DRC-2021-006862 - 0901a06880e9335e

DRC-2021-006862 195 North 1950 West • Salt Lake City, UT Mailing Address: P.O. Box 144880 • Salt Lake City, UT 84114-4880 Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah
SPENCER J. COX Governor DEIDRE HENDERSON Lieutenant Governor
Department of Environmental Quality
Kimberly D. Shelley Executive Director
DIVISION OF WASTE MANAGEMENT AND RADIATION CONTROL Douglas J. Hansen Director May 21, 2021
Kathy Weinel, Quality Assurance Manager
Energy Fuels Resources (USA) Inc.
225 Union Blvd. Suite 600 Lakewood, CO 80228 RE: Energy Fuels Resources (USA) Inc., March 4, 2021 Background Report for Monitoring Wells MW-38, MW-39, and MW-40 White Mesa Uranium Mill (Mill):
Utah Groundwater Discharge Permit No. UGW370004 (Permit) Dear Ms. Weinel:
The Division of Waste Management and Radiation Control (“DWMRC”) has reviewed the Energy Fuels
Resources (USA) Inc. (“EFR”) May 1, 2014 document titled Background Groundwater Quality Report
for Monitoring Wells MW-38, MW-39, and MW-40, White Mesa Uranium Mill (“Report”). The Report was prepared to comply with Utah Ground Water Discharge Permit No. UGW370004 (“Permit”) Part I.H.1. Class III Groundwater: Based on average TDS concentrations, groundwater in monitoring wells MW-38, MW-39 and MW-40 is defined as the Class III Protection Level. Per Utah Administrative Code (“UAC”) R317-6-4.6,
Class III groundwater protection levels shall be based on criteria summarized in the table below:

Groundwater Class TDS Limit
Groundwater Protection Levels
Undetectable Contaminant
(greatest of)
Detectable Contaminant (greatest of)
III 1.25 x BG 0.5 x GWQS MDL 1.5 x BG Mean + 2α 0.5 x GWQS

Page 2
Monitoring Frequency:
Groundwater velocities were based on estimations of hydraulic conductivity and specific storage
calculated with the use of the Kansas Geological Survey (“KGS”) Model, and field slug testing measurements (falling head). Per review of the slug test results tables for each of the monitoring wells, it appears that the measured values correspond to the values submitted with the background monitoring report1.
Based on these calculations and per criteria listed in the Permit Part I.E., groundwater samples are to be collected at the following frequencies.
• Semi-annual (2 times/year) where groundwater velocity is less than 10 feet/year, and,
• Quarterly (4 times/year) where groundwater velocity is equal to or greater than 10 feet/year. Based on the calculated groundwater pore velocities discussed above (with consideration to best professional judgement for MW-40), the required monitoring frequencies for monitoring wells MW-38, MW-39, and MW-40 are listed on the table below.

Monitoring Well No. Monitoring Frequency Groundwater Velocity
(ft/yr)
MW-38 Semi-Annual 6.08 MW-39 Semi Annual 1.42
MW-40 Semi Annual* 10.2*
*The groundwater pore velocity is above 10 feet/year for well MW-40; however, the reported value is
10.2 feet/year which does not warrant quarterly monitoring based on professional judgement and location of the well hydraulically cross-gradient from tailings disposal. Groundwater Compliance Limits (GWCL’s):

The tables below summarize the calculated and approved GWCL’s for monitoring wells MW-38, MW-39 and MW-40. The proposed GWCL’s are approved unless otherwise noted in the DWMRC Adjustment column. DWMRC notes that most of the GWCL’s were calculated according to fractions of the Ground Water Quality Standards (“GWQS’s”) which are listed in the facility Ground water Discharge Permit No. UGW370004 (“Permit”). These are based on either GWQS’s listed in Utah
Administrative Code R317-6 or as noted in footnotes of the Permit Tables in Part I.C. In cases where other methods were used it was verified that the proposed GWCL’s were calculated in conformance with the approved statistical flow chart2 and U.S. Environmental Protection Agency Statistical Guidance3.

