DRC-2023-073148 - 0901a0688128898f

September 27, 2023
Div of Waste Management
and Radiation Control
SEP 2 9 2023
Sent VIA E-MAIL ANO OVERNIGHT DELIVERY
Mr. Doug Hansen
Director
Division of Waste Management and Radiation Control
Utah Department of Environmental Quality
l 95 North l 950 West
Salt Lake City, UT 84114-4880
Energy Fuel · Re ources ( SA) Inc,
225 Union Blvd. uite 600
Lal..ewood, CO. ll , 802211
303 9 .t '1-'0
"1 , . nern, Juel. ,om
Re: Transmittal of Source Assessment Report for MW-11 and MW-37 White Mesa Mill
Groundwater Discharge Permit UGW370004
Dear Mr. Hansen:
Enclosed are two copies of Energy Fuels Resource (USA) lnc.'s (''EFRl 's") Source Assessment Report
(' SAR") for MW-11 and MW-37 at the White Mesa Mill. This SAR addresse the constituents that were
identified as exceeding the GWCL in the I st Quarter 2023 as described in the Division of Waste Management
and Radiation Control ("DWMRC")-approved QI 2023 Plan and Time Schedule. EFRl submitted the Plan and
Time Schedule on May 24, 2023. DWMRC approval of the Plan and Time Schedule was received by EFRI on
June 29, 2023. Pursuant to the Plan and Time Schedule EFRl has prepared this SAR.
This transmittal also includes two CDs each containing a word searchable electronic copy of the report.
If you should have any questions regarding this report plea e contact me.
Yours very truly,
i(~Jlr~
E ERGY FUELS RESOURCE (USA) INC.
Kathy Weioel
Director, Regulatory Compliance
CC: Jordan App
David Frydenlund
Garrin Palmer
Logan Shumway
Scott Bakken
Stewart Smith (HGC)
Angie Persico (Intera)
DRC-2023-073148
'?;or.'
'l,.~NERGYFUELS
September 27, 2023
Sent VIA E-MAIL AND OVERNIGHT DELIVERY
Mr. Doug Hansen
Director
Division of Waste Management and Radiation Control
Utah Department of Environmental Quality
195 North 1950 West
Salt Lake City, UT 84114-4880
Energy Fuels Resources (USA) Inc.
225 Union Blvd. Suite 600
Lakewood, CO, US, 80228
303 974 2140
'NWW.energyfuel .com
Re: Transmittal of Source Assessment Report for MW-11 and MW-37 White Mesa Mill
Groundwater Discharge Permit UGW370004
Dear Mr. Hansen:
Enclosed are two copies of Energy Fuels Resource (USA) Inc.'s ("EFRI's") Source Assessment Report
("SAR") for MW-11 and MW-37 at the White Mesa Mill. This SAR addresses the constituents that were
identified as exceeding the GWCL in the 1st Quarter 2023 as described in the Division of Waste Management
and Radiation Control ("DWMRC")-approved QI 2023 Plan and Time Schedule. EFRI submitted the Plan and
Time Schedule on May 24, 2023. DWMRC approval of the Plan and Time Schedule was received by EFRI on
June 29, 2023. Pursuant to the Plan and Time Schedule EFRI has prepared this SAR.
This transmittal also includes two CDs each containing a word searchable electronic copy of the report.
If you should have any questions regarding this report please contact me.
Yours very truly,
-f{~Jv~
ENERGY FUELS RESOURCES (USA) INC.
Kathy W einel
Director, Regulatory Compliance
CC: Jordan App
David Frydenlund
Garrin Palmer
Logan Shumway
Scott Bakken
Stewart Smith (HGC)
Angie Persico (Intera)
White Mesa Uranium Mill
State of Utah Groundwater Discharge Permit No. UGW370004
Source Assessment Report Under Part I.G.4
For Exceedances in MW-11 and MW-37 in the First Quarter of2023
. Prepared by:
?;o~
f.j#;~ERGYFUELS
Energy Fuels Resources (USA) Inc.
225 Union Boulevard, Suite 600
Lakewood, CO 80228
September 27, 2023
EXECUTIVE SUMMARY
This Source Assessment Report ("SAR") is an assessment of the sources, extent, and potential
dispersion of selenium in MW-11 and field pH in MW-3 7 at the White Mesa Mill ("the Mill") as
required under State of Utah Groundwater Discharge Permit UGW370004 (the "GWDP") Part
I.G.4 relating to violations of Part I.G.2 of the GWDP. Selenium in MW-11 and field pH in MW-
37 have exhibited exceedances of the applicable Groundwater Compliance Limits ("GWCLs").
MW-11 has been included in multiple recent investigations and reports, including the Revised
Background Groundwater Quality Report for Existing Wells (INTERA, 2007a), a Regional
Background Report (INTERA, 2007b ), an isotopic investigation (Hurst and Solomon, 2008), a
2012 SAR (INTERA, 2012a), a pH Report (INTERA, 2012b), a 2019 SAR (INTERA, 2019), and
a 2022 SAR (EFRI, 2022). Increasing concentrations of constituents in MW-11 including indicator
parameter sulfate, were present at the time of the isotopic investigation (Hurst and Solomon, 2008)
which demonstrated no groundwater impacts from the tailings management system ("TMS"). The
previous SARs noted that the trends in MW-11 were due to natural influences, consistent with the
conclusions of Hurst and Solomon (2008) which included MW-11 in their analysis.
Subsequent to about 2018, both nitrate and chloride show unambiguously increasing trends at
MW-11. Although MW-11 is not within the nitrate/chloride plume (because nitrate and chloride
concentrations are below 10 milligrams per liter ("mg/L") and 100 mg/L, respectively), these
increasing trends are consistent with ongoing downgradient migration of the plume toward MW-
11. Selenium concentrations in MW-11 have increased since about fourth quarter 2021
subsequent to the increasing nitrate and chloride trends. The selenium increases are attributable
primarily to the oxidation of naturally occurring pyrite that contains selenium as a contaminant
and mobilization of naturally occurring selenium by nitrate (including via oxidation of pyrite by
nitrate) as the nitrate plume migrates towards MW-11. This conclusion is supported by the fact
that indicator parameter fluoride has exhibited a significantly downward trend, indicator
parameter sulfate which has exhibited a significantly increasing trend in the past due to
background influences, has not exhibited an upward trend since July 2019, (the period during
which selenium has exhibited an upward trend) and indicator parameter uranium has exhibited
an upward trend but this trend has been attributed to pyrite oxidation with stable to increasing
pH, as described in detail below.
Additional factors that contributed to changes in groundwater conditions at MW-11 are discussed
in Section 3.0 of this SAR. These factors include the site-wide pH changes, wildlife pond
seepage, and the location of MW-11 immediately downgradient of the nitrate/chloride plume
which extends approximately 1,000 feet upgradient of the TMS.
ES-i
GWCLs for field pH in MW-37 were calculated at the time of the background report in May 2014
using 11 data points. Although a minimum of eight data points are required according to the
DWMRC-approved Flowsheet (from INTERA [2007a], included as Appendix D), this number is
truly a minimum requirement. The strength of the statistical analysis will increase with more data
points, and caution should be used when setting GWCLs for constituents with a limited data set
(fewer than 20 samples, per United States Environmental Protection Agency ["USEP A"] Unified
Guidance [USEPA, 2009]). Evaluation of field pH and indicator parameters in MW-37 indicate
the exceedances of field pH in MW-37 are due to the unrepresentative data set used to calculate the
GWCL at the time of the background report (2014). Significantly more data points are now
available, providing a more robust understanding of the water quality and behavior of groundwater
conditions at MW-37 and allowing for revision of the GWCL using a more representative data set.
As the results of this analysis will demonstrate, trends in MW-11 and MW-37 are the result of
background conditions unrelated to potential seepage from the disposal of materials in the TMS.
In addition, selenium in MW-11 and field pH in MW-37 are within the range of site-wide
conditions.
Revising the GWCLs to reflect the variations in selenium in MW-11 and field pH in MW-37 is
proposed. In accordance with the DWMRC-approved Flowsheet (from INTERA [2007a],
included as Appendix D), increasing trends may necessitate a modified approach, which has
been approved in previous SARs, for calculation of GWCLs. A modified approach for
calculating a revised GWCL for selenium in MW-11 used the greater of (1) mean plus two
standard deviations, (2) highest historical value, or (3) mean x 1.25 to determine representative
and appropriate GWCLs for trending constituents. The GWCL for field pH was calculated using
the lowest historical value, following the DWMRC-approved Flowsheet. Regular revisions to
GWCLs for constituents in wells with significantly increasing trends over time due to
background is consistent with the United States Environmental Protection Agency ("USEP A")
Unified Guidance (USEP A, 2009). Such revisions account for variability in larger datasets and
minimize unwarranted out-of-compliance status.
ES-ii
TABLE OF CONTENTS
1.0 INTRODUCTION ................................................................................................................ 1
1.1 Source Assessment Report Organization .......................................................................... 3
2.0 CATEGORIES AND APPROACHES FOR ANALYSIS ................................................... 4
2.1 Approach for Analysis ...................................................................................................... 5
2 .1.1 MW-11 ............................................................................................................................ 5
2.1.2 MW-37 ............................................................................................................................ 6
2.2 Approach for Setting Revised GWCLs ............................................................................. 6
2.3 University of Utah Study .................................................................................................. 7
3.0 RESULTS OF ANALYSIS .................................................................................................. 8
3.1 Site-Wide pH Changes ...................................................................................................... 8
3.1.1 pH Decrease Prior to 2016 .............................................................................................. 9
3.1.2 pH Increase Post-2016 .................................................................................................. 1 l
3.2 Changes in Groundwater ................................................................................................. 11
3.2.1 MW-ll .......................................................................................................................... 12
3.2.2 MW-37 .......................................................................................................................... 12
3 .3 Indicator Parameter Analysis ........................................................................... _ .............. 13
3.3.1 MW-l l .......................................................................................................................... 13
3.3.2 MW-37 .......................................................................................................................... 15
3 .4 Mass Balance Analyses ................................................................................................... 15
3.4.1 MW-l 1 .......................................................................................................................... 15
3.4.2 MW-37 .......................................................................................................................... 16
3.5 Summary ofResults ........................................................................................................ 16
3.5.1 SeleniumatMW-11 ...................................................................................................... 16
3.5.2 Field pH in MW-37 ...................................................................................................... 18
4.0 CALCULATIONS OF GROUNDWATER COMPLIANCE LIMITS .............................. 19
4.1 Modified Approach to Calculation of GWCLs for Trending Constituents ......................... 19
4.2 Flowsheet Approach to Calculating a Revised GWCL for Field pH in MW-37 ................. 20
4.3 Proposed Revised GWCLs .................................................................................................. 20
5.0 CONCLUSIONS AND RECOMENDATIONS ................................................................ .20
6.0 SIGNATURE AND CERTIFICATION ............................................................................. 22
7.0 REFERENCES ................................................................................................................... 24
1
Table 1
Figure IA
Figure 1B
Figure IC
Figure 1D
Figure 2
Figure 3
Figure 4A
Figure 4B
Figure SA
Figure SB
Figure SC
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
LIST OF TABLES
Proposed Revised GWCLs for MW-11
LIST OF FIGURES
White Mesa Site Plan Showing Locations of Perched Wells and Piezometers
Kriged 2nd Quarter, 2023 Water Levels and Plume Boundaries, White Mesa Site
Kriged 4th Quarter, 2011 Water Levels and Plume Boundaries, White Mesa Site
MW-11 Chloride and Nitrate Over Time
MW-11 and MW-37 Groundwater Elevations
MW-11 Chloride and Fluoride Over Time
MW-11 pH Over Time
MW-37 pH Over Time
MW-37 Chloride and Fluoride Over Time
MW-37 Sulfate Over Time
MW-37 Uranium Over Time
MW-11 Selenium and Nitrate Over Time
MW-11 Ammonia and Nitrate Over Time
MW-11 Uranium and Nitrate Over Time
MW-11 Iron Over Time
MW-11 Sulfate Over Time
11
LIST OF APPENDICES
Appendix A Statistical Analysis for MW-11 and MW-37 SAR Constituents
A-1 Summary of Statistical Analysis for Out of Compliance Constituents in MW-
11 and MW-37
A-2 Comparison of Calculated and Measured TDS in MW-11 and MW-37
A-3 Charge Balance Calculations for Major Cations and Anions in MW-11 and
MW-37
A-4 Descriptive Statistics for Out of Compliance Constituents in MW-11 and
MW-37
A-5 MW-11 and MW-37 Data Used for Statistical Analysis
A-6 Extreme Outliers Removed from Analysis
A-7 Box Plots ofMW-11 and MW-37
A-8 Box Plots for SAR Parameters in Groundwater Monitoring Wells
A-9 Histograms ofMW-11 and MW-37
A-10 Timeseries Plots ofMW-11 and MW-37
Appendix B Statistical Analysis for Indicator Parameters in MW-11 and MW-37
B-1 Summary of Statistical Analysis for Indicator Parameters in MW-11 and
MW-37
B-2 Descriptive Statistics for Indicator Parameters in MW-11 and MW-37
B-3 MW-11 and MW-37 Indicator Parameter Data Used for Analysis
B-4 Indicator Parameter Data Removed from Analysis
B-5 Box Plots for Indicator Parameters in MW-11 and MW-37
B-6 Histograms for Indicator Parameters in MW-11 and MW-37
B-7 Timeseries Plots for Indicator Parameters in M-11 and MW-37
Appendix C Mass Balance Calculations
Appendix D Flowsheet (Groundwater Data Preparation and Statistical Process Flow for
Calculating Groundwater Protection Standards, White Mesa Mill Site
[INTERA, 2007a])
Appendix E Input and Output Files (Electronic Only)
iii
ACRONYM LIST
Background Reports
CAP
CFCs
CIR
DI
Director
DWMRC
EFRI
GWCL
GWDP
GWQS
µg/L
mg/L
Mill
Ql
Q2
Q3
Q4
SAR
TDS
TMS
USEPA
collectively refers to relevant background reports for this well and site:
the Existing Wells Background Report (INTERA, 2007a), the Regional
Background Report (INTERA, 2007b), and the New Wells Background
Report (INTERA, 2008)
Corrective Action Plan
chlorofluorocarbons
Contaminant Investigation Report
Deionized
Director of the Division of Waste Management and Radiation Control
State of Utah Division of Waste Management and Radiation Control
Energy Fuels Resources (USA) Inc.
Groundwater Compliance Limit
State of Utah Ground Water Discharge Permit UGW370004
Groundwater Quality Standard
micrograms per liter
milligrams per liter
White Mesa Uranium Mill
first quarter
second quarter
third quarter
fourth quarter
Source Assessment Report
Total Dissolved Solids
Tailings Management System
United States Environmental Protection Agency
IV
1.0 INTRODUCTION
Energy Fuels Resources (USA) Inc. ("EFRI") operates the White Mesa Uranium Mill
(the "Mill"), located near Blanding, Utah (Figure lA). Groundwater at the Mill is
regulated under the State of Utah Groundwater Discharge Permit UGW370004 (the
"GWDP"). This is the Source Assessment Report ("SAR") required under Part I.G.4 of
the GWDP relating to Part I.G.2 of the GWDP with respect to selenium in MW-11 and
field pH in MW-37.
Part I.G.2 of the GWDP provides that an out-of-compliance status exists when the
concentration of a constituent in two consecutive samples from a compliance monitoring
point exceeds a groundwater compliance limit ("GWCL") in Table 2 of the GWDP. The
GWDP was originally issued in March 2005, at which time GWCLs in MW-11 were set
on an interim basis, based on fractions of State of Utah Ground Water Quality Standards
("GWQSs") or the equivalent, without reference to natural background at the Mill. The
GWDP also required that EFRI prepare a background groundwater quality report to
evaluate all historical data for the purposes of establishing background groundwater
quality at the Mill site and developing GWCLs under the GWDP for MW-11. As
required by then Part I.H.3 of the GWDP, EFRI submitted three "Background
Groundwater Quality Reports" (INTERA 2007a, 2007b, 2008) (collectively, the
"Background Reports") to the Director (the "Director") of the State of Utah Division of
Waste Management and Radiation Control ("DWMRC") (the Director was formerly the
Executive Secretary of the Utah Radiation Control Board and the Co-Executive Secretary
of the Utah Water Quality Board).
Based on a review of the Background Reports and other information and analyses, the
Director re-opened the GWDP and modified the GWCLs to be equal to the mean
concentration plus two standard deviations ("mean + 2o") or the equivalent for each
constituent in each well, based on an "intra-well" approach. That is, the compliance status
for each constituent in a well is determined based on current concentrations of that
constituent in that well compared to the historical concentrations for that constituent in
that well, rather than compared to the concentrations of the same constituent in other
monitoring wells. The modified GWCLs for MW-11 became effective on January 20,
2010. On January 19, 2018, March 19, 2019, and March 8, 2021, revised GWDPs were
issued, which set revised GWCLs for certain constituents in certain monitoring wells as
approved by the Director through previously approved SARs relating to those
constituents in those wells. GWCLs apply to groundwater monitoring wells located in the
perched aquifer at the Mill.
1
MW-37 was installed on the southern edge of Cell 4B, in 2011. A Background Report for
MW-35, MW-36, and MW-37 (INTERA, 2014) was prepared to meet the requirements
stated in then Part I.H.5 of the Mill's GWDP issued by the DWMRC on August 24, 2012.
The GWCLs in MW-37 were calculated in accordance with the DWMRC-approved
Flowsheet (from INTERA [2007a], included as Appendix D) and are equal to mean+ 2o
or the equivalent for each constituent in each well, based on the "intra-well" approach. As
discussed above, the compliance status for each constituent in a well is determined based
on current concentrations of that constituent in that well compared to the historic
concentrations for that constituent in that well, rather than compared to the concentrations
of the same constituent in other monitoring wells. The GWCLs for MW-37 became
effective on January 19, 2018.
Figure 1 B is a site map showing perched well and piezometer locations, second quarter
("Q2") 2023 perched groundwater elevations, and other relevant site features, such as the
locations of formerly used (unlined) wildlife ponds, the historical pond, and the
boundaries of two shallow groundwater plumes (the nitrate/chloride plume and the
chloroform plume) which are under active remediation by pumping. Specifically, Figure
lB shows the commingled nitrate and chloride components of the nitrate/chloride plume.
Figure IC shows the same features as Figure lB, except that water levels and plume
boundaries are as they existed just prior to cessation of water delivery to the wildlife
ponds in the first quarter ("Ql") of 2012. As shown in Figures lB and IC, perched
groundwater flows generally to the southwest across the site, and the nitrate/chloride
plume extends more than 1,000 feet upgradient of the Tailings Management System
("TMS") indicating an upgradient source. As discussed in HGC (2018), the chloroform
plume originated from disposal of laboratory wastes to two former sanitary leach fields
that were used prior to Mill construction and operation. Both Figures lB and 1 C show
that MW-11 is located immediately downgradient of the nitrate/chloride plume. Figure
1D, which shows increasing nitrate and chloride over time at MW-11, indicates that,
while MW-11 is not yet within the nitrate/chloride plume, it is under the influence of the
leading edge of the plume.
