DRC-2014-001286 - 0901a068803fa874

State of Utah
GARY R HERBERT
Gove/710/-
SPENCER J COX
Lieutenant Governor
Department of
Environmental Quality
Amanda Smith
Executive Director
DIVISION OF RADIATION CONTROL
Rusty Lundberg
Director
DRC-201-001286
MEMORANDUM
TO:
THROUGH:
FROM:
DATE:
SUBJECT:
Summary
File M
Phil Goble, Compliance Section Manager
Tom Rushing, P.G. ^}Yi l/f/ldft
January 7, 2014
Energy Fuels Resources December 17, 2013 Source Assessment and Literature
Search Report, Tetrahydrofuran in Monitoring Well MW-1
The Source Assessment and Literature Search Report (SAR) for Tetrahydrofuran (THF) were
conducted by Energy Fuels Resources (USA) Inc. ("EFR") in response to a Utah Division of
Radiation Control ("DRC") Notice of Violation, Docket No. UGW13-05 ("NOV") issued on July
23, 2013. The NOV required EFR to submit a Plan and Time Schedule for investigation ofthe
THF exceedances within 30 calendar days of receipt of the NOV (Letter dated July 25, 2013).
A response to the NOV, which included a Plan and Time Schedule, was subsequently received by
DRC on August 27, 2013 and stated that EFR mistakenly assumed that the Source Assessment
Report requirements of the White Mesa Mill Ground Water Discharge Permit were not required
based on a DRC April 25, 2013 letter which agreed to remove Ground Water Compliance Limits
from monitoring well MW-1. EFR committed to submit a Source Assessment Report within 90
days from DRC Director Approval of the Plan and Time Schedule. The August 27, 2013 Plan and
Time schedule was approved by the Director on September 17, 2013. The SAR was subsequently
received on December 17, 2013 (via e-mail) and includes a source assessment review for THF as
well as document review summaries for THF sources related to well construction using Schedule
40 Polyvinyl Chloride (PVC) casing coupled with solvent and adhesive.
THF was studied under the EFR category as other constituents since no previously identified THF
trends have been noted.
Potential Sources of THF in Up2radient Well MW-1
Tailings Cells:
195 North 1950 West • Salt Lake City, UT
Mailing Address P O Box 144850 • Salt Lake City, UT 84114-4850
Telephone [phone] • Fax [phone] • T D D [phone]
www deq utah gov
Pnnted on 100% recycled paper
EFR Tetrahydrofuran Source Assessment and Literature Search Report
Page 2
The tailings cells were eliminated as a source of the THF at monitoring well MW-1. The SAR
points out that the tailings solutions contains THF, likely caused by Grignard reactions with
Kerosene produced during manufacturing process (refinery kerosene synthesis and/or blending
process), but eliminates this source based on monitoring well MW-1 being located 2,200 feet
upgradient ofthe tailings cells (nearest tailings cell location) and measured groundwater elevation
at monitoring well MW-1 being 9 feet higher than groundwater elevation under the tailings cells
(nearest location to monitoring well MW-1).
Monitoring Well Construction and Materials:
Well MW-1 was constructed in 1979 using Schedule 40 Polyvinyl Chloride (PVC) coupled with
solvent and adhesive. PVC cements contain THF as a softening agent and carrier for glue
monomer components. The SAR notes that THF has a low Henry's Constant which indicates low
volatilization and that glue on the PVC joint will have a residual of THF. Additionally, the PVC
casing material may be subject to deterioration and potential dissolution of organic constituents to
groundwater.
EFR determined in the SAR that the most likely source of THF in groundwater samples is from
the PVC joint glues. Fluctuating ground water levels would provide for intermittent contact of
groundwater with the PVC joints and glue residuals and could leach THF into the ground water.
EFR provides literature review to support this claim as discussed in the "EFR Literature Review"
section below.
To explain why THF detection is different at various site monitoring wells, EFR notes that the
groundwater monitoring wells were constructed by varying personnel and that those different
personnel may have used differing amounts of glue for well construction (Some wells may have
more prevalence of THF leaching due to the use of more glue). Additionally, some batches of
glue may have had more solvent making leaching of THF more likely at certain wells. Ambient
temperature and humidity may have additionally been different during construction ofthe various
monitoring wells and may have caused certain wells to cure at a slower rate.
EFR Literature Review
The SAR includes a summary of three different literature sources which were reviewed to support
the claim that monitoring well glues and solvents, used during well construction could be the
source of THF at monitoring well MW-1. DRC staff additionally reviewed each ofthe
summarized literature sources to support the EFR claims. A discussion of each of the literature
source findings is below:
1. William Martin and C. Chow Lee, 1989: EFR review of Martin and Lee confirmed that in
the case of THF contamination due to well joint glues the concentrations will persist for
extended periods of time. The SAR quotes the Martin and Lee referenced p. 211 as
follows: "The further increase in THF concentration 2 to~4 days after purging suggests
that THF may be rapidly diffusing from the PVC glued joints into fresh formation water
entering the well." DRC further notes that these effects may last for extended periods of
time after well construction as noted on p. 214 "As these investigations have shown (At
EFR Tetrahydrofuran Source Assessment and Literature Search Report
Page 3
least for cement grout and THF contamination) anomalies attributable to well
construction can persist for many years, if not for the lifetime of the monitoring well
despite repeated development and monitoring." Martin and Lee reported groundwater
leached concentrations of 460ug/L at 20 days after monitoring well construction.
