quality and quantity.

c) Complete WRSA/CKRSA closure risk assessment.



1. Pigeon WRSA Closure Cover (RP 4)

2. Jay WRSA Co-placement (RP 6)

3. KWR and CPK Vegetation Physical Stabilization (RP 7)

4. LLCF Water Quality (RP 9)


This study is designed to make use of the extended (10-year) post-construction timeframe to collect site-specific monitoring information to refine the description of risks related to seepage from exposed kimberlite at the Fox WRSA and the CKRSA. This study will be completed no later than for the preparation of the Final Closure and Reclamation Plan, which is required to be submitted two years prior to planned permanent closure of the Ekati mine (closure is currently scheduled for 2034). This study may be completed sooner if monitoring information and other evaluations indicate that it is appropriate to update the risk descriptions.


• Task 1 is underway and will be undertaken on an ongoing basis extending to preparation of the Final Closure and Reclamation Plan, currently scheduled for submission in 2032 (i.e., two years prior to permanent closure).

• Task 2 will be conducted at an appropriate time indicated by the monitoring data collected, and not later than for preparation of the Final Closure and Reclamation Plan, currently scheduled for submission in 2032 (i.e., two years prior to permanent closure).



RP 6 – Jay Waste Rock Storage Area Co-placement

Uncertainty

Licensing of the Jay Project identified outstanding reviewer uncertainty regarding the methodology for determining net neutralization potential for waste rock to be mined at Jay Pit and placed into the Jay WRSA. The determination of net neutralization potential affects operational details of the co-placement plan. As a result of the outstanding reviewer uncertainty, the WLWB required, as a Condition of the Water Licence, the submission for approval of a “Jay WRSA Co-Placement Study Design” (Condition H.4, approval pending).


The Jay Waste Rock Storage Area Co-placement Study Design for the Jay Project is provided as Attachment 1. The study design was developed to meet the requirements of the Ekati mine Water Licence amended to include the Jay Project (WLWB 2017). The overall objective of the co-placement study design is “to optimize the co-placement strategy, determine the target NP/AP [neutralization potential/acid potential] ratio and identify the scale of mixing that will prevent Acid Rock Drainage from the Jay Waste Rock Storage Area.”

Overview of Tasks

The study design has been developed to make use of existing materials (e.g., waste rock from nearby, geologically analogous Misery Pit) and existing site-specific monitoring data (e.g., seepage monitoring data from the Misery WRSA) to develop a dataset that can be used to refine the Jay WRSA design in a timeline amenable to development of Jay Pit. The study design consists of a comprehensive mineralogical and leach testing study to be completed in advance of mining at Jay Pit, using waste rock from Misery Pit. Study components also include testing of waste rock produced during the early stages of mining at the Pit, and investigation of the Misery WRSA after the completion of mining at Misery Pit.


The Jay co-placement study design (Attachment 1) has been prepared and submitted to the WLWB in response to the Water Licence amendment decision letter and the requirements of the Water Licence (Schedule 3, Condition 6). In advance of WLWB approval of the co-placement study, samples for the geochemical study were collected from the Misery WRSA in November 2017, in order to ensure that metasediment would be available for sample collection. The samples underwent static testing and are being stored in sealed containers at an analytical laboratory until further testing can begin. The Misery WRSA drilling and instrumentation program was completed in February of 2018 and geochemical laboratory testing working and thermal monitoring data collection is ongoing.


The remaining co-placement study components as outlined in Attachment 1 are summarized below.



1. Geochemical Testing

A laboratory-scale geochemical testing program will be undertaken to determine the effective NP of blasted waste rock from the Ekati mine and will include the following phases:

• Phase I – Material Characterization

• Phase II – Detailed Mineralogical Analysis

• Phase III – Laboratory Leach Testing

• Phase IV – Future Geochemical Testing

2. Waste Rock Placement Optimization and Monitoring

Investigations of further potential construction optimizations for the co-placement zone. The optimization process will be aimed to maximize the NP/AP ratios within the co-placement zone to mitigate ARD potential, while enabling efficient progressive capping of the WRSA during construction. This optimization process will incorporate any results and conclusions from Phase I, II, and III geochemical tests (specifically the results of mixed waste rock tests). The results of the optimization evaluation will be included in the co-placement study report.

An overall operational monitoring reporting plan will be developed as part of the co-placement study, which will ultimately be included in the SNP and annual Ekati Water Licence reporting frameworks. The operational monitoring plan will be described in the co-placement study report.

3. Misery WRSA Storage Monitoring Program

The Misery WRSA investigation and thermal monitoring data will be complementary to the geochemical testing program. The geochemical results of the Misery WRSA investigation will be specifically evaluated with respect to the sensitivity of the effective NP/AP ratio to imperfect mixing for the proposed co-placement management plan.


There are no research linkages at this time.


On approval of the study design by the WLWB, the remaining tasks of the study will be initiated on a timeline that is amenable for the Jay WRSA construction schedule. A detailed proposed schedule for the co-placement study design is provided with the submitted study design (Attachment 1).



RP 7 – Kimberlite Waste Rock and Coarse Processed Kimberlite Vegetation Physical Stabilization

Uncertainty

Vegetation has been shown to establish itself (naturally and through active planting) in FPK located at the LLCF and hence it is considered as part of a final stabilization cover. Due its larger grain size and other differing physical properties, it is unknown whether vegetation can be used to physically stabilize exposed KWR at the Fox WRSA and on CPK at the CKRSA.


The research objective is to determine how to provide a physically stable surface on exposed KWR and CPK using vegetation.

Overview of Tasks


1. Vegetation Growth Trials

The feasibility of using vegetation for physical stabilization will be evaluated by implementing small-scale field research vegetation growth trials on KWR and CPK. The research trials will incorporate the methods used for previous field research trials at the LLCF including the following:

• Trial locations—Trial plots will be established at selective KWR locations at the Fox WRSA and within CPK located at the northern end of Cell B of the LLCF. The CPK material located at the northern end of Cell B was placed in 2009 to facilitate surface water drainage, and would likely provide a representative test area of the potential final CPK surface at the CKRSA.

• Size—Small-scale field trial plots (i.e., 3 m by 3m) will be initially established and, depending on the initial results of the trial plots, additional selective larger scale trial areas could be implemented.

• Vegetation species:—The trials will be broadcasted with seed at a consistent rate to evaluate their vegetation growth. Vegetation species that will be selected are those that have shown successful growth on FPK located in Cell B of the LLCF and those that could have potential to grow in the coarse-grained materials.

• Lakebed sediment amendments—Due to its larger grain size and poor moisture retention capability, the use of lakebed sediments as amendment to increase the moisture holding capacity will be evaluated. Additional amendments including surficial till maybe also evaluated.

• Surface roughening—The surfaces of the trial plots areas will be roughened to increase the potential for moisture retention and natural colonization of vegetation.



• Monitoring—Monitoring activities will include the collection of baseline KWR and CPK soil samples to measure moisture holding capacity and soil chemistry in the various trial plots. Once seeded, the percent ground cover by vegetation will be completed with the trials on an annual basis. Soil sampling will be completed at selected intervals to monitor changes in moisture holding capacities and or soil chemistry.


The reclamation research study listed below is directly related to this study. There may be additional research or operational studies related to this study that will be used in developing the findings for this study.

• LLCF Stabilization Cover (RP8)


It is planned that vegetation trials will be implemented in 2019 to make beneficial use of the extended ten year LOM. Similar to the research trials at the LLCF it is anticipated that a three to five year monitoring timeframe will be required to draw conclusions. Monitoring results will be reported in the annual reclamation progress reports and the study will be completed no later than for the Final Closure and Reclamation Plan. The overall monitoring results will guide the implementation of any additional research tasks or the implementation of any progressive reclamation activities.



RP 8 – Long Lake Containment Facility Stabilization Cover

Uncertainty

Ability of vegetation in the LLCF cover to provide sufficient long term stabilization of deposited processed kimberlite.


Determine the vegetation elements of the LLCF final cover system to physically stabilize processed kimberlite.

Overview of Tasks

Completed/Initiated Research Tasks

LLCF research work in Cell B was initiated in 2012. Regular status updates on LLCF research tasks have been provided as part of submitted reclamation research reports in annual reclamation research reports. Provided below is a summary of the research tasks, monitoring activities completed, and key results.

Rock and Cover Combination Trials

To investigate alternative cover design options, a study was developed in 2013 involving three rock windrow configurations and vegetation: 1) tundra boulder field with vegetation cover, 2) rock grids with vegetation cover, and 3) rock rows with vegetation cover. The goals of all three configurations are the same: to limit erosion by wind and water, to encourage snow accumulation, and to provide habitat for additional plant species, whether introduced intentionally or colonizing the sites naturally.

Vegetation monitoring has been conducted annually since 2014. Percent ground cover is the primary method used to describe vegetation. It is derived by averaging repeated estimates of the portion of ground covered by individual species within a 0.10 m2 Daubenmire frame. Ground covered by plant litter, bare ground, and bryophytes and lichens is also recorded. At some sites permanent 30 m transects have been established along which the data are acquired, and at others the frame is placed randomly.

There appears to be no appreciable difference in vegetation and litter cover buildup between the rock rows, rock grids, and boulder field rock configurations. Seeded Fult’s alkali grass (Puccinellia distans) maintained a cover of 23% to 30%, comparable to 2016. Cover of seeded goose grass (Puccinellia borealis) is less productive than Fult’s alkali grass and declined from 20% live cover in 2016 to 12% live cover in 2017. Litter cover is building, and exposure of bare ground is decreasing significantly for all trial sites. The boulder field is a better fit aesthetically, however, comparable to the natural distribution of rock on the undisturbed landscape. It also creates more microsites for natural plant colonization. Unseeded areas in the rock rows and rock grids are being colonized naturally by alkali grasses (a mixture of the native goose grass and introduced Fult’s), whose fine seed is easily disbursed by wind. Rates of living vegetation and litter build up appear to be a year behind those of seeded sites. Organic amendment of PK with Alfalfa Green pellets has resulted in a sustained increase in growth of Fult’s alkali grass over the two-year period from 2016 to 2017.



Plant Species Trial

Plant species trials are an ongoing component of reclamation research at the Ekati mine. A number of such trials have been set up in Cell B of the LLCF to investigate the suitability of several native plant species for use in revegetating the PK in the cell. The results to date are encouraging: although some species are clearly better adapted to conditions in Cell B than are others, at least a few individuals of every species planted have established. Inoculation with commercially available mycorrhizae does not appear to enhance birch and willow survival nor growth, but the opposite is true of commercially available rhizobium used to inoculate Maydell’s oxytrope (Oxytropis maydelliana).

Natural Colonization

Over the long term, a key measure of revegetation success at the Ekati mine will be the proportion of groundcover comprising indigenous native plant species. Therefore, creating conditions that encourage colonization of disturbed areas by local native plants is an important objective. Around 2004, a native northern alkali grass (goose grass) from the surrounding tundra began colonizing the west side of the Cell B beaches. Field observations indicated that natural colonization of goose grass continue to spread past the water boundary running north–south along the west side of Cell B.

Cell B vegetation growth and the rates of colonization have been evaluated by using satellite imagery and the Normalized Difference Vegetation Index (NDVI). In general, the NDVI analysis confirmed an overall increase in the rate of natural colonization from goose grass was observed along the east side of Cell B with major gains forming a beltline with the western border.

Soil Amendment Trials

To test the effectiveness of calcium nitrate, alfalfa pellets and hypsum as soil amendments a series of six 2 m by 4 m trial plots were established in Cell B of the LLCF in 2013. One half of each replicate plot (2 m by 2 m) was row-seeded with annual barley at 30 kg/ha, and one half was broadcast seeded with Fult’s alkali grass at 10 kg/ha and lightly raked to incorporate the seed. Fertilizer (16-16-16 NPK) was broadcast at 100 kg/ha.

The PK amendment plots were first monitored in August 2013. At that time, soil samples were collected from 0 to 20 cm in each of the replicate plots and the vegetation was monitored by measuring percent groundcover, counting seedlings, and measuring average plant heights. Data was collected from within three 0.1 m2 frames placed randomly in each plot. The same data were collected in August 2014 and August 2015, with the exception that the seedling count was not conducted in the alkali grass and percent survival of the seedlings planted in both years was determined.

Soil chemistry data from samples collected in 2017 indicate that the chemical amendments have leached from the soil profile and dissolution of gypsum and/or calcium nitrate is likely complete. Although the amended plots had sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) values modestly lower than the unamended PK in 2017, SAR in all but the calcium nitrate plus Alfalfa Green treatment still exceeds the sodic soil threshold and ESP indicates sodic conditions still exist in every treatment. In 2015, decreases in SAR to levels well below the sodic threshold were likely due to leaching caused by unusually high rainfall experienced at the mine site during August when sampling was conducted. That effect was temporary, however, and under the more normal conditions experienced in 2016, soil salts concentrations rebounded and appear to have stabilized.



Glacial Till Topdressing Trial

The suitability of glacial till as a reclamation substrate has been assessed at several locations on the mine site: at the rock pad reclamation study area, the Panda/Koala WRSA, and the Tercon laydown. In all cases, till was found to be coarse grained with a variable rock content and without any chemical properties that would impair plant growth (Martens 2014). Over the long term, plant growth on till has been satisfactory, but establishment is impeded by the hard surface crust that develops upon its drying. That condition can be ameliorated, however, by roughening or ridging the surface by deep ripping. To investigate the till topdressing cover option, two studies were established in Cell B in 2013: one with till placed over PK and one with till placed on a layer of coarse kimberlite rejects (CKR) over the PK. The rationale for including CKR in the topdressing study is that it may serve as a capillary break, controlling the possible upward migration of PK salts into the till topdressing (Martens 2014).

In 2013, insufficient time had passed for appreciable vegetation to establish, so monitoring that year consisted of a simple seedling count and collecting samples for baseline soil chemistry data. Soil samples were collected from 0 to 15 cm and 15 to 30 cm from each of the four (2 seed types × 2 locations) plots. Percent ground cover by live vegetation and litter was measured in 2014, 2015, and 2017, and soil sampling was repeated. Percent survival of seedlings planted in 2015 and 2016 has been documented annually.

Seeded grass has established and natural colonization by alkali grasses is also occurring. Survival rates of planted seedlings is comparable to that observed in other locations. Average rates of survival of treated seedlings (inoculated with mycorrhizae or treated with worm castings) are slightly better than for those untreated. Browsing by rodents is a significant cause of seedling mortality. Depending on seedling availability additional upland plant species should be added to the species trials within small fenced enclosures. Surface roughening using large rocks might provide some protection for young plants on the exposed till on CKR plot. Changes to soil chemistry due to upward migration of salts from the PK into the overlying till are more pronounced in the till over PK plot than in the till on CKR over PK plot, although current salts concentrations should not impair plant growth in either plot.

Cover Crops Trial

Cover crops are used extensively in land reclamation to provide temporary ground cover until permanent vegetation is established. The primary reasons for establishing vegetation on a bare substrate are to control erosion and provide micro niches for colonizing plants and to add organic matter to the soil environment. Organic matter serves to stimulate and/or maintain soil biological activity; it is a long-term source of plant nutrients, helps to buffer soil pH, and improves a soil’s moisture holding capacity, structure, and tilth. The annual cover crops being grown at Ekati have limited potential to persist and/or spread beyond the seeded areas. Due to the cool, short growing season, they are not expected to produce viable seed and without cultivation the odds of any viable seed establishing are reduced significantly.

Cover crop trials have been are an ongoing component of reclamation research in Cell B of the LLCF. Since 2014 barley (Hordeum vulgare), triticale (X Triticosecale), annual ryegrass (Lolium multiflorum), and fall rye (Secale cereale), in combination with fertilizer and/or commercially available mycorrhizae, have been tried with varying but limited success (for more information see DDEC 2015, 2016). Fall rye has been of particular interest because it is a biannual crop that requires cold treatment or winter to induce its seed set. Growth during the first year (or until it receives a cold treatment) is limited to a low growing rosette of leaves. The next season, plants produce a single stem and seed head then die. Under normal growing conditions, fall rye provides good ground cover and leaves a good cover of litter after setting seed and dying. Fall rye planted in Cell B in the summer of 2013 and 2014 failed to over-winter, however, and therefore did not produce enough biomass to provide appreciable ground cover. In summer 2015, fall rye was planted again on approximately 2.1 ha on the north side of the pilot study area in Cell B, and within that area four 10 m by 10 m fertilized plots were established. On two of the plots 10-30-10 (NPK) fertilizer was applied at 100 kg/ha, while the other two plots received 450 kg/ha 10-30-10 fertilizer, at which rate the equivalent of 60 kg/ha nitrogen was applied.



Mine-Generated Organic Matter

In 2015 a commercial composting system was implemented at Ekati to improve waste processing efficiency at the Ekati mine site. A potentially beneficial use of mine-generated organic material (MGOM) is as a soil amendment in the PK tailings which, in their unamended state, contain very little organic matter. In June 2016, a trial was established to test various application rates of MGOM and to assess the value of incorporating the material by tillage. Following application and final tillage, the plots were seeded with a perennial grass. To date, there are no discernable patterns for the number of seedlings established for each MGOM application rate or for whether the MGOM was rototilled into the PK or left on the surface. In 2017, an additional trial intended to compare various application rates of MGOM and commercially available compost at different landscape locations was established.

Mycorrhizae Trials

Approximately 85% of all vascular plant species in undisturbed, natural ecosystems form symbiotic relationships, called mycorrhizas, with a group of soil fungi known collectively as mycorrhizae. The mycorrhizae colonize the roots of the host plant and in exchange for carbon from the plant their hyphae extend laterally in all directions from the roots effectively increasing the plant's root surface area and therefore its ability to extract nutrients and water from the surrounding soil.

A trial intended to provide insight into the potential for beneficial soil fungi (mycorrhizae) to enhance plant growth on reclamation sites at the Ekati mine site was started in June 2017. Five plots containing locally harvested willow stakes inoculated with indigenous mycorrhizae were established at various locations within the pilot study area in Cell B. After only one growing season it is not possible to ascertain any affects attributable to mycorrhizae, but monitoring data does show one-year survival to be greater in upslope versus downslope locations.

Surface Drainage Channel Trials

The need for surface draining trials became evident during the spring of 2015, when a channel conveying freshet water developed along the south side of the main staging area. Surface water erosion was becoming an issue that could impact other vegetation trials if not contained to specified channels. To mitigate these concerns, efforts are being made to construct drainage channels throughout Cell B that will allow the conveyance of water during high flow periods and maintain the stability of vegetated sections of the PK. Channels were initially selected based on natural drainage patterns but have been excavated out farther to allow for a higher volume of flow through the designated channel. A series of smaller braided channels have been developed through low-lying areas to direct flow into the main water conveyance channels. Once dug out, the channels have been fortified using a combination of rock placement, selective vegetation, and erosion control matting. The main goal of the drainage channel trials is to contain surface water erosion and allow for water passage through Cell B in predictable patterns. So far, the combination of physical (rock placement) and bioengineered mechanisms (planting of willows, grasses, sedges, etc.) has yielded encouraging results, with seemingly stable banks and an influx of sediment deposition within the channels. Trials have been set up along two separate channels 250 to 300 m in length to gauge the success of the surface drainage channels in mitigating erosion to other portions of Cell B and in promoting vegetative growth.

Surface Roughening

Surface roughening allows for the slight changes to the topography and can aid in managing surface water flow. For seeded areas of Cell B in particular, the surface is roughened by way of towing harrow implements with a utility task vehicle (UTV). Through this process, the top 3 to 5 cm of PK is loosened and left in an uneven manner with ridges that deflect surface water flow. This form of erosion control is only temporary as with the minimal amount of material displaced, water flow can begin carving rills or gullies though low lying areas. The utilization of mounds and holes throughout the selected sites of Cell B has been identified as a mitigation to surface erosion. This usage is largely due to the ability to reduce the stored energy of moving water in high flow periods by dispersing surface water flow paths. Establishing a



series of mounds and pits can also provide other benefits such as improving microsite drainage and aeration, increasing soil and air temperature, improving nutrient availability, minimizing effects of competing vegetation, and allowing vegetation establishment through improved seed catchment. Mounding patterns generally consists of a concave hole approximately 30 to 45 cm both deep and wide, alternating with convex mounds across the landscape. Implementation of mounding has been carried out through with hand tools using the Kubota B26 Tractor dedicated to the reclamation research program at Cell B.

Kugluktuk Community Engagement

Kugluktuk Elders visited the Ekati mine in July of 2017. The focus of the site tour was the Cell B LLCF reclamation research area with the goal of familiarizing the Elders with the LLCF reclamation research program. Elders from Kugluktuk were able to share some of their TK from residing near saline coasts. Building on this initial engagement effort, Dominion has filed a research application with Government of Nunavut to complete research work in the community of Kugluktuk in 2018. This research program is outlined in remaining research tasks section of this research plan.


1. Kugluktuk TK Research Project

The Kugluktuk TK research program’s overall aim is to incorporate TK through partnership with local community experts. It is proposed for the Ekati mine staff and its vegetation consultant experts to visit Kugluktuk and with the help of community members to collect a small amount of seed (less than 1 kg) and (possibly) a few live specimens of plants found growing in salt-affected areas along and near the coastline near Kugluktuk. Community guides will share TK of local vegetation and work with the Ekati mine team in selecting the areas of highest potential. Collected material will be transported directly back to the Ekati mine site, where seed will be processed and stored and live specimens planted and monitored as part of the ongoing plant species trials being conducted in the PK at the Ekati mine site. It is expected that seed will be planted in spring/early summer 2019 although, time permitting, some seed may be planted in fall 2018. Survival and growth of the resulting plants will be monitored annually for at least three years.

2. Mycorrhizae Trials

Monitoring should be continued and additional species are to be included in the trial, as planned. This is a long-term project that is expected to take multiple years to gauge growth responses. Collection of native mycorrhizae from the area surrounding the Ekati mine will continue for future to be used in the establishment of trials.

3. Drainage Channel Trials

Monitoring will continue for established channels conveying surface water within Cell B. Construction of another research channel at the northern portion of Cell B is planned. The two constructed research channels will be evaluated for additional research design modification such as placement of more rock armouring and seedlings based on observations following high flow periods, such as freshet.

4. Stabilization of Lowland Areas

Along the east edge of Cell B, there are many lowland areas that have been observed to be perpetually saturated and contain high levels of salinity. These areas have been identified as a challenge to physically stabilize, with difficulty establishing vegetation covers. Current ideas to stabilize lowland areas include a combination of rock placement, vegetation with riparian or halophytic species, placement of glacial till piles, and soil amendments.



5. Organic Matter Incorporation Trials

Cover crop trials will continue to be utilized to build up a vegetative litter layer and add organics to the substrate. Additional trials with fall rye combined with agricultural rates of fertilizer will be implemented in upcoming growing seasons. Monitoring of growth will continue into the future.