Groundwater quality at individual wells is impacted by transient conditions at the site.
Currently the perched groundwater system that is monitored at the site does not approach
steady state over much of the monitored area. A large part of the site perched water
system is in a transient state and affected by long-term changes in water levels due to past
and current activities unrelated to the disposal of materials to the TMS. Changes in water
levels have historically been related to seepage from the unlined wildlife ponds; however
past impacts related to the historical pond, and to a lesser extent formerly used sanitary
leach fields, have also influenced water levels, as discussed in HGC (2018). Water levels
2
have decreased at some locations due to chloroform and nitrate pumping and reduced
recharge from the wildlife ponds.
Figure 2 is a plot of groundwater elevations over time at MW-11 and MW-37.
Groundwater levels have increased by approximately 19 feet at MW-11 since the well
was installed, and by approximately 17 feet since 1990; and groundwater elevations at
MW-3 7 have increased by more than 6 feet since installation. As discussed above, water
level increases are attributable to former wildlife pond recharge.
1.1 Source Assessment Report Organization
Analyses of SAR parameters and indicator parameters in MW-11 and MW-37 were
performed. A description of the approach used for analysis is provided in Section 2.0, and
the results of the analyses are presented in Section 3.0. The calculation of GWCLs is
discussed in Section 4.0, and conclusions and recommendations are reviewed in
Section 5.0. Section 6.0 provides signature and certification of this document, and
Section 7.0 provides a list ofreferences cited in this SAR.
The appendices comprise the analyses performed for this SAR and are organized in the
following manner: Appendix A contains the statistical analysis performed on selenium in
MW-11 and field pH in MW-37. Appendix B contains the indicator parameter analysis
performed on MW-11 and MW-37. Appendix C summarizes the mass balance analysis.
Appendix D contains the Groundwater Data Preparation and Statistical Process Flow for
Calculating Groundwater Protection Standards, White Mesa Mill Site, San Juan County,
Utah ("Flowsheet") that was developed based on the United States Environmental
Protection Agency's ("USEPA") Statistical Analysis of Groundwater Monitoring Data at
RCRA Facilities, Unified Guidance (USEP A, 2009), which was approved by DWMRC
prior to completion of the Background Reports. Appendix E is included on the compact
disc that accompanies this SAR and contains the electronic input and output files used for
statistical analysis.
Statistical analysis was performed using the software package "R." R is a free statistical
package that allows the analyst to perform statistical analysis and format and output
graphs more effectively than the Statistica software package used in the past. Input and
output files included in Appendix E can be imported into either R or Statistica to
replicate the results presented in this SAR.
3
2.0 CATEGORIES AND APPROACHES FOR ANALYSIS
Previously EFRI has categorized wells and constituents in five categories as follows:
1. Constituents Potentially Impacted by Decreasing pH Trends Across the Site
2. Newly Installed Wells with Interim GWCLs
3. Constituents in Wells with Previously Identified Rising Trends
4. Pumping Wells
5. Other Constituents
This SAR addresses selenium in MW-11 and field pH in MW-37, which both fall into
category five; Other Constituents. Given the varied background groundwater quality at
the site, it cannot be assumed that consecutive exceedances of a constituent in a
monitoring well means that contamination has been introduced to groundwater in that
well.
The location of MW-11 is important when determining potential sources of
contamination. MW-11 is directly downgradient of the nitrate/chloride plume. Nitrate
concentrations at MW-5 (adjacent to MW-11) and MW-11 have historically been
relatively low (non-detect to approximately 1 mg/L). Relatively low nitrate
concentrations at MW-11 are consistent with the relative stability of the downgradient
margin of the nitrate plume. However, since mid-2019, low but detectable nitrate at
MW-11 (up to a maximum of approximately 3.5 mg/L), and increases in chloride, have
been observed. Although MW-11 is not within the nitrate/chloride plume (because
nitrate and chloride concentrations are below 10 mg/Land 100 mg/L, respectively), these
increasing trends are consistent with ongoing downgradient migration of the plume
toward MW-11.
The relative stability of the downgradient (southern) margin of the nitrate component of
the nitrate/chloride plume, evidenced by relatively stable nitrate concentrations at MW-
30 and MW-31 (located in the downgradient toe of the plume as shown in Figure 1B),
implies a degradation mechanism that affects nitrate but not chloride (which is increasing
at MW-30 and MW-31). The most likely mechanism is degradation (reduction) of nitrate
by naturally-occurring pyrite in the formations hosting perched groundwater at the site.
The consecutive exceedances of field pH in MW-37 are likely due to background
influences and a small and unrepresentative background data set used to calculate the
GWCLs at the time of the Background Report. Given the recent analyses and
investigations at the site, there is no indication that the exceedances of field pH in MW-
37 are due to Mill-related impacts or to any potential TMS seepage.
4
2.1 Approach for Analysis
The first step in the analysis is to assess the potential sources for the exceedances to
determine whether they are due to background influences or Mill activities. If the
exceedances are determined to be within natural variability or due to site-wide influences,
then it is not necessary to perform further evaluations on the extent and potential
dispersion of the contamination or to perform an evaluation of potential remedial actions.
Monitoring will continue and, where appropriate, revised GWCLs are proposed to reflect
changes in background conditions.
The analysis performed in this SAR considers all available data to date to evaluate the
behavior of the constituents in the wells. Analysis will determine if there have been any
changes in the behavior of potential TMS seepage indicator parameters ( e.g., chloride,
sulfate, fluoride, and uranium) since the date of the Background Reports that may suggest
a change in the behavior of the groundwater in MW-11 and MW-3 7.
2.1.1 MW-11
As discussed in the Background Reports (INTERA, 2007a, 2007b, 2008), indicator
parameters of potential TMS seepage include chloride, sulfate, fluoride, and uranium.
Chloride is typically the best indicator of potential TMS seepage; however, chloride is
problematic as an indicator parameter for groundwater monitoring wells at the Mill
impacted by the nitrate/chloride plume which originates upgradient of the TMS (Figures
lB and IC) (HGC, 2018). Although MW-11 is not within the nitrate/chloride plume, it is
immediately downgradient of the plume and is now affected by elevated concentrations
of chloride and nitrate at the leading edge of the plume.
Sulfate and fluoride are useful indicator parameters when the geochemical conditions
allow these constituents to behave conservatively (i.e., are non-reactive). However,
because sulfate has displayed a long-term increasing trend in MW-11 that was present at
the time that the Hurst and Solomon isotopic investigation (Hurst and Solomon, 2008;
discussed in Section 2.3) concluded there were no impacts to groundwater from the TMS,
it is also not a useful indicator parameter at MW-11. In addition, although uranium may
be the most mobile metal under some conditions, its behavior ranges from conservative to
non-conservative, and is likely to behave relatively non-conservatively due to relatively
strong sorption expected at the near-neutral pH of MW-11 (see Section 3.3 for further
discussion). Therefore, fluoride is the best indicator parameter at MW-11.
Although any potential seepage from the TMS would be expected to cause increasing
concentrations of chloride, sulfate, fluoride, and uranium, as discussed above, sulfate and
chloride are not useful indicators at MW-11, and uranium is expected to be strongly
retarded compared to fluoride at MW-11 due to sorption and precipitation, and would not
5
show increases in groundwater until sometime after fluoride concentrations had begun to
increase. However, as shown in Figure 3, while chloride is increasing due to the influence
of the nitrate/chloride plume, fluoride is decreasing, indicating that there are no impacts
from the TMS. As noted in Section 12.0 of INTERA (2007a), while the absence of a
rising trend in chloride concentration would demonstrate that there has been no impact
from the TMS, a rising trend in chloride concentration as well as in other indicator
parameters can be due to natural influences unrelated to potential seepage from the
disposal of materials in the TMS.
The evaluation of SAR and indicator parameters in MW-11 was supported by a statistical
analysis that followed the process outlined in the Flowsheet (INTERA, 2007a), a copy of
which is attached as Appendix D. The Flowsheet was designed based on USEPA's
Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities, Unified
Guidance (USEP A, 2009), and was approved by DWMRC prior to completion of the
Background Reports.
2.1.2 MW-37
The consecutive exceedances of field pH in MW-37 are likely due to background
influences and a small and unrepresentative background data set used to calculate the
GWCLs at the time of the Background Report. Given the recent analyses and
investigations at the site, there is no indication that the exceedances of field pH in MW-
37 are due to Mill-related impacts or to any potential TMS seepage.
Indicator parameter analysis demonstrates that there are no significant increasing trends
in chloride, fluoride, sulfate or uranium concentrations; rather these parameters are stable
to decreasing as shown in Appendix B-7.
As with MW-11, the evaluation of pH and indicator parameters in MW-37 was supported
by a statistical analysis that followed the process outlined in the Flowsheet (INTERA,
2007a), a copy of which is attached as Appendix D. The Flowsheet was designed based
on USEPA's Statistical Analysis of Groundwater Monitoring Data at RCRA Facilities,
Unified Guidance (USEP A, 2009), and was approved by DWMRC prior to completion of
the Background Reports.
2.2 Approach for Setting Revised GWCLs
If the preceding approach resulted in the conclusion that the analysis in the Background
Reports has not changed, or that the increasing concentrations of selenium in fy1W-11; or
decreasing field pH in MW-37; are due to natural, background variability (or changes) in
groundwater; geochemical changes caused by the downgradient migration of the
6
nitrate/chloride plume; or site-wide influences such as the oxidation of pyrite; then a new
GWCL may be proposed. In proposing revised GWCLs, the DWMRC-approved
Flowsheet approach was adopted, including the last decision of the process that directs
the analyst to consider a modified approach to determining a GWCL if an increasing
trend is present ( or decreasing trend in the case of pH).
Appendix A-1 summarizes the geochemical analysis for selenium in MW-11 and field
pH in MW-37 and presents the revised GWCLs for those constituents, based on the
Flowsheet. A modified approach for selenium is being proposed to address issues with
revising GWCLs in constituents with significantly increasing trends and to minimize
unwarranted out-of-compliance situations.
2.3 University of Utah Study
At the request of the DWMRC, T. Grant Hurst and D. Kip Solomon of the Department of
Geology and Geophysics of the University of Utah performed a groundwater study (the
"University of Utah Study") at the Mill site in July 2007 (Hurst and Solomon, 2008). The
purpose of this study was to characterize groundwater flow, chemical composition, noble
gas composition, and age to evaluate whether the increasing and elevated trace metal
concentrations in monitoring wells at the Mill, all of which were identified in the
Background Reports, may indicate that potential seepage from the TMS is occurring.
To evaluate sources of solute concentrations at the Mill, low-flow groundwater sampling
was used as a method for collecting groundwater quality samples from 15 monitoring
wells, including MW-11. In addition, surface water samples were collected from TMS
cells 1, 3, and 4A, and two wildlife ponds. Passive diffusion samplers were also deployed
and collected to characterize the dissolved gas composition of groundwater at different
depths within the wells. Samples were collected and analyzed for the following
constituents: tritium, nitrate, sulfate, deuterium and oxygen-18 of water, sulfur-34 and
oxygen-18 of sulfate, trace metals (uranium, manganese, and selenium), and
chlorofluorocarbons ("CFCs").
Hurst and Solomon (2008, page iii) concluded generally that,
[t}he data show that groundwater at the Mill is largely older than 50
years, based on apparent recharge dates from chlorofluorocarbons and
tritium concentrations. Wells exhibiting groundwater that has recharged
within the last 50 years appears to be a result of recharge from wildlife
ponds near the site. Stable isotope fingerprints do not suggest
contamination of groundwater by tailings cell leakage, evidence that is
corroborated by trace metal concentrations similar to historically-
observed observations.
7
Hurst and Solomon (2008) conclude that,
[i]n general, the data collected in this study do not provide evidence that
tailings cell leakage is leading to contamination of groundwater in the
area around the White Mesa Mill. Evidence of old water in the majority of
wells, and significantly different isotopic fingerprints between wells with
the highest concentrations of trace metals and surface water sites,
supports this conclusion. The only evidence linking surface waters to
recharging groundwater is seen in MW-27 and MW-19. Measurable
tritium and CFC concentrations indicate relatively young water, with low
concentrations of selenium, manganese, and uranium. Furthermore, stable
isotope fingerprints of oD and 0180 suggest mixing between wildlife pond
recharge and older groundwater in MW-19 and MW-27. D34S-SO4 and
o18O-SO4fingerprints closely relate MW-2 7 to wildlife pond water, while
the exceptionally low concentration of sulfate in MW-27, the only
groundwater site to exhibit sulfate levels below 100 mg/L, suggest no
leachate from the tailings cells has reached the well.
It should be further noted that, subsequent to the University of Utah Study, EFRJ
submitted a Contaminant Investigation Report, White Mesa Uranium Mill Site, Blanding
Utah, dated December 30, 2009 (INTERA, 2009) ("CIR"), in connection with the
nitrate/chloride plume at the Mill site. The CIR discusses the presence of a historical
pond that existed for many years at a location upgradient from MW-27 (Figures lB and
1 C), which was much closer to MW-27 than the wildlife ponds. This historical pond was
a contributor of surface water to MW-27.
MW-37 was not in existence at the time of the University of Utah study and therefore no
assessment was completed for that well.
3.0 RESULTS OF ANALYSIS
This section describes the geochemical influences on groundwater in MW-11 and MW-
37 and results of the analyses, summaries of which are provided in Appendix A-1, and
Appendix B-1 and discussed further below.
3.1 Site-Wide pH Changes
As discussed below, pH in nearly all MW-series monitoring wells, including MW-11 and
MW-37, was decreasing prior to about 2016. This has resulted in mobilization of pH-
sensitive metals and increases in concentrations of these metals in groundwater.
However, since about 2016, the site-wide decreasing pH trend has reversed in nearly all
MW-series monitoring wells (including MW-11 and MW-37), and pH is now generally
stable to increasing.
8
3.1.1 pH Decrease Prior to 2016
As has been documented in INTERA (2012), a decreasing trend in pH was observed in
almost every groundwater monitoring well across the site, including upgradient and far
cross-and downgradient monitoring wells; and decreasing pH is one of the most
important contributors to increasing concentrations of many naturally-occurring
parameters.
Hydro Geo Chem, Inc. (["HGC"], 2012a) ("The Pyrite Report") attributed the decline in
pH across the Mill site to the site-wide existence and oxidation of pyrite in the perched
groundwater monitored at the site. Based on HGC (2012a) pyrite has been noted in
approximately 2h of the lithologic logs for wells installed at the site since 1999, and
verified by laboratory analysis in core and cuttings from at least 25 monitoring wells.
Whereas the lithologic log for MW-3 7 notes the existence of visible pyrite near the base
of the Burro Canyon Formation, the presence or absence of pyrite at MW-11 is unknown
as detailed lithologic logs are not available. However, as discussed in HGC (2012), pyrite
is essentially ubiquitous at the site and is therefore likely present in the Burro Canyon
Formation in the vicinity of MW-11.
Pyrite will oxidize according to the following reaction (Williamson and Rimstidt, 1994):
Reaction 1 will increase hydrogen ion ( acid) concentrations, which results in decreasing
pH. Oxidation of pyrite and the resulting decrease in pH enables subsequent pH-
dependent reactions to occur, including the mobilization of naturally-occurring metals
and metalloids (such as uranium) in the formation (McClean and Bledsoe, 1992). In
addition, pyrite typically contains many contaminants including selenium (Curti, 2013;
Deditius et al, 2011; Diener et al 2012; Grant et al, 2021; Keith, 2018) that are released
upon pyrite oxidation. Furthermore, naturally occurring uranium reduced by and sorbed
onto pyrite (Descotes et al 201 O; Glizaud, 2006) makes it available for release upon
oxidation. As discussed in EFRI (2021), bottle-roll tests using 'generic' pyrite resulted in
bottle-roll solutions initially consisting of laboratory-grade deionized ("DI") water
generating between 25 micrograms per liter ("µg/L") and 3,420 µg/L uranium. Bottle-roll
tests using pyrite-bearing core from the formation hosting perched groundwater at the site
yielded bottle-roll solutions having as much as 6,700 µg/L uranium. In addition, bottle-
roll test solutions generated as much as 64.9 µg/L selenium from the 'generic' pyrite
sample; and as much as 303 µg/L selenium from a pyritic core sample.
The causes for site-wide oxidation of pyrite include processes that mcrease oxygen
transport to groundwater. Monitoring well casings themselves provide direct conduits for
9
oxygen to impact groundwater in the immediate vicinities of the wells. Additional factors
that increase oxygen transport to groundwater include: (1) infiltration of oxidized water
from the wildlife ponds upgradient of the Mill site; (2) changing water levels and
incorporation of oxygen in air-filled pore spaces into groundwater; (3) the introduction of
oxygen during pumping related treatment of the nitrate/chloride plume; and (4) the
introduction of oxygen during increased sampling of monitoring wells (INTERA, 2012).
Many of these mechanisms, in particular changing water levels, are impacting MW-11.
Water levels at many site wells increased due to former seepage from the northern
wildlife ponds located upgradient of the TMS. As shown in Figure 2, as a result of former
wildlife pond seepage and expansion of the resulting perched groundwater mound, water
levels at MW-11 increased by approximately 19 feet since installation; and by
approximately 17 feet since 1990; and water levels at MW-37 have increased by more
than 6 feet since installation.
Although MW-11 is influenced by the downgradient migration of the nitrate/chloride
plume, MW-11 is not within the nitrate plume because the plume is defined in the
Corrective Action Plan ("CAP") as nitrate concentrations greater than 10 mg/L. As
discussed above, the nitrate/chloride plume originates more than 1,000 feet upgradient of
the TMS.
Pyrite is oxidized by nitrate by the following mechanisms as discussed in HGC (2018)
The pathway most commonly applied in geochemical studies (Kolle et al., 1983, 1985;
Postma et al., 1991; Korom, 1992; Robertson et al., 1996; Pauwels et al., 1998; Hartog et
al., 2001, 2004; Spiteri et al., 2008) is a bacteria-mediated reaction that yields ferrous
iron, sulfate, water, and nitrogen gas as follows:
By Reaction 2, five moles of pyrite reduce 14 moles of nitrate, consuming four moles of
acid. Reaction 2 is considered applicable when pyrite concentrations exceed nitrate
concentrations (van Beek, 1999). Where nitrate concentrations exceed pyrite
concentrations, Reaction 3 is a more likely mechanism (Kolle et al., 1987; van Beek,
1999; Schlippers and Jorgensen, 2002):
By Reaction 3, two moles of pyrite reduce six moles of nitrate, yielding iron hydroxide,
sulfate, acid, and nitrogen gas. Therefore, when nitrate concentrations exceed pyrite
concentrations (Reaction 3), denitrification by pyrite is more efficient than when pyrite is
in excess (Reaction 2). Additionally, Reaction 3 produces acid, while Reaction 2
10
consumes acid, indicating that the impact of denitrification by pyrite on aquifer
geochemistry is controlled by the relative abundance of pyrite and nitrate.
