=E) Homestake Mining Company of California HO _I__AE Jesse R. Toepfer Grants Project ClosureManager 20 November 2014 ATTN Mr. David L. Mayerson Mining Environmental Compliance Section Ground Water Quality Bureau New Mexico Environment Department P.O. Box 5469 Santa Fe, New Mexico 87502-5469 RE: Homestake's Responses to NMED's Comments Received 22 September 2014 Pertaining to Homestake's TPP Alluvial Pilot Testing Summary Report dated 3 July 2014 Mr. Mayerson: Homestake Mining Company of California (HMC) received from the New Mexico Environment Department (NMED) comments in a letter dated 22 September 2014, entitled Homestake Mining Company of California millsite/DP-200 - Comments from NMED's review of "Responses to NMED comments regarding Homestake's November 2013 'Update on treatment activities"' (August 21, 2014) and "TPP [Tripolyphosphate] alluvial pilot testing summary report" (July 3, 204). Enclosed with this letter you will find HMC's responses to NMED's comments in the aforementioned letter. NMED's 22 September letter and comments are also herein enclosed. On behalf of Homestake, I hope this information is helpful to your department and will be of value to you during the review process. Please feel free to contact me directly at 505.290.3067 if you have any questions or comments pertaining to this material. Respectfully, Jesse R. Toepfer Closure Manager HOMESTAKE MINING COMPANY OF CALIFORNIA Copy To: Mr. Jack Parrott, US Nuclear Regulatory Commission - Rockville, Maryland Mr. Sai Appaji, US Environmental Protection Agency, Region 6 - Dallas, Texas Mr. Wayne Canon, New Mexico Office of the State Engineer - Albuquerque, New Mexico Ms. Deborah Barr, US Department of Energy, Office of Legacy Management - Grand Junction, Colorado Mr. David Shafer, US Department of Energy, Office of Legacy Management - Westminster, Colorado Mr. Bill Ferdinand, Barrick Gold - Salt Lake City, Utah Mr. Patrick Malone, Barrick Gold - Salt Lake City, Utah Mr. George Hoffman, Hydro Engineering - Casper, Wyoming Mr. Phil DeDycker, ARCADIS U.S., Inc. - Denver, Colorado hMs Homestake Mining Company P.O. Box 98, Grants, NM 87020 Tele: (505) 287-4456 Fax: (505) 287-9289
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=E) Homestake Mining Company of CaliforniaHO _I__AE Jesse R. Toepfer
Grants Project Closure Manager
20 November 2014
ATTN Mr. David L. MayersonMining Environmental Compliance SectionGround Water Quality BureauNew Mexico Environment DepartmentP.O. Box 5469Santa Fe, New Mexico 87502-5469
RE: Homestake's Responses to NMED's Comments Received 22 September 2014 Pertaining toHomestake's TPP Alluvial Pilot Testing Summary Report dated 3 July 2014
Mr. Mayerson:
Homestake Mining Company of California (HMC) received from the New Mexico Environment Department(NMED) comments in a letter dated 22 September 2014, entitled Homestake Mining Company ofCalifornia millsite/DP-200 - Comments from NMED's review of "Responses to NMED commentsregarding Homestake's November 2013 'Update on treatment activities"' (August 21, 2014) and "TPP[Tripolyphosphate] alluvial pilot testing summary report" (July 3, 204).
Enclosed with this letter you will find HMC's responses to NMED's comments in the aforementioned letter.NMED's 22 September letter and comments are also herein enclosed.
On behalf of Homestake, I hope this information is helpful to your department and will be of value to youduring the review process. Please feel free to contact me directly at 505.290.3067 if you have anyquestions or comments pertaining to this material.
Respectfully,
Jesse R. ToepferClosure ManagerHOMESTAKE MINING COMPANY OF CALIFORNIA
Copy To:
Mr. Jack Parrott, US Nuclear Regulatory Commission - Rockville, MarylandMr. Sai Appaji, US Environmental Protection Agency, Region 6 - Dallas, TexasMr. Wayne Canon, New Mexico Office of the State Engineer - Albuquerque, New MexicoMs. Deborah Barr, US Department of Energy, Office of Legacy Management - Grand Junction, ColoradoMr. David Shafer, US Department of Energy, Office of Legacy Management - Westminster, ColoradoMr. Bill Ferdinand, Barrick Gold - Salt Lake City, UtahMr. Patrick Malone, Barrick Gold - Salt Lake City, UtahMr. George Hoffman, Hydro Engineering - Casper, WyomingMr. Phil DeDycker, ARCADIS U.S., Inc. - Denver, Colorado
"Responses to NMED comments regarding Homestake's November 2013 'Update on treatment activities"' (August 21, 2014)
1 Comment This difference in Another important consideration for the This is correct; TPP reacts with water (hydrolysis) to formI retardation and achievable development of a "barrier" also should include orthophosphate (the form of phosphorus that reacts with
distribution is an important amount and rate of orthophosphate formation to uranium (and calcium) to form low-solubility uranium-consideration for continued precipitate sufficient uranium to achieve the phosphate minerals (and calcium phosphate (apatite)). Theapplication of the uranium concentration standard considering hydrolysis reaction occurs over a period of days, aftertechnology-the design ... of a continued influx of background uranium injection the TPP is transported downgradient and reacts (andtransect of injection points concentrations. sorbs) along the groundwater flow-path. One way to ensureto create a "barrier" will that a discrete barrier is emplaced is to inject and extractensure complete lateral groundwater, recirculating the TPP across a targeted treatmentdistribution between the zone. This approach will be evaluated in the next phase of thepoints. alluvial pilot testing.
2 Comment The uranium-phosphate On page 20 of the Report, HMC stated that it Low-solubility uranium minerals have been documented to2 precipitates that form during was unable to directly identify the uranium and form in laboratory testing performed by the US Department of
TPP injection have very low calcium phosphate mineral phases during soil Energy (DOE) at Pacific Northwest National Laboratorysolubility under ambient coring and analysis. Therefore, please explain (PNNL); Dawn Wellman (cited in the quoted text) is one ofaquifer conditions (Wellman the basis for this statement. the lead researchers for this work.et al., 2005).
Since the mineral phases could not be identified Although these minerals were not directly identified in soilin this test phase, please explain how HMC can coring, this does not mean that they did not form, but rather isassure the long-term efficacy of any proposed due to the difficulty in sampling and recovery of soilbarrier containing these minerals. Uranium treatment efficacy is the
best means of demonstrating that these phases have formed.