Plough down of naturally colonized goose grass will be implemented moving forward. Strips of established grasses will be ploughed and tilled into the PK to add to the vegetative litter layer, increase the volume of organic matter, and improve nutrient cycling. These areas are to be monitored to gauge the ability of natural vegetation to re-establish into long-term physical stabilizers of the PK substrate.

Trials intended to compare various application rates of MGOM and commercially available compost at different landscape locations have been established. Annual monitoring of both trials should proceed before the establishment of more trials is considered.

6. Rock and Cover Combination Trials

Established species trials conducted within small fenced areas will continue and should consider upland versus lowland planting locations in plots developed in the future. Annual monitoring of natural colonization in the rock rows and rock grids to continue through upcoming years. Soil sampling should be repeated in upcoming years.

7. Surface Roughening

Erosion control methods such as harrowing and mounding will be evaluated year-by-year. Monitoring will provide an understanding of success rates based on instances of visible erosion and vegetation establishment. Harrowing will continue prior to seeding any significant stretches of Cell B. Mounding will be completed selectively in areas with the highest potential for erosion due to surface water flow. The use of mechanized equipment such as the B26 tractor will allow for efficient establishment of mounds along larger plots of land within Cell B in the upcoming years.

8. Glacial Till Topdressing Trial

Depending on seedling availability, additional upland plant species should be added to the species trials within small fenced enclosures. Surface roughening using large rocks might provide some protection for young plants on the exposed till on CKR plot.

Changes to soil chemistry due to upward migration of salts from the PK into the overlying till are more pronounced in the till over PK plot than in the till on CKR over PK plot, although current salt concentrations should not impair plant growth in either plot. Full monitoring of the plots should be repeated in 2019 and beyond.

9. Plant Species Trial

Plant species trials are an ongoing component of reclamation research at the Ekati mine. A number of such trials have been set up in Cell B of the LLCF to investigate the suitability of several native plant species for use revegetating the processed kimberlite in the cell. The results to date are encouraging: although some species are clearly better adapted to conditions in Cell B than are others, at least a few individuals of every species planted have established. More time and additional monitoring is needed before definitive conclusions regarding a species' suitability can be drawn. Species trials will continue to be expanded to include as many potential revegetation plants as is operationally feasible with an emphasis on native species. Ongoing, periodic monitoring will also be required.



10. Natural Colonization

The evaluation of natural vegetation and growth rates of will continue on an annual basis using satellite imagery and the NDVI and continued field observations. The utilization of NDVI analysis will also allow for the growth rate evaluation of other potential enhancements implemented including crop cover trials, surface roughening, rock placement, fertilization, and sources of propagule.



• Wildlife Safety (RP 1)

• LLCF Water Quality (RP 9)


RP 8 is anticipated to proceed for multiple years in the future until closure design for PKCAs is determined. The overall intent of the LLCF reclamation research initiatives is to develop reclamation designs that can be implemented as progressive reclamation activities throughout active mine operations. Future trial establishment monitoring and progressive reclamation schedules will be based largely on the overall analysis and conclusions drawn from the program and disclosed in the annual LLCF reclamation research report, which is submitted as part of the annual closure and reclamation progress report.



RP 9 – Long Lake Containment Facility Water Quality

Uncertainty

Implications for water quality in the LLCF after closure are uncertain.


The objective is to evaluate the long-term LLCF water quality in closure using numerical modelling tools.

Overview of Tasks


Koala Watershed Water Operational Quality Model

A water quality model for the LLCF was refined in 2004 and then updated in 2012. Since 2012, the model has been developed incrementally for water management through operations. A comprehensive update of the LLCF water quality prediction model (LLCF load balance model) and of a model representing the chain of lakes lying downstream of the LLCF (LLCF downstream model) was completed in 2017 (ERM 2017). The two models are collectively called the Koala watershed model. The updated model supersedes all previous versions of the water quality model and will be used in future applications. The predictions made by the water quality model are based on many assumptions, primarily those of future loadings to the LLCF from the processing plant discharge.

Long Lake Containment Facility Closure Water Quality Model

As described in more detail in Chapter 5 of ICRP Version 3.0, preliminary closure water quality modelling of the LLCF has been completed (ERM 2013). The model results predict that with cessation of pumping PK and minewater at the end of operation, natural runoff will dominate the water balance of the LLCF, resulting in the dilution of water quality variables within the facility. In support of the closure water modelling, research has also been to characterize the porewater concentrations of the LLCF and evaluate the influence of PK weathering on water quality (DDEC 2014b, Appendix G DDEC 2016).

Long Lake Containment Facility Drilling Investigation

A winter investigation program was completed in 2013 to assess the permafrost development in the LLCF and to characterize FPK and porewater concentrations in Cell B of the LLCF. Thermistors for ongoing monitoring were installed. Investigation results indicated permafrost aggradation into Cell B and evidence of weathering and porewater expulsion in the porewater concentrations (DDEC 2014b).




1. LLCF Monitoring Data Collection

Operational water quality monitoring data collected as part of the SNP in the LLCF (Cells C, D, and E) and in the Receiving Environment as part of the AEMP (i.e., Leslie, Moose, Nema, and Slipper lakes) will continue. At closure there will be small residual ponds and surface water channels to convey water through the reclaimed LLCF cells. Water quality will be monitored in the residual ponds (when developed) and constructed channels to inform the development of FPK source terms for the closure water quality model.

When PK deposition in Cell C and Cell A is completed, an investigation program to evaluate the rate of permafrost aggradation and the porewater quality will be completed. Given the successful result of permafrost aggradation in Cell B, it is planned that this work will be completed in the summer field season and not require a winter drill investigation.

2. LLCF Closure Water Quality Model Update

The LLCF closure load balance model will be updated and will incorporate the most current results from the operational model, and all model runs will start when mine operations are expected to cease and continue until steady state conditions in closure are simulated. The updated model will be used to predict water quality within Cells D and E of the LLCF after the end of active LLCF operations. The key components of the modelling update will comprise:

• Incorporation of LLCF stabilization cover design and any potential implications on the LLCF water balance because of the vegetation and rock cover design.

• Development of FKP source terms—The source terms will evaluate the potential effects of PK weathering on the surface water quality and will be developed from collected historical monitoring data including porewater concentrations, water quality in residual ponds and surface channels, and water quality within Cells C, D, and E of the LLCF.

• Incorporation of permafrost aggradation monitoring data for Cells A, B, and C—If required, this model will incorporate future predictions of permafrost aggradation if the monitoring data indicate unfrozen conditions.


The reclamation research study listed below is directly related to this study. There may be additional research or operational studies related to this study that will be used in developing the findings for this study.

• LLCF Stabilization Cover (RP 8)


An update to Koala watershed water operational quality model is scheduled to occur during the Ekati mine Water Licence renewal in 2021. The LLCF closure water quality model update will be developed to help drive decisions that will feed into the Final Closure and Reclamation Plan. The Final Closure and Reclamation Plan is required two years prior to planned permanent closure of the Ekati mine, which is currently scheduled to be 2032 (i.e., two years prior to closure in 2034) according to the current LOM schedule.



References

BHP Billiton. 2011. Ekati Diamond Mine, interim closure and reclamation plan. Version 2.4. Submitted to Wek’èezhìı Land and Water Board. Project 0648-105-01. August 2011.

BHP Billiton. 2012. Ekati Diamond Mine, 2012 annual interim closure and reclamation plan progress report.

DDEC (Dominion Diamond Ekati Corporation). 2014a. Developer’s assessment report for the Jay Project. Prepared by Golder Associates Ltd., Yellowknife, NWT, Canada. October 2014.

DDEC. 2014b. Ekati Diamond Mine: Long Lake Containment Facility investigation 2013. Prepared by EBA Engineering Consultants Ltd. and ERM Consultants Ltd. for Dominion Diamond Ekati Corporation, Yellowknife, Northwest Territories.

DDEC. 2015. Ekati Diamond Mine: 2015 Closure and Reclamation Progress Report. Prepared by Dominion Diamond Ekati Corporation: Yellowknife, Northwest Territories.

DDEC. 2016. Ekati Diamond Mine: 2016 closure and reclamation progress report. Prepared by Dominion Diamond Ekati Corporation, Yellowknife, Northwest Territories.

DDEC. 2017. Wastewater and Processed Kimberlite Management Plan Version 7.0. October 2017.

Dominion (Dominion Diamond Ekati ULC). 2018a. Ekati Diamond Mine 2017 closure and reclamation progress report. 22 January 2018.

Dominion (Dominion Diamond Ekati ULC). 2018b. Waste Rock and Ore Storage Management Plan. Version 9.0. March 2018.

ERM (ERM Consultants Canada Ltd). 2013. Modelling water quality and water quantity impact of infilling Fox Pit Lake with LLCF water. Memorandum prepared for Lukas Novy P. Eng., EKATI Senior Environmental Advisor – Reclamation and Closure. 17 December 2013.

ERM. 2017. Ekati Diamond Mine: 2017 Koala watershed water quality model. Prepared for Dominion Diamond Ekati ULC by ERM Consultants Canada Ltd., Yellowknife, Northwest Territories.

Golder (Golder Associates Ltd.). 2016. Jay Project - Water Licence water quality model updates. Submitted to Dominion Diamond Ekati Corporation. 2 June 2016.

Golder. 2017. Ekati Mine - Misery Underground water quality model updates. Submitted to Dominion Diamond Ekati Corporation. 14 August 2017.

Golder. 2018a. Ekati Mine – pit lake closure water quality modelling. Prepared for Dominion Diamond Ekati ULC. 17 January 2018.

Golder. 2018b. Ekati Mine – supernatant water quality modelling of Panda, Koala, and Koala North pit lakes at closure. DRAFT Technical Memorandum to Annie Larrivée, Dominion Diamond Ekati ULC, from Shadi Dayyani and Jerry Vandenberg, Golder Associates. 10 August 2018.



Martens HE. 2014. Ekati Diamond Mine revegetation research projects – 2013. Prepared for BHP Billiton Diamonds, Inc., Yellowknife, NT, Canada by Harvey Martens & Associates Inc. Calgary, AB.

MVEIRB (Mackenzie Valley Environmental Impact Review Board). 2016. Report of Environmental Assessment And Reasons for Decision. Dominion Diamond Ekati Corp. Jay Project. Yellowknife, NWT. February 2016.

WLWB (Wek'èezhı̀ı Land and Water Board). 2017. Type A Water Licence W2012L2-0001 (Amendment to incorporate Ekati Jay Project). Dominion Diamond Ekati Corporation. 6 July 2017.

WLWB. 2018. Reasons for Decision. Land Use Permit and Water Licence Application for the Ekati Misery Underground Development. http://registry.mvlwb.ca/Documents/W2012L2-0001/W2012L2-0001%20-%20Ekati%20-%20Water%20Licence%20-%20Amendment%20-%20Misery%20UG%20-%20RFD%20and%20Recommendation%20to%20Minister%20-%20Jul%2012_18.pdf. 12 July 2018.





2018 Ekati Mine Interim Closure and Reclamation Plan Version 3.0

Attachment 1 Waste Rock Storage Area Co-placement Study Design for the Jay Project

Record #:HSE RCD ENV 810 Document Owner: Environment Department Date:04-Oct-17 Template # EKA TEM 1852.13

October 4, 2017

Dear Ms. Camsell-Blondin Re: W2012L2-0001: Dominion Diamond Ekati Corporation - Waste Rock Storage Area Co-Placement Study Design for the Jay Project, Ekati Mine, NT Dominion Diamond Ekati Corporation (DDEC) is pleased to provide the Wek’èezhìi Land and Water Board (WLWB) the Waste Rock Storage Area Co-Placement Study Design for the Jay Project. The Co-Placement Study Design is a requirement of Part H, Condition 4 of the Amended Water Licence W2012L2-0001 which states the following: “ Within 90 days of the effective date of Amendment #4, the Licensee is to submit to the Board for approval a Jay Waste Rock Co-Placement Study Design to optimize the co-placement strategy, determine the target NP/AP ratio, and Identify the scale of the mixing that will prevent Acid Rock Drainage from the Jay Waste Rock Storage Area. This Design is to be in accordance with Schedule 6, Condition 4.” The results of the co-placement study will be outlined in the Jay Amendment to the Waste Rock and Ore Storage Management Plan [WROMP] (Schedule 6, Condition 2(x) of the Water Licence amendment, which will be submitted to the WLWB for approval minimum of 90 days prior to Construction of the Jay pit. The Co-Placement Study Design addresses the following three key areas of perceived uncertainty:

1) geochemical criteria for co-placement, namely the target ratio of neutralization potential for acid potential (NP/AP ratio) for co-placement;

2) design and operation of the Jay WRSA; and,

3) co-placement methods to achieve the target NP/AP ratio.

On approval of the study design by the WLWB, the study will initiate on a timeline that is amenable to the schedule for the Jay amendment to the WROMP for the Ekati mine. Should you have any questions related to our suggested approach please contact the undersigned at [email protected] or 867-445-1510 or Lukas Novy, Team Leader –LOM Planning at [email protected] or 867-446-8362. Sincerely,

April Hayward PhD, Superintendent Environment

Violet Camsell-Blondin- Chair Wek’èezhìi Land and Water Board #1, 4905 – 48th Street Yellowknife, NT, X1A 3S3

WASTE ROCK STORAGE AREA CO-PLACEMENT STUDY DESIGN

FOR THE JAY PROJECT

Prepared for: Dominion Diamond Ekati Corporation Prepared by: Golder Associates Ltd.

October 4, 2017

Waste Rock Storage Area Co-Placement Study DesignJay Project

Table of Contents October 4, 2017

i

Table of Contents

1 INTRODUCTION AND BACKGROUND ............................................................................................. 1-1 1.1 Background ................................................................................................................................... 1-1

2 REGULATORY REQUIREMENTS ..................................................................................................... 2-1

3 GEOCHEMICAL CHARACTERISTICS OF JAY WASTE ROCK ...................................................... 3-1

4 OVERVIEW OF ENVIRONMENTAL PROTECTION MECHANISMS IN THE JAY WASTE ROCK STORAGE AREA DESIGN ..................................................................................................... 4-1

5 STUDY DESIGN .................................................................................................................................. 5-1 5.1 Geochemical Testing .................................................................................................................... 5-1 5.1.1 Sample Collection ...................................................................................................................... 5-4 5.1.2 Phase I – Material Characterization ........................................................................................... 5-4 5.1.3 Phase II – Detailed Mineralogical Analysis ................................................................................ 5-5 5.1.4 Phase III – Laboratory Leach Testing ........................................................................................ 5-6 5.1.5 Phase IV - Future Geochemical Testing .................................................................................... 5-7 5.2 Waste Rock Placement Optimization and Monitoring During Mining ........................................... 5-8 5.2.1 Waste Rock Placement Optimization ........................................................................................ 5-8 5.2.2 Neutralization Potential to Acid Generating Potential (NA/NP) Monitoring ............................... 5-9 5.3 Misery Waste Rock Storage Area Monitoring Program ................................................................ 5-9

6 REPORTING ....................................................................................................................................... 6-1

7 CLOSURE ........................................................................................................................................... 8-1

8 REFERENCES .................................................................................................................................... 9-1


Table of Contents October 4, 2017

ii

Figures

Figure 3-1 Neutralization Potential to Acid Generating Potential (NP/AP) Ratio of Samples in the Ekati Mine Geochemistry Dataset .............................................................................. 3-3

Figure 3-2 pH, Sulphate, and Alkalinity Trends in Humidity Cell Testing Leachates ........................ 3-6 Figure 3-3 Comparison of Final Humidity Cell Test pH and Total Sulphur Content of

Humidity Cell Test Samples ............................................................................................. 3-7 Figure 4-1 Annual Waste Rock Production Schedule (Interim October 2015 Mine Plan). ............... 4-2 Figure 4-2 Predicted Annual Neutralization Potential to Acid Generating Potential (NP/AP)

Ratio of Co-Placement Zone, Assuming Interim October 2015 Mine Plan ...................... 4-3 Figure 5-1 Overview of Main Components of the Laboratory Geochemical Testing Program

for the Co-placement Study Design ................................................................................. 5-3 Figure 5-2 Comparison of Co-Placement Methods ........................................................................... 5-8

Appendices

Appendix A Conformance Table for Co-Placement Study Design


Abbreviations and Units of Measure October 4, 2017

iii

Abbreviations


ABA acid base accounting

AP acid generation potential

ARD acid rock drainage

CaCO3 calcium carbonate

DDEC Dominion Diamond Ekati Corporation

Ekati mine Ekati Diamond Mine

EPMA Electron Microprobe Analysis

Golder Golder Associates Ltd.

HCT humidity cell testing

MEND Mine Environment Neutral Drainage

ML metal leaching

NAG net acid generation

non-PAG non-potentially acid generating

NP neutralization potential

PAG potentially acid generating

Project Jay Project

QEMSCAN Quantitative Evaluation of Materials by Scanning Electron Microscopy

ROM run-of-mine

WLWB Wek'èezhı̀ı Land and Water Board

WROMP Waste Rock and Ore Storage Management Plan

WRSA waste rock storage area

Units of Measure

Unit Definition

% percent

< less than

> greater than

°C degrees Celsius

cm centimetre

kg kilogram

kg CaCO3/t kilograms of calcium carbonate equivalent per tonne of material

km kilometre

m metre

mg/L milligrams per litre

mm millimetre

wt% weight percent


Section 1, Introduction and Background October 4, 2017

1-1

1 INTRODUCTION AND BACKGROUND The Ekati Diamond Mine (Ekati mine), owned by Dominion Diamond Ekati Corporation (DDEC), received Ministerial Approval of a Type A Water Licence Amendment (Water Licence amendment) for the Jay Development on July 6, 2017. The Wek'èezhı̀ı Land and Water Board (WLWB) submitted a decision letter with the Water Licence Amendment, outlining concerns with respect to the proposed Jay waste rock storage area (WRSA), in particular related to areas of uncertainty associated with design and operational aspects of the Jay WRSA. In response, the WLWB required that a Co-Placement Study Design (co-placement study) be submitted to the Board for approval within 90 days of the effective date of the Water Licence amendment (Part H, Condition 4).

The overall objective of the co-placement study design outlined in Part H, Condition 4 of the Water Licence amendment is “to optimize the co-placement strategy, determine the target NP/AP ratio and identify the scale of mixing that will prevent Acid Rock Drainage from the Jay Waste Rock Storage Area”. The minimum guidelines for the investigation are defined in Schedule 6, Condition 3 of the Water Licence amendment. The results of the co-placement study must be outlined in the Jay Amendment to the Waste Rock and Ore Storage Management Plan [WROMP] (Schedule 6, Condition 2(x) of the Water Licence amendment), which will be submitted to the WLWB for approval

The co-placement study outlined in this document addresses the key areas of uncertainty articulated in the WLWB decision letter, and meets the aforementioned minimum investigation guidelines. Necessary background information related to the regulatory requirements for the study, the geochemical characteristics of Jay waste rock, and the Jay WRSA design are summarized in this document for context. The study design has been developed to make use of existing materials (e.g., waste rock from nearby, geologically analogous Misery Pit) and existing site-specific monitoring data (e.g., seepage monitoring data from the Misery WRSA) to develop a dataset that can be used to refine the Jay WRSA design in a timeline amenable to development of the Jay Pit. The study design consists of a comprehensive mineralogical and leach testing study to be completed in the short term (i.e., in advance of mining at the Jay Pit) using waste rock from the Misery Pit. Future study components include testing of waste rock produced during the early stages of mining at the Jay Pit, and investigation of the Misery WRSA after the completion of mining at the Misery Pit. A schedule, including commitments related to reporting and WLWB feedback with respect to key study milestones, is provided, which will facilitate timely and iterative feedback from the various stakeholders to advance of the Jay Development.

1.1 Background The Jay Waste Rock Storage Area Design Report (Golder 2016) provides the rationale for co-placement of metasedimentary rock with granite and diabase in the Jay WRSA: “Metasediment from the Jay Pit will be co-placed with non-potentially acid generating (non-PAG) granite and diabase waste rock. The purpose of co-placement of potentially acid generating (PAG) and non-PAG rock is to mitigate the acid generation potential of PAG rock by minimizing the potential for formation of extensive PAG rock zones within the Jay WRSA.” The Jay WRSA design formed the basis of the conceptual model for water quality predictions for the Environmental Assessment for the Jay Project (Project). The Mackenzie Valley Environmental Impact Review Board concluded that co-placement, in combination with other mitigative commitments, would likely result in seepage water quality from the Jay WRSA that is suitable for release to the environment.


Section 1, Introduction and Background October 4, 2017

1-2

In the decision letter issued with the Water Licence amendment submitted for Ministerial Approval, the WLWB “agrees with DDEC that co-placement is a reasonable means of reducing the risks of long-term acid rock drainage (ARD) and metal leaching (ML) from the Jay WRSA”. However, the WLWB outlined uncertainties with respect to the design and operational aspects of the proposed Jay WRSA design, citing lack of evidence of efficacy of co-placement to mitigate ARD / ML potential at other mines. The WLWB required a co-placement study to address these uncertainties as a component of the Ekati Jay Development Water License Amendment (W2012L2-0001 Amendment #4, Part H Condition 4).

Based on the review of the decision letter and the Water License Amendment, the three main areas of uncertainty to be addressed by the co-placement study are:

1) geochemical criteria for co-placement, namely the target ratio of neutralization potential for acid potential (NP/AP ratio) for co-placement;

2) design and operation of the Jay WRSA; and,

3) co-placement methods to achieve the target NP/AP ratio.

As stated in the decision letter, the WLWB “expects DDEC to address several outstanding issues related to the Study Design that were raised during the proceeding. These include the need for a field component, the use of humidity cell tests, and whether Jay or Misery rock will be used for various components of the study. The Board will consider a final decision on these aspects following public review of the Study Design.”

The results of the co-placement study will be used to optimize the design, operation and co-placement methods in the Jay WRSA. The placement methods, limits, and controls will be described in the Jay Amendment to the WROMP (Schedule 6, Condition 2(x)).


Section 2, Regulatory Requirements October 4, 2017

2-1

2 REGULATORY REQUIREMENTS The Co-Placement Study Design requirements are outlined in Schedule 6, Condition 3 of the draft Water Licence amendment:

Schedule 6, Condition 3

“The study outlined in the Jay Waste Rock Co-placement Study Design, referred to in Part H, Condition 4, shall investigate at minimum the following:

a) the sensitivity of effective neutralizing potential/acid potential (NP/AP) to imperfect mixing for the propose co-placement management plan;

b) whether the effective neutralizing potential/acid potential (NP/AP) characteristics of the fine rock fractions for metasediments, granite, and diabase are different in samples of rock blasted during mining, than in samples of rock prepared for humidity cell testing, and if so, a means of accounting for the differences when managing the proposed co-placement of rock in the WRSA;.

c) how to optimize co-placement methods of blending and layering for the proposed co-placement of the potentially acid generating (PAG) and non-PAG rock to prevent acid rock drainage and metal leaching; and

d) any other testing or analysis that will inform the most appropriate NP/AP ratio and the co-placement method, limits, and controls for blending and/or layering.”