Reaction 3 is an overall reaction that combines Reaction 2 and a second step whereby
ferrous iron is oxidized by nitrate. This second step is more likely to occur when excess
nitrate is present and available to oxidize ferrous iron (Kolle et al., 1987; Rivett et al.,
2008; Zhang, 2012).
3.1.2 pH Increase Post-2016
As shown in Figures 4A and 4B, pH at MW-11 and MW-37 generally decreased until
about 2016, then became stable to increasing. The post-2016 increase in pH is
inconsistent with a TMS source as TMS solutions have a low pH, and mixing of potential
seepage of TMS solution with groundwater would cause a decrease (rather than increase)
in pH. The increasing pH shows that MW-11 and MW-37 are unimpacted by the TMS,
consistent with the decreasing fluoride shown in Figure 3 and stable indicator parameters
in MW-37 (Figures SA through SC and Appendix B). Recently increasing chloride in
MW-11, which correlates with increasing nitrate (Figure ID), is the result of
downgradient migration of the nitrate/chloride plume toward MW-11, as will be
discussed in Section 3.3.
3.2 Changes in Groundwater
As discussed in Section 1, Figure lB shows water levels and chloroform, nitrate and
chloride plume boundaries for the second quarter of 2023. Figure IC shows the same
features as Figure lB, except that water levels and plume boundaries are as they existed
just prior to cessation of water delivery to the wildlife ponds. A comparison between
Figure IB and Figure IC shows the substantial changes in water levels that have occurred
in about 11 years due cessation of water delivery to the wildlife ponds. Currently,
although water levels have declined substantially in the center of the perched
groundwater mound associated with the northern wildlife ponds, water levels have not
returned to pre-pond seepage conditions, and consequently the groundwater mound is still
expanding.
The transient status of a large portion of the perched water system, manifested in long-
term changes in saturated thicknesses and rates of groundwater flow, results in trends in
pH and in the concentrations of many dissolved constituents that are unrelated to site
operations. Changes in saturated thicknesses and rates of groundwater flow can result in
changes in concentrations of dissolved constituents (or pH) for many reasons. For
example, as discussed in HGC (2012), groundwater rising into a vadose zone having a
different chemistry than the saturated zone will result in changes in pH and groundwater
11
constituent concentrations. If the rise in groundwater represents a long-term trend, long-
term changes in groundwater constituent concentrations ( or pH) result.
3.2.1 MW-11
Statistical analysis of selenium in MW-11 was performed for the complete historical data
set and for a more recent post-inflection data set containing data from July 2019 -
present. Data used in the analysis are presented in Appendix B-5. Both data sets exhibit
non-parametric distribution with statistically significant increasing concentrations
(Appendix A-1). The trend of increasing selenium concentrations in MW-11 correlates
with increasing nitrate concentrations (Figure 6) and is likely to result from mobilization
from natural sources within the Burro Canyon Formation hosting perched groundwater at
the site. Sources include naturally-occurring pyrite in the formation.
Selenium mobilization by nitrate is discussed in Mills et al (2016); Bailey et al (2012);
Mast (2014); Potoroff et al (2005); and Wright (1999). In addition, selenium is a common
contaminant in pyrite as discussed in Curti (2013); Deditius et al (2011); Diener et al
(2012); Grant et al (2021 ); and Keith (2018). Selenium mobilization by nitrate may
result in whole or in part by oxidation of naturally-occurring pyrite by nitrate.
Prior to about 2016, pH at MW-11 was decreasing significantly (Figure 4A); however,
chloride was stable and nitrate was generally not detected as shown in Figure ID,
indicating that the nitrate/chloride plume had not yet impacted MW-11. The previous
lack of impact by the nitrate/chloride plume is also consistent with stable to slightly
increasing ammonia prior to 2016 as shown in Figure 7. Beginning in 2017 ammonia
stabilized; and then began to decrease at about the same time that nitrate began to
increase (Figure 7), consistent with the influence of the nitrate/chloride plume. The post-
2018 decrease in ammonia and increase in nitrate not only indicate the increasing
influence of the nitrate/chloride plume but are also consistent with increasingly oxidizing
conditions which are favorable for mobilization of selenium.
3.2.2 MW-37
An examination of pH at MW-37 shows that a decreasing trend was present prior to
about 2016; however, post-2016, pH began to rise, as shown in Figure 4B. The pre-2016
decreasing trend may have resulted from pyrite oxidation, as visible pyrite was noted in
the drilling log; however, the post-2016 stable to increasing trend, which is reflected in
most of the MW-series wells at the site, cannot result from TMS seepage mixing into
groundwater as the TMS solutions have a very low pH.
Statistical evaluation of field pH in MW-37 was performed for the complete data set
(N=42) and is presented in Appendix B. Field pH exhibits a non-parametric distribution
12
and does not exhibit a statistically significant increasing trend. Data used in the analysis
are presented in Appendix A-5.
3.3 Indicator Parameter Analysis
A summary of statistical analysis of indicator parameters for MW-11 and MW-37 is
included in Appendix B. The complete data set, indicated as "All 2023 SAR Data," and
the post-inflection data sets for MW-11 were evaluated for each indicator parameter and
are summarized in Appendix B-1. Appendix B-2 presents a descriptive statistics
comparison for MW-11 indicator parameters from the Existing Wells Background Report
(INTERA, 2007a), the 2012 SAR (INTERA, 2012a), the 2019 SAR (INTERA, 2019), the
2022 SAR (EFRI, 2022) and this SAR. Similarly, Appendix B-2 presents a descriptive
statistics comparison for MW-37 indicator parameters from the 2014 MW-35, MW-36,
and MW-37 Background Report (EFRI, 2014) and this SAR. Data used in the indicator
parameter analysis are presented in Appendix B-3. The distribution and identification of
outliers and extreme outliers in indicator parameter concentration datasets are
demonstrated in the box plots included in Appendix B-5. Histograms and time series
plots are included in Appendix B-6 and B-7, respectively.
3.3.1 MW-11
Complete data sets for MW-11 indicator parameters chloride, sulfate and uranium exhibit
significantly increasing trends; whereas fluoride exhibits a significantly decreasing trend
(Appendix B-1). Post-July 2019 inflection data sets for MW-11 indicator parameters
exhibit significant trends for chloride and uranium, while sulfate concentrations exhibit
no trend. The decreasing trend in fluoride concentrations indicates that MW-11 is not
impacted by potential seepage from the TMS. The increase in chloride correlates to an
increase in nitrate and is due to the migration of the nitrate/chloride plume towards MW-
11.
The mcrease m sulfate concentrations in the complete data set is more gradual
(Appendix B-7) than the increase in chloride and uranium concentrations (Appendix B-
7). Sulfate has been increasing since the time of the Existing Wells Background Report
(INTERA, 2007a); and was increasing at the time of the Hurst and Solomon isotopic
investigation report (Hurst and Solomon, 2008). Because the isotopic analysis concluded
that there were no impacts to groundwater from the TMS, the trend in sulfate is indicative
of background conditions unrelated to the disposal of materials to the TMS. Furthermore,
isotopic measurements indicated that MW-11 contained the largest component of water
that predated the TMS (Hurst and Solomon, 2008), additional demonstration of the lack
of a TMS impact. Although sulfate concentrations in MW-11 have been increasing since
13
the time of the Background Report, post-July 2019 data are not increasing significantly
and concentrations remain within the sitewide range of sulfate concentrations at the Mill
as summarized in EFRI (2022). As described in Section 3 .2, sulfate is naturally occurring
in groundwater and is released into solution as a result of pyrite oxidation.
The recent increase in uranium corresponds to nearly simultaneous increases in chloride
and nitrate (Figures ID and 8). However, chloride and nitrate are anions that do not sorb
onto aquifer materials and are not retarded with respect to groundwater flow. In contrast,
uranium is expected to have a mobility that is orders of magnitude lower than chloride or
nitrate at the near-neutral pH conditions at MW-11.
USEPA (2007) provides soil-water equilibrium distribution coefficients (Kd) for
uranium. The higher the Kd, the less mobile uranium is expected to be; and the lower the
Kd, the more mobile uranium is expected to be. As indicated in USEP A (2007), Kd
values for uranium are pH-dependent, with the highest Kd associated with near-neutral to
slightly acidic pH). The minimum Kd values reported for uranium increase from 0.4 mL/g
at pH 4 to 100 mL/g at pH 6; drop to 63 mL/g at pH 7; then drop to 0.4 mL/g at pH 8.
The actual Kd values for uranium at the site are expected to be higher than these
minimum values due to the fine-grained nature of the formations hosting perched
groundwater at the site (USEP A, 1999). USEP A (2007) provides maximum Kd for
uranium that increase from 5,000 mL/g at pH 4; to 1,000,000 mL/g at pH 6; drop to
630,000 mL/g at pH 7; then drop to 250,000 mg/L at pH 8. The actual uranium Kd values
for the Mill are expected to lie within the ranges of minimum and maximum Kd specified
in USEPA (2007). Conversely, Kd for anions such as chloride and nitrate are expected to
be negligible.
In order to impact groundwater at MW-11, any solution seeping from the TMS would
have to penetrate more than 60 feet of vadose materials, then migrate within perched
groundwater toward MW-11. Because, as discussed above, the expected Kd for uranium
is at least one or more orders of magnitude higher than the expected (negligible) Kd for
chloride and nitrate, the substantial retardation of uranium with respect to chloride and
nitrate that would occur would prevent the nearly simultaneous increases in all three
constituents that have been measured. The only condition that would allow simultaneous
increases in constituents with substantially different Kd would be a 'fast pathway' that
could conduct TMS solution directly to the immediate vicinity of MW-11 without
sorption or any other significant attenuation process. However, if such a 'fast pathway'
existed, then nearly simultaneous increases in all TMS constituents would occur, rather
than just a few. In particular, iron, which typically has the highest measured
concentrations in the TMS, would be expected to increase substantially; yet, as shown in
14
Figure 9, iron at MW-11 has decreased in concentration since the first quarter of 2012
and has not been detected since the third quarter of 2018.
Recent increases in uranium are attributable to mobilization of naturally-occurring
uranium by nitrate (Asta et al, 2020; Senko et al, 2002; and Senko et al, 2005) and to
oxidation of pyrite by nitrate (Section 3 .1.1 ). Similar to selenium, and as discussed above,
uranium can exist as a contaminant in pyrite (Descotes et al 2010; Glizaud, 2006). As
discussed above and in EFRl (2021 ), bottle-roll test solutions initially consisting of
laboratory-grade DI water generated between 25 µg/L and 3,420 µg/L uranium from
'generic' pyrite samples. Bottle-roll tests using pyrite-bearing core from the formation
hosting perched groundwater at the site yielded bottle-roll solutions having as much as
6,700 µg/L uranium. Because nitrate oxidation of pyrite can proceed by a pathway that
consumes rather than produces acid, and there is sufficient nitrate to produce the
measured uranium, recently increasing uranium at MW-11 can result from pyrite
oxidation with stable to increasing pH. In addition, as discussed in Section 3 .1.1, bottle-
roll test solutions generated as much as 64.9 µg/L selenium from the 'generic' pyrite
sample; and as much as 303 µg/L selenium from a pyritic core sample.
3.3.2 MW-37
Mann-Kendall test results show that no significant trends exist for MW-37 indicator
parameters (Figures SA through 5C) (Appendix B-1). Linear regression test results for
normally distributed constituents, chloride and uranium show a decreasing trend in
chloride and a significantly decreasing trend in uranium, indicating that there has been no
impact to MW-37 from potential TMS seepage (Appendix B-1; Appendix B-7).
3.4 Mass Balance Analyses
3.4.1 MW-11
Since 1990, water levels at MW-11 have risen by more than 1 7 feet, and the saturated
thickness has increased from approximately 29.8 to 47.1 feet. TMS solutions contain
chloride, a conservative solute, at an average concentration exceeding 28,000 mg/L. If the
water level changes at MW-11 were due to potential TMS seepage, and resulted in a
mixture containing approximately 3 7% TMS solution, chloride concentrations at MW-11
would exceed 10,000 mg/L, rather than the second quarter, 2023 value of approximately
69 mg/L. Similarly, based on the average concentrations (since 2003) in TMS solutions,
the fluoride concentration would exceed 1,200 mg/L (rather than the second quarter, 2023
value of approximately 0.28 mg/L); the sulfate concentration would exceed 67,000 mg/L
(rather than the second quarter, 2023 value of approximately 1,340 mg/L); the uranium
concentration would exceed 143,000 µg/L (rather than the second quarter, 2023 value of
15
approximately 2.6 µg/L); and the selenium concentration would exceed 3,400 µg/L rather
than the second quarter, 2023 value of 15.3 µg/L). These calculations (summarized in
Table C. l of Appendix C) demonstrate that the observed increases in water levels at
MW-11 do not result from potential TMS seepage.
In addition, as discussed above, fluoride concentrations at MW-11 are decreasing (Figure
3 and Appendix C). Because fluoride is a relatively mobile anion, and, after chloride, is
the next most useful indicator parameter, the decreasing trend demonstrates that MW-11
cannot be impacted by potential TMS seepage. Overall, the mass balance analyses and
geochemical considerations demonstrate that potential TMS seepage is not a contributor
to the groundwater chemistry at MW-11.
3.4.2 MW-37
Based on the average water level over the first four quarters after installation
(approximately 5486.6 ft amsl) and the average water level over the last four quarters
(approximately 5493 ft amsl), the water level at MW-37 has increased by more than six
feet and the saturated thickness has approximately doubled. If the water level increase
were the result of TMS seepage, the chloride concentration (currently 45 mg/L) would
exceed 14,000 mg/L; the fluoride concentration (currently about 0.2 mg/L) would exceed
1,700 mg/L; the sulfate concentration (currently 2,580 mg/L) would exceed 91,000 mg/L;
and the uranium concentration (currently 11.7 µg/L) would exceed 194,000 µg/L. These
calculations are summarized in Table C.2 of Appendix C. As the actual concentrations
are orders of magnitude smaller than the concentrations expected if the water level
increase resulted from TMS seepage, the water level increase cannot be the result of
potential TMS seepage.
In addition, as shown in Figures 5A through SC and Appendix B, indicator parameters
chloride, fluoride, sulfate and uranium at MW-37 are stable to decreasing, indicating no
impact from TMS solutions.
3.5 Summary of Results
As will be discussed below, increases in selenium at MW-11; and changes in pH at MW-
37; are the result of background conditions unrelated to disposal of materials to the TMS.
3.5.1 Selenium at MW-11
As discussed above, analysis of indicator parameters shows that MW-11 is un-impacted
by TMS solutions and that increases in selenium result from factors unrelated to disposal
of materials in the TMS. Increases in indicator parameter chloride are attributable to
migration of the nitrate/chloride plume, which originates approximately 1,000 feet
16
upgradient of the TMS. Likewise increases in indicator parameter uramum are
attributable to mobilization by nitrate supplied by migration of the nitrate/chloride plume.
In addition, indicator parameter sulfate (Figure 10) was increasing in MW-11 at the time
of the Hurst and Solomon (2008) isotopic investigation which included MW-11 in its
analysis and concluded that there were no impacts to groundwater from the TMS;
therefore, increases in sulfate are the result of background conditions unrelated to
disposal of materials to the TMS. Decreasing fluoride (Figure 3) and stable to increasing
pH since 2016 (Figure 4A) also indicate that MW-11 groundwater is unimpacted by the
TMS.
As with uranium, increasing selenium is attributable to mobilization of naturally-
occurring selenium in the Burro Canyon formation by nitrate, including release of
selenium present as a contaminant in naturally-occurring pyrite. In addition, as discussed
in Section 3.1 .2, oxidation of pyrite by nitrate can occur via a mechanism that consumes
rather than produces acid, thus releasing selenium without a corresponding pH decrease.
3.5.1.1 Summary of Factors Demonstrating no Impact to MW-11 From the TMS
The following factors indicate that changes in constituent concentrations at MW-11 do
not result from potential TMS seepage:
1. Key indicator parameter fluoride is decreasing.
2. pH has been stable to increasing since 2016.
3. Iron (which is the constituent having the highest concentration in the TMS) has
been decreasing since the first quarter of 2012.
4. A statistically significant increasing trend in indicator parameter sulfate was
present in MW-11 at the time of the Hurst and Solomon (2008) isotopic
investigation report which included MW-11 in its analysis and that concluded
there were no impacts to groundwater from the TMS, indicating that this trend is
not the result of potential TMS seepage. In addition, while the complete data set
for MW-11 sulfate exhibits a significantly increasing trend, the post-inflection
(post-July 2019) data set for MW-11 sulfate exhibits no significant trend.
5. Although not within the plume, concurrently increasing chloride and nitrate at
MW-11 since 2018 result from the increasing influence of the nitrate/chloride
plume. The increasing influence of the nitrate/chloride plume, which originates
approximately 1,000 feet upgradient of the TMS, results from continued
downgradient migration of the plume towards MW-11. One consequence of the
17
increasing nitrate is mobilization of naturally-occurring uranium (and selenium) at
MW-11.
6. Because uranium is substantially less mobile than nitrate or chloride at the near-
neutral pH conditions at MW-11, concurrently increasing uranium, nitrate,
chloride (and selenium) indicate geochemical changes in the immediate vicinity
of MW-11 (caused in part by the increasing influence of the nitrate/chloride
plume) rather than transport from a remote source such as the TMS.
7. Increasing water levels are expected to impact the MW-11 groundwater chemistry
and contribute to trends in dissolved constituents.
8. Mass balance analysis indicates that water level increases at MW-11 do not result
from potential TMS seepage.
Because increasing concentrations of selenium in MW-11 are not the result of potential
TMS seepage, a revised GWCL for selenium is proposed. Section 4 presents the methods
used to calculate a GWCL using a modified approach for trending constituents, in
accordance with the Flowsheet.
3.5.2 Field pH in MW-37
As discussed above, evaluation of field pH and indicator parameters demonstrate that the
behavior of MW-37 has not varied significantly since the time of the background report.
Data that have been collected and appended to the dataset result in a more representative
dataset that accounts for natural variability of concentrations.
3.5.2.1 Summary of Factors Demonstrating no Impact to MW-37 From the TMS
The following factors indicate that changes in pH at MW-37 do not result from potential
TMS seepage:
1. Key indicator parameters chloride, fluoride, sulfate and uranium are stable to
decreasing.
2. pH has been stable to increasing since 2016.
3. Increasing water levels are expected to impact the MW-3 7 groundwater chemistry
and contribute to trends in dissolved constituents.
4. Mass balance analysis indicates that water level increases at MW-37 do not result
from potential TMS seepage.
Because changes in field pH in MW-37 are not the result of potential TMS seepage, a
revised GWCL for pH is proposed. Section 4.0 presents the methods used to calculate a
GWCL in accordance with the Flowsheet.
