DRC-2017-001146 - 0901a068806b3bdc

State of Utah
GARY R. HERBERT Governor SPENCER J. COX
Lieutenant Governor
Department of
Environmental Quality
Alan Matheson Executive Director DIVISION OF WASTE MANAGEMENT AND RADIATION CONTROL Scott T. Anderson Director

February 16, 2017

Scott Clow, Environmental Programs Director
Ute Mountain Ute Tribe
Environmental Programs Department
P.O. Box 448 Towaoc, CO 81334-0448

RE: Response to Ute Mountain Ute Tribe Letters Dated December 16, 2016 and January 20, 2017

Dear Mr. Clow:
This letter is in response to two letters from the Ute Mountain Ute Tribe dated December 16, 2016 and
January 20, 2017. The letters were received by the Division of Waste Management and Radiation
Control on December 20, 2016 and January 25, 2017 respectively. The letters the Tribe’s concerns
regarding three issues:
1. The plugging and abandonment of monitoring well MW-3 at the White Mesa Uranium
Mill (Mill);
2. The adjustment of cadmium and thallium groundwater compliance limits (GWCLs) in the
Mill Groundwater Discharge Permit, Permit No. UGW370004 (Permit); and 3. The Ute Mountain Ute Tribe’s efforts to gain access for Duke University representatives
to collect water samples from several of the Mill monitoring wells.

Each of these concerns is discussed below.
Plugging and Abandonment of Monitoring Well MW-3

A 2005 Permit Statement of Basis listed several construction issues associated with monitoring well
MW-3. At that time, it was decided that a replacement well should be installed and the Permit
subsequently included a requirement to install the replacement monitoring well. The Permittee installed monitoring well MW-3A as a replacement for MW-3 during August 2005.
Specific issues concerning Monitoring Well MW-3 construction were:

DRC-2017-001146 195 North 1950 West • Salt Lake City, UT Mailing Address: P.O. Box 144880 • Salt Lake City, UT 84114-4880
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1. No geologic log was available for Monitoring Well MW-3 and it was is not possible to verify whether the screened interval was located at the base of the Brushy Basin Shallow
Aquifer.
2. MW-3 was constructed without a filter media or sand pack across the screened interval.
3. A 10-foot long section of blank (non-perforated) casing was left at the bottom of the
monitoring well below the screened interval which acted as a sump and contained stagnant water and sediment.
4. MW-3 was a low yield well. Water levels were typically only five feet above the base of
the well screen.

These construction issues, low water levels and low recharge rates in the well have caused inconsistent results for several of the monitoring constituents. It is noted that both monitoring wells, MW-3 and
MW-3A, have been monitored by the Energy Fuels Resources since the installation of monitoring well
MW-3A (11 years of data for both wells). The two wells are located in close proximity to each other
and MW-3A does not show the same inconsistent results or elevated concentrations, supporting the
finding that the MW-3 well construction has been the historical cause of fluctuating results and has likely resulted in GWCL exceedances of several monitoring parameters.

Based on these findings, it was determined by the Director that continued monitoring of MW-3 was not
warranted, that the well was producing erroneous and misleading results and that the well should be
plugged and abandoned in conformance with State rules and regulations, as was intended during the 2005 review for the Statement of Basis. Well abandonment activities were completed on
November 30, 2016 by Bayles Exploration Inc., a licensed water well driller, under the direction of a
Utah licensed professional geologist (Stewart J. Smith) with Hydro Geo Chem. Inc.

In accordance with the Division’s evaluation of the GWCLs at the replacement monitoring well MW-3A, it was requested by the Tribe that Energy Fuels Resources provide revised statistical analysis for
cadmium and manganese. Based on a review of the revised statistics provided by Energy Fuels
Resources, the GWCLs will be lowered in the Permit renewal for these monitoring parameters to reflect
current data results.
Cadmium and Thallium in Monitoring Well MW-24

A Division review of a June 24, 2016 Source Assessment Report (Source Assessment) prepared by
Energy Fuels Resources regarding out-of-compliance parameters in monitoring well MW-24, including
cadmium and thallium, documented that Mill Activities did not appear to be the cause of exceedances. This finding was supported by clear lines of evidence in the Source Assessment. It its January 20, 2017
letter, it appears that the Tribe feels that the lines of evidence used in the Source Assessment were not
supported. The lines of evidence discussed by the Tribe and Division responses to the concerns are
below:

• The Tribe offered this comment. “The first reason cited ‘a review of indicator parameters
concentration trends’ fails to account for the intent of the 2004 Statement of Basis for the initial
GWDP. Technical analysis performed by DWMRC for the GWDP led to the selection of 38 specific indicator parameters which were selected because of multiple factors: feedstock materials, process reagents, source term abundance and contaminant mobility. The intent of selecting 38 specific parameters for analysis in the POC well system is to serve as an early
warning indicator of groundwater pollution. Under this approach, compliance is determined in
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each well and for each parameter Under the GWDP contamination may be indicated and regulated based on a determination of significance for any of the 38 indicator parameters.”

In accordance with the 2004 Statement of Basis, the 38 parameters were included in the Permit
as groundwater compliance monitoring parameters based on average concentrations in tailings
wastewater from the sources listed in the Tribe comment. In no part of the Statement of Basis are these metals referred to as indicator parameters. Parameters which are selected as early
indicators of tailings solution in groundwater consider both the concentration in the source and
the mobility of the contaminant if released from the source. This is consideration of the
contaminant to partition on aquifer materials as determined by the development of partitioning
coefficients (Kd) and retardation factors (Rf).
The Division notes that, in regards to chloride and sulfate, there is no retardation of movement
through the vadose zone. As noted in the 2004 Statement of Basis, average concentrations of
chloride and sulfate in tailings wastewater at that time were 4,608 mg/L and 64,913 mg/L
respectively. These parameters are highly concentrated in the tailings wastewater and are highly mobile and thus will be the earliest reliable indicators of tailings solution at the
groundwater monitoring wells.

Fluoride is another non-reactive, highly mobile contaminant which is highly abundant in the
tailings solution and will be transported to the monitoring wells relatively rapidly. As indicated in the 2004 Statement of Basis, an average fluoride concentration in tailings wastewater was
1,694 mg/L.

In terms of average metals concentrations in tailings wastewater, uranium has much higher
concentrations than cadmium or thallium. Average uranium concentration in tailings wastewater was 93.6 mg/L vs. concentrations of cadmium (3.4 mg/L) and thallium (16 mg/L). Additionally, uranium is much more mobile than either cadmium or thallium making uranium a
better early indicator of tailings cell leakage in the groundwater.

The Division is concerned about the Tribe’s recent use of gross average trace metals concentrations in groundwater to claim that a contaminant plume exists below the Mill. Specifically, these claims have been made in the Tribe’s Report prepared by Geo-Logic
Associates.1 The Geo Logic Report does not consider the concentrations of specific metals in
the tailings cells, the relative mobility of contaminants, established background concentrations
for each well, state ground water quality standards or ground water compliance limits. Additionally, the Geo-Logic Report groups data from several wells and interprets the data in a
highly biased and completely unrepresentative manner.

• According to the Tribe, the second line of evidence used by the Division to eliminate tailings solution as the cause of increases of cadmium and thallium increasing concentration in
1 Geo-Logic Associates, August 2015, Data Review and Evaluation of Groundwater Monitoring White Mesa Uranium Mill
Blanding Utah, Prepared for the Ute Mountain Ute Tribe

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groundwater, the 2007/2008 University of Utah Study (Study)2, is not considered valid. As stated in the Tribe’s January 20, 2017 letter, the Study “is older than the observed changes of
water chemistry in well MW-24 (cadmium and thallium increases dramatically starting in
2009). MW-24 was not included in the University of Utah Study, and cadmium and thallium
were not among the trace metals sampled in any of the wells that were sampled during that study.” Additionally, the Tribe does not consider specific conclusions in the Study regarding monitoring well MW-2 applicable for evaluation of MW-24, since MW-2 is not showing rising
concentration for cadmium and thallium.

The Division notes that monitoring well MW-2 is located approximately 200 meters from MW-
24 and is directly hydraulically downgradient from MW-24 according to the current kriged water levels and contour map. Based on this, the Division does see MW-2 as a good
comparison for MW-24. Samples collected at MW-2 for tritium, nitrate, sulfate, deuterium,
uranium, manganese, selenium, CFCs and helium oxygen and sulfur stable isotopes showed
that the water in MW-2 predated the Mill and was not impacted by tailings cell leakage.
In response to the Tribe’s comments regarding the change of water quality, which occurred in
2009, these changes were likely due to the Energy Fuels Resources activities to re-
develop/over-pump all of the monitoring wells at the Mill in order to address turbidity issues at
some of the wells, and appears to have affected concentrations of metals and pH as a result.
These activities and chemistry changes have not altered the validity of the Study and its usefulness as a line of evidence when conducting source assessments.