"TPP alluvial pilot testing summary report" (July 3, 2ý014)
3 6 These uranium minerals As previously noted, HMC has stated that the Attachment 1 to this comment response letter includes ahave very low solubility mineral phases that are presumed to have formed stability diagram for uranium phosphate minerals as providedunder ambient aquifer could not be identified during analysis. in Jerden et al., 2003. Note that variations in ambientconditions... temperature and pressure will not significantly affect the
Please present stability diagrams from stability fields for the various forms of uranium shown in theauthoritative geochemical references to illustrate diagram. The most important factors that affect uraniumthis stability under varying conditions of Eh, pH, phosphate mineral stability are pH and phosphatetemperature and pressure that would be expected concentration.in the natural environment.
Homestake Mining Company of California2
Responses to NMED Comments Received Regarding the TPP Alluvial Pilot Testing Summary Report 20 November 2014
Comment Page # Quoted Text NMED Comment ResponseNumber
4 7-10 Not applicable Evaluation of tracer breakthrough and washout The local gradient within the S Area is dominated by theshould have included characterization of the hydraulic barrier; the closest reversal well to the S Area is welllocal ground water gradients within each test SO, and the closest re-injection well is WRI 8. Groundwaterplot prior to the inception of tracer injection, flow in the S Area is generally to the southwest. In the X Area,
the hydraulic gradient is relatively flat, with groundwater flowalso to the southwest.
5 11 Water from nearby Please address to what degree the use of water Use of water with uranium concentrations in excess of theextraction wells.. .was with uranium concentrations in excess of the alluvial site standard did not, and will not, adversely affectutilized to mix the injection alluvial aquifer site standard as injectate may process effectiveness. This water was amended with TPP andsolution. Measured uranium adversely impact process effectiveness. CaCI2 reagents and then injected into the ground; treatmentconcentrations in the occurred in the ground and the amendment was adequate toinjectate solution.. .are treat uranium in the extracted water and groundwater. Thiswithin the range observed in approach will be used for the next phase of the pilot test,other wells proximal to the where water will be extracted, amended, and then re-injected.pilot test areas...
6 12 Following the injections [in Please explain how the quantities of post- The quantities of water used to "flush" the injection well tothe S area], 1,200 gallons of injectate solution water were determined for minimize potential for fouling due to mineral precipitation atwater from S4 was injected each of the test plot areas. the well were based upon the volume of the well bore (belowto minimize precipitate the water table) as well as the sand pack and the amount ofbuild-up and potential Please explain if any difference in precipitate fluid that the aquifer could accept. In the S area, the largerfouling in the injection build-up and fouling was noted between the test volume was used due to the length of the screened-interval (15well.. .Following the plot areas S and X resulting from the different to 20 ft), and ease of fluid injection in this area, whereas in theinjections [in the X area] water sources that were used after injectate. X area, the smaller volume was used to the shorter screened-100 gallons of reverse interval (10 ft), smaller targeted treatment area, and lowerosmosis water was injected injectability.to minimize precipitatebuild-up and potential There was no difference noted in fouling or precipitate build-fouling in the injection well. up as the injection wells maintained their capacity to accept
injection fluids during the entire course of the pilot test.
Homestake Mining Company of California
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Responses to NMED Comments Received Regarding the TPP Alluvial Pilot Testing Summary Report 20 November 2014
Comment Page # Quoted Text NMED Comment ResponseNumber
7 14 Table 7 presents the targeted Data for achieved amendment concentrations at Table 7 provides the achieved concentrations of phosphorusand achieved amendment dose response wells are not included in this (total as phosphorus) and calcium in the injectate solution, asconcentrations for key table. Please clarify where these data can be well as the targeted in-solution concentrations of phosphorousinjection solution viewed, as well as the stated comparisons of in (as phosphate) and calcium.parameters (calcium and situ to targeted concentrations.phosphorus) for the injectate The in-situ targets for phosphorus (as phosphate) and calciumsolution and as measured at were both 1,000 mg/L. This corresponds to an in-situthe dose response wells... In phosphorous target (total as phosphorous) of 326 mg/L. Thethe S Area, in situ calcium achieved in-situ concentrations of phosphorus (reported asconcentrations were 6 to 9 total as phosphorous) are included in Table 4 (S Areatimes higher than targeted Performance Monitoring Data) and Table 5 (X Areaand TPP concentrations Performance Monitoring Data).were approximately half ofthe targetedconcentration.. .In the XArea, in situ calciumconcentrations wereapproximately half of thetargeted values (Table 7).However the injectateconcentration of TPP wasapproximately the same astargeted injectate values.
8 14 The difference between the The statement suggests that more accurate This is correct; target reagent strengths will be moreachieved in situ control of injectate reagents should be consistently achieved in future test work and at the full-scaleconcentrations of calcium implemented in order to achieve targeted dosage by carefully measuring reagents prior to batching.and phosphorus and the distribution more accurately.targeted concentrations ispartially due to batchingvariability.. .(likely due tocoarse measurement ofreagent masses [in theinjectate]).
Homestake Mining Company of California4
Responses to NMED Comments Received Regarding the TPP Alluvial Pilot Testing Summary Report 20 November 2014
Comment Page # Quoted Text NMED Comment ResponseNumber
9 15 This [significantly reduced This observation suggests that subsurface Subsurface stratigraphy exerts significant control on reagentdistribution of TPP in the X stratigraphic and structural variations (e.g., distribution for almost all injection-based treatment strategies.area] is consistent with the intercalated clay layers, fractures) might also There are several of ways to address this: 1) injection pointsfiner aquifer grain texture influence the distribution of reagents. Please with multiple screened intervals specifically targeting discreteobserved in the X Area. indicate how this could be addressed in a full- "injectable" zones of higher permeability, 2) use of both
scale implementation. injection and extraction wells for hydraulic control, and 3),more uniform delivery of reagent to the area targeted fortreatment. These strategies for addressing and overcomingstratigraphic control will be evaluated in the next phase of thealluvial pilot test.