18
4.0 CALCULATIONS OF GROUNDWATER COMPLIANCE LIMITS
Because selenium in MW-11 is increasing significantly (Appendix A-1, and A-10), the
Flowsheet (Appendix D) dictates that a modified approach should be used to calculate a
GWCL. Section 4.1 describes the rationale used to select a modified approach for
calculating a GWCL for selenium in MW-11. Since pH in MW-37 does not exhibit a
significantly decreasing trend, the revised GWCL was calculated in accordance with the
Flowsheet as described in Section 4.2.
4.1 Modified Approach to Calculation of GWCLs for Trending Constituents
According to the DWMRC-approved Flowsheet, if an increasing trend is present, a
modified approach should be considered for determining GWCLs. The modified
approach used for selenium in MW-11 includes calculating a revised GWCL by selecting
the greater of (1) mean + 2cr, (2) highest historical value, or (3) mean x 1.25 using a
complete dataset or subset of the data defined by a point of inflection to determine
representative and appropriate GWCLs for trending constituents.
As discussed in Section 3.2, selenium in MW-11 exhibits a significantly increasing trend
that can be attributed to sitewide conditions that are mobilizing naturally occurring
selenium. The mobility of selenium in groundwater is sensitive to increases in nitrate
concentrations as discussed in Section 3 .2.1. Nitrate concentrations were typically below
the laboratory reporting limit of 0.1 mg/L until the July 2019 sampling event where a
steady increase in nitrate concentrations thereafter is observed. July 1, 2019, serves as the
point of inflection used to define a recent subset of representative data that can be used to
calculate a revised GWCL for selenium. Although the complete data set and the post-
July 2019 data set were evaluated, the modified approach for the proposed GWCL for
selenium is based on the mean + 2cr of the post-July 2019 data set.
Concentrations of selenium and other parameters associated with nitrate oxidation of
naturally occurring pyrite (i.e. sulfate and uranium) are likely to continue to increase and
regular evaluation and revision of GWCLs will be necessary to minimize unwarranted
out-of-compliance status.
Calculation of GWCLs using a modified approach decreases the likelihood of false
positives ( exceedances) associated with increasing trends related to natural background
conditions including site-wide oxidation of pyrite. The proposed GWCL maintains the
intra-well approach that has been established for compliance at the Mill, combining
elements from the Flowsheet and from previously approved GWCLs calculated using a
modified approach. The flowsheet calculations and the proposed GWCLs using the
modified approach, are presented in Appendix A-1 and Table 1, respectively.
19
4.2 Flowsheet Approach to Calculating a Revised GWCL for Field pH in MW-37
Field pH in MW-37 does not exhibit a significant decreasing trend and is not normally
distributed. The flowsheet (Appendix D) dictates that the greater (lower in the case of
pH) of the fraction approach or the highest historic value (lowest historical value in the
case of pH) is selected for the proposed GWCL in these circumstances. Because field pH
is measured on a logarithmic scale, the fractional approach results in a value that is
unnecessarily low (Appendix B-1). Therefore, the proposed GWCL for field pH in MW-
37 is based on the lowest historical value.
4.3 Proposed Revised GWCLs
GWCLs determined according to the Flowsheet are presented in Table 1.
Table 1
Proposed Revised GWCLs for MW-11 and MW-37
Well Parameter Current Proposed Rationale (units) GWCL GWCL
MW-11 Selenium 12.5 20.49 Modified Approach mean + 2a
(µg/L) using post July 1, 2019 data set
MW-37 pH (s.u.) 6.61-8.5 6.05 Lowest Historical Value
5.0 CONCLUSIONS AND RECOMENDATIONS
The Mill site was thoroughly studied in the Background Reports (INTERA, 2007a,
2007b, 2008, 2014), in various SARs, and in the University of Utah Study (Hurst and
Solomon, 2008). The Background Reports and the University of Utah Study concluded
that groundwater at the Mill site, including in MW-11, has not been impacted by Mill
operations. Both of those studies also acknowledged that there are natural influences at
play at the Mill site that have given rise to increasing trends and general variability of
background groundwater quality at the Mill site.
The focus of this SAR was, therefore, to identify any changes in the circumstances
identified in those studies. Evaluation of SAR parameters and indicator parameters in
MW-11 were performed in accordance with the DWMRC-approved Flowsheet
(Appendix D).
With regard to MW-11, although indicator parameters chloride, sulfate and uranium
exhibit significantly increasing trends, fluoride is significantly decreasing. Nearly
simultaneous increases in chloride and nitrate are caused by migration of the
nitrate/chloride plume (which extends approximately 1,000 feet upgradient of the TMS)
20
toward MW-11. Stable to increasing pH (since 2016) and decreasing fluoride indicate
that MW-11 is unimpacted by the TMS.
In addition, indicator parameter sulfate (which has not been significantly increasing since
July 2019) was already increasing in MW-11 at the time that the University of Utah study
which included MW-11 in its analysis, concluded that there were no impacts to
groundwater from the TMS; and iron, the metal that exists at the highest concentrations
in the TMS solutions, has been decreasing since the first quarter of 2012. Both factors
indicate there are no impacts from the TMS. Furthermore, mass balance analysis
indicates that increases in water levels at MW-11 do not result from potential seepage
from the TMS and analysis demonstrates that the currently increasing trend in uranium in
MW-11 is due to pyrite oxidation with stable to increasing pH, and not to potential TMS
seepage.
With regard to MW-37, indicator parameters chloride, fluoride, sulfate and uranium are
stable to decreasing; and pH has been stable to increasing since 2016, indicating no
impacts from the TMS. In addition, mass balance analysis indicates that water level
increases at MW-37 do not result from potential TMS seepage.
EFRI recommends adopting the revised GWCLs for MW-11 and MW-37 in accordance
with the Flowsheet. Regular revisions to GWCLs are consistent with the USEP A Unified
Guidance (USEP A, 2009). Such revisions account for variability in larger datasets and
minimize unwarranted out-of-compliance status.
21
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147.
Kolle, W., 0. Strebel, and J. Bottcher. 1985. Formation of sulphate by microbial
denitrification in a reducing aquifer. Water Supply 1985, 3, 35-40
Kolle, W., 0. Strebel, and J. Bottcher. 1987. Reduced sulphur compounds in sandy
aquifers and their interactions with groundwater. Proceedings of the Dresden
Symposium of Groundwater Monitoring and Management, March 1987.
Korom, S.F. 1992. Natural denitrification in the saturated zone: A review. Water
Resources Research, 1992, 28, 1657-1668
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Selenium From the Mancos Shale and Associated Soils in the Lower
Uncompahgre River Basin, Colorado. Applied Geochemistry, Vol 48, pp 16-27.
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York. 480p.
Pauwels, H., W. Kloppmann, J.C. Foucher, A. Martelat, and V. Fritsche. 1998. Field
tracer test for denitrification in a pyrite-bearing schist aquifer. Applied
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unconfined sandy aquifer -water chemistry, reduction processes, and
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attenuation in groundwater: A review of biogeochemical controlling processes.
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28
FIGURES
APPENDICES
APPENDIX A
Appendix A-2: Comparison of Calculated and Measured TDS in MW-11 and MW-37
I
Alkalinity
Well Date Sampled (mg/Las Calcium Chloride
(mg/L) (mg/L) HCO,)
-_ , ---------------
MW-11 12/16/1982 399 36 24.4
MW-11 5/24/1983 363 31 26.8
MW-11 10/26/1983 402 28 26
MW-11 6/12/1984 330 29 32
MW-11 11/27/2000 382 94 37.3
MW-11 11/6/2001 375 82.9 42.4
MW-11 9/10/2002 372 90.8 33.8
MW-11 6/21/2005 364 58.7 31
MW-11 9/22/2005 378 50.7 33
MW-11 12/13/2005 375 61 .2 36
MW-11 3/21/2006 381 55.2 33
MW-11 6/20/2006 374 62.1 31
MW-11 9/13/2006 380 51.1 29
MW-11 10/25/2006 378 67.9 32
MW-11 3/15/2007 375 69.2 31
MW-11 8/21/2007 383 39.2 30
MW-11 10/30/2007 378 40.3 29
MW-11 3/18/2008 380 38.1 29
MW-11 6/16/2008 356 40.8 30
MW-11 8/5/2008 380 40.6 29
MW-11 11/10/2008 351 42.4 30
MW-11 2/16/2009 356 44.4 29
MW-11 5/17/2009 366 36 26
MW-11 8/31/2009 374 41.9 26
MW-11 10/19/2009 389 41.8 30
MW-11 2/10/2010 410 67 33
MW-11 4/28/2010 387 75.9 32
MW-11 9/8/2010 410 70 31
MW-11 11 /11/2010 387 68 34
MW-11 2/2/2011 385 70.6 32
MW-11 4/4/2011 387 78.2 31
MW-11 8/3/2011 347 59.4 31
MW-11 10/4/2011 363 59.4 28
MW-11 2/13/2012 360 75 31
MW-11 5/8/2012 376 63.7 30
MW-11 7/11/2012 374 66.5 39
MW-11 11/12/2012 372.1 69.3 30
MW-11 2/20/2013 380.64 66.1 33.7
MW-11 5/14/2013 409.92 59.6 30.1
MW-11 7/10/2013 401 .38 61 .9 29
MW-11 11/19/2013 373.32 69.5 31.3
MW-11 3/11/2014 367.22 66.5 32.6
MW-11 6/3/2014 417.24 79.5 32.9
MW-11 9/8/2014 475.8 36.8 31
MW-11 11/17/2014 323.3 60.4 27.4
MW-11 2/3/2015 373.32 61 31
MW-11 4/8/2015 384.3 81.7 32.5
MW-11 8/10/2015 402.6 69.7 37.3
MW-11 11/11/2015 378.2 60.9 30.6
MW-11 2/8/2016 390.4 100 34
MW-11 5/3/2016 369.66 75.6 30.7
MW-11 8/16/2016 363.56 70.5 33.9
MW-11 11/7/2016 375.76 92.7 35.1
MW-11 2/8/2017 367.22 71.9 31.5
MW-11 5/2/2017 363.56 74.6 33.3
MW-11 8/15/2017 373.32 81 .6 32.7
MW-11 11/7/2017 380.64 73.5 31.9
MW-11 2/20/2018 381.86 61 .7 31.9
MW-11 4/18/2018 373.32 80 34
'\[ PP enOIXA
Source Assessment Report for MW-11 and MW-37
White Mesa Uranium Mill
' - --I
I Potassium Magnesium Sodium Sulfate Measured Calculated , Ratio (mg/L) (mg/L) (mg/L) (mg/L) TDS (mg/L) , TDS (mg/L)
[ __ I - --- - - - ---------------
5.7 8.8 550 926 1812 1950 108%
4.7 7.7 530 943 1728 1906 110%
5.0 6.7 540 922 1697 1930 114%
5.0 7 530 920 1700 1853 109%
7.6 30.6 487 1140 2130 2179 102%
7.9 25.4 574 1150 2100 2258 108%
7.4 30 540 1160 1850 2234 121%
6.3 18.2 544 1090 1950 2112 108%
6.3 15.3 551 968 1930 2002 104%
6.8 19.3 544 1070 1930 2112 109%
6.2 16.8 551 1120 1920 2163 113%
7.3 20.1 554 1150 2000 2199 110%
6.7 14.9 558 1060 1910 2100 110%
7.2 21.7 559 1200 1860 2266 122%
7.6 22.1 571 1120 2040 2196 108%
6.2 10.9 668 1060 1800 2197 122%
7.5 11 .1 580 1020 1770 2066 117%
6.0 10 606 1040 1750 2109 121%
6.1 10.7 632 1050 1790 2126 119%
6.0 10.6 631 1060 1780 2157 121%
6.2 11 655 1100 1830 2196 120%
6.3 12.4 581 977 1910 2006 105%
5.9 10 548 1060 1850 2052 111%
6.1 11.2 602 1090 1840 2151 117%
6.0 11.4 641 1040 1830 2159 118%
6.8 19.7 567 1140 2040 2244 110%
7.1 23.1 642 1150 2040 2317 114%
7.0 20.9 614 1140 1960 2293 117%
6.9 20.1 573 1180 2020 2269 112%
6.8 21.2 601 1190 1980 2307 116%
7.3 23.4 622 1140 2070 2289 111%
6.6 17.3 628 1090 1940 2179 112%
6.5 17.3 580 1140 1930 2194 114%
6.9 22.9 626 1160 2090 2282 109%
7.0 19.3 517 1090 2040 2103 103%
7.4 19.6 618 1080 2020 2205 109%
7.0 21.4 562 1110 2050 2172 106%
7.2 19.6 578 1080 1970 2165 110%
6.5 18.3 563 763 1820 1850 102%
6.6 20.1 538 1240 2010 2297 114%
6.3 21 .2 547 1050 1980 2099 106%
6.7 21.7 540 904 1940 1939 100%
6.7 24.9 580 1140 1990 2281 115%
6.0 10.9 542 1030 1930 2133 110%
6.2 18 643 1140 1840 2218 121%
6.8 19.9 576 1110 1880 2178 116%
7.0 26.3 621 1170 2010 2323 116%
6.8 21 554 1050 1960 2141 109%
5.9 18.3 554 1220 1790 2268 127%
7.0 31.8 582 1160 2090 2305 110%
7.0 23.8 613 1200 2000 2320 116%
7.1 22.2 608 1160 2070 2265 109%
7.1 29.2 537 1290 2100 2367 113%
7.6 22.9 608 1050 1920 2159 112%
6.9 25.1 568 1140 1970 2211 112%
7.0 26 595 1360 1990 2476 124%
6.7 23.1 575 1060 2020 2151 106%
6.5 18.1 583 1120 1880 2203 117%
7.2 26.3 567 1110 1980 2198 111%
Page 2 of 20 ~¾4-INTERA
Appendix A-2: Comparison of Calculated and Measured TDS in MW-11 and MW-37
I
Alkalinity Calcium Chloride Well Date Sampled (mg/Las
HCO,) (mg/L} (mg/L)
- ---~-
MW-11 9/11/2018 373.32 85.5 36.4
MW-11 10/25/2018 424.56 90.2 29.3
MW-11 1/15/2019 392.84 97.9 32
MW-11 4/24/2019 385.52 83.4 34
MW-11 7/16/2019 375.76 113 48.4
MW-11 10/15/2019 458.72 87.9 30.8
MW-11 1/15/2020 378.2 85.6 38.9
MW-11 4/8/2020 341.6 101 38.3
MW-11 7/7/2020 319.64 95.8 42.1
MW-11 10/12/2020 358.68 104 44.8
MW-11 1/12/2021 346.48 102 46.4
MW-11 4/20/2021 375.76 118 47.7
MW-11 7/27/2021 390.4 178 48.3
MW-11 10/20/2021 451.4 149 52.8
MW-11 1/18/2022 331.84 109 51.1
MW-11 4/18/2022 325.74 106 54.9
MW-11 7/12/2022 337.94 152 54
MW-11 10/10/2022 330.62 150 72.1
MW-11 1/25/2023 302.56 133 70.7
MW-11 4/17/2023 331 .84 155 70.6
MW-37 8/11/2011 291 457 55
MW-37 10/19/2011 261 481 50
MW-37 2/29/2012 297 482 36
MW-37 5/29/2012 264 479 50
MW-37 7/30/2012 265 486 51
MW-37 12/5/2012 282 454 46.6
MW-37 3/20/2013 256 487 44.5
MW-37 6/3/2013 261 492 48.8
MW-37 7/23/2013 257 467 43.2
MW-37 12/18/2013 235 475 46.1
MW-37 3/20/2014 254 445 45.1
MW-37 6/18/2014 266 468 45.1
MW-37 9/17/2014 296 403 44
MW-37 12/3/2014 273 438 39.9
MW-37 3/5/2015 163 469 46.9
MW-37 6/24/2015 267 453 46.4
MW-37 8/11/2015 239 482 53.3
MW-37 12/9/2015 239 489 47.2
MW-37 3/22/2016 121 498 42.7
MW-37 5/18/2016 189 439 49.4
MW-37 9/21/2016 227 467 46.4
MW-37 11/16/2016 224 470 49.5
MW-37 3/7/2017 205 468 45.7
MW-37 5/25/2017 234 434 47.3
MW-37 9/25/2017 155 425 46.5
MW-37 11/8/2017 218 460 46.3
MW-37 5/3/2018 235 485 50.5
MW-37 10/30/2018 234 515 42.1
MW-37 5/15/2019 283 527 48.7
MW-37 11/22/2019 287 467 44.3
MW-37 4/21/2020 259 508 45
MW-37 10/27/2020 249 454 43.1
MW-37 5/12/2021 256 458 44.5
MW-37 11/17/2021 244 479 44.4
MW-37 5/17/2022 212 476 46.4
MW-37 11/1/2022 215 466 44.2
MW-37 5/11/2023 204 436 45.2
Appendix A
Source Assessment Report for MW-11 and MW-37
White Mesa Uranium Mill
-.