In accordance with the Study, it was recommended that some of the sampling techniques and
information used in the Study may be useful for future monitoring to potentially detect early
indication of a tailing cell leak, specifically, sampling for sulfur isotopes and comparing those with the isotopic signature in the tailings cell solutions. The Study indicates that this
comparison may allow the detection of approximately 1% of tailings solution in the
groundwater which is a much lower relative percentage tailings solution than would be needed
for detection by metals and inorganic ions alone. The Study also recommends continued
sampling of trace metals and inorganic ions which is currently ongoing as required by the Permit.

The Study used uranium, manganese and selenium as indicators of tailings solution in the
groundwater (did not include cadmium and thallium) in association with evidence that the
groundwater sampled was determined to be young water. This method was used to differentiate metals concentrations associated with a solute source vs. an aquifer source based on age dating
of the groundwater sampled, not as a stand-alone method. As discussed above, when using
specific analytes to detect early releases of tailings solution, it is most useful to use analytes
with high abundance in the tailings solution and those which are more mobile. This was the
basis for the University of Utah trace metals selections.
2 Hurst, T.G., and Solomon, D.K. University of Utah, 2008, Summary of Work Completed, data Results, Interpretations and Recommendations for the July 2007 Sampling Event at the Denison Mines, USA White Mesa Uranium Mill Near Blanding,
Utah, Prepared by Department of Geology and Geophysics.

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Energy Fuels Resources also discusses a relationship between cadmium and thallium concentrations in MW-24 and a potential geochemical relation between the well redevelopment
activities in 2009, which introduced oxygen in zones around the monitoring well screen and
may have oxidized pyrite within those zones. This would cause a decrease in pH concentration,
which has been occurring, and subsequent rise in the concentration of metals in solution
according to the local mineral matrix in the rock. The Division agreed that this could be a potential cause for the decreasing pH trends noted at monitoring wells above the facility, at the
facility and far downgradient from the facility. Energy Fuels Resources prepared a report
studying the possibility of this situation, the “Pyrite Investigation Report” dated
December 7, 20123 (Pyrite Report).
The Tribe’s January 20, 2017 letter states, “To date, there is no scientific evidence that proves
pyrite oxidation in the Burro Canyon Formation is causing pH declines. Numerous scientific
reports document that the unconfined Burro Canyon Formation has been oxygenated for a long
period of geologic time. Testing by EFRI consultants during the course of the pyrite investigation support that the formation has been oxidized, but there was no pyrite detected by X Ray Diffraction analysis for any of the samples collected from the vadose zone. At a
minimum further investigation and testing regarding the validity of the pyrite theory need to be
conducted immediately, and solid scientific evidence should be presented/reviewed and
approved prior to using this theory to raise compliance limits for indicator parameters of tailings cell solutions.”
The Pyrite Report documents that pyrite was detected by X-Ray Diffraction in samples from
MW-3A, MW-24, MW-26, MW-27, MW-28 and MW-32 at concentrations ranging from 0.1%
to 0.8% by weight. The percentage of pyrite found in the core samples MW-24 core was 0.08
% Fe2O3 which corresponds to 0.8 g/Kg of the formation. The pH decreases in monitoring well MW-24 are discussed in Section 4.3.2.2 of the Pyrite Report which includes a discussion of
geochemical modeling results.

Although pyrite dissolution is considered a potential mechanism for the reductions in pH and
rise in metals concentrations at several monitoring wells, including MW-24, this is not a primary basis that the Division is using to adjust GWCLs. The results of the Pyrite Study and
Report showed a possible mechanism and explanation for the site-wide pH decreases. This
may be a reasonable explanation given that oxygen was introduced at the well screen at the
same time as pH decreases began (2009). This also may be an explanation as to why pH
decreases are more pronounced at some wells more than others since available pyrite in the saturated zone is different for each monitoring well.
The Tribe additionally states “The fourth and final reason cited is ‘potential analytical
influences caused by and EFR change in laboratories during the fourth quarter of 2012.’ Rising trends for cadmium and thallium were noted in 2009 and continue today, pH continues to decline, and fluoride levels continue to rise. The laboratory change is irrelevant to the discussion of source identification of pollutants in MW-24.”