10 15, Table Breakthrough of the Few pre-injection/baseline data for the cited Baseline data (TDS and chloride) are available for SDR-IS4, and injection solution [in S Area analytes are shown without explanation for wells and SDR-1D (see Table 4). These data are sufficient to
Appendix dose response and SDR-IS (no analytical data for TDS and evaluate increases in both parameters during injection.D monitoring wells] was also chloride), SDR-ID (I analysis each for TDS and
characterized by increased chloride; 2 for calcium). These data gaps make The molybdenum concentration at SDR-4S at 147 DPI is anconcentrations of TDS, difficult the evaluation of statements that follow, error; this should be 0.52 mg/L.chloride, calcium, total which compare post-breakthroughphosphorus, and concentrations to pre-injection/baseline Analytical data were collected for all constituents and areorthophosphate (Table 4). In concentrations. Please explain how the baseline included in Attachment 2 to this submittal.dose response wells SDR-1S data presented in this Report would be sufficientand SDR-ID, peak TDS and for this study in light of these observations.chloride concentrations wereapproximately 20 and 60 Please discuss the significance of the lasttimes higher than baseline recorded dissolved molybdenum concentrationvalues, respectively of 52 mg/L in well SDR-4S at 147 DPI, which is
two orders of magnitude greater than anyprevious analyses.
NMED notes that no analytical data are includedfor radium, thorium, sulfate, and nitrate in Table4, although data for sulfate concentrations areshown in the charts of Appendix D. All of theseconstituents have aquifer specific site standards.Possible impact of the TPP process onconcentrations of these constituents should beinvestigated and discussed in the pilot testingphase activities.
Homestake Mining Company of California5
Responses to NMED Comments Received Regarding the TPP Alluvial Pilot Testing Summary Report 20 November 2014
Comment Page # Quoted Text NMED Comment ResponseNumber
11 16 [Tracer] Washout was slow Please explain the significance, if any, of Tracer washout in the X Area was slower than the S Area duein [X area] dose response observed tracer washout rates with respect to to the lower groundwater flux and aquifer permeability in thiswells.., performance of the TPP process area. However, this slower washout does not negatively affect
performance of the TPP (a longer residence time for the TPPin the area influenced by the injected reagent is beneficial andallows for the treatment zone to be established as TPP ishydrolyzed to orthophosphate). The main challenge, however,with lower permeability is the difficulty in achieving a largedistribution of the injected reagent.
12 16, Table Breakthrough of the As for monitor wells in the S area (see Comment Baseline data are presented for one time period prior to5, and injection solution [within 10 above), few pre-injection/baseline data for injection (70 days pre-injection) for XDR-1, XDR-2, XDR-3
Appendix the X area dose response TDS and chloride are shown without explanation and XDR-4. Although this appears to be a limited data set, it isD wells] was also for wells XDR- 1, XDR-2, XDR-3 and XDR-4 (1 adequate to evaluate changes in TDS and chloride (the
characterized by increased analysis each). These data gaps make difficult changes were marked relative to baseline). In addition, theconcentrations of TDS, the evaluation of statements that follow, which baseline data are consistent with data available for monitoringchloride, and calcium... compare post-breakthrough concentrations to wells in this area that are routinely monitored and reported in
pre-injection/baseline concentrations. Please the annual groundwater monitoring report.explain how the baseline data presented in thisReport we be sufficient for this study in light of Analytical data were collected for all constituents are includedthese observations, in Attachment 2 to this submittal.
As stated previously, the pilot testing processshould include all analytes for which aquifer-specific site standards are established.
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0 0Responses to NMED Comments Received Regarding the TPP Alluvial Pilot Testing Summary Report 20 November 2014
Comment Page # Quoted Text NMED Comment ResponseNumber
13 17, Table At SMW-1, the uranium Although uranium concentrations did diminish SMW-I is outside of the direct influence of the TPP injection4, and concentrations decreased to 0.047 mg/L at 15 DPI as stated, NMED notes (outside of the radius of influence of the injection and beyond
Figure 8 from 1.44 mg/L to 0.047 that concentrations immediately rebounded to the dose response wells labeled with the prefix "SDR"). As themg/L (at 15 DPI). The high above the aquifer-specific site standard of 0.16 data show, even outside of the direct influence of the TPPuranium concentration mg/L by 21 DPI, and showed an increasing injection there was notable uranium treatment. The slightdetected at only one point trend through the remainder of data presented. increase in uranium concentrations is likely due to subtlepost-injection (at 20 DPI) in variations in groundwater flow direction (with groundwaterthis well is likely a The referenced high uranium concentrations of bypassing the emplaced treatment zone), as well as diminishedlaboratory error 1.56 is shown on Table 4 to occur at 15 DPI, ability of the phosphate to immobilize uranium. Although
not 20 DPI as stated herein. Please clarify this treatment longevity after just one injection was significant,discrepancy. treatment capacity diminishes over time with continual influx
of uranium into the treatment area. Continued sustainedtreatment capacity will be evaluated in the second phase of thealluvial pilot test.
The reference to the concentration of uranium (1.56 mg/L)
noted at 20 DPI is an error and this should be 15 DPI, asindicated correctly in Table 4.
14 17 Treatment trends at SMW- Please explain the significance of this SMW-3S and SMW-4S are further downgradient of the3S and SMW-4S are observation, injection well, even further than SMW-I (discussed above). Atsomewhat irregular; this greater distance downgradient, there is greater possibilityhowever, these wells are that subtle changes in flow direction that results indowngradient from the groundwater bypassing the injection wells will be noted asinjection wells.., concentration fluctuations at SMW-3S and SMW-4S.
The next phase of pilot testing will establish a larger,contiguous barrier such that changes in groundwater flowdirection will not result in perceived degradation in treatmentperformance.
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0Responses to NMED Comments Received Regarding the TPP Alluvial Pilot Testing Summary Report 20 November 2014
Comment Page # Quoted Text NMED Comment ResponseNumber
15 17, Table Uranium treatment remained NMED notes that uranium concentrations in It is important to note that the total volume of TPP injected4, and high after the injection SIW-D, SDR-IS, SMW-I and possibly SMW- into the injection wells in the S Area was limited (-6,700
Figure 8 solution had washed out... 4S appear to show rapid rebound from the lowest gallons injected into each well (shallow and deep injectionuranium concentrations achieved to end at wells), and the achieved radius of influence was approximatelyconcentrations near or above the aquifer-specific 10 feet. A treatment zone was established over a very limitedsite standard of 0.16 mg/L by the end of the data extent of the aquifer, purposefully at a small scale to evaluatepresented. Also, as HMC notes, baseline treatment efficacy. Even at this small scale, treatmenturanium concentrations in these wells ranged performance was good, and treatment was sustained for anfrom just above the referenced standard to extended period of time (out to 147 days post injection atapproximately one order of magnitude above the SDR-IS). This well (SDR-IS) is within the achieved radius ofstandard. Therefore it would appear that long- influence. The other wells are outside of the direct influence ofterm treatment efficacy was limited in this area. the injection, and as discussed above, slight increasing trends
at downgradient monitoring wells are likely due to changes ingroundwater flow direction and gradual loss of treatmentcapacity after just one limited injection.