I ' Calculated I Potassium Magnesium Sodium I Sulfate Measured Ratio (mg/L} (mg/L) (mg/L) (mg/L) TDS (mg/L) TDS (mg/L}
-------I -----
7.1 27 665 1160 1960 2354 120%
7.2 26.9 670 1190 1880 2438 130%
7.3 30.1 658 1150 2040 2368 116%
7.3 27.1 608 1160 1890 2305 122%
8.0 38 641 1410 1890 2634 139%
8.0 27.2 525 1290 2100 2428 116%
7.8 28.2 572 1180 1920 2291 119%
8.8 32.9 639 1180 1920 2342 122%
7.7 30.7 666 1260 2590 2422 94%
7.1 34.1 555 1300 992 2404 242%
7.6 33.4 562 1140 2010 2238 111%
7.9 38.1 579 1290 2110 2456 116%
10.6 62.1 520 1470 2680 2679 100%
10.7 49.8 508 1360 2200 2582 117%
9.3 34.8 513 1020 2050 2069 101%
7.0 37.5 451 1240 2060 2222 108%
7.3 55.1 440 1390 2520 2436 97%
7.8 51 500 1140 2570 2252 88%
7.3 44.5 467 1240 2390 2265 95%
7.9 53.6 464 1330 2450 2413 98%
13.9 129 556 2440 3820 3942 103%
14.2 133 556 2620 3980 4115 103%
15.2 132 554 2500 3900 4016 103%
16.3 140 595 2460 4000 4004 100%
15.1 133 575 2700 4090 4225 103%
14.2 131 514 1010 3830 2452 64%
14.7 139 546 2130 3770 3617 96%
15.2 137 522 2570 3700 4046 109%
14.4 123 478 2720 3890 4103 105%
14.6 132 512 2750 3950 4165 105%
14.3 130 476 2600 4000 3964 99%
16.3 141 527 2640 3860 4103 106%
14.3 121 493 2370 3850 3742 97%
16.0 128 461 2700 3880 4056 105%
16.6 124 502 2650 3870 3972 103%
15.8 131 536 2650 3920 4099 105%
16.1 128 507 2480 3770 3906 104%
14.6 130 497 2600 3910 4017 103%
15.1 129 538 2360 3880 3704 95%
15.7 120 468 2530 3630 3811 105%
16.1 135 527 2300 4000 3718 93%
17.8 134 528 2600 3730 4024 108%
16.4 131 513 2240 3830 3619 94%
15.2 123 470 2430 3860 3754 97%
17.7 123 473 2350 3850 3590 93%
16.3 132 490 2360 3680 3723 101%
15.4 132 523 2570 3100 4011 129%
17.9 142 571 2170 3470 3692 106%
17.4 146 567 2330 3890 3919 101%
16.2 131 506 2640 3680 4091 111%
16.0 145 565 2510 3880 4048 104%
15.0 125 523 2460 3950 3869 98%
17.5 127 484 2570 4250 3957 93%
18.8 129 502 2560 4040 3977 98%
15.5 135 521 2340 3660 3746 102%
14.8 132 482 2280 4000 3634 91%
14.6 121 442 2580 3940 3843 98%
Page 3 of 20 ~2:#=INTERA
Appendix A-3: Charge Balance Calculations for Major Cations and Anions in MW-11 and MW-
37
I I
Well Date Calcium Sodium Magnesiu
(meq/L) (meq/L) m (meq/L)
,_ __ , __ -•-· --~-~---·
MW-11 12/16/1982 1.80 23.92 0.72
MW-11 5/24/1983 1.55 23.05 0.63
MW-11 10/26/1983 1.40 23.49 0.55
MW-11 6/12/1984 1.45 23.05 0.58
MW-11 11/27/2000 4.69 21.18 2.52
MW-11 11/6/2001 4.14 24.97 2.09
MW-11 9/10/2002 4.53 23.49 2.47
MW-11 6/21/2005 2.93 23.66 1.50
MW-11 9/22/2005 2.53 23.97 1.26
MW-11 12/13/2005 3.05 23.66 1.59
MW-11 3/21/2006 2.75 23.97 1.38
MW-11 6/20/2006 3.10 24.10 1.65
MW-11 9/13/2006 2.55 24.27 1.23
MW-11 10/25/2006 3.39 24.31 1.79
MW-11 3/15/2007 3.45 24.84 1.82
MW-11 8/21/2007 1.96 29.06 0.90
MW-11 10/30/2007 2.01 25.23 0.91
MW-11 3/18/2008 1.90 26.36 0.82
MW-11 6/16/2008 2.04 27.49 0.88
MW-11 8/5/2008 2.03 27.45 0.87
MW-11 11/10/2008 2.12 28.49 0.90
MW-11 2/16/2009 2.22 25.27 1.02
MW-11 5/17/2009 1.80 23.84 0.82
MW-11 8/31/2009 2.09 26.19 0.92
MW-11 10/19/2009 2.09 27.88 0.94
MW-11 2/10/2010 3.34 24.66 1.62
MW-11 4/28/2010 3.79 27.93 1.90
MW-11 9/8/2010 3.49 26.71 1.72
MW-11 11/11/2010 3.39 24.92 1.65
MW-11 2/2/2011 3.52 26.14 1.74
MW-11 4/4/2011 3.90 27.06 1.93
MW-11 8/3/2011 2.96 27.32 1.42
MW-11 10/4/2011 2.96 25.23 1.42
MW-11 2/13/2012 3.74 27.23 1.88
MW-11 5/8/2012 3.18 22.49 1.59
MW-11 7/11/2012 3.32 26.88 1.61
MW-11 11/12/2012 3.46 24.45 1.76
MW-11 2/20/2013 3.30 25.14 1.61
MW-11 5/14/2013 2.97 24.49 1.51
MW-11 7/10/2013 3.09 23.40 1.65
MW-11 11/19/2013 3.47 23.79 1.74
MW-11 3/11/2014 3.32 23.49 1.79
MW-11 6/3/2014 3.97 25.23 2.05
MW-11 9/8/2014 1.84 23.58 0.90
MW-11 11/17/2014 3.01 27.97 1.48
MW-11 2/3/2015 3.04 25.05 1.64
MW-11 4/8/2015 4.08 27.01 2.16
Appendix A
Source Assessment Report for MW-11 and MW-37
White Mesa Uranium Mill
-Total Total
Potassium Cation HCO3 Chloride so. Anion j Charge Balance I (meq/L) Charge (meq/L) (meq/L) (meq/L) Charge I Error
___ (m_!!q/L) ·-_ -·--_ {meq/L) l_ --0.15 26.59 -6.54 -0.69 -19.28 -26.51 0.16%
0.12 25.35 -5.95 -0.76 -19.63 -26.34 -1.90%
0.13 25.56 -6.59 -0.73 -19.20 -26.52 -1.83%
0.13 25.20 -5.41 -0.90 -19.15 -25.47 -0.52%
0.19 28.59 -6.26 -1.05 -23.74 -31.05 -4.13%
0.20 31.40 -6.15 -1.20 -23 .94 -31.28 0.18%
0.19 30.68 -6.10 -0.95 -24.15 -31.20 -0.85%
0.16 28.25 -5.97 -0.87 -22.69 -29.53 -2.22%
0.1 6 27.92 -6.19 -0.93 -20.15 -27.28 1.15%
0.17 28.48 -6.15 -1.02 -22.28 -29.44 -1.66%
0.16 28.26 -6.24 -0.93 -23.32 -30.49 -3.80%
0.19 29.04 -6.13 -0.87 -23.94 -30.95 -3.18%
0.17 28.22 -6.23 -0.82 -22.07 -29.12 -1 .56%
0.18 29.67 -6.19 -0.90 -24.98 -32.08 -3.90%
0.19 30.30 -6.15 -0.87 -23.32 -30.34 -0.06%
0.16 32.07 -6.28 -0.85 -22.07 -29.19 4.69%
0.19 28.34 -6.19 -0.82 -21.24 -28.25 0.17%
0.15 29.24 -6.23 -0.82 -21 .65 -28.70 0.93%
0.16 30.56 -5.83 -0.85 -21.86 -28.54 3.42%
0.15 30.50 -6.23 -0.82 -22.07 -29.12 2.32%
0.16 31.67 -5.75 -0.85 -22.90 -29.50 3.55%
0.16 28.67 -5.83 -0.82 -20.34 -26.99 3.01%
0.15 26.61 -6.00 -0.73 -22.07 -28.80 -3.96%
0.16 29.35 -6.13 -0.73 -22.69 -29.56 -0.34%
0.15 31.06 -6.37 -0.85 -21 .65 -28.87 3.64%
0.17 29.80 -6.72 -0.93 -23.74 -31.39 -2.59%
0.18 33.80 -6.34 -0.90 -23.94 -31.19 4.01%
0.18 32.10 -6.72 -0.87 -23.74 -31.33 1.21%
0.18 30.15 -6.34 -0.96 -24.57 -31.87 -2.78%
0.17 31.58 -6.31 -0.90 -24.78 -31.99 -0.64%
0.19 33.07 -6.34 -0.87 -23.74 -30.95 3.31%
0.17 31.87 -5.69 -0.87 -22.69 -29.26 4.28%
0.17 29.78 -5.95 -0.79 -23.74 -30.47 -1.15%
0.18 33.03 -5.90 -0.87 -24.15 -30.93 3.29%
0.18 27.43 -6.16 -0.85 -22.69 -29.70 -3.97%
0.19 32.00 -6.13 -1.10 -22.49 -29.72 3.70%
0.18 29.84 -6.10 -0.85 -23.11 -30.05 -0.35%
0.18 30.24 -6.24 -0.95 -22.49 -29.67 0.94%
0.17 29.14 -6.72 -0.85 -15.89 -23.45 10.81%
0.17 28.31 -6.58 -0.82 -25.82 -33.21 -7.97%
0.16 29.17 -6.12 -0.88 -21.86 -28.86 0.52%
0.17 28.76 -6.02 -0.92 -18.82 -25.76 5.51%
0.17 31.42 -6.84 -0.93 -23.74 -31.50 -0.14%
0.15 26.46 -7.80 -0.87 -21.44 -30.12 -6.46%
0.16 32.62 -5.30 -0.77 -23.74 -29.81 4.51%
0.17 29.91 -6.12 -0.87 -23.11 -30.10 -0.32%
0.18 33.43 -6.30 -0.92 -24.36 -31.57 2.86%
Page 4 of 20 ~crni •NTERA
Appendix A-3: Charge Balance Calculations for Major Cations and Anions in MW-11 and MW-
37
,-I -, --Total
Well Date • Calcium Sodium Magnesiu Potassium Cation
I (meq/L) (meq/L) m (meq/Ll (meq/L) Charge
I L ------·----------- -{meq/L}
MW-11 8/10/2015 3.48 24.10 1.73
MW-11 11/11/2015 3.04 24.10 1.51
MW-11 2/8/2016 4.99 25.32 2.62
MW-11 5/3/2016 3.77 26.66 1.96
MW-11 8/16/2016 3.52 26.45 1.83
MW-11 11/7/2016 4.63 23.36 2.40
MW-11 2/8/2017 3.59 26.45 1.88
MW-11 5/2/2017 3.72 24.71 2.06
MW-11 8/15/2017 4.07 25.88 2.14
MW-11 11/7/2017 3.67 25.01 1.90
MW-11 2/20/2018 3.08 25.36 1.49
MW-11 4/18/2018 3.99 24.66 2.16
MW-11 9/11/2018 4.27 28.93 2.22
MW-11 10/25/2018 4.50 29.14 2.21
MW-11 1/15/2019 4.89 28.62 2.48
MW-11 4/24/2019 4.16 26.45 2.23
MW-11 7/16/2019 5.64 27.88 3.13
MW-11 10/15/2019 4.39 22.84 2.24
MW-11 1/15/2020 4.27 24.88 2.32
MW-11 4/8/2020 5.04 27.79 2.71
MW-11 7/7/2020 4.78 28.97 2.53
MW-11 10/12/2020 5.19 24.14 2.81
MW-11 1/12/2021 5.09 24.45 2.75
MW-11 4/20/2021 5.89 25.18 3.13
MW-11 7/27/2021 8.88 22.62 5.11
MW-11 10/20/2021 7.44 22.10 4.10
MW-11 1/18/2022 5.44 22.31 2.86
MW-11 4/18/2022 5.29 19.62 3.09
MW-11 7/12/2022 7.58 19.14 4.53
MW-11 10/10/2022 7.49 21.75 4.20
MW-11 1/25/2023 6.64 20.31 3.66
MW-11 4/17/2023 7.73 20.18 4.41
MW-37 8/11/2011 22.80 24.18 10.61
MW-37 10/19/2011 24.00 24.18 10.94
MW-37 2/29/2012 24.05 24.10 10.86
MW-37 5/29/2012 23.90 25.88 11 .52
MW-37 7/30/2012 24.25 25.01 10.94
MW-37 12/5/2012 22.65 22.36 10.78
MW-37 3/20/2013 24.30 23.75 11.44
MW-37 6/3/2013 24.55 22.71 11.27
MW-37 7/23/2013 23.30 20.79 10.12
MW-37 12/18/2013 23.70 22.27 10.86
MW-37 3/20/2014 22.21 20.70 10.70
MW-37 6/18/2014 23.35 22.92 11.60
MW-37 9/17/2014 20.11 21.44 9.95
MW-37 12/3/2014 21.86 20.05 10.53
MW-37 3/5/2015 23.40 21.84 10.20
Appendix A
Source Assessment Report for MW-11 and MW-37
White Mesa Uranium Mill
0.17 29.48
0.15 28.79
0.18 33.10
0.18 32.57
0.18 31.97
0.18 30.57
0.19 32.11
0.18 30.67
0.18 32.27
0.17 30.75
0.17 30.09
0.18 31.00
0.18 35.59
0.18 36.04
0.19 36.17
0.19 33.02
0.21 36.85
0.20 29.66
0.20 31.67
0.23 35.77
0.20 36.47
0.18 32.32
0.19 32.48
0.20 34.41
0.27 36.88
0.27 33.90
0.24 30.85
0.18 28.17
0.19 31.44
0.20 33.63
0.19 30.80
0.20 32.53
0.36 57.96
0.36 59.49
0.39 59.40
0.42 61.72
0.39 60.59
0.36 56.15
0.38 59.86
0.39 58.92
0.37 54.58
0.37 57.21
0.37 53.97
0.42 58.29
0.37 51.87
0.41 52.85
0.42 55.86
Page 5 of 20
I Total
HCO3 Chloride I SO4 Anion Charge Balance
(meq/L) (meq/L) 1 (meq/L) Charge Error
-----_ . _____ (me_q/LL -
-6.60 -1.05 -21.86 -29.51 -0.06%
-6.20 -0.86 -25.40 -32.46 -5.99%
-6.40 -0.96 -24.15 -31.51 2.46%
-6.06 -0.87 -24.98 -31.91 1.03%
-5.96 -0.96 -24.15 -31.07 1.44%
-6.16 -0.99 -26.86 -34.01 -5.32%
-6.02 -0.89 -21.86 -28.77 5.49%
-5.96 -0.94 -23.74 -30.63 0.06%
-6.12 -0.92 -28.32 -35.36 -4.56%
-6.24 -0.90 -22.07 -29.21 2.57%
-6.26 -0.90 -23.32 -30.48 -0.63%
-6.12 -0.96 -23.11 -30.19 1.33%
-6.12 -1.03 -24.15 -31.30 6.43%
-6.96 -0.83 -24.78 -32.56 5.07%
-6.44 -0.90 -23 .94 -31.28 7.24%
-6.32 -0.96 -24.15 -31.43 2.47%
-6.16 -1.37 -29.36 -36.88 -0.04%
-7.52 -0.87 -26.86 -35.24 -8.60%
-6.20 -1.10 -24.57 -31.86 -0.30%
-5.60 -1.08 -24.57 -31.25 6.75%
-5.24 -1.19 -26.23 -32.66 5.52%
-5.88 -1.26 -27.07 -34.21 -2.84%
-5.68 -1.31 -23.74 -30.72 2.78%
-6.16 -1.35 -26.86 -34.36 0.07%
-6.40 -1.36 -30.61 -38.37 -1.97%
-7.40 -1.49 -28.32 -37.20 -4.64%
-5.44 -1.44 -21.24 -28.12 4.64%
-5.34 -1 .55 -25.82 -32.70 -7.45%
-5.54 -1.52 -28.94 -36.00 -6.76%
-5.42 -2.03 -23.74 -31.19 3.77%
-4.96 -1 .99 -25.82 -32.77 -3.10%
-5.44 -1 .99 -27.69 -35.12 -3.83%
-4.77 -1.55 -50.80 -57.12 0.73%
-4.28 -1.41 -54.55 -60.24 -0.62%
-4.87 -1.02 -52.05 -57.93 1.25%
-4.33 -1.41 -51.22 -56.95 4.01%
-4.34 -1.44 -56.21 -62.00 -1.15%
-4.62 -1.31 -21.03 -26.96 35.12%
-4.20 -1.26 -44.35 -49.80 9.17%
-4.28 -1.38 -53.51 -59.16 -0.21%
-4.22 -1.22 -56.63 -62.07 -6.42%
-3.86 -1.30 -57.26 -62.42 -4.35%
-4.16 -1.27 -54.13 -59.56 -4.93%
-4.36 -1.27 -54.97 -60.60 -1.94%
-4.86 -1.24 -49.34 -55.44 -3.33%
-4.48 -1.13 -56.21 -61.82 -7.82%
-2.68 -1.32 -55.17 -59.18 -2.88%
--S.INTERA
Appendix A-3: Charge Balance Calculations for Major Cations and Anions in MW-11 and MW-
37
-- -Total
I Calcium Sodium Magnesiu Potassium Cation Well Date (meq/L) 1 (meq/L) m (meq/L) (meq/L) Charge l ---~------
MW-37 6/24/2015 22.60
MW-37 8/11/2015 24.05
MW-37 12/9/2015 24.40
MW-37 3/22/2016 24.85
MW-37 5/18/2016 21.91
MW-37 9/21/2016 23.30
MW-37 11/16/2016 23.45
MW-37 3/7/2017 23.35
MW-37 5/25/2017 21.66
MW-37 9/25/2017 21.21
MW-37 11/8/2017 22.95
MW-37 5/3/2018 24.20
MW-37 10/30/2018 25.70
MW-37 5/15/2019 26.30
MW-37 11/22/2019 23.30
MW-37 4/21/2020 25.35
MW-37 10/27/2020 22.65
MW-37 5/12/2021 22.85
MW-37 11/17/2021 23.90
MW-37 5/17/2022 23.75
MW-37 11/1/2022 23.25
MW-37 5/11/2023 21.76
meq/L= milliequivalent per liter
HCO3 = Bicarbonate
SO4 = Sulfate
Appendix A
23.31
22.05
21.62
23.40
20.36
22.92
22.97
22.31
20.44
20.57
21.31
22.75
24.84
24.66
22.01
24.58
22.75
21.05
21.84
22.66
20.97
19.23
----10.78
10.53
10.70
10.61
9.87
11 .11
11.02
10.78
10.12
10.12
10.86
10.86
11.68
12.01
10.78
11.93
10.28
10.45
10.61
11.11
10.86
9.95