Martin and Lee supports the EFR claim that the THF source in monitoring well MW-1 is
potentially from glues used during well construction. Analytical results for THF in
monitoring well MW-1 are not far outside of concentrations observed by Martin and Lee
20 days after monitoring well construction.
2. United States Geological Survey, 1995: Reference discusses ground water monitoring
well materials, design, and installation and interferences that occur based on materials and
design. Sections of the reference discuss specific PVC well casing glues and biases that
occur in analysis for volatile organic contaminants including THF (and MEK, MIBK and
hexanone).
3. United States Geological Survey, 2012: THF concentrations detected in monitoring well
samples cannot be attributed to aquifer concentrations due to potential contamination from
organic constituents in joint glue and/or decontamination procedures of sampling
equipment at the Study Reporting Limits.
Conclusions
EFR Conclusions:
Based on DRC staff review of the EFR THF Report and review of the cited literature sources,
EFR concludes that THF well MW-1 is not due to impact from Mill discharges as supported by
EFR findings discussed above and as summarized in the bullet statements below:
• Measured groundwater elevation at monitoring well MW-1 is approximately 9 feet higher
than the groundwater elevation measured at upgradient portions of the Mill tailings cells,
• MW-1 is approximately 0.4 miles up gradient of the Mill facilities,
• Per literature review it is likely that the THF concentrations are the result of well
construction practices (PVC and joint adhesive) and rising groundwater levels at the
monitoring well location. Per literature review, organic compounds including THF can
persist for extended periods of time [may persist for the lifetime of the well (William
Martin and C. Chow Lee, 1989)].
EFR Continued Actions:
• EFR will continue to monitor THF in MW-1 quarterly beginning from the third quarter of
2013,
• EFR will re-evaluate the status of THF in the well after three additional quarters of
accelerated data have been collected/analyzed with discussion of the results to be included
with the White Mesa Mill 2nd Quarter 2014 Groundwater Monitoring Report. EFR
additionally states that "if the levels remain below the GWCL during the four quarters
EFR Tetrahydrofuran Source Assessment and Literature Search Report
Page 4
ending the second quarter of 2014, EFRIwill resume semi-annual monitoring of MW-1 for
THF. If THF exceeds the GWCL during these four quarters, EFRIwill continue
accelerated (quarterly) monitoring for THF in MW-1 until removal of the GWCL occurs
with the publication of the revised GWDPT
DRC Findings/Conclusions based on Review of the SAR:
DRC concurs that based on the location, respective groundwater gradients (upgradient well MW-1
and tailings cells) and measured groundwater elevations it is unlikely that the source of the THF is
due to tailings solution leakage or other mill related activities.
Additionally, based on DRC review of the literature sources it appears that PVC solvents and
glues are a feasible source for the THF in the groundwater at monitoring well MW-1 (based on
well construction technique). DRC notes that per the literature, PVC solvents and glues may
leach organic constituents including THF into groundwater for years after well installation and
potentially for the life of the monitoring well. Literature source, USGS 2012, additionally
provided examples of monitoring well studies which show that THF concentrations in
groundwater, due to leaching of organic constituents from PVC glues, can be much higher than
concentrations measured in EFR monitoring well MW-1.
DRC does not agree with the EFR conclusion to automatically return monitoring well MW-1 to
baseline frequency based on the EFR re-evaluation, as stated by EFR in the SAR. DRC noted that
the planned approach will not provide at least eight accelerated samples with results below the
GWCL (Per DRC review ofthe 3rd Quarter 2013 Ground Water Monitoring Report).
Accelerated monitoring of THF in monitoring well MW-1 may be discontinued and returned to
baseline semi-annual monitoring only if:
1. EFR submits a request to the Director to return MW-1 to baseline monitoring which
includes at least eight groundwater sample results for THF below Ground Water
Compliance Limits listed in the Permit and the EFR request is subsequently approved, or,
2. GWCL's for monitoring well MW-1 are removed from the Permit by authorization by the
Director (Permit Modification) after public hearing and comments have been received and
addressed.
References
Martin, William H. and C. Chow Lee Persistent pH and Tetrahydrofuran Anomalies Attributable
to Well Construction. Woodward-Clyde Consultants, Oakland, California 1989.
U.S. Geological Survey. Open File Report 95-398 Ground-water Date-Collection Protocols and
Procedures for the National Water-Quality Assessment Program: Selection, Installation,
and Documentation of Wells, and Collection of Related Data. 1995.
U.S. Geological Survey. Scientific Investigations Report Evaluation of Volatile Organic
Compound (VOC) Blank Data and Application of Study Reporting Levels to
EFR Tetrahydrofuran Source Assessment and Literature Search Report
Page 5
Groundwater Data Collected for the California GAMA Priority Basin Project, May 2004
through September 2010 Pub. 2012.