16 18 ... the uranium concentration NMED notes that uranium concentrations had As discussed in the report, TPP reagent distribution wasdecreased from 5.25 mg/L to risen above baseline levels at the conclusion of limited in the X Area because of the lower permeability of the2.30 mg/L (at 15 DPI) at the data presented, and the lowest uranium aquifer in this area. In addition, due to the nature of the soil inXDR-I... concentration achieved in this well did not meet this area (finer-grained silts and clays), the TPP sorbs more
the applicable standard of 0.16 mg/L strongly onto the aquifer soil (TPP will sorb less to sands).Even with limited distribution, however, treatment efficacywas noted and was sustained for a period of time. Note that thepilot test involved only one injection, and with additionalinjections it is likely that reduction in uranium concentrationswill increase. At this full-scale the treatment of uranium in anarea with lower permeability, and greater ability to sorb andretard the injected TPP, would be treated over multipleinjections, and uranium mass-flux through the treatment zonewould be reduced significantly.
Homestake Mining Company of California8
Responses to NMED Comments Received Regarding the TPP Alluvial Pilot Testing Summary Report 20 November 2-014
Comment Page # Quoted Text NMED Comment ResponseNumber
17 19, Table These data demonstrate that Uranium concentrations at or below the aquifer- The lithology in the X Area was challenging due to the nature5, and the TPP amendment specific site standard of 0.16 mg/L were of the aquifer soil, consisting of a larger proportion of fine-
Appendix immobilized uranium in the achieved at only two wells in the X Area- grained material as compared to the S Area. The lowerD X Area, but overall injection well XIW and XDR-1. Post-treatment permeability in the X Area resulted in a limited volume of the
treatment efficiency was uranium concentrations that were achieved at aquifer around the injection well that was influenced by thesomewhat lower than XDR-2 appear to be steady at the conclusion of TPP injection, and likely significant movement of reagentobserved in the S Area. the data presented, but at concentrations through preferential flow paths, limiting the establishment of a
approximately twice the applicable standard. cohesive treatment zone.Analytical data from other X Area wellsindicate no, or at best, transient reduction to At the full-scale, lithologic variability will be addressed byuranium concentrations. In contrast to baseline screening multiple intervals with short-screens to targeturanium concentrations in S Area wells, discrete intervals (where appropriate and depending upon wellbaseline uranium concentrations in the X Area logs during well installation) and also through the use ofwere much higher, ranging from 4.63 mg/L in extraction wells coupled with injection wells to recirculateXIW at -70 DPI to 9.33 mg/L in XMW-4 at -I I water through the treatment zone to overcome this variabilityDPI. and achieve expanded distribution of injected reagent.
Please address how the design of a full-scaletreatment system can account for both lithologicvariability of pre-treatment baseline uraniumconcentrations.
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0Responses to NMED Comments Received Regarding the TPP Alluvial Pilot Testing Summary Report 20 November 2014
Comment Page # Quoted Text NMED Comment ResponseNumber
18 21-22 Arsenic NMED observes that breakthrough of the Although arsenic concentrations increased during the injectioninjection solution in the S Area is apparently period, they attenuated after injection and arseniccharacterized by an order-of-magnitude increase concentration increases were confined to within the test areain arsenic concentrations in SDR-IS and SDR- (changes in arsenic concentrations from baseline conditionsI D, and SMW-I, SMW-3D, SMW-4S, and were not noted downgradient at SMW-5S or SMW-5D).possibly SMW-3S; these increases were onlyslightly diminished over the remainder of the test The increase in arsenic concentrations was expected, due toperiod. Although the increased arsenic the displacement of naturally-occurring arsenic (in soil) byconcentrations in the monitoring wells remained orthophosphate. Outside of the influence of orthophosphate,at least one order-of-magnitude below the however, arsenic rapidly attenuates with distancestandard of 0.1 mg/L promulgated in downgradient from the injection well because orthophosphate20.6.2.3103 NMAC, these data would suggest is very reactive with calcium and other aquifer soil minerals,that characterization of baseline arsenic resulting in orthophosphate precipitation.concentrations should be included in thedetermination of areas of the aquifer that are Arsenic baseline characterization through the TPP treatmentsuitable for TPP treatment implementation. area will be an important part of any treatment
implementation, as will close monitoring of arsenicconcentrations during operation of the TPP system. Arsenicwill be controlled by lowering the TPP concentration andallowing orthophosphate to react and attenuate in the aquifer.
19 23 Sustained treatment without As noted above, uranium concentrations in Treatment efficacy was most noticeable within the treatmentrebound in uranium several wells did show rebounded uranium zone established by the TPP injection (within the radius ofconcentrations [in the S concentrations. HMC must explain how such influence of the injected reagent). Fluctuations in treatmentArea] indicated that uneven efficacy can be addressed in any performance are due to a number of factors, particularly thedissolved uranium was proposed full-scale implementation of this limited aquifer volume over which the treatment zone wastransported into the treatment process. established. At the full-scale, the treatment volume will betreatment zone from expanded laterally such that a cohesive barrier is established,upgradient and was and routine follow-up injections of TPP will be performed toimmobilized by phosphate continue to maintain treatment longevity (to replenish any lossprecipitates. of treatment capacity by the barrier). The frequency of follow-
up injections is expected to be finite, as uranium mass fluxthrough the barrier diminishes with treatment progress.
