AUSTRALIAN VANADIUM PROJECT HYDROGEOLOGICAL ...

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AUSTRALIAN VANADIUM PROJECT

HYDROGEOLOGICAL ASSESSMENT

Prepared for

AUSTRALIAN VANADIUM LIMITED

March 2021

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AQ2 Pty Ltd Level 4, 56 William Street Perth 6000 T: 08 9322 9733 www.aq2.com.au

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Document Status

Version Purpose of Document Author Reviewed By Review Date

A Interim Report EJB DGS Jan 2020

B Updated Report for Referral KLR DGS Nov 2020

C Updated Report KLR DGS Mar 2021

D Final Report KLR DGS Mar 2021

This document has been prepared by AQ2 for the sole use of AQ2 and its client and the document should only be used for the purposes for which it was commissioned and in accordance with the Terms of Engagement for the commission. AQ2 accepts no responsibility for the unauthorised copying or use of this document in any form whatsoever. This document has been prepared using appropriate care, professional expertise and due diligence as requested by the client, or, in the absence of specific requests, in accordance with accepted professional practice. The document is based on information and data generated during this study, provided by the client or other such information available in the public domain that could be reasonably obtained within the scope of this engagement. Unless specified otherwise, AQ2 makes no warranty as to the accuracy of third-party data. The document presents interpretations of geological and hydrogeological conditions based on data that provide only a limited view of the subsurface. Such conditions may vary in space or over time from the conditions indicated by the available data and AQ2 accepts no responsibility for the consequences of such changes where they could not be reasonably foreseen from available data.

Prepared by: AQ2 Pty Ltd (ABN 38 164 858 075) Prepared for: Australian Vanadium Ltd

(ABN 90 116 221 740)

T: (08) 9322 9733 T: (08) 9321 5594

E: [email protected] E: [email protected]

W: www.aq2.com.au W: www.australianvanadium.com.au

Author: Emma Bolton

Reviewed: Duncan Storey

Approved: Duncan Storey

Version: D

Date: March 2021

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TABLE OF CONTENTS

1 INTRODUCTION ......................................................................................................... 1

1.1 Background ...................................................................................................... 1 1.2 Objectives and Limitations .................................................................................. 1 1.3 Topography and Hydrology .................................................................................. 2 1.4 Climate ............................................................................................................ 2 1.5 Geology ............................................................................................................ 2

2 HYDROGEOLOGICAL FIELD INVESTIGATIONS ........................................................... 4

2.1 Geophysical Survey ............................................................................................ 4 2.2 Drilling and Bore Construction ............................................................................. 4 2.3 Hydraulic Testing ............................................................................................... 6

3 HYDROGEOLOGY ...................................................................................................... 10

3.1 Hydrogeological Units ........................................................................................ 10 3.2 Aquifer Parameters ........................................................................................... 11 3.3 Groundwater Levels .......................................................................................... 14 3.4 Groundwater Quality ......................................................................................... 14 3.5 Conceptual Hydrogeological Model and Implications for Mining................................. 15

4 WATER MANAGEMENT ............................................................................................. 18

4.1 Dewatering ...................................................................................................... 18 4.1.1 Project Mine Plan ................................................................................... 18 4.1.2 Dewatering Assessment Methodology ........................................................ 18 4.1.3 Pit Dewatering Requirements ................................................................... 20 4.1.4 Open Pit Dewatering Method .................................................................... 21

4.2 Water Balance .................................................................................................. 22 4.2.1 Water Demand ...................................................................................... 22

4.3 Water Supply ................................................................................................... 22 4.4 Excess Water Management ................................................................................. 23

5 IMPACT ASSESSMENT .............................................................................................. 24

5.1 Regional Drawdown Impact - End of Mining .......................................................... 24 5.2 Mine Closure .................................................................................................... 24

6 CONCLUSIONS & RECOMMENDATIONS .................................................................... 25

6.1 Conclusions...................................................................................................... 25 6.2 Recommendations ............................................................................................ 27

7 REFERENCES ............................................................................................................ 28

Tables

Table 1: Details of the Monitoring and Production Bores ........................................................ 8 Table 2: Hydraulic Test Details ........................................................................................... 9 Table 3: Test Pumping Details ........................................................................................... 9 Table 4: Analysis of Micro-test Data ................................................................................... 12 Table 5: Summary of Estimated Aquifer Permeability ........................................................... 13 Table 6: Groundwater Chemistry Analyses .......................................................................... 17 Table 7: Adopted Mining Schedule for Dewatering Predictions ................................................ 18 Table 8: Calibrated Aquifer Parameters .............................................................................. 19 Table 9: Predicted Dewatering By Pit ................................................................................. 21 Table 10: Predicted Dewatering and Surplus (in kL/d) .......................................................... 23

Figures

Figure 1 Location Map Showing Project Tenements Figure 2 Bore Location Map Figure 3 Geology Map Showing Water Level Contours Figure 4 Expanded Durov Diagram Figure 5 Predicted Dewatering Inflows Figure 6 Modelled Drawdown at End of Mining Figure 7 Modelled Drawdown at Closure

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Appendices

Appendix A: TEM Survey Results Appendix B: Borelogs Appendix C: Hydraulic Testing Plots Appendix D: Water Quality Analyses Appendix E: Numerical Groundwater Modelling

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1 INTRODUCTION

1.1 Background

Australian Vanadium Ltd (AVL) are currently undertaking a Feasibility Study for the Australian

Vanadium Project in the Murchison region of Western Australia.

The Australian Vanadium Project (Project) is located approximately 610 km northeast of Perth and

45 km southeast of Meekatharra, adjacent to the Meekatharra-Sandstone Road. The project extends

along the strike of the orebody and is covered by a series of Exploration Licences; four pits are

proposed (refer Figure 1).

The project will involve open-cut mining to a depth of approximately 240 metres below ground level

(mbgl). Static water levels across the orebody are in the order of 10 mbgl and dewatering of at least

230 m will be required for the deepest pits.

Water will be required for mining and dust suppression purposes. Additionally, the project will involve

crushing and processing of ore and a process water supply will be required. The process water supply

must be low salinity water.

AVL have engaged AQ2 to assist with water management issues relating to dewatering and water

supply for the project. Preliminary assessments were conducted as part of the Pre-Feasibility Study

(AQ2, 2018), before any specific hydrogeological drilling was completed. This report documents the

field investigations, dewatering assessment and impact assessment that have been completed to

date, as part of the Feasibility Study and in support of the Environmental Protection Authority (EPA)

Referral document.

1.2 Objectives and Limitations

The scope of work for this study included:

Determination of dewatering requirements and associated impacts for the life of mine.

Assessment of the water supply potential in the proximity of the project.

Installation of a groundwater monitoring network to allow the collection of baseline data sets

such that the potential impacts of future mining operations can be identified.

Prediction of the impacts of dewatering and mine closure.

The integrated mine water management strategy is pending finalisation of the mine design and

development strategy. Key elements of the strategy will include:

Mining below the water table will require dewatering (the dewatering product is expected to

be brackish to saline).

Where possible, dewatering water will be used for dust suppression and mining operations.

Any surplus dewatering production will be evaporated with the use of water cannons onto

waste dumps.

Freshwater will be obtained from pumping from WestGold mining operations in the area.

This study has focused on characterization of the regional groundwater system, investigation of

dewatering requirements and confirmation of local water supply potential. The study was conducted


based on available site specific data and regional publicly available data including details on

registered water supply bores, geophysical surveys and regional geological mapping. The field

investigation programme was completed in early to mid 2019, and involved installation of

groundwater monitoring bores and hydraulic testing in the potential water supply and orebody areas.

Field investigations in the orebody area were focused in the area of the northern most pit (Pit 3) and

did not include assessment of the additional three pits (Pits 1, 2 and 4) as they were not part of the

original mine design. Results from the hydrogeological investigations in the area of Pit 3 have been

extrapolated to cover the additional pits, located along strike. No timeseries data was collected from

the bore network prior to completing the groundwater modelling.

Obtaining process water supplies from WestGold Mining operations primarily relates to logistics and

agreements between AVL and WestGold and these arrangements are not covered in this technical

report.

1.3 Topography and Hydrology

The project is located in an area of relatively flat topography, with isolated hills. Surface water drains

in a southwesterly direction across the deposit, off the hills to the north, into a main drainage line

which feeds into Lake Annean, approximately 30 km to the north west.

1.4 Climate

The climate is characterised as arid with dry, hot summers and mild winters. The long-term annual

average rainfall for Meekatharra between 1944 and 2019 is 235 mm, with rainfall predominantly

occurring during the summer months. According to the Bureau of Meteorology (BOM) weather station

at Meekatharra Airport (Site 007045), the mean maximum daily temperatures range between 19°C

in July to 38°C in January. High evaporation rates of over 200 mm/month result in a large

environmental water deficit within the area.

1.5 Geology

The orebody is located toward the northern margins of the Archean Yilgarn Craton and the geology

comprises greenstone juxtaposed with granite. Regionally to the north lies the metasedimentary

sequence associated with the Capricorn orogen while to the west lies greenstone/granites of the

Murchison Domain. Basement rocks in the area are characterised by a deep oxidation profile of over

50 m in places. Basement rocks have been peneplaned and over much of the area are covered with

a thin veneer of eluvial sediments.

During the Tertiary, a well-developed drainage system was incised into the basement geology, the

relicts of which are preserved in a series of regional paleochannels. Sedimentary cover can be 50 m

or more where the basement is overlain by paleochannel sediments. Calcrete outcrops can be

associated with these paleochannels and are evident to the south of the orebody area, along the

current drainage line which feeds into Lake Annean (refer Section 3.1). Larger streams associated

with the modern ephemeral drainage pattern also tend to follow the alignment of the paleovalley

system. An airborne time-domain electro- magnetic survey (TEM) completed by DWER and CSIRO

(Bell et al, 2012; Davis & Macaulay et al, 2016) suggests a northwest-southeast trending

paleochannel exists to the south of the deposit, in alignment with the current-day drainage line that

flows to Lake Annean.


The orebody is hosted in mafic, ultramafic and volcanic rocks of the Gabanintha Formation. The

mineralisation is closely associated with a series of massive to disseminated V-Ti-Fe beds, ranging

from a few metres up to 20 to 30 m thick. The orebody is some 20 km in strike length and dips to

the west at an average of 55 - 60 degrees. The orebody is disrupted by a number of cross cutting

structures including dolerite dykes, faults and quartz porphyries.

Over the deposit area, the bedrock is oxidized to various depths:

Complete oxidation and the development of saprolite clay occurs to between around 0 m

and 30 m below ground level. Partial oxidation, forming saprock, occurs below this at depths of between 30 and 70 m

below ground level (mbgl).

Oxidation within individual structures (faults, fractures and veins where dissolution has

occurred) is inferred in drill core to depths of up to 100 m. However, the frequency of such

zones is low.


2 HYDROGEOLOGICAL FIELD INVESTIGATIONS

A preliminary site visit was conducted between 31st July and 2nd August 2018 during which water

levels were measured in mineral drill holes across the orebody area and hydraulic testing (micro-

test pumping) and groundwater sampling was conducted at selected drill holes to provide preliminary

estimates of aquifer properties.

Field investigations were conducted as part of the Feasibility Study between 9th of April and 20th July

2019 and were focused on the assessment of both water supply and dewatering. Dewatering

investigations focused on the area of Pit 3 (the only area included in the proposed development at

that time). Fieldwork comprised the following:

A ground-based geophysical survey to identify drilling targets in the mapped paleochannel

to the south of the orebody.

Exploration drilling and installation of five monitoring bores (two deep and three shallow) to

investigate the water supply potential of the deep and shallow paleochannel sediments to

the southeast of the orebody and to allow baseline and on-going monitoring of the

groundwater system and potential stygofauna in this area.

Exploration drilling and installation of six monitoring bores in the Pit 3 orebody area to

identify aquifers, provide a baseline monitoring network and in some locations, to allow on-

going monitoring of the potential impacts of mining.

Installation and test pumping of one deep production bore in the Pit 3 orebody and one

shallow production bore in the paleochannel area to determine aquifer parameters and

sustainable bore yields.

Hydraulic testing (micro-testing and falling head tests) of newly installed monitoring bores

to provide additional estimates of hydraulic parameters for both the dewatering and water

supply assessments.

Collection of representative water samples from all newly constructed monitoring and

production bores for chemical analysis.

2.1 Geophysical Survey

A ground-based TEM survey was conducted between 5th and 10th March 2019 by Southern

Geoscience Consultants Pty Ltd (SGC), under direct contract to AVL.

Six transects were completed across the mapped paleochannel, over a strike length of approximately

14 km. The locations of the geophysical survey lines are shown in Figure 2, with profile plots of the

TEM data and cross-sections of the conductivity depth inversion (CDI) models presented in

Appendix A.

A channel feature is evident on each of the TEM transects, such that drill sites could be selected to

target the deepest part of each profile (i.e. the paleochannel thalweg). The inferred paleochannel is

also shown on Figure 2.

2.2 Drilling and Bore Construction

The installation of monitoring and production bores was undertaken by Ausdrill Northwest under

direct contract to AVL and supervised by an AQ2 hydrogeologist. Drilling started on 9th April 2019

and was completed on 15th July 2019, with a hiatus of approximately 2 weeks towards the end of


April, due to flooding of access tracks. A combination of dual-rotary (DR) and conventional air-

hammer / down-the-hole hammer (DTH) drilling was used for the entire programme. The type of

ground determined the type of drilling method, with DR generally being used for the Tertiary,

unconsolidated overburden and weathered / fractured bedrock, and DTH being used for competent

bedrock.

For the monitoring bore sites, where the DR method was used, a 241 mm diameter hole was drilled,

whilst DTH drilling was conducted at 191 mm diameter (i.e. 95/8” ND drill-casing with an 8” ND drill

bit). Drill cuttings were collected at 2 m intervals and the holes were logged by the site hydrogeologist.

Whist drilling with air, water returns were measured using a timed-bucket method to determine the

yields from zones of groundwater inflow (i.e. permeable horizons).

Following the drilling, 50 mm ND Class 18 PVC casing was installed to the final depth of the monitoring

hole, with machine-slotted casing installed against the areas where higher yields were intersected

during drilling (i.e. more permeable zones). 1 mm slotted casing was used for the deep monitoring

bores in the paleochannel area and 3 mm slots were used for the shallow monitoring bores, to allow

for stygofauna monitoring. In order to use the remaining 3 mm slotted casing on site, a combination

of 1 mm and 3 mm slots were used to complete the monitoring bores in the orebody area.

Gravel pack was then installed down the bore annulus, progressively retrieving the DR conductor

casing in the process. 1.6 to 3.2 mm graded gravel pack was used where 1 mm slotted casing had

been installed, and 3.2 to 6.4 mm gravel was installed adjacent to the 3 mm slotted casing. A

significant volume of gravel pack was required at Bore 19AVWM02d to fill a cavity at a depth of

114 mbgl. The cavity had formed during drilling due to an interval of pressurised sand being

intersected at this depth; with the removal of the pressurised sand (which rose up inside the DR

casing string), creating an extensive cavity.

A bentonite seal was installed in the bore annulus a few meters above the targeted aquifer, with

gravel also used for backfilling the annulus, above the seal, to the surface. All DR conductor casing

was removed from the drilled holes, with the exception of Bore 19AVWM01 where 125 m of casing

remains in place, due to the failure of the casing during retrieval.

Each bore was completed with headworks, including a concrete surface plinth with a heavy-duty steel

standpipe and locking cap. Once completed, each monitoring bore was developed (airlifted) until the

site hydrogeologist was satisfied the discharge water was free of sediment. The development time

ranged from 1 hour to 6 hours with water samples taken for lab analysis at the end of the airlift

development. During the development of Bore 19AVWM112, gravel pack was found in the airlift

returns and inside the PVC casing string. It is assumed that settlement of the gravel in the bore

annulus has resulted in the 1.6 to 3.2 mm gravel pack being adjacent to, and passing through, the

3 mm slots.

Two production bores were drilled, one shallow bore targeting the shallow Tertiary sediments in the

paleochannel area, and one deep bore targeting the fractured bedrock in the orebody. At the shallow

production bore site only the DR drilling method was used, with a drill diameter of 346 mm (i.e.

13½” ND). At the deep production bore site, a combination of DR and DTH was used to drill to total

depth, with drill diameters being 346 mm and 298 mm respectively (i.e. 13½” ND drill casing with a

12” ND drill bit). 200 mm ND Class 18 PVC casing was installed following the drilling. 1 mm slotted

casing was installed in both the shallow and deep production bores against the zones of high yields


experienced during drilling, with 1.6 - 3.2 mm gravel pack installed in the annulus. A bentonite seal

was installed a few meters above the targeted aquifer, with gravel used to backfill the remaining

annulus to surface. Both bores were completed with headworks, including a concrete surface plinth

with a heavy-duty steel standpipe and locking cap.

Once completed, each production bore was developed (airlifted) until the discharged water was free

from sediment. The development time ranged from 6 hours to 8 hours.

The locations of the installed bores are shown in Figure 2. Bore logs are presented in Appendix B

with bore details summarised in Table 1.

2.3 Hydraulic Testing

Hydraulic testing has been conducted in both the paleochannel and orebody areas, comprising:

micro-pumping tests at selected mineral / geotechnical drill holes (during the preliminary

site visit);

airlift tests and / or falling head tests at the installed monitoring bores; and

test pumping of the two production bores.

Micro-pumping tests were undertaken in 4 geotechnical (diamond) drill holes (GDH904, 911, 912

and 914) and 4 mineral exploration (RC) holes (GRC0161, 165, 169 and 180). The tests were

conducted using a low-discharge pump and pressure transducer to provide high frequency accurate

water level measurements. Both drawdown and recovery measurements were taken during the

micro-testing and the results were analysed using standard curve-fitting analysis methods.

Airlift aquifer tests were undertaken at 19AVWM02s, 02d, 03, 104 and 114 as part of the Ausdrill

Northwest drilling programme. The bores were airlifted for 30 minutes using a poly pipe and

compressor, with an installed pressure transducer / logger recording the water level drawdown and

subsequent recovery.

Falling head tests were undertaken at 19AVWM01, 108 and 113 using a pressure transducer to

measure the rise and fall in water level as water was introduced into the bore. Approximately 60 L

of water was added to each bore to raise water levels as quickly as possible. The water level peak

was obtained from the pressure transducer data and the decline in water levels from this peak was

analysed. Analysis was undertaken using the Bower-Rice method.

The test pumping of the two production bores (19AVWP001 and 19AVWP002) was conducted

between the 3rd of August 2019 and the 12th of August 2019 by Resource Water Group (RWG), in

partnership with Kgalya Services, under direct contact to AVL.

At each bore, a step test (comprising four thirty minute-steps for 19AVWP001 and four sixty-minute

steps for 19AVWP002) and a ~2-day constant rate test were conducted, each followed by monitored

recovery periods. Water levels were recorded manually at the production bore and adjacent

monitoring bore as well as with pressure transducers. All discharge water was transferred via lay-

flat to turkey’s nest dams located between 50 and 250 m from the tested production bores. The

constant rate test at 19AVWP001 (in the paleochannel area) was terminated after 30 hours when

the dam was full. Whilst at 19AVWP001 (targeting the fractured rock aquifer in the orebody area),

as a steady state was reached when pumping at 5 L/s, the abstraction rate was increased to 8 L/s


at the end of the constant rate test for an additional half hour of pumping to determine if the bore

was capable of higher yields.

Details of the conducted hydraulic tests are presented in Tables 2 and 3 with the data plots presented

in Appendix C.


Table 1: Details of the Monitoring and Production Bores

Hole ID Area / Purpose

Easting (GDA94_Z50)

Northing (GDA94_Z50)

Ground Elevation

(mRL)

Top of Casing

Elevation (mRL)

Stick- up (m)

Drilling Method

Drill Depth (m)

Drill Diam (mm)

Cased Depth

Casing ND

(mm)

Screened Depth (m)

SWL (mbTOC) - vertical

depth

SWL (mRL)

Date of SWL

Max Drilling Airlift Yield (L/s)

Completion Airlift Yield

(L/s)

19AVWM01 Paleochannel 666070 7011649 468.00 468.75 0.75 DR 134 241 134 50 98-134 14.14 455 17/06/2019 6.5 0.07

19AVWM02d 661573 7012645 463.00 463.86 0.86 DR 138 241 138 50 114-138 11.65 452 17/06/2019 ~10 5 Area

19AVWM02s Water Supply – 661591 7012641 463.00 463.88 0.88 DR 28 241 28 50* 10-28 7.76 456 17/06/2019 6 1.7

19AVWM03 654653 7014407 458.00 458.83 0.83 DR 28 241 28 50* 4-28 4.00 455 17/06/2019 10 - Regional

Monitoring 19AVWM04 663545 7011754 464.00 464.77 0.77 DR 28 241 28 50* 22-28 8.43 456 17/06/2019 ~10 2

19AVWM104 663778 7015448 469.50 470.34 0.84 DR 0-60

241/191 175 50 7-19, 31-175 13.96 456 17/06/2019 ~10 2.0 DTH 60-175

19AVWM105 663421 7016066 469.00 469.82 0.82 DR 0-84

241/191 178 50 10-16, 28-178 12.49 457 17/06/2019 12 - DTH 84-178

19AVWM108 Orebody Area 663916 7015608 470.00 470.76 0.76 DR DTH

0-34 34-100 241/191 100 50 28-100 12.30 458 17/06/2019 2 0.7

19AVWM112 Dewatering -

664733 7014236 468.00 468.82 0.82 DR 0-88

241/191 151 50 6-54, 60-150 8.32 461 17/06/2019 20 - Monitoring DTH 88-151

19AVWM113 662879 7017174 472.00 472.87 0.87 DR 0-52

241/191 142 50 10-94, 94-142 11.80 461 17/06/2019 2-3 - DTH 52-142

19AVWM114 663427 7015416 467.00 467.92 0.92 DR 0-106

241/191 148 50 10-46, 52-82, 82-

10.32 458 14/07/2019 9 - DTH 106-148 148

19AVWP001

Orebody Area Dewatering –

Test Production Bore

663418 7016082 469.00 469.58 0.58 DR DTH

0-94 94-184 346/298 184 200 94 - 184 15.64 454 15/07/2019 15 10

19AVWP002

Paleochannel Area

Water Supply - Test Production

Bore

663541 7011751 464.00 464.41 0.41 DR 0-28 346 28 200 16-28 8.15 456 15/07/2019 20 -

Co-ordinates from handheld GPS; Elevation from SRTM data EC= electrical conductivity; SWL= static water level. mbTOC = metres below top of casing


Table 2: Hydraulic Test Details

BHID Easting MGA_Z50

Northing MGA_Z50

TOC Elevation

(mRL) Dip Type

SWL at Start of Test Test Type Test Date

mbRP mRL

19AVWM01 666070 7011649 468.75 -90 Mon Bore 14.14 454.61 Falling Head 15/07/19

19AVWM02d 661573 7012645 463.86 -90 Mon Bore 11.66 452.2 Airlift 14/07/19

19AVWM02s 661591 7012641 463.88 -90 Mon Bore 7.80 456.08 Airlift 14/07/19

19AVWM03 654653 7014407 458.83 -90 Mon Bore 4.02 454.81 Airlift 14/07/19





GDH912 663448 7015976 467.6 -61 DDH, open 12.69 454.95 Micro-pump 1/08/2018




GRC161 663754 7015431 467.8 -60 RC, open 12.66 455.15 Micro-pump 1/08/2018



GRC0180 663630 7015909 467.7 -60 RC, open 11.86 455.86 Micro-pump 1/08/2018 Bores 19AVWM04 and 19AVWM105 were not tested as aquifer parameters at these sites were derived from the test pumping of the adjacent production bores. Bore 19AVWM112 was not tested due to the compromised status of the bore.