Source Assessment Report for MW-11 and MW-37
White Mesa Uranium Mill
. __ ~ . _ (me_qLLJ
0.40 57.10
0.41 57.05
0.37 57.09
0.39 59.25
0.40 52.54
0.41 57.74
0.46 57.90
0.42 56.86
0.39 52.61
0.45 52.35
0.42 55.54
0.39 58.20
0.46 62.68
0.45 63.42
0.41 56.50
0.41 62.26
0.38 56.07
0.45 54.80
0.48 56.83
0.40 57.92
0.38 55.46
0.37 51.31
Page 6 of 20
Total
I Charge Balance HCO3 Chloride SO4 Anion
(meq/L) (meq/L) (meq/L) Charge Error
--_ .. __ ~~ __ (meq[L,} ----
-4.38 -1.31 -55.17 -60.86 -3.19%
-3.92 -1.50 -51.63 -57.06 -0.01%
-3.92 -1.33 -54.13 -59.38 -1.97%
-1.98 -1.20 -49.14 -52.32 6.21%
-3.10 -1.39 -52.68 -57.17 -4.22%
-3.72 -1.31 -47.89 -52.91 4.37%
-3.68 -1.40 -54.13 -59.21 -1.12%
-3.36 -1.29 -46.64 -51.29 5.16%
-3.84 -1.33 -50.59 -55.77 -2.91%
-2.54 -1.31 -48.93 -52.78 -0.40%
-3.58 -1.31 -49.14 -54.02 1.39%
-3.86 -1.42 -53.51 -58.79 -0.50%
-3.84 -1.19 -45.18 -50.21 11.05%
-4.64 -1.37 -48.51 -54.52 7.54%
-4.70 -1.25 -54.97 -60.91 -3.75%
-4.24 -1.27 -52.26 -57.77 3.75%
-4.08 -1.22 -51.22 -56.51 -0.39%
-4.20 -1.26 -53.51 -58.96 -3.66%
-4.00 -1.25 -53.30 -58.55 -1.49%
-3.48 -1.31 -48.72 -53.51 3.96%
-3.52 -1.25 -47.47 -52.24 2.99%
-3.34 -1 .28 -53.72 -58.33 -6.40%
~S-INTERA
Appendix A-5: MW-11 and MW-37 Data Used for Analysis
I -
Well Date Sampled
•---·-
MW-11 5/24/1983
MW-11 6/12/1984
MW-11 6/28/1985
MW-11 3/27/1986
MW-11 12/10/1986
MW-11 2/20/1987
MW-11 2/20/1987
MW-11 4/29/1987
MW-11 11/20/1987
MW-11 8/24/1988
MW-11 11/2/1988
MW-11 6/22/1989
MW-11 8/25/1989
MW-11 11/17/1989
MW-11 5/8/1990
MW-11 11/13/1990
MW-11 2/28/1991
MW-11 9/24/1991
MW-11 3/17/1992
MW-11 9/15/1992
MW-11 3/30/1993
MW-11 9/29/1993
MW-11 3/30/1994
MW-11 3/30/1994
MW-11 8/23/1994
MW-11 3/14/1995
MW-11 6/27/1995
MW-11 12/7/1995
MW-11 6/6/1996
MW-11 11/22/1996
MW-11 5/11/1999
MW-11 11/6/2001
MW-11 9/10/2002
MW-11 9/10/2002
MW-11 3/30/2005
MW-11 3/30/2005
MW-11 6/21/2005
MW-11 6/21/2005
MW-11 9/22/2005
MW-11 9/22/2005
MW-11 12/13/2005
MW-11 12/13/2005
MW-11 3/21/2006
MW-11 6/20/2006
MW-11 6/20/2006
Appendix A
Source Assessment Report for MW-11 and MW-37
White Mesa Uranium Mill
--
Parameter Name
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Page 8 of 20
Report
Result Report Units Qualifier
-------~-----
10.0 ug/I u
5.0 ug/I u
1.0 ug/I u
1.0 ug/I u
2.0 ug/I u
3.0 ug/1
4.0 ug/1
1.0 ug/I u
20.0 ug/1
1.0 ug/I
29.0 ug/I
4.0 ug/I
2.0 ug/I u
20.0 ug/I
1.0 ug/I u
1.0 ug/I u
2.0 ug/I u
2.0 ug/I u
2.0 ug/1 u
2.0 ug/I u
2.0 ug/I u
2.0 ug/I u
2.0 ug/I u
2.0 ug/I u
4.0 ug/I
2.0 ug/1 u
10.0 ug/I u
2.0 ug/1 u
3.0 ug/1
1.0 ug/I u
2.0 ug/I
3.0 ug/I
3.0 ug/I
2.8 ug/I
5.0 ug/I J
5.0 ug/I J
5.0 ug/I u
5.0 ug/1 u
5.0 ug/I u
5.0 ug/I u
5.0 ug/1 u
5.0 ug/I u
5.0 ug/I u
5.0 ug/I u
5.0 ug/I u
~-¥s •NTERA
Appendix A-5: MW-11 and MW-37 Data Used for Analysis
I Well Date Sampled i l --
MW-11 9/13/2006
MW-11 10/25/2006
MW-11 3/15/2007
MW-11 8/21/2007
MW-11 10/30/2007
MW-11 3/18/2008
MW-11 6/16/2008
MW-11 8/5/2008
MW-11 11/10/2008
MW-11 2/16/2009
MW-11 5/17/2009
MW-11 8/31/2009
MW-11 10/19/2009
MW-11 2/10/2010
MW-11 4/28/2010
MW-11 9/8/2010
MW-11 11/11/2010
MW-11 2/2/2011
MW-11 4/4/2011
MW-11 8/3/2011
MW-11 10/4/2011
MW-11 2/13/2012
MW-11 5/8/2012
MW-11 7/11/2012
MW-11 11/12/2012
MW-11 2/20/2013
MW-11 5/14/2013
MW-11 7/10/2013
MW-11 11/19/2013
MW-11 2/24/2014
MW-11 3/11/2014
MW-11 6/3/2014
MW-11 9/8/2014
MW-11 11/17/2014
MW-11 2/3/2015
MW-11 4/8/2015
MW-11 8/10/2015
MW-11 11/11/2015
MW-11 2/8/2016
MW-11 5/3/2016
MW-11 8/16/2016
MW-11 11/7/2016
MW-11 2/8/2017
MW-11 5/2/2017
MW-11 8/15/2017
Appendix A
Source Assessment Report for MW-11 and MW-37
White Mesa Uranium Mill
- -- -
Parameter Name Report Report Units Result -- -----
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/1
Selenium 5.0 ug/1
Selenium 5.0 ug/1
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/1
Selenium 5.0 ug/I
Selenium 5.0 ug/1
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Selenium 5.0 ug/I
Page 9 of 20
Qualifier
----u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
u
---94slNTERA
Appendix A-5: MW-11 and MW-37 Data Used for Analysis
,---
Well
I
Date Sampled . --~ -
MW-11 11/7/2017
MW-11 2/20/2018
MW-11 4/18/2018
MW-11 9/11/2018
MW-11 10/25/2018
MW-11 1/15/2019
MW-11 4/24/2019
MW-11 7/16/2019
MW-11 10/15/2019
MW-11 1/15/2020
MW-11 4/8/2020
MW-11 7/7/2020
MW-11 10/12/2020
MW-11 1/12/2021
MW-11 4/20/2021
MW-11 7/27/2021
MW-11 10/20/2021
MW-11 1/18/2022
MW-11 4/18/2022
MW-11 7/12/2022
MW-11 10/10/2022
MW-11 1/25/2023
MW-11 2/8/2023
MW-11 3/14/2023
MW-11 4/17/2023
MW-11 5/9/2023
MW-11 6/5/2023
MW-11 7/11/2023
MW-11 8/2/2023
MW-37 8/9/2011
MW-37 10/12/2011
MW-37 12/8/2011
MW-37 2/22/2012
MW-37 5/15/2012
MW-37 7/19/2012
MW-37 12/5/2012
MW-37 3/20/2013
MW-37 6/3/2013
MW-37 7/23/2013
MW-37 12/18/2013
MW-37 3/20/2014
MW-37 6/18/2014
MW-37 9/4/2014
MW-37 12/3/2014
MW-37 3/5/2015
MW-37 5/27/2015 Appendix A
Source Assessment Report for MW-11 and MW-37
White Mesa Uranium Mill
Parameter Name
- -----
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
Selenium
pH
pH
pH
pH
pH
pH
pH
pH
pH
pH
pH
pH
pH
pH
pH
pH
pH
Page 10 of 20
I I Report
1 Report Units Qualifier Result --~--·--------·
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
5.0 ug/1 u
6.8 ug/1
9.3 ug/1
10.8 ug/1
9.3 ug/1
15.5 ug/1
17.5 ug/1
17.7 ug/1
14.9 ug/1
14.2 ug/1
16.8 ug/1
15.3 ug/1
17.1 ug/1
22.0 ug/1
6.86 pH Units
6.89 pH Units
6.73 pH Units
6.68 pH Units
6.65 pH Units
6.9 pH Units
7.04 pH Units
6.86 pH Units
7.01 pH Units
6.9 pH Units
6.94 pH Units
6.76 pH Units
6.65 pH Units
6.7 pH Units
6.75 pH Units
6.61 pH Units
6.82 pH Units
~::slNTERA
Appendix A-6: Extreme Outliers Removed from Analysis
Reason Location ID Date Sampled , Parameter Name Report Result Report Units
•----------,_ -•------~---~ _ ______J
No extreme outliers for SAR parameters removed from anal sis
Appendix A
Source Assesment Report for MW-11 and MW-37
White Mesa Uranium Mill Page 12 of 20 P!-2¥s1NTERA
Appendix A-7: Box Plots of MW-11 and MW-37
_ __ ~ __ _ _ __ p_H in M\fY-37 for AIIJ)~ta ___ I
7.0
-;;;-6.8 ~
C: ::::,
:r: 6.6 a. -:r: 6.4 a.
6.2
Appendix A
pH in MW-37
0
0
Percent nondetect: 0%
o Outlier
♦ Extreme
Min: 6.05, Mean: 6.74, Max: 7.13, Std Dev: 0.25
Upper extreme threshold (Q75 + 3xH): 7.68
Lower extreme threshold (Q25 -3xH): 5.8775
Source Assessment Report for MW-11 and MW-37 ~%s1NTERA White Mesa Uranium Mill Page 14 of 20
~ en ► :::r OU -·CU .--, CD CD n ::::s :::,,, CD C.. ::.. ):> -· CD X gi g: ):>
CD C en -, en ~ 3 -· CD C ::I 3 .-+
s:: ~ =u -o
-0 DJ Dtl n,
I-" V1
0 .....
N 0
;::i.
a' -, s:: ~ ...... ......
Ill ::I c.. s:: ~ c,J -.J
fl
2 -I
I
):> z =o Dl ,.
< ~ Dl
ii> C" ro
a. Dl ..... Dl
C: en CD a. s· MW-01 -
C" MW-02 -0 X MW-03A -
"Q. MW-05 -0 -MW-11 -en
MW-12 -
MW-14 -
MW-15 -
MW-17 -
MW-18 -
MW-19 -
MW-20 -
MW-22 -
MW-23 -
MW-24 -
MW-25 -
MW-26 -
MW-27 -
MW-28 -
MW-29 -
MW-30 -
MW-31 -
MW-32 -
MW-34 -
MW-35 -
MW-36 -
MW-37 -
MW-38 -
MW-39 -
MW-40 -
Selenium (ug/L)
...... ...... N N (,.) 01 0 01 0 01 0 0 0 0 0 0 0 0
I I I I I I I
1)-i -· i[)]-i> 0
• c--[IJ----, o • Oo-• ... OJ---, ..
-c-------CD----, • t(]" • • ◄<>
♦ lfl!o•
♦ ..
I ...
t
l]-i!>
►
c[]--,o
c-ffi-i
♦
fl&
f{l]-.PO
c-{0---l 0
fP • 0
c-[]-" rn o I ~c -, !::!:.
~--····CD--i CD -· 3 ~ CD
(/)
(1)
iii" ::::, c·
3
)>
"C
"C (D ::s C. -· ><
)>
I 00 ..
m 0 ><
""C -0 in
o' .,
CJ)
)> ;o
""C D) .,
D)
3
(D -(D .,
(/J -::s
G) .,
0 C: ::s
C. ~ D) -(D .,
s:
0 ::s ;:;:
0
:::!. ::s cc :e (D -(/J
APPENDIXB
Appendix B-1: Summary of Statistical Analysis for Indicator Parameters in MW-11 and MW-37
Well Data Set Constituent N
I ALL 2023 SAR Data I I Chloride (mg/L) ~
GWCL Subset Post 2019 Chloride (mg/L) 47
ALL 2023 SAR Data Fluoride (mg/L) 81
MW-11 GWCL Subset Post 2019 Fluoride (mg/L) 17
ALL 2023 SAR Data Sulfate (mg/L) 181
GWCL Subset Post 2019 Sulfate (mg/L) 47
ALL 2023 SAR Data Uranium (µg/L) 150
GWCL Subset Post 2019 Uranium (µg/L) 17
ALL 2023 SAR Data Chloride (mg/L) 37
Al I ?OJ~ c;AR n;it;i FlunrirtP fmnJI l ~7
¾Non-
Detected Mean
Values
OITI
0 52.1
0 0.47
0 0.34
0 1107.6
0 1240.7
19.3 0.9
0 1.8
0 46.3
!i4 n~
Standard
Deviation
12.3
0.1
0.1
184.6
124.3
0.7
0.7
3.5
n 1
Shapiro-WIik Test
for Normality
w p mmf
0.963 1.45E-01
0.932 3.40E-04
0.930 2.21E-01
0.542 1.38E-21
0.878 1.49E-04
0.580 5.97E-19
0.911 1.05E-01
0.956 1.4BE-01
n7RR MW-37 I ··--·-·--· .. ·--·· I ···-··--,···•··, I-· I I -·-I 1 ···--1 I 6.79E-06 ----~~-I Sulfate (mg/L) I 37 I I 2453_21 I 0.511 I 6.09E-10 I ALL 2023 SAR Data
ALL 2023 SAR Data
Notes:
a= sigma
%ND= percent of non-detected values
µg/L = micrograms per liter
0
I Uranium (µg/L) I 37 I 0 I 12.8 I
290.2
1.8 I 0.947 I 7.86E-02 I
N = number of valid data points
p = probability
W = Shapiro-Wilk test value
Normally or
Lognormally
distributed?
Normal
Not normal
Normal
Not normal
Not normal
Not normal
Normal
Normal
Not normal
Not normal
Normal
Least Squares
Regression Trend
Analysis"
Mann-Kendall Trend
Analyslsb
f p s . p IIEillilllB'llilEEillllllll!EIII
0.79 5.6E-17
NA NA
0.08 2.6E-01
NA NA
NA NA
NA NA
0.90 8.5E-09
0.04 2.2E-01
NA NA
NA NA
0.11 5.0E-02
S = Mann-Kendall statistic
FD = field duplicate
792 0.00
-2078 0.00
-34 0.09
8710 0.00
147 0.09
1856 0.00
105 0.00
-124 0.05
-97 0.10
-117 0.06
-119 0.06
Background
Report
Significant
Trend?
None
None
None
Upward
Upward
Upward
Upward
None
None
None
None
2023
Significant
Trend
Increasing
Decreasing
No Trend
Increasing
No Trend
Increasing
Increasing
No Trend
No Trend
No Trend
No Trend
mg/L = milligrams per liter r2 = The measure of how well lhe trendline fits the data where r2=1 represents a perfect fit.
a = A regression tesl was performed on data that was determined to have normal or log-normal distribution
b = The Mann-Kendall test was performed on data that are not normally or lognormally distributed
GWCL Subset Post 2019 = All data post July 1, 2019
Appendix B
Source Assesment Report for MW-11 and MW-37
White Mesa Uranium Mill
~INTERA Page 1 of 37 GE'OSCIENCE & ENGINEERING SOLUTIONS
Appendix B-2: Descriptive Statistics for Indicator Parameters in MW-11 and MW-37
Cata Set
Analyte
Units
% Non-Detects _
N
Normally or
Lognormally
Distributed?
Mean
Min. Cone.
Std.~v.
Range
Median
751n auartlle
Data Set
Analytc
Units
% Non-Detects
N
Normally or
Log normally
Distributed?
Mean
Mln,_Conc.
Max. Cone.
Std. Dev,
Range_
. Geometric Mean
Skewness
251h Quartile
Median
751}, Quartile
Appendix B
MW-11 2007 Background Report
Chloride Fluoride Sulfate _ ~aniu_!n
mg/L
0.0 0.0
14 71
Nol Normal Nol Normal Not Normal Not Normal
Lognormal or or or or
Lognormal Lognormal Lognormal
32,9 0.6 1014.3 0,9
24,4 0.5 659 0,0
43,2 0,7 1309 4.0
3.1 0.07 99.12 0,7
16,8 0.2 650 4.0
32.B 0,554 1009,6 0,431
0.5 0.97B 0.397 1.72
31.0 0.5 951 0.34
32,4 0,51 1000 0,75
0.6 I 1060 I 1.04 n
IM?ffiNH:ffl HH11,l·id¥t@
_Chl_o,r_idc . F.h_iorlde S_ulfate Uranium
WI I ·~:~ I ·~~t I ·~·~,
Nol Nomial Nonnal or Normal or or Lognormal Lognormal Loonormal
47.12 0.25 2543.33 13.16
36.00 0,22 2130,00 10,30
55.00 0,30 2750,00 18.10
5.20 0.03 192.16 2.46
19.00 0.0B 620,00 7.80
46.84 0.25 2536,52 12.97
-0.B4 0.52 -1.22 0.99
44.50 0.23 2460.00 11.40
47.70 0.25 2570.00 12.35
50,00 0.27 2700.00 15.50
Source Assesmenl Report for MW-11 and MW-37
Whfle Meu UrMlum Mill
Chlorlde
mg/!,.