Homestake Mining Company of California10
Responses to NMED Comments Received Regarding the TPP Alluvial Pilot Testing Summary Report 20 November 2014
Comment Figure HMC ResponseNumber Number NMED Comment
20 4 Please explain the mechanism of coprecipitation, which is Co-precipitation involves the simultaneous precipitation of uranium withindicated to be applicable to uranium removal through calcium phosphate (apatite). In this process uranium is incorporated intoprecipitation of apatite, but for which uranium is not shown to apatite. Uranium may also sorb to apatite; this is more likely in the treatmentbe included in the chemical formula, zone when uranium has already been removed through formation of autinite
(calcium-uranium-phosphate) or apatite with incorporated uranium. In theAdsorptive bonds, as are indicated to be partially operable for presence of excess phosphate relative to uranium, calcium will react and formuranium removal by apatite, generally are weaker than inclusion apatite. Uranium dissolved in water that enters the treatment zone from
in the crystal matrix of uranyl phosphate precipitates. Please updgradient, can then sorb to apatite. Uranium sorption to apatite is generally
describe what controls the proportion of uranyl phosphate strong and, once sorbed, displacement of uranium may only occur under
formation over the other possible reactive products. extremes in pH. Additional details on the mechanism of uranium sorption andincorporation into apatite are provided in the following references: Fuller,C.C., J.R. Bargar, and J.A. Davis. 2003. Molecular-scale characterization ofuranium sorption by bone apatite materials for a permeable reactive barrierdemonstration. Environmental Science & Technology 37, no. 20: 4642-4649.DOI: 10.1021/es0343959.Fuller, C.C., J.R. Bargar, J.A. Davis, and M.J. Piana. 2002. Mechanisms ofuranium interactions with hydroxyapatite: Implications for groundwaterremediation. Environmental Science & Technology 36, no. 2: 158-165. DOI:10.1021/esO108483.
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Responses to NMED Comments Received Regarding the TPP Alluvial Pilot Testing Summary Report 20 November 21014
Appendix B
Comment Page # Quoted Text NMED Comment ResponseNumber
21 9 The declines in [uranium] NMED notes that samples that were analyzed by Uranium removal from groundwater within the area targetedconcentration [in ground scanning electron microscopy and energy by the TPP injection occurred through precipitation reactionswater] were attributed to dispersive X-ray spectroscopy "did not show with orthophosphate, as described above. The inability touranium precipitation uranium," although HMC qualifies this directly recover these precipitates from within the treatmentthrough direct reaction with observation with the further notes these zone is not surprising due to the relatively large area oversoluble phosphate to form methodologies focus upon "limited area of a soil which the uranium precipitates within the treatment volume,uranium phosphate, and sample" (p. 8). Still, implementation of this and the very low concentration of resultant uranium in thethrough co-precipitation and remedial technology at full-scale will require aquifer soil after treatment. As discussed in Appendix B, theincorporation into calcium some direct observations about where and in lack of high-concentration zones of uranium precipitates isphosphate.. .While these what forms the uranium will be sequestered beneficial to the overall technology as uranium and phosphatemineral phases were not within the aquifer. minerals can be precipitated without creating significant loss indirectly identified in the soil permeability within the treatment zone.coring and analysis work,this is likely due to their The next phase of pilot testing will involve laboratory columnpresence in limited tests to simulate the aquifer system, with TPP applied to theconcentrations and column along with flowing groundwater recovered from theheterogeneity in distribution test area. After uranium is precipitated within the column,at the micron scale. additional studies will be done to evaluate the uranium
precipitated within the column, including an effort to furthercharacterize and identify the uranium minerals that formthrough TPP application. At the column scale the uraniumprecipitates should be readily identified.
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Responses to NMED Comments Received Regarding the TPP Alluvial Pilot Testing Summary Report 20 November 2014
Appendix C
Comment Page # Quoted Text NMED Comment ResponseNumber
22 5., Figure Uranium concentrations Please address the observation from Figure C-3 As shown in Figure C-3, during the "pull" phase of the push-C-3 during the pull phase were that uranium concentrations show an increasing pull test, additional pore volumes were removed beyond those22 below the baseline trend, ending above the baseline concentration at added during the "push" phase. The additional pore volumes
concentration of the conclusion of the data presented that were recovered likely were from the area of the aquifer0.05...mg/L, dropping to as outside of the treatment zone, resulting in an increase inlow as 0.038 mg/L... uranium concentrations at the conclusion of the test.
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Homestake's Responses to NMED's Comments Received 22 September 2014 Pertainingto Homestake's TPP Alluvial Pilot Testing Summary Report dated 3 July 2014
Attachment I - Stability of uranium phosphate minerals
The Eh-pH diagram (a) shows the stability of meta-autinite (barium-uranium-phosphate) acrossredox potential (Eh) and pH. This form of meta-autinite is present in the Coles Hill uranium oredeposit in Virginia, and is similar to calcium-uranium-phosphate (in this case barium replacescalcium). The stability of this uranium mineral phase extends to pH -8 when phosphate ispresent in excess relative to bicarbonate (as shown in diagram (b)). In the case of the
tripolyphosphate (TPP) alternative groundwater restoration strategy for the Grants ReclamationProject, this condition (excess phosphate relative to carbonate to promote formation of autiniteminerals) is brought about through the addition of TPP to groundwater. The Coles Hill uraniumdeposit has a large component of the ore that is phosphate-based; this demonstrates thestability of the uranium phosphate minerals over geologic time. Source: Jerden, J.L., and Sinha,A.K. 2003. Phosphate based immobilization of uranium in an oxidizing bedrock aquifer. AppliedGeochemistry 18: 823-843. Additional information on the solubility product of autinite and uranylhydrogen phosphate is provided in Lewis-Gorman, D., Shvareva, T., Kubato, K., Burns, P.C.,Wellman, D.M., McNamara, B., Szymanowski, J.E.S., Navrotsky, A., and Fein, J.B. 2009.Thermodynamic properties of autinie, uranyl hydrogen phosphate, and uranyl orthophosphatefrom solubility and calorimetric measurements. Environmental Science and Technology 43:7416-7422.
