DRC-2021-004242 - 0901a06880e4e7e4

DRC-2021-004242 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 Ty L. Howard Director

March 31, 2021
Kathy Weinel, Quality Assurance Manager
Energy Fuels Resources (USA) Inc.
225 Union Blvd., Suite 600 Lakewood, CO 80228 RE: Energy Fuels Resources, White Mesa Uranium Mill February 17, 2021, 4th Quarter 2020 Groundwater Monitoring Report, January 25, 2021 Notice Pursuant to Part I.G.1(a)., and,
Monitoring Well MW-24/MW-24A Data Review and Additional Source Assessment Utah Groundwater Discharge Permit No. UGW370004 Dear Ms. Weinel:

The Division of Waste Management and Radiation Control (DWMRC) has completed review of the following Energy Fuels Resources (USA) Inc. (EFR) documents: 1. EFR, February 17, 2021, Transmittal of 4th Quarter 2020 Groundwater Monitoring Report Groundwater Quality Discharge Permit UGW370004 White Mesa Uranium Mill (Received
by DWMRC on February 19, 2021). 2. EFR, January 25, 2021, State of Utah Ground Water Discharge Permit No. UGW370004 White Mesa Uranium Mill – Notice Pursuant to Part I.G.1(a).
The review was conducted to ensure compliance with all applicable parts of Utah Groundwater Discharge Permit No. UGW370004 (Permit) issued for the White Mesa Uranium Mill located in Blanding, Utah.
DWMRC has additionally reviewed the data for groundwater monitoring wells MW-24/MW-24A and is
providing an update to address continued source assessment for out-of-compliance (OOC) constituents in monitoring well MW-24. As noted, continued accelerated monitoring and additional source assessment and monitoring locations are needed for assessment. (Over)

EFR 4th Quarter 2020 Groundwater Monitoring Report Close-out:

Based on review of the EFR February 17, 2021 4th Quarter 2020 Groundwater Monitoring Report, it appears that all applicable requirements of the Permit were met. Therefore, the review is hereby closed out. EFR Notice Pursuant to Part I.G.1(a) – Close-out:
Based on review of the EFR January 25, 2021 Notice it appears that all requirements of the Permit were met. Therefore, the review is hereby closed out.
Monitoring Wells MW-24/MW-24A, Evaluation of Groundwater Monitoring Data and Source Assessment of MW-24 Out-of-Compliance Parameters – Findings and Additional Source Assessment: Per review of the EFR June 27, 2019 Source Assessment Report for OOC constituents in monitoring well MW-24 (Beryllium, Cadmium, Nickel, Thallium, Fluoride, pH), DWMRC noted that beryllium and
nickel had recent increasing trends which were previously non-detect. Although, per DWMRC review of the source assessment, it was agreed that the recent MW-24 data trends did not appear to be caused by a tailings wastewater source, it was also agreed that the GWCL exceedances warranted additional investigation given their sudden and significant appearance. The DWMRC findings were discussed
during a September 3, 2019 conference call and it was decided that additional assessment would be
conducted to determine if MW-24 well construction was the cause of the exceedances and trends. Monitoring well MW-24A was subsequently installed to determine if well construction was the cause. Per DWMRC review of the 1st and 2nd Quarter 2020 Monitoring Data at MW-24A, it was noted that the same OOC monitoring constituents showed elevated concentrations as observed in MW-24 groundwater
data. The monitoring results confirmed that the exceedances at MW-24 were not caused by well construction problems since the same data pattern of constituent exceedances and high concentrations were evident.
Based on review of the EFR 2nd Quarter Groundwater Monitoring Report, it was found appropriate to
collect additional MW-24/MW-24A tandem samples for comparison and better evaluation of indicator parameters and heavy metals: 1. Additional quarterly pH, sulfate, and chloride data points at MW-24/MW-24A to provide more information of concentrations and trends. Two additional quarterly samples will provide an
additional full year including potential seasonal variation. 2. Additional data for other heavy metals (beryllium, cadmium, manganese, nickel, and thallium) to evaluate the degree (steepness of curve) of upward concentration trends.
It was additionally noted that based on current groundwater monitoring data and trends it may be
appropriate for EFR to consider additional information and data points (e.g., new monitoring wells) to evaluate the observed concentrations in MW-24 and MW-24A. It is noted that groundwater concentrations of nearby and downgradient monitoring well MW-02 are not currently indicating the same exceedances or trends. However, additional data at point(s) downgradient and near MW-24/MW-24A would be useful to better evaluate the exceedances and potential source. It is also noted that

chloride concentrations at MW-24 are low and are not trending upward as would be expected if the
OOC were caused by solution from Cell 1.
Per review of the 4th Quarter 2020 Groundwater Monitoring data, it is noted that the additional data points have been collected to provide a full year of comparable data and trends. Per data review of the 3rd and 4th Quarter OOC parameters, data for MW-24/MW-24A continue to show significant increasing trends. Although the primary indicator parameter for a tailings solution source, chloride, is not showing
increases. In a telephone conference call between DWMRC and EFR on March 29, 2021 it was discussed that additional source assessment for OOC parameters and trends at MW-24 is needed. Per the telephone
discussion, EFR will propose actions for the continuing source assessment. Based on the continued
OOC and ongoing needed source evaluation, the GWCL’s will remain at current concentrations and accelerated monitoring will continue. If you have any questions, please call Tom Rushing at [phone].
Sincerely,
Phil Goble, Uranium Mills and Radioactive Materials Manager
Division of Waste Management and Radiation Control PRG/TR/as 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