Table 3: Test Pumping Details

Bore SWL (mbRP)

Step Test Constant Rate Test

Test Date

Step Duration (mins)

Step Discharge Rates (L/s) Test Date Duration

(hrs) Rates (L/s)

Total Drawdown

(m)

Monitoring Bore

Distance from PB

Total Drawdown

(m)

19AVWP001 19.33 9/8/19 30 2, 4, 6, 8 10/8/19 48 5 40.09 19AVWM105 16.2 5.67

19AVWP002 10.12 3/8/19 60 10, 15, 20, 25 4/8/19 30 10 2.25 19AVWM04 4.9 0.59

mbRP = metres below reference point


3 HYDROGEOLOGY

The results of the field investigations described above have been combined with AVL’s drilling data

and all other publicly available hydrogeological reporting for the area, to form a hydrogeological

understanding of the project area. The results from hydrogeological field investigations at Pit 3 have

been extrapolated to cover Pits 1, 2 and 4 where no investigations have been completed to date (i.e.

aquifer parameters and permeable structural features such as the footwall fault have been

extrapolated to the other pits).

3.1 Hydrogeological Units

A 1 to 2 km-wide, paleochannel has been identified from the ground-based TEM, to the south of the

orebody, trending in a northwest-southeast direction. The inferred location of the paleochannel is

shown in Figure 2, together with the locations of the installed monitoring bores and the proposed pits.

A shallow Mixed Aquifer has been encountered over all of the project area comprising calcrete,

silcrete and ironstone gravel with varying clay and sand content. In places (i.e. at 19AVWM04),

intervals of consolidated calcrete exist within this unit. This gravel and calcrete aquifer unit has been

found to be extensive across the paleochannel area to depths of 28 m, intersected by all drill holes

in the area (19AVWM01 to 19AVWM04), with airlift yields ranging between 4 and 12 L/s. This

shallow Tertiary aquifer unit also extends beyond the paleochannel, both to the south, where

outcropping calcrete is evident along the current-day drainage line, and to the north, where recent

drilling has intersected the unit overlying the orebody. In the orebody area, however, the gravel and

calcrete unit is much more variable in thickness, lithology and permeability (indicated by drilling

yields); it is generally thinner (i.e., 0 to 10 m) with yields, if present, of less than 1 L/s (i.e., at Bores

19AVWM104, 105, 108 and 113), although thicknesses of 38 m and 80 m have been recorded at

19AVWM112 and 19AVWM114 (respectively) with yields of 18 L/s and 10 L/s (respectively).

The shallow mixed aquifer includes alluvial sediments and a shallow “paleochannel” associated with

a north-east to south-west tributary drainage flowing towards the main paleochannel. This tributary

drainage crosses Pit 4. This tributary drainage is inferred from both present drainage patterns and

the available TEM survey; there are no drilling data to confirm its nature.

From the recent drilling, underlying the shallow mixed aquifer, the channel infill comprises the

following units:

Clay Aquitard – An upper, 70 m thick, unit of clay with minor sand / gravel horizons.

Although this unit is predominantly comprised of stiff, puggy clay, Bore 19AVWM01

intersected grey-white calcareous clay (i.e. weathered calcrete) between 75 and 98 mbgl.

Basal Sand and Gravel Aquifer – Comprising medium to coarse-grained, angular to sub-

rounded sand and gravel with clasts ranging between 7 and 50 mm in size. Particles are

predominantly composed of quartz, although black shale and lignite clasts are also present.

This unit has been intersected at both 19AVWM01 and 19AVWM02d, at depths of 100 and

105 mbgl respectively, with a thickness of approximately 20 m and airlift yields ranging

between 6.5 and 10 L/s.


From the recent drilling in the area of the orebody (i.e. outside of the limits of the paleochannel

sediments), three main hydrogeological units have been identified, underlying the shallow mixed

aquifer (where present). These comprise:

Fractured Rock Aquifer – As evident from the yields at depth (ranging between 4 and

10 L/s) at Bores 19AVWM104, 105, 112 and 114 and 19AVWP001, increased (secondary)

permeability occurs as a result of fracturing and faulting between depths of 100 and

180 mbgl. From the structural mapping for the orebody area, numerous small faults cross-

cut the deposit and may be responsible for zones of increased permeability. However, it is

anticipated that the above-listed bores may all intercept a larger northwest-southeast

trending fault (i.e. coincident with the strike of the deposit), possibly associated with the

footwall of the orebody. The aquifer associated with the fault zone is assumed to extend

along the strike of the orebody into all pits. There is a cross cutting fault between Pits 1 and

4 which is assumed to result in some dislocation of the aquifer / orebody.

Unfractured Ore / Bedrock – Where there is no (or minimal) fracturing / faulting the

permeability of the bedrock in the project area (including the orebody) is anticipated to be

low. This is evident from many of the micro-tested RC and diamond drill holes as well as

Bores 19AVWM108 and 113.

A Saprock / Transition zone – This weathered basement unit is evident from the recent

hydrogeological drilling and has been mapped (as indicated by the base of oxidation) by AVL

across the orebody area. This saprock / transition zone has an increased permeability by

comparison to the underlying fresh bedrock, although hydraulic properties may vary laterally

due to changes in bedrock composition and oxidation characteristics.

3.2 Aquifer Parameters

A summary of the aquifer parameters derived from the 2018 and 2019 hydraulic testing are

presented in Tables 4 and 5, respectively. The permeability estimates for the shallow Tertiary aquifer

range from 0.2 to 38 m/d, with higher permeabilities evident in the paleochannel area, rather than

the orebody area. The basal sand and gravel of the paleochannel is estimated to have a permeability

ranging between 0.7 and ~3 m/d.

Although no bores were specifically completed in the either the unfractured bedrock or the saprock /

transition zone, the hydraulic testing of the lower yielding bores (i.e. Bores 19AVWM108 and 113, as

well as the majority of the tested RC and diamond holes) allow aquifer parameters for these combined

units to be derived. As such, the estimated permeabilities for the unfractured bedrock and the

saprock / transition zone ranges between 0.001 and 0.035 m/d. The more permeable, faulted /

fractured rock aquifer in the orebody has a derived permeability ranging between 0.2 and 3.3 m/d.


Table 4: Analysis of Micro-test Data

BHID

T m2/day K m/day

Lithology Representative Geology

Drawdown (Cooper‐

Jacob)

Recovery (Cooper‐

Jacob) Drawdown (AQTESOV)

Drawdown (Cooper‐

Jacob)

Recovery (Cooper‐

Jacob)

GDH912 0.6958 0.6958 0.6147 0.0045 0.0045 10% MMT / 15% MMZ / 30% GAB / 30% SAP Mafic / Clay

GDH911 0.3214 0.3643 0.2906 0.0026 0.0029 30% MMT / 30% MMZ / 15% GAB / 15% SAP Ore

GDH914 0.4886 0.3247 0.4649 0.0037 0.0024 15% MMT / 5% UAU / 5% GAB / 40% SAP / 20% MMZ / 2% QV Clay

GDH904 0.6181 1.1538 0.4817 0.0068 0.0127 40% GAB / 5% QA / 20% MMZ / 10% SCH / 15% DOL / 10% GA Mafic

GRC161 1.3744 7.0439 1.365 0.0115 0.0592 5% MMT / 55% CLY / 10% UAU / 30% GAB Clay

GRC0165 0.5013 8.0209 0.5051 0.0042 0.0674 20% MMT / 60% CLY / 15% UAU / 10% GAB Clay

GRC0169 0.3147 0.2697 0.2789 0.0067 0.0057 50% MMT / 50% CLY Ore / Clay

GRC0180 52.606 56.363 52.63 0.5261 0.5636 20% MMT / 80% CLY Clay


Table 5: Summary of Estimated Aquifer Permeability

Test Bore Screened Aquifer

Aquifer Thickness (m) Test Analytical Method Monitoring Bore Transmissivity

(m2/d)

Hydraulic Conductivity

(m/d) Comments

19AVWM108 Orebody No Aquifer

156 Falling Head Bower‐Rice

4.368 0.028 Early Time 0.156 0.001 Late Time

19AVWM113 132 4.62 0.035 Early Time 0.264 0.002 Late Time

19AVWM114 Orebody Shallow Aquifer 12 Airlift Cooper‐Jacob

3.84 0.32 Early Time

2.52 0.21 Late Time

19AVWM104

Orebody Deep Aquifer

24 Airlift Cooper‐Jacob 19.2 0.8 Early Time 4.8 0.2 Late Time

19AVWP001 24

SRT Logan 19AVWP001

13.2 0.55 12.48 0.52 11.76 0.49 11.76 0.49

CRT

Theis 19AVWP001 14.64 0.61 Early Time 19AVWM105 79.2 3.3 Early Time

Theis Recovery 19AVWP001 16.8 0.7 Late Time 19AVWM105 40.8 1.7 Early Time

Cooper‐Jacob 19AVWP001 12 0.5 Early Time 19AVWM105 38.4 1.6 Late Time

Fractured Rock 19AVWP001 14.16 0.59 Early Time 19AVWM105 57.6 2.4 Early Time

19AVWPM02s

Shallow Aquifer 12

Airlift Cooper‐Jacob

9.6 0.8 Early Time

52.8 4.4 Late Time

19AVWM03 34.8 2.9 Early Time 84.12 7.01 Late Time

19AVWP002 SRT Logan 19AVWP002

504 42 438 36.5

392.4 32.7 355.2 29.6

CRT Hantush for leaky Aquifer 19AVWM04 456 38 Early Time

19AVWM02d

Paleochannel Aquifer

22 Airlift Cooper‐Jacob 63.36 2.88 Early Time

15.84 0.72 Late Time

19AVWM01 3 (Steel casing stuck In Ground

Blocking aquifer) Falling Head Bower‐Rice

1.005 0.335 Early Time

0.024 0.008 Late Time


3.3 Groundwater Levels

Recorded water levels from DWER’s database, together with NASA’s SRTM data for bore elevations,

have been combined with recently recorded water levels to develop estimated groundwater contours

for the area in and around project (Figure 3).

The water table elevation is estimated to range between approximately 470 mRL at Mt Yagahong to

the northeast of the deposit, to 455 mRL in the paleochannel. The overall flow direction across the

project area is to the southwest, towards the paleochannel, and then (north) west along the

paleochannel, to Lake Annean.

The depth to groundwater is shallow in the lower lying areas (i.e. approximately 5 to 10 mbgl) and

increases with elevation. Measured depths to water on the deposit (in the vicinity of Pit 3) are

between 10 and 15 mbgl; the water table in the deposit is at around 458 mRL.

The water levels recorded at 19AVWM02d are approximately 4 m lower than the adjacent shallow

bore (19AVWM02s), indicating the shallow and deep aquifers are hydraulically isolated by the

intervening clay aquitard. Notwithstanding, all groundwater levels in the paleochannel area are

relatively shallow.

3.4 Groundwater Quality

Groundwater quality data is available both from the analysis of collected water samples and from

field readings of salinity during drilling (i.e. with depth). A total of 19 samples have been collected

and analysed by SGS Australia (a NATA accredited laboratory) for major cations, anions and basic

water quality parameters. Seven samples were collected from the micro-testing of existing mineral /

geotechnical drill holes (i.e., composite samples for the open holes), eleven from the development of

recently installed monitoring and production bores (with samples being representative of the screened

aquifer interval) and two from the end of the constant rate tests (again, representative of the

screened aquifer interval).

The results of the hydrochemical analyses are summarised in Table 6 and are plotted on an Expanded

Durov Diagram, in Figure 4. Laboratory reports are presented in Appendix D.

Across the shallow and deep aquifer units in both the paleochannel and orebody areas, the

groundwater is neutral to mildly alkaline, with pH values for all collected samples ranging between

7.0 and 8.2, and samples from the shallow bores in the paleochannel area ranging between 7.9 and

8.2. As shown in the Expanded Durov Diagram (Figure 4), the groundwater across the project area

(for all aquifer types) is sodium and chloride dominant (indicative of an end point (“older”) water).

This suggests the groundwater has been subjected to evapotranspiration and / or mineral dissolution

since it was recharged.

The groundwater salinity across the project area is variable, ranging from brackish to hypersaline.

In the vicinity of the paleochannel, the electrical conductivity (EC) of the groundwater in the shallow

aquifer generally ranges between 4,400 and 19,000 µS/cm. At bore 19AVWM01, however, a reading

of 30,000 µS/cm was recorded; this may be a result of the bore being located upgradient of an inflow

of fresher groundwater from the northeast (refer to Figures 2 and 3). In the basal aquifer, EC readings

of around 180,000 µS/cm have been recorded at both 19AVWM01 and 19AVWM02d.


In the orebody area, the shallow groundwater is slightly fresher, with EC readings ranging between

2,500 and 5,200 µS/cm. However, in Bores 19AVWM104, 105, 112, 114 and 19AVWP001, at depths

of approximately 100 m (where zones of increased permeability have been intersected), salinities of

~250,000 µS/cm have been recorded. In the lower yielding bores of the orebody area (i.e.

19AVWM113 and 108) the groundwater at depth is brackish, as opposed to hypersaline; with EC

readings of 3,300 and ~29,000 µS/cm respectively). At Bore 19AVWM113, the lower salinity is most

likely due to its location adjacent to an ephemeral creek which may provide recharge to the aquifer

locally. Whilst at 19AVWM108, this may be indicative of the “background” groundwater salinity of

the area, with the higher salinity readings in the higher yielding bores, being evident of hypersaline

groundwater associated with the fault zones.

3.5 Conceptual Hydrogeological Model and Implications for Mining

Key points of the conceptual hydrogeological model (based on available data) with respect to the

proposed mining are as follows:

Regionally, the groundwater system appears to be influenced by two main aquifer systems:

o A shallow Tertiary aquifer (comprising calcrete and alluvium) which is present, in

varying thicknesses, over the lower-lying ground (and includes alluvium in the

tributary channel crossing Pit 4).

o A deep paleochannel aquifer, to the south of the orebody, comprising medium to

coarse-grained sand, gravel and cobbles. This aquifer is closest to Pit 1.

In the paleochannel area, the two aquifer units are hydraulically isolated by an intervening

unit of approximately 70 m of low permeability clay.

Regional groundwater flow converges on the paleochannel and then flows along the channel

to the west and north (towards Lake Annan).

The shallow Tertiary aquifer, in the vicinity of the paleochannel, offers a target to develop a

water supply borefield, if required after years 7 to 13 of mining when the dewatering water

surplus may diminish. In this area (i.e. to the south of the orebody), the aquifer is

approximately 15 m thick, with permeability ranging between 1 and 38 m/d and groundwater

salinity (measured as EC) generally ranging between ~4,000 and 20,000 µS/cm.

The basal paleochannel aquifer is approximately 20 m thick, occurring at approximately

100 mbgl. Derived permeability values for this aquifer range between 0.7 and ~3 m/d

although groundwater is hypersaline, with EC values of 180,000 µS/cm recorded. Although

not suitable for process water supply purposes, this aquifer could be targeted for the disposal

(i.e. re-injection) of excess, hypersaline water (from dewatering), should this be required.

However, it should also be noted the relatively shallow depths to water would result in limited

ability to inject under gravity and therefore many bores may be required if surplus volumes

were large.

The basal paleochannel aquifer also offers an alternative source of dust-suppression and

mining water for later in the mine life when dewatering may reduce.

Groundwater levels range between 470 mRL northeast of the deposit to 450 mRL in the

paleochannel area.

Although the Tertiary shallow aquifer extends over the orebody area, it is generally less than

10 m thick, except:


o in the southwest (i.e., at 19AVWM0112 and 114) where thicknesses of up to 80 m

have been intersected;

o over the tributary channel that crosses Pit 4, where an alluvial thickness of up to

50 m is inferred.

Although the bedrock (inclusive of the ore) in the vicinity of the orebody, is anticipated to

be of low permeability, there are local aquifers within the deposit comprising:

o A fractured rock aquifer occurring at depths of between 100 and 180 mbgl with

estimated permeability ranging between 0.2 and 3.3 m/d and groundwater salinity

(EC) of up to 250,000 µS/cm. The fractured rock is inferred to be associated with a

major fault which extends along the strike of the deposit (potentially associated with

the footwall).

o A weathered saprock / transition zone aquifer, underlying the shallow Tertiary

aquifer (if present) and occurring to depths of up to 70 mbgl. Anticipated to have

slightly increased permeability from the competent bedrock, with assumed

permeability values ranging between 0.005 and 0.05 m/d.

At Pit 3, groundwater on the deposit occurs at 458 mRL which is between 10 and 15 mbgl.

Dewatering will be required when mining below this depth. It is assumed this depth is

representative of the additional pits (although future drilling will be required to confirm this.

Although the groundwater is brackish in the shallow aquifer units over the orebody (with EC

ranging between 2,500 and 5,200 µS/cm), and potentially within the unfractured bedrock

at depth (up to an EC of 29,000 µS/cm), it is hypersaline (EC ~250,000 µS/cm ) within the

higher permeability fractures / faults at depth. As groundwater inflow to the proposed pit

will be dominated by the higher permeability zones, the dewatering discharge will become

hypersaline as the pit depth progresses (or as soon as the main fault zone(s) are intercepted

by mining).


Table 6: Groundwater Chemistry Analyses

Area Orebody Area - Bores Orebody Area – RC & Diamond Drill Holes

Bore 19AVWM104 19AVWM105 19AVWM108 19AVWM112 19AVWM113 19AVWP001 19AVWP001 GDH904 GDH911 GDH912 GDH914 GRC161 GRC0169 GRC0180

Analyte Name

Units

Sample Date 29/5/2019

3/6/2019

23/5/2019

15/6/19

15/6/19

8/7/2019

12/8/2019

31/7/18

2/8/18

1/8/18

2/8/18

1/8/18

2/8/18

1/8/18 Reporting

Limit pH pH Units 0.1 7.3 7.2 8.1 7.8 7.9 7.3 7.0 7.4 7.7 7.7 7.7 7.8 7.8 7.9

Conductivity @ 25 C µS/cm 2 170000 180000 29000 16000 2800 170000 150000 31000 4400 9400 6700 5200 2300 2600

TDS Dried at 175-185°C mg/L 10 160000 170000 18000 9400 1500 120000 150000 18600* 2640* 5640* 4020* 3120* 1380* 1560*

Bicarbonate Alkalinity as HCO3 mg/L 5 100 82 230 260 310 93 100 120 280 270 220 220 290 260

Carbonate Alkalinity as CO3 mg/L 5 <5 <5 <5 <5 <5 <5 <5 <1 <1 <1 <1 <1 <1 <1

Hydroxide Alkalinity as OH mg/L 5 <5 <5 <5 <5 <5 <5 <5 - - - - - - -

Total Alkalinity as CaCO3 mg/L 5 83 67 190 210 260 76 83 97 230 220 180 180 240 210

Sulphate, SO4 mg/L 1 14000 15000 2000 170 1100 18000 16000 2200 310 660 580 390 140 180

Chloride, Cl mg/L 1 84000 86000 9200 550 4400 76000 75000 10000 1100 2800 1900 1400 470 550

Calcium, Ca mg/L 0.2 760 760 330 160 81 680 690 440 93 92 94 110 77 62

Magnesium, Mg mg/L 0.1 5700 6000 890 150 110 5300 4900 1100 160 250 170 180 87 85

Potassium, K mg/L 0.1 2200 2600 160 130 3.7 2500 2100 230 11 55 25 25 13 12

Sodium, Na mg/L 0.5 43000 47000 4500 2700 310 43000 41000 4700 570 1600 750 690 260 350

Area Paleochannel Area

Bore 19AVWM01 19AVWM02s 19AVWM03 19AVWM04 19AVWP002

Analyte Name

Units

Sample Date

27/4/2019

14/5/2019

15/5/2019

18/5/2019

13/7/2019Reporting Limit

pH pH Units 0.1 7.2 8.0 8.2 7.9 7.9

Conductivity @ 25 C µS/cm 2 180000 12000 9200 19000 15000

TDS Dried at 175-185°C mg/L 10 140000 7200 5000 12000 8300

Bicarbonate Alkalinity as HCO3 mg/L 5 58 230 300 140 130

Carbonate Alkalinity as CO3 mg/L 5 <1 <1 <5 <5 <5

Hydroxide Alkalinity as OH mg/L 5 - - <5 <5 <5

Total Alkalinity as CaCO3 mg/L 5 47 190 240 110 110

Sulphate, SO4 mg/L 1 19000 800 460 1100 850

Chloride, Cl mg/L 1 88000 3500 2700 7000 4200

Calcium, Ca mg/L 0.2 840 180 110 330 250

Magnesium, Mg mg/L 0.1 6400 390 220 560 400

Potassium, K mg/L 0.1 2800 67 66 120 94

Sodium, Na mg/L 0.5 46000 1600 1500 3100 2300


4 WATER MANAGEMENT

4.1 Dewatering

4.1.1 Project Mine Plan

The dewatering assessment has been based on a mine plan that includes four pits (Pits 1,2, 3 and 4).

Mining will commence in the southern most pit (Pit 1). The mine will operate for 25 years, with each

pit commencing and finishing at different stages over the project life. Final pit depths will range from

230 mRL to 360 mRL (i.e. to approximately 240 mbgl) and rest water levels across the orebody are

approximately 458 mRL (10 to 15 mbgl). Mining will occur at depths of between 100 m and 230 m

below the regional water table. The adopted mining schedule is summarised in Table 7; this schedule

was provided by AVL (0624_AVL_Face-Pos_V6.1_200814).

Table 7: Adopted Mining Schedule for Dewatering Predictions

Year Deepest Mining Elevation (mRL)

Pit 1 Pit 2 Pit 3 Pit 4 1 420 400 - - 2 410 380 - - 3 380 380 450 - 4 350 380 430 - 5 350 360 400 - 6 350 340 370 - 7 350 320 370 - 8 350 320 370 - 9 350 320 370 - 10 350 310 370 - 11 350 350 460 12 330 340 460 13 330 320 460 14 330 310 460 15 330 290 450 16 330 290 430 17 330 290 420 18 330 290 410 19 330 280 380 20 330 270 360 21 330 260 - 22 330 240 - 23 330 230 - 24 300 230 - 25 300 230 -

4.1.2 Dewatering Assessment Methodology

A numerical groundwater model has been developed for the project area to make a preliminary

assessment of the following:

Predicted groundwater inflows to the open pits over the life of the mine.

The regional drawdown impact of pit dewatering at the end of mining.

The potential for the lower aquifer of the Lake Annean paleochannel to be used to manage

excess dewatering, in excess of the project water demand, via Managed Aquifer Recharge

(MAR) and any associated water level changes.


The long term behaviour of the final pit voids once mining is complete, including the time

taken for recovery to post mining or equilibrium levels and regional drawdown associated

with the final mine voids.

Details of the model set up are presented in Appendix E; key points of note are as follows:

The model extent includes the mine area and the Lake Annean paleochannel and tributaries.

Seven model layers are used to represent the mine area and the lower aquifer, clay aquitard

and upper aquifer of the Lake Annean paleochannel and tributaries.

Regional groundwater flows are simulated, with inflow included from the upstream (i.e., from

the northeast, southwest and southeast) and groundwater outflow to the northwest (i.e.,

along the main paleochannel towards Lake Annean).