WHomestake's Responses to NMED's Comments Received 22 September 2014 Pertaining toHomestake's TPP Alluvial Pilot Testing Summary Report dated 3 July 2014
Attachment 2 - Analytical data for all analytes monitored during the TPP alluvial pilot test
0 08/27/2013 Start of Injections: 8/21/2013Slw-S End of Injections:
Days Elapsed Since End of Injections: -69 0 161 42 86 182
BaselineParameters Type Units 61190013 81,72013 912013 10/8/2013 11/21/2013 212512014
General ChemistryAlkalinity, Total as CaCO3 mg/L N/A N/ACarbonate as C03 mg/L <5 <5Nitrogen, Nitrate-Nitrite as N mg/L 1.67 1.45pH s.u. 7.38 7.29Solids. Total Dissolved Calculated mg/L 2500 2500Solids, Total Dissolved TDS @ 180 C mg/L 2580 2470TDS Balance 10.80 - 1.20) unitless 1.04 1
Additional Performance ParametersArsenic Total mg/L N/A N/AArsenic Dissolved mg/IL 0.041 0.03Phosphorus, Ortho as P, dissolved Dissolved mg/L 5.2 8Phosphorus, Total as P Total mg/L 6.7 6.14Radium 226 pCi/L 0.61 0.47Radium 226 altu uCi/mL 6.00E-10 5,O0E-10Radium 226 altu MDC uCi/mL 2.00E-10 2.OOE-10Radium 226 altu precision (±) uCi/mL 2.00E-10 2.O0E-10Radium 226 MDC pCi/L 0.17 0.19Radium 226 precision (±) pCi/L 0.18 0.17
Notes:
meq/L = milliequivalents per litermg/L = milligrams per liter
N/A = not analyzed
pCi/L = picocuries per liter
s.u. = standard unituCi/mL = microcuries per milliliter< = value is less than the provided laboratory method reporting limit
0 0XDR-2 End of Injections: 8127/2013 Start of Injection: 8121/2013
Days Elapsed Since End of Injections: Baseline70 Baseline-11 '-5 1 7 9/11 15 22 34 55 70 112 148 182
Parameters Type Units 6/18/2013 8116/1221 2013 8/28/2013 9/3/2013 112013 9/18/2013 9/30/2013 10/21/2013 11/5/2013 122013 013 1/22/2014 2/25/2014
uCi/mL = microcuries per milliliter< = value is less than the provided laboratory method reporting limit
NEW MEXICOENVIRONMENT DEPARTMENT
Harold Runnels Building1190 St. Francis Drive
P.O. Box 5469, Santa Fe, New Mexico 87502-5469Phone (505) 827-2855 Fax (505) 827-2965
www.nmenv.state.nm usSUSANA MARTINEZGovernor
JOHN A. SANCHEZLieutenant Governor
RYAN FLYNNSecretary
BUTCH TONGATEDeputy Secretary
CERTIFIED MAIL-RETURN RECEIPT REQUESTED
September 22, 2014
Jesse Toepfer, Closure ManagerHomestake Mining Company of CaliforniaP.O. Box 98Grants, NM 87020
RE: Homestake Mining Company of California uranium millsitelDP-200-Comments from NMED's review of "Responses to NMED commentsregarding Homestake's November 2013 'Update on treatment activities"'(August 21, 2014) and "TPP [Tripolyphosphate] alluvial pilot testingsummary report" (July 3, 2014)
Dear Mr. Toepfer:
During preparation of comments on the above-referenced July 3, 2014 report ("Report"),the New Mexico Environment Department (NMED) received Homestake MiningCompany of California's (HMC's) August 21, 2014 responses to NMED comments onthe November 2013 report, which included a brief overview of HMC's TPP testing. Forexpediency, NMED is including herein comments only for the TPP section from HMC'sAugust 21, 2014 submittal. Additional comments on other sections of HMC's August21, 2014 submittal will be forthcoming in a separate letter.
"Responses to NMED comments regarding Homestake's November 2013 'Updateon treatment activities"' (August 21, 2014)
E Quoted text NMED comments
This difference in retardation and Another important consideration forachievable distribution is an the development of a "barrier" also
1 important consideration for continued should include amount and rate ofapplication of the technology-the orthophosphate formation todesign.. .of a transect of injection precipitate sufficient uranium to
Jesse Toepfer, Homestake Mining Company of CaliforniaRE: Homestake Mining Company of California uranium millsitelDP-200--Comments from NMED's review of "Responses
to NMED comments regarding Homestake's November 2013 'Update on treatment activities"' (August 21, 2014) and"TPP [Tripolyphosphate] alluvial pilot testing summary report (July 3, 2014)
September 22, 2014
E Quoted text NMED comments
points to create a "barrier" will ensure achieve the uranium concentrationcomplete lateral distribution between standard considering continuedthe points, influx of background uranium
concentrations.The uranium-phosphate precipitates On page 20 of the Report, HMCthat form during TPP injection have stated that it was unable to directlyvery low solubility under ambient identify the uranium and calciumaquifer conditions (Wellman et al. phosphate mineral phases during2005). soil coring and analysis. Therefore,
please explain the basis for this2 statement.
Since the mineral phases could notbe identified in this test phase,please explain how HMC canassure the long-term efficacy of anySproposed barrier.
"TPP alluvial pilot testing summary report" (July 3, 2014)Main report text
E Quoted text NMED comments
These uranium minerals have As previously noted, HMC hasvery low solubility under stated that the mineral phasesambient aquifer conditions... that are presumed to have
formed could not be identified
3 6 during analysis.
Please present stabilitydiagrams from authoritativegeochemical references toillustrate this stability under
Page 2/12
Jesse Toepfer, Homestake Mining Company of CaliforniaRE: Homestake Mining Company of California uranium millsitelDP-200-Comments from NMED's review of "Responses
to NMED comments regarding Homestake's November 2013 'Update on treatment activities"' (August 21, 2014) and"TPP [Tripolyphosphate] alluvial pilot testing summary report (July 3, 2014)
September 22. 2014
EQuoted text NMED comments
varying conditions of Eh, pH,temperature and pressure thatwould be expected in thenatural environment.
Not applicable Evaluation of tracerbreakthrough and washoutshould have included
4 7-10 characterization of the localground water gradients withineach test plot prior to theinception of tracer injection.