Not Nonnal o
Lognormal
32.4
24.4
43.2
3.18
7B BO
32.22
0.56
30.B5
32,00
Chlo~lde
MW-11 2012 SAR MW-11 2019 SAR MW-11 2022 SAR MW-11 2023 SAR
Fluoride
mg{b_
Nol Normal
or
Lognom,al
0.5
0.4
0.7
0.06
0.27
0.54
1.36
0.50
0,54
Sultal~ _ _!.l_!_a~m Cl!!_orlde [!uo_ride Su Irate Uranium Chloride , Flu~ric!_e Sutfate UE'nium ChJoridc F~o!ide
0.7 0.0 0.0 22.00 0.6 0.0 0.0 21 0.5 0.0
B7 104 146 63 125 130 176 73 153 140 204 B5
Not Normal Nol Normal Nol Not Not Not Not Nol Not Nol Nol or or Normal Normal Normal Normal normal normal normal normal Not normal normal Lognormal Lognormal
90.B 0,6 32.37 0.50 1057.90 0,76 34.37 0.4B 1092.46 0.60 37.6 0.5
895 0,0 24.40 0,32 567,00 0.00 24.40 0.23 561,00 0,00 24.40 0,23
1309 3.0 42.40 0:71 1507,00 2.50 57.00 0.71 f507,00 2,50 B7.20 0.70
90.7B 0.59 2.92 0.07 122.57 0.45 5.77 0.09 141.61 0.47 11.54 0.11
414.00 3.03 16.00 0.39 946.00 2.50 32.60 0.47 946.00 2.50 62.BO 0.47
7035.17 0.48 32.24 0,50 1050.41 0.52 33.95 0.4B 1082.94 0,55 36.32 0.46
0.70 1.56 0,41 0.39 -0.24 1.17 1,65 -0.05 -0 06 1.09 2.03 -0.10
968.00 0.30 31.00 0,46 976.00 0,37 31.00 0.44 9B6.00 0,40 31.00 0.42
1023.00 0.75 32,00 0.49 7060.00 0.75 32.75 0.4B 1090,00 0,78 33.00 0.48 I 1090 I 1.0 I 34.00 I 0,54 1140.00 1.00 36.00 0.54 1170.00 1.00 38.45 o.51
MW-37 2023 SAR ~~Ji
F~uorid~ SJ!!fa~c Uranium
Sutfate
mg/L
Not normal
110].6
79,00
2250.00
1'114.55
2171.00
1085.56
0.31
1005.00
1110.00
1190.00
_ \.!T3!!iU~.
ug/L -..ea
Not
normaf
0.9
o.oo
4.00
0,67
4.00
0.61
1.71
0.41
0,81
1.04
_!!lg/_L,_ __ ,_ -~g~~ _ ~g/L __ , ugfl,. __ , ----11 --,
Normal Not normal Nol normal Normal
46.3 0.2B 2453 12.8
36.0 0,10 1010 10.3
55.0 1.00 2750 18.1
3.5 0.14 290 1.6
19.0 0 90 1740 7.B
46.1 0,26 242B 12.7
-0.1 4.15 -4 1,1
44.4 0.23 2360 11.6
46.3 0.26 2510 12.3
4B.7 0.30 2600 13.B
ISINTERA Page 2 of 37 GEOSCIENCE & ENGINEERING SOLUTIONS
Appendix B-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
Well I Sampl~ ,Parameter -R~sult -Units ;--Qualifier ---
MW-11 12/16/1982
MW-11 01/19/1983
MW-11 05/24/1983
MW-11 09/01/1983
MW-11 10/26/1983
MW-11 02/15/1984
MW-11 06/12/1984
MW-11 09/25/1984
MW-11 12/04/1984
MW-11 06/28/1985
MW-11 09/27/1985
MW-11 12/15/1985
MW-11 03/27/1986
MW-11 06/26/1986
MW-11 09/04/1986
MW-11 12/10/1986
MW-11 02/20/1987
MW-11 02/20/1987
MW-11 04/28/1987
MW-11 04/29/1987
MW-11 08/14/1987
MW-11 08/19/1987
MW-11 11/20/1987
MW-11 01/27/1988
MW-11 06/01/1988
MW-11 08/24/1988
MW-11 11/02/1988
MW-11 08/25/1989
MW-11 11/01/1989
MW-11 11/17/1989
MW-11 12/15/1989
MW-11 02/20/1990
MW-11 05/08/1990
MW-11 08/07/1990
MW-11 11/13/1990
MW-11 02/28/1991
MW-11 05/22/1991
MW-11 09/24/1991
MW-11 12/04/1991
MW-11 03/17/1992
MW-11 06/12/1992
MW-11 09/15/1992
MW-11 11/12/1992
MW-11 03/30/1993
MW-11 06/10/1993
MW-11 09/29/1993
MW-11 12/15/1993
MW-11 03/30/1994
Appendix B
Source Assesment Report for MW-11 and MW-37
White Mesa Uranium Mill
Chloride 24.4 mg/L
Chloride 32.0 mg/L
Chloride 26.8 mg/L
Chloride 32.0 mg/L
Chloride 26.0 mg/L
Chloride 31.0 mg/L
Chloride 32.0 mg/L
Chloride 34.0 mg/L
Chloride 32.0 mg/L
Chloride 31.0 mg/L
Chloride 38.0 mg/L
Chloride 71.0 mg/L
Chloride 35.0 mg/L
Chloride 70.0 mg/L
Chloride 32.0 mg/L
Chloride 33.0 mg/L
Chloride 32.0 mg/L
Chloride 32.0 mg/L
Chloride 43.2 mg/L
Chloride 43.2 mg/L
Chloride 33.0 mg/L
Chloride 33.0 mg/L
Chloride 31.9 mg/L
Chloride 31.0 mg/L
Chloride 32.0 mg/L
Chloride 33.5 mg/L
Chloride 35.2 mg/L
Chloride 34.0 mg/L
Chloride 32.0 mg/L
Chloride 34.0 mg/L
Chloride 35.0 mg/L
Chloride 33.0 mg/L
Chloride 33.0 mg/L
Chloride 33.0 mg/L
Chloride 34.0 mg/L
Chloride 31.0 mg/L
Chloride 30.0 mg/L
Chloride 30.0 mg/L
Chloride 31.0 mg/L
Chloride 32.0 mg/L
Chloride 29.0 mg/L
Chloride 31.0 mg/L
Chloride 41.0 mg/L
Chloride 35.0 mg/L
Chloride 39.0 mg/L
Chloride 36 .0 mg/L
Chloride 33.0 mg/L
Chloride 32.0 mg/L
Page 3 of 37 B INTERA
Appendix B-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
Well _: Sample Date I Parameter ~ __ Result
MW-11 03/30/1994
MW-11 06/20/1994
MW-11 08/23/1994
MW-11 12/07/1994
MW-11 03/14/1995
MW-11 06/27/1995
MW-11 09/15/1995
MW-11 03/27/1996
MW-11 06/06/1996
MW-11 09/12/1996
MW-11 09/17/1996
MW-11 11/22/1996
MW-11 03/19/1997
MW-11 06/11/1997
MW-11 09/30/1997
MW-11 01/08/1998
MW-11 03/16/1998
MW-11 05/12/1998
MW-11 09/24/1998
MW-11 11/03/1998
MW-11 02/18/1999
MW-11 05/11/1999
MW-11 09/30/1999
MW-11 12/09/1999
MW-11 03/17/2000
MW-11 06/06/2000
MW-11 09/03/2000
MW-11 11/27/2000
MW-11 03/23/2001
MW-11 06/12/2001
MW-11 09/04/2001
MW-11 11/06/2001
MW-11 03/14/2002
MW-11 05/20/2002
MW-11 09/10/2002
MW-11 09/10/2002
MW-11 11/21/2002
MW-11 03/20/2003
MW-11 06/27/2003
MW-11 09/24/2003
MW-11 11/24/2003
MW-11 03/19/2004
MW-11 05/27/2004
MW-11 09/14/2004
MW-11 11/09/2004
MW-11 03/30/2005
MW-11 03/30/2005
MW-11 06/21/2005
Appendix B
Source Assesment Report for MW-11 and MW-37
White Mesa Uranium Mill
Chloride 28.0
Chloride 32.0
Chloride 32.0
Chloride 32.0
Chloride 31.0
Chloride 37.0
Chloride 32.0
Chloride 35.6
Chloride 35.3
Chloride 32.8
Chloride 31.0
Chloride 31.6
Chloride 28.7
Chloride 29.2
Chloride 31.2
Chloride 32.4
Chloride 30.0
Chloride 33.7
Chloride 32.4
Chloride 31.4
Chloride 31.8
Chloride 33.1
Chloride 35.0
Chloride 29.1
Chloride 28.4
Chloride 35.4
Chloride 37.5
Chloride 37.3
Chloride 31.1
Chloride 36.5
Chloride 32.0
Chloride 42.4
Chloride 30.7
Chloride 35.9
Chloride 37.1
Chloride 33 .8
Chloride 37.7
Chloride 36.6
Chloride 29.3
Chloride 36.6
Chloride 35.5
Chloride 35.6
Chloride 36.0
Chloride 34.2
Chloride 29.5
Chloride 33 .0
Chloride 31.0
Chloride 31.0
Page 4 of 37
, _Units~-~~ Qualifier _I
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L u
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
BINTERA
Appendix B-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
Well_l -Sample Oat~ Parameter --~Result --
MW-11 06/21/2005
MW-11 09/22/2005
MW-11 09/22/2005
MW-11 12/13/2005
MW-11 12/13/2005
MW-11 03/21/2006
MW-11 06/20/2006
MW-11 06/20/2006
MW-11 09/13/2006
MW-11 10/25/2006
MW-11 03/15/2007
MW-11 08/21/2007
MW-11 10/30/2007
MW-11 03/18/2008
MW-11 06/16/2008
MW-11 08/05/2008
MW-11 11/10/2008
MW-11 02/16/2009
MW-11 05/17/2009
MW-11 08/31/2009
MW-11 10/19/2009
MW-11 02/10/2010
MW-11 04/28/2010
MW-11 09/08/2010
MW-11 11 /11/2010
MW-11 02/02/2011
MW-11 04/04/2011
MW-11 08/03/2011
MW-11 10/04/2011
MW-11 02/13/2012
MW-11 05/08/2012
MW-11 07/11/2012
MW-11 11/12/2012
MW-11 02/20/2013
MW-11 05/14/2013
MW-11 07/10/2013
MW-11 11/19/2013
MW-11 02/24/2014
MW-11 03/11/2014
MW-11 06/03/2014
MW-11 09/08/2014
MW-11 11/17/2014
MW-11 02/03/2015
MW-11 04/08/2015
MW-11 08/10/2015
MW-11 11/11/2015
MW-11 02/08/2016
MW-11 05/03/2016
Appendix B
Source Assesment Report for MW-11 and MW-37
White Mesa Uranium Mill
Chloride 30.0
Chloride 33.0
Chloride 33.0
Chloride 36.0
Chloride 31.0
Chloride 33.0
Chloride 31.0
Chloride 31.0
Chloride 29.0
Chloride 32.0
Chloride 31.0
Chloride 30.0
Chloride 29.0
Chloride 29.0
Chloride 30.0
Chloride 29.0
Chloride 30.0
Chloride 29.0
Chloride 26.0
Chloride 26.0
Chloride 30.0
Chloride 33.0
Chloride 32.0
Chloride 31.0
Chloride 34.0
Chloride 32.0
Chloride 31.0
Chloride 31.0
Chloride 28.0
Chloride 31.0
Chloride 30.0
Chloride 39.0
Chloride 30.0
Chloride 33.7
Chloride 30.1
Chloride 29.0
Chloride 31.3
Chloride 30.8
Chloride 32.6
Chloride 32.9
Chloride 31.0
Chloride 27.4
Chloride 31.0
Chloride 32.5
Chloride 37.3
Chloride 30.6
Chloride 34.0
Chloride 30.7
Page 5 of 37
Units Qualifier -- --••-----
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
B INTERA
Appendix 8-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
~I-----= Sample ~a_te ~ -Parameter '. Result ---Units - ' Qualifier ~
MW-11 08/16/2016 Chloride 33.9 mg/L
MW-11 11/07/2016 Chloride 35.1 mg/L
MW-11 02/08/2017 Chloride 31.5 mg/L
MW-11 05/02/2017 Chloride 33.3 mg/L
MW-11 08/15/2017 Chloride 32.7 mg/L
MW-11 11/07/2017 Chloride 31.9 mg/L
MW-11 02/20/2018 Chloride 31.9 mg/L
MW-11 04/18/2018 Chloride 34.0 mg/L
MW-11 09/11/2018 Chloride 36.4 mg/L
MW-11 10/25/2018 Chloride 29.3 mg/L
MW-11 01/15/2019 Chloride 32.0 mg/L
MW-11 04/24/2019 Chloride 34.0 mg/L
MW-11 07/16/2019 Chloride 48.4 mg/L
MW-11 10/15/2019 Chloride 30.8 mg/L
MW-11 11/12/2019 Chloride 39.1 mg/L
MW-11 12/03/2019 Chloride 35.4 mg/L
MW-11 01/15/2020 Chloride 38.9 mg/L
MW-11 02/04/2020 Chloride 42.1 mg/L
MW-11 03/10/2020 Chloride 41.0 mg/L
MW-11 04/08/2020 Chloride 38.3 mg/L
MW-11 05/05/2020 Chloride 39.0 mg/L
MW-11 06/02/2020 Chloride 40.1 mg/L
MW-11 07/07/2020 Chloride 42.1 mg/L
MW-11 08/11/2020 Chloride 43.9 mg/L
MW-11 09/02/2020 Chloride 40.6 mg/L
MW-11 10/12/2020 Chloride 44.8 mg/L
MW-11 11/16/2020 Chloride 33.7 mg/L
MW-11 12/07/2020 Chloride 37.4 mg/L
MW-11 01/12/2021 Chloride 46.4 mg/L
MW-11 02/09/2021 Chloride 46.4 mg/L
MW-11 03/08/2021 Chloride 46.9 mg/L
MW-11 04/20/2021 Chloride 47.7 mg/L
MW-11 05/10/2021 Chloride 46.4 mg/L
MW-11 06/08/2021 Chloride 52.1 mg/L
MW-11 07/27/2021 Chloride 48.3 mg/L
MW-11 08/10/2021 Chloride 57.0 mg/L
MW-11 09/07/2021 Chloride 49.6 mg/L
MW-11 10/20/2021 Chloride 52.8 mg/L
MW-11 11/16/2021 Chloride 53.6 mg/L
MW-11 12/13/2021 Chloride 53.9 mg/L
MW-11 01/18/2022 Chloride 51.1 mg/L
MW-11 02/08/2022 Chloride 57.2 mg/L
MW-11 03/08/2022 Chloride 67.7 mg/L
MW-11 04/18/2022 Chloride 54.9 mg/L
MW-11 05/04/2022 Chloride 59.5 mg/L
MW-11 06/06/2022 Chloride 46.4 mg/L
MW-11 07/12/2022 Chloride 54.0 mg/L
MW-11 08/08/2022 Chloride 67.4 mg/L
Appendix B
Source Assesment Report for MW-11 and MW-37 B INTERA White Mesa Uranium Mill Page 6 of 37
Appendix B-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
. I Well Sample Date Parameter ' . -----------------MW-11 09/21/2022
MW-11 10/10/2022
MW-11 11/08/2022
MW-11 12/14/2022
MW-11 01/25/2023
MW-11 02/08/2023
MW-11 03/14/2023
MW-11 04/17/2023
MW-11 05/09/2023
MW-11 06/05/2023
MW-11 07/11/2023
MW-11 08/02/2023
MW-11 05/24/1983
MW-11 05/11/1999
MW-11 11/27/2000
MW-11 11/06/2001
MW-11 09/10/2002
MW-11 04/01/2005
MW-11 06/23/2005
MW-11 09/27/2005
MW-11 12/15/2005
MW-11 03/23/2006
MW-11 06/23/2006
MW-11 09/14/2006
MW-11 10/27/2006
MW-11 03/20/2007
MW-11 08/24/2007
MW-11 11/02/2007
MW-11 03/21/2008
MW-11 06/20/2008
MW-11 08/08/2008
MW-11 11/14/2008
MW-11 02/18/2009
MW-11 05/19/2009
MW-11 09/01/2009
MW-11 10/22/2009
MW-11 02/10/2010
MW-11 02/16/2010
MW-11 04/28/2010
MW-11 09/08/2010
MW-11 11 /11/2010
MW-11 02/02/2011
MW-11 04/04/2011
MW-11 08/03/2011
MW-11 10/04/2011
MW-11 02/13/2012
MW-11 05/08/2012
MW-11 07/11/2012
Appendix B
Source Assesment Report for MW-11 and MW-37
White Mesa Uranium Mill
Chloride
Chloride
Chloride
Chloride
Chloride
Chloride
Chloride
Chloride
Chloride
Chloride
Chloride
Chloride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Fluoride
Page 7 of 37
Result Units Qualifier --------------
68.1 mg/L
72.1 mg/L
71.9 mg/L
52.3 mg/L
70.7 mg/L
71.4 mg/L
66.3 mg/L
70.6 mg/L
66.0 mg/L
69.0 mg/L
77.1 mg/L
87.2 mg/L
0.5 mg/L
0.51 mg/L
0.5 mg/L
0.5 mg/L
0.5 mg/L
0.49 mg/L
0.7 mg/L
0.58 mg/L
0.54 mg/L
0.56 mg/L
0.52 mg/L
0.60 mg/L
0.71 mg/L
0.56 mg/L
0.67 mg/L
0.54 mg/L
0.57 mg/L
0.53 mg/L
0.54 mg/L
0.56 mg/L
0.56 mg/L
0.55 mg/L
0.55 mg/L
0.54 mg/L
0.51 mg/L
0.51 mg/L
0.49 mg/L
0.52 mg/L
0.49 mg/L
0.48 mg/L
0.44 mg/L
0.48 mg/L
0.56 mg/L
0.57 mg/L
0.49 mg/L
0.48 mg/L
~INTERA
Appendix 8-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
Well Sample Date --Parameter I Result Units , Qualifier -_____ J---~---------~-------~---
MW-11 11/12/2012
MW-11 02/20/2013
MW-11 05/14/2013
MW-11 07/10/2013
MW-11 11/19/2013
MW-11 02/24/2014
MW-11 03/11/2014
MW-11 06/03/2014
MW-11 09/08/2014
MW-11 11/17/2014
MW-11 02/03/2015
MW-11 04/08/2015
MW-11 08/10/2015
MW-11 11/11/2015
MW-11 02/08/2016
MW-11 05/03/2016
MW-11 08/16/2016
MW-11 11/07/2016
MW-11 02/08/2017
MW-11 05/02/2017
MW-11 08/15/2017
MW-11 11/07/2017
MW-11 02/20/2018
MW-11 04/18/2018
MW-11 09/11/2018
MW-11 10/25/2018
MW-11 01/15/2019
MW-11 04/24/2019
MW-11 07/16/2019
MW-11 07/16/2019
MW-11 10/15/2019
MW-11 01/15/2020
MW-11 04/08/2020
MW-11 10/12/2020
MW-11 01/12/2021
MW-11 04/20/2021
MW-11 07/27/2021
MW-11 10/20/2021
MW-11 01/18/2022
MW-11 04/18/2022
MW-11 07/12/2022
MW-11 10/10/2022
MW-11 01/25/2023
MW-11 04/17/2023
MW-11 07/11/2023
MW-11 12/16/1982
MW-11 05/24/1983
MW-11 10/26/1983
Appendix B
Source Assesment Report for MW-11 and MW-37
White Mesa Uranium Mill
Fluoride 0.47 mg/L
Fluoride 0.48 mg/L
Fluoride 0.48 mg/L
Fluoride 0.64 mg/L