The model has been calibrated to steady state water level conditions (i.e., regional water

levels). A summary of the calibrated aquifer parameters is presented in Table 8. There are

no transient data for calibration and so adopted storage and specific yield parameters are

“typical values”.

Table 8: Calibrated Aquifer Parameters

Aquifer Unit Layer

Horizontal Hydraulic

Conductivity (m/d)

Vertical Hydraulic

Conductivity (m/d)

Specific Yield (%) Storage

Shallow Mixed Aquifer Lake Annean Paleochannel 1 20 2 7.5 NA*

Shallow Mixed Aquifer Paleochannel Tributaries 1 1 - 5 0.1 to 0.5 7.5 NA*

Basement 1 0.1 0.01 1.0 NA*

Orebody 1 1.0 0.1 2 NA*

Fault 1 to 6 0.1 0.1 0.01 0.00005**

Shallow Mixed Aquifer Lake Annean Paleochannel 2 10 1 7.5 0.00005

Shallow Mixed Aquifer Paleochannel Tributaries 2 1 - 5 0.1 to 0.5 7.5 0.00005

Basement 2 0.05 0.005 0.1 0.00001

Orebody 2 0.01 0.001 2 0.00005

Confining Clay - Lake Annean Paleochannel and Tributaries 3 & 4 0.001 0.00001 6 0.00005

Basement 3 0.05 0.005 0.1 0.00001

Orebody 3 & 4 0.005 0.0005 1 0.00005

Basement 4 0.005 0.0005 0.1 0.00001

Deep Aquifer - Lake Annean Paleochannel and Tributaries 5 10 1.0 15 0.00005

Basement 5 to 7 0.0001 0.0001 0.05 0.00001

Orebody 5 & 6 0.005 0.00005 0.1 0.00005

* Modelled aquifers are assumed to be unconfined in the upper most model layer (layer 1). ** Confined storage coefficient specified in layers 2 to 6 only as the fault is modelled as an unconfined aquifer in model layer 1.


4.1.3 Pit Dewatering Requirements

The predicted inflow rates over the 25-year mine life are presented in Figure 5 and summarised by

pit in Table 9. The results of the dewatering assessment can be summarised as follows:

Predicted mine dewatering is initially high as paleochannel sediments are intersected in Pit 2

but decrease as each pit goes into lower permeability bedrock.

o Dewatering for the first year is approximately 8,000 kL/d (92 L/s).

o Dewatering of between 4,000 kL/d (45 L/s) to 5,000 kL/d (60 L/s) between years 2 and 6.

o Dewatering volumes continue to decrease from 3,000 kL/d (35 L/s) at year 7 to 1,500 kL/d (18 L/s) by year 25.

The distribution of permeability within the fractured rock aquifer may be quite variable. In

practice, this means increases in dewatering are likely to be concentrated over permeable

horizons and this level of discretization cannot be included in the model.

The dewatering estimates take no account of the impact of cross-cutting dolerite and gabbro

dykes which may be of lower permeability and compartmentalise the orebody.

In low permeability rocks, the area affected by dewatering does not extend far from the

dewatering stress (i.e. far from pit wall into the aquifer) and the hydrostatic pressure behind

the pit walls is expected to be high. This may affect wall stability, particularly where the high

pressure corresponds with geomechanical failure surfaces. Subject to geotechnical analysis,

depressurisation of the pit walls may be required, at least in susceptible areas.

It is anticipated that dewatering discharge may initially be brackish; potentially for the first

two years of mining. However, as the mining depth progresses and / or once the higher

permeability fault zones are intersected, the dewatering production may become saline (or

hyper saline), with the fault zones anticipated to comprise 25 to 40% of groundwater inflow

to the pit.


Table 9: Predicted Dewatering By Pit

Year Pit 1

Dewatering (kL/d)

Pit 2 Dewatering

(kL/d)

Pit 3 Dewatering

(kL/d)

Pit 4 Dewatering

(kL/d)

Total Dewatering

(kL/d) 1 3849 4149 0 0 7998

2 1966 1936 0 0 3902

3 1905 1467 1894 0 5266

4 1706 1256 1273 0 4236 5 1369 1257 1880 0 4505

6 1262 1220 1387 0 3868

7 1180 977 710 0 2866

8 1113 904 618 0 2635

9 1058 847 559 0 2464

10 1014 823 517 0 2354

11 976 0 1002 0 1978 12 1154 0 693 0 1848

13 1023 0 723 0 1746

14 1029 0 598 0 1627

15 1021 0 617 0 1638

16 929 0 555 1310 2794

17 883 0 545 701 2129

18 830 0 531 623 1985 19 783 0 550 728 2061

20 764 0 557 649 1970

21 764 0 537 0 1301

22 804 0 535 0 1338

23 792 0 519 0 1310

24 949 0 500 0 1448

25 832 0 489 0 1321

4.1.4 Open Pit Dewatering Method

Based on the initially high dewatering estimates for the first year of mining and variability of

groundwater inflows to each pit, dewatering of the open pits would be best achieved through a

combination of:

Dewatering bores which can be used to dewater the higher permeability shallow aquifer

sediments associated with the large groundwater inflow volumes at the initiation of mining.

Dewatering bores should also target the permeable structure that is inferred to run along

the footwall of the pit. Bores should be located on the pit crest at either end of the pit with

additional bores along strike and within the pit (if they can be accommodated from mining

logistics).

In-pit sump pumping to remove groundwater inflows from lower permeability units. The

mine plan should therefore allow for the presence of sumps within the pit and temporary

drains across the pit floor to direct groundwater to the sumps.

Sump pumping will not allow any dewatering freeboard which means mining will be affected by:

Rises in groundwater levels following rainfall events that may contribute to inundation of the

lower-benches; and

Wet blasting will be required on lower active benches.


Following the dewatering of the shallow aquifer, sump pumping may continue to be effective for the

life of mine. Although dewatering bores similar to, and including, 19AVWP01 could also be used to

target and dewater the higher permeability fault zone(s). This would offer the advantage of advanced

dewatering and increased dewatered free-board.

Based on test pumping of 19AVWP01, a recommended pumping rate of 8 L/s has been derived (refer

Appendix C). However, it should be noted that the sustainability of pumping from a fractured rock

aquifer and its effectiveness for dewatering is uncertain as it depends on the connectivity and extent

of the fractures / faults. If the orientation of the permeable fault(s) becomes well understood, these

bores could potentially be sited outside the pit areas to avoid the logistical difficulties of in-pit bores

(i.e. mining through and recovering them).

Dewatering infrastructure should be designed to accommodate the likely inflow estimate (presented

in Table 9), with additional capacity for surface water runoff.

4.2 Water Balance

4.2.1 Water Demand

The mining and dust suppression (i.e. low-quality) water demand has been estimated by AVL, at

between 0.83 and 0.98 GL/a (2,300 to 2,700 kL/d) with the breakdown of water use as below:

Roads (dust suppression) 0.67 GL/annum (~ 1,835 kL/d)

Mining, wet season 0.16 GL/annum (~440 kL/d)

Mining, dry season 0.31 GL/annum (~850 kL/d)

4.3 Water Supply

Although initial inflows into the pit may be brackish, it is assumed that all mine dewatering is saline

or hypersaline. As such, dewatering will be used to meet mine and dust-suppression water

requirements only.

The range in water demand and the predicted dewatering are shown in Figure 5. Table 10 shows the

balance between dewatering production and low-quality water demand. Key points of the water

balance are summarised below:

From year 1 to 10 and year 16 of mining, groundwater inflows exceed the demand for water

associated with mining activities, meaning excess water will need to be disposed of (refer

Section 4.4).

Following the dewatering of higher permeability zones after year 7, groundwater inflows

decrease and the demand for low quality water exceeds mine inflows. This shortfall is

relatively minor (~4.5 L/s on average) and could be made up by either:

o Using fresh quality water from WestGold pits for mining activities.

o Pumping from the adjacent Lake Annean paleochannel aquifer.

o Adjusting the need for mining related water (i.e. reduce the volume needed for dust

suppression).

The on-site mineral concentrator requires high quality water which will be sourced from existing

WestGold mine voids and mining operations. The logistics and agreements to manage the supply of

water from WestGold to the Australian Vanadium Project, are not covered in this report.


Table 10: Predicted Dewatering and Surplus (in kL/d)

Year Predicted

Dewatering (kL/d)

Water Demand (kL/d) Surplus (kL/d)

Minimum Maximum Minimum Maximum 1 7998 2274 2685 5313 5724 2 3902 2274 2685 1217 1628 3 5266 2274 2685 2581 2992 4 4236 2274 2685 1551 1962 5 4505 2274 2685 1820 2231 6 3868 2274 2685 1183 1594 7 2866 2274 2685 181 592 8 2635 2274 2685 0 361 9 2464 2274 2685 0 190 10 2354 2274 2685 0 80 11 1978 2274 2685 0 0 12 1848 2274 2685 0 0 13 1746 2274 2685 0 0 14 1627 2274 2685 0 0 15 1638 2274 2685 0 0 16 2794 2274 2685 109 520 17 2129 2274 2685 0 0 18 1985 2274 2685 0 0 19 2061 2274 2685 0 0 20 1970 2274 2685 0 0 21 1301 2274 2685 0 0 22 1338 2274 2685 0 0 23 1310 2274 2685 0 0 24 1448 2274 2685 0 0 25 1321 2274 2685 0 0

4.4 Excess Water Management

Excess groundwater over the mine life is displayed in Figure 5 and Table 10. Groundwater inflows

exceed low quality water demand for Year 1 to 10 and year 16 of mining. Excess water volumes

decrease from an initial volume of 5,500 kL/d (64 L/s) in year 1 to 520 kL/d (46 L/s) by year 16.

Managed Aquifer Recharge (MAR) into the hypersaline paleochannel aquifer has been evaluated. The

numerical model was used to simulate the gravity injection of excess groundwater to the deep

paleochannel aquifer (refer Appendix E, Section E7.1). Several injection borefield layouts were

simulated, adjusting both the individual injection rates and the bore spacing. However, the shallow

depth to water (with limited injection head) means many bores will be required to operate over a

very wide area, at low individual injection rates. MAR is unlikely to be cost-effective and no further

optimisation of MAR was considered.

Options for excess water management/reduction include:

Utilising spray canons over the waste dumps to facilitate evaporation.

Commence pumping from the dewatering bores early to spread the ‘peak’ over a longer

period of time.


5 IMPACT ASSESSMENT

The numerical groundwater flow model described in Appendix E was also used to predict the

drawdown impact of mining and the long term behaviour of the mined out voids. Details of the model

predictions are described in Appendix E.

5.1 Regional Drawdown Impact - End of Mining

Contours of predicted drawdown after 25 years of mining are shown in Figure 6. The predicted

drawdown is the difference between pre-mining water levels and the water levels predicted at the

end of mining (Year 25 of mine life). The following observations are made regarding the predicted

drawdown:

Maximum drawdown is predicted in Pit 1 (228 m).

Drawdown of 1 m is predicted a maximum distance of 8 km from the south eastern and

north western ends of the mining area (or 10 km from Pit 2 / the centre of the mining area).

This drawdown extends along the paleochannel south of the mine areas.

5.2 Mine Closure

Water levels in the mining areas are not predicted to recover due to the large evaporative area at

the base of each empty pit. The pits are predicted to develop into local sinks and pit lakes are

predicted to develop in the base of open pits and are discussed below:

Water levels in Pits 1, 3 and 4 remain close to dewatered levels of 300 mRL, 230 mRL and

360 mRL respectively or approximately 240 m, 170 m and 110 m below the pre-mining

ground surface respectively (or 230 m, 160 and 100 m below the pre-mining water table

respectively, refer Figure E14 and E15). These shallow pit void lakes may not persist

throughout the year as they respond to episodic rainfall / run off.

Water levels in Pit 2 are predicted to recover to 332 mRL or approximately 140 m below the

pre-mining ground level (~130 m below the pre-mining water table), 35 years after the

cessation of dewatering. The south eastern end of Pit 2 is located on the northern side of a

shallow tributary of the Lake Annean paleochannel. The Pit 2 void lake is predicted to be

approximately 20 m deep and is predicted to persist throughout the year. There may be

small fluctuations in pit lake elevation in response to episodic rainfall / run off.

Pit 4 is located within the shallow tributary of the Lake Annean paleochannel. As Pit 2 and

Pit 1 (located to the south of the tributary) are both deeper than Pit 4, groundwater flow is

towards Pits 1 and 2. As a result a pit lake is not predicted to develop in Pit 4.

The pits will function as long term groundwater sinks with sustained groundwater flow

towards the mined out voids and discharge through evaporation. This means there will be no

long term outflow of saline groundwater from the pits into the regional system.

Contours of predicted water level drawdown 100 years after the end of mining are shown in Figure 7.

The following observations are made regarding the predicted drawdown after mine closure:

Drawdown of 1 m is predicted to extend a maximum distance of 13 km to the north and

14 km to the south of the mine area (from the centre of Pit 2). Drawdown of 1 m is also

predicted to extend through the paleochannel aquifers a maximum distance of 15 km to the

south east of the centre of the mining area, and 18 km to the west.

In the mine areas, where pit lakes are expected to develop, water levels are between 100 m

to 230 m below pre-mining water levels.


6 CONCLUSIONS & RECOMMENDATIONS

6.1 Conclusions

Australian Vanadium Ltd (AVL) are undertaking a feasibility study of the Australian Vanadium Project

in the Murchison region of Western Australia. The project will involve open-cut mining to a depth of

approximately 240 mbgl.

Groundwater levels in the project area range between 470 mRL, to the northeast of the deposit, to

450 mRL, in the paleochannel area. Groundwater on the deposit occurs at 458 mRL which is between

10 and 15 mbgl. Dewatering will be required when mining below this depth.

The main regional aquifers in the project area comprise a deep paleochannel aquifer, to the south of

the orebody, and a laterally extensive shallow Tertiary aquifer.

The deep paleochannel aquifer comprises approximately 20 m of medium to coarse-grained sand,

gravel and cobbles, occurring at depths of approximately 100 mbgl, with a permeability of between

0.7 and ~3 m/d. Groundwater within this aquifer unit is hypersaline, with EC values of

180,000 µS/cm recorded.

In the paleochannel, overlying the basal aquifer is a 70 m thick unit of low permeability clay over

which lies the shallow Tertiary aquifer. Outside of the paleochannel, the shallow aquifer directly

overlies basement.

The shallow aquifer comprises calcrete and alluvial gravels and extends beyond the paleochannel,

forming a cover over the low-lying ground of the project area. The thickness of the unit is uniform

(~30 m) across the paleochannel area, but variable (0 to 80 m) across the orebody. Permeability

estimates for this unit range between 1 and 38 m/d and groundwater salinity (measured as EC)

generally ranges between ~4,000 and 20,000 µS/cm.

Although the ore and competent bedrock in the deposit area are generally of low permeability, local

aquifers comprise a saprock / transition zone and a fractured rock aquifer. The saprock / transition

zone aquifer occurs at depths ranging between 30 and 70 mbgl and is anticipated to have a variable

permeability due to changes in bedrock composition and oxidation characteristics. The fractured

basement tends to occur at depths between 100 and 180 mbgl, with derived permeability values

ranging between 0.2 and 3.3 m/d. Although the fracturing may be associated with the mapped faults

that cross-cut the orebody, it is anticipated that the higher yielding bores drilled to date intercept a

northwest-southeast trending fault (i.e. coincident with the strike of the deposit), possibly associated

with the footwall of the orebody.

A numerical model has been developed for the mine area and surrounding catchment and used to

simulate mine dewatering and associated impacts. The results of model predictions are summarised

below:

Dewatering requirements over the life of the mine, that includes four pits (Pits 1 to 4), peaks

during Year 1 of mining when dewatering rates of 8,000 kL/d are predicted, decreasing to

less than 1,500 kL/d by Year 25 of mining.

Site water demand, seasonally varying between 2,300 and 2,700 kL/d will result in an excess

of water of up to 5,700 kL/d. The model was also used to assess the potential for MAR into

the deep paleochannel aquifer to be used to manage excess water. The injection rates

required, the limited aquifer extent and the shallow depth to water predicted that injection


under gravity was not feasible. Groundwater levels in the lower aquifer were predicted to

increase to at or above ground level along the Lake Annean paleochannel and the tributaries

within a year of commencement of re-injection.

After 25 years of mining, drawdown of 1 m is predicted a maximum distance of 8 km from

the south eastern and north western ends of the mining area (or 10 km from Pit 2 / the

centre of the mining area). This drawdown extends along the paleochannel south of the

mine areas.

Water levels in the mining areas are not predicted to recover due to the large evaporative

area at the base of each empty pit. The pits are predicted to develop into local sinks and pit

lakes are predicted to develop in the base of open pits. Very shallow pit lakes (less than 1 m

in depth) are predicted to develop in Pits 1, 3 and 4 approximately 160 m, 230 m and 100 m

below the pre-mining water table, respectively. Water levels in Pit 2 are predicted to recover

to 332 mRL, or approximately 140 m below the pre-mining ground level, resulting in a pit

lake approximately 20 m deep. The south eastern end of Pit 2 is located on the northern

side of a shallow tributary of the Lake Annean paleochannel and higher inflows to this pit

are possible once mining in complete compared to the other pits.




As the pits are predicted to develop into groundwater sinks in the long term, predicted

drawdown is predicted to continue after the end of mining. Drawdown of 1 m is predicted to

extend a maximum distance of 13 km to north and 14 km to the south of the mine area

(from the centre of Pit 2). Drawdown of 1 m is also predicted to extend through the

paleochannel aquifers a maximum distance of 15 km to the south east of the centre of the

mining area, and 18 km to the west.

Although the groundwater is brackish in the shallow aquifer units over the orebody (with EC ranging

between 2,500 and 5,200 µS/cm), and potentially within the unfractured bedrock at depth (up to an

EC of 29,000 µS/cm), the groundwater is hypersaline (EC ~250,000 µS/cm ) within the higher

permeability fractures / faults at depths below ~100 mbgl. As groundwater inflow to the proposed

pit will be dominated by the higher permeability zones, the dewatering discharge will become

hypersaline as the pit depth progresses (or as soon as the main fault zone(s) are intercepted by

mining).

Based on the initially high dewatering estimates for the first year of mining and variability of

groundwater inflows to each pit, dewatering of the open pits would be best achieved through a

combination of:

Dewatering bores which can be used to dewater the higher permeability shallow aquifer

sediments associated with the large groundwater inflow volumes at the initiation of mining.

Dewatering bores should also target the permeable structure that is inferred to run along

the footwall of the pit. Bores should be located on the pit crest at either of the pit with

additional bores along strike and within the pit (if they can be accommodated from mining

logistics).


In-pit sump pumping to remove groundwater inflows from lower permeability units. The

mine plan should therefore allow for the presence of sumps within the pit and temporary

drains across the pit floor to direct groundwater to the sumps.

6.2 Recommendations

Hydrogeological field investigations should be extended over Pits 1, 2 and 4 to:

Confirm that the hydrogeological conditions remain consistent with those encountered at

Pit 1.

Install additional groundwater monitoring bores to extend the determination of baseline

conditions.

The dewatering assessment (modelling and data analysis) should be updated when the results from

field investigations over Pits 1, 2 and 4 are available.

As the project evolves, modelling should be undertaken to refine / optimize progression of dewatering

with a view to minimizing periods of water surplus. For example, this may involve opportunities to

commence dewatering sooner but at lower rates (i.e. to achieve advanced dewatering). Any

dewatering optimisation should wait until the results from field investigations over Pits 1, 2 and 4 are

available.


7 REFERENCES

Bell, J.G., Kilgour, P.L., English, P.M., Woodgate, M.F., Lewis, S.J. and Wischusen, J.D.H. (compilers),

2012. WASANT Paleovalley Map – Distribution of Paleovalleys in Arid and Semi-arid WA-SA-NT (First

Edition), scale: 1:4 500 000, Geoscience Australia Thematic Map (Geocat № 73980) – hard-copy and

digital data publication: http://www.ga.gov.au/cedda/maps/96.

Cashman, P. and M Preene, 2013. Groundwater Lowering in Construction: A Practical Guide to

Dewatering.

Davis, A., S. Macaulay, T. Munday, C. Sorensen, J. Shudra and T. Ibrahimi, 2016, Uncovering the

groundwater resource potential of Murchison Region in Western Australia through targeted

application of airborne electromagnetics: 25th International Geophysical Conference and Exhibition,

ASEG-PESA-AIG, 459–464.

Marinelli F, Niccoli, WL, 2000, Simple Analytical Equations for estimating Groundwater Inflow to a

Mine Pit, Groundwater, Vol 38 no.2, pp311 – 314.

FIGURES

< No Content >

LOCATION MAP

FIGURE 1PROJECT AREA

Location: F:\183\4.GIS\Workspaces\Figures\Report Figures

KEY

NOTES & DATA SOURCES:AUTHOR: LDS REPORT NO: 048

DRAWN: LDS REVISION: a

DATE: 02/12/19 JOB NO: 183

PERTH

ProjectKALGOORLIE

PROJECT

Proposed Pit Outline

Tenement Boundary

Paleochannel Thalweg

PERTH

Project

KALGOORLIE

Project

PERTH

ALBANY

KALGOORLIE

NEWMAN

DERBY

LOCATION MAP

MONITORING AND PRODUCTION BORE LOCATIONS

Location: F:\183\4.GIS\Workspaces\Figures\LDS Figures

LEGEND

NOTES & DATA SOURCES:AUTHOR: LDS REPORT NO: 048

DRAWN: LDS REVISION: A

DATE: 08/03/2021 JOB NO: 183

Production Bores

Palaeochannel Monitoring Bores

Orebody Monitoring Bores

FIGURE 2

TEM Transects

Paleochannel Thalweg0 2

kilometres

Scale 1:65,000Paleochannel Boundary

Pit 1

Pit 2

Pit 3

Pit 4

LOCATION MAP

FIGURE 3

HYDROGEOLOGY

Location: F:\183\4.GIS\Workspaces\Figures\LDS Figures

KEY

NOTES & DATA SOURCES:AUTHOR: LDS REPORT NO:

DRAWN: LDS REVISION: a

DATE: 09/11/2020 JOB NO: 183

PERTH

Project

KALGOORLIE

PROJECT

Geotechnical Bores

DWER Bores

Drainage

Tenements

Pit

WL Contours (10m)

Palaeochannel

Inferred Paleochannel Access

Date: 11/11/19 Description:

F:\183\2.TECH\[183_AQ2CHEM_revC w legend.xlsm]EXPANDED DUROV (1) Client: AVL

Figure 4Expanded Durov Diagram

Project: Gabanintha

Project No: 183

Orebody RC & DD Holes

Orebody Bores

Paleochannel Shallow

Paleochannel Deep

Na+ 25%Mg2+ 25%

Mg2+ 50%

Ca2+ 25%

Na+ 25%

Ca2+ 25%

Na+ 25%

Ca2+ 25%

Mg2+ 25%

Ca2+ 50%

HCO3- 50%

HC

O3

-2

5%

SO

42

-2

5%

HC

O3

-2

5%

Cl-

25

%

1.

8.

2.

9.7.

6.5.4.

3.