Water from nearby extraction Please address to what degreewells.. .was utilized to mix the the use of water with uraniuminjection solution. Measured concentrations in excess of theuranium concentrations in the alluvial aquifer site standard asinjectate solution.. .are within injectate may adversely impactthe range observed in other process effectiveness.wells proximal the pilot testareas...Following the injections [in the Please explain how theS area], 1,200 gallons of quantities of post-injectatewater from S4 was injected to solution water were determinedminimize precipitate build-up for each of the test plot areas.and potential fouling in the
6 12 injection well.. .Following the Please explain if any differenceinjections [in the X area] 100 in precipitate build-up andgallons of reverse osmosis fouling was noted between testwater was injected to plot areas S and X resultingminimize precipitate build-up from the different water sourcesand potential fouling in the that were used after injectate.injection well.Table 7 presents the targeted Data for achieved amendmentand achieved amendment concentrations at dose
7 14 concentrations for key response wells are not includedinjection solution parameters in this table. Please clarify(calcium and phosphorus) for where these data can bethe injectate solution and as viewed, as well as the stated
Page 3/12
Jesse Toepfer, Homestake Mining Company of CaliforniaRE: Homestake Mining Company of California uranium millsiteIDP-200-Comments from NMED's review of "Responses
to NMED comments regarding Homestake's November 2013 'Update on treatment activities"' (August 21, 2014) and"TPP [Tripolyphosphate] alluvial pilot testing summary report (July 3, 2014)
September 22, 2014
mE Quoted text NMED commentsE E3 a. 3utdtx
measured at the dose comparisons of in situ toresponse wells... In the S targeted concentrations.Area, in situ calciumconcentrations were 6 to 9times higher than targetedand TPP concentrations wereapproximately half of thetargeted concentration... Inthe X Area, in situ calciumconcentrations wereapproximately half of thetargeted values, while TPPconcentrations were twoorders of magnitude lowerthan targeted values (Table7). However the injectateconcentration of TPP wasapproximately the same astargeted injectate values.The difference between the The statement suggests thatachieved in situ more accurate control ofconcentrations of calcium and injectate reagents should bephosphorous and the targeted implemented in order to
8 14 concentrations is partially due achieve targeted dosageto batching variability.. .(likely distribution more accurately.due to coarse measurementof reagent masses [in theinjectate]).This [significantly reduced This observation suggests thatdistribution of TPP in the X subsurface stratigraphic andArea] is consistent with the structural variations (e.g.,finer aquifer grain texture intercalated clay layers,
9 15 observed in the X Area fractures) might also influencethe distribution of reagents.Please indicate how this couldbe addressed in a full-scaleimplementation.
Page 4/12
Jesse Toepfer, Homestake Mining Company of CaliforniaRE: Homestake Mining Company of California uranium millsitelDP-200-Comments from NMED's review of "Responses
to NMED comments regarding Homestake's November 2013 'Update on treatment activities"' (August 21, 2014) and"TPP [Tripolyphosphate] alluvial pilot testing summary report (July 3, 2014)
September 22, 2014
4.')
E 50E E E Quoted text NMED comments0E .
Breakthrough of the injectionsolution [in S Area doseresponse and monitoringwells] was also characterizedby increased concentrationsof TDS, chloride, calcium,total phosphorous, andorthophosphate (Table 4). Indose response wells SDR-1Sand SDR-1 D, peak TDS andchloride concentrations wereapproximately 20 and 60times higher than baselinevalues, respectively
10
15, Table4, and
AppendixD
Few pre-injection/baseline datafor the cited analytes are shownwithout explanation for wellsSDR-1 S (no analytical data forTDS and chloride), SDR-1 D (1analysis each for TDS andchloride; 2 for calcium). Thesedata gaps make difficult theevaluation of statements thatfollow, which compare post-breakthrough concentrations topre-injection/baselineconcentrations. Please explainhow the baseline datapresented in this Report wouldbe sufficient for this study inlight of these observations.
Please discuss the significanceof the last recorded dissolvedmolybdenum concentration of52 mg/I in well SDR-4S at 147DPI, which is two orders ofmagnitude greater than anyprevious analyses.
NMED notes that no analyticaldata are included for radium,thorium, sulfate, and nitrate inTable 4, although data forsulfate concentrations areshown in the charts ofAppendix D. All of theseconstituents have aquifer-specific site standards.Possible impact of the TPPprocess on concentrations of
Page 5/12
Jesse Toepfer, Homestake Mining Company of CaliforniaRE: Homestake Mining Company of California uranium millsiteIDP-200-Comments from NMED's review of "Responses
to NMED comments regarding Homestake's November 2013 'Update on treatment activities"' (August 21, 2014) and"TPP [Tripolyphosphate] alluvial pilot testing summary report (July 3, 2014)
September 22, 2014
E w. Quoted text NMED comments
these constituents should beinvestigated and discussed inthe pilot testing phase activities.
[Tracer] Washout was slow in Please explain the significance,all [X area] dose response if any, of observed tracer
11 16 wells... washout rates with respect toperformance of the TPPprocess.
Breakthrough of the injection As for monitor wells in the Ssolution [within the X area area (see Comment 10 above),dose response wells] was few pre-injection/baseline dataalso characterized by for TDS and chloride are shownincreased concentrations of without explanation for wellsTDS, chloride, and calcium... XDR-1, XDR-2 XDR-3, and
XDR-4 (1 analysis each).These data gaps make difficultthe evaluation of statementsthat follow, which compare
16, Table post-breakthrough
12 5, and concentrations to pre-Appendix injection/baseline
D concentrations. Please explainhow the baseline datapresented in this Report wouldbe sufficient for this study inlight of these observations.
As stated previously, the pilottesting process should includeall analytes for which aquifer-specific site standards areestablished.
At SMW-1, the uranium Although uranium17, Table concentrations decreased concentrations did diminish to
13 4, and from 1.44 mg/L to 0.047 mg/L 0.047 mg/L at 15 DPI as stated,Figure 8 (at 15 DPI). The high NMED notes that
uranium concentration concentrations immediately
Page 6/12
Jesse Toepfer, Homestake Mining Company of CaliforniaRE: Homestake Mining Company of California uranium millsitelDP-200-Comments from NMED's review of "Responses
to NMED comments regarding Homestake's November 2013 'Update on treatment activities"' (August 21, 2014) and"TPP [Tripolyphosphate] alluvial pilot testing summary report (July 3, 2014)
September 22, 2014
E E E Quoted text NMED comments
detected at only one point rebounded to above thepost-injection (at 20 DPI) in aquifer-specific site standard ofthis well is likely a laboratory 0.16 mg/L by 21 DPI, anderror. showed an increasing trend
through the remainder of datapresented.
The referenced high uraniumconcentrations of 1.56 is shownon Table 4 to occur at 15 DPI,not 20 DPI as stated herein.Please clarify this discrepancy.
Treatment trends at SMW-3S Please explain the significanceand SMW-4S are somewhat of this observation.
14 17 irregular; however, thesewells are downgradient fromthe injection wells...Uranium treatment remained NMED notes that uraniumhigh after the injection concentrations in SIW-D, SDR-solution had washed out... 1S, SMW-1 and possibly SMW-
4S appear to show rapidrebound from the lowesturanium concentrationsachieved to end atconcentrations near or above
17, Table the aquifer-specific site
15 4, and standard of 0.16 mg/L by the
Figure 8 end of the data presented.Also, as HMC notes, baselineuranium concentrations inthese wells ranged from justabove the referenced standardto approximately one order ofmagnitude above the standard.Therefore it would appear thatlong-term treatment efficacywas limited in this area.