1 Hydro Geo Chem, Inc. June 12, 2018. Installation and Hydraulic Testing of Perched Monitoring Wells MW-38, MW-39 and MW-40 White Mesa Uranium Mill Near Blanding, Utah. 2 Intera, 2007, Groundwater Data Preparation and Statistical Process Flow for Calculating Groundwater Protection Standards, White Mesa Mill Site, San Juan County, Utah 3 United States Environmental Protection Agency, 2009, Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities, Unified Guidance EPA530/R-09-007
Page 3

Monitoring Well MW-38
Parameter Proposed GWCL GWQS Method DWMRC Adjustment
Ammonia 12.5 mg/L 25 mg/L Fractional
Nitrate/Nitrite 16.04 mg/L 10 mg/L Mean + 2α
Arsenic 25 µg/L 50 µg/L Fractional
Beryllium 2 µg/L 4 µg/L Fractional Cadmium 2.5 µg/L 5 µg/L Fractional
Chromium 50 µg/L 100 µg/L Fractional
Cobalt 365 µg/L 730 µg/L Fractional
Copper 650 µg/L 1,300 µg/L Fractional
Iron 5500 µg/L 11,000 µg/L Fractional
Lead 7.5 µg/L 15 µg/L Fractional
Manganese 400 µg/L 800 µg/L Fractional
Mercury 1.39 µg/L 2 µg/L Poisson Prediction Limit
Molybdenum 20 µg/L 40 µg/L Fractional
Nickel 16.25 µg/L 10 µg/L Poisson
Prediction Limit

Selenium 178.74 µg/L 50 µg/L Mean + 2α
Silver 50 µg/L 100 µg/L Fractional Thallium 1.39 µg/L 2 µg/L Poisson Prediction Limit
Tin 8,500 µg/L 17,000 µg/L Fractional
Uranium 7.16 µg/L 30 µg/L Mean + 2α
Vanadium 30 µg/L 60 µg/L Fractional Zinc 2,500 µg/L 5,000 µg/L Fractional
Gross Alpha 7.5 pCi/L 15 pCi/L Fractional
Acetone 350 µg/L 700 µg/L Fractional
Benzene 2.5 µg/L 5 µg/L Fractional
Methyl Ethyl
Ketone
2,000 µg/L 4,000 µg/L Fractional
Carbon
Tetrachloride
2.5 µg/L 5 µg/L Fractional
Chloroform 35 µg/L 70 µg/L Fractional
Chloromethane 15 µg/L 30 µg/L Fractional
Methylene Chloride 2.5 µg/L 5 µg/L Fractional
Naphthalene 50 µg/L 100 µg/L Fractional
Tetrahydrofuran 23 µg/L 46 µg/L Fractional
Toluene 500 µg/L 1,000 µg/L Fractional
Xylenes, Total 5,000 µg/L 10,000 µg/L Fractional
Chloride 48.7 mg/L Mean + 2α
Fluoride 0.98 mg/L 4 mg/L Mean + 2α Field pH 7.6 S.U. Mean + 2α 6.5 – 8.5 S.U GWQS
Page 4

Monitoring Well MW-38
Parameter Proposed GWCL GWQS Method DWMRC Adjustment
Sulfate 3126.75 mg/L HHV**
TDS 5008.75 mg/L 1.25 X Mean (1.25 X BG*)
*BG = Background **HHV= Highest Historical Value

Monitoring Well MW-39
Parameter Proposed GWCL GWQS Method DWMRC
Adjustment
Ammonia 0.33 mg/L 25 mg/L Mean + 2α
Nitrate/Nitrite 5 mg/L 10 mg/L Fractional Arsenic 25 µg/L 50 µg/L Fractional
Beryllium 5.97 µg/L 4 µg/L Mean + 2α
Cadmium 3.01 µg/L 5 µg/L Mean + 2α
Chromium 50 µg/L 100 µg/L Fractional
Cobalt 79.17 µg/L 730 µg/L Mean + 2α
Copper 35.55 µg/L 1,300 µg/L Mean + 2α
Iron 15506.23 µg/L 11,000 µg/L Mean + 2α Lead 7.5 µg/L 15 µg/L Fractional
Manganese 2320 µg/L 800 µg/L HHV
Mercury 1.39 µg/L 2 µg/L Poisson Prediction Limit
Molybdenum 20 µg/L 40 µg/L Fractional
Nickel 39.25 µg/L 100 µg/L Mean + 2α
Selenium 25 µg/L 50 µg/L Mean + 2α
Silver 50 µg/L 100 µg/L Fractional Thallium 3.82 µg/L 2 µg/L Mean + 2α
Tin 8,500 µg/L 17,000 µg/L Fractional
Uranium 13.95 µg/L 30 µg/L Mean + 2α Vanadium 30 µg/L 60 µg/L Fractional
Zinc 259 µg/L 5,000 µg/L Mean + 2α
Gross Alpha 5.47 pCi/L 15 pCi/L Mean + 2α
Acetone 350 µg/L 700 µg/L Fractional
Benzene 2.5 µg/L 5 µg/L Fractional
Methyl Ethyl
Ketone
2,000 µg/L 4,000 µg/L Fractional
Carbon Tetrachloride 2.5 µg/L 5 µg/L Fractional
Chloroform 35 µg/L 70 µg/L Fractional Chloromethane 15 µg/L 30 µg/L Fractional
Methylene Chloride 2.5 µg/L 5 µg/L Fractional
Naphthalene 50 µg/L 100 µg/L Fractional
Tetrahydrofuran 23 µg/L 46 µg/L Fractional
Page 5