In addition, several parts of Schedule 6, Condition 2 (WROMP) require consideration in the context of the Co-Placement Study Design:

Schedule 6, Condition 2

“Acid Rock Drainage (ARD) Characterization

g) For the Jay Waste Rock Storage Area, identification of the “effective” neutralization potential (NP) in Waste Rock as defined by Mine Environment Neutral Drainage’s Prediction Manual for Drainage Chemistry from Sulphidic Geologic Materials, December 2009;

h) For the Jay Waste Rock Storage Area, the proposed target neutralization potential to acid potential (NP/AP) ratio for bulk rock in the Jay Waste Rock Storage Area, with a detailed rationale that addresses the effective NP, the results of the Geochemistry Baseline Report and the results of the Waste Rock Co-placement Study referred to in Part H, Condition 4;

Waste Rock and Ore Storage Management

o) Temperature analysis of all Waste Rock Storage Areas having acid/alkaline potential to include the effect of oxidation reactions on predicted Acid/Alkaline Rock Drainage generation rates;

r) A description of co-placement method, limits, and controls for blending and layering;


Section 2, Regulatory Requirements October 4, 2017

2-2

s) A description of confirmatory sampling and field inspection program to verify co-placement;

t) A description of Waste Rock sampling within the Jay open pit to confirm geochemical characteristics;

x) Discussion of how the results of the Study conducted in accordance with the approved Jay Waste Rock Co-placement Study Design referred to in Part H, Condition 4 were considered in the proposed Waste Rock and ore management;”

The tasks outlined in Schedule 6, Condition 2 of the Water License Amendment were considered in the development of this study design. The information generated by this co-placement study can be used to support the Water Licence requirements for the WROMP.

Appendix A summarizes the Co-Placement Study Design requirements and identifies which section of this document addresses each requirement.


Section 3, Geochemical Characteristics of Jay Waste Rock October 4, 2017

3-1

3 GEOCHEMICAL CHARACTERISTICS OF JAY WASTE ROCK

The Project is located approximately 25 kilometres (km) from the main facilities at the Ekati mine and approximately 7 km northeast of the existing Misery Pit, beneath Lac du Sauvage in the Lac de Gras watershed. The Jay kimberlite pipe has similar geological characteristics as the nearby Misery Pit. The three principal rock types at the Project identified by geological logging are granite (two mica granite and tonalite), metasediment and diabase. Granitic rocks host the kimberlite pipe. A regional contact with metasedimentary rocks occurs to the west, and a diabase dyke trending approximately east-west occurs to the north of the pipe. The Jay pipe is then overlain by 5 to 10 metres (m) of overburden, and up to 35 m of water in Lac du Sauvage.

The geochemical dataset for the Ekati mine is extensive, consisting of over 3,000 samples collected between 1995 and 2014 (DDEC 2014). Static testing results, namely acid base accounting (ABA), mineralogical analysis, and bulk metal analysis, were used to determine the solid phase characteristics of the four main rock types at the Ekati mine. The ABA results were used to determine the acid generation potential (AP) and neutralization potential (NP) of each rock type. Mineralogy results were used to confirm the mineralogical sources of AP and NP, as well as potential metal sources in waste rock. The bulk metals analyses were then used to qualitatively identify parameters that may require further evaluation of leaching potential. Static testing was conducted on samples of exploration drill core collected prior to mining at each open pit, and samples of blasted waste rock as part of the confirmation testing program conducted as a component of the WROMP. A subset of samples of each rock type was submitted for kinetic testing (i.e., humidity cell testing [HCT]) to confirm the effects of weathering of waste rock in laboratory conditions. Kinetic tests were conducted on samples of exploration drill core. The kinetic testing results were interpreted in the context of the ABA data to calculate total sulphur and NP depletion rates, based on the rate of production of sulphate and alkalinity in HCT leachates. Depletion rate calculations are used to predict the time to onset of acid generation in laboratory conditions, which can be used to approximate field-scale conditions.

The principal geochemical sample collection effort for the Project took place in 2014, including 30 samples of granite, 24 metasediment, 4 diabase and 2 kimberlite that were submitted for ABA, net acid generation (NAG) testing, trace metals analysis, mineralogical analysis and short-term leach testing. The results of Jay waste rock sample analysis were interpreted in the context of overall geochemical test results for the Ekati mine.

Granite generally consists of felsic, silicate minerals including quartz, plagioclase, feldspar, biotite, chlorite, kaolinite and ilmenite, with trace carbonate, epidote, magnetite, apatite and pyrite. Acid base accounting results confirmed that granite has a low sulphide mineral content. Total sulphur concentrations in granite range from 0.001 to 0.42 weight % (wt%) (1,229 samples), with a median concentration of 0.02 wt% and an average concentration of 0.03 wt%. The bulk NP of granite samples ranges from 0.8 to 331 kg CaCO3/t (470 samples), with a median of 5.0 kg CaCO3/t and average of 8.9 kg CaCO3/t. Figure 3-1 presents the acid generation potential of granite, defined using the NP/AP ratio according to the MEND (2009) guidelines. Samples with an NP/AP ratio greater than 2 are considered non-PAG, and samples with an NP/AP ratio less than 1 are classified as PAG. Samples with an NP/AP ratio between 1 and 2 have an “uncertain” potential for acid generation: these samples could generated acidity if NP is insufficiently reactive, or depletes at a rate faster than sulphide minerals. The NP/AP ratio ranges from



3-2

0.3 to 496 (470 samples), with a median value of 8.0 and an average value of 8.4. In total, 95% of the samples in the granite dataset (446 of 470 samples) had an NP/AP greater than 2, and were classified as non-PAG. The remaining 24 samples had an NP/AP ratio less than 2, of which 18 samples (4% of the overall dataset) were designated as having an uncertain acid generation potential, and the remaining six samples (1% of the overall dataset) were classified as PAG, with an NP/AP ratio less than 1.



3-3

Figure 3-1 Neutralization Potential to Acid Generating Potential (NP/AP) Ratio of Samples in the Ekati Mine Geochemistry Dataset



3-4

Similarly, diabase has a low potential for acid generation. One sample of diabase in the dataset underwent mineralogical testing, in which only silicate minerals were identified (plagioclase feldspar, augite, illite, ilmenite, kaolinite, phlogopite, and quartz). Diabase samples have a low total sulphur content, ranging from <0.005% to 1.3% (average of 0.13% and median of 0.09%). The bulk NP of diabase ranges from 0.5 to 68 kg/t CaCO3, with an average value of 13 kg/t CaCO3 and a median value of 11 kg/t CaCO3. The NP/AP ratio of diabase samples collected from the Ekati mine ranges from 0.04 to 60, with an average of 3.3 and a median of 3.8. In total, 92% of the diabase dataset (79 of 86 samples) consisted of non-PAG samples (NP/AP ratios >2), 5% (4 of 86 samples) had an uncertain acid generation potential (NP/AP ratios between 1 and 2), and 3% (3 of 86 samples) was classified as PAG (NP/AP<1).

Minerals present in metasedimentary rock include quartz, chlorite, amphibole, phlogopite, illite, feldspar, calcite, dolomite, siderite, and kaolinite, with trace pyrite and pyrrhotite. The total sulphur content of metasediment samples ranges from <0.005 to 1.0 wt% (average 0.16 wt% and median 0.16 wt%). Bulk NP varies between 0.1 to 406 kg/t CaCO3 (average 17 kg/t CaCO3 and median 9 kg/t CaCO3). Overall, NP/AP ratios range from 0.3 to 39 (average 3.3 and median 1.8). In total, 50% of the samples in the metasediment dataset (224 of 453 samples) were classified as non-PAG (NP/AP <2). In the remaining 50% of the samples, 38% had an uncertain acid generation potential (NP/AP between 1 and 2), and 12% were designated PAG (NP/AP <1). A substantial portion (50%) of the metasediment samples in the Ekati dataset are classified as uncertain and PAG and, because this subset of metasediment cannot be readily identified and separated in the field, all metasediment has been operationally classified as PAG for the purpose of material management at the Mine.

The calculation of the NP/AP ratio assumes that all NP is “effective”, and available for reaction. Effective NP is the buffering capacity of a sample that can neutralize acidity to maintain, at a minimum, a near neutral pH (approximately 6). The effectiveness of the NP to mitigate acid generation potential is a function of several factors, including carbonate mineralogy, textural characteristics (e.g., degree of liberation), and the weathering rates of NP in site conditions (MEND 2009). Ultimately, the influence of site-specific conditions on effective NP will be further investigated by a detailed leach testing program, described in Section 5.1.

Iron or manganese-bearing carbonates, such as siderite and rhodochrosite, are not net-neutralizing, as hydrolysis reactions that occur in conjunction with the carbonate dissolution consume alkalinity. The results of mineralogical analysis of granite confirmed that only trace amounts of carbonate are present, and no iron or manganese carbonate minerals were identified. The primary mineralogical source of NP in granite, diabase and metasediment are silicate minerals, which release alkalinity by reaction with atmospheric carbon dioxide. Silicate mineral weathering rates are slow in the cold, arid site conditions, which controls the effective NP of these minerals.

The geochemical testing dataset consists of samples of exploration drill core and waste rock collected from waste rock stockpiles, which underwent grain size reduction (crushing and grinding) prior to laboratory analysis. This completely liberates mineralogical sources of AP and NP as the grain size reduction increases the mineral surface area and optimizes reactivity. Therefore, minerals capable of contributing to the AP and NP may not have the same surface area exposure or grain size distribution in crushed laboratory samples as in blasted rock, which can affect the effective NP of waste rock in site conditions relative to laboratory results. Despite these limitations, it should be noted that HCT results are commonly used as an analogue for the geochemical behaviour of material in WRSAs. HCTs are



3-5

conducted using samples that are either crushed or screened to pass a 6.3-millimeter (mm) (or 0.25-inch) screen. Morin and Hutt (1997) suggest that HCT results are generally a reasonable direct analogue for mine facilities (such as waste rock dumps). Although waste rock dumps contain much coarser material, their total surface area (and thus their reactivity) is dominated by their fines content, which is the fraction represented in a humidity cell. Therefore, HCT results can be considered a reasonable approximation for the “effective” NP of a material in accelerated leaching conditions.

Humidity cell tests were conducted on 13 samples of granite, and six samples of diabase. In the granite and diabase dataset, 14 samples had NP/AP ratios greater than 2, two samples had NP/AP ratios between 1 and 2 (uncertain acid generation potential) and one sample had an NP/AP ratio less than 1 (PAG). For two samples the NP values had not been determined, so it was not possible to calculate an NP/AP ratio. Non-PAG HCT samples had a total sulphur content from <0.005 to 0.12 wt% (median 0.02 wt%), the two uncertain samples contained 0.05 and 0.08 wt% total sulphur, respectively, and the PAG diabase sample (Fox Pit) contained 0.43 wt% total sulphur. The two granite samples with an unknown NP contained 0.12 and 0.19 wt% total sulphur. The NP of the non-PAG granite and diabase samples was slightly higher (1 to 15 kg/t CaCO3) than the uncertain and PAG samples (0.5 to 3.1 kg/t CaCO3). Figure 3-2 presents HCT results for pH, sulphate and alkalinity. Of the three granite and diabase samples that had NP/AP ratios less than 2, only one sample (diabase; 0.43 wt% total sulphur, which is the highest total sulphur content in the granite / diabase dataset) generated acidic conditions during the HCT (Figure 3-3). As shown in Figure 3-3, samples containing less than approximately 0.15 wt% total sulphur did not produce acidic conditions during the HCT program.



3-6

Figure 3-2 pH, Sulphate, and Alkalinity Trends in Humidity Cell Testing Leachates

CaCO3 = calcium carbonate; mg/L = milligrams per litre; NP/AP = neutralization potential/acid potential.



3-7

Figure 3-3 Comparison of Final Humidity Cell Test pH and Total Sulphur Content of Humidity Cell Test Samples

wt% = weight percent; NP/AP = neutralization potential/acid potential.

Eleven metasediment samples underwent HCT, of which six samples had NP/AP ratios between 1 and 2, and three samples had NP/AP ratios greater than 2. For two samples the NP values were not determined, and NP/AP was not calculated. The total sulphur content of the metasediment HCT samples ranged from 0.1 to 0.43 wt%, and NP from 5.6 to 22 kg/t CaCO3. Two of the three samples with NP/AP greater than 2 maintained long-term neutral pH values in the metasediment HCT, and one sample reported an acidic long-term pH. All PAG HCTs generated acidic conditions during the test. As shown in Figure 3-3, all metasediment samples that generated acidic HCT leachates had total sulphur concentrations greater than approximately 0.15 wt%.

The long-term potential for acid generation in granite, diabase and metasediment HCTs was predicted by comparing sulphate and alkalinity production rates to initial solid phase concentrations of total sulphur and NP. Samples from which NP was predicted to deplete prior to total sulphur were classified as PAG, and vice versa. Total sulphur and NP depletion calculations were performed using the calculation for empirical rate of NP consumption in an open system at pH 6, which accounts for long-term sulphate,



3-8

alkalinity and acidity production rates in an HCT (MEND 2009). The calculations were also performed assuming the theoretical NP production at pH 6, which is based solely on sulphate production rates (MEND 2009). Sample classification according to NP/AP ratio was compared to the depletion rate calculations to determine if the NP/AP ratio appropriately classifies materials based on mineral reaction rates:

NP/AP < 1: Only one diabase HCT sample was designated PAG based on the ABA results; for this sample, both depletion rate calculation methods confirmed its long-term PAG character.

NP/AP between 1 and 2: Seven of 8 samples with an NP/AP ratio between 1 and 2 were classified as non-PAG using both depletion rate calculation methods. One sample (HC-4 (Sable, biotite granite / schist)) had an NP/AP ratio of 1.1 and a total sulphur content of 0.08 wt%. NP was predicted to deplete prior to AP in this sample using the first method (accounting for sulphate, alkalinity and acidity). Using the sulphate production method, sulphur was predicted to deplete from this sample prior to NP.

NP/AP > 2: For all but four of the samples designated non-PAG by ABA, both depletion rate calculation methods confirmed their long-term non-PAG character.

o Using the first method, which accounts for sulphate, alkalinity and acidity, NP was predicted to deplete prior to AP from four non-PAG HCTs (F4-1 188 (Fox, granite), KDC-03-480 (Koala, granite), HC-2 (Sable, two-mica granite / pegmatite), and HC-2 (Beartooth, granite)). The total sulphur content of these samples ranged from 0.04 to 0.12 wt%, and NP/AP ratios from 2 to 8.8. Long-term sulphate production concentrations were low and stable in all four samples (less than 10 mg/L). The outcome of the depletion rate calculation was driven by long-term alkalinity production rates; these samples maintained long-term alkalinity concentrations greater than 20 mg/L as CaCO3, which were higher than any others in the granite and metasediment datasets. Using the second (i.e., sulphate production) method for calculating NP depletion, sulphur was predicted to deplete from these samples prior to NP. Despite these apparent contradictory results, these four samples are considered to present a minimal risk for long-term acid generation, given their low total sulphur concentrations and low rates of sulphate production, which are anticipated to be even lower in site conditions.

As discussed in Section 5.1.4, the influence of site-specific conditions on effective NP in low-sulphur samples will be further investigated by a detailed leach testing program.

The results of the laboratory geochemical testing are supplemented by long-term monitoring data (2001 to present) from the Misery WRSA, which represent the site-specific reactivity of layered granite and metasedimentary rock. The existing Misery WRSA can be considered a reliable field analogue for the Jay WRSA. Seepage monitoring results from the Misery WRSA reflect the effective neutralization potential of waste rock in site-specific conditions. Based on the monitoring results, it is evident that the reaction rates of granite / diabase to date have been sufficient to neutralize acidity generated by oxidation of metasediment over the approximate 15 year history of the Misery WRSA, even with the lesser proportion of granite in the Misery WRSA (as compared to the proposed proportion for the Jay WRSA). Seepage from the Misery WRSA has a median pH of 6 (95th percentile pH of 4.8, which is similar to the pH of nearby tundra), and a median sulphate concentration of 35 milligrams per litre (mg/L) (95th percentile concentration of 150 mg/L). Sulphate and metal concentrations are elevated in Misery WRSA seepage



3-9

relative to surface water from the Bearclaw Lake and Sable Lake reference areas, indicating that sulphide oxidation is occurring within the pile. Sustained, low-pH drainage conditions are not being realized because the acidity is being neutralized by the reaction of granite / diabase in the WRSA. The Misery WRSA will be closed upon completion of the closure cover, at which time a geochemical and geothermal investigation is proposed to gather information that will enhance predictions of the performance of the Jay WRSA (Section 5.3).


Section 4, Overview of Environmental Protection Mechanisms in the Jay Waste Rock Storage Area Design

October 4, 2017

4-1

4 OVERVIEW OF ENVIRONMENTAL PROTECTION MECHANISMS IN THE JAY WASTE ROCK STORAGE AREA DESIGN

The Jay WRSA design was developed to achieve the key objectives for WRSA design and construction at the Ekati mine, as outlined in the Ekati Diamond Mine Waste Rock and Ore Storage Management Plan (WROMP) Version 6.1 (DDEC 2016), as follows:

to be inherently, physically, and geochemically stable structures, both during mine operations and in the long term;

to be permanent structures that will remain in place following the completion of mining;

to promote permafrost aggradation;

to achieve a reasonable balance between surface footprint area and height, with a target height of 50 m; and,

to minimize runoff and encourage permafrost formation.

Using the objectives outlined above, the Jay WRSA was designed using the interim October 2015 mine plan. The pile has a 2-m basal layer of non-PAG rock over the tundra and / or stored overburden materials to promote early aggradation of permafrost into the base of the WRSA and to limit contact of potentially reactive waste rock over tundra soils, which can be naturally acidic. A 5-m cover will be placed over the top and sides of the WRSA during construction, to maintain the active layer within the non-PAG granite cover. Non-PAG and PAG waste rock will be co-placed within a central zone which will be encapsulated by the non-PAG granite cover. Co-placement of Jay Pit waste rock on an “as-mined” basis during operations is possible because of the simultaneous production of metasediment, diabase, and granite (with a predominance of granite) throughout the mine life (Figure 4-1).



October 4, 2017

4-2

Figure 4-1 Annual Waste Rock Production Schedule (Interim October 2015 Mine Plan)

The 5-m granite cover will be progressively placed as portions of the co-placement zone of the pile are completed. The granite cover around the perimeter of the storage area will be placed in horizontal lifts around the co-placed materials to obtain the final benched WRSA geometry with maximum 3H:1V overall slopes. This construction method allows for progressive closure of areas of the WRSA, and minimizes the amount of time the co-placement zone is exposed.

The intent of the design is that the pile will freeze to sub-zero temperatures beneath the surficial active layer. The 5-m granite cover layer is designed to maintain PAG materials within the pile in permafrost conditions in the WRSA, which is a general design objective for Ekati mine WRSAs and the approved standard for WRSAs at the Ekati mine. Thermal modelling results for the proposed WRSA design (which considered climate change conditions) indicated an active layer thickness of less than 5 m (Golder 2016).

Regardless, the closure performance of the Jay WRSA is not reliant on the 5-m granite cover because the WRSA has been designed to be geochemically stable even in thawed conditions. The proposed co-placement of metasedimentary rock with granite and diabase is designed to mitigate the acid generation potential of the waste rock. In general, an excess of granite and diabase rock will occur during all stages of the mine life, particularly in the last three years of production when no metasediment will be produced (Figure 4-1). The mine plan will be optimized to achieve simultaneous production of granite and metasediment for construction of the co-placement zone. As outlined in Section 3, the median sulphur content of granite and diabase is low. Likewise, although a fraction of metasediment is PAG, 50% of the samples in the metasediment dataset were classified as non-PAG. The acid generation potential of metasediment is driven by a combination of sulphur content and low NP content. As discussed in Section 3, the presence of carbonate NP in metasediment is minimal; most NP is contributed by silicate mineral phases. Given the low rates of reaction in the cold, site conditions and overall low sulphur concentrations in Ekati mine waste rock, the silicate NP is considered sufficient to mitigate the acidity



October 4, 2017

4-3

generated by sulphide oxidation, as evidenced by seepage water quality monitoring results at the nearby Misery WRSA.

Based on conservative mass balance calculations performed using the interim mine plan, the annual NP/AP ratio of the co-placement zone ranges from approximately 2.5 in the early years of mining to 14 toward the end of the mine life (Figure 4-2). The predicted NP/AP ratio of the co-placement zone is conservative by assuming that only a fraction of the granite produced every year will be placed in the co-placement zone to maintain an NP/AP ratio greater than 2, with the remainder used for construction of the outer berms and granite cover. In fact, additional granite may be placed into the co-placement zone, which would further increase the NP/AP ratio of the co-placement zone. Furthermore, it also conservatively assumes that all AP (i.e. sulphur minerals) and NP (i.e. silicate and carbonate minerals) will be exposed, and available for reaction. The overall NP/AP ratio of the entire WRSA at the end of Jay operations, inclusive of all granite to be mined, is projected to be 4.3.

Figure 4-2 Predicted Annual Neutralization Potential to Acid Generating Potential (NP/AP) Ratio of Co-Placement Zone, Assuming Interim October 2015 Mine Plan

As discussed in Section 3.0, the long-term geochemical tests conducted in laboratory conditions indicate that waste rock samples with an NP/AP ratio greater than 2 did not generate acidity during the tests. These tests took place over a period of 38 to 133 weeks, which equates to approximately 7 to 25 years in field conditions if HCTs accelerate reactivity by approximately one order of magnitude This acceleration is due to the reduced grain size, leaching conditions (i.e. enhanced water to rock contact) and temperature differences (i.e. room temperature versus colder site temperatures).

Therefore, the existing kinetic testing results are considered to provide an upper boundary on the long-term reactivity of individual, un-mixed samples of metasediment, granite and diabase. In a field setting, co-placement of granite/diabase with metasedimentary rock should provide sufficient NP to neutralize any acidity generated by sulphide oxidation during operations, prior to complete freezing of the pile. The



October 4, 2017

4-4

existing climate conditions at the site and eventual aggradation of permafrost into the pile are expected to reduce chemical weathering rates in the Jay WRSA relative to laboratory conditions.

In summary, several environmentally protective measures were incorporated into the Jay WRSA design. Co-placement of waste rock will “dilute” the acid generation potential of PAG metasedimentary rock. The co-placement zone will be encapsulated within the internal zone of the WRSA, which will be progressively covered with a minimum 5-m layer thick granite cover. The active zone will be maintained within the granite cover, which will ultimately limit infiltration into the co-placement zone. Lastly, aggradation of permafrost will be promoted by the construction method, leading to ultimate freezing of the co-placement zone.


