DRC-2018-007250 - 0901a0688087e0c6

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
MEMORANDUM ÐRC-2M -DOUSD
FR,‘ /01s7
FROM: Tom Rushing, P.G. Vje 1- 11-
DATE: July 17, 2018
SUBJECT: Review of the Energy Fuels Resources (USA) Inc. (EFR), White Mesa Uranium Mill,
Blanding, Utah June 25, 2018 Source Assessment Report for Fluoride in Monitoring Well
MW-14, Ground Water Discharge Permit UGW370004
Summary
A Source Assessment Report (SAR) for Fluoride in Monitoring Well MW-14 at the EFR White Mesa
Uranium Mill (Mill), dated June 25, 2018 was received by the Division of Waste Management and
Radiation Control (DWMRC) on June 27, 2018. The SAR was submitted for Director review and approval
of a proposed revised Ground Water Compliance Limit (GWCL). The SAR was submitted in accordance
with a previously submitted EFR Plan and Time Schedule dated March 2, 2018. Monitoring well MW-14
is located on the southern berm of the Mill Tailings Cell 4A and is hydraulically downgradient from
eastern portions of Cell 4A and from the Mill processing areas.
The SAR is broken up into four primary sections, 1. The approach for analysis of potential sources of the
contamination, 2. Results of the analysis, 3. Statistical evaluation and calculation of a revised GWCL, and,
4. Conclusions and recommendations. Generally, the SAR uses evidence from the 2007 University of Utah
groundwater study and indicator parameter analysis to substantiate that the out of compliance status was
not caused by Mill activities. The SAR further discusses a change in laboratory and fluoride laboratory
method in 2012 which likely caused high fluoride results due to sample matrix interferences. A discussion
of the EFR communication with the laboratory is included in the SAR.
The DWMRC time series plots below depict the decreasing or essentially flat concentration trends in
monitoring well MW-14 for fluoride and primary indicator parameters Cl, SO4 and U using all available
historical data (including potential outliers). A plot is also included for pH which shows an essentially flat
trend.
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EFR June 25, 2018 MW-14 Source Assessment Report
DWMRC Review Memo
Page 2
Figure 1 — Fluoride Data Plot of Historical Data at MW-14 — Decreasing Trend
MW-14 Fl mg/I.
•
wow N. mo •111.1
— on. (Mr m A.%)