Na+ 50%

SO

42

-2

5%

Cl-

25

%

HC

O3

-2

5%

Cl-

25

%

SO

42

-5

0%

Cl-

50

%

0 20000 40000 60000 80000 100000 120000 140000 160000 180000

TDS (mg/L)

1. HCO3- and Ca2+ dominant (frequently indicates recharging waters)

2. HCO3- dominant and Mg2+ dominant or cations indiscriminant

3. HCO3- and Na+ dominant (ion exchanged waters)

4. SO42- dominant or anions indiscriminant and Ca2+ dominant (recharge/mixed water)

5. No dominant anion or cation (dissolution/mixing)

6. SO42- dominant or anions indiscriminant and Na+ dominant (mixing influences)

7. Cl- and Ca2+ dominant (cement pollution or reverse ion exchange of NaCl waters)

8. Cl- dominant and no dominant cation (reverse ion exchange of NaCl waters)

9. Cl- and Na+ dominant (end point water)

WATER TYPE SUB-FIELDS

Dewatering Volumes and Disposal Requirements FIGURE 5F:\183\3.C&R\048 Figs & App\Appendix E_Modelling\[Figure E10 - Dewatering Volumes.xlsx]Figure 5

0

1000

2000

3000

4000

5000

6000

7000

8000

9000

0 5 10 15 20 25

Rat

e (

kL/d

ay)

Years

Dewatering Rate (kL/day) Upper Disposal Limit (kL/d) Lower Disposal Limit (kL/d)

APPENDIX A

TEM SURVEY RESULTS

Datum: GDA 94Grid: MGA Zone 50

Southern Geoscience Consultants Pty LtdACN 067 552 461

Drawn: G.Maude

Scale: 1:15,000

Date: Mar-2019

Figure:

GABANINTHA PROJECTCoincident Loop EM SurveyTEM PROFILESCDI SECTIONLine 1000

GABANINTHA PROJECTCoincident Loop EM Survey

TEM PROFILESCDI SECTION

Line 1000

-100 0 100 200 300 400 500

Scale 1:15000

WINDOW TIMES (ms): Centre From the end of the turn off (160.3 ms)1 : 0.09952 : 0.12453 : 0.15404 : 0.19105 : 0.23756 : 0.29507 : 0.36608 : 0.45459 : 0.564510 : 0.700511 : 0.869512 : 1.08013 : 1.34114 : 1.66415 : 2.06616 : 2.56517 : 3.184

18 : 3.95319 : 4.90820 : 6.09321 : 7.56422 : 9.39023 : 11.6624 : 14.4725 : 17.9726 : 22.3127 : 27.6928 : 34.3829 : 42.6830 : 52.9931 : 65.7932 : 81.6733 : 101.434 : 125.9

SURVEY PARAMETERS

Configuration : Coincident LoopStation Spacing : 100 m

RECEIVER

Receiver : SMARTem24Frequency : 1.5625Component : ZRx Coil : Loop WireRx Area : 10000 turn-m

TRANSMITTER

Transmitter : Zonge NT-20Tx Loop Side : 100 mTx Current : 8.4-8.6 ATurn Off : 0.3 ms

Z Component Log Scale - Channels 1 to 34

EM R

espo

nse

(uV/

A)

-1-1

0

11

10

100

1000

10000

100000

Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200

0.09950.12450.1540.1910.23750.2950.3660.45450.56450.70050.86951.081.34051.6642.0662.56453.1843.9534.90756.09257.56359.390511.65814.47317.96822.307

27.6935

34.380542.68352.9965.785581.671101.393125.8765

Channels 1-34

Z Component Linear Scale - Channels 25 to 34

EM R

espo

nse

(uV/

A)

-0-0

6

12

18

24

30

Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200

17.968

22.30727.693534.380542.68352.9965.785581.671101.393125.8765

Channels 25-34

200200

300

400

500

600

700

800

900mS/mEMAX CDI Section

Pseu

dode

pth

-250-250

-200

-150

-100

-50

0

Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200



Drawn: G.Maude

Scale: 1:15,000

Date: Mar-2019

Figure:




Line 2000

-100 0 100 200 300 400 500

Scale 1:15000


18 : 3.95319 : 4.90820 : 6.09321 : 7.56422 : 9.39023 : 11.6624 : 14.4725 : 17.9726 : 22.3127 : 27.6928 : 34.3829 : 42.6830 : 52.9931 : 65.7932 : 81.6733 : 101.434 : 125.9

SURVEY PARAMETERS


RECEIVER


TRANSMITTER



EM R

espo

nse

(uV/

A)

-1-1

0

11

10

100

1000

10000

100000

Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400

0.09950.12450.1540.1910.23750.2950.3660.45450.56450.70050.86951.081.34051.6642.0662.56453.1843.9534.90756.09257.56359.390511.65814.47317.96822.30727.693534.380542.68352.9965.785581.671101.393125.8765

Channels 1-34


EM R

espo

nse

(uV/

A)

-0-0

6

12

18

24

30

Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400

17.96822.30727.693534.380542.68352.9965.785581.671101.393125.8765

Channels 25-34

00

200

400

600

800


Pseu

dode

pth

-250-250

-200

-150

-100

-50

0

Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400



Drawn: G.Maude

Scale: 1:15,000

Date: Mar-2019

Figure:




Line 3000

-100 0 100 200 300 400 500

Scale 1:15000


18 : 3.95319 : 4.90820 : 6.09321 : 7.56422 : 9.39023 : 11.6624 : 14.4725 : 17.9726 : 22.3127 : 27.6928 : 34.3829 : 42.6830 : 52.9931 : 65.7932 : 81.6733 : 101.434 : 125.9

SURVEY PARAMETERS


RECEIVER


TRANSMITTER



EM R

espo

nse

(uV/

A)

-1-1

0

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100

1000

10000

100000

Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600

0.09950.12450.1540.1910.23750.2950.3660.45450.56450.70050.86951.081.34051.6642.0662.56453.1843.9534.90756.0925

7.5635

9.3905

11.658

14.473

17.96822.30727.693534.380542.68352.9965.785581.671101.393125.8765

Channels 1-34


EM R

espo

nse

(uV/

A)

-0-0

6

12

18

24

30

Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600

17.96822.30727.693534.380542.68352.9965.785581.671101.393125.8765

Channels 25-34

100100

200

300

400

500

600

700


Pseu

dode

pth

-250-250

-200

-150

-100

-50

0

Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200 3400 3600



Drawn: G.Maude

Scale: 1:15,000

Date: Mar-2019

Figure:




Line 4000

-100 0 100 200 300 400 500

Scale 1:15000


18 : 3.95319 : 4.90820 : 6.09321 : 7.56422 : 9.39023 : 11.6624 : 14.4725 : 17.9726 : 22.3127 : 27.6928 : 34.3829 : 42.6830 : 52.9931 : 65.7932 : 81.6733 : 101.434 : 125.9

SURVEY PARAMETERS


RECEIVER


TRANSMITTER



EM R

espo

nse

(uV/

A)

-1-1

0

11

10

100

1000

10000

100000

Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200

0.09950.12450.1540.1910.23750.2950.3660.45450.56450.70050.86951.081.34051.6642.0662.56453.1843.9534.90756.09257.5635

9.3905

11.658

14.473

17.968

22.30727.693534.380542.68352.9965.785581.671101.393125.8765

Channels 1-34


EM R

espo

nse

(uV/

A)

-0-0

6

12

18

24

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Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200

17.96822.30727.693534.380542.68352.9965.785581.671101.393125.8765

Channels 25-34

00

200

400

600

800

1000


Pseu

dode

pth

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200 400 600 800 1000 1200 1400 1600 1800 2000 2200 2400 2600 2800 3000 3200



Drawn: G.Maude

Scale: 1:15,000

Date: Mar-2019

Figure:




Line 5000

-100 0 100 200 300 400 500

Scale 1:15000

WINDOW TIMES (ms): Centre From the end of the turn off (160.3 ms)1 : 0.09952 : 0.12453 : 0.15404 : 0.19105 : 0.23756 : 0.29507 : 0.36608 : 0.45459 : 0.564510 : 0.700511 : 0.869512 : 1.08013 : 1.34114 : 1.66415 : 2.06616 : 2.56517 : 3.18418 : 3.953

19 : 4.90820 : 6.09321 : 7.56422 : 9.39023 : 11.6624 : 14.4725 : 17.9726 : 22.3127 : 27.6928 : 34.3829 : 42.6830 : 52.9931 : 65.7932 : 81.6733 : 101.434 : 125.935 : 156.336 : 194.0

SURVEY PARAMETERS


RECEIVER


TRANSMITTER



EM R

espo

nse

(uV/

A)-1-1

0

11

10

100

1000

10000

100000

Station (metres)

0 200 400 600 800 1000 1200 1400 1600 1800 2000

0.09950.12450.1540.1910.23750.2950.3660.45450.56450.70050.86951.081.34051.6642.0662.56453.1843.9534.90756.09257.56359.390511.65814.473

17.968

22.307

27.6935

34.3805

42.68352.9965.785581.671101.393125.8765

Channels 1-36


EM R

espo

nse

(uV/

A)

-0-0

8

16

24

32

40

Station (metres)

0 200 400 600 800 1000 1200 1400 1600 1800 2000

17.968

22.307

27.693534.380542.68352.9965.785581.671101.393125.8765

Channels 25-35

200200

400

600

800

1000


Pseu

dode

pth

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0 200 400 600 800 1000 1200 1400 1600 1800 2000



Drawn: G.Maude

Scale: 1:15,000

Date: Mar-2019

Figure:




Line 6000

-100 0 100 200 300 400 500

Scale 1:15000


18 : 3.95319 : 4.90820 : 6.09321 : 7.56422 : 9.39023 : 11.6624 : 14.4725 : 17.9726 : 22.3127 : 27.6928 : 34.3829 : 42.6830 : 52.9931 : 65.7932 : 81.6733 : 101.434 : 125.9

SURVEY PARAMETERS


RECEIVER


TRANSMITTER



EM R

espo

nse

(uV/

A)

-1-1

0

11

10

100

1000

10000

100000

Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200

0.09950.12450.1540.1910.23750.2950.3660.45450.56450.70050.86951.081.34051.6642.0662.56453.1843.9534.90756.09257.56359.390511.65814.473

17.968

22.307

27.6935

34.380542.68352.9965.785581.671101.393125.8765

Channels 1-34


EM R

espo

nse

(uV/

A)

-0-0

8

16

24

32

40

Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200

17.968

22.307

27.693534.380542.68352.9965.785581.671101.393125.8765

Channels 25-34

200200

300

400

500

600

700

800

900


Pseu

dode

pth

-250-250

-200

-150

-100

-50

0

Station (metres)

200 400 600 800 1000 1200 1400 1600 1800 2000 2200

APPENDIX B

BORELOGS

Project:Client:

Logged By:

COMPOSITE WELL LOG

Drilled:

Commenced:S

trat Well Completion

Field NotesDepth GraphicLog(mbgl)

Lithological DescriptionNotesDiagram

Easting:

Northing:

Bore No:

Static Water Level:

Elevation:

Remarks:

Area:

Projection:Australia

Method:

Completed:

WA 6005

Aq

uif

er

+61 8 93215594

West Perth

85 Havelock St

Bit Record:

File Ref: Well No:

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Australian Vanadium Gabanintha

9/04/2019

27/04/2019

Ausdrill North West

Liam Storey

14.14 mbtoc

468 mRL

666070

7011649

0.75m Stick up

Palaeochannel

GDA94 zone 50J

19AVWM01

DR 0-134m

241mm

F:\183\2.TECH\LogPlot 19AVWM01

Airlift yield = <1 L/s, EC= 1000 uS/cm

Airlift yield = 4 L/s, EC =30000 uS/cm, pH = 7.3

Airlift yield = 6.5 L/s, EC= 182000 uS/cm

Completion Airlift = 0.1L/s

Laterite: Sand - Gravel; angular to sub angular.Trace of silt. Purplish-brown; trace of grey.Ferricrete with the Quartz.

Duricrust: Sand - Gravel; angular to sub angular.Increased silt content. Purplish-brown with blacktraces. Magnetite present; medium - coarsegrained (10%).

Colluvium: Gravel; angular to sub angular. Red-brown. Quartz; medium grained; angular. Minorsilt. Silcrete; medium - large grained. Weatheredclasts; brittle.

Alluvium: Gravel; angular - sub angular. Red -brown - cream. Fined grained quartz. Calcrete 1-10mm grain size, angular (2%).

Sand and Clay: Green - grey, sub angular. Minorsand and gravel. Indurated clay.

Clay: Trace of sand. Brown-red.

Clay: Puggy. Mottled green-light brown.

Clay: Trace of very fine quartz sand. Pale Grey.

Clay: Puggy. Mottled green.

Calcrete: Weathered calcareous clay. Grey-white. Clasts up to 3mm.

Clay: Puggy. Light brown-grey.

Calcrete: Weathered calcareous clay. Grey-white. Clasts up to 3mm.

Clay: Sandy.

Gravel and Sand: Angular to sub angular Quartz(1-4mm). Sub angular to sub rounded Gravel(2-15mm).

Sandy Clay: Yellow/grey. Fine - medium grainedsand. Minor calcrete. Sand content increase at112-114m.

Clayey Sand: 10% clay 90% sand.

Sand and Clay: Coarse Qtz sand 50% andpuggy clay 50%.

Sand and Clay: 10% clay 90% sand.Predominantly quartz upto 15mm. WeatheredMafic clasts (basalt) 20mm. Magnetite 1mm 2%.

Clay and Sand: Puggy clay 60%. Sand, Qtz,angular. Clay content increasing at 128m.

Clayey Sand: 10% clay 90% sand (coarsegrained). Orange/brown. Qtz, ang - sub ang 1-5mm.

Bedrock: Ultra mafic (basalt) 70% sand 30%.Basalt: fine grained, dark grey/green,Plagioclase 1mm, magnetite 1mm, trace ofsulphides (pyrite?).

0-98m Blank 50mmPVC Class 12

0-125m 203mm DRSteel Casing. Casingsnapped whilebeing retrieved

1.2-3.6mm GravelPack

93-96m BentoniteSeal

98-134m 1mmSlotted 50mm PVCClass 12

Project:Client:

Logged By:

COMPOSITE WELL LOG

Drilled:

Commenced:S




Easting:

Northing:

Bore No:

Static Water Level:

Elevation:

Remarks:

Area:


Completed:

WA 6005

Aq

uif

er

+61 8 93215594

West Perth

85 Havelock St

Method:

Bit Record:

File Ref: Well No:

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28/04/2019

10/05/2019

Ausdrill North West

Liam Storey

11.65 mbtoc

463 mRL

661573

7012645

0.86m Stick up

Palaeochannel

GDA94 zone 50J

19AVWM02d

DR 0-138m

241mm

F:\183\2.TECH\LogPlot 19AVWM02d

FWS Airlift yield = <1L/s

Airlift yield = 5 L/s, EC =8000 uS/cm, pH = 7.97

Increased fluid return(~5-6 L/s) @ 25m

Airlift yield = 1.6 L/s, EC= 164000 uS/cm, pH =6.7

Airlift yield = 7-10 L/s

Airlift yield = 7 L/s, EC =181000 uS/cm, pH =7.22

Airlift yield = >10 L/s

Duricrust: Sand - Gravel; angular to sub angular.Minor silt content. Trace of Magnetite. Trace ofCalcrete at 8m.

Alluvium: Gravel; angular - sub angular. Brown -purple - red. Fined grained quartz. Calcrete 1-30mm grain size, angular (2%), increases at22m.

Gravel and Clay: Hardened clay, green/grey.Gravel, angular, up to 5mm. Calcrete clasts upto 3mm. Injurated clay. Magnetite <1mm.

Alluvium: Gravel, ang - sub ang 3mm,purple/brown. Calcrete clasts up to 15mm (40-50%). Minor hardened clay (5%).

Gravel and Clay: Hardened clay, green/grey.Gravel, ang, up to 5mm. Calcrete clasts up to8mm. Magnetite <1mm. Minor ultramafic claysup to 10mm. Increased silt. Qtz 1mm sub ang -sub rounded.

Clay: Brown/red, hard. Trace of sand and gravel.

Clay: Puggy clay. Trace of sand. Mottledgreen/light brown. Turns purple at 32-34m.Trace of magnetite.

Clay: Puggy clay. Grey/green/light brown. Minorfine grained qtz.

Clay: Puggy clay. Red Brown. Minor fine sand.

Clay: Puggy clay. Mottled green/grey. Increasedsand and gravel at 80m.

Clay: Gravelly puggy clay (60%). Gravel, clastsup to 20mm, ang - sub ang, minor magnetite thatincreases at 94m (40%).

Gravel and Clay: Clay 50%. Gravel, ang - subang, upto 3mm, minor magnetite, 50%.

Clay: Puggy clay 70%. Gravel, ang to sub angorange red, 30%.

Gravel: Quartz 2-4mm clean gravel, ang to subang.

Gravel: Black clays and black weathered shale.

Gravel: Rock clasts 50mm quartz cobbles. 10%clay 90% 2-7mm gravel (Q, BIF, maficfragments).

Basement: Very dark grey, fine grained basalt.





Project:Client:

Logged By:

COMPOSITE WELL LOG

Drilled:

Commenced:S




Easting:

Northing:

Bore No:

Static Water Level:

Elevation:

Remarks:

Area:


Completed:

WA 6005

Aq

uif

er

+61 8 93215594

West Perth

85 Havelock St

Method:

Bit Record:

File Ref: Well No:

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10/04/2019

14/05/2019

Ausdrill North West

Liam Storey

7.76 mbtoc

463 mRL

661591

7012641

0.88m Stick up

Palaeochannel

GDA94 zone 50J

19AVWM02s

DR 0-28m

241mm

F:\183\2.TECH\LogPlot 19AVWM02s

FWS Airlift yield = <1L/s

Increased water return

Airlift yield = 6 L/s, EC =7600 uS/cm

Decreased water return

Completed airlift = 1.5L/s, 11000 uS/cm

Duricrust: Sand - Gravel; angular to sub angular.Minor silt content. Trace of Magnetite. Trace ofCalcrete at 8m.

Alluvium: Gravel; angular - sub angular. Brown -purple - red. Fined grained quartz. Calcrete 1-30mm grain size, angular (2%), increases at22m.

Gravel and Clay: Hardened clay, green/grey.Gravel, angular, up to 5mm. Calcrete clasts upto 3mm. Injurated clay. Magnetite <1mm.

Alluvium: Gravel, ang - sub ang 3mm,purple/brown. Calcrete clasts up to 15mm (40-50%). Minor hardened clay (5%).

Gravel and Clay: Hardened clay, green/grey.Gravel, ang, up to 5mm. Calcrete clasts up to8mm. Magnetite <1mm. Minor ultramafic claysup to 10mm. Increased silt. Qtz 1mm sub ang -sub rounded.


4-7m Bentonite Seal

3.6 - 6.4mm GravelPack

10-28m 3mm Slotted50mm PVC Class18

Project:Client:

Logged By:

COMPOSITE WELL LOG

Drilled:

Commenced:S




Easting:

Northing:

Bore No:

Static Water Level:

Elevation:

Remarks:

Area:


Completed:

WA 6005

Aq

uif

er

+61 8 93215594

West Perth

85 Havelock St

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14/04/2019

16/05/2019

Ausdrill North West

KO

4 mbtoc

458 mRL

654653

7014407

0.83m Stick up

Palaeochannel

GDA94 zone 50J

19AVWM03

DR 0-28m

241mm


FWS


Airlift yield = 10 L/s, EC= 8300 uS/cm

Airlift = 7 L/s

No water return

Completed airlift = 8860uS/cm

Alluvium: Gravel; angular to sub angular. Brown.Minor calcrete (2mm) 5%. Minor clay.

Alluvium: Gravel; angular to sub angular. Browncream with minor black. Calcrete clasts up to40mm, increasing content at 6m. Minorultramafic clasts upto 10mm. Becomes purplebrown at 12m, increase magnetite.

Gravel: Rock clasts and gravel up to 40mm, subrounded to angluar. Calcrete clasts upto 40mm.Minor magnetite. Minor Quartz; angular to subangular. High yielding (10 L/s). Increased siltcontent at 22m.

Gravel and Clay: Gravel 70%; angular, minorcalcrete. Clay 30%.

Clay: Gravelly clay with hardened clay clasts upto 50mm. Brown.


2-4m Bentonite Seal

3.6 - 6.4 mm GravelPack

4-28m 3mm Slotted50mm PVC Class 18

Project:Client:

Logged By:

COMPOSITE WELL LOG

Drilled:

Commenced:S




Easting:

Northing:

Bore No:

Static Water Level:

Elevation:

Remarks:

Area:


Completed:

WA 6005

Aq

uif

er

+61 8 93215594

West Perth

85 Havelock St

Method:

Bit Record:

File Ref: Well No:

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16/05/2019

18/05/2019

Ausdrill North West

KO

8.43 mbtoc

464 mRL

663545

7011754

0.77m Stick up

Palaeochannel

GDA94 zone 50J

19AVWM04

DR 0-28m

241mm


Airlift = 0.5 L/s

Airlift = 5 L/s

Airlift = 10 L/s, EC =13370 uS/cm

Airlift = 10-12 L/s, EC =13650 uS/cm

Completion Airlift = 2L/sEC = 17630 uS/cmpH = 7.62

Soil: Surficial soil with rock fragments. Redbrown, angluar caprock and silty soils.

Gravel: Sandy. Tan/khaki clay, silt and rockfragments 10-40mm.

Calcrete: Ivory calcrete with brown coarse sandand gravel 1-8mm. CaCO3 80%.

Gravel and Sand: Brown sandy gravel and clay(30%). Rock fragments 10-25mm.

Clay: Red brown clay with sandy gravel. Clay80%.

2-4m Bentonite Seal

0-22m Blank 50mmND PVC Class 18


22-28m 3mm Slotted50mm ND PVCClass 18

Project:Client:

Logged By:

COMPOSITE WELL LOG

Drilled:

Commenced:S




Easting:

Northing:

Bore No:

Static Water Level:

Elevation:

Remarks:

Area:


Completed:

WA 6005

Aq

uif

er

+61 8 93215594

West Perth

85 Havelock St

Method:

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File Ref: Well No:

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23/05/2019

29/05/2019

Ausdrill North West

KO

13.96 mbtoc

469.50 mRL

663778

7015448

0.84m Stick up

Orebody

GDA94 zone 50J

19AVWM104

DR 0-60m

DDH 60-175m

241mm(0-60m)/191mm(60-175m)


FWS

Airlft yield = <1 L/s


Airlfit yield = <1 L/s

Airlift yield = <1 L/s

Airlift yield = 1 L/s





Airlift yield = 10 L/s, EC> 240000 uS/cm

Airlift yield = 6 L/s, EC >240000 uS/cm


Airlift yield = 5.0 L/s



Duricrust: Red - brown, silty. Gravel; anguar tosub angular, clasts upto 20mm. Trace ofmagnetite. Trace of Calcrete.

Calcrete: Weathered calcrete, purple - cream,clasts upto 20mm. Gravel; angular to subangular. High silt content. Minor clay.

Saprock: Weathered igneous rock sub roundedto angular. Clasts of ultra mafic upto 20mm. 50%clay; purple brown.

Saprock: Gravelly. Grey - brown, puggy clay(weathered bedrock). Minor gravel.

Saprock: Clayey (weathered bedrock). Red -brown - purple. Gravel; angular to sub angular.Clay 30%, decreasing with depth. Gravelbecoming fine grained at 38m.

Mafic: Weathered igneous rock (dolerite?) withminor gravels. 20% clay. Highly magnetic.

Mafic: Fresh igneous rock, highly magnetic,minor gravels. 30% clay. Quartz up to 2mm.

Mafic: Purple weathered igneous rock. Highlymagnetic, fine grained.