Section 5, Study Design October 4, 2017

5-1

5 STUDY DESIGN The proposed study has been designed to address the following key questions, derived from Schedule 6, Condition 3 of the Water License:

1. What is the effective NP of mixed PAG and non-PAG blasted waste rock?

2. What is the cut-off criterion to ensure a blend will maintain non-PAG characteristics in long-term?

3. How will the material be placed to achieve the target blend ratio?

The study consists of three components, which will be conducted as follows:

Geochemical testing will be initiated using waste rock from the nearby Misery Pit as soon as possible. This geochemical testing program will be supplemented with samples from the Jay Pit when mining commences.

A waste rock placement and monitoring system will be developed using the existing Wenco technology utilized by site operations.

A geochemical and geothermal monitoring program is proposed for the Misery WRSA on completion of the WRSA closure cover to evaluate the site-specific geochemical reactivity of co-placed granite and metasediment.

5.1 Geochemical Testing A laboratory-scale geochemical testing program will be undertaken to determine the effective NP of blasted waste rock from the Ekati mine, in response to the following components of Schedule 6, Condition 3 of the water license:


b) whether the effective neutralizing potential/acid potential (NP/AP) characteristics of the fine rock fractions for metasediments, granite, and diabase are different in samples of rock blasted during mining, than in samples of rock prepared for humidity cell testing, and if so, a means of accounting for the differences when managing the proposed co-placement of rock in the WRSA;

d) any other testing or analysis that will inform the most appropriate NP/AP ratio and the co-placement method, limits, and controls for blending and/or layering.”

The geochemical testing program has been designed to determine the effective NP as defined by MEND (2009):

Effective NP = Measured NP – (nnNP + UNP + IRNP) + LSNP



5-2

Where:

1) nnNP: minerals that are not net neutralizing that contribute to measured NP 2) UNP = Unavailable NP: the mineralogical portion of NP that is physically occluded in field-scale,

site conditions 3) IRNP = Insufficiently reactive NP: NP that is kinetically unable to neutralize acidity at field rates 4) LSNP = Long-term, slowly reacting NP: NP that is kinetically limited by reaction rates, but is

able to sufficiently neutralize acidity in field conditions

Figure 5-1 outlines the main components of the laboratory geochemical testing program.



5-3

Figure 5-1 Overview of Main Components of the Laboratory Geochemical Testing Program for the Co-placement Study Design



5-4

5.1.1 Sample Collection The geochemical testing program will be conducted on samples of blasted waste rock, in order to determine the distribution of AP and effective NP in the grain size fractions represented in run-of-mine (ROM) rock. Waste rock will not be produced from the Jay Pit in a timeframe amenable to this study. Therefore, it is proposed that waste rock be collected from the Misery Pit, which is geologically analogous to the nearby Jay Pit. Metasedimentary rock is currently being mined from the Misery Pit; it is anticipated that mining of the Misery Pit will be completed in early 2018; metasedimentary rock will be covered in the final Misery WRSA configuration. Therefore, sample collection will take place prior to the approval of the co-placement study design, in order to ensure availability of sufficient material to conduct subsequent phases of geochemical testing.

Waste rock samples will be collected under the supervision of a Professional Geologist of the Northwest Territories, specializing in environmental geochemistry. Samples will be collected from ROM rock that has been recently deposited waste rock in the Misery WRSA (granite and metasediment), and blast rock from the Lynx open pit (diabase).

Ten sample locations will be determined for metasediment, granite and diabase.. The approach to sample collection will depend on the availability of suitable material from either ROM or the Misery WRSA. Safety issues will be an important consideration. An excavator will be used to segregate material for sampling, by moving a small amount of ROM rock to a staging area for visual inspection and sub-sampling. At each sample site, the material will be photographed and visually logged with respect to lithology, mineralogy and grain size distribution.

Next, several sub-samples will be collected from each sample site for the purpose of geochemical testing. These samples are referred to as the “bucket samples”. Each bucket sample will consist approximately 35 kilograms (kg) of rock that will be stored in a sealed, 5-gallon rock pail. Six bucket samples will be collected at each location, to allow for sufficient material for future laboratory testing, resulting in 60 bucket samples, depending on the number of sample locations. Each bucket sample will be assigned a unique sample ID. The grain size of the material collected for the bucket samples will range from the very fine fraction (silt to sand sized) to the gravel sized fraction (less than approximately 20 centimetres [cm]).

The characteristics of each bucket sample must be confirmed prior to their potential use in the leach testing program. When the bucket samples are received by the analytical laboratory, the laboratory will homogenize the material in the bucket and split a 1 kilogram (kg) representative sub-sample for analysis. The laboratory sample will be assigned the same sample ID as the pail. Analysis of laboratory samples is described in Section 5.1.2 (Phase I – Material Characterization). The bucket samples will be sealed, and stored in a safe, cold conditions at the analytical laboratory until required for future testing. Field observations and the sample collection effort will be described in the co-placement study report.

5.1.2 Phase I – Material Characterization The objective of the laboratory testing program is to identify and describe the characteristics of the effective NP in waste rock. Thorough investigation of the chemical and mineralogical composition of each sub-sample is required in order to design and construct the leach testing program in an informed manner.

Grain size analysis will be conducted on each sample to determine the grain size distribution of material that will be used in any further testing. These results will be compared to historical blasting information,



5-5

and grain size observations from the Beartooth and Fox WRSAs. This information will be interpreted in the context of the mineralogical results to determine the distribution of effective NP in the various grain size fraction present in the ROM rock. This information is also required in the eventual interpretation of the leach test results.

Solid phase chemical analysis is required to compare the compositional range of ROM rock to the existing geochemical dataset for the Ekati mine. All samples will be submitted for total metals analysis (aqua regia digest with ICP-MS finish) and ABA (paste pH, sulphur species (including total sulphur, sulfate sulphur, and sulphide sulphur), bulk NP, total carbon and carbonate). NAG testing will be performed to confirm the acid generation potential of ROM samples that have been classified as PAG or “uncertain” according to the results of ABA. Net acid generation testing is typically performed on samples of rock that have undergone grain size reduction, according to the recommendations in AMIRA (2002). For this study, samples will undergo NAG testing according to the standard preparation methods outlined in AMIRA (2002), in order to confirm the terminal acid generation potential of the ROM samples. Lastly, all samples will be submitted for mineralogical analysis by X-ray diffraction (including Reitveld refinement).

The results of Phase I analysis will inform sample selection for Phase II and Phase III testing. The results of Phase I testing will be described in the co-placement study report.

5.1.3 Phase II – Detailed Mineralogical Analysis The objective of the detailed mineralogical examination is to identify the mineralogical source and availability (i.e. degree of liberation) of minerals capable of contributing to the NP and AP of each sample. A subset of samples will be selected for detailed mineralogical analysis based on the results of solid phase characterization (Figure 5-1). The samples will be selected to represent the compositional range of the materials that underwent Phase I testing, particularly with respect to acid generation potential.

Mineralogical analysis will be conducted using Quantitative Evaluation of Materials by Scanning Electron Microscopy (QEMSCAN) and Electron Microprobe Analysis (EPMA), which will include the following:

assay reconciliation using QEMSCAN and whole rock analysis to determine the whole rock composition of the material;

modal mineralogy to determine the general mineralogical composition of the sample;

deportment (i.e., distribution) of all minerals capable of contributing to AP and NP in each sample (to be defined with the laboratory during program set-up);

AP and NP source-mineral liberation and association (by mass and normalized distribution);

cumulative grain size distribution; and,

grain size distribution of the mineralogical sources of AP and NP, overall and within each liberation class.

To reliably determine the distribution and deportment of sulphide and neutralizing minerals in ROM rock, samples will not undergo any form of grain size reduction prior to mineralogical analysis. The results of Phase II testing will be used to determine the availability of AP and NP in ROM rock, and the associated influence on effective NP. This information will be considered in the interpretation of Phase III test results. The results of Phase II testing will be described in the co-placement study report.



5-6

5.1.4 Phase III – Laboratory Leach Testing The objective of the laboratory leach testing program is to determine how waste rock weathering rates are affected by temperature and grain size. Laboratory leach test results will be interpreted in the context of Phase I (material characterization) and Phase II (detailed mineralogical analysis) test results to determine the effective NP in blasted, ROM waste rock under variable temperature conditions. A secondary objective of this test is to evaluate the effect of mixed waste rock on long-term leachate chemistry. The mixing ratio will take into account the results of grain size analysis (Phase I), and historical results of grain size testing at the Ekati mine.

Laboratory-scale leach tests will be conducted using HCTs. The HCT method is a standard, and broadly accepted method for accelerating weathering rates of mined materials (Maest and Nordstrom 2017). The use of the HCT method is consistent with the kinetic testing method for the Ekati mine, and will allow for direct comparison of the results of the co-placement study to the extensive existing geochemical dataset and data available in the literature from nearby mines (e.g., Langman et al. 2014 and Langman et al. 2015). Use of a standard test method in controlled, laboratory conditions will allow for quantitative comparison of mineral reaction rates, which will thereby allow for evaluation of factors that influence effective NP.

As stated in the GARD Guide (INAP 2010), “it is important that the objectives of kinetic testing are clearly defined so that an appropriate test method is selected and adjusted to simulate site-specific conditions and the intended use of the data produced”. Therefore, in addition to HCTs conducted using the standard method, modified HCTs will be designed for the testing of ROM waste rock. In combination, the HCT results from this study can be used to confirm the efficacy of using standard HCT results to predict field conditions, and support the decision making process with respect to the proposed NP/AP ratio for the co-placement zone.

A humidity cell is a weathering chamber designed to provide simple control over air, temperature, and moisture, while allowing for the removal of weathering products (principally sulphide oxidation products) in solution (ASTM 2013). Standard HCTs typically consist of a 1 kg sample (dry equivalent) that has undergone grain size reduction to less than 6.3 mm. Humidity cells are typically conducted in room-temperature conditions (approximately 20 degrees Celsius [°C]). The HCTs undergo a weekly leaching cycle, which consists of a three-day period where dry air is circulated in the cell, followed by a three-day period where humid air is circulated in the cell and a final leach day when the cell is flooded with 1 litre of distilled water. The water is then drained from the cell, filtered, and submitted for analysis.

Grain size and temperature are two of several factors that can influence mineral reaction rates and associated leachate composition in laboratory tests (Maest and Nordstrom 2017). Grain size and temperature are also two key influences on effective NP. Grain size reduction and room-temperature conditions that are part of the standard HCT method can increase mineral reaction rates relative to those in a field setting. Grain size reduction can change the degree of exposure and liberation of acid generating and acid neutralizing minerals compared to that in ROM rock. Lowering the average temperature of the HCT set-up serves to suppress sulphide mineral oxidation rates, as proven by work completed by Langman et al. (2015) on similar samples of low-sulphide rock collected from the nearby Diavik Mine. Dissolution of neutralizing minerals may also be slowed down by lower temperatures.



5-7

The laboratory leach testing program has been designed to consider multiple test conditions for each sample. The total number of samples to undergo testing will be determined based on the results of solid phase analysis (Phase I), to adequately represent the range of characteristics of the sampled materials relative to the existing Ekati mine geochemical dataset. As presented in Figure 5-1, samples identified for laboratory leach tests will be homogenized and split into sub-samples. The first fraction will undergo grain size reduction (<6.3 mm), according to the standard HCT method. This material will be used to construct two standard HCTs, one of which will be conducted at room temperature (“control sample”) and the other will be conducted in a cold environment (approximately 5°C). The control HCT is necessary for each sample for direct comparison to the existing HCT dataset, and development of lithology-specific effective NP scaling factors to account for grain size and temperature variations. The remaining material will be used to construct two HCTs of unmodified, ROM waste rock. A larger-than-standard HCT configuration will be required to test this coarser grain size material; the configuration of the HCT column will be designed on the receipt of the grain size distribution results. One sample will be leached according to the standard HCT cycle in room temperature conditions, and the other will be leached using the standard HCT cycle in a cold environment.

Kinetic testing samples will be selected based on the results of solid phase analysis. It is anticipated that the HCT sample set will consist of a combination of representative samples of granite and metasediment, selected based on a range of geochemical characteristics, including total sulphur content and NP. The results of kinetic testing of these samples will allow for evaluation of influence of grain size on effective NP by lithology. Furthermore, testing of individual rock samples will allow for direct comparison to the existing Ekati mine kinetic testing dataset. In addition, samples of granite and metasediment will also be blended prior to HCT testing to evaluate the influence of material blending on effective NP. However, layering of samples in the laboratory leach tests will likely not return meaningful results with respect to effective NP, as the small scale of laboratory leach tests will not replicate large-scale flow processes or reaction rates that will occur in the field setting. Therefore, layering and the effect of “hot spot development” (i.e. zones of unblended metasediment) will be investigated as part of the future Misery WRSA Program, discussed in Section 5.3.

All HCT results will be evaluated with respect to short and long-term chemical trends related to sulphide oxidation and concomitant buffering reactions. Key reactions that contribute to the composition of HCT leachate will be determined based on the results of mineralogical analysis (Phase II). Mineral reaction rates will be assessed with respect to temperature and grain size effects, composition, and the effect of blending. The results of Phase III testing will be described in the co-placement study report.

5.1.5 Phase IV - Future Geochemical Testing The Phase I and II geochemical tests will be repeated on samples of waste rock from the Jay Pit when available during the first year of mining at the Jay Mine. This information will be used to supplement the existing Ekati mine geochemical dataset. The results of testing will be reported to the WLWB in the subsequent annual report following the first year mining at Jay. In addition, Jay waste rock may be used to construct field-scale leach tests (field cells), to confirm the leaching characteristics of Jay waste rock in site-specific climate conditions. The value of field-scale tests concurrent with construction of the WRSA will be evaluated based on the results of the Phase I and II testing of Jay waste rock. This evaluation and, if appropriate, the design of a field-scale test program will be included in the co-placement study report (Section 6).



5-8

5.2 Waste Rock Placement Optimization and Monitoring During Mining

5.2.1 Waste Rock Placement Optimization The initial Jay WRSA design was optimized such that the required NP/AP ratio would be achieved within the co-placement zone throughout the WRSA operation (Figure 4.2) while also enabling progressive final capping of the WRSA.. The preliminary construction sequence for the Jay WRSA (described in Golder [2016]) involves advancing the initial waste rock within the co-placement area to the full height of the pile and then constructing the remainder of the co-placed materials by dumping from the full height of the pile.

This proposed construction strategy methodology differs from the currently employed strategy at Ekati of building the piles from the ground up in horizontal lifts. For example, at the Misery WRSA the pile was constructed in horizontal lifts alternating between 5 m layers of granite / diabase and 10 m layers of metasediment. For illustrative purposes Figure 5-2 compares the conceptual mixing geometry of co-placed materials that could result by end-dumping from the full height of the pile (“end-dumping approach”) versus building the pile up in horizontal lifts.

Figure 5-2 Comparison of Co-Placement Methods

a) Co-placement from full WRSA height b) Co-placement in horizontal lifts


The proposed end-dumping approach is appropriate for the Jay WRSA because it enhances the environmental benefits of the co-placement approach in an operationally expedient manner. As part of co-placement study, DDEC will further investigate further potential construction optimizations for the co-placement zone. The optimization process will be aimed to maximize the NP/AP ratios within the co-placement zone to mitigate acid rock drainage potential, while enabling efficient progressive capping of the WRSA during construction. This optimization process will incorporate any results and conclusions from Phase I, II and III geochemical tests (specifically the results of mixed waste rock tests). The results of the optimization evaluation will be included in the co-placement study report.



5-9

5.2.2 Neutralization Potential to Acid Generating Potential (NP/AP) Monitoring

During construction, DDEC will utilize its built-in Wenco mining fleet management system to continuously record the tonnages and locations of materials placed in the Jay WRSA. Material tracking will be complemented by ongoing geochemical sampling of blasted waste rock in the Jay Pit. Waste rock mined in the Jay open pit development will be sampled at a rate of three samples per rock type, per bench, every year with geological mapping of the benches sampled to confirm that geochemical characteristics of materials being placed in the Jay WRSA fall within the compositional range of the Ekati mine geochemical dataset.

The material tonnages and geochemical data will be used to calculate NP/AP ratios through the construction of the Jay WRSA. Effective reporting of the NP/AP ratios during Jay WRSA construction will be an important component in ensuring that the geochemical design criteria are being achieved. In addition, efficient reporting mechanisms will enable the timely implementation of any adaptive strategies if required. An overall operational monitoring reporting plan will be developed as part of the co-placement study, which will ultimately be included in the Surveillance Network Program (SNP) and annual Ekati Water Licence Reporting frameworks. The operational monitoring plan will be described in the co-placement study report.

5.3 Misery Waste Rock Storage Area Monitoring Program A field scale geochemical and geothermal monitoring program will be undertaken at the Misery WRSA as a component of the Interim Closure and Reclamation Plan. This study is relevant to the co-placement study design; results of the field scale evaluation can be used to evaluate the site specific reactivity of co-placed granite and metasediment, in response to the following components of Schedule 6, Condition 3 of the water license:


b) whether the effective neutralizing potential/acid potential (NP/AP) characteristics of the fine rock fractions for metasediments, granite, and diabase are different in samples of rock blasted during mining, than in samples of rock prepared for humidity cell testing, and if so, a means of accounting for the differences when managing the proposed co-placement of rock in the WRSA;

e) any other testing or analysis that will inform the most appropriate NP/AP ratio and the co-placement method, limits, and controls for blending and/or layering.”

The waste rock types (granite and metasediment) encountered at Misery are compositionally similar to those that will be mined from the Jay Pit. Although the Misery WRSA was constructed by placing alternating layers of metasediment (10 m) and granite (5 m) on a 5-m thick basal layer of granite, the Misery WRSA can be considered a site-specific analogue to the Jay WRSA. Material placement began in the Misery WRSA in 2001; therefore, the existing WRSA provides a unique, site-specific source of relevant information.



5-10

Operational activities at the Misery WRSA will cease upon completion of the closure cover. If the Misery Underground Project is approved and implemented (currently under review by the WLWB), closure of the Misery WRSA would be deferred by several years; however the operationally active area of the WRSA for Misery Underground Project would be small such that some or all of the investigation described below might be safely initiated. A geochemical and geothermal investigation has been designed to gather information from the completed Misery WRSA that will enhance predictions of the performance of the Jay WRSA. The design of the investigation may be refined based on the results of the Phase I, II and III geochemical tests (Section 5.1 above), in which case those refinements will be described in co-placement study report.

The design of the Misery WRSA investigation builds on the experience gained from a similar investigation conducted at the completed Fox WRSA in 2015, and will include the following:

Geothermal monitoring to evaluate the status and progression of permafrost aggradation in the pile, and to identify whether there are zones of currently unfrozen material that can be attributed to sulphide oxidation, if any. This will provide for installed instrumentation (e.g., ground temperature cables) that enables on-going collection of thermal data for the purposes of the Interim Closure and Reclamation Plan.

Coring, to be completed using a method that will allow for retrieval of a continuous column of material from the pile. The drill core will be visually logged with respect to visible signs of alteration (e.g., color variation, staining), grain size variation, moisture content and presence of ice lenses. The Ekati mine has experience with this nature of investigation through a similar coring program conducted at the Fox WRSA.

Samples will be collected for the purpose of geochemical testing, to represent various lithological and configurational conditions within the pile. The Ekati mine has experience with this nature of sampling and analysis through a similar program conducted at the Fox WRSA.

The Misery WRSA investigation will be complementary to the geochemical testing program (Section 5.1). The results of the Misery WRSA investigation will be evaluated with respect to the sensitivity of the effective NP/AP ratio to imperfect mixing for the proposed co-placement management plan. The results of the WRSA investigation will be reported to the WLWB within 9 months of completion of the field work, along with discussion of implications for design or operation of the Jay WRSA (i.e., WROMP).


Section 6, Reporting October 4, 2017

7-1

6 REPORTING A co-placement study report will be prepared following the completion of the first 20 weeks of kinetic testing (Phase III). The co-placement study report will include the results of Phase I, II and III geochemical testing. The results will be interpreted in the context of the study objectives, and the existing Ekati mine geochemical dataset. Specifically, the results of the geochemical study will be interpreted to determine the effect of blasting on effective NP, and the associated influence on NP/AP ratio. In addition, the test results will be used to determine the sensitivity of NP/AP ratio to imperfect mixing in the co-placement zone.

The geochemical test results will be used to inform the waste rock placement optimization plan. In addition, the operational NP/AP monitoring plan will be outlined in the study report.

Recommendations for ongoing testing, including field-scale testing, will be provided if necessary.

7 SCHEDULE Table 7-1 presents the estimated proposed implementation schedule for the co-placement study components. It is estimated that a final study report can be delivered to the WLWB approximately 1 year after WLWB approval of the study design. Timely stakeholder review and review of the study design components is necessary as DDEC is prepared to initiate the study imminently.

In fact, due to restrictions of sample availability, samples for the geochemical are required to be collected (in November of 2017) for storage at a laboratory facility until testing can begin. Implementation of the geochemical and geothermal monitoring program (as part of reclamation research) at the Misery WRSA is also planned to begin in the winter of 2018.

Table 7-1 Proposed schedule for co-placement study design

Study Component From To Approval of co-placement study design by WLWB Geochemical Phase I - Material characterization Week 1 Week 2 Selection of samples for Phase II and Phase III testing Week 1 Week 2 Phase II - Detailed mineralogical analysis Week 3 Week 9 Phase III - Laboratory leach testing Week 3 Week 43 Waste Rock Placement Optimization Week 1 Week 43 Co-Placement Study Final Report to WLWB Week 52


Section 8, Closure October 4, 2017

8-1

8 CLOSURE The co-placement study design presented in this document has been prepared in response to the Water License amendment decision letter, and the requirements of the Water License amendment (Condition 6, Schedule 3) for the Project. On approval of the study design by the WLWB, the study will initiate on a timeline that is amenable to the schedule for the Jay amendment to the WROMP for the Ekati mine.


Section 9, References October 4, 2017

9-1

9 REFERENCES ASTM (American Society for Testing and Materials). 2001. ASTM Designation: D 5744 - 96 – Standard

Test Method for Accelerated Weathering of Solid Materials Using a Modified Humidity Cell, ASTM, West Conshohocken, PA, USA, 3 pp. DOI: 10.1520/D5744.

AMIRA International Ltd, 2002. ARD Test Handbook – Prediction and Kinetic Control of Acid Mine Drainage. Environmental Geochemistry International Pty. Ltd. and Ian Wark Institute, University of South Australia.

DDEC (Dominion Diamond Ekati Corporation) 2014. Jay Project Developers Assessment Report. Submitted to the Mackenzie Valley Environmental Impact Review Board. November 2014.

DDEC. 2016b. Waste Rock and Ore Storage Management Plan Version 6.1. September 2016.

Golder. 2016. Jay Waste Rock Storage Area Design Report. Submitted to Dominion Diamond Ekati Corporation. May 2016.

INAP (International Network for Acid Prevention). 2009. Global Acid Rock Drainage Guide (GARD Guide). Available at: http://www.gardguide.com/. Accessed on: September 25, 2017.