Page 7/12
Jesse Toepfer. Homestake Mining Company of CaliforniaRE: Homestake Mining Company of California uranium millsitelDP-200--Comments from NMED's review of "Responses
to NMED comments regarding Homestake's November 2013 'Update on treatment activities"' (August 21, 2014) and"TPP [Tripolyphosphate] alluvial pilot testing summary report (July 3, 2014)
September 22, 2014
EO "E . E Quoted text NMED comments
...the uranium concentration NMED notes that uraniumdecreased from 5.25 mg/I to concentrations had risen above2.30 mg/I (at 15 DPI) at XDR- baseline levels at the1... conclusion of the data
16 18 presented, and that the lowesturanium concentrationachieved in this well did notmeet the applicable standard of0.16 mg/L.
These data demonstrate that Uranium concentrations at orthe TPP amendment below the aquifer-specific siteimmobilized uranium in the X standard of 0.16 mg/I wereArea, but overall treatment achieved at only two wells inefficiency was somewhat the X Area-injection well XIWlower than observed in the S and XDR-1. Post-treatmentArea. uranium concentrations that
were achieved at XDR-2appear to be steady at theconclusion of the datapresented, but atconcentrations approximately
19, Table twice the applicable standard.
17 5, and Analytical data from other XAppendix Area wells indicate no, or at
D best, transient reduction touranium concentrations. Incontrast to baseline uraniumconcentrations in S Area wells,baseline uraniumconcentrations in the X Areawere much higher, ranging from4.63 mg/L in XIW at -70 DPI to9.33 mg/L in XMW-4 at -11DPI.
Please address how the designof a full-scale treatment system
Page 8/12
Jesse Toepfer, Homestake Mining Company of CaliforniaRE: Homestake Mining Company of California uranium milisltelDP-200-Comments from NMED's review of "Responses
to NMED comments regarding Homestake's November 2013 'Update on treatment activities.' (August 21, 2014) and"TPP [Tripolyphosphate] alluvial pilot testing summaryreport (July 3, 2014)
September 22, 2014
E E E Quoted text NMED comments
can account for both lithologicvariability and the variability ofpre-treatment baseline uraniumconcentrations.
Arsenic NMED observes thatbreakthrough of the injectionsolution in the S Area isapparently characterized by anorder-of-magnitude increase inarsenic concentrations in SDR-1S and SDR-1D, and SMW-1,SMW-3D, SMW-4S, andpossibly SMW-3S; theseincreases were only slightlydiminished over the remainderof the test period. Although the
18 21-22 increased arsenicconcentrations in themonitoring wells remained atleast one order-of-magnitudebelow the standard of 0.1 mg/Ipromulgated in 20.6.2.3103NIMAC, these data wouldsuggest that characterization ofbaseline arsenic concentrationsshould be included in thedetermination of areas of theaquifer that are suitable for TPPtreatment implementation.
Sustained treatment without As noted above, uraniumrebound in uranium concentrations in several wellsconcentrations [in the S Area] did show rebounded uraniumindicated that dissolved concentrations. HMC musturanium was transported into explain how such uneventhe treatment zone from efficacy can be addressed inupgradient and was any proposed full-scaleimmobilized by the phosphate implementation of this
Page 9/12
Jesse Toepfer, Homestake Mining Company of CaliforniaRE: Homestake Mining Company of California uranium millsite/DP-200-Comments from NMED's review of "Responses
to NMED comments regarding Homestake's November 2013 'Update on treatment activities"' (August 21, 2014) and"TPP [Tripolyphosphate] alluvial pilot testing summary report (July 3, 2014)
September 22, 2014
E E'E Quoted text NMED comments
CL)
precipitates, treatment process.
Main text figures
oE "E I E NMED comments
Please explain the mechanism of coprecipitation, which is indicatedto be applicable to uranium removal through precipitation of apatite,but for which uranium is not shown to be included in the chemicalformula.
20 4 Adsorptive bonds, as are indicated to be partially operable for
uranium removal by apatite, generally are weaker than inclusion inthe crystal matrix of uranyl phosphate precipitates. Please describewhat controls the proportion of uranyl phosphate formation over theother possible reactive products.
Page 10/12
Jesse Toepfer, Homestake Mining Company of CaliforniaRE: Homestake Mining Company of California uranium millsitelDP-200-Comments from NMED's review of "Responses
to NMED comments regarding Homestake's November 2013 'Update on treatment activities.' (August 21, 2014) and"TPP [Trlpolyphosphate] alluvial pilot testing summary report (July 3, 2014)
September 22, 2014
Appendix B
4i) t 0 4)E E . ") E Quoted text NMED comments
The declines in [uranium] NMED notes that samples thatconcentration [in ground water] were analyzed by scanningwere attributed to uranium electron microscopy and energyprecipitation through direct dispersive X-ray spectroscopyreaction with soluble phosphate "did not show uranium," althoughto form uranium phosphate, and HMC qualifies this observationthrough co-precipitation and with the further note these
21 9 incorporation into calcium methodologies focus uponphosphate.. .While these "limited area of a soil sample" (p.mineral phases were not 8). Still, implementation of thisdirectly identified in the soil remedial technology at full-scalecoring and analysis work, this is will require some directlikely due to their presence in observations about where and inlimited concentrations and what forms the uranium will beheterogeneity in distribution at sequestered within the aquifer.the micron scale.
Appendix C
E Quoted text NMED comments
Uranium concentrations Please address the observationduring the pull phase were from Figure C-3 that uranium
5 below the baseline concentrations show an22 FC-3 concentration of 0.05.. .mg/L, increasing trend, ending above
dropping to as low as 0.038 the baseline concentration at themg/L... conclusion of the data
presented.
Page 11/12
Jesse Toepfer, Homestake Mining Company of CaliforniaRE: Homestake Mining Company of California uranium millsitelDP-200-Comments from NMED's review of "Responses
to NMED comments regarding Homestake's November 2013 'Update on treatment activities"' (August 21, 2014) and"TPP [Tripolyphosphate] alluvial pilot testing summary report (July 3, 2014)
September 22, 2014
Please submit additional information to respond to these comments within 60 days ofthis letter. Please contact me by telephone at (505) 476-3777 or atdavid.mayerson(,state.nm.us if you have any questions.
Sincerely,
Mining Environmental Compliance SectionGround Water Quality BureauNew Mexico Environment Department