Ore: Dark green - black- metallic. Highlymagnetic. Minor gravel. Ore content increasingat 92m. Fine grained with clasts up to 15mm.

Ore: Green fractured mafic igneous rock.Plagioclase & Pyroxene present. Highlymagnetic. Minor Sulphides.

Basement: Competent rock dark green - purple,fractured igneous rock. Minor ore/magnetite.Large quartz; angular to sub angluar up to20mm, weathered. High sulphide content.

2-4m Bentonite Seal






Project:Client:

Logged By:

COMPOSITE WELL LOG

Drilled:

Commenced:S




Easting:

Northing:

Bore No:

Static Water Level:

Elevation:

Remarks:

Area:


Completed:

WA 6005

Aq

uif

er

+61 8 93215594

West Perth

85 Havelock St

Method:

Bit Record:

File Ref: Well No:

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29/05/2019

2/06/2019

Ausdrill North West

KO

12.49 mbtoc

469 mRL

663421

7016066

0.82m Stick up

Orebody

GDA94 zone 50J

19AVWM105

DR 0-84m

DDH 84-178m

241mm(0-84m)/191mm(84-178)


FWS















Duricrust: Red brown, silty sand and gravel.Sand; fine grained. Gravek; ang to sub angclasts up to 30mm. High magnetite content.Large clasts of ultra mafics.

Gravel: Red - brown, silty. Gravel; ang to subang. 20% clay.

Clay: With minor gravel (20%).

Gravel and Clay: 50% gravel; red brown, ang tosub ang. 50% clay.

Saprolite: Red - brown, silty. Puggy clay withgravel. High magnetite content.

Saprock: Weathered igneous rock with minorgravels. Clasts up to 50mm; ang to sub ang.Clay 30%.

Saprock: Red black medium - coarse grained;sub rounded - sub ang. 50% ore 50% gravel.

Saprock: Weathered ignenous rock with minorgravels. Clasts upto 10mm. High magnetitecontent. 40% clay - becoming hard andgreen/yellow @ 70m.

Saprock: Yellow - green- grey stiff mottled clay(70%). Weathered igneous rock/gravel ang - subang. High magnetite content.

Ultra Mafic: Weathered igneous rock (basalt?)purple - dark green. Minor clay increasing @96m. High magentite content. Minor Quartz -ang to sub ang, weathered.

Ore: Black metallic magnetite; ang to sub angfine grained with large clasts upto 30mm (80%).Weathered igneous rock (20%).Limitted Quartzand high sulphide content (pyrite).

Basement: Grey grren weathered ignenous rock.Quartz; ang to sub ang. Minor gravel. Minor clay- stiff. Minor fine grained magnetite.

2-4m Bentonite Seal






Project:Client:

Logged By:

COMPOSITE WELL LOG

Drilled:

Commenced:S




Easting:

Northing:

Bore No:

Static Water Level:

Elevation:

Remarks:

Area:


Completed:

WA 6005

Aq

uif

er

+61 8 93215594

West Perth

85 Havelock St

Method:

Bit Record:

File Ref: Well No:

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80

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19/05/2019

23/05/2019

Ausdrill North West

KO

12.30 mbtoc

470.00 mRL

663916

7015608

0.8m Stick up

Orebody

GDA94 zone 50J

19AVWM108

DR 0-34m

DDH 34-100m

241mm(0-34m)/191mm(34-100m)


FWS

Seepage only

Airlfit yield = 2 L/sEC = 12520 uS/cmpH = 7.72

Airlfit yield = 3 L/s

Completed Airlift = 0.6 -0.7 L/sEC = 28800 uS/cm

Duricrust: Red brown silty coarse sand andangular to sub angular gravel rock fragments 2-10 mm

Calcrete: Pinkish brown weathered calcrete andsilty gravels comprised of rock fragments 4-8mmdiameter.

Calcrete: Purplish ivory calcrete with weatheredrock fragments and pebbles.

Ore: Purple brown highly weathered ore bodybasalt, ~50% remnant clay.

Ore: Purple weathered ore body basalt, clay~30%, highly fractured.

Ore: Green grey highly weathered ore body hostrock, friable cuttings in fracture zone.

Ore: Whitish grey fractured and weathered hostcountry rock, highly weathered

Mafic: Grey green competent host country rock,minor fracturing





Project:Client:

Logged By:

COMPOSITE WELL LOG

Drilled:

Commenced:S




Easting:

Northing:

Bore No:

Static Water Level:

Elevation:

Remarks:

Area:


Completed:

WA 6005

Aq

uif

er

+61 8 93215594

West Perth

85 Havelock St

Method:

Bit Record:

File Ref: Well No:

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3/06/2019

9/06/2019

Ausdrill North West

KO

8.32 mbtoc

468 mRL

664733

7014236

0.8m Stick up

Orebody

GDA94 zone 50J

19AVWM112

DR 0-88m

DDH 88-151m

241mm(0-88m)/191(88-151m)


FWS

Airlft yield = <1 L/s, EC= 4300 uS/cm

Airlfit yield = 9 L/s, EC =3420 uS/cm

Airlfit yield = 18 L/s, EC= 2950 uS/cm


No fluid return










Duricrust: Red brown silty angular to sub-angular gravels, with minor calcrete clasts up to10mm.

Calcrete: Red brown and cream weathered andfresh calcrete (50%),silty weathered caprockclasts up to 20mm.

Clay: Brownish cream silty clay with finecalcareous sand.

Calcrete: Pale white fine- grained chalky sandwith clasts up to 40mm

Saprock: Red brown and cream medium tocoarse angular to subangular silty gravel withlarge clasts of weathered caprock.

Saprock: Red brown to Black angular to sub-angular fine- coarse grained gravels with minormagnetite. Large clasts of weathered caprock.

Saprock: Dark green to purple weatheredigneous; clastsup to 10cm, subrounded toangular with 50% angular to sub- angulargravels and minor magnetite.

Saprock: GRAVELLY CLAY Grey brown clay50%, angular to subangular gravel with largecaprock clasts and magnetite

Mudstone: Red to dark brown medium to coarsegrained angular to subangular gravel; largeclasts of mudstone, silty with high magnetite %,minor angular quartz at 55m.

Ultra Mafic: Grey green weathered basalticigneous rock with calcareous band 70- 72m.Friable above with weathering degreedecreasing with depth.

Ore: Dark grey green competent crystalline orebody, mafic basaltic with iron pyrite at base 136-140m.

Ultra Mafic: Pale grey basalt with quartz richfracture zone 142- 151m.

2-4m Bentonite Seal





3.6 - 6.4mm GravelPack


Gravel pack insidecasing duringairlifting- blockedbore

Project:Client:

Logged By:

COMPOSITE WELL LOG

Drilled:

Commenced:S




Easting:

Northing:

Bore No:

Static Water Level:

Elevation:

Remarks:

Area:


Completed:

WA 6005

Aq

uif

er

+61 8 93215594

West Perth

85 Havelock St

Method:

Bit Record:

File Ref: Well No:

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10/06/2019

15/06/2019

Ausdrill North West

KO

11.80 mbtoc

472 mRL

662879

7017174

0.8m Stick up

Orebody

GDA94 zone 50J

19AVWM113

DR 0-52m

DDH 52-142m

241mm(0-52m)/191(52-142m)


Seepage only

Seepage only

FWS

Airlfit yield = 2-3 L/s







Duricrust: Red brown angular clasts, gravel andsand up to 12mm.

Gravel: Red brown gravel and sand, minor clay.10% calcrete. Coarse sand; angular.

Gravel: Pink purple orange gravels, sub roundedto angular. Minor clay and magnetite (roundedpebbles and gravels up to 3mm). Calcretenodules up to 2mm.

Gravel: Khaki grey/tan weathered basalt gravels,angular magnetite coarse sand, clay 40-50%,silty.

Basalt: Grey green, angular to sub angularbasalt. Becoming fine grained at 78m. High siltcontent at 56-68m. Magntite/ore; sub angular.

2-4m Bentonite Seal





Project:Client:

Logged By:

COMPOSITE WELL LOG

Drilled:

Commenced:S




Easting:

Northing:

Bore No:

Static Water Level:

Elevation:

Remarks:

Area:


Completed:

WA 6005

Aq

uif

er

+61 8 93215594

West Perth

85 Havelock St

Method:

Bit Record:

File Ref: Well No:

0

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19/06/2019

27/06/2019

Ausdrill North West

LS

10.32 mbtoc

467 mRL

663427

7015416

0.8m Stick up

Orebody

GDA94 zone 50J

19AVWM114

DR 0-106m

DDH 106-148m

241mm(0-106m)/191(106-148m)


FWS



Airlfit yield = 3-4 L/s, EC= 3940 uS/cm

Airlift yield = 8-10 L/s,EC = 3780 uS/cm

Airlift yield = 8-10 L/s,EC = 3690 uS/cm


Airlift yield = 7-9 L/s, EC= 5210 uS/cm








Airlift yield = 5-6 L/s, EC= 197000 uS/cm




Duricrust: Red brown gravel and sand; angular -sub angular, clasts upto 12mm.

Gravel: Red brown gravel (1-4mm) and sand,minor clay. Highly magnetic; angular.

Gravel: Red brown large gravel clasts upto30mm; angular - sub rounded. Highly magnetic.Minor clay at 28m.

Gravel and Clay: Red brown gravel (1-4mm);angular. Clay 60%.

Calcrete: Weathered, White red clay, mix of softand stiff. Minor gravel and magnetite. Large hardcalcrete clasts upto 60mm.

Calcrete: Red white soft weathered calcrete(60%) with large calcrete clasts upto 50mm;angular - sub angular. Gravel; medium - coarsegrained 1-5mm gravel ang-sub angular.

Gravel and Clay: Soft clay (40%). Gravel 1-3mm; angular - sub angular. Minor calcreteclasts upto 3mm. Silty.

Gravel: Red brown gravel; angular - sub angular.Trace of calcrete; sub angular. Minor clays.Large gravel clasts upto 40mm @ 54m.

Gravel: Red brown black fine - medium grainedgravel; angular - sub angular. Minor calcrete.Minor magnetite.

Gravel: Khaki grey/red brown gravel with clastsupto 30mm; angular - sub angular. Minor quartzupto 20mm. Minor calcrete and magnetite.

Gravel: Brown red grey gravel with angular rockclasts upto 40mm. Minor calcrete clasts upto20mm. Minor clay.

Saprock: Khaki grey green gravel; angular - subangula. Rock clasts upto 20mm. Clay (50%).

Saprock: Khaki green gravel; angular - subangular. Weathered rock clasts upto 80mm; subangular.

Ultra Mafic: Green blue weathered igneousangular-subangular, clasts upto 40mm. Minorgravels at 92-96m

Ore: Dark blue weathered basalt angular-subangular. Minor gravels. High ore content. Minorquartz; angular - sub angular.

2-4m Bentonite Seal








Project:Client:

Logged By:

COMPOSITE WELL LOG

Drilled:

Commenced:S




Easting:

Northing:

Bore No:

Static Water Level:

Elevation:

Remarks:

Area:


Completed:

WA 6005

Aq

uif

er

+61 8 93215594

West Perth

85 Havelock St

Method:

Bit Record:

File Ref: Well No:

0

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170

180

190


29/06/2019

8/07/2019

Ausdrill North West

LC

15.64 mbtoc

469 mRL

663418

7016082

0.82m Stick up

Orebody

GDA94 zone 50J

19AVWP001

DR 0-94m

DDH 94-184m

346mm(0-94m)/298mm(94-184m)

F:\183\2.TECH\LogPlot 19AVWP001

FWS






Airlift yield = 1 L/s, EC =135000 mS/cm


Airlift yield = 5.5 L/s, EC= 193000 mS/cm



Airlift yield = 10 L/s, EC= 322000 mS/cm




Duricrust: Red brown, silty sand and gravel.Sand; fine grained. Gravek; ang to sub angclasts up to 30mm. High magnetite content.Large clasts of ultra mafics.

Gravel: Red - brown, silty. Gravel; ang to subang. 20% clay.

Clay: With minor gravel (20%).

Gravel and Clay: 50% gravel; red brown, ang tosub ang. 50% clay.

Saprolite: Red - brown, silty. Puggy clay withgravel. High magnetite content.

Saprock: Weathered igneous rock with minorgravels. Clasts up to 50mm; ang to sub ang.Clay 30%.

Saprock: Red black medium - coarse grained;sub rounded - sub ang. 50% ore 50% gravel.

Saprock: Weathered ignenous rock with minorgravels. Clasts upto 10mm. High magnetitecontent. 40% clay - becoming hard andgreen/yellow @ 70m.

Saprock: Yellow - green- grey stiff mottled clay(70%). Weathered igneous rock/gravel ang - subang. High magnetite content.

Ultra Mafic: Weathered igneous rock (basalt?)purple - dark green. Minor clay increasing @96m. High magentite content. Minor Quartz -ang to sub ang, weathered.

Ore: Black metallic magnetite; ang to sub angfine grained with large clasts upto 30mm (80%).Weathered igneous rock (20%).Limitted Quartzand high sulphide content (pyrite).

Basement: Grey green weathered ignenousrock. Quartz; ang to sub ang. Minor gravel.Minor clay - stiff. Minor fine grained magnetite.

2-4m Bentonite Seal




Project:Client:

Logged By:

COMPOSITE WELL LOG

Drilled:

Commenced:S




Easting:

Northing:

Bore No:

Static Water Level:

Elevation:

Remarks:

Area:


Completed:

WA 6005

Aq

uif

er

+61 8 93215594

West Perth

85 Havelock St

Method:

Bit Record:

File Ref: Well No:

0

10

20

30


10/07/2019

11/07/2019

Ausdrill North West

LC

8.15 mbtoc

464 mRL

663545

7011754

0.41m Stick up

Palaeochannel

GDA94 zone 50J

19AVWP002

DR 0-28m

346mm

F:\183\2.TECH\LogPlot 19AVWP002

Airlift = 15 L/s, EC =13240 mS/cm, pH =7.74

Airlift = 20 L/s, EC =13790 mS/cm, pH =7.71

Completion Airlift = 15L/s

Soil: Surficial soil with rock fragments. Redbrown, angluar caprock and silty soils.

Gravel: Sandy. Tan/khaki clay, silt and rockfragments 10-40mm.

Calcrete: Ivory calcrete with brown coarse sandand gravel 1-8mm. CaCO3 80%.

Gravel and Sand: Brown sandy gravel and clay(30%). Rock fragments 10-25mm.

Clay: Red brown clay with sandy gravel. Clay80%.

2-4m Bentonite Seal

0-16m Blank 200mmND PVC Class 18


16-28m 1mm Slotted200mm ND PVCClass 18

APPENDIX C

HYDRAULIC TESTING PLOTS

FALLING HEAD TEST

Bore No: 19AVWM01 Test No: 1 Job No: 183 Date: 10-Aug-19 Logged by: EE/ZA

Depth to top of test section (m): 98 Length of test section, L (m): 3

Depth of static water level, Hw (m): 14.14 Radius of borehole, r (m): 0.1

Excess head, he (m): 13.04 Radius of standpipe or casing, rc (m): 0.025

Calculations:

h1 1.000 1.000

t1 0.00 0.000

h2 0.200 0.800

t2 5.00 30.00

S 1.4E-01 3.2E-03

k 3.87E-06 8.95E-08

m/d 3.35E-01 7.73E-03

Permeability, k = 0.133 x S x (rc2/L), (m/sec)

Notes:

where S = (log (h1/h2)/(t2 - t1),

(ie slope of plot, t in mins)

Head - time graph (slope of graph is S)

0.100

1.000

0 5 10 15 20 25 30 35

ht/h

e

Time (min)

F:\183\2.TECH\Aquifer Testing\Analysis\19AVWM01_slug_analysis

Airlift Hydraulic TestF:\183\3.C&R\048 Figs & App\App C_Hydraulic Testing Plots\[Airlift Tests.xlsx]19AVWM02s&d

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1 10 100 1000 10000

Dra

wd

ow

n (

m)

Time (secs)

19AVWM02s

0

1

2

3

4

5

6

7

8

1 10 100 1000 10000

Dra

wd

ow

n (

m)

Time (secs)

19AVWM02d

Airlift Hydraulic TestF:\183\3.C&R\048 Figs & App\App C_Hydraulic Testing Plots\[Airlift Tests.xlsx]19AVWM03

0

0.5

1

1.5

2

2.5

3

1 10 100 1000 10000

Dra

wd

ow

n (

m)

Time (secs)

19AVWM03

Airlift Hydraulic TestF:\183\3.C&R\048 Figs & App\App C_Hydraulic Testing Plots\[Airlift Tests.xlsx]19AVWM104 & 114

0

1

2

3

4

5

6

1 10 100 1000 10000

Dra

wd

ow

n (

m)

Time (secs)

19AVWM104

0

1

2

3

4

5

6

7

1 10 100 1000 10000

Dra

wd

ow

n (

m)

Time (secs)

19AVWM114

FALLING HEAD TEST





Calculations:

h1 1.000 0.060

t1 0.00 0.000

h2 0.001 0.010

t2 5.00 27.50

S 6.0E-01 2.8E-02

k 3.20E-07 1.51E-08

m/d 2.76E-02 1.30E-03


Notes:

where S = (log (h1/h2)/(t2 - t1),



0.001

0.010

0.100

1.000

0 5 10 15 20 25 30 35

ht/h

e

Time (min)

F:\183\2.TECH\Aquifer Testing\Analysis\19AVWM108_slug_analysis

FALLING HEAD TEST





Calculations:

h1 1.000 0.697

t1 0.00 1.000

h2 0.862 0.308

t2 0.10 10.07

S 6.5E-01 3.9E-02

k 4.07E-07 2.46E-08

m/d 3.52E-02 2.12E-03


Notes:

where S = (log (h1/h2)/(t2 - t1),



0.010

0.100

1.000

0 5 10 15 20 25 30 35

ht/h

e

Time (min)

F:\183\2.TECH\Aquifer Testing\Analysis\19AVWM113_slug_analysis_RevB

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

0.1 1.0 10.0 100.0 1,000.0 10,000.0

Dra

wd

ow

n (

me

ters

)

Duration (minutes)

19AVWP001 Constant Rate Test Chart

19AVWP001

19AVWM105

Increased Rate

Replotted

Test Start: 10/8/19

Rate: 5L/s for 48 hrs

Increased Rate to

8L/s after 48 hrs

(2880 mins)

Discharge Short Term Long Term Interference Total Pumping

(kL/d) Drawdown

(m)

Drawdown

(m)

Effects

(m)

Drawdown

(m) Water Level

(mbgl)

0 0 0 0 0 15.60

346 33.77 20.56 0.00 54.33 69.93

518 52.61 30.78 0.00 83.39 98.99

691 72.93 41.05 0.00 113.98 129.58

864 94.63 51.33 0.00 145.96 161.56

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

160.00

180.00

0 100 200 300 400 500 600 700 800 900 1000

Wa

ter

Le

ve

l (m

bg

l)

Discharge (kL/d)

19AVWP001: Bore Performance and Deployable Yield

Predicted Pumping WL Max Pumping WL Avg SWL

sw(n) = BQn + CQnP (Rorabaugh's equation)

Where: B = Intercept with y axis (coefficient of aquifer loss or laminar flow)

C = Gradient (coefficient of turbulent flow loss or apparent well loss)

s = Drawdown in the borehole

P = Value determined using Rorabaugh's method of superposition

Components of Jacob's (1947) equation BQ and CQ2 are termed the aquifer loss and apparent well loss respectively.

They give an indication of the proportion of total drawdown caused by laminar and turbulent flow.

Please note: 1. In thin or fissured aquifers large components of well loss are due to high flow velocities in the aquifer

rather than inefficient bore design. Therefore, the term "apparent well loss" is better than well loss.

2. In aquifers where the flow horizons are vertically anisotropic, changes in bore performance often

relate to changes in the rest water level with respect to the primary aquifer horizons.

Ew = (BQ/(BQ + CQP) x 100

Ew or Well Efficiency represents the proportion of drawdown caused by laminar flow

From plot of s/Q v Q (trend line equation): Intercept (B) 8.965E-02

Gradient (C) 2.300E-05

ANALYSIS TABLE

Measured

Step Discharge Discharge (Q) Incremental Corrected Predicted Apparent

(60 minute (l/s) (m3/d) Drawdown Drawdown Drawdown s/Q Efficiency (Ew)

duration) (metres) (metres) (metres) %

1 2.0 173 16.00 16.00 16.18 9.26E-02 95.8

2 4.0 346 18.00 34.00 33.73 9.84E-02 91.9

3 6.0 518 19.45 53.45 52.65 1.03E-01 88.3

4 8.0 691 18.62 72.07 72.95 1.04E-01 84.9

Calculation of well efficiency and comparison of observed and predicted drawdowns

0

10

20

30

40

50

60

70

800.1 1 10 100 1000

Dra

wd

ow

n (

m)

Time (minutes)

19AVWP001: Step Discharge Pumping Test

y = 2.300E-05x + 8.965E-02

0.0E+00

2.0E-02

4.0E-02

6.0E-02

8.0E-02

1.0E-01

1.2E-01

0 100 200 300 400 500 600 700 800

s (

m)

/ Q

(m

3/d

ay)

Q (m3/day)

Analytical Plot of s/Q v Q

B = y intercept (coefficient of aquifer loss)

C = Gradient (coefficient of well loss)

s = BQ +CQ2

0.00

1.00

2.00

3.00

1.0 10.0 100.0 1,000.0 10,000.0

Dra

wd

ow

n (

me

ters

)

Duration (minutes)

19AVWP002 Constant Rate Test Chart

19AVWP002

19AVWM104

Test Start: 4/8/19

Rate: 10L/s

Duration: 30 hrs

(1800 mins)

Discharge Short Term Long Term Interference Total Pumping

(kL/d) Drawdown

(m)

Drawdown

(m)

Effects

(m)

Drawdown

(m) Water Level

(mbgl)

0 0 0 0 0 8.15

864 2.10 1.47 0.00 3.57 11.72

1296 3.59 2.21 0.00 5.80 13.95

1728 5.36 2.94 0.00 8.31 16.46

2160 7.43 3.68 0.00 11.11 19.26

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

16.00

18.00

20.00

0 500 1000 1500 2000 2500

Wa

ter

Le

ve

l (m

bg

l)

Discharge (kL/d)

19AVWP002: Bore Performance and Deployable Yield

Predicted Pumping WL Max Pumping WL Avg SWL

sw(n) = BQn + CQnP (Rorabaugh's equation)

Where: B = Intercept with y axis (coefficient of aquifer loss or laminar flow)

C = Gradient (coefficient of turbulent flow loss or apparent well loss)

s = Drawdown in the borehole

P = Value determined using Rorabaugh's method of superposition

Components of Jacob's (1947) equation BQ and CQ2 are termed the aquifer loss and apparent well loss respectively.

They give an indication of the proportion of total drawdown caused by laminar and turbulent flow.

Please note: 1. In thin or fissured aquifers large components of well loss are due to high flow velocities in the aquifer

rather than inefficient bore design. Therefore, the term "apparent well loss" is better than well loss.

2. In aquifers where the flow horizons are vertically anisotropic, changes in bore performance often

relate to changes in the rest water level with respect to the primary aquifer horizons.