Langman, J., Moore, M., Ptacek, C., Smith, L., Sego, D., and Blowes., D. 2014. Diavik waste rock project: Evolution of mineral weathering, element release and acid generation and neutralization during a five-year humidity cell experiment. Minerals. 4. 257-278.

Langman, J., Blowes, D., Sinclair, S., Krentz, A., Amos, R., Smith, L., Pham, H., Sego, D., and Smith, L. 2015. Early evolution of weathering and sulfide depletion of a low-sulfur, granitic, waste rock in an Arctic climate: A laboratory and field site comparison. Journal of Geochemical Exploration. 156. 61-71.

Maest, A. and Nordstrom, D.K. 2017. A geochemical examination of humidity cell tests. Applied Geochemistry. 81: 109-131.

MEND (Mine Environment Neutral Drainage). 2009. Prediction Manual for Drainage Chemistry from Sulphidic Geologic Materials. MEND Report 1.20.1. December 2009.


October 4, 2017

Appendix A Conformance Table for Co-Placement

Study Design

Waste Rock Storage Area Co-Placement Study Design Jay Project

Appendix A, Conformance Table for Co-Placement Study Design

October 4, 2017

A-1

Table A-1 Conformance Table for Co-Placement Study Design

Schedule Condition Part Study Design Component

6 3 The study outlined in the Jay Waste Rock Co-placement Study Design, referred to in Part H, Condition 4, shall investigate at minimum the following:

6 3

a) the sensitivity of effective neutralizingpotential/acid potential (NP/AP) to imperfect mixing for the propose co-placement management plan;

Section 5.1.4 (Phase III: Laboratory Leach Testing) Section 5.3 (Misery WRSA Monitoring Program)

6 3

b) whether the effective neutralizing potential/acidpotential (NP/AP) characteristics of the fine rock fractions for metasediments, granite, and diabase are different in samples of rock blasted during mining, than in samples of rock prepared for humidity cell testing, and if so, a means of accounting for the differences when managing the proposed co-placement of rock in the WRSA;.

Section 5.1.3 (Phase II: Detailed Mineralogical Analysis)

6 3

c) how to optimize co-placement methods ofblending and layering for the proposed co-placement of the potentially acid generating (PAG) and non-PAG rock to prevent acid rock drainage and metal leaching; and

Section 5.2 (Waste Rock Placement and Monitoring)

6 3

d) any other testing or analysis that will inform themost appropriate NP/AP ratio and the co-placement method, limits, and controls for blending and/or layering.”

Section 5



Ekati Mine Interim Closure and Reclamation Plan Version 3.0 Appendix F: Flooding Optimization Study August 2018

Golder Associates Ltd. Suite 200 - 2920 Virtual Way Vancouver, BC, V5M 0C4 Canada

T: +1 604 296 4200 +1 604 298 5253

Golder and the G logo are trademarks of Golder Associates Corporation golder.com

1.0 INTRODUCTION Dominion Diamond Ekati ULC (Dominion) has retained Golder Associates Ltd. (Golder) to provide engineering services for the Ekati Diamond Mine (Ekati). As part of life of mine planning for Ekati, an Interim Closure and Reclamation Plan (ICRP) was developed in 2011 and is in the process of being updated. Closure planning for the mine includes pit backflooding with water from source lakes near the mine.

The pit backflooding plan was initially developed in 2007 (EBA 2007) and was updated in 2013 (EBA 2013). New developments since 2013 at Ekati require an update to the backflooding plan and schedule. Golder has developed a new and optimized backflooding plan to be included as part of an update to the ICRP.

This memorandum will present the update and optimization of the pit backflooding plan and schedule.

2.0 OPEN PITS For closure of the pits at Ekati, water is pumped from source lakes to the pits. All pits will be backflooded, or provided with a water cap, as part of either progressive reclamation or mine closure.

The open pits at Ekati, along with pit volume, yearly water inflow rates, PK or water storage volumes, and required backflooding volumes are shown in Table 1.

Prior to flooding the Beartooth open pit and the Panda, Koala, and Koala North underground and open pits will be used in operations for containment of process kimberlite. For closure, a 30 m fresh water cap will be placed on top of the deposited PK.

The Misery and Lynx open pits will be used in operations for the containment and management of mine water high in Total Dissolved Solids (TDS) and pumped water elevated in Total Suspended Solids (TSS) as part of Misery Underground (MUG) and Jay Projects. For closure a 60 m fresh water cap will be placed (via active flooding) on top of high TDS mine water at Misery and 30 m of fresh water will be placed (via passive flooding) on top of settled TSS water at Lynx Pit.

TECHNICAL MEMORANDUM DATE 8 August 2018 Reference No. 1776530-E18025-TM-Rev2-2000A

TO Lukas Novy Dominion Diamond Ekati ULC

CC Kurtis Trefry

FROM David Heikkila and Janis Drozdiak EMAIL [email protected]

DOMINION DIAMOND EKATI ULC – EKATI MINE PIT BACKFLOODING OPTIMIZATION STUDY

Pit Backflooding Optimization Study Reference No. 1776530-E18025-TM-Rev2-2000A

Dominion Diamond Ekati ULC 8 August 2018

2

Table 1: Ekati Open Pits

Open Pit Pit Volume(a) (Mm3)

PK Storage or Water Storage Volume

(Mm3)

Yearly Water Inflows (m3/y)

Required Backflooding Volume (Mm3)

Sable 33.8 - 84,500 33.8

Pigeon 12.8 - 123,500 12.8

Beartooth 13.4 9.3

(PK Storage) 49,500 4.1

Panda 40.9

87.5(b) 64.6

(PK Storage) 291,000 22.9 Koala 44.5

Koala North 2.1

Fox 70.0 - 443,500 70.0

Lynx 6.7 - 64,500 6.7

Misery 40.0 23.3

(Water Storage) 92,000 16.7

Jay 94.7 - -(c) 94.7

a) Pit volume is considered to be the volume requiring back flooding (by either water or PK), not the raw volume of the pit.

b) Panda, Koala, and Koala North pits form two separate but connected pit lakes and are considered a single unit volume for PK

deposition and backflooding.

(c) Jay Pit water inflows are calculated separately and included in backflooding as hourly average flows.

3.0 SOURCE LAKES Water for pit backflooding will be pumped from source lakes. The maximum yearly draw from each source lake was determined in previous studies and was set to provide minimal impact to lake outflows. Seasonal meltwater within the catchment area of each source lake flows into the lake. The yearly water draw from each lake is set to be less than the total meltwater inflow to each source lake, thereby decreasing, but not fully eliminating, lake outflows and maintaining lake stability.

The draw from the lakes can be seasonal (summer months) or year-round. Previous studies have determined that Ursula Lake, Upper Exeter Lake, and the Long Lake Containment Facility (LLCF) should have seasonal water draw, and that Lac de Gras and Lac du Sauvage can have water draw year-round due to the significantly larger catchment area associated with these lakes. Lac du Sauvage and Lac de Gras are connected water bodies whose pumping volumes are the same, but water cannot be taken concurrently due to connection of the water bodies.

Source lakes, associated open pits, and water draw amounts are shown in Table 2.



3

Table 2: Backflooding Source Lakes

Source Lake Associated Open Pit(s) Flooding Strategy

Yearly Volume

Flow Rate

Summer Winter

Ursula Lake Sable Seasonal 2.5 Mm3/y 700 m3/h -

Upper Exeter Lake

Pigeon, Beartooth, Panda, Koala, Koala North

Seasonal 5.0 Mm3/y 1400 m3/h -

LLCF Fox Seasonal 3.5 Mm3/y 975 m3/h -

Lac de Sauvage Misery, Jay Year-Round 31.1 Mm3/y 6,500 m3/h 1,500 m3/h

Lac de Gras Lynx Year-Round 31.1 Mm3/y 6,500 m3/h 1,500 m3/h

4.0 OBJECTIVES, STRATEGY, AND OPTIONS The pit flooding plan and schedule has been regularly updated and optimized as part of updates to the mine plan. This study update incorporates the Jay Project with the following optimization objectives:

minimize the backflooding duration per pit, as well as minimizing the duration of backflooding after operations cease

utilize existing infrastructure and equipment to the extent possible

minimize the quantity of piping, pumps, and new road construction required for backflooding

The strategy for optimization of the backflooding plan and schedule is balance between backflooding time and infrastructure cost savings.

The main driver for overall completion of backflooding and mine closure is the mining of Jay Pit. Backflooding of Jay Pit will be done year-round using water drawn from Lac du Sauvage. The P/K/KN pit complex and Beartooth pit will be used as a PK storage facility during operation of the Jay Pit; therefore, backflooding of the P/K/KN pits will also begin once Jay operations cease. Deposition of PK in Beartooth pit will cease and backflooding will be completed before Jay operations end. For concurrent flooding of Jay Pit and the P/K/KN pit complex, the P/K/KN pit complex will be flooded seasonally with water from Upper Exeter Lake. This strategy allows backflooding of these pits to be complete by 4.5 – 5 years post-operations. If the P/K/KN pit complex was backflooded using water from Lac de Gras, Jay Pit and the P/K/KN pit complex would have to be flooded consecutively, instead of concurrently, thereby extending the backflooding timeline.



4

Two main options for backflooding of the pits were considered: seasonal (summer months) or year-round. Year-round backflooding would be available from Lac de Gras and Lac du Sauvage at significantly higher yearly water volumes than seasonal flooding. Year-round flooding would also require a higher cost pumping and piping system with insulation and heat tracing, as well as significantly longer pipelines leading to increased infrastructure cost. Seasonal backflooding would have smaller yearly water volumes and longer timelines for pit filling, but no insulation or heat tracing of the pipelines would be required. Seasonal backflooding also requires less piping which leads to less infrastructure cost due to the proximity of source lakes to the pits.

Seasonal backflooding was chosen as the preferred option for the majority of open pits because the main driver of the overall completion of backflooding is the Jay Project. Using seasonal backflooding, all pits other than Jay Pit, Misery Pit, and the P/K/KN pit complex would have backflooding complete prior to Jay operations completion. This strategy saves significant infrastructure quantities and costs as opposed to year-round backflooding.

For Jay Pit and Misery Pit, the water pumping barges and pipelines projected for use as part of Jay Project will be re-utilized for backflooding, including insulated and heat traced pipelines for year-round water pumping.

All purchased water pumps for pit backflooding will be assumed to be Godwin HL 250 M (or similar) dry-prime pumps with piping optimized for each pit or pit system. The pump selection is carried through from previous studies.

Siphon systems were also considered for use. For all but Jay Pit, the siphon systems were discarded because the distance between the pit and the source water was too great for the system to function. A siphon system could work for Jay Pit because of the proximity of the source water; however, at this time Golder does not recommend a siphon system for the following reasons:

new piping, valves, and charge pumps would be required for siphoning whereas the Jay Project initial dewatering systems could be re-used for a pumped system

difficult flow control for a system with high flow rate variability between summer and winter months

siphon systems can be high maintenance when a siphon break occurs, and system re-start is required

5.0 PIT BACKFLOODING PLAN AND SCHEDULE The schedule for pit back-flooding is provided in Figure 1 and summarized in Table 3. A key schedule optimization was to ensure all pit flooding activities were completed at the end of the pit flooding for the Panda/Koala/Koala North open pits. This requires active progressive reclamation flooding during Jay operations for Fox, Sable, Beartooth, and Pigeon Pits.

The pit backflooding plan will comprise the use of new and existing pumps and pipelines, the summary of which follows:

ten (10) open pits

22 km of new HDPE piping

four (4) Godwin HL 250 M pumps (or similar)



5

2.6 km of new roads

re-use of Jay Project inflows, runoff, and return water barges

re-use of Jay Project insulated, and heat traced HDPE water piping

backflooding complete by the end of 2039 (5 years after operations cease)

As part of water licence and security estimate requirements for the Ekati project, Lynx Pit backflooding is also considered, with additional requirements as follows:

2 km of new HDPE piping

two (2) Godwin HL 250 M pumps (or similar)

The backflooding plan can be divided into five (5) systems:

Fox pipeline

Beartooth, Pigeon, Panda, Koala, Koala North pipeline

Sable pipeline

Misery and Jay system

Lynx pipeline

5.1 Fox Pipeline The Fox pipeline system will begin at the LLCF – Cell D and will transport water to Fox Pit, approximately 5 km away. Existing roads will be used for the pipeline, which will be 18-inch HDPE DR13.5 pipe. One (1) Godwin pump will be used for pumping at a flow rate of 975 m3/h. The system will function using seasonal pumping beginning in 2021 and ending in 2039 for a total time of 18 years.

5.2 Beartooth, Pigeon, Panda, Koala, Koala North Pipeline The pipeline will begin at Upper Exeter Lake (UEL) and will be routed to pump water to Pigeon, Beartooth, Panda, Koala, and Koala North pits. The entire pipeline from UEL to the furthest pit, Koala, will be approximately 10 km but will be built in sections according to the order of pit flooding.

The first pit to be actively backflooded will be Pigeon Pit beginning in mid-2023. The pipeline initiating from UEL to Pigeon Pit will have a length of approximately 3.7 km. and a new access road to UEL of approximately 1.6 km will be constructed. The pipeline will be 24-inch HDPE DR13.5 pipe. Two (2) Godwin pumps, configured in parallel, will be used for pumping at a total flow rate of 1,400 m3/h, or 700 m3/h per pump. The system will function using seasonal pumping for two and a half (2.5) years, ending in 2025.



6

The pipeline will remain in place until mid-2034, when PK deposition in Beartooth Pit will cease. Before PK deposition ceases, the pipeline will be extended, and the system will begin pumping water to Beartooth Pit. The pumping will function seasonally for one (1) year, ending in mid-2035, before P/K/KN backflooding begins.

In mid-2035, mining will be completed for Jay Pit and PK deposition will cease to the P/K/KN pit complex. An approximately 2 km extension to the pipeline will be constructed from Beartooth Pit to the P/K/KN pit complex before PK deposition is finished. The P/K/KN pit complex will then be backflooded for four and a half (4.5) years, ending at the end of 2039.

5.3 Sable Pipeline The Sable pipeline system will begin at Ursula Lake and will transport water to Sable Pit, a distance of approximately 4 km. New access road construction of approximately 1 km will be required. The pipeline will be 16-inch HDPE DR17 pipe. One (1) Godwin pump will be used for pumping at a flow rate of 700 m3/h. The system will function through seasonal pumping beginning in 2027 and ending in 2039 for a total time of 13 years.

5.4 Misery and Jay System Misery Pit and Jay Pit backflooding will be completed using existing infrastructure from the Jay Project initial dewatering, final dewatering, and operations.

Existing infrastructure includes the following:

initial dewatering pumps and piping

inflows, runoff, and return water pumps, barges, and piping

24-inch HDPE DR9 / DR21 (insulated and heat traced)



Misery Pit will initially require the removal of 10.67 Mm3 of operational water stored as part of the Jay Project. This water will be pumped to the bottom of Jay Pit to allow for the backflooding of the Misery Pit 60 m fresh water cap. The runoff barge located in the Jay Pit runoff sump will be relocated to Misery Pit. Approximately 200 m of 24-inch HDPE DR9 pipe will be required to replace the initial 200 m of piping of the runoff pipeline, to provide adequate pressure containment.

The runoff pumping system and pipeline, and the return pumping system and pipeline, will then function to pump water from Misery Pit to Jay Pit at a flow rate of 3,350 m3/h for a duration of 4.5 months. No new access roads are projected to be required.



7

The backflooding of Misery Pit to form the 60 m water cap, a volume of 16.67 Mm3, will be completed using the Jay Project inflows barge pumping system and pipeline. The barge will be relocated from the Jay Pit inflows sump to Lac du Sauvage, and will pump at a flow rate of 1,500 m3/h for 1.5 years. The pumping will occur year-round, ending in 2036.

The backflooding of Jay Pit from Lac du Sauvage, a volume of 94.7 Mm3, will be completed using the Jay Project initial dewatering pumps and piping. This system of multiple high-flow low-head pumps, configured in parallel, will pump water over the Jay dykes and into Jay Pit at flow rates varying from 1,500 m3/h to 5,000 m3/h to 6,500 m3/h depending on the season and the status of Misery Pit backflooding. The pumping will occur year-round, will begin in mid-2035, and will end in mid-2038.

5.5 Lynx Pipeline The Lynx pipeline system will begin at Lac de Gras and will transport water to Lynx Pit, a distance of approximately 2 km along the existing road alignment. The pipeline will be 16-inch HDPE DR17 pipe. Two (2) Godwin pumps will be used for pumping at a flow rate of 1,500 m3/h, or 750 m3/h per pump. The system will function through seasonal pumping for a total time of one (1) year. This system will only be required if Jay Pit is not developed. If Jay Pit is developed, Lynx pit will be passively backfilled during operations.

5.6 Summary A summary of the active back flooding schedule is shown in Table 3. Table 3: Active Backflooding Schedule Summary

Open Pit Start End Duration (years)

Sable 2027 2039 13

Pigeon 2023 2025 2.5

Beartooth 2034 2035 1

Panda/Koala/Koala North 2035 2039 4.5

Fox 2021 2039 18

Lynx(a)

Lynx(b) N/A 2023

N/A 2024

N/A 1

Misery 2035 2036 1.5

Jay 2035 2038 3

(a) Lynx Pit will be passively backflooded for 5.5 years during operations.

(b) Lynx Pit will be actively backflooded if Jay Project does not proceed.



8

A summary of infrastructure required is shown in Table 4. Pumps are designated as P1 through P6. Barges are reused from Jay Pit operations.

Table 4: Backflooding Systems Summary

System

Pumps Pipelines (New Purchase) Access

Roads (New) No. of Pumps

(New Purchase)

Pump / Barge

Total No. of Pumps Quantity Type

Fox 1 P4 1 5,000 m 18-inch DR13.5 -

Pigeon, Beartooth, Panda, Koala, Koala North

2 P1/P2

2

10,000 m +2,000 m

24-inch DR13.5 1.6 km

Sable 1 P3 1 4,000 m 16-inch DR17 1.0 km

Misery, Jay -

Initial, Inflows, Runoff, Return

Misery – 3 Jay – 6 (initial),

3 (final)

200 m 24-inch DR9 -

Lynx(a) 2 P5, P6 2 2,000 m 16-inch DR17 -

Total: 4

(6 with Lynx)

16 (18 with Lynx)

21,200 m (23,200 m with Lynx)

2.6 km

(a) Lynx system information kept separate because Lynx Pit backflooding would only be required if Jay Project is not advanced.

A summary of the fuel consumption of the pumps associated with backflooding each pit is presented in Table 5.

Table 5: Summary of Backflooding Fuel Consumption

Open Pit Total Fuel Consumption (litres)

Sable 4,390,000

Pigeon 1,663,000

Beartooth 533,000

Panda/Koala/Koala North 2,976,000

Fox 6,530,000

Jay 2,390,000



9

Open Pit Total Fuel Consumption (litres)

Misery(a) N/A

Lynx(b) 813,000

(a) Misery backflooding will be completed using equipment that is connected to the electrical grid. It requires a total of 7,660,000 kWh.

(b) Lynx Pit backflooding would only be required if Jay Project is not advanced.

5.7 Backflooding Schedule The schedule for backflooding is shown in Figure 1.

Figure 1: Backflooding Schedule



11

REFERENCES EBA Engineering Consultants Ltd. 2007. Open Pit Flooding Study Ekati Diamond Mine.

Ref. 0101-94-11580013.006, Rev2.

EBA Engineering Consultants Ltd. 2013. Pit Flooding Plan with the LLCF. Ref. E14103159-01.

ADDENDUM 1

Ekati Mine Closure – Unit Costs Pump Flooding

Golder Associates Ltd. Suite 200 - 2920 Virtual Way Vancouver, BC, V5M 0C4 Canada

T: +1 604 296 4200 +1 604 298 5253

Golder and the G logo are trademarks of Golder Associates Corporation golder.com

Preliminary estimates for unit costs related to the pump flooding activities have been developed. The estimates have been developed as unit costs for use directly in the RECLAIM cost estimating model. All dollar amounts are in 2018 Canadian dollars.

1.0 PUMPS AND PIPELINES Unit costs for pipelines (capital and installation) have been estimated. Capital costs are based on 2018 vendor quotes and installation costs have been developed based on experience with similar projects, considering northern conditions.

All pump requirements have been calculated considering the use of Godwin HL 250 M pumps (or similar). Based on 2018 supplier quotes, the estimated cost per pump is $239,000. A value of 10% of pump CAPEX ($24,000) has been assumed for average annual pump maintenance costs.

Pumps (with the exception of Misery) will be outfitted with diesel power, and fuel consumption is estimated to be 24 US gal/hour, confirmed from the manufacturer’s quote and from the pump model technical specification. At Misery, the kWh requirement can be converted to equivalent diesel (as all power at the site is ultimately provided by diesel generators. The 7,660,000 kWh requirement indicated in the principal memo is equivalent to 2.02 million US gal (or 2,553,333L based on 3 L/kWh).

Table 1: Pipeline Unit Cost Summary

Capital ($/m)

Install ($/m)

Locations

16-inch DR17 $122 $50 Sable, Lynx

18-inch DR13.5 $191 $90 Fox

24-inch DR13.5 $339.5 $165 Pigeon, Beartooth, Panda,

Koala, Koala North

24-inch DR9 $537 $165 Misery/ Jay

ADDENDUM DATE 8 August 2018 Reference No. 1776530-E18025a-TM-Rev2-2000A

TO Lukas Novy Dominion Diamond Ekati ULC

FROM Bjorn Weeks and Janis Drozdiak EMAIL [email protected]

EKATI MINE CLOSURE – UNIT COSTS PUMP FLOODING ADDENDUM

Ekati Closure – Unit Costs Pump Flooding Reference No. 1776530-E18025a-TM-Rev2-2000A


2

In the reclaim model, no unit costs will be required for “break and install pipe” as all new pipe will be considered. The 200 m pipeline for Jay and Misery can be associated with either pit, and it is suggested to associate it with Jay.

2.0 ROADS As summarized in the principal memorandum, new access roads will be required to support the installation of reclamation and closure pipelines. For the purposes of the reclaim model, a unit cost for new road at the site of $300/lin.m has been estimated.

The unit cost has been developed assuming that 2-3 km of new access roads will be required for the duration of the pit flooding activities at closure. These roads are assumed to be 8 m wide/two lane gravel roads for light vehicles/Class 8 transit. It is also assumed that the roads will follow existing grades and no blasting will be required for construction.

The costs considered in the development of the unit cost are summarized in Table 2.



3

Table 2: Unit Cost Basis - Roads

Item Description Quantity / Linear meter

Unit Unit Rate

Comment Quantity / Linear Meter

Cost / Linear Meter

1

Grubbing - rough grading where ground conditions permit - removal of organics if practical to do so.

D8 / D10 sized machine - on firm ground - not in wet or partial / full permafrost areas.

