DRC-2020-010104 - 0901a06880c8ac4c

DRC-2020-010104 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
GARY R. HERBERT Governor SPENCER J. COX Lieutenant Governor
Department of Environmental Quality
L. Scott Baird Executive Director DIVISION OF WASTE MANAGEMENT AND RADIATION CONTROL Ty L. Howard Director

May 27, 2020

Kathy Weinel, Quality Assurance Manager Energy Fuels Resources (USA) Inc. 225 Union Blvd., Suite 600
Lakewood, CO 80228
RE: Request for Additional Information (RAI) regarding the Energy Fuels Resources, May 8, 2020 White Mesa Uranium Mill Low Flow Sampling Plan Utah Groundwater Discharge Permit No. UGW370004

Dear Ms. Weinel: The Division of Waste Management and Radiation Control (DWMRC) has reviewed the Energy Fuels Resources (USA) Inc. May 8, 2020 White Mesa Uranium Mill Low Flow Sampling Plan (EFR Plan).
Based on review, the DWMRC is requesting additional information as discussed below.
RAI – Cited Low Flow Guidance in the EFR Plan needs to be Updated and Discussed The EFR Plan cites three references regarding low flow sampling including: 1) Low Flow (Minimal
Drawdown) Groundwater Sampling (Puls and Barcelona 1996); 2) Groundwater Sampling Guidelines
for Superfund and RCRA Project Managers (Yeskis and Zavala 2002); and 3) EQASOP-GW4, Region 1
Low Stress (Low Flow) SOP Rev 4 (EPA 2017). The EFR Plan states that these guidance references limit the use of low flow sampling to monitoring wells with screen lengths less than 10 feet and inside diameters 1.5 inches and greater. Per DWMRC review of the EPA 2017 SOP it was noted that the
criteria cite the Puls and Barcelona 1996 guidance, which was an EPA contracted study. Therefore, the
EPA 2017 SOP is limited to the 1996 findings and, per DWMRC review, additional study was conducted after the 1996 guidance which updated those findings and found that low flow sampling is appropriate and representative of longer well screen lengths.
Specifically, M.J. Barcelona, M.D. Varljen, R.W. Puls and D. Kaminski, Winter 2005, Ground Water
Purging and Sampling Methods: History vs. Hysteria, Ground Water Monitoring & Remediation 25, no. 1/pp 52-62 states that monitoring wells should not be prohibited from low flow sampling based on well screen lengths alone. (Over)

The use of low flow monitoring and representativeness in the case of longer well screens is based on a site and/or well basis. Therefore, an objective of the EFR Plan and study is to determine the suitability
of the White Mesa monitoring well designs and aquifer properties for low flow sampling.
This evaluation is needed based on the erroneous (high) dissolved oxygen readings at several monitoring wells and, as was noted in the EFR Plan, the current groundwater purge collection is likely introducing air into samples based on the fully penetrating well screens, perched aquifer hydraulic properties, and
small saturated thickness at several wells, which results in significant agitation of the groundwater
sample at affected monitoring wells. Low flow sampling comparisons with standard purge samples should provide more information regarding the reliability of monitoring results in the event of sample agitation/aeration during purging. Specifically, sample comparison will be used to determine whether the sample agitation affects data results.

Please modify the discussion of literature citations to include more recent studies of low flow purge and appropriate screened intervals based on the data results. Again, all conclusions regarding the appropriateness of the low flow method for monitoring wells at the White Mesa Mill should be based on the Mill specific sampling and data evaluation. The objective of the low flow monitoring study is to
evaluate whether there are data impacts due to sample aeration during standard (2 casing volume)
purging activities. RAI – EFR Plan Well Set Needs to be Expanded and Representative of Mill Groundwater
The EFR Plan states that the three upgradient monitoring wells MW-01, MW-18 and MW-19 will be
used for the study. The EFR Plan states that these wells are appropriate for the study based on “a wide
range of both hydraulic conductivities and DO results.” Per DWMRC review, this small well set does not represent sitewide monitoring wells and does not adequately address issues where DO measurements greater than 100% were found.

Please modify the well set to include a representation of sitewide monitoring wells, including the compliance well monitoring wells where significant agitation/oxygenation of groundwater samples was found (>10% DO). Per the discussion between DWMRC, EFR and Hydro Geo Chem on May 18, 2020 it was decided that a set of 10 monitoring wells or more is adequate to address the study objectives.
EFR discussed that the wells would be evaluated to determine which ones show relatively high DO
measurements and have local aquifer hydraulic properties favorable to low flow purging parameters (e.g. will not be susceptible to excessive drawdown). Samples by Both Methods need to be Collected at the Same Time for Data Comparison

Evaluation of the monitoring results will require the comparison of analytical data (all field, compliance and background constituents) between the two collection procedures (low flow and standard 2 casing volume purge). In order to provide comparable data, the samples by each method will need to be collected at the same time (low flow sample followed by purge sample). The current method included in
the EFR Plan is not acceptable for this purpose. The EFR Plan states that the three upgradient
monitoring wells listed above will be used for the study and will be collected by the different purge methods during completely different quarterly sampling. Specifically, the EFR Plan outlines a method of collecting purge samples during the compliance quarters (Semi-Annual Sampling is required at the

Upgradient Wells by the Groundwater Permit), and low flow samples during the other quarters. This will not provide comparable results.

Based on the expanded monitoring well set discussed in the RAI above, please include a plan for sample collection by low flow and standard purge (2 volume) at the same time (collected contiguously). EFR Data Summary and Evaluation Clarification Needed

The EFR Plan only includes a statement that data will be summarized in a final report (EFR Plan 9.0). Please include a discussion in this section generally presenting how the data will be evaluated, summarized, and submitted by EFR.
These issues were discussed in a conference call amongst DWMRC, EFR and Hydro Geo Chem on
May 18, 2020. Per the discussion, the EFR Plan will be updated and resubmitted on or before July 20, 2020. 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: Kirk Benge, Health Officer, San Juan Public Health Department
Rick Meyer, Environmental Health Director, San Juan Public Health Department Russell Seeley, UDEQ District Engineer