Ew = (BQ/(BQ + CQP) x 100

Ew or Well Efficiency represents the proportion of drawdown caused by laminar flow

From plot of s/Q v Q (trend line equation): Intercept (B) 1.764E-03

Gradient (C) 7.757E-07

ANALYSIS TABLE

Measured

Step Discharge Discharge (Q) Incremental Corrected Predicted Apparent

(60 minute (l/s) (m3/d) Drawdown Drawdown Drawdown s/Q Efficiency (Ew)

duration) (metres) (metres) (metres) %

1 10.0 864 2.09 2.09 2.10 2.42E-03 72.5

2 15.0 1296 1.52 3.61 3.59 2.79E-03 63.7

3 20.0 1728 1.76 5.37 5.36 3.11E-03 56.8

4 25.0 2160 2.04 7.41 7.43 3.43E-03 51.3

Calculation of well efficiency and comparison of observed and predicted drawdowns

0123456789

100.1 1 10 100 1000

Dra

wd

ow

n (

m)

Time (minutes)

19AVWP002: Step Discharge Pumping Test

y = 7.757E-07x + 1.764E-03

0.0E+00

5.0E-04

1.0E-03

1.5E-03

2.0E-03

2.5E-03

3.0E-03

3.5E-03

4.0E-03

0 500 1000 1500 2000 2500

s (

m)

/ Q

(m

3/d

ay)

Q (m3/day)

Analytical Plot of s/Q v Q

B = y intercept (coefficient of aquifer loss)

C = Gradient (coefficient of well loss)

s = BQ +CQ2

1. 10. 100. 1000. 1.0E+40.

0.8

1.6

2.4

3.2

4.

Adjusted Time (sec)

Corr

ecte

d D

ispla

cem

ent (m

)

WELL TEST ANALYSIS

Data Set: F:\183\2.TECH\Field Data\AQTESOLV\GHD912.aqtDate: 08/13/18 Time: 14:14:39

PROJECT INFORMATION

Company: AQ2Client: AVLProject: 183Location: GabaninthaTest Well: GDH912

AQUIFER DATA

Saturated Thickness: 156.1 m Anisotropy Ratio (Kz/Kr): 0.1

WELL DATA

Pumping WellsWell Name X (m) Y (m)GDH912 0 0

Observation WellsWell Name X (m) Y (m)

GDH912 0 0

SOLUTION

Aquifer Model: Unconfined Solution Method: Cooper-Jacob

T = 0.6417 m2/day S = 0.3366

1. 10. 100. 1000. 1.0E+40.

0.8

1.6

2.4

3.2

4.

Adjusted Time (sec)

Corr

ecte

d D

ispla

cem

ent (m

)

WELL TEST ANALYSIS


PROJECT INFORMATION


AQUIFER DATA

Saturated Thickness: 124. m Anisotropy Ratio (Kz/Kr): 0.1

WELL DATA



GDH911 0 0

SOLUTION


T = 0.2906 m2/day S = 0.3672

1. 10. 100. 1000. 1.0E+40.

0.04

0.08

0.12

0.16

0.2

Adjusted Time (sec)

Corr

ecte

d D

ispla

cem

ent (m

)

WELL TEST ANALYSIS


PROJECT INFORMATION


AQUIFER DATA


WELL DATA



GDH914 0 0

SOLUTION


T = 0.4649 m2/day S = 0.1194

1. 10. 100. 1000. 1.0E+40.

0.4

0.8

1.2

1.6

2.

Adjusted Time (sec)

Corr

ecte

d D

ispla

cem

ent (m

)

WELL TEST ANALYSIS


PROJECT INFORMATION


AQUIFER DATA


WELL DATA



GDH904 0 0

SOLUTION


T = 0.4817 m2/day S = 0.1966

1. 10. 100. 1000. 1.0E+4-0.08

-0.004

0.072

0.148

0.224

0.3

Adjusted Time (sec)

Corr

ecte

d D

ispla

cem

ent (m

)

WELL TEST ANALYSIS

Data Set: F:\183\2.TECH\Field Data\AQTESOLV\GRC0161.aqtDate: 08/13/18 Time: 14:05:04

PROJECT INFORMATION

Company: AQ2Client: AVLProject: 183Location: GabaninthaTest Well: GRC0161

AQUIFER DATA


WELL DATA

Pumping WellsWell Name X (m) Y (m)GRC0161 0 0


GRC0161 0 0

SOLUTION


T = 1.365 m2/day S = 0.2894

1. 10. 100. 1000. 1.0E+40.

0.6

1.2

1.8

2.4

3.

Adjusted Time (sec)

Corr

ecte

d D

ispla

cem

ent (m

)

WELL TEST ANALYSIS


PROJECT INFORMATION


AQUIFER DATA


WELL DATA



GRC0165 0 0

SOLUTION


T = 0.5051 m2/day S = 0.4928

1. 10. 100. 1000. 1.0E+40.001

0.01

0.1

1.

10.

Time (sec)

Corr

ecte

d D

ispla

cem

ent (m

)

WELL TEST ANALYSIS


PROJECT INFORMATION


WELL DATA



GRC0169 0 0

SOLUTION

Aquifer Model: Unconfined Solution Method: Theis

T = 0.2789 m2/day S = 0.3761Kz/Kr = 0.1 b = 47. m

1. 10. 100. 1000. 1.0E+40.01

0.1

Time (sec)

Corr

ecte

d D

ispla

cem

ent (m

)

WELL TEST ANALYSIS


PROJECT INFORMATION


WELL DATA



GRC0180 0 0

SOLUTION

Aquifer Model: Unconfined Solution Method: Theis

T = 52.63 m2/day S = 1.026Kz/Kr = 0.1 b = 100. m

APPENDIX D

WATER QUALITY ANALYSES

Accreditation No. 2562

Date Reported

Contact

SGS Perth Environmental

28 Reid Rd

Perth Airport WA 6105

Ros Ma

(08) 9373 3500

(08) 9373 3556

[email protected]

7

SGS Reference

Email

Facsimile

Telephone

Address

Manager

Laboratory

183 Gabanintha

183 Gabanintha

[email protected]

(Not specified)

0417 183224

PO BOX 976

SOUTH PERTH WA 6951

AQ2

Alex Storey

Samples

Order Number

Project

Email

Facsimile

Telephone

Address

Client

CLIENT DETAILS LABORATORY DETAILS

10 Aug 2018

ANALYTICAL REPORT

PE127757 R0

06 Aug 2018Date Received

Accredited for compliance with ISO/IEC 17025 - Testing. NATA accredited laboratory 2562(898/20210).

For determination of soluble metals, filtered sample was not received so samples were laboratory filtered on receipt. This may give soluble metals

results that do not represent the concentrations present at the time of sampling.

Metals: Dissolved Na: Spike recovery failed acceptance criteria due to the presence of significant concentration of analyte (i.e. the concentration

of analyte exceeds the spike level).

Ionic Balance: #4 is outside acceptance criteria due sample heterogeneity.

COMMENTS

Hue Thanh Ly

Metals Team Leader

Mary Ann Ola-A

Inorganics Team Leader

SIGNATORIES

SGS Australia Pty Ltd

ABN 44 000 964 278

Environment, Health and Safety 28 Reid Rd

PO Box 32


Welshpool WA 6983

Australia

Australia

t +61 8 9373 3500

f +61 8 9373 3556

www.sgs.com.au

Member of the SGS Group

Page 1 of 710-August-2018

PE127757 R0ANALYTICAL REPORT

PE127757.001

Water

8/7/18 11:00

GDH904

PE127757.002

Water

2/8/18 11:30

GDH911

PE127757.003

Water

1/8/18 8:00

GDH912

PE127757.004

Water

2/8/18 10:00

GDH914

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name

pH in water Method: AN101 Tested: 6/8/2018

pH** No unit 0.1 7.4 7.7 7.7 7.7

Conductivity and TDS by Calculation - Water Method: AN106 Tested: 6/8/2018

Conductivity @ 25 C µS/cm 2 31000 4400 9400 6700

Alkalinity Method: AN135 Tested: 6/8/2018

Total Alkalinity as CaCO3 mg/L 5 97 230 220 180

Carbonate Alkalinity as CO3 mg/L 1 <1 <1 <1 <1

Bicarbonate Alkalinity as HCO3 mg/L 5 120 280 270 220

Chloride by Discrete Analyser in Water Method: AN274 Tested: 6/8/2018

Chloride, Cl mg/L 1 10000 1100 2800 1900

Sulfate in water Method: AN275 Tested: 6/8/2018

Sulfate, SO4 mg/L 1 2200 310 660 580

Metals in Water (Dissolved) by ICPOES Method: AN320 Tested: 7/8/2018

Calcium, Ca mg/L 0.2 440 93 92 94

Magnesium, Mg mg/L 0.1 1100 160 250 170

Potassium, K mg/L 0.1 230 11 55 25

Sodium, Na mg/L 0.5 4700 570 1600 750



PE127757.005

Water

1/8/18 11:00

GRC161

PE127757.006

Water

2/8/18 7:45

GRC0169

PE127757.007

Water

1/8/18 13:00

GRC0180

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name


pH** No unit 0.1 7.8 7.8 7.9


Conductivity @ 25 C µS/cm 2 5200 2300 2600


Total Alkalinity as CaCO3 mg/L 5 180 240 210

Carbonate Alkalinity as CO3 mg/L 1 <1 <1 <1

Bicarbonate Alkalinity as HCO3 mg/L 5 220 290 260


Chloride, Cl mg/L 1 1400 470 550


Sulfate, SO4 mg/L 1 390 140 180


Calcium, Ca mg/L 0.2 110 77 62

Magnesium, Mg mg/L 0.1 180 87 85

Potassium, K mg/L 0.1 25 13 12

Sodium, Na mg/L 0.5 690 260 350


PE127757 R0QC SUMMARY

MB blank results are compared to the Limit of Reporting

LCS and MS spike recoveries are measured as the percentage of analyte recovered from the sample compared the the amount of analyte spiked into the sample.

DUP and MSD relative percent differences are measured against their original counterpart samples according to the formula : the absolute difference of the two results divided

by the average of the two results as a percentage. Where the DUP RPD is 'NA' , the results are less than the LOR and thus the RPD is not applicable.

Alkalinity Method: ME-(AU)-[ENV]AN135

MB DUP %RPD LCS

%Recovery

Total Alkalinity as CaCO3 LB149123 mg/L 5 <5 1 - 5% 99%

Carbonate Alkalinity as CO3 LB149123 mg/L 1 <1

Bicarbonate Alkalinity as HCO3 LB149123 mg/L 5 <5

LORUnits Parameter QC

Reference

Chloride by Discrete Analyser in Water Method: ME-(AU)-[ENV]AN274

MB DUP %RPD LCS

%Recovery

MS

%Recovery

Chloride, Cl LB149034 mg/L 1 <1 0 - 1% 105% 86 - 100%


Reference

Conductivity and TDS by Calculation - Water Method: ME-(AU)-[ENV]AN106

MB DUP %RPD LCS

%Recovery

Conductivity @ 25 C LB149130 µS/cm 2 <2 0 - 1% 99 - 100%

LB149131 µS/cm 2 <2 0 - 1% 99%


Reference

Metals in Water (Dissolved) by ICPOES Method: ME-(AU)-[ENV]AN320

MB DUP %RPD LCS

%Recovery

MS

%Recovery

Calcium, Ca LB149048 mg/L 0.2 <0.2 0% 101% 102%

Magnesium, Mg LB149048 mg/L 0.1 <0.1 0 - 1% 100% 107%

Potassium, K LB149048 mg/L 0.1 <0.1 1% 101% 104%

Sodium, Na LB149048 mg/L 0.5 <0.5 1% 99% 166%


Reference

pH in water Method: ME-(AU)-[ENV]AN101

MB DUP %RPD LCS

%Recovery

pH** LB149130 No unit 0.1 5.7 - 6.6 0 - 1% 100%

LB149131 No unit 0.1 5.9 0% 100%


Reference







Sulfate in water Method: ME-(AU)-[ENV]AN275

MB DUP %RPD LCS

%Recovery

MS

%Recovery

Sulfate, SO4 LB149034 mg/L 1 <1 0% 99% 95 - 96%


Reference


PE127757 R0

METHOD METHODOLOGY SUMMARY

METHOD SUMMARY

pH in Soil Sludge Sediment and Water: pH is measured electrometrically using a combination electrode (glass plus

reference electrode) and is calibrated against 3 buffers purchased commercially. For soils, an extract with water is

made at a ratio of 1:5 and the pH determined and reported on the extract. Reference APHA 4500-H+.

AN101

Conductivity and TDS by Calculation: Conductivity is measured by meter with temperature compensation and is

calibrated against a standard solution of potassium chloride. Conductivity is generally reported as µmhos/cm or

µS/cm @ 25°C. For soils, an extract with water is made at a ratio of 1:5 and the EC determined and reported on

the extract, or calculated back to the as-received sample. Total Dissolved Salts can be estimated from conductivity

using a conversion factor, which for natural waters, is in the range 0.55 to 0.75. SGS use 0.6. Reference APHA

2510 B.

AN106

Salinity may be calculated in terms of NaCl from the sample conductivity. This assumes all soluble salts present,

measured by the conductivity, are present as NaCl.

AN106

This method is used to calculation the balance of major Anions and Cations in water samples and converts major

ion concentration to milliequivalents and then summed. Anions sum and Cation sum is calculated as a difference

and expressed as a percentage.

AN121

The sum of cations and anions in mg/L may also be reported. This sums Na, K, Ca, Mg, NH3, Fe, Cl, Total

Alkalinity, SO4 and NO3.

AN121

Alkalinity (and forms of) by Titration: The sample is titrated with standard acid to pH 8.3 (P titre) and pH 4.5 (T titre)

and permanent and/or total alkalinity calculated. The results are expressed as equivalents of calcium carbonate or

recalculated as bicarbonate, carbonate and hydroxide. Reference APHA 2320. Internal Reference AN135

AN135

Chloride by Aquakem DA: Chloride reacts with mercuric thiocyanate forming a mercuric chloride complex. In the

presence of ferric iron, highly coloured ferric thiocyanate is formed which is proportional to the chloride

concentration. Reference APHA 4500Cl-

AN274

sulfate by Aquakem DA: sulfate is precipitated in an acidic medium with barium chloride. The resulting turbidity is

measured photometrically at 405nm and compared with standard calibration solutions to determine the sulfate

concentration in the sample. Reference APHA 4500-SO42-. Internal reference AN275.

AN275

Metals by ICP-OES: Samples are preserved with 10% nitric acid for a wide range of metals and some non-metals.

This solution is measured by Inductively Coupled Plasma. Solutions are aspirated into an argon plasma at

8000-10000K and emit characteristic energy or light as a result of electron transitions through unique energy

levels. The emitted light is focused onto a diffraction grating where it is separated into components .

AN320

Photomultipliers or CCDs are used to measure the light intensity at specific wavelengths. This intensity is directly

proportional to concentration. Corrections are required to compensate for spectral overlap between elements.

Reference APHA 3120 B.

AN320

Free and Total Carbon Dioxide may be calculated using alkalinity forms only when the samples TDS is <500mg/L.

If TDS is >500mg/L free or total carbon dioxide cannot be reported . APHA4500CO2 D.

Calculation


PE127757 R0

Samples analysed as received.

Solid samples expressed on a dry weight basis.

Where "Total" analyte groups are reported (for example, Total PAHs, Total OC Pesticides) the total will be calculated as the sum of the individual

analytes, with those analytes that are reported as <LOR being assumed to be zero. The summed (Total) limit of reporting is calcuated by summing

the individual analyte LORs and dividing by two. For example, where 16 individual analytes are being summed and each has an LOR of 0.1 mg/kg,

the "Totals" LOR will be 1.6 / 2 (0.8 mg/kg). Where only 2 analytes are being summed, the " Total" LOR will be the sum of those two LORs.

Some totals may not appear to add up because the total is rounded after adding up the raw values.

If reported, measurement uncertainty follow the ± sign after the analytical result and is expressed as the expanded uncertainty calculated using a

coverage factor of 2, providing a level of confidence of approximately 95%, unless stated otherwise in the comments section of this report.

Results reported for samples tested under test methods with codes starting with ARS -SOP, radionuclide or gross radioactivity concentrations are

expressed in becquerel (Bq) per unit of mass or volume or per wipe as stated on the report. Becquerel is the SI unit for activity and equals one

nuclear transformation per second.

Note that in terms of units of radioactivity:

a. 1 Bq is equivalent to 27 pCi

b. 37 MBq is equivalent to 1 mCi

For results reported for samples tested under test methods with codes starting with ARS -SOP, less than (<) values indicate the detection limit for

each radionuclide or parameter for the measurement system used. The respective detection limits have been calculated in accordance with ISO

11929.

The QC criteria are subject to internal review according to the SGS QAQC plan and may be provided on request or alternatively can be found here :

http://www.sgs.com.au/~/media/Local/Australia/Documents/Technical%20Documents/MP-AU-ENV-QU-022%20QA%20QC%20Plan.pdf

This document is issued by the Company under its General Conditions of Service accessible at www.sgs.com/en/Terms-and-Conditions.aspx.

Attention is drawn to the limitation of liability, indemnification and jurisdiction issues defined therein.

Any holder of this document is advised that information contained hereon reflects the Company 's findings at the time of its intervention only and

within the limits of Client's instructions, if any. The Company's sole responsibility is to its Client only. Any unauthorized alteration, forgery or

falsification of the content or appearance of this document is unlawful and offenders may be prosecuted to the fullest extent of the law .

This report must not be reproduced, except in full.

IS

LNR

*

**

Insufficient sample for analysis.

Sample listed, but not received.

NATA accreditation does not cover the

performance of this service.

Indicative data, theoretical holding time exceeded.

FOOTNOTES

LOR

↑↓

QFH

QFL

-

NVL

Limit of Reporting

Raised or Lowered Limit of Reporting

QC result is above the upper tolerance

QC result is below the lower tolerance

The sample was not analysed for this analyte

Not Validated



Date Reported

Contact


28 Reid Rd


Marjana Siljanoska

(08) 9373 3500

(08) 9373 3556

[email protected]

1

SGS Reference

Email

Facsimile

Telephone

Address

Manager

Laboratory

183C C2

183C C2

[email protected]

(Not specified)

0417 183224

PO BOX 976

SOUTH PERTH WA 6951

AQ2

Duncan Storey

Samples

Order Number

Project

Email

Facsimile

Telephone

Address

Client


17 May 2019

ANALYTICAL REPORT

PE134594 R0

02 May 2019Date Received


For determination of soluble metals, filtered sample was not received so samples were laboratory subsampled and filtered on receipt. This may

give soluble metals results that do not represent the concentrations present at the time of sampling.

Metals: LORs raised due to high conductivity.

The upper limit for Conductivity in Water is 100,000 uS/cm. Any result above this is an estimate. This will also cause the TDS on EC ratio to bias

high.

COMMENTS

Hue Thanh Ly

Metals Team Leader

Louise Hope

Laboratory Technician

SIGNATORIES


ABN 44 000 964 278


PO Box 32


Welshpool WA 6983

Australia

Australia

t +61 8 9373 3500

f +61 8 9373 3556

www.sgs.com.au


Page 1 of 717-May-2019


PE134594.001

Water

27 Apr 2019

19AVWM01

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name


pH** pH Units - 7.2


Conductivity @ 25 C µS/cm 2 180000

Total Dissolved Solids (TDS) in water Method: AN113 Tested: 7/5/2019

Total Dissolved Solids Dried at 175-185°C mg/L 10 140000


Total Alkalinity as CaCO3 mg/L 5 47

Carbonate Alkalinity as CO3 mg/L 1 <1

Bicarbonate Alkalinity as HCO3 mg/L 5 58


Chloride, Cl mg/L 1 88000


Sulfate, SO4 mg/L 1 19000



PE134594.001

Water

27 Apr 2019

19AVWM01

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name


Calcium, Ca mg/L 0.2 840

Magnesium, Mg mg/L 0.1 6400

Potassium, K mg/L 0.1 2800

Sodium, Na mg/L 0.5 46000








MB DUP %RPD LCS

%Recovery

Total Alkalinity as CaCO3 LB159059 mg/L 5 <5 7% 99%




Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery

Chloride, Cl LB159390 mg/L 1 <1 0 - 4% 109 - 110% 99%


Reference


MB DUP %RPD LCS

%Recovery

Conductivity @ 25 C LB159107 µS/cm 2 <2 0 - 3% 107%


Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery

Calcium, Ca LB159002 mg/L 0.2 <0.2 1% 97% 91%

Magnesium, Mg LB159002 mg/L 0.1 <0.1 0% 97% 90%


Sodium, Na LB159002 mg/L 0.5 <0.5 1% 100% 85%


Reference


MB LCS

%Recovery

pH** LB159107 pH Units - 5.7 100%


Reference








MB DUP %RPD LCS

%Recovery

MS

%Recovery

Sulfate, SO4 LB159497 mg/L 1 <1 0 - 2% 107 - 108% 86 - 95%


Reference

Total Dissolved Solids (TDS) in water Method: ME-(AU)-[ENV]AN113

MB DUP %RPD LCS

%Recovery

MS

%Recovery

MSD %RPD

Total Dissolved Solids Dried at 175-185°C LB159173 mg/L 10 <10 1% 96% 99% 1%


Reference


PE134594 R0


METHOD SUMMARY




AN101






2510 B.

AN106



AN106

Total Dissolved Solids: A well-mixed filtered sample of known volume is evaporated to dryness at 180°C and the

residue weighed. Approximate methods for correlating chemical analysis with dissolved solids are available.

Reference APHA 2540 C.

AN113

The Total Dissolved Solids residue may also be ignited at 550 C and volatile TDS (Organic TDS) and non-volatile

TDS (Inorganic) can be determined.

AN113




AN135




AN274




AN275





AN320




AN320



Calculation


PE134594 R0

Unless it is reported that sampling has been perfomed by SGS, the samples have been analysed as received.

















11929.

The QC and MU criteria are subject to internal review according to the SGS QAQC plan and may be provided on request or alternatively can be

found here: www.sgs.com.au.pv.sgsvr/en-gb/environment.







IS

LNR

*

**






FOOTNOTES

LOR

↑↓

QFH

QFL

-

NVL

Limit of Reporting





Not Validated



Date Reported

Contact


28 Reid Rd


Marjana Siljanoska

(08) 9373 3500

(08) 9373 3556

[email protected]

1

SGS Reference

Email

Facsimile

Telephone

Address

Manager

Laboratory

183C C2

183CAVL C2

[email protected]

(Not specified)

61 8 93238821

PO BOX 976

SOUTH PERTH WA 6951

AQ2

Liam Storey

Samples

Order Number

Project

Email

Facsimile

Telephone

Address

Client


28 May 2019

ANALYTICAL REPORT

PE134996 R0

17 May 2019Date Received




COMMENTS

Hue Thanh Ly

Metals Team Leader

Louise Hope


Mary Ann Ola-A


SIGNATORIES


ABN 44 000 964 278


PO Box 32


Welshpool WA 6983

Australia

Australia

t +61 8 9373 3500

f +61 8 9373 3556

www.sgs.com.au




PE134996.001

Water

14/5/19 12:15

19AVWM02S

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name


pH** No unit 0.1 8.0















PE134996.001

Water

14/5/19 12:15

19AVWM02S

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name













MB DUP %RPD LCS

%Recovery





Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery

Chloride, Cl LB159837 mg/L 1 <1 0 - 3% 107 - 108% 90 - 98%


Reference


MB DUP %RPD LCS

%Recovery

Conductivity @ 25 C LB159762 µS/cm 2 <2 0% 104%


Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery

Calcium, Ca LB159589 mg/L 0.2 <0.2 1% 101% 102%



Sodium, Na LB159589 mg/L 0.5 <0.5 2% 98% 98%


Reference


MB DUP %RPD LCS

%Recovery

pH** LB159762 No unit 0.1 5.6 2% 101%


Reference








MB DUP %RPD LCS

%Recovery

MS

%Recovery

Sulfate, SO4 LB159837 mg/L 1 <1 0 - 2% 106 - 108% 90 - 91%


Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery

MSD %RPD

Total Dissolved Solids Dried at 175-185°C LB159575 mg/L 10 <10 1 - 8% 98% 101% 3%


Reference


PE134996 R0


METHOD SUMMARY




AN101






2510 B.

AN106



AN106




AN113



AN113




AN135




AN274




AN275





AN320




AN320



Calculation


PE134996 R0


















11929.