$35

2 Place 450 mm of 1 - 3" (25 - 75 mm) blast rock over top of native materials

4.05 m3 $20 Haul and place waste blast rock - processed through a site crusher

4.05 $81

3

Insulation (R-10 insulation on 8-meter wide roadway and 1.2 meters on each side into side banks

10.4 m2 $120 R-10 insulation under access road to protect permafrost

10.4 $120

4

Placement of 300 mm of open gradation blast rock from 0 - 1.5" - waste rock placed over top of insulation

3 m3 $18

Spread open gradation material over top of insulation - grade as appropriate - wet and compact as necessary

3 $54

Total $290

Culvert Installations

1 Assume one culvert every 350 linear meters of constructed road.

2

Assume 450 blue brute pipes to be installed with 600 mm of cover and insulation over top - to prevent heaving and disruption to permafrost

$1,450

Cost / meter $4.14

Total cost / linear meter of road construction.

$294.14



4

3.0 SUPPORT STAFF Support staff will be required throughout the active flooding period from 2021 to 2039, for periodic inspection and maintenance of pumps, as well as for the periodic collection of water samples and other monitoring activities.

The required level of effort has been estimated associate with each pit based on the following assumptions:

For each day of active flooding at the pit, an average of 7 staff hours will be dedicated to maintenance/inspection activities, and 3 to monitoring/sampling.

Average staff cost of $40/hr.

Supervision during Misery and Jay pumping to be year-round; all others assumed to be 8 months per year.

Estimated costs per pit are summarized in Table 3.

Table 3: Support Staff Cost

Pit Years Labour hrs Equipment

Maintenance Monitoring

Misery 1.5 5475 $153,300 $65,700

Pigeon 2.5 6083 $170,333 $73,000

Sable 13.0 31633 $885,733 $379,600

Beartooth 1.0 2433 $68,133 $29,200

Fox 18.0 43800 $1,226,400 $525,600

Panda/Koala 4.5 10950 $306,600 $131,400

Lynx 2.0 4866 $136,267 $58,400

Jay 3.0 10950 $306,600 $131,400

116,190 $3,253,367 $1,394,300

This value has been cross-checked against an alternative set of costing assumptions, considering 24 staff hours per day for every day of active pumping during the pumping period from 2021-2039, for carrying out both inspection/maintenance and monitoring activities. The total cost under this set of assumptions is effectively equal to the total cost obtained through the assumptions summarized in Table 3.


Ekati Mine Interim Closure and Reclamation Plan Version 3.0 Appendix G: Caribou Movement Patterns August 2018

HHHHHHHH

HHHHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHH HHHHHHHHHHH

HH

HHH

HHHHH

HHHHH

H HHHHHHH

HHHH

HHHH

HHH

HHHHHHHHH

HHHHHHHHHH

HHHHHHH H

HHHHH

HHH

HHH

HH

HHHH

HHH

HH HHHHH

HH

HHHH

HHHHHHHHH

HHHHH

HHHH

HH

HHHHHHHHHHHHHH

HHHHHH

HHH

HHHH HHH

H HHHHHH

HHHHHH

H

HHHHHHH

HHHH

HHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHH

HHHHH

HHHH

HHHH

H

HHH

HH

HHHHHHHH

HHHH

HHH

HHHHH

HH

HH

HHHHHHHHHHH

HHHHHHHHHHHHHHH

HHHHHHH

HH

HHHHHHHHHHHHHH

HHHHHHHHHH HH HHHH

HHHHHHHH

HHHH

HH

HHHH

HHH

HHHHHHHHHHH

HHH

H HHHHHHHHH HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHH

H HHH

HHHHHHH H

HHHHHHHHHHHHH

HHHHHHHHH

HHHHHHHH

HHHHH

HHHH HHHH

HHHHH

HHHHHHHHH

HHHH

HHHHH

HHHHHHHH

HHHHHH HHH

HHHH

HHHHHHHHHHH

HHHHHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHH

HHHHHHH

HHHH

HHH

HHHHHHHHHHH

HHHHHHHHHHHHH HHH

HH

HHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHH

!.

!.!.

!.

!.

!.

!.

!.!.

!.

!.!.!.

!.

!.

!.

!.

!.

!.

!.

!.!.!.

!.

!.!.

!.!.!.

!.

!.

JAY WRSA

MISERY WRSALYNX WRSA

LAC DUSAUVAGE

KODIAKLAKE

G05LAKE

LAKE E

LLCFCell E

LLCFCells A/B/C

SABLEPIT LAKE

FOXWRSA


FACILITY

PIGEONPIT LAKE

BEARTOOTHPIT LAKE

PANDAPIT LAKE

MAINCAMP

KOALAPIT LAKE

AIRSTRIP

LYNXPIT LAKE

MISERYPIT LAKE

MISERY ROAD

KOALANORTH

PIT LAKE

PIGEON WRSA

FOXPIT LAKE

WESTWRSA

SOUTHWRSA

LLCFCell D

PATH

: T:\0

1-pr

ojec

ts\E

kati\

Pro

ject

_MX

D\E

KA

-23-

320e

.mxd

PR

INTE

D O

N: 2

018-

08-1

3 AT

: 3:3

3:25

PM

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT



PROJECT


SITE-WIDE CARIBOU MOVEMENT

02111136-2015 #### 0 MAP G-1PROJECT NO. CONTROL REV. FIGURE

0 2 4

Kilometers1:150,000 METRES

LEGEND

HHHHHHEsker



NOTE(S)

REFERENCE(S)

2018-08-13

MS

MS

JR

LN

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED

Re c l a i me d Fe a t ur eESKER COMPLEX Misery Road, Lynx Road, Sect ion of Sable Road.

LICHEN VENEER




TALL SHRUB

PEAT BOG

BIRCH SEEP


Main Camp, Airst r ip, Inf rast ruct ure Pad, Laydown Area


REVEGETATED


Pigeon, Panda-Koala -Beart oot h , Fox, West , Sout h, Lynx, Jay and Misery WRSAs, minor sit e roads, sect ion of Sable Road, sect ion of Misery Road, Jay Dyke and t he airst r ip.

SPRUCE FOREST


ICE AND SNOW

DEEP WATER (< 2m Deep)Pigeon, Koala, Panda, Beart oot h, Fox, Koala Nort h, Sable, Misery, Lynx, Jay Pit Lakes, Two Rock Sediment at ion Pond, LLCF Cell D, LLCF Cell E and sect ions of Jay Sit e and Road.



Re c l a i me d Fe a t ur eESKER COMPLEX Sect ion of Sable Road.

LICHEN VENEER

HEATH TUNDRA ( < 30% Rock)

TUSSOCK / HUMMOCK LLCF Cells A, B and C.


TALL SHRUB

PEAT BOG

BIRCH SEEP

HEATH / BOULDER(30-80% Boulders)

Main Camp, Airst r ip.

HEATH / BEDROCK(30-80% Bedrock)

BEDROCK ASSOCIATION( > 80% Bedrock)

BOULDER ASSOCIATION( > 80% Boulders)

Pigeon WRSA, Panda-Koala -Beart oot h WRSA, minor sit e roads, sect ion of Sable Road, sect ion of Misery Road.

SPRUCE FOREST

SHALLOW WATER ( < 2m Deep)

ICE AND SNOW

DEEP WATER ( > 2m Deep) Pigeon, Koala, Panda, Beart oot h, Koala Nort h Pit lakes.


HHHHHHHHHHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHHHHHHHH

HHHHHHHHHHHHHHHHHHH

HHHHHHH

HHHHHHH

HHHHHHHH HHHHHHHHHHHH

HHHHHHHHHHHHH

!.

!.

!.

!.

!.


FACILITY

PIGEON PITLAKE

BEARTOOTH PITLAKE

PANDA PITLAKE

MAINCAMP

KOALA PITLAKE

AIRSTRIP

PIGEON WRSA

URSULALAKEBIG POND

FALCONLAKE

VULTURE LAKE

FAY BAY

BEARCLAWLAKE

PELZERPOND POLAR

LAKE

GRIZZLYLAKE

KODIAKLAKE

WHITE LAKE

EXETER LAKE

UPPER EXETERLAKE

LLCFCells A/B/C

LLCFCell D

Reclaiming Sable Road to function asesker habitat will facilitate movement ofcaribou through this movement corridor.

This area is dominated by heath tundra habitat.TK indicates a movement corridor through the area.

Objective is to maintain existing movement corridorsalong the southern shore of Upper Exeter Lake anddiscourage use of poor quality habitat in thePanda-Koala-Beartooth WRSA complex and pit lakes.

66 ha of low quality boulderassociation habitat at closure.

The revegetated LLCF will be dry, flat andstable, posing low risk to caribou movingthrough the area. Also an area of limitedforage potential unlikely to attract caribou.

Panda-Koala-Beartooth WRSA representsapproximately 341 ha of low quality boulderassociation habitat at closure. At 1km wideand 3km long, is a potential barrier to movement.

The LLCF and Panda-Koala-Beartooth WRSAcomplex are both surrounded by habitat andterrain that will not facilitate safe movement ofcaribou (i.e., water, heath/boulder heath/bedrock).

PATH

: T:\0

1-pr

ojec

ts\E

kati\

Pro

ject

_MX

D\E

KA

-23-

320a

.mxd

PR

INTE

D O

N: 2

018-

08-1

3 AT

: 3:3

1:37

PM

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT



PROJECT

EKATI DIAMOND INTERIM CLOSURE AND RECLAMATION PLANVER. 3.0TITLE PIGEON, PANDA, KOALA, BEARTOOTH, LLCF AREA SITEWIDE - PRELIMINARY ANALYSIS OF RECLAIMED EKATI MINE ANDCARIBOU MOVEMENT PATTERNS

02111136-2015 #### 0 MAP G-2

2018-08-13

MS

MS

JR

LN

PROJECT NO. CONTROL REV. FIGURE

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED

0 1,000 2,000

1:50,000 METRES

LEGEND

HHHHHH ESKER !. Caribou Crossing Ramp

NOTE(S)

REFERENCE(S)


HHHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHHHHH HHHHHH

HHHHHHHHHHHHHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHH

HHHHH

"

"

!.

!.

!.

!.LLCFCell D

LLCFCell E

FOXWRSA

MAINCAMP

AIRSTRIP

FOXPIT LAKE

LLCF Cells A/B/C

KODIAKLAKE

WHITE LAKE

LITTLELAKE

LARRYLAKE

MOOSELAKE

LESLIELAKE

AIRSTRIPLAKE

NEROLAKE

NEMA LAKE

MIKE LAKE

ONE HUMP LAKE

THREEHUMPLAKE

MARTINE LAKE

FISHTWO LAKE

RENNIE LAKE

FOX TWO LAKE

LAKE C

FISHONELAKE

FOX THREELAKE POND D

G05LAKE

LAKE E

NORA LAKE

SLIPPERLAKE

G09LAKE

LAC DE GRAS LAC DE GRAS

Collar data indicate very low movementand use of this area due to the rugged terrain.

The WRSA is surrounded by poorterrain for access and/or egress.

The Fox WRSA represents 320 haof low quality boulder associationhabitat at closure.

The Fox WRSA is surrounded by low qualityheath/bedrock and heath/boulder habitat,which is unlikely to be used by caribou.

PATH

: T:\0

1-pr

ojec

ts\E

kati\

Pro

ject

_MX

D\E

KA

-23-

320b

.mxd

PR

INTE

D O

N: 2

018-

08-1

3 AT

: 3:3

2:01

PM

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT



PROJECT


FOX AREA TARGET RECLAMATION LAND CLASSIFICATIONSOVERLAIN ON WEST KITIKMEOT SLAVE STUDY LAND


0 1,000 2,000

1:50,000 METRES

LEGEND

HHHHHH Esker !. Caribou Crossing Ramp

NOTE(S)

REFERENCE(S)

2018-08-13

MS

MS

JR

LN

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED

Re c l a i me d Fe a t ur eESKER COMPLEX

LICHEN VENEER


TUSSOCK / HUMMOCK LLCF Cells A, B and C.


TALL SHRUB

PEAT BOG

BIRCH SEEP


Main Camp, Airst r ip.




Fox WRSA, minor sit e roads, nort hern sect ion of Misery Road

SPRUCE FOREST


ICE AND SNOW

DEEP WATER ( > 2m Deep) LLCF Cell D, LLCF Cell E and Fox Pit Lake.



HHHHHHHHHHHHH

HHHHHHHHHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHHHHHHHH

HHHHHHHHHHHHHHHHHHHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHHHHHHHHHHHHH

HHHHHHHHHHHHHHHHHHHH

!.

!.

!.

JAYWRSA

The Misery-Lynx WRSA complex is surrounded byby deeper water bodies to the south and east.LYNX

PIT LAKE

MISERYPIT LAKE

MISERY WRSA

MISERY ROAD

LYNX WRSA

SUBMERGEDJAY PIT LOCATION

LAC DUSAUVAGE

LAC DE GRAS

CHRISTINELAKE

STANDPOND

POINTLAKE

SHININGPOND

CUJOLAKE

THINNERLAKE

KINGPOND

MOSSINGLAKE

MISTLAKE

PHANTOMLAKE

FISHER LAKE

Jay WRSA represents 227 ha of low qualityboulder association habitat at closure.

TK indicates a northwest-southeastmovement corridor following the esker.

Jay WRSA is surrounded by a mosaic of cover types,including wetlands, boulder and deep water, which limitsopportunities to create safe access and egress options for caribou.

TK identified the Narrows as animportant migratory corridor for caribou.

Misery WRSA represents 119 ha of lowquality boulder association habitat at closure.

Lynx WRSA represents 32 ha of low qualityboulder association habitat at closure.

Reclamation may consider treating the Lynx Pitroad to function as an esker, and ramps tothe Lynx WRSA for access and egress.

The Misery-Lynx WRSA complex is surrounded byhigher quality tundra habitat to the west and southwest.

PATH

: T:\0

1-pr

ojec

ts\E

kati\

Pro

ject

_MX

D\E

KA

-23-

320c

.mxd

PR

INTE

D O

N: 2

018-

08-1

3 AT

: 3:3

2:29

PM

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT



PROJECT

EKATI DIAMOND INTERIM CLOSURE AND RECLAMATION PLANVER. 3.0TITLEMISERY AREA - PRELIMINARY ANALYSIS OF RELCAIMED EKATI MINEAND CARIBOU MOVEMENT PATTERNS


0 1,000 2,000

1:50,000 METRES

LEGEND

HHHHHH Esker



NOTE(S)

REFERENCE(S)

2018-08-13

MS

MS

JR

LN

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED

Land Classification Data in table are listed in order fromhighest to lowest quality in terms of facilitating caribou movement.

Re c l a i me d Fe a t ur eESKER COMPLEX Misery Road, Lynx Road.

LICHEN VENEER


TUSSOCK / HUMMOCK


TALL SHRUB

PEAT BOG

BIRCH SEEP


Laydown Area.




Misery WRSA, Lynx WRSA, Jay WRSA, minor sit e roads, and a sect ion of Misery Road, Jay Dyke.

SPRUCE FOREST


ICE AND SNOW

DEEP WATER ( > 2m Deep) Misery Pit , Lynx Pit , Jay Pit , sect ions of Jay Sit e and Roads.


HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH HHHHHHHHHHHHHH

HHHHHH HHHHHHHH

HHHHHHHHHHHHHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HH

HHH

HHHHHHHHHHHHHHHHH HHHH HHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHHHHHH

HHHHHHHH

HHHHH

HHHHHHHHHHHHHHHHHHHHHH

HHHHHHHHH

HHHHHHHHHHHHHHH

HHHHHHH

HHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

HHHHHHH

HHHHHHHHHHHHHHHHHHHHHH

HHHHH

HHHHHHH

HHHHHHHHHHHHH

HHHHHHHH

!.

SABLEPIT LAKE

WESTWRSA

SOUTHWRSA

EASTWRSA

URSULALAKE

BIG POND

BAT05LAKE

ROCKY LAKE

OBERON LAKE

ROSS LAKE

MINKLAKE

HORSESHOELAKE

ULULAKE

OSPREYLAKE

EAGLE LAKE

Movement is potentially impeded to the north of theWRSA due to Horseshoe and Ulu lakes and thepresence of heath/boulder and heath/bedrock habitat,which limits opportunities for safe access/egress options.

The heath tundra habitat to the southand east of the WRSA has potentialfor safe access/egress options.

The Sable WRSAs represent 182 ha(Combined 93+72+17) of low qualityboulder association habitat at closure.

Reclamation of Sable Road to functionas an esker complex is a priority item thatis likely to benefit caribou movements.

PATH

: T:\0

1-pr

ojec

ts\E

kati\

Pro

ject

_MX

D\E

KA

-23-

320d

.mxd

PR

INTE

D O

N: 2

018-

08-1

3 AT

: 3:3

2:55

PM

IF T

HIS

ME

AS

UR

EM

EN

T D

OE

S N

OT

MAT

CH

WH

AT IS

SH

OW

N, T

HE

SH

EE

T S

IZE

HA

S B

EE

N M

OD

IFIE

D F

RO

M: A

NS

I B25

mm

0

CLIENT



PROJECT

EKATI DIAMOND INTERIM CLOSURE AND RECLAMATION PLANVER. 3.0TITLESABLE AREA - PRELIMINARY ANALYSIS OF RECLAIMED EKATI MINEAND CARIBOU MOVEMENT PATTERNS


0 1,000 2,000

1:50,000 METRES

LEGEND

HHHHHH Esker !. Caribou Crossing Ramp

NOTE(S)

REFERENCE(S)

Sable Pit lake, Two Rock Sedimentation Pond

West and South WRSA, , minor site roads, and the Sable site section of Sable Road

Sections of Sable Road

2018-08-13

MS

MS

JR

LN

YYYY-MM-DD

DESIGNED

PREPARED

REVIEWED

APPROVED

Infrastructure Pad


Re c l a i me d Fe a t ur eESKER COMPLEX Sect ion of Sable Road.

LICHEN VENEER




TALL SHRUB

PEAT BOG

BIRCH SEEP




Pigeon WRSA, Panda-Koala -Beart oot h WRSA, minor sit eroads, sect ion of Sable Road, sect ion of Misery Road and t he airst r ip.

SPRUCE FOREST


ICE AND SNOW

DEEP WATER (< 2m Deep) Pigeon, Koala, Panda, Beart oot h, Koala Nort h Pit lakes.



Ekati Mine Interim Closure and Reclamation Plan Version 3.0 Appendix H: Reclaim Estimate August 2018

Reclaim 7.0 Project: EKATI DIAMOND MINE 8/14/2018

OPEN PITSMisery $4,967,098Pigeon $5,497,714Sable $7,069,879Beartooth $4,807,090Fox $10,249,072Panda $4,527,375Koala North $2,950,512Koala $2,181,849Lynx $2,567,460Jay $2,762,534OPEN PIT TOTAL: $47,580,582

TAILINGS Cell A $9,811,565Cell B $9,304,831Cell C $12,179,068Cell D $92,298Cell E $455,112Phase 1 $599,954TAILINGS TOTAL $32,442,829

ROCK PILESFox WRSA $4,355,584Misery WRSA $10,478,336Panda/Koala Beartooth WRSA $12,355,448Pigeon WRSA $18,521,255Sable WRSA $809,962Lynx WRSA $185,690Jay WRSA $10,375,702ROCK PILE TOTAL $57,081,977

BUILDINGS AND EQUIPMENT $19,080,169

WATER MANAGEMENT $4,761,011

CHEMICALS AND SOIL CONTAMINATION $2,979,616

UNDERGROUND MINE Panda $221,686Koala $157,686Koala North $221,686Misery Underground $78,843UNDERGROUND MINE TOTAL $679,900

SUBTOTAL $164,606,083

MOBILIZATION/DEMOBILIZATION $53,593,832POST-CLOSURE MONITORING AND MAINTENANCE $14,366,800RESIDUAL RISK $656,803

PROJECT MANAGEMENT 5% $8,230,304.14ENGINEERING 5% $8,230,304.14HEALTH AND SAFETY PLANS/MONITORING & QA/QC 0.5% $823,030.41BONDING/INSURANCE 0.5% $823,030.41

CONTINGENCY (Open Pit Flooding) 10% $2,276,272CONTINGENCY (Open Pit Flooding) 15% $1,484,725CONTINGENCY (Capping) 15% $10,438,756CONTINGENCY (Buildings Decommissioning) 15% $1,983,210CONTINGENCY (Other Reclamation Activities) 20% $9,881,824.82RECLAIM ESTIMATE GRAND TOTAL $277,394,974

Total Land & Water Water Cost Land Cost$251,288,803 $251,288,803 N/A$624,458 N/A $624,458$251,913,261 $251,288,803 $624,458

Total Land and Water Water Cost Land Cost$1,824,976 $427,500 $1,397,476$3,555,748 $3,555,748 N/A$2,848,382 $2,848,382 N/A$6,786,895 $4,428,591 $2,358,304$10,465,712 $2,883,153 $7,582,559$25,481,713 $14,143,374 $11,338,339$277,394,974 $265,432,177 $11,962,797

SUMMARY OF COSTS

Misery Underground Development

Jay Early Works

Future Ekati Disturbances

Subtotal:

Ekati Site Including Sable Phase 1 & 2Current Ekati Disturbances

TOTAL

Jay Phase 1Jay Phase 2

Sable Phase 3Sable Phase 4

Subtotal:

RECLAIM Estimate ICRP Version 3.0..xlsx 1 of 35


Open Pit Name: Misery Pit # 1

ACTIVITY/MATERIAL Units Quantity Cost Code Unit Cost Cost

OBJECTIVE: CONTROL ACCESSFence and Signs each 1 FSS 10,000.00 $10,000Berm at Crest m3 38,858 SBSBS 3.98 $154,826Block Roads (20 m ramp length) m3 9,000 RCSS 7.50 $67,500Dozing m3 9,000 DSL 0.95 $8,550OBJECTIVE: CONSTRUCT LITORAL ZONESBlast Rim m3 122,711 RCSS 7.50 $920,330Dozing m3 79,762 DSL 0.95 $75,774Substrate Produce and Place m3 12,271 SCSTS 22.80 $279,756Sediment Berm Produce and Place m3 1,227 SCSBS 24.21 $29,706Vegetation ha 1 VHFL 4,000.00 $4,000OBJECTIVE: WATER MANAGEMENTOutflow Channel m3 80 #N/A 181.52 $14,522Spillway Construction m3 0 #N/A 0 $0Concrete Weir Construction m3 0 #N/A 0 $0OBJECTIVE: LOWER LYNX PITMUG Provisional Amount kwh 776949.206 #N/A 0.420022152 $326,336OBJECTIVE: LOWER & BACKFLOOD MISERY PITPump Purchase each 0 #N/A 239,000.00 $0 Ver 3.0 #4Pipe Puchase and Install m 1000 #N/A 702 $702,000 Ver 3.0 #4Pump Maintenance yr*m 1.5 #N/A 25000 $37,500 Ver 3.0 #4Pump Fuel litre 2553333 FLONAS 0.92 $2,336,300 Ver 3.0 #4