Figure 2- Chloride Data Plot of Historical Data at MW-14 — No Trend
MW-14 CI
• +mug
,—twalmve A4,1i
Figure — Sulfate Data Plot of Historical Data at MW-14 — No Trend
MW-14 pH
,
Figure — U Data Plot of Historical Data at MW-14 — Decreasing Trend
MW-14 U I
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EFR June 25, 2018 MW-14 Source Assessment Report
DWMRC Review Memo
Page 3
Figure — pH Data Plot of Historical Data at MW-14 — No Trend
MW-14 pH
EFR is proposing that the use of a higher GWCL for fluoride be allowed for consideration under the Utah
Administrative Code (UAC) R-317-6. EFR states that the use of a fraction approach is in conformance
with the Director approved statistical flow chart for GWCL's in this case. However, per DWMRC review
of the data, including; 1. Visual examination of data time series plots, 2. Test for normality based on a
DWMRC culled data set, 3. Review of data trends showing all flat or decreasing trends, and, 4.
Recalculation of mean and standard deviation; the use of mean + 2 standard deviations is the appropriate
method to calculate the GWCL and is in conformance with the statistical flow chart. Furthermore, since
the data is showing a decreasing trend for fluoride in MW-14, there is no implicated source for decreasing
concentrations and, since the cause of the consecutive exceedances appears to be due to an outlier in the
data related to laboratory interferences it is not expected that higher concentrations will persist at the well.
Therefore, there is no justification to consider maximum GWCL concentrations potentially allowed by
UAC R317-6.
EFR notes in the SAR that a change in laboratory and analytical method for fluoride occurred in 2012 and
that the new method identified that extreme outliers noted in the data were most likely the result of an
"analytical interference issue" and began diluting fluoride samples to remove matrix interference. The
December 2017 sample for fluoride in MW-14 is likely due to matrix interference during laboratory
analysis.
According to DWMRC visual review of the data it appears that a data point of inflection occurred earlier in
the data than the 2012 change in laboratory and method. An evident point of inflection can be seen starting
with the February 2, 2010 sample. According to the EPA Unified Statistical Guidance it is appropriate to
use the more recent data from this point of inflection and eliminate earlier data from the data set. This
resulted in a DWMRC culled data set or 38 laboratory results of more recent data. Based on the DWMRC
calculations there was one outlier in the culled data set (verified using Rosners Test) which as discussed
above, was the apparent reason that monitoring well MW-14 went into out of compliance status. DWMRC
also removed three non-detected concentrations from the data set. This resulted in a total data set of 34
laboratory results. Elimination of the outlier resulted in a normal distribution of data for the DWMRC
culled data set. Based on evaluation of this data set the mean + 2 standard deviations calculation was 0.21
mg/L.
Conclusions:
Based on DWMRC review of the background statistics, fluoride is showing a decreasing trend. Data is
normally distributed based on the DWMRC post 2/2/2010 data set (point of inflection) and removal of a
verified outlier. Per the currently approved statistical flow chart, the GWCL should be set according to
EFR June 25, 2018 MW-14 Source Assessment Report
DWMRC Review Memo
Page 4
mean + 2 standard deviations. The EFR calculation of mean + 2 standard deviations based on the entire
data set was 0.22 mg/L and is included in Appendix B-1 of the SAR. Although the EFR data set set did not
show normal or lognormal distribution, the EFR result is within the range of DWIVIRC calculations and
therefore, the EFR result appears to be protective and reflective of the fluoride data.
Based on review a letter will be sent to EFR of initial approval of the modified fluoride GWCL (0.22
mg/L) as summarized on the table below. The letter will include notification that the modifications are
subject to public notice and public participation requirements, and that the modifications will not be
effective until formal issuance of a modified Permit.
Well Number Parameter Current GWCL Modified GWCL Method of Analysis
MW-14 Fluoride 0.2 mg/L 0.22 mg/L Mean + 2 Standard
Deviations
References
I Energy Fuels Resources (USA) Inc., June 25, 2018, Transmittal of Source Assessment Report for Fluoride
in MW-14 White Mesa Mill Groundwater Discharge Permit UGW370004
2 Energy Fuels Resources (USA) Inc., August 15, 2017, White Mesa Uranium Mill Ground Water
Monitoring Quality Assurance Plan (QAP), Revision 7.3
3 Intera, 2007, Groundwater Data Preparation and Statistical Process Flow for Calculating Groundwater
Protection Standards, White Mesa Mill Site, San Juan County, Utah
4 Utah Department of Environmental Quality, January 19, 2018, Utah Division of Radiation Control,
Ground Water Discharge Permit, Permit No. UGW370004, Energy Fuels Resources (USA) Inc.
5 U.S. Environmental Protection Agency, March 2009, Statistical Analysis of Groundwater Monitoring
Data at RCRA Facilities Unified Guidance.
DWMRC Statistical Calculations - Fluoride in Monitoring MW-14
Shapiro Wilk (n<50) Method Data Entered 7/9/18 TR
Energy Fuels Monitoring Well MW-14 Fluoride Data Collected Since 2/2/2010
x(n-1+1) x(n-i+1)NO) a(n-i+1) bi
1 0.1 0.22 0.12 0.4127 0.049524
2 0.109 0.217 0.108 0.2854 0.0308232
3 0.109 0.2 0.091 0.2439 0.0221949
4 0.11 0.191 0.081 0.2132 0.0172692
5 0.115 0.188 0.073 0 882 0.0137386
6 0.12 0.172 0.052 0.1667 0.0086684
7 0.121 0.17 0.049 0.1475 0.0072275
8 0.134 0.169 0.035 0.1301 0.0045535
9 0.137 0.166 0.029 0.114 0.003306
10 0.139 0.16 0.021 0.0988 0.0020748
11 0.148 0.16 0.012 0.0844 0.0010128
12 0.149 0.158 0.009 0.0706 0.0006354
13 0.15 0.154 0.004 0.0572 0.0002288
14 0.15 0.153 0.003 0.0441 0.0001323
15 0.15 0.15 0 0.0314 0
16 0.15 0.15 0 0.0187 0
17 0.15 0.15 0 0.0062 0
18 0.15 0.15
19 0.15 0.15
20 0.15 0.15
21 0.153 0.15
22 0.154 0.15
23 0.158 0.149
24 0.16 0.148
25 0.16 0.139
26 0.166 0.137
27 0.169 0.134
28 0.17 0.121
29 0.172 0.12
30 0.188 0.115
31 0.191 0.11
32 0.2 0.109
33 0.217 0.109
34 0.22 0.1
total =
MW-14 Fl Data
X(i)
Rosners Level Critical Points
n(30) .05= 3.05
<0.1
<0.1 Rosners Test
<0.1 r0=1
0.1 1
0.109 2 x0 0.157971429
0.109 3 sO 0.045263598
0.11 4 y0 0.36
0.115 5 x 1 0.152029412
0.12 6 sl 0.028942456
0.121 7 y1 0.22
0.134 8
0.137 9 FIO 4.463378557 RO>3.05
0.139 10 R1 2.348473384
0.148 11
0.149 12
0.15 13
0.15 14
0.15 15
0.15 16
0.15 17
0.15 18
0.15 19
0.15 20
0.153 21
0.154 22
0.158 23
0.16 24
0.16 25
0.166 26
0.169 27
0.17 28
0.172 29
0.188 30
0.191 31
0.2 32
0.217 33
0.22 34
0.36 35

0.1613894 Outliers
Removed non detects Mean = 0.152029412
Standard Deviation = 0.028942456
W Statistic = 0.942248169 normal distribution Shapiro Wilk.01 W Critical n(34) = 0.908
DRC Calculated Limit 0.210 mg/L
Current Limit 0.2 mg/L