3 Energy Fuels Resources (USA) Inc., December 7, 2012, Pyrite Investigation Report, Prepared by HYDRO GEO CHEM,
INC.

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According to the Energy Fuels Resources June 4, 2016 Source Assessment Report for MW-244 (Source Assessment) Part 3.1.4, the analytical laboratory change during 2012 may have caused
additional variability in the data, especially in the case of fluoride. The Source Assessment
does not, however, claim that the change in laboratory is the cause of exceedances and is not
used as part of the source assessment. The Division did not review the change in laboratories as
a cause for GWPL exceedances or rising trends and is unsure why the Tribe made this comment.

Ute Mountain Ute Tribe – Duke University Study

Both of the Tribe’s letters reference a project that is being coordinated between the Tribe and the Duke University Nicholas School of the Environment. According to the letters, this action is being conducted
by the Tribe based on discussion during a meeting between the Division and the Tribe on August 9,
2016. The discussion at that meeting was regarding the University of Utah Study and whether the
conclusions in that report were still valid. The Tribe specifically raised concerns that the University of
Utah Study was conducted in 2007/2008 and that revisiting the study procedures, to obtain evidence of groundwater age and isotopic signatures of groundwater should be considered.

The University of Utah study conclusions provided recommendations for future isotopic sampling and
analysis which may provide earlier detection of tailings solution in groundwater than would be detected
by routine monitoring for trace metals and anions. These recommendations are discussed in the second bullet item above.

The Tribe additionally stated in its letters that “Nancy Lauer (Duke University Graduate Student)
planned a sampling trip in November 2016 and coordinated with the Tribe to collect nine samples from our two monitoring wells, a community supply well in the community of White Mesa, four springs around White Mesa and Recapture Reservoir which is the source of part of the process water EFRI uses.
Nancy Lauer also attempted to coordinate with EFRI for access to the facility in order to sample on site
wells however permission was denied and we understand that EFRI would not allow access unless they
were compelled by UDWMRC.”
Please note that the Division was not aware of the sampling trip planned for November 2016 or provided
information regarding the Duke University study or its scope. As discussed above, the previous
University of Utah study provided an evaluation of surface waters (Recapture Reservoir, Wildlife Ponds
and Tailings Wastewater Solution) and recommended specific isotopic sampling which would be
valuable tracers to identify sources of “young” water in the groundwater monitoring wells. It is unclear to the Division if the intention of Duke University is to provide a continued verification that tailings
wastewater is not present in the monitoring wells or if the Study has a different objective.

The Division has not been provided an understanding of what sampling is being proposed and conducted
by Duke University, how samples will be collected and analyzed, or quality assurance standards which will be used to ensure validity of the sample results and conclusions. The Tribe letters include a website
link, http://sites.nicholas.duke.edu/avnervengosh/. However, the Division discovered that this website is
4 Energy Fuels Resources (USA) Inc., June 24, 2016, Source Assessment Report for MW-18 and MW-24, White Mesa Mill
Prepared by Intera

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a biography of Dr. Avner Vengosh (Duke University Professor) and summarizes some of his projects. The website does not provide any details regarding a proposed project at the White Mesa Uranium Mill.

It is also not clear to the Division if the samples collected by Nancy Lauer (Duke University) at the
locations stated by the Tribe have been analyzed or if the Tribe has received results of those samples or
been advised of findings related to the sample results. If it is the intention of the Tribe to potentially coordinate a project at the White Mesa Mill, then communication regarding the project scope and goals
and specifics regarding monitoring parameters and quality control needs to be undertaken. Additionally,
the previous study and report prepared by the University of Utah should be acknowledged and cited as
part of any additional ongoing investigation.
Please provide the Duke University Project Plan and Scope so the Division can review and discuss this
proposal. Additionally, it would be helpful to receive the results of Nancy Lauer’s November 2016
sampling trip if available.

If you have any questions, please call Tom Rushing at [phone].
Sincerely,

Scott T. Anderson, Director
Division of Waste Management and Radiation Control

STA/TR/ka
c: Rick Meyer, Acting, Health Officer/Environmental Health Director, San Juan Public Health
Scott Hacking, P.E., UDEQ District Engineer
Treasure Bailley, USEPA Region 8