IS

LNR

*

**






FOOTNOTES

LOR

↑↓

QFH

QFL

-

NVL

Limit of Reporting





Not Validated



Date Reported

Contact


28 Reid Rd


Marjana Siljanoska

(08) 9373 3500

(08) 9373 3556

[email protected]

5

SGS Reference

Email

Facsimile

Telephone

Address

Manager

Laboratory

183C C2

183C AVL C2

[email protected]

(Not specified)

61 8 93238821

PO BOX 976

SOUTH PERTH WA 6951

AQ2

Liam Storey

Samples

Order Number

Project

Email

Facsimile

Telephone

Address

Client


13 Jun 2019

ANALYTICAL REPORT

PE135457 R0

06 Jun 2019Date Received


Metals bottles not received for samples 3 4 5. Subsampled from unpreserved





high.

COMMENTS

Louise Hope


Mary Ann Ola-A


Sanaa Hussain

Chemist

SIGNATORIES


ABN 44 000 964 278


PO Box 32


Welshpool WA 6983

Australia

Australia

t +61 8 9373 3500

f +61 8 9373 3556

www.sgs.com.au


Page 1 of 913-June-2019


PE135457.001

Water

15 May 2019

19AVWM03

PE135457.002

Water

18 May 2019

19AVWM04

PE135457.003

Water

29 May 2019

19AVWM104

PE135457.004

Water

23 May 2019

19AVWM108

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name


pH** pH Units 0.1 8.2 7.9 7.3 8.1


Conductivity @ 25 C µS/cm 2 9200 19000 170000 29000


Total Dissolved Solids Dried at 175-185°C mg/L 10 5000 12000 160000 18000


Bicarbonate Alkalinity as HCO3 mg/L 5 300 140 100 230

Carbonate Alkalinity as CO3 mg/L 5 <5 <5 <5 <5

Hydroxide Alkalinity as OH mg/L 5 <5 <5 <5 <5

Total Alkalinity as CaCO3 mg/L 5 240 110 83 190


Sulfate, SO4 mg/L 1 460 1100 14000 2000


Chloride, Cl mg/L 1 2700 7000 84000 9200



PE135457.001

Water

15 May 2019

19AVWM03

PE135457.002

Water

18 May 2019

19AVWM04

PE135457.003

Water

29 May 2019

19AVWM104

PE135457.004

Water

23 May 2019

19AVWM108

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name


Calcium, Ca mg/L 0.2 110 330 760 330

Magnesium, Mg mg/L 0.1 220 560 5700 890

Potassium, K mg/L 0.1 66 120 2200 160

Sodium, Na mg/L 0.5 1500 3100 43000 4500



PE135457.005

Water

03 Jun 2019

19AVWM105

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name


pH** pH Units 0.1 7.2








Hydroxide Alkalinity as OH mg/L 5 <5








PE135457.005

Water

03 Jun 2019

19AVWM105

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name













MB DUP %RPD LCS

%Recovery


LB160460 mg/L 5 <5


LB160460 mg/L 5 <5

Hydroxide Alkalinity as OH LB160459 mg/L 5 <5

LB160460 mg/L 5 <5


LB160460 mg/L 5 <5 0 - 1% 102%


Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery



Reference


MB DUP %RPD LCS

%Recovery

Conductivity @ 25 C LB160451 µS/cm 2 <2 0 - 1% 100%

LB160452 µS/cm 2 <2 0% 102%


Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery

Calcium, Ca LB160353 mg/L 0.2 <0.2 0% 106% 103%



Sodium, Na LB160353 mg/L 0.5 <0.5 0% 104% 92%


Reference


MB DUP %RPD LCS

%Recovery

pH** LB160451 pH Units 0.1 5.5 0% 101%

LB160452 pH Units 0.1 5.6 - 5.7 0% 100%


Reference








MB DUP %RPD LCS

%Recovery

MS

%Recovery

MSD %RPD

Sulfate, SO4 LB160514 mg/L 1 <1 0 - 4% 102 - 104% 96 - 102% 30%


Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery

MSD %RPD



Reference


PE135457 R0


METHOD SUMMARY




AN101






2510 B.

AN106



AN106




AN113



AN113




AN135




AN274




AN275





AN320




AN320



Calculation


PE135457 R0


















11929.









IS

LNR

*

**






FOOTNOTES

LOR

↑↓

QFH

QFL

-

NVL

Limit of Reporting





Not Validated



Date Reported

Contact


28 Reid Rd


Marjana Siljanoska

(08) 9373 3500

(08) 9373 3556

[email protected]

2

SGS Reference

Email

Facsimile

Telephone

Address

Manager

Laboratory

183C C2

183C AVL C2

[email protected]

(Not specified)

61 8 93238821

PO BOX 976

SOUTH PERTH WA 6951

AQ2

Liam Storey

Samples

Order Number

Project

Email

Facsimile

Telephone

Address

Client


08 Jul 2019

ANALYTICAL REPORT

PE136072 R0

02 Jul 2019Date Received


COMMENTS

Louise Hope


Mary Ann Ola-A


Sanaa Hussain

Chemist

SIGNATORIES


ABN 44 000 964 278


PO Box 32


Welshpool WA 6983

Australia

Australia

t +61 8 9373 3500

f +61 8 9373 3556

www.sgs.com.au


Page 1 of 708-July-2019


PE136072.001

Water

15 Jun 2019

DEB01R

PE136072.002

Water

15 Jun 2019

DEB10

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name


pH** pH Units 0.1 7.8 7.9


Conductivity @ 25 C µS/cm 2 16000 2800


Total Dissolved Solids Dried at 175-185°C mg/L 10 9400 1500


Bicarbonate Alkalinity as HCO3 mg/L 5 260 310

Carbonate Alkalinity as CO3 mg/L 5 <5 <5

Hydroxide Alkalinity as OH mg/L 5 <5 <5

Total Alkalinity as CaCO3 mg/L 5 210 260


Sulfate, SO4 mg/L 1 170 1100


Chloride, Cl mg/L 1 550 4400



PE136072.001

Water

15 Jun 2019

DEB01R

PE136072.002

Water

15 Jun 2019

DEB10

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name


Calcium, Ca mg/L 0.2 160 81

Magnesium, Mg mg/L 0.1 450 110

Potassium, K mg/L 0.1 130 3.7

Sodium, Na mg/L 0.5 2700 310








MB DUP %RPD LCS

%Recovery






Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery



Reference


MB DUP %RPD LCS

%Recovery

Conductivity @ 25 C LB161312 µS/cm 2 <2 1 - 2% 102 - 103%


Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery

Calcium, Ca LB161243 mg/L 0.2 <0.2 2 - 4% 97% 98%

Magnesium, Mg LB161243 mg/L 0.1 <0.1 2 - 4% 101% 98%

Potassium, K LB161243 mg/L 0.1 <0.1 1 - 2% 99% 98%

Sodium, Na LB161243 mg/L 0.5 <0.5 1 - 3% 101% 99%


Reference


MB DUP %RPD LCS

%Recovery

pH** LB161312 pH Units 0.1 5.5 - 5.6 0 - 1% 100%


Reference








MB DUP %RPD LCS

%Recovery

MS

%Recovery

Sulfate, SO4 LB161270 mg/L 1 <1 0 - 4% 99% 96 - 99%


Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery

MSD %RPD



Reference


PE136072 R0


METHOD SUMMARY




AN101






2510 B.

AN106



AN106




AN113



AN113




AN135




AN274




AN275





AN320




AN320



Calculation


PE136072 R0

Unless it is reported that sampling has been performed by SGS, the samples have been analysed as received.

















11929.









IS

LNR

*

**






FOOTNOTES

LOR

↑↓

QFH

QFL

-

NVL

Limit of Reporting





Not Validated



Date Reported

Contact


28 Reid Rd


Marjana Siljanoska

(08) 9373 3500

(08) 9373 3556

[email protected]

2

SGS Reference

Email

Facsimile

Telephone

Address

Manager

Laboratory

183C C2

183C AVL C2

[email protected]

(Not specified)

61 8 93238821

PO BOX 976

SOUTH PERTH WA 6951

AQ2

Emma Bolton

Samples

Order Number

Project

Email

Facsimile

Telephone

Address

Client


29 Jul 2019

ANALYTICAL REPORT

PE136531 R0

19 Jul 2019Date Received






high.

COMMENTS

Louise Hope


Mary Ann Ola-A


Sanaa Hussain

Chemist

SIGNATORIES


ABN 44 000 964 278


PO Box 32


Welshpool WA 6983

Australia

Australia

t +61 8 9373 3500

f +61 8 9373 3556

www.sgs.com.au




PE136531.001

Water

08 Jul 2019

19AVWP001

PE136531.002

Water

13 Jul 2019

19AVWP002

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name


pH** pH Units 0.1 7.3 7.9











Sulfate, SO4 mg/L 1 18000 850





PE136531.001

Water

08 Jul 2019

19AVWP001

PE136531.002

Water

13 Jul 2019

19AVWP002

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name




Potassium, K mg/L 0.1 2500 94

Sodium, Na mg/L 0.5 43000 2300








MB DUP %RPD LCS

%Recovery






Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery



Reference


MB DUP %RPD LCS

%Recovery



Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery

Calcium, Ca LB161925 mg/L 0.2 <0.2 102% 102%


Potassium, K LB161925 mg/L 0.1 <0.1 99% 102%

Sodium, Na LB161925 mg/L 0.5 <0.5 106% 106%


Reference


MB DUP %RPD LCS

%Recovery

pH** LB162006 pH Units 0.1 5.6 - 5.7 0% 100%


Reference








MB DUP %RPD LCS

%Recovery

MS

%Recovery

Sulfate, SO4 LB162042 mg/L 1 <1 0 - 2% 103 - 104% 98 - 113%


Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery

MSD %RPD



Reference


PE136531 R0


METHOD SUMMARY




AN101






2510 B.

AN106



AN106




AN113



AN113




AN135




AN274




AN275





AN320




AN320



Calculation


PE136531 R0


















11929.









IS

LNR

*

**






FOOTNOTES

LOR

↑↓

QFH

QFL

-

NVL

Limit of Reporting





Not Validated



Date Reported

Contact


28 Reid Rd


Marjana Siljanoska

(08) 9373 3500

(08) 9373 3556

[email protected]

2

SGS Reference

Email

Facsimile

Telephone

Address

Manager

Laboratory

183C C2

183C AVL C2

[email protected]

(Not specified)

61 8 93238821

PO BOX 976

SOUTH PERTH WA 6951

AQ2

Emma Bolton

Samples

Order Number

Project

Email

Facsimile

Telephone

Address

Client


23 Aug 2019

ANALYTICAL REPORT

PE137221 R0

16 Aug 2019Date Received





high.


COMMENTS

Louise Hope


Mary Ann Ola-A


Sanaa Hussain

Chemist

SIGNATORIES


ABN 44 000 964 278


PO Box 32


Welshpool WA 6983

Australia

Australia

t +61 8 9373 3500

f +61 8 9373 3556

www.sgs.com.au




PE137221.001

Water

12/8/19 8:30

19AVWP001

PE137221.002

Water

5/8/19 13:00

19AVWP002

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name


pH** pH Units 0.1 7.0 7.0









Sulfate, SO4 mg/L 1 16000 17000






Potassium, K mg/L 0.1 2100 2300

Sodium, Na mg/L 0.5 41000 41000



PE137221.001

Water

12/8/19 8:30

19AVWP001

PE137221.002

Water

5/8/19 13:00

19AVWP002

Parameter LORUnits

Sample Number

Sample Matrix

Sample Date

Sample Name










MB DUP %RPD LCS

%Recovery




Total Alkalinity as CaCO3 LB162929 mg/L 5 <5 1 - 2% 99 - 101%


Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery



Reference


MB DUP %RPD LCS

%Recovery



Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery

Calcium, Ca LB162965 mg/L 0.2 <0.2 0 - 1% 95% 88%



Sodium, Na LB162965 mg/L 0.5 <0.5 1% 97% 95%


Reference


MB DUP %RPD LCS

%Recovery

pH** LB162934 pH Units 0.1 5.7 0% 101%


Reference








MB DUP %RPD LCS

%Recovery

MS

%Recovery

Sulfate, SO4 LB163084 mg/L 1 <1 0 - 7% 102 - 103% 100 - 102%


Reference


MB DUP %RPD LCS

%Recovery

MS

%Recovery

MSD %RPD



Reference


PE137221 R0


METHOD SUMMARY




AN101






2510 B.

AN106



AN106




AN113



AN113




AN135




AN274




AN275





AN320




AN320



Calculation


PE137221 R0


















11929.









IS

LNR

*

**






FOOTNOTES

LOR

↑↓

QFH

QFL

-

NVL

Limit of Reporting





Not Validated


APPENDIX E

NUMERICAL GROUNDWATER MODELLING

Appendix E Page 1

APPENDIX E - GROUNDWATER MODELLING

E1 Introduction

The objective of the groundwater modelling was to predict:

Groundwater inflows associated with the development of four open pits,

The potential for Managed Aquifer Recharge (MAR) to be used to dispose of water in excess

of the project water demand. Water requirements for the project have been estimated as:

o 0.67 GL per annum for roads (~1,835 kL/d),

o 0.16 GL per annum for mining during the wet season (~440 kL/d),

o 0.31 GL per annum for mining during the dry season (850 kL/d),

o Total water demand is estimated to vary between ~2,300 and 2,700 kL/d.

The regional water level change associated with dewatering,

The long term behaviour of the mined out pit voids.

The model was calibrated to available data and used to predict:

Groundwater inflows to the four proposed open pits over the life of the mine.

The regional drawdown and catchment water balance impact of pit dewatering over the life

of the mine.

The potential for the lower aquifer of the Lake Annean paleochannel, located south of the

open pits, to be used to manage dewatering abstraction, in excess of the project water

demand, via MAR, and any associated water level changes.

The long term behaviour of the final pit voids once mining is complete, including the time

taken for recovery to post mining or equilibrium level and the time taken for recovery.

Key features of the groundwater model are described in detail in the following sections and

summarised below. The model includes:

The upper (shallow mixed aquifer) and lower (deep) paleochannel aquifers of the Lake

Annean paleochannel, separated by a confining clay.

A similar sequence of aquifers and aquitards in tributaries of the Lake Annean paleochannel.

The mine area, including the orebody aquifer and adjacent fault.

Rainfall recharge to the aquifer system.

Groundwater inflow from upstream, from the northwest, southwest and southeast.

Groundwater outflow to the northwest.

E2 Model Set Up and Extent

The model was developed using the Modflow SURFACT groundwater modelling code (Hydrogeologic,

1996) operating under the Groundwater Vistas graphical user interface. The model was calibrated to

steady state conditions, with transient simulations used to predict dewatering of open pits and mine

closure impacts.

The extent of the model domain and the location of model boundaries are shown in Figure E1 and

summarised in Table E1. The model and all associated data are specified using the GDA 94 (Zone 50)

coordinate system. The model grid is rotated 30 degrees to align it with the inferred groundwater

flow direction. The model domain covers an area of 39 km north west to south east and 41 km

northeast to southwest.

Appendix E Page 2

Table E1: Extent of Model Domain

Easting (m)* Northing (m)*

Northwest 660,385 7,042,975

Northeast 694,080 7,023,530

Southwest 638,500 7,005,025

Southeast 672,260 6,985,520

A minimum model cell size of 50 m is assigned in the mine area (refer Figure E1) to accommodate

the geometry of the pits and the paleochannel aquifers. A maximum cell size of 650 m is assigned

elsewhere away from the mine and paleochannel areas. The model includes 408 rows and 413

columns over seven model layers resulting in a total of 1,179,528 model cells and 1,157,233 active

model cells.

E3 Model Geometry

Seven model layers are used to represent the mine area and the lower aquifer, clay aquitard and

upper aquifer of the Lake Annean paleochannel and tributaries. Low hydraulic conductivity basement

is represented by model layer seven, as well as the areas outside the paleochannel aquifer. Model

layers are generally assigned a uniform thickness with model geometry summarised in Table E2.

Aquifer property zones for model layers 1 to 6 are shown in Figures E2, E3 and E4 (model layer 7 is

included as basement only). The orebody is simulated over a length of 14 km and assigned a width

of 0.3 km. In the Lake Annean paleochannels the upper aquifer, aquitard and lower aquifer are

assigned widths of 1 to 2 km, 0.7 to 1.8 km and 0.5 to 1.2 km respectively.

A schematic model section is shown in Figure E5.

Table E2: Summary of Model Geometry

Layer Aquifer Units Layer Geometry

1 Basement, orebody and fault and shallow (upper) mixed aquifer

Top of layer represents ground surface (from SRTM). Base of layer set to simulate a minimum saturated thickness of 10 m in the paleochannel area (15 m total thickness). In areas of higher elevation, layer thickness increases to a maximum of 130 m. In areas of lower elevation, thickness reduces to a minimum of 15 m.

2 Basement, orebody and fault and paleochannel shallow (upper) mixed aquifer

Layer thickness of 10 m across model domain.

3 Basement, orebody and fault and paleochannel clay aquitard Layer thickness of 40 m across model domain.

4 Basement, orebody and fault and paleochannel confining clay aquitard


5 Basement, lower orebody and fault and paleochannel deep (lower) aquifer


6 Basement, lower orebody and fault

Layer thickness of 80 m to 140 m across model domain, consistent with a base of layer elevation of 230 mRL.

7 Basement Layer thickness of 10 m across model domain.

Appendix E Page 3

E4 Groundwater Inflow and Outflow

E4.1 Groundwater Throughflow

The locations of all model boundaries are shown in Figure E1. The general direction of groundwater

flow in the model domain is as follows:

From areas of higher topographic elevation toward drainage lines and the Lake Annean

paleochannel, including from northeast to southwest, along tributaries to the Lake Annean

paleochannel.

From southeast to northwest along the Lake Annean paleochannel.

Groundwater inflow to the modelled catchment from upstream is simulated by using fixed head inflow

boundaries (shown in Figure E1). The north eastern upstream boundary is set at an elevation of

490 mRL and is aligned with the estimated 490 mRL groundwater elevation. The southwestern

boundary, to the south of the Lake Annean paleochannel is set at an elevation of 465 mRL (also

aligned with the estimated 465 mRL groundwater elevation). This boundary was chosen to allow

simulation of the impacts of dewatering and MAR in the palaoechannel aquifer and the basement

immediately south of paleochannel. The upstream and downstream ends of the Lake Annean

paleochannel are set at elevations of 466 mRL and 440 mRL respectively to simulate groundwater

inflow from upstream and outflow to downstream. In each model layer, the extents of the fixed head

boundaries associated with the Lake Annean paleochannel are limited to the extent of aquifer where

it crosses the boundary (i.e., consistent with the aquifer distributions discussed in Section E3 and

shown in Figures E2 to E4). Fixed head boundaries are assigned in all six model layers.

All other model boundaries are aligned perpendicular to the inferred groundwater flow direction and

are set as no flow boundaries, as shown in Figure E1. These boundaries are set far enough away to

have minimal impact on model predictions.

E4.2 Recharge

In addition to groundwater inflows from upstream, the groundwater system is also recharged by

incident rainfall. In this arid environment, where evaporation exceeds long term rainfall by a factor

of almost 10, rainfall recharge to groundwater is expected to be low. Recharge to groundwater is

assumed to be along aquifers and drainage lines with recharge also assigned to the basement.

E4.3 Dewatering

Groundwater inflows into the open pits were simulated using the Drain (DRN) package in Modflow

SURFACT. The DRN package uses a head dependent relationship to predict the groundwater flow

that would result in a reduction in water level to a specified elevation. Drain cell elevations can

change in time and extent over the duration of a model prediction. Dewatering was simulated during

model predictions only.

E5 Model Calibration

Model calibration is the process by which the parameters of a numerical model are adjusted, within

realistic limits to provide the best match to measured data. This process involves testing and refining

the aquifer properties and the boundary conditions of the model to improve the match between

observed data and simulated values. The current model calibration used a manual or trial and error

approach. The amount of available data, in particular water level monitoring across the modelled

catchment and the applicability to a long term or steady state water level calibration means that

Appendix E Page 4

using automated techniques to calibrate the model will not increase the reliability of model

predictions.

An initial steady state model was completed to generate a set of initial or pre-development

groundwater levels that reflect groundwater conditions period to the start of pumping. The

groundwater level data available for model calibration was provided from the following sources:

Groundwater monitoring from the Department of Water and Environmental Regulation

(DWER) data base.

Monitoring from 13 bores installed during the recent hydrogeological investigations, located

on the orebody and in the paleochannel aquifer.

Ideally all water level data used for steady state model calibration would be contemporaneous or

taken over the duration an investigation programme. The investigations to date were focused on

the orebody area and the paleochannel aquifers. The regional DWER monitoring was added to the

water levels from the hydrogeological investigations to allow water levels to be estimated across the

modelled catchment and allow assignment of appropriate boundary conditions. This data has been

used as part of the calibration, however, there are uncertainties associated with this data (bore

construction details, water levels impacted by pumping / discharge etc.).

No historical or long term groundwater monitoring data from across the modelled catchment is

available to calibrate the model to time varying or transient conditions.

E5.1 Steady State Calibration

The locations of bores used for calibration of the steady state model are shown in Figure E6. Measured

groundwater levels and contours of predicted groundwater levels (steady state conditions) are shown

in Figure E7. The contours of predicted water levels show the general direction of groundwater flow

across the model domain.

Measured and modelled water levels are presented in Figure E8 and summarised in Table E3. In

general, measured groundwater levels at investigation bores are well matched with the difference

between measured and modelled water levels between 1 and 2 m. The maximum difference between

measured and modelled water levels in recently installed bores is 4.8 m. This difference is at bore

19AVWP001, which is located in the mine area. This bore is also close to bore 19AVWM105, where

the difference between measured and modelled water levels is 1.4 m.