Subtotal $4,967,098



Open Pit Name: Pigeon Pit # 2


OBJECTIVE: CONTROL ACCESSFence and Signs each 1 FSS 10,000.00 $10,000Berm at Crest m3 25,070 SBSBS 3.98 $99,888Block Roads (20 m ramp length) m3 9,000 RCSS 7.50 $67,500Dozing m3 9,000 DSL 0.95 $8,550OBJECTIVE: CONSTRUCT LITORAL ZONESBlast Rim m3 79,168 RCSS 7.50 $593,761Dozing m3 51,459 DSL 0.95 $48,886Substrate Produce and Place m3 7,917 SCSTS 22.80 $180,488Sediment Berm Produce and Place m3 792 SCSBS 24.21 $19,165Vegetation ha 1 VHFL 4,000.00 $4,000OBJECTIVE: WATER MANAGEMENTOutflow Channel m3 45 #N/A 79.05 $3,557Spillway Construction m3 0 #N/A 0 $0Concrete m3 0 #N/A 0 $0OBJECTIVE: FLOOD PITPump Purchase each 2 #N/A 239,000.00 $478,000 Ver 3.0 #4Pipe Puchase and Install m 3700 #N/A 505 $1,866,650 Ver 3.0 #4Pump Maintenance yr*m 5.0 #N/A 25000 $125,000 Ver 3.0 #4Pump Fuel litre 1,663,000 FLONAS 0.92 $1,521,645 Ver 3.0 #4Access Road m 1,600 #N/A 294 $470,624 Ver 3.0 #4

Subtotal $5,497,714



Open Pit Name: Sable Pit # 3


OBJECTIVE: CONTROL ACCESSFence and Signs each 1 FSS 10,000.00 $10,000Berm at Crest m3 37,605 SBSBS 3.98 $149,832Block Roads (20 m ramp length) m3 9,000 RCSS 7.50 $67,500Dozing m3 9,000 DSL 0.95 $8,550OBJECTIVE: CONSTRUCT LITORAL ZONESBlast Rim m3 118,752 RCSS 7.50 $890,642Dozing m3 77,189 DSL 0.95 $73,329Substrate Produce and Place m3 11,875 SCSTS 22.80 $270,731Sediment Berm Produce and Place m3 1,188 SCSBS 24.21 $28,748Vegetation ha 1 VHFL 4,000.00 $4,000OBJECTIVE: WATER MANAGEMENTOutflow Channel m3 45 #N/A 79.05 $3,557Spillway Construction m3 0 #N/A 0 $0Concrete Weir Construction m3 0 #N/A 0 $0OBJECTIVE: FLOOD PITPump Purchase each 1 #N/A 239,000.00 $239,000 Ver 3.0 #4Pipe Puchase and Install m 4000 #N/A 172 $688,000 Ver 3.0 #4Pump Maintenance yr*m 13.0 #N/A 25000 $325,000 Ver 3.0 #4Pump Fuel litre 4,390,000 FLONAS 0.92 $4,016,850 Ver 3.0 #4Access Road m 1,000 #N/A 294 $294,140 Ver 3.0 #4

Subtotal $7,069,879



Open Pit Name: Beartooth Pit # 4


OBJECTIVE: CONTROL ACCESSFence and Signs each 1 FSS 10,000.00 $10,000Berm at Crest m3 26,323 SBSBS 3.98 $104,882Block Roads (20 m ramp length) m3 9,000 RCSS 7.50 $67,500Dozing m3 9,000 DSL 0.95 $8,550OBJECTIVE: CONSTRUCT LITORAL ZONESBlast Rim m3 83,127 RCSS 7.50 $623,449Dozing m3 54,032 DSL 0.95 $51,331Substrate Produce and Place m3 8,313 SCSTS 22.80 $189,512Sediment Berm Produce and Place m3 831 SCSBS 24.21 $20,123Vegetation ha 1 VHFL 4,000.00 $4,000OBJECTIVE: WATER MANAGEMENTOutflow Channel m3 50 #N/A 233.96 $11,698Spillway Construction m3 0 #N/A 0 $0Concrete Weir Construction m3 0 #N/A 0 $0OBJECTIVE: FLOOD PITPump Purchase each 0 #N/A 239,000.00 $0 Ver 3.0 #4Pipe Puchase and Install m 6300 #N/A 505 $3,178,350 Ver 3.0 #4Pump Maintenance yr*m 2.0 #N/A 25000 $50,000 Ver 3.0 #4Pump Fuel litre 533,000 FLONAS 0.92 $487,695 Ver 3.0 #4

Subtotal $4,807,090



Open Pit Name: Fox Pit # 5


OBJECTIVE: CONTROL ACCESSFence and Signs each 1 FSS 10,000.00 $10,000Berm at Crest m3 56,407 SBSBS 3.98 $224,747Block Roads (20 m ramp length) m3 9,000 RCSS 7.50 $67,500Dozing m3 9,000 DSL 0.95 $8,550OBJECTIVE: CONSTRUCT LITORAL ZONESBlast Rim m3 178,128 RCSS 7.50 $1,335,962Dozing m3 115,783 DSL 0.95 $109,994Substrate Produce and Place m3 17,813 SCSTS 22.80 $406,097Sediment Berm Produce and Place m3 1,781 SCSBS 24.21 $43,121Vegetation ha 1 VHFL 4,000.00 $4,000OBJECTIVE: WATER MANAGEMENTOutflow Channel m3 8,300 #N/A 20.5 $170,150Spillway Construction m3 0 #N/A 0 $0Concrete Weir Construction m3 0 #N/A 0 $0OBJECTIVE: FLOOD PITPump Purchase each 1 #N/A 239,000.00 $239,000 Ver 3.0 #4Pipe Puchase and Install m 5000 #N/A 241 $1,205,000 Ver 3.0 #4Pump Maintenance yr*m 18.0 #N/A 25000 $450,000 Ver 3.0 #4Pump Fuel litre 6,530,000 FLONAS 0.92 $5,974,950 Ver 3.0 #4

Subtotal $10,249,072



Open Pit Name: Panda Pit # 6


OBJECTIVE: CONTROL ACCESSFence and Signs each 1 FSS 10,000.00 $10,000Berm at Crest m3 45,126 SBSBS 3.98 $179,798Block Roads (20 m ramp length) m3 9,000 RCSS 7.50 $67,500Dozing m3 9,000 DSL 0.95 $8,550OBJECTIVE: CONSTRUCT LITORAL ZONESBlast Rim m3 142,503 RCSS 7.50 $1,068,770Dozing m3 92,627 DSL 0.95 $87,995Substrate Produce and Place m3 14,250 SCSTS 22.80 $324,878Sediment Berm Produce and Place m3 1,425 SCSBS 24.21 $34,497Vegetation ha 1 VHFL 4,000.00 $4,000OBJECTIVE: WATER MANAGEMENTConnector Channel m3 48,700 #N/A 10.9 $530,830Spillway Construction m3 42000 RC1H 17.8 $747,600Concrete Weir Construction m3 225 CSFH 639.75 $143,944OBJECTIVE: FLOOD PITPump Purchase each 0 #N/A 239,000.00 $0 Ver 3.0 #4Pipe Puchase and Install m 667 #N/A 505 $336,333 Ver 3.0 #4Pump Maintenance yr*m 3.0 #N/A 25000 $75,000 Ver 3.0 #4Pump Fuel litre 992000 FLONAS 0.92 $907,680 Ver 3.0 #4

Costs Split Amongst Three Pits Subtotal $4,527,375



Open Pit Name: Koala North Pit # 7


OBJECTIVE: CONTROL ACCESSFence and Signs each 1 FSS 10,000.00 $10,000Berm at Crest m3 16,922 SBSBS 3.98 $67,424Block Roads (20 m ramp length) m3 9,000 RCSS 7.50 $67,500Dozing m3 9,000 DSL 0.95 $8,550OBJECTIVE: CONSTRUCT LITORAL ZONESBlast Rim m3 138,544 RCSS 7.50 $1,039,082Dozing m3 90,054 DSL 0.95 $85,551Substrate Produce and Place m3 13,854 SCSTS 22.80 $315,853Sediment Berm Produce and Place m3 1,385 SCSBS 24.21 $33,539Vegetation ha 1 VHFL 4,000.00 $4,000OBJECTIVE: WATER MANAGEMENTOutflow Channel m3 0 #N/A 0 $0Drill and Blast Spillway m3 0 #N/A 0 $0Concrete Weir Construction m3 0 #N/A 0 $0OBJECTIVE: FLOOD PITPump Purchase each 0 #N/A 239,000.00 $0 Ver 3.0 #4Pipe Puchase and Install m 667 #N/A 505 $336,333 Ver 3.0 #4Pump Maintenance yr*m 3.0 #N/A 25000 $75,000 Ver 3.0 #4Pump Fuel litre 992000 FLONAS 0.92 $907,680 Ver 3.0 #4




Open Pit Name: Koala Pit # 8


OBJECTIVE: CONTROL ACCESSFence and Signs each 1 FSS 10,000.00 $10,000Berm at Crest m3 43,872 SBSBS 3.98 $174,803Block Roads (20 m ramp length) m3 9,000 RCSS 7.50 $67,500Dozing m3 9,000 DSL 0.95 $8,550OBJECTIVE: COVER/CONTOUR SLOPESBlast Rim m3 53,438 RCSS 7.50 $400,789Dozing m3 34,735 DSL 0.95 $32,998Substrate Produce and Place m3 5,344 SCSTS 22.80 $121,829Sediment Berm Produce and Place m3 534 SCSBS 24.21 $12,936Vegetation ha 1 VHFL 4,000.00 $4,000OBJECTIVE: WATER MANAGEMENTOutflow Channel m3 2,700 #N/A 10.9 $29,430Drill and Blast Spillway m3 0 #N/A 0 $0Concrete Weir Construction m3 0 #N/A 0 $0OBJECTIVE: FLOOD PITPump Purchase each 0 #N/A 239,000.00 $0 Ver 3.0 #4Pipe Puchase and Install m 667 #N/A 505 $336,333 Ver 3.0 #4Pump Maintenance yr*m 3.0 #N/A 25000 $75,000 Ver 3.0 #4Pump Fuel litre 992000 FLONAS 0.92 $907,680 Ver 3.0 #4




Open Pit Name: Lynx Pit # 9

ACTIVITY/MATERIAL Units QuantityCost Code Unit Cost Cost

OBJECTIVE: CONTROL ACCESSFence and Signs each 1 FSS 10,000.00 $10,000Berm at Crest m3 25,070 SBSBS 3.98 $99,888Block Roads (20 m ramp length) m3 9,000 RCSS 7.50 $67,500Dozing m3 9,000 DSL 0.95 $8,550OBJECTIVE: COVER/CONTOUR SLOPESBlast Rim m3 71,251 RCSS 7.50 $534,385Dozing m3 46,313 DSL 0.95 $43,998Substrate Produce and Place m3 7,125 SCSTS 22.80 $162,439Sediment Berm Produce and Place m3 713 SCSBS 24.21 $17,249Vegetation ha 1 VHFL 4,000.00 $4,000OBJECTIVE: WATER MANAGEMENTOutflow Channel m3 45 #N/A 79.05 $3,557Drill and Blast Spillway m3 0 #N/A 0 $0Concrete Weir Construction m3 0 #N/A 0 $0OBJECTIVE: FLOOD PITPump Purchase each 2 #N/A 239,000.00 $478,000 Ver 3.0 #4Pipe Puchase and Install m 2000 #N/A 172 $344,000 Ver 3.0 #4Pump Maintenance yr*m 2.0 #N/A 25000 $50,000 Ver 3.0 #4Pump Fuel litre 813,000 FLONAS 0.92 $743,895 Ver 3.0 #4




Open Pit Name: Jay Pit # 10

ACTIVITY/MATERIAL Units QuantityCost Code Unit Cost Cost

OBJECTIVE: CONTROL ACCESSFence and Signs each 1 FSS 10000 $10,000Berm at Crest m3 68828 SBSBS 3.9843658 $274,234Block Roads (20 m ramp length) m3 9000 RCSS 7.5 $67,500Dozing m3 9000 DSL 0.95 $8,550OBJECTIVE: COVER/CONTOUR SLOPES

OBJECTIVE: WATER MANAGEMENT

OBJECTIVE: FLOOD PITPump Purchase each 0 #N/A 239,000.00 $0 Ver 3.0 #4Pipe Puchase and Install m 200 #N/A 702 $140,400 Ver 3.0 #4Pump Maintenance yr*m 3.0 #N/A 25000 $75,000 Ver 3.0 #4Pump Fuel litre 2390000 FLONAS 0.92 $2,186,850 Ver 3.0 #4

Subtotal $2,762,534



Tailings Impoundment Name: Cell A Pond # 1


OBJECTIVE: COVER TAILINGSRock cover - Upper Zone

Drill Blast Granite Rock m3 369,204 GRCBLS 3.30 $1,218,373Ripp Granite Rock m3 290,089 GRRPS 1.05 $304,593Load/Long Haul/Spread Compact m3 659,293 GRCLHSS 6.35 $4,187,352

Rock cover - Central ZoneDrill Blast Granite Rock m3 106,924 GRCBLS 3.30 $352,849Ripp Granite Rock m3 84,012 GRRPS 1.05 $88,212Load/Long Haul/Spread Compact m3 190,935 GRCLHSS 6.35 $1,212,683

Rock cover - Water Interface ZoneDrill Blast Granite Rock m3 31,846 GRCBLS 3.30 $105,090Ripp Granite Rock m3 25,021 GRRPS 1.05 $26,273Load/Long Haul/Spread Compact m3 56,867 GRCLHSS 6.35 $361,178

VegetatationVegetation Supplies (Seed, Fertilizer Plugs) L.S 1 #N/A 963,000 $963,000Vegetation Equipment Capital Cost L.S 1 #N/A 125,667 $125,667Vegetation Eqquipment Fuel liter 41,667 FLONAS 0.92 $38,125

OBJECTIVE: WEIRExcavate channel (Breach dike, dozer, unfrozen) m3 0 SC3L 8.90 $0Rip-rap m3 0 RR2H 20.65 $0Transition material m3 0 RR2S 21.77 $0

OBJECTIVE: INTERNAL CHANNELExcavate channel m3 30,800 SC3L 8.90 $274,120Rip-rap m3 13,650 RR2H 20.65 $281,873Transition material m3 8,190 RR2S 21.77 $178,288Filter material - sand m3 4,102 SCSH 22.89 $93,890

OBJECTIVE: EXTERNAL CHANNELExcavate channel m3 0 SC3L 8.90 $0

OBJECTIVE: OUTLET DAMExcavate channel (Breach dike, dozer, unfrozen) m3 0 SC3L 8.90 $0Excavate channel (Breach dike, dozer, frozen) m3 0 RC3L 12.70 $0Rip-rap m3 0 RR2H 20.65 $0Transition material m3 0 RR2S 21.77 $0

OBJETIVE: PHASE 1 RECLAMATION PONDExcavate channel m3 0 SC3L 8.90 $0Rip Rap m3 0 RR2H 20.65 $0Granular Cap m3 0 RR2S 21.77 $0Filter material - sand m3 0 SCSH 22.89 $0

Subtotal $9,811,565



Tailings Impoundment Name: Cell B Pond # 2



Drill Blast Granite Rock m3 257,584 GRCBLS 3.30 $850,028Ripp Granite Rock m3 202,388 GRRPS 1.05 $212,507Load/Long Haul/Spread Compact m3 459,972 GRCLHSS 6.35 $2,921,409


Rock cover - Water Interface ZoneDrill Blast Granite Rock m3 0 GRCBLS 3.30 $0Ripp Granite Rock m3 0 GRRPS 1.05 $0Load/Long Haul/Spread Compact m3 0 GRCLHSS 6.35 $0


OBJECTIVE: WEIRExcavate channel (Breach dike, dozer, unfrozen) m3 1,755 SC3L 8.90 $15,621Rip-rap m3 501 RR2H 20.65 $10,346Transition material m3 357 RR2S 21.77 $7,775


OBJECTIVE: EXTERNAL CHANNELExcavate channel m3 105,600 SC3L 8.90 $939,840



Subtotal $9,304,831



Tailings Impoundment Name: Cell C Pond # 3



Drill Blast Granite Rock m3 356,124 GRCBLS 3.30 $1,175,208Ripp Granite Rock m3 279,811 GRRPS 1.05 $293,802Load/Long Haul/Spread Compact m3 635,935 GRCLHSS 6.35 $4,038,999


Rock cover - Water Interface ZoneDrill Blast Granite Rock m3 28,474 GRCBLS 3.30 $93,963Ripp Granite Rock m3 22,372 GRRPS 1.05 $23,491Load/Long Haul/Spread Compact m3 50,846 GRCLHSS 6.35 $322,937


OBJECTIVE: WEIRExcavate channel (Breach dike, dozer, unfrozen) m3 2,093 SC3L 8.90 $18,630Rip-rap m3 594 RR2H 20.65 $12,272Transition material m3 424 RR2S 21.77 $9,230








Tailings Impoundment Name: Cell D Pond # 4



Drill Blast Granite Rock m3 0 GRCBLS 3.30 $0Ripp Granite Rock m3 0 GRRPS 1.05 $0Load/Long Haul/Spread Compact m3 0 GRCLHSS 6.35 $0

Rock cover - Central ZoneDrill Blast Granite Rock m3 0 GRCBLS 3.30 $0Ripp Granite Rock m3 0 GRRPS 1.05 $0Load/Long Haul/Spread Compact m3 0 GRCLHSS 6.35 $0


VegetatationVegetation Supplies (Seed, Fertilizer Plugs) L.S 0 #N/A 0 $0Vegetation Equipment Capital Cost L.S 0 #N/A 0 $0Vegetation Eqquipment Fuel liter 0 FLONAS 0.92 $0

OBJECTIVE: WEIRExcavate channel (Breach dike, dozer, unfrozen) m3 4,982 SC3L 8.90 $44,336Rip-rap m3 1,319 RR2H 20.65 $27,239Transition material m3 952 RR2S 21.77 $20,723

OBJECTIVE: INTERNAL CHANNELExcavate channel m3 0 SC3L 8.90 $0Rip-rap m3 0 RR2H 20.65 $0Transition material m3 0 RR2S 21.77 $0Filter material - sand m3 0 SCSH 22.89 $0




Subtotal $92,298



Tailings Impoundment Name: Cell E Pond # 5






VegetatationVegetation Supplies (Seed, Fertilizer Plugs) L.S 0 #N/A 0 $0Vegetation Equipment Capital Cost L.S 0 #N/A 0 $0Vegetation Eqquipment Fuel liter 0 FLONAS 0.92 $0

OBJECTIVE: WEIRExcavate channel (Breach dam, dozer, frozen) m3 0 RC3L 12.70 $0Rip-rap m3 0 RR2H 20.65 $0Transition material m3 0 RR2S 21.77 $0



OBJECTIVE: OUTLET DAMExcavate channel (Breach dike, dozer, unfrozen) m3 19,197 SC3L 8.90 $170,853Excavate channel (Breach dike, dozer, frozen) m3 6,399 RC3L 12.70 $81,267Rip-rap m3 716 RR2H 20.65 $14,785Transition material m3 8,646 RR2S 21.77 $188,206


Subtotal $455,112



Tailings Impoundment Name: Phase 1 Pond # 6






VegetatationVegetation Supplies (Seed, Fertilizer Plugs) L.S 0 #N/A 0 $0Vegetation Equipment Capital Cost L.S 0 #N/A 0 $0Vegetation Eqquipment Fuel liter 41,667 FLONAS 0.92 $38,125

OBJECTIVE: WEIRExcavate channel (Breach dike, dozer, unfrozen) m3 0 SC3L 8.90 $0Rip-rap m3 0 RR2H 20.65 $0Transition material m3 0 RR2S 21.77 $0



OBJECTIVE: OUTLET DAMExcavate channel m3 0 SC3L 8.90 $0Rip Rap m3 0 RR2H 20.65 $0Granular Cap m3 0 RR2S 21.77 $0Filter material - sand m3 0 SCSH 22.89 $0

OBJETIVE: PHASE 1 RECLAMATION PONDExcavate channel m3 30,000 SC3L 8.90 $267,000Rip Rap m3 3,100 RR2H 20.65 $64,015Granular Cap m3 8,500 RR2S 21.77 $185,037Transition material m3 2,000 SCSH 22.89 $45,778

Subtotal $599,954



Rock Pile Name: Fox WRSA Rock Pile #: 1

ACTIVITY/MATERIAL Units Quantity Cost Code Unit Cost CostOBJECTIVE: WILDLIFE RAMPSFlatten slopes with dozer m3 357,120 DRL 1.05 $374,976OBJECTIVE: WASTE ROCK COVERRock cover - Low Grade Kimberlite

Drill Blast Granite Rock m3 122,304 GRCBLS 3.30 $403,603 Ver 3.0 #1Ripp Granite Rock m3 96,096 GRRPS 1.05 $100,901 Ver 3.0 #1Load/Short Haul/Spread Compact m3 218,400 GRCSHSS 6.04 $1,319,563 Ver 3.0 #1

Rock cover -Waste KimberliteDrill Blast Granite Rock m3 121,800 GRCBLS 3.30 $401,940 Ver 3.0 #1Ripp Granite Rock m3 95,700 GRRPS 1.05 $100,485 Ver 3.0 #1Load/Short Haul/Spread Compact m3 217,500 GRCSHSS 6.04 $1,314,125 Ver 3.0 #1

OBJECTIVE: TOP AREADozer and contour m3 323,800 DRL 1.05 $339,990

Subtotal $4,355,584



Rock Pile Name: Misery WRSA Rock Pile #: 2

ACTIVITY/MATERIAL Units Quantity Cost Code Unit Cost CostOBJECTIVE: WILDLIFE RAMPSFlatten slopes with dozer m3 357,120 DRL 1.05 $374,976OBJECTIVE: WASTE ROCK COVERRock cover - Exposed Metasediment

Drill Blast Granite Rock m3 875,000 GRCBL2S 5.28 $4,620,299Ripp Granite Rock m3 0 GRRPS 1.05 $0Load/Short Haul/Spread Compact m3 875,000 GRCSHSS 6.04 $5,286,711





Rock Pile Name: Panda/Koala Beartooth WRSA Rock Pile #: 3

ACTIVITY/MATERIAL Units Quantity Cost Code Unit Cost Cost % LandOBJECTIVE: WILDLIFE RAMPSFlatten slopes with dozer m3 499,968 DRL 1.05 $524,966OBJECTIVE: WASTE ROCK COVERRock cover - Landfill

Drill Blast Granite Rock m3 55,227 GRCBLS 3.30 $182,249 Ver 3.0 #2Ripp Granite Rock m3 43,393 GRRPS 1.05 $45,562 Ver 3.0 #2Load/Short Haul/Spread Compact m3 197,239 GRCSHSS 6.04 $1,191,707 Ver 3.0 #2