Monitoring Well MW-39
Parameter Proposed GWCL GWQS Method DWMRC Adjustment
Toluene 500 µg/L 1,000 µg/L Fractional
Xylenes, Total 5,000 µg/L 10,000 µg/L Fractional
Chloride 43.68 mg/L Mean + 2α
Fluoride 0.82 mg/L 4 mg/L Mean + 2α Field pH 4.51 S.U. Mean + 2α 4.51 – 8.5 S.U.
Sulfate 3522.07 mg/L Mean + 2α
TDS 4,713.48 mg/L Mean + 4α 1.25 X BG = 5270 mg/L

Monitoring Well MW-40
Parameter Proposed GWCL GWQS Method DWMRC
Adjustment
Ammonia 12.5 mg/L 25 mg/L Fractional
Nitrate/Nitrite 3.41 mg/L 10 mg/L Mean + 2α Arsenic 25 µg/L 50 µg/L Fractional
Beryllium 2 µg/L 4 µg/L Fractional
Cadmium 2.5 µg/L 5 µg/L Fractional
Chromium 50 µg/L 100 µg/L Fractional
Cobalt 365 µg/L 730 µg/L Fractional
Copper 650 µg/L 1,300 µg/L Fractional
Iron 5,500 µg/L 11,000 µg/L Fractional
Lead 7.5 µg/L 15 µg/L Fractional
Manganese 400 µg/L 800 µg/L Fractional
Mercury 1.39 µg/L 2 µg/L Poisson Prediction Limit
Molybdenum 20 µg/L 40 µg/L Fractional Nickel 50 µg/L 100 µg/L Fractional
Selenium 240.75 µg/L 50 µg/L 1.5 X Mean (1.5 X BG)

Silver 50 µg/L 100 µg/L Fractional
Thallium 1 µg/L 2 µg/L Fractional Tin 8,500 µg/L 17,000 µg/L Fractional
Uranium 28.92 µg/L 30 µg/L Mean + 2α
Vanadium 30 µg/L 60 µg/L Fractional
Zinc 2500 µg/L 5,000 µg/L Fractional
Gross Alpha 1.15 pCi/L 15 pCi/L Mean + 2α
Acetone 350 µg/L 700 µg/L Fractional
Benzene 2.5 µg/L 5 µg/L Fractional Methyl Ethyl Ketone 2,000 µg/L 4,000 µg/L Fractional
Carbon Tetrachloride 2.5 µg/L 5 µg/L Fractional
Chloroform 35 µg/L 70 µg/L Fractional
Page 6

Monitoring Well MW-40
Parameter Proposed GWCL GWQS Method DWMRC Adjustment
Chloromethane 15 µg/L 30 µg/L Fractional
Methylene Chloride 2.5 µg/L 5 µg/L Fractional
Naphthalene 50 µg/L 100 µg/L Fractional
Tetrahydrofuran 23 µg/L 46 µg/L Fractional
Toluene 500 µg/L 1,000 µg/L Fractional Xylenes, Total 5,000 µg/L 10,000 µg/L Fractional
Chloride 49.20 mg/L Mean + 2α
Fluoride 0.86 mg/L 4 mg/L Mean + 2α Field pH 7.26 S.U. Mean + 2α 6.5 – 8.5 S.U.
Sulfate 2680.35 mg/L Mean + 2α
TDS 3848.65 mg/L Mean + 2α 1.25 x BG =
4337.5 mg/L