Appendix E Page 5

Table E3: Measured and Modelled Water Levels

Bore Name Hydrogeological Unit Measured Water Level

Modelled Water Level

Difference (m)*

19AVWM01 Paleochannel (deep) 454.61 454.75 ‐0.14

19AVWM02d Paleochannel (deep) 452.21 452.82 ‐0.61 19AVWM02s Paleochannel (shallow) 456.12 455.83 0.29

19AVWM03 Paleochannel (shallow) 454.83 450.99 3.84

19AVWM04 Paleochannel (shallow) 456.34 457.58 ‐1.24

19AVWP002 Paleochannel (shallow) 456.26 457.5822 ‐1.32 19AVWM108 Orebody 458.46 458.81 ‐0.35

19AVWM104 Orebody 456.38 458.64 ‐2.26

19AVWM105 Orebody 457.33 458.75 ‐1.42

19AVWM112 Orebody 460.50 458.61 1.89

19AVWM113 Orebody 461.07 459.14 1.93

19AVWM114 Orebody 457.60 458.50 ‐0.90

19AVWP001 Orebody 453.94 458.77 ‐4.83

Camel unknown 483.03 476.14 6.88

Fig unknown 490.57 486.40 4.17

Hopout unknown 486.92 482.45 4.47

Sunday unknown 480.84 480.01 0.83

Bullock unknown 491.32 483.97 7.35

Centre unknown 484.86 487.93 ‐3.08

Well unknown 479.68 473.25 6.43

No358NallineWell unknown 470.01 465.28 4.74

No360ReidWell unknown 472.69 467.07 5.61

No339Newwell unknown 473.96 459.40 14.56

ScourWell unknown 462.51 463.90 ‐1.39

No333Well unknown 462.88 462.12 0.77

No335Peggy unknown 462.45 462.52 ‐0.06

No338MogulWell unknown 463.02 464.05 ‐1.04

2576FootPaddock unknown 474.25 484.92 ‐10.67

267HorseWell unknown 477.91 484.88 ‐6.97

241Well unknown 472.22 476.40 ‐4.18

244New unknown 472.12 474.52 ‐2.40

250WestWell unknown 486.29 485.07 1.22

‘* Positive number denotes under prediction of water levels. Negative number denotes under

prediction of water level.

At DWER data base bores, there are greater differences between measured and modelled water

levels. These water levels were not recorded contemporaneously, and it is unknown if they are

impacted by pumping from these locations. At these locations, measured and modelled water level

are generally consistent however, greater differences between measured and modelled water levels

are predicted when compared to the hydrogeological investigation bores.

Appendix E Page 6

The Scaled Root Mean Squared (RMS) error as a range of the measured range of water level is

calculated to be 10% when the outlying water levels (from the DWER data base) are discounted. The

mean absolute error is 2.75 m. No weighting has been used in these calculations.

As part of model calibration, the amount of recharge applied to the steady state model was adjusted

to match regional groundwater levels. Uniform recharge of 5.8 x 10-8 m/d is assigned to the upper

paleochannel aquifers and the surrounding basement. Recharge rates have not been widely studied

in this area and are difficult to quantify (Johnson and Commander, 2006). This modelled recharge

value is however consistent with long term estimates of groundwater recharge in arid areas of

Western Australia (e.g., Commander et al, 1992) of around 0.01% of average rainfall.

The model predicted steady state water balance is presented in Table E4.

Table E4: Model Predicted Steady State Water Balance

Water Balance Component In (kL/d) Out (kL/d)

Inflow From Upstream 750 -

Outflow To Downstream - 820

North Catchment Inflow (Including Paleochannel) 385 -

South Catchment Inflow 140 -

East flow through Paleochannel 210 0

West flow through Paleochannel 0 810

Recharge 75 -

Total 810 810

E5.2 Aquifer Parameters

Aquifer parameters assigned to the calibrated steady state model are summarised in Table E5. The

modelled aquifer parameter distributions are shown in Figures E2 to E4. Aquifer storage parameters

are not calibrated and are assigned consistent with measured data and similar hydrogeological

environments.

Appendix E Page 7

Table E5: Calibrated Aquifer Parameters

Aquifer unit Layer Horizontal Hydraulic

Conductivity (m/d)

Vertical Hydraulic

Conductivity (m/d)

Specific Yield (%) Storage

Shallow Mixed Aquifer Lake Annean Paleochannel 1 20 2 7.5 NA*

Shallow Mixed Aquifer Paleochannel Tributaries 1 1 - 5 0.1 to 0.5 7.5 NA*

Basement 1 0.1 0.01 1.0 NA*

Orebody 1 1.0 0.1 2 NA*

Fault 1 to 6 0.1 0.1 0.01 0.00005***

Shallow Mixed Aquifer Lake Annean Paleochannel 2 10 1 7.5 0.00005

Shallow Mixed Aquifer Paleochannel Tributaries 2 1 - 5 0.1 to 0.5 7.5 0.00005

Basement 2 0.05 0.005 0.1 0.00001

Orebody 2 0.01 0.001 2 0.00005

Confining Clay Lake Annean Paleochannel and Tributaries 3 & 4 0.001 0.00001 6 0.00005

Basement 3 0.05 0.005 0.1 0.00001

Orebody 3 & 4 0.005 0.0005 1 0.00005

Basement 4 0.005 0.0005 0.1 0.00001

Deep Aquifer Lake Annean Paleochannel and Tributaries

5 10 1.0 15 0.00005

Basement 5 to 7 0.0001 0.0001 0.05 0.00001

Orebody 5 & 6 0.005 0.00005 0.1 0.00005

* Modelled aquifers are assumed to be unconfined in the upper most model layer (layer 1) ** Confined storage coefficient specified in layers 2 to 6 only as the fault is modelled as an unconfined aquifer in model layer 1

E5.3 Other Model Details

Other details of model set up are outlined below:

Transient modelling for dewatering and closure used annual stress periods (periods over

which all stresses are held constant).

o The Modflow SURFACT Automatic Time Stepping (ATO) package was used for all

transient (time varying) simulations with the following parameters:

o An initial time step length of 30 days was used.

o A minimum time step of 1x10-10 days and a maximum time step length of 90 days

o A multiplier factor of 1.2 and a reduction factor of 2.0.

These parameters result in a maximum time step length of up to 90 days.

The model was also run with the Modflow SURFACT Block Centred Flow 4 (BCF4) package

using the Variably Saturated Flow Option (Pseudo Soil Relations).

Appendix E Page 8

The model was run with the Pre-Conjugated 5 (PCG5) solver along with the following

parameters:

o Number of outer iterations - 100

o Number of inner iterations - 20

o Maximum orthoganalisations - 10

o Head change criteria = 0.01 m

o Relative convergence criterion = 0.1

o Newton Raphson Linearisation (Back tracking Factor) = 0.9

o Newton Raphson Linearisation (Residual Reduction Factor) = 1

E6 Model Predictions

The calibrated model was used to:

Predict groundwater inflows to the open pits to allow calculation of water disposal

requirements in excess of the project water demand which has been estimated at between

2,300 kL/d and 2,700 kL/d (for the wet and dry seasons respectively).

Predict the water level (drawdown) impact of open pit dewatering at the end of mine life.

Predict the potential for MAR to the lower paleochannel aquifer to be used to dispose of

dewatering in excess of the project demand.

Predict the recovery of water levels in mine out pits once mine in complete, assuming that

pits are left empty, including final equilibrium levels and the time taken for recovery to final

levels.

These predictions were completed assuming transient conditions.

E6.1 Prediction Set up

For single open pit developments, in low permeability basement rock environments with limited

hydrogeological data, groundwater inflows to open pits and the long term behaviour of final mine

voids can be estimated using analytical methods. This analytical approach can be just as reliable as

numerical approaches in some environments (single pits developed in low permeability

environments). The current plan for the project includes four open pits, with basement rocks to the

north and a paleochannel to the south. To simulate the groundwater interactions between the

adjacent pits / pit voids, and the variable aquifer conditions close to the pits, a numerical approach

is required.

Prediction of groundwater inflow to the open pits was completed for the mine plan provided, in dxf

format. The plan included 40 pit progressions for four pits for a period of 25 years. Mine plans were

provided in quarterly increments for Year 1 to 5 in 0624_avl_v6_1_y1_q1_surf_mga.dxf to

0624_avl_v6_1_y5_q4_surf_mga.dxf and annual increments for Years 6 to 25 in

0624_avl_v6_1_y6_surf_mga.dxf to 0624_avl_v6_1_y25_surf_mga.dxf. Mining will progress to a

depth of between 110 m and 240 m below ground surface and will cover a total mined area of up to

260 ha. The extent of the mining area with Pit Locations is shown in Figure E8.

Other details of model predictions are outlined below:

Operational (mining) model predictions were completed for the period Year 1 to Year 25,

using an annual time increment or stress period, with initial water level conditions for model

predictions taken from the steady state model calibration.

Appendix E Page 9

The dewatering approach, uses the DRN package in Modflow Surfact, Drain elevations and

extents were set consistent with the mining schedule provided. The mining schedule used is

summarised in Table E6.

As the DRN package is used to simulate water level reduction consistent with the mine plan,

no advanced dewatering is predicted ahead of mining.

All other groundwater inflows and outflows in the catchment are assigned consistent with

the steady state calibration.

Aquifer parameters are not changed during model predictions as any enhanced aquifer

potential that develops in the pit area (due to blasting or hydromechanical processes) will

be small in scale and will not impact the regional groundwater flow system.

No other groundwater development (dewatering of open pits, water supply pumping, MAR,

seepage from Tailings Storage Facilities (TSFS) or stock water use) is included in model

predictions.

The results of the dewatering prediction were used to calculate water disposal requirements.

Table E6: Mining Schedule Used for Dewatering Predictions

Year Deepest Mining Elevation (mRL)

Pit 1 Pit 2 Pit 3 Pit 4 1 420 400 - - 2 410 380 - - 3 380 380 450 - 4 350 380 430 - 5 350 360 400 - 6 350 340 370 - 7 350 320 370 - 8 350 320 370 - 9 350 320 370 - 10 350 310 370 - 11 350 350 460 12 330 340 460 13 330 320 460 14 330 310 460 15 330 290 450 16 330 290 430 17 330 290 420 18 330 290 410 19 330 280 380 20 330 270 360 21 330 260 - 22 330 240 - 23 330 230 - 24 300 230 - 25 300 230 -

Appendix E Page 10

E6.2 Mine Closure

Closure predictions have been completed assuming the mine voids will be left empty after closure.

Post mining (closure) predictions were completed for a period of 100 years to simulate the balance

between rainfall recharge, groundwater inflows and evaporation from the pit void lake surfaces and

the impact on regional water levels as depleted storage is replenished by rainfall recharge and

groundwater inflows. Analytical estimates of groundwater recovery suggest that a significant pit lake

will not develop in the final pit void and water will only be present intermittently in the lower benches

of the pit void. This is because the evaporation from the empty pits is estimated to be higher than

the long-term inflows (groundwater inflows and recharge).

Closure predictions have been completed for a Base Case that includes the conditions outlined below

and a Recharge Case, which also includes recharge the from surface water flows in creeks located to

the south of the mine and between Pits 2 and 4. Recharge of 5 mm is included biennially over a

period of a month. Other details of the closure predictions are summarised below:

Initial water level conditions for the closure predictions were taken from the end of the

dewatering prediction.

The open pits are left empty after the end of mining (i.e. no backfilling).

The final mine areas are bunded so that the final pit catchment is similar to the final pit crest

areas.

Groundwater recovery in the open pit is assumed to commence immediately after the end

of mining (i.e. after 25 years of mining).

The geometry of the mined-out pit is included in the model by assigning pit void cells a high

hydraulic conductivity value (99 m/d) and specific yield value (99%). This approach

simulates the mined-out pit as a lake surrounded by undisturbed material.

Once a pit void lake is predicted to develop, it is subject to evaporation equivalent to 75%

of average annual pan evaporation of 1,950 mm/year. This is based on annual average pan

evaporation for Meekatharra of 2,600 mm per year (Luke, 1987).

Recharge to the mine voids is assigned as follows:

o Recharge to the pit lake is assigned at 100% of long term average annual rainfall

(238 mm/year).

o Runoff from the area between the pit void lake and the pit crest also recharges the

pit void lake. This runoff is included at a rate of 20% of annual average rainfall that

falls on the area between the pit void lake and the pit crest.

E7 Prediction Results

E7.1 Dewatering Predictions

Predicted groundwater inflows for each year of mining are shown in Figure E10. The maximum

predicted dewatering rate is 8,000 kL/day in the first year of mining, decreasing to 1,300 kL/day by

Year 25. The average groundwater inflow over the life of mine is 2,660 kL/day.

Predicted water levels for selected locations in the mining areas (Pits 1 to 4) are shown in Figures

E11 and E12. Contours of predicted water level drawdown after 25 years of dewatering are shown in

Figure E13. The predicted drawdown is the difference between pre-mining water levels and the water

levels predicted at the end of mining (Year 25 of mine life). The following observations are made

regarding the predicted drawdown:

Appendix E Page 11

Maximum drawdown is predicted in Pit 3 (228 m).

Away from the mining areas drawdown of 1 m is predicted a maximum distance 8 km from

the south eastern end of the mining area (from Pit 1) and the north western end of the

mining area (from Pit 3) or 10 km from the centre of the mining area (from Pit 2).

Model predicted water balances at the end of mine life (Year 25) are presented in Table E7. The

predicted dewatering volumes have been drawn from aquifer storage and no changes to the

catchment and paleochannel inflows and outflows are predicted.

Table E7: Dewatering Water Balance

Water Budget Component In (kL/d) Out (kL/d)

Storage 2,805 0

Recharge 75 -

North Catchment Inflow (Including Paleochannel) 385 (385) -

South Catchment Inflow 140 (140) -

East flow through Paleochannel 210 (210) 0 (0)

West flow through Paleochannel 0 810 (810)

Recharge 75 (75) -

Pit Dewatering - 2,830

Total 3,640 (810) 3,640 (810)

Values in brackets are from the steady state model run

With the wet season or lower water demand of ~2,300 kL/d, disposal requirements are calculated at

up to 5,700kL/d over the life of mine (Figure E10). Assuming individual bore injection rates of

500 kL/day, a total of 12 bores located along the Lake Annean paleochannel south of the mine area

at a spacing of 1,000m were used to predict the potential to inject water to the lower paleochannel

aquifer. The rates of injection required, the limited extent of the lower aquifer and the shallow depth

to water predicted that injection under gravity was not feasible. Groundwater levels in the lower

aquifer were predicted to increase to at or above ground level along the Lake Annean paleochannel

and its tributaries within a year of commencement of re-injection. As a result, no further modelling

or optimisation of MAR was considered.

E7.2 Closure Predictions

Predicted water levels in the mine area during mining (25 years) and for the simulated closure period

100 years after the end of mining are shown in Figures E14 and E15. Post- mining water levels in

the mining areas are not predicted to recover due to the large evaporative area at the base of each

pit. The pits are predicted to develop into local sinks and pit lakes are predicted to develop in the

base of open pits and are discussed below:

Water levels in Pits 1, 3 and 4 are not predicted to recover and remain close to dewatered

levels of 300 mRL, 230 mRL and 360 mRL respectively or approximately 170 m, 240 m and

110 m below the pre- mining ground surface respectively (or 160, 230 and 100 m below the

pre-mining water table respectively). The pit lakes are predicted to be less than 1 m deep

and may intermittently dry up depending on the conditions that develop from episodic rainfall

/ run off which is not simulated in the prediction model.

Appendix E Page 12

Water levels in Pit 2 are predicted to recover to 332 mRL or approximately 140 m below the

pre-mining ground level (130 m below the pre-mining water table) 35 years after the

cessation of dewatering. The southern eastern edge of Pit 2 is located on the northern side

of a shallow tributary of the Lake Annean paleochannel and higher inflows to this pit are

possible once mining in complete compared to the other pits. The Pit 2 void lake is predicted

to be approximately 22 m deep. This pit void lake is predicted to persist during the year

with small fluctuations in response to episodic rainfall / run off.




Similar pit void lake responses are predicted for both closure simulations (Base Case and

Recharge Case).

Contours of predicted water level drawdown 100 years after the end of mining are shown in Figure

E16 for the Base Case and Figure E17 for the Recharge Case. The following observations are made

regarding the predicted drawdown after mine closure:

For both cases in the mine area, where pit lakes are predicted to develop, water levels are

between 100 m to 230 m below pre-mining water levels. Similar drawdown is predicted for

both cases.

For the Base Case drawdown of 1 m is predicted to extend a maximum distance of 13 km to

the north and 14 km to the south of the mine area (from the centre of Pit 2). Drawdown of 1 m is

also predicted to extend through the paleochannel aquifers a maximum distance of 15 km to the

south east of the centre of the mining area, and 18 km west.

For the Recharge Case, drawdown of 1 m is predicted to extend a similar distance to the

north as the Base Case (~13 km). Drawdown to the west along the paleochannel is

predicted to be reduced in extent compared to the Base Case (~3 km reduction). Similar

drawdown is predicted to the east and to the south. Closer to the mine area, there is also

some reduction in predicted drawdown along the paleochannel. These results suggest that

significant recharge from the creek systems would be required to mitigate the long term

drawdown that would result from long term groundwater discharge from pit void lakes.

The model predicted water balance 100 years after mine closure is shown in Table E8 for the Base

Case and in Table E9 for the Recharge Case. The water balance is shown for the January of the last

year of the simulation (i.e., when enhanced recharge is included in the Recharge Case model). The

groundwater sinks that are predicted to develop in the pit voids will continue to remove water from

the catchment into the future. As a result, groundwater inflows, from the north east and south, to

the catchment are predicted to increase as the impact of the pit voids extends to the model

boundaries. Correspondingly, groundwater outflow to the west is also predicted to decrease. The

difference in the model predicted water balances for the Base Case and the Recharge Case are small

and suggest that the recharge rates adopted have a minimal impact on the modelled catchment

water balances.

Appendix E Page 13

Table E8: Closure Water Balance Base Case


Storage 530 0

Recharge 75 (75) -

Recharge to Pit Voids 775 -

Northern Inflow (Including Paleochannel) 390 (385)

Southern Inflow 140 (140)

Eastern Inflow To Paleochannel 360 (210)

Western Outflow From Paleochannel 0 600 (810)

Evapotranspiration from Pit Voids - 1,670

Total 2,270 (810) 2,270 (810)

Table E9: Closure Water Balance Recharge Case


Storage 340 0

Recharge 460 (75) -

Recharge to Pit Voids 775 -

Northern Inflow (Including Paleochannel) 390 (385) -

Southern Inflow 145 (140) -

Eastern Inflow To Paleochannel 325 (210) -

Western Outflow From Paleochannel 0 765 (810)

Evapotranspiration from Pit Voids -

Total 2,435 (810) 2,435 (810)

E8 Model Limitations, Uncertainties and Class

The numerical groundwater flow model was developed consistent with the available data and includes

the results of hydrogeological investigations to date. The model replicates measured water levels and

flow directions in the immediate mine area and the inferred direction of groundwater flow in the

catchment is matched.

As with all models, there are limitations associated with data availability, conceptualisation and

representation of the hydrogeological process. The model includes known features of the system and

is calibrated to the available information.

The following is a list of modelling limitations included in the current model setup:

The model is setup to predict regional impacts (water level and catchment water balance

changes) of dewatering and mine closure. The model does not include detailed local scale

features (for example small faults and fractures in the immediate mine area or the

development of areas of enhanced permeability due to blasting or hydromechanical

processes). These features are unlikely to have an impact on the regional system and are

generally only important in the prediction of near pit conditions (for example when pore

pressures are predicted close to pit faces).

Appendix E Page 14

The model was calibrated to limited data in the pit area, the alluvial aquifer and regionally.

No long-term transient data exists for the immediate mine area or the paleochannel for both

natural and aquifer stress conditions. As a result, the assigned aquifer storage parameters

are not calibrated and are assigned consistent with similar hydrogeological environments.

A number of assumptions have been included in the model as outlined below:

Recharge to the final pit void will vary depending on the final pit catchments and run off

characteristics of the pit void and walls. The current closure scenario includes runoff from a

final pit catchment that extends 50 m from the pit crest to simulate the runoff that would

occur after mine closure from inside the limits of an abandonment bund at the completion

of mining.

Evaporation from the pit void lake is assigned at a rate of 75% of average annual

evaporation. This value may be more, or less, depending on in-pit conditions however, it is

likely that the pits will develop into long term sinks over a wide range of assigned evaporation

rates due the water deficit of the area.

Long term predictions do not account for potential climate change and the subsequent impact

on evaporation and rainfall conditions of the future.

The groundwater model developed for the mining and surrounding groundwater catchment was

completed consistent with the Australian Groundwater Modelling Guidelines (Barnett et al, 2012).

Based on the Australian Groundwater modelling guidelines (2012), specifically Table 2:1 (Model

confidence level classification – characteristics and indicators), the model satisfies the requirements

of a Class 1 confidence level (the lowest level) as:

The model is not calibrated to long term data and the model is not calibrated to aquifer

storage.

The duration of model predictions (25 year of dewatering and 100 year of recovery) is not

replicated by the model calibration.

Aquifer stresses from dewatering, injection and closure are also not replicated in the model

calibration.

Table 2.1 of the modelling guidelines suggests that the model is suitable to predict the impacts of

the proposed development, which is low risk, in a low value aquifer (hypersaline environment with

no other significant groundwater users). The guidelines also suggest that the model is suitable for

the prediction of dewatering rates at this level of study.

E9 References

Barnett et al, 2012, Australian groundwater modelling guidelines, Waterlines report, National Water

Commission, Canberra.

Commander, D. P., Kern, R. M. and Smith, R. A. 1992, Hydrogeology of the Tertiary Palaeochannels

in the Kalgoorlie Region (Roe Palaeodrainage), Geological Survey of Western Australia, Record

1991/10.

Environmental Solutions, Inc. 1996-2011. Groundwater Vistas Version 8.06 Build 18.

Hydrogeologic Inc (1996). MODHMS / MODFLOW-SURFACT. A Comprehensive MODFLOW-Based

Hydrologic Modelling System.

Appendix E Page 15

Johnson, S.L., and Commander, D.P., 2006. Mid West Regional Minerals Study – Groundwater

Resource Appraisal, Department of Water, Hydrogeological Record Series HG 17.

Luke, G J, Burke, K L, and O'Brien, T M. (1987), Evaporation data for Western Australia. Department

of Agriculture and Food, Western Australia, Perth. Report 65.

\\dc02\Jobs\183\4.GIS\Workspaces\Figures\048 Figures\Appendix E - Modelling\Figure E2 - Aquifer PropertiesLayer 1 and 2.qgz

Project

Location Map

Notes and Data Sources:

Coordinates: MGA Zone 50

JOB No: 183

REPORT No: 048b

DATE: 29/10/2020

DRAWN: GC

AUTHOR: KLR Aquifer Properties forLayers 1 and 2

Figure E2:

Shallow Mixed Aquifer



Basement

Orebody

Fault

Orebody

Basement

Paleochannel Upper Aquifer

Aquifer Zone

Fault

Ore Body


Project

Location Map



JOB No: 183

REPORT No: 048b

DATE: 29/10/2020

DRAWN: GC


Figure E3:

Confining Clay

Ore Body

Fault

Basement

Basement

Aquifer Zone

Fault

Ore Body


Project

Location Map



JOB No: 183

REPORT No: 048b

DATE: 29/10/2020

DRAWN: GC


Figure E4:

Deep Aquifer Fault Lower Orebody Basement Lower Orebody Basement

Aquifer Zone

Fault

Ore Body

South-West

Conceptual Schematic Model Section FIGURE E5\\dc02\Jobs\183\3.C&R\048 Figs & App\Appendix E_Modelling\[Figure E5 - Schematic Model Section.xlsx]Figure E5 - Section

Conceptual Diagram - not to scale

Section Approximate North East to South West

North-East

Measured and Modelled water levels FIGURE E8\\dc02\Jobs\183\3.C&R\048 Figs & App\Appendix E_Modelling\[Figure E8 - RMS plot.xlsx]Figure E7

19AVWM01

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Mining stops after 25 years


Closure Period of 100 years


Modelled Water Levels for Pits 3 and 4 During Closure FIGURE E15\\dc02\Jobs\183\3.C&R\048 Figs & App\Appendix E_Modelling\[Figure E14 and 15 - Predicted Water Levels for Closure.xlsx]Figure E15

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