Rock cover - Landfarm & Zones SDrill Blast Granite Rock m3 22,336 GRCBLS 3.30 $73,709 Ver 3.0 #3Ripp Granite Rock m3 17,550 GRRPS 1.05 $18,427 Ver 3.0 #3Load/Short Haul/Spread Compact m3 39,886 GRCSHSS 6.04 $240,989 Ver 3.0 #3

Rock cover -CKRSADrill Blast Granite Rock m3 638,264 GRCBLS 3.30 $2,106,270Ripp Granite Rock m3 501,493 GRRPS 1.05 $526,568Load/Short Haul/Spread Compact m3 1,139,757 GRCSHSS 6.04 $6,886,360

OBJECTIVE: TOP AREADozer and contour m3 517,751 DRL 1.05 $543,639Aerial Seed L.S. 1 #N/A 15000.00 $15,000




Rock Pile Name: Pigeon WRSA Rock Pile #: 4

ACTIVITY/MATERIAL Units Quantity Cost Code Unit Cost CostOBJECTIVE: WILDLIFE RAMPSFlatten slopes with dozer m3 357,120 DRL 1.05 $374,976OBJECTIVE: WASTE ROCK COVERCover - Exposed MetasedimentDozer Slopes m3 550,000 DRL 1.05 $577,500

Place 3 m of Till m3 1,641,000 SB3L 5.10 $8,369,100Drill Blast Granite Rock m3 616,840 GRCBLS 3.30 $2,035,572Ripp Granite Rock m3 484,660 GRRPS 1.05 $508,893Load/Short Haul/Spread Compact m3 1,101,500 GRCSHSS 6.04 $6,655,214

OBJECTIVE: TOP AREADozer and contour m3 0 DRL 1.05 $0




Rock Pile Name: Sable WRSA Rock Pile #: 5

ACTIVITY/MATERIAL Units Quantity Cost Code Unit Cost CostOBJECTIVE: WILDLIFE RAMPSFlatten slopes with dozer m3 571,392 DRL 1.05 $599,962


Subtotal $809,962



Rock Pile Name: Lynx WRSA Rock Pile #: 6

ACTIVITY/MATERIAL Units Quantity Cost Code Unit Cost CostOBJECTIVE: WILDLIFE RAMPSFlatten slopes with dozer m3 142,848 DRL 1.05 $149,990


Subtotal $185,690



Rock Pile Name: JAY WRSA Rock Pile #: 7

ACTIVITY/MATERIAL Units Quantity Cost Code Unit Cost CostOBJECTIVE: WILDLIFE RAMPSFlatten slopes with dozer m3 357,120 DRL 1.05 $374,976OBJECTIVE: WASTE ROCK COVERRock cover - Exposed Metasediment

Drill Blast Granite Rock m3 860,000 GRCBL2S 5.28 $4,541,094Ripp Granite Rock m3 0 GRRPS 1.05Load/Short Haul/Spread Com3 860,000 GRCSHSS 6.04 $5,196,082





Building / Equip Name: All Areas

ACTIVITY/MATERIAL Units Quantity Cost Code Unit Cost CostOBJECTIVE: BUILDING INFRASTRUCTURE DEMOLOTIONPanda/Koala/Beartooth Pit development L.S 1 #N/A 5,498,000 $5,498,000 Ver 3.0 #5Panda/Koala Underground development L.S 1 #N/A 680,000 $680,000 Ver 3.0 #5Fox development L.S 1 #N/A 217,000 $217,000 Ver 3.0 #5Misery development (open pit and underground) L.S 1 #N/A 1,357,000 $3,043,500 Ver 3.0 #5Pigeon development L.S 1 #N/A 85,000 $85,000 Ver 3.0 #5Sable development L.S 1 #N/A 851,500 $851,500 Ver 3.0 #5Lynx development L.S 1 #N/A 65,000 $65,000 Ver 3.0 #5Jay development L.S 1 #N/A 2,019,200 $332,700 Ver 3.0 #5OBJECTIVE: CULVERTS, POWELINES, PIPELINES, BRIDGRES INFRASTRUCTURE DEMOLOTIONCulverts (Excluding Jay) L.S 1 #N/A 402,500 $402,500 Ver 3.0 #5Culverts (Jay) L.S 1 #N/A 35,000 $35,000 Ver 3.0 #5Powerlines (Excluding Jay) L.S 1 #N/A 629,000 $534,650 Ver 3.0 #5Powerlines (Jay) L.S 1 #N/A 94,350 $94,350 Ver 3.0 #5Pipelines (Excluding Jay) L.S 1 #N/A 625,000 $625,000 Ver 3.0 #5Pipelines (Jay) L.S 1 #N/A 487,200 $487,200 Ver 3.0 #5Bridges L.S 1 #N/A 270,000 $270,000 Ver 3.0 #5

Drill Blast Granite Rock m3 110,454 GRCBLS 3.30 $364,497 Ver 3.0 #2Ripp Granite Rock m3 86,785 GRRPS 1.05 $91,124 Ver 3.0 #2Load/Long Haul/Spread Compact m3 197,239 GRCLHSS 6.26 $1,233,997 Ver 3.0 #2OBJECTIVE: RECLAIM PADS, LAYDOWNS, STOCKPILE, & AIRSTRIPScarify Landscape ha 196 SCFYL 4300.00 $842,800 Ver 3.0 #8Establish Vegetation ha 98 VEGS 4000.00 $392,000 Ver 3.0 #8Jay Scarify Landscape ha 17 SCFYL 4,300.00 73,100 Ver 3.0 #8Jay Establish Vegetation ha 8 VEGS 4,000.00 32,000 Ver 3.0 #8Capital Cost Seeding Equipment L.S. 1 #N/A 109969.24 $109,969Drill Blast Granite Rock for Concrete Slabs m3 40,332 GRCBLS 3.30 $133,095Ripp Granite Rock for Concrete Slabs m3 31,689 GRRPS 1.05 $33,274Cover Concrete Slabs m3 72,021 GRCLHSS 6.35 $457,427OBJECTIVE: LINED SUMPSDrill Blast Granite Rock for Concrete Slabs m3 26,878 GRCBLS 3.30 $88,696Ripp Granite Rock for Concrete Slabs m3 21,118 GRRPS 1.05 $22,174Remove liner and place rock cover m3 47,996 GRCLHSS 6.35 $304,833OBJECTIVE: RECLAIM ROADSScarify Access and Haul Roads ha 164 SCFYL 4300.00 $705,200 Ver 3.0 #8Establish Vegetation on Access and Haul Roads ha 82 VEGS 4000.00 $328,000 Ver 3.0 #8Dozer Acess and Haul Road Berms m3 371,158 DSL 0.95 $352,600 Ver 3.0 #8Jay Scarify Access and Haul Roads ha 16 SCFYL 4,300.00 $68,800 Ver 3.0 #8Jay Establish Vegetation on Access and Haul Roads ha 8 VEGS 4000.00 $32,000 Ver 3.0 #8Jay Dozer Acess and Haul Road Berms Road Berms m3 36,211 DSL 0.95 $34,400 Ver 3.0 #8Jay Placement of Esker Material m3 25000 GRCLHSS 6.35 $158,782


OBJECTIVE: LANDFILL FOR INFRASTRCUTURE DEMOLITION WASTE



Water Management : All Areas

ACTIVITY/MATERIAL Units Quantity Cost Code Unit Cost CostOBJECTIVE: BREACH EMBANKMENTBearclaw DamBreach dam, dozer, unfrozen m3 11,202 SC3L 8.90 $99,695Breach dam, dozer, frozen m3 1,977 RC4L 13.50 $26,686Rip-rap m3 512 RR2H 20.65 $10,583Transition material m3 4,503 RR2S 21.77 $98,033King Pond DamBreach dam, dozer, unfrozen m3 4,860 SC3L 8.90 $43,254Breach dam, dozer, frozen m3 0 RC4L 13.50 $0Rip-rap m3 375 RR2H 20.65 $7,744Transition material m3 1,744 RR2S 21.77 $37,960Waste Rock DamBreach dam, dozer, unfrozen m3 67,575 SC3L 8.90 $601,418Breach dam, dozer, frozen m3 0 RC4L 13.50 $0Rip-rap m3 731 RR2H 20.65 $15,100Transition material m3 23,389 RR2S 21.77 $509,150Two Rock DamBreach dam, dozer, unfrozen m3 9,916 SC3L 8.90 $88,255Breach dam, dozer, frozen m3 1,750 RC4L 13.50 $23,624Rip-rap m3 379 RR2H 20.65 $7,821Transition material m3 4,244 RR2S 21.77 $92,377Two Rock DikeBreach dike, dozer, unfrozen m3 1,154 SC3L 8.90 $10,274Rip-rap m3 357 RR2H 20.65 $7,372Transition material m3 251 RR2S 21.77 $5,472Pigeon Outlet Pit BermBreach berm, dozer, unfrozen - 2 areas m3 784 SC3L 8.90 $6,978Rip-rap m3 165 RR2H 20.65 $3,407Transition material m3 379 RR2S 21.77 $8,250East Coffer DamBreach dam, dozer, unfrozen m3 726 SC3L 8.90 $6,460Rip-rap m3 98 RR2H 20.65 $2,013Transition material m3 366 RR2S 21.77 $7,958West Coffer DamBreach dam, dozer, unfrozen m3 135 SC3L 8.90 $1,202Rip-rap m3 48 RR2H 20.65 $981Transition material m3 89 RR2S 21.77 $1,943Breach Jay DikeBreach Jay Dike m3 176000 #N/A 9.48 $1,669,200Turbidity Curtain L.S. 1 #N/A 287,878.00 $484,800Revegetate Shoreline L.S. 1 #N/A 225,000.00 $225,000OBJECTIVE: EKATI MINEAssociated Streams - Re-establish drainageL.S. 1 #N/A 325,000.00 $325,000OBJECTIVE: QUARRY SITERegrade and armor channels L.S. 1 #N/A 333,000.00 $333,000

Subtotal $4,761,011



Chemicals and Soil Contamination: All Areas

ACTIVITY/MATERIAL Units Quantity Cost Code Unit Cost CostHAZARDOUS MATERIALS REMOVALWaste batteries kg 50000 #N/A 0.50 $25,000 Ver 3.0 #9Waste Oils Ship Off Site liters 840000 ORL 0.39 $330,348 Ver 3.0 #9Glycols Ship Off Site litre 24000 #N/A 1.25 $30,000Paints litre 1800 #N/A 0.27 $486Solvents litre 9000 #N/A 0.75 $6,750Explosives allow 2 #N/A 10,000.00 $20,000HAZARDOUS MATERIALS AUDITPhase (1,2,3) ESA (Drilling and Sampling) L.S 1 #N/A 750,000.00 $750,000CONTAMINATED SOIL REMEDIATIONExcavate, Load, Haul to Landfarm m3 35000 SC4L 9.30 $325,500Drill Blast Granite Rock m3 14,000 GRCBLS 3.30 $46,200Ripp Granite Rock m3 11,000 GRRPS 1.05 $11,550Backfill Excavations Granite Rock m3 25,000 GRCLHSS 6.35 $158,782Remediate Soil m3 25,000 CSRL 47.00 $1,175,000Technician and Analysis L.S 1 #N/A 100,000.00 $100,000

Subtotal $2,979,616



Underground Mine Name Panda UG Mine # 1


OBJECTIVE: CONTROL ACCESSPortal - bulkhead and cover entrance L.S. 1 #N/A 64,000 $64,000 Ver 3.0 #9Cap fresh air raise - concrete cap L.S. 2 #N/A 78,843 $157,686 Ver 3.0 #9

Subtotal $221,686



Underground Mine Name Koala UG Mine # 2

ACTIVITY/MATERIAL Unit Qty Cost Code Unit Cost Cost

OBJECTIVE: CONTROL ACCESSPortal - bulkhead and cover entrance L.S. 0 #N/A 64,000 $0Cap fresh air raise - concrete cap L.S. 2 #N/A 78,843 $157,686 Ver 3.0 #9

Subtotal $157,686



Underground Mine Name Koala North UG Mine # 3


OBJECTIVE: CONTROL ACCESSPortal - bulkhead and cover entrance L.S. 1 #N/A 64,000 $64,000 Ver 3.0 #9Cap fresh air raise - concrete cap L.S. 2 #N/A 78,843 $157,686 Ver 3.0 #9

Subtotal $221,686



Underground Mine Name ery Underground UG Mine # 4


OBJECTIVE: CONTROL ACCESSPortal - bulkhead and cover entrance L.S. 0 #N/A 64,000 $0Cap fresh air raise - concrete cap L.S. 1 #N/A 78,843 $78,843 Ver 3.0 #9

Subtotal $78,843



Post-Closure Monitoring & Maintenance: All Areas

ACTIVITY/MATERIAL Units Quantity Cost Code Unit Cost CostOBJECTIVE: MONITORING &REPORTINGClosure Monitoring and Maintenance yrs 5 #N/A 150,000.00 $750,000 Ver 3.0 #6Site Wide (AEMP & SNP)- Primary Reclamarion yrs 3 #N/A 350,000.00 $1,050,000Site Wide (AEMP & SNP)- Closure Monitoring yrs 10 #N/A 175,000.00 $1,750,000Site Wide (AEMP & SNP)- Pit Flooding Program yrs 6 #N/A 30,000.00 $180,000During Pit Flooding - Pit Water Quality Monitoring (SNP) years*pit lake 49 #N/A 20,000.00 $980,000 Ver 3.0 #4Post Flooding - Pit Water Quality Monitoring (AEMP & SNP) years*pit lake 80 #N/A 30,000.00 $2,400,000Panda Diversion Inspections yrs 10 #N/A $1,500 $15,000Geotechnical Inspections (Land) yrs 13 #N/A 60,000.00 $780,000Geotechnical Inspections (Permafrost) yrs 13 #N/A 50,000.00 $650,000Air Quality Monitoring Program (AQMP) yrs 13 #N/A 30,000.00 $390,000Wildlife Effects Monitoring Program (WEMP) yrs 13 #N/A 120,000.00 $1,560,000LLCF Vegetation Monitoring (VMP) yrs 10 #N/A $75,000 $750,000Site Vegetation Monitoring (VMP) yrs 13 #N/A 36,000.00 $468,000Seepage Monitoring Program yrs 13 #N/A 67,500.00 $877,500Archaeology Monitoring Program yrs 6 #N/A $10,000 $60,000Jay Turbity Monitoring LS 1 #N/A 312,000.00 $312,000Pit Flooding Annual Staff (5 Labourers) hrs 34857 lab-uss 40.00 $1,394,300 Ver 3.0 #4




Mobilization: All Areas


MOBILIZE EQUIPMENT *& MATERIALSPipe Shipping m 20,500 #N/A 14 $287,000 Ver 3.0 #4Pipe Shipping (Sable) m 3,700 #N/A 14 $51,800 Ver 3.0 #4Pump Shipping each 5 #N/A 2500 $12,500 Ver 3.0 #4Pump Shipping (Sable) each 1 #N/A 2500 $2,500 Ver 3.0 #4Minor Tools and Equipment (Inlcuding Vegetation) L.S. 1 #N/A 100,000 $100,000Exacavators, 3 L.S. 1 #N/A 37,710 $37,710Dump Trucks, 12 L.S. 1 #N/A 203,052 $203,052Dozers, 3 L.S. 1 #N/A 377,096 $377,096Demolotion Shears, 2 L.S. 1 #N/A 25,140 $25,140Crane, 3 L.S. 1 #N/A 37,710 $37,710*Truck Tires L.S. 1 #N/A 50,000 $50,000DEMOBILIZE EQUIPMENTExacavators, 3 L.S. 1 #N/A 37,710 $37,710Dump Trucks, 12 L.S. 1 #N/A 203,052 $203,052Dozers, 3 L.S. 1 #N/A 377,096 $377,096Demolotion Shears, 2 L.S. 1 #N/A 25,140 $25,140Crane, 3 L.S. 1 #N/A 37,710 $37,710MOBILIZE CAMPReclamation Activities Camp allow 1 #N/A 150,000 $150,000Pit Flooding Camp allow 1 #N/A 75,000 $75,000MOBILIZE WORKERSReclamation Activities Airfare (two flights a week) each 312 DSH7S 9100 $2,839,200Pump Flooding Airfaire (one flight a week) each 0 FLTSS 4,500.00 $0 Ver 3.0 #4Monitoring Airfare (6 flights a year) each 60 FLTSS 4500 $270,000MOBILIZE FUELFuel Freight (Open Pit Pump Flooding) litre 17,458,333 FLMBS 0.22 $3,823,375 Ver 3.0 #4Winter Road Usage (Open Pit Pump Flooding) tonnes 14,525 WRS 111.9277618 $1,625,788 Ver 3.0 #4Fuel Freight (Sable Pit Pump Flooding ) litre 4,390,000 FLMBS 0.22 $961,410 Ver 3.0 #4Winter Road Usage (Sable Pit Pump Flooding) tonnes 3,652 WRS 111.9277618 $408,814 Ver 3.0 #4Fuel Freight (Reclamation Activities Equipment) litre 16,500,000 FLMBS 0.219 $3,613,500Winter Road Usage (Reclamation Activities Equipment) tonnes 13,728 WRS 111.9277618 $1,536,544WORKER ACCOMODATIONSPrimary Reclamation Activities manday 254233 ACCMS 96.00 $24,406,368 Ver 3.0 #4 & #7Pit Pump Flooding manday 0 ACCML 100.00 $0 Ver 3.0 #4INTERIM CARE & MAINTENANCEInterim Care & Maintenance annual 3 #N/A $2,223,639 $6,670,917FINAL CLOSURE PLANPreparation of final Closure Plan L.S. 1 #N/A 1,000,000 $1,000,000PUMP FLOODING AND VEGETATION STAFFPit Flooding Annual Staff (5 Labourers) hrs 81333 lab-uss 40.00 $3,253,367 Ver 3.0 #4Vegetation Labour hrs 29,190 lab-uss 37.49 $1,094,333



Risidual Risks All Areas

ACTIVITY/MATERIAL Units Quantity Cost Code Unit Cost CostRESIDUAL RISK ITEMPanda Diversion Channel L.S. 1 #N/A #N/A 656,803

Subtotal $656,803


ITEM COST CODE UNITS LOW $ HIGH $ SPECIFIED $ COMMENTS

Granite Rock CappingDrill Blast Granite Rock (Remined Rock) GRCBL m3 #NA #NA 3.30Drill Blast Granite Rock (Intact Rock) GRCBL2 m3 #NA #NA 5.28Ripping Granite Rock GRRP m3 #NA #NA 1.05 Using DRL valueLoad/Long Haul/Spread Compact GRCLHS m3 #NA #NA 6.35 Ekati Internal Load/Short Haul/Spread Compact GRCSHS m3 #NA #NA 6.04 Ekati Internal FuelFuel Operating Cost Automotive FLOA litre 0.99 1.39 1.05 Based on internal operating data and including automotive taxFuel Operating Cost Non -Automotive FLONA litre 0.99 1.39 0.92 Based on internal operating data excluding automotive taxFuel Mobilizattion FLMB litre 0.22 0.42 0.22 Based on internal operating data for freight from edmonton to ekati excluding winter roadDozingDoze Rock piles DR m3 1.05 2.40 #N/A LOW cost: doze crest off dumpDoze overburden/Soil piles DS m3 0.95 3.80 #N/A HIGH cost: push up to 300 mExcavate Rock, ControlledRC1 (Drill, blast, load, short haul (<500m) Dump RC1 m3 12.05 17.80 #N/A low - foundation excavation, high - spillway excavationRC1 (Drill, blast, load, short haul (<500m) Dump + spread and compact RC3 m3 12.70 18.40 #N/A LOW Reclaim Default value designated for blasting of frozen core damns and short haulRC1 + long haul + spread and compact RC4 m3 13.50 19.20 #N/A LOW Reclaim Default value designated for blasting of frozen core damns/access ramps and long haulDrill and Blast (Specified Activity) RCS m3 #N/A #N/A 7.50 2004 RCSL value for low specified, blast & doze pit rim )Excavate Rip RapRR1 (Drill, blast, Load Short Haul (<500 m) Dump and Spread + Long Haul RR2 m3 14.20 20.65 21.77 HIGH cost: quarry & place rip rap in channel SPECIFIED for transational material average of sand and rip rapExcavate Soil, ControlledSC1 (Excavate, Load, Short Haul (<500 m), Dump) + Spread and Compact SC3 m3 8.90 14.20 #N/A LOW Reclaim Default value designated for breaching dykes and excavations and short haulSC1 (Excavate, Load, Long Haul (<500 m), Dump) + Spread and Compact SC4 m3 9.30 23.20 #N/A LOW Reclaim Default value designated for breaching dykes and excavations and long haulSC1 (Excavate, Load, Short haul (<500 m), Dump) + Specified activity SCS m3 #N/A 22.89 17.35 SPECIFIED cost: backfill adit with waste rock, High - sand bedding layer for linersProduce and Place Littoral Substrate SCST m3 #NA #NA 22.80 Internal Estimate 2011 EBA $16.27 produce + $ 6.53 average for placement)Produce and Plate Littotal Sediment Berm SCSB m3 #NA #NA 24.21 Internal Estimate 2011 EBA $10.85 produce + $ 13.36 average for placement )Excavate Soil; Low Spec's and QA/QCexcavate/load/short haul + spread and compact SB3 m3 5.10 8.90 Low: non-engineered; High:engineeredScarify Scarify Road SCFY ha 4,300.00 6,030.00 2150 LOW Reclaim Default VegetationHydroseed, Flat VHF ha 4,000.00Siite Wide Vegetation VEG ha 4,000.00Excavate Soil, BulkConstruct and Reshape Berm SBSB m3 3.20 6.30 3.98Concrete workSmall pour, Formed CSF m3 426.50 639.75 #N/A LOW Reclaim value used for Spillway ConstructionSigns and FenceSigns and Fence FS each #NA #NA 10,000.00 Based on internal estimate per pitOilRemove from site OR litre 0.43 1.20 LOW Reclaim Default ValueRemediate on site CSR m3 47.00 146.00 #N/A LOW cost: bio-remediate on-site. HIGH cost: ship off-site to landfil as haz. wasteWinter RoadUsage Rate WR tonnexkm #N/A #N/A 111.93 Calculated from a rate of $0.2907 tonne/km multipled by 385 distance from Yellowknife to EkatiMobilize WorkersDash 7 Flight DSH7 each 4500.00 9100.00 9,100.00 Ekati Cost10 person plane FLTS each 4500.00 9100.00 4,500.00 AANDC Interim Care and Maintenance ValueAccomodationPrimary Reclamation Activities ACCM manday 100.00 175.00 96.00Typical Labour & Equipment Rateslabour - unskilled lab-us $/hr 31.00 43.98 37.49 Specific avergae of high and low RECLAIM values