Monitoring Well Designation:
A conference call was held on May 17, 2021 between DWMRC and EFRI to discuss the findings of the Report review and GWCL’s discussed above, and to discuss whether MW-38, MW-39 and MW-40 will be included in the Permit as Compliance Monitoring Wells or General Monitoring Wells.
DWMRC recognizes that wells MW-38, MW-39, and MW-40 are currently cross gradient from potential tailings cell discharge (per current groundwater monitoring head data and groundwater contour mapping) and there is no indication of Mill caused groundwater impacts in the wells. However, DWMRC explained that current Mill conditions may warrant a compliance well designation for MW-38,
MW-39, and MW-40 when considering the background concentrations and the expansion of future
tailings disposal further down the mesa. Specifically: 1. Several constituents in MW-38, MW-39 and MW-40 were noted to be in exceedance of State Water Quality Standards (GWQS’s). Beryllium, iron, manganese, thallium, and pH were noted to be above GWQS’s at MW-39 in addition to selenium at both MW-38 and MW-40 and Nitrate
+ Nitrite (as N) at MW-38.
2. EFRI has applied for approval of new tailings cells 5A and 5B which are planned to be constructed to the south of current cells 4A and 4B. Monitoring wells MW-38, MW-39 and MW-40 will be useful as downgradient/cross-gradient compliance wells for tailings cells 5A and
5B when considering the southern extension. MW-38, MW-39 and MW-40 would be useful as
an addition to the closer downgradient wells submitted for installation/monitoring of per locations in the EFRI application to ensure that the eastern cross gradient wells continue to conform to background data findings.
3. Per DWMRC review of the MW-38, MW-39, and MW-40 background data, only two constituents are demonstrating significant increasing trends, TDS in monitoring well MW-38 and
selenium in monitoring well MW-40. The GWCL’s for these constituents are proposed to be set by methods acknowledging the increasing trends, 1.25 X background and 1.5 X background, respectively. Per DWMRC findings since most of the Report constituents for MW-38, MW-39
Page 7
and MW-40 are not demonstrating increasing trends, and since most GWCL’s are based on fractions of the groundwater quality standard, it is not anticipated that natural variation would
cause exceedances of the proposed GWCL’s and that if an exceedance of the proposed GWCL’s
does occur then compliance actions per the Permit would be warranted. Per the May 17, 2021 conference call, EFRI was concerned that constituent GWCL’s based on Mean + 2σ may exceed the GWCL and cause unnecessary accelerated monitoring of those constituents. EFRI was also concerned that natural conditions including dispersal of groundwater from the former
southern wildlife pond may cause reactions in the perched aquifer (oxidation of minerals) causing exceedances of constituent GWCL’s in the future. EFRI expressed that they would like DWMRC to review the upcoming submission of a geochemical study which is being submitted in response to ongoing investigation of out of compliance constituents at monitoring well MW-24, which is anticipated
to be expanded to a sitewide investigation, before making the decision to designate MW-38, MW-39,
and MW-40 as compliance monitoring wells. Per the call, DWMRC explained that the decision of whether to include MW-38, MW-39 and MW-40 as compliance monitoring wells or general monitoring wells would be delayed until modification of the Permit later in the year. Any information EFRI would submit before then will be considered by the
DWMRC. Conclusion:
Based on the DWMRC review of the Report, monitoring wells MW-38, MW-39 and MW-40 and semi-
annual monitoring frequencies will be included and formalized in the next Permit modification. Final decisions regarding the designation of the MW-38, MW-39 and MW-40 as compliance wells, or general monitoring wells, will be made based on current information at the time of Permit modification. Findings regarding the monitoring well designation will be included in the Permit modification Statement of Basis. This Permit modification will also include any changes required for the installation
of the proposed 5A and 5B tailings cells which is still currently under review. If you have any questions, please call Tom Rushing at [phone].
Sincerely,
Phil Goble, Uranium Mills and Radioactive Materials Section Manager Division of Waste Management and Radiation Control
PRG/TR/al c: Mike Moulton, Interim Health Officer, San Juan County Public Health Department
Ronnie Nieves, Environmental Director, San Juan County Public Health Department
Russell Seeley, UDEQ District Engineer