Fluoride 0.48 mg/L
Fluoride 0.48 mg/L
Fluoride 0.54 mg/L
Fluoride 0.49 mg/L
Fluoride 0.50 mg/L
Fluoride 0.42 mg/L
Fluoride 0.46 mg/L
Fluoride 0.32 mg/L
Fluoride 0.33 mg/L
Fluoride 0.47 mg/L
Fluoride 0.44 mg/L
Fluoride 0.45 mg/L
Fluoride 0.47 mg/L
Fluoride 0.45 mg/L
Fluoride 0.42 mg/L
Fluoride 0.44 mg/L
Fluoride 0.43 mg/L
Fluoride 0.47 mg/L
Fluoride 0.44 mg/L
Fluoride 0.47 mg/L
Fluoride 0.36 mg/L
Fluoride 0.42 mg/L
Fluoride 0.41 mg/L
Fluoride 0.43 mg/L
Fluoride 0.32 mg/L
Fluoride 0.32 mg/L
Fluoride 0.23 mg/L
Fluoride 0.36 mg/L
Fluoride 0.38 mg/L
Fluoride 0.63 mg/L
Fluoride 0.41 mg/L
Fluoride 0.39 mg/L
Fluoride 0.35 mg/L
Fluoride 0.38 mg/L
Fluoride 0.37 mg/L
Fluoride 0.30 mg/L
Fluoride 0.25 mg/L
Fluoride 0.23 mg/L
Fluoride 0.36 mg/L
Fluoride 0.28 mg/L
Fluoride 0.27 mg/L
Sulfate 926 mg/L
Sulfate 943 mg/L
Sulfate 922 mg/L
Page 8 of 37 B INTERA
Appendix B-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
, ___ ~_!I!_ _ j _ _ ~mple Da!e _ -Pa-rameter , Result , Units : Qualifier _ -~
MW-11 02/15/1984 Sulfate 2250 mg/L
MW-11 06/12/1984 Sulfate 920 mg/L
MW-11 12/04/1984 Sulfate 949 mg/L
MW-11 06/28/1985 Sulfate 909 mg/L
MW-11 09/27/1985 Sulfate 1025 mg/L
MW-11 12/15/1985 Sulfate 79 mg/L
MW-11 03/27/1986 Sulfate 946 mg/L
MW-11 06/26/1986 Sulfate 949 mg/L
MW-11 09/04/1986 Sulfate 956 mg/L
MW-11 12/10/1986 Sulfate 911 mg/L
MW-11 02/20/1987 Sulfate 895 mg/L
MW-11 02/20/1987 Sulfate 977 mg/L
MW-11 04/28/1987 Sulfate 1020 mg/L
MW-11 04/29/1987 Sulfate 1020 mg/L
MW-11 08/14/1987 Sulfate 951 mg/L
MW-11 08/19/1987 Sulfate 951 mg/L
MW-11 11/20/1987 Sulfate 961 mg/L
MW-11 01/27/1988 Sulfate 919 mg/L
MW-11 06/01/1988 Sulfate 947 mg/L
MW-11 08/24/1988 Sulfate 915 mg/L
MW-11 11/02/1988 Sulfate 974 mg/L
MW-11 08/25/1989 Sulfate 1030 mg/L
MW-11 11/01/1989 Sulfate 986 mg/L
MW-11 11/17/1989 Sulfate 993 mg/L
MW-11 12/15/1989 Sulfate 1010 mg/L
MW-11 02/20/1990 Sulfate 1010 mg/L
MW-11 05/08/1990 Sulfate 1000 mg/L
MW-11 08/07/1990 Sulfate 973 mg/L
MW-11 11/13/1990 Sulfate 975 mg/L
MW-11 02/28/1991 Sulfate 967 mg/L
MW-11 05/22/1991 Sulfate 936 mg/L
MW-11 09/24/1991 Sulfate 956 mg/L
MW-11 12/04/1991 Sulfate 968 mg/L
MW-11 03/17/1992 Sulfate 976 mg/L
MW-11 06/12/1992 Sulfate 976 mg/L
MW-11 09/15/1992 Sulfate 1005 mg/L
MW-11 11/12/1992 Sulfate 1507 mg/L
MW-11 03/30/1993 Sulfate 1162 mg/L
MW-11 06/10/1993 Sulfate 1309 mg/L
MW-11 09/29/1993 Sulfate 1307 mg/L
MW-11 12/15/1993 Sulfate 1054 mg/L
MW-11 03/30/1994 Sulfate 1020 mg/L
MW-11 03/30/1994 Sulfate 1050 mg/L
MW-11 06/20/1994 Sulfate 1118 mg/L
MW-11 08/23/1994 Sulfate 1035 mg/L
MW-11 12/07/1994 Sulfate 983 mg/L
MW-11 03/14/1995 Sulfate 1010 mg/L
MW-11 06/27/1995 Sulfate 659 mg/L
Appendix B
Source Assesment Report for MW-11 and MW-37 ira-2:-,NTERA White Mesa Uranium Mill Page 9 of 37
Appendix 8-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
__ Well _j Sample Date : Parameter~--Result ._ i..!!1_i!!_~~-_
MW-11 09/15/1995 Sulfate 978 mg/L
MW-11 03/27/1996 Sulfate 1008 mg/L
MW-11 06/06/1996 Sulfate 1051 mg/L
MW-11 09/12/1996 Sulfate 1061 mg/L
MW-11 09/17/1996 Sulfate 1085 mg/L
MW-11 11/22/1996 Sulfate 981 mg/L
MW-11 03/19/1997 Sulfate 922 mg/L
MW-11 05/11/1999 Sulfate 945 mg/L
MW-11 11/27/2000 Sulfate 1140 mg/L
MW-11 11/06/2001 Sulfate 1150 mg/L
MW-11 09/10/2002 Sulfate 1160 mg/L
MW-11 09/10/2002 Sulfate 1220 mg/L
MW-11 03/30/2005 Sulfate 1080 mg/L D
MW-11 03/30/2005 Sulfate 1180 mg/L D
MW-11 06/21/2005 Sulfate 1090 mg/L
MW-11 06/21/2005 Sulfate 1070 mg/L
MW-11 09/22/2005 Sulfate 968 mg/L
MW-11 09/22/2005 Sulfate 973 mg/L
MW-11 12/13/2005 Sulfate 1070 mg/L D
MW-11 12/13/2005 Sulfate 1060 mg/L D
MW-11 03/21/2006 Sulfate 1120 mg/L D
MW-11 06/20/2006 Sulfate 1150 mg/L D
MW-11 06/20/2006 Sulfate 1150 mg/L D
MW-11 09/13/2006 Sulfate 1060 mg/L D
MW-11 10/25/2006 Sulfate 1200 mg/L D
MW-11 03/15/2007 Sulfate 1120 mg/L D
MW-11 08/21/2007 Sulfate 1060 mg/L D
MW-11 10/30/2007 Sulfate 1020 mg/L D
MW-11 03/18/2008 Sulfate 1040 mg/L D
MW-11 06/16/2008 Sulfate 1050 mg/L D
MW-11 08/05/2008 Sulfate 1060 mg/L D
MW-11 11/10/2008 Sulfate 1100 mg/L D
MW-11 02/16/2009 Sulfate 977 mg/L D
MW-11 05/17/2009 Sulfate 1060 mg/L D
MW-11 08/31/2009 Sulfate 1090 mg/L D
MW-11 10/19/2009 Sulfate 1040 mg/L D
MW-11 02/10/2010 Sulfate 1140 mg/L D
MW-11 04/28/2010 Sulfate 1150 mg/L D
MW-11 09/08/2010 Sulfate 1140 mg/L D
MW-11 11/11/2010 Sulfate 1180 mg/L D
MW-11 02/02/2011 Sulfate 1190 mg/L D
MW-11 04/04/2011 Sulfate 1140 mg/L D
MW-11 08/03/2011 Sulfate 1090 mg/L D
MW-11 10/04/2011 Sulfate 1140 mg/L D
MW-11 02/13/2012 Sulfate 1160 mg/L D
MW-11 05/08/2012 Sulfate 1090 mg/L D
MW-11 07/11/2012 Sulfate 1080 mg/L D
MW-11 11/12/2012 Sulfate 1110 mg/L
Appendix B
Source Assesment Report for MW-11 and MW-37 ~INTERA White Mesa Uranium Mill Page 10 of 37
Appendix 8-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
___ Well~-_ '. _ Sample Date • Parameter I Result ~ • Units . _ Qualifier '
MW-11 02/20/2013 Sulfate 1080 mg/L
MW-11 05/14/2013 Sulfate 763 mg/L
MW-11 07/10/2013 Sulfate 1240 mg/L
MW-11 11/19/2013 Sulfate 1050 mg/L
MW-11 02/24/2014 Sulfate 1150 mg/L
MW-11 03/11/2014 Sulfate 904 mg/L
MW-11 06/03/2014 Sulfate 1140 mg/L
MW-11 09/08/2014 Sulfate 1030 mg/L
MW-11 11/17/2014 Sulfate 1140 mg/L
MW-11 02/03/2015 Sulfate 1110 mg/L
MW-11 04/08/2015 Sulfate 1170 mg/L
MW-11 08/10/2015 Sulfate 1050 mg/L
MW-11 11/11/2015 Sulfate 1220 mg/L
MW-11 02/08/2016 Sulfate 1160 mg/L
MW-11 05/03/2016 Sulfate 1200 mg/L
MW-11 08/16/2016 Sulfate 1160 mg/L
MW-11 11/07/2016 Sulfate 1290 mg/L
MW-11 02/08/2017 Sulfate 1050 mg/L
MW-11 05/02/2017 Sulfate 1140 mg/L
MW-11 08/15/2017 Sulfate 1360 mg/L
MW-11 11/07/2017 Sulfate 1060 mg/L
MW-11 12/05/2017 Sulfate 1130 mg/L
MW-11 01/24/2018 Sulfate 561 mg/L
MW-11 02/20/2018 Sulfate 1120 mg/L
MW-11 03/06/2018 Sulfate 1180 mg/L
MW-11 04/18/2018 Sulfate 1110 mg/L
MW-11 05/15/2018 Sulfate 1140 mg/L
MW-11 06/19/2018 Sulfate 1060 mg/L
MW-11 07/24/2018 Sulfate 1170 mg/L
MW-11 08/09/2018 Sulfate 1090 mg/L
MW-11 09/11/2018 Sulfate 1160 mg/L
MW-11 10/25/2018 Sulfate 1190 mg/L
MW-11 01/15/2019 Sulfate 1150 mg/L
MW-11 04/24/2019 Sulfate 1160 mg/L
MW-11 07/16/2019 Sulfate 1410 mg/L
MW-11 10/15/2019 Sulfate 1290 mg/L
MW-11 11/12/2019 Sulfate 1140 mg/L
MW-11 12/03/2019 Sulfate 1100 mg/L
MW-11 01/15/2020 Sulfate 1180 mg/L
MW-11 02/04/2020 Sulfate 1260 mg/L
MW-11 03/10/2020 Sulfate 1120 mg/L
MW-11 04/08/2020 Sulfate 1180 mg/L
MW-11 05/05/2020 Sulfate 1180 mg/L
MW-11 06/02/2020 Sulfate 1310 mg/L
MW-11 07/07/2020 Sulfate 1260 mg/L
MW-11 08/11/2020 Sulfate 1220 mg/L
MW-11 09/02/2020 Sulfate 1170 mg/L
MW-11 10/12/2020 Sulfate 1300 mg/L
Appendix B
Source Assesment Report for MW-11 and MW-37 B INTERA White Mesa Uranium Mill Page 11 of 37
Appendix B-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
; Well _i ~ Sample Date ~ Parameter I Result I Units ; -Qualifier
~
MW-11 11/16/2020
MW-11 12/07/2020
MW-11 01/12/2021
MW-11 02/09/2021
MW-11 03/08/2021
MW-11 04/20/2021
MW-11 05/10/2021
MW-11 06/08/2021
MW-11 07/27/2021
MW-11 08/10/2021
MW-11 09/07/2021
MW-11 10/20/2021
MW-11 11/16/2021
MW-11 12/13/2021
MW-11 01/18/2022
MW-11 02/08/2022
MW-11 03/08/2022
MW-11 04/18/2022
MW-11 05/04/2022
MW-11 06/06/2022
MW-11 07/12/2022
MW-11 08/08/2022
MW-11 09/21/2022
MW-11 10/10/2022
MW-11 11/08/2022
MW-11 12/14/2022
MW-11 01/25/2023
MW-11 02/08/2023
MW-11 03/14/2023
MW-11 04/17/2023
MW-11 05/09/2023
MW-11 06/05/2023
MW-11 07/11/2023
MW-11 08/02/2023
MW-11 05/24/1983
MW-11 12/15/1985
MW-11 12/10/1986
MW-11 02/20/1987
MW-11 04/29/1987
MW-11 08/19/1987
MW-11 01/27/1988
MW-11 06/01/1988
MW-11 08/24/1988
MW-11 11/02/1988
MW-11 03/09/1989
MW-11 06/22/1989
MW-11 08/25/1989
MW-11 10/31/1989
Appendix B
Source Assesment Report for MW-11 and MW-37
White Mesa Uranium Mill
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Sulfate
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Page 12 of 37
858 mg/L
1330 mg/L
1140 mg/L
1260 mg/L
1270 mg/L
1290 mg/L
1280 mg/L
1270 mg/L
1470 mg/L
1370 mg/L
1240 mg/L
1360 mg/L
1300 mg/L
1350 mg/L
1020 mg/L
1240 mg/L
1170 mg/L
1240 mg/L
1270 mg/L
866 mg/L
1390 mg/L
1260 mg/L
1300 mg/L
1140 mg/L
1140 mg/L
1330 mg/L
1240 mg/L
1100 mg/L
1430 mg/L
1330 mg/L
1230 mg/L
1340 mg/L
1370 mg/L
1190 mg/L
1.00 ug/L u
0.75 ug/L
0.30 ug/L u
0.30 ug/L u
0.30 ug/L
1.04 ug/L
0.30 ug/L u
0.75 ug/L
0.75 ug/L
0.40 ug/L
1.34 ug/L
1.19 ug/L
2.39 ug/L
1.04 ug/L
B INTERA
Appendix B-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
---
_ j _ -Sample Date I Parameter ~I Result !_ _ Uni~ Qualifier ] Well
MW-11 11/17/1989
MW-11 11/29/1989
MW-11 12/15/1989
MW-11 01/24/1990
MW-11 02/20/1990
MW-11 05/08/1990
MW-11 08/07/1990
MW-11 11/13/1990
MW-11 02/28/1991
MW-11 05/22/1991
MW-11 09/24/1991
MW-11 12/04/1991
MW-11 06/12/1992
MW-11 03/30/1993
MW-11 06/10/1993
MW-11 09/29/1993
MW-11 12/15/1993
MW-11 06/20/1994
MW-11 08/23/1994
MW-11 08/23/1994
MW-11 12/07/1994
MW-11 12/07/1994
MW-11 03/14/1995
MW-11 06/27/1995
MW-11 06/27/1995
MW-11 09/15/1995
MW-11 09/15/1995
MW-11 12/07/1995
MW-11 03/27/1996
MW-11 06/06/1996
MW-11 09/12/1996
MW-11 11/22/1996
MW-11 03/19/1997
MW-11 06/11/1997
MW-11 09/30/1997
MW-11 01/08/1998
MW-11 03/16/1998
MW-11 05/12/1998
MW-11 09/24/1998
MW-11 11/03/1998
MW-11 02/18/1999
MW-11 05/11/1999
MW-11 09/30/1999
MW-11 12/09/1999
MW-11 03/17/2000
MW-11 06/06/2000
MW-11 09/03/2000
MW-11 11/27/2000
Appendix B
Source Assesment Report for MW-11 and MW-37
White Mesa Uranium Mill
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Uranium
Page 13 of 37
0.90 ug/L
0.90 ug/L
0.75 ug/L
1.04 ug/L
1.04 ug/L
1.19 ug/L
0.70 ug/L
0.90 ug/L
0.30 ug/L u
0.34 ug/L
1.10 ug/L
0.36 ug/L
0.30 ug/L u
3.03 ug/L
4.00 ug/L
2.01 ug/L
0.30 ug/L u
1.21 ug/L
1.01 ug/L
1.52 ug/L
1.00 ug/L
0.30 ug/L u
0.30 ug/L u
0.80 ug/L
0.30 ug/L u
1.40 ug/L
0.30 ug/L u
0.30 ug/L u
0.40 ug/L
0.50 ug/L
1.10 ug/L
1.80 ug/L
0.30 ug/L u
1.00 ug/L
0.40 ug/L
0.00 ug/L u
0.00 ug/L
0.00 ug/L
0.00 ug/L
0.00 ug/L u
0.40 ug/L
0.70 ug/L
0.50 ug/L
0.40 ug/L
0.30 ug/L
0.30 ug/L u
0.60 ug/L
2.20 ug/L
~INTERA
Appendix B-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
Well Sample Date 1 -Parameter I Result : Units Qualifier --------~ ~--~~---_J ---------
MW-11 03/23/2001 Uranium 2.90 ug/L
MW-11 06/12/2001 Uranium 2.50 ug/L
MW-11 09/04/2001 Uranium 1.30 ug/L
MW-11 11/06/2001 Uranium 1.50 ug/L
MW-11 05/20/2002 Uranium 1.00 ug/L
MW-11 11/21/2002 Uranium 1.00 ug/L
MW-11 03/20/2003 Uranium 0.80 ug/L
MW-11 06/27/2003 Uranium 1.60 ug/L
MW-11 09/24/2003 Uranium 1.00 ug/L
MW-11 11/24/2003 Uranium 0.30 ug/L u
MW-11 03/19/2004 Uranium 1.00 ug/L
MW-11 05/27/2004 Uranium 1.00 ug/L u
MW-11 09/14/2004 Uranium 1.00 ug/L u
MW-11 11/09/2004 Uranium 1.00 ug/L u
MW-11 06/21/2005 Uranium 0.76 ug/L
MW-11 09/22/2005 Uranium 0.63 ug/L
MW-11 12/13/2005 Uranium 0.83 ug/L
MW-11 03/21/2006 Uranium 0.81 ug/L
MW-11 06/20/2006 Uranium 1.02 ug/L
MW-11 09/13/2006 Uranium 0.62 ug/L
MW-11 10/25/2006 Uranium 1.04 ug/L
MW-11 03/15/2007 Uranium 1.04 ug/L
MW-11 08/21/2007 Uranium 0.30 ug/L u
MW-11 10/30/2007 Uranium 0.30 ug/L u
MW-11 03/18/2008 Uranium 0.30 ug/L u
MW-11 06/16/2008 Uranium 0.30 ug/L u
MW-11 08/05/2008 Uranium 0.30 ug/L u
MW-11 11/10/2008 Uranium 0.30 ug/L u
MW-11 02/16/2009 Uranium 0.30 ug/L u
MW-11 05/17/2009 Uranium 0.30 ug/L u
MW-11 08/31/2009 Uranium 0.33 ug/L
MW-11 10/19/2009 Uranium 0.31 ug/L
MW-11 02/10/2010 Uranium 0.92 ug/L
MW-11 04/28/2010 Uranium 0.96 ug/L
MW-11 09/08/2010 Uranium 1.06 ug/L
MW-11 11/11/2010 Uranium 0.87 ug/L
MW-11 02/02/2011 Uranium 0.42 ug/L
MW-11 04/04/2011 Uranium 0.96 ug/L
MW-11 08/03/2011 Uranium 0.48 ug/L
MW-11 10/04/2011 Uranium 0.47 ug/L
MW-11 02/13/2012 Uranium 0.85 ug/L
MW-11 05/08/2012 Uranium 0.62 ug/L
MW-11 07/11/2012 Uranium 0.73 ug/L
MW-11 11/12/2012 Uranium 0.79 ug/L
MW-11 02/20/2013 Uranium 0.59 ug/L
MW-11 05/14/2013 Uranium 0.69 ug/L
MW-11 07/10/2013 Uranium 0.67 ug/L
MW-11 11/19/2013 Uranium 0.90 ug/L
Appendix B
Source Assesment Report for MW-11 and MW-37 ~~INTERA White Mesa Uranium Mill Page 14 of 37
Appendix 8-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
l=------W~_!I ] --~c!mp_l_e ~ate~ ~ _P_ai:_ameter j Result _] Units ;_ Qualifie_r, ;
MW-11 02/24/2014 Uranium 1.00 ug/L
MW-11 03/11/2014 Uranium 0.67 ug/L
MW-11 06/03/2014 Uranium 0.94 ug/L
MW-11 09/08/2014 Uranium 0.50 ug/L u
MW-11 11/17/2014 Uranium 0.54 ug/L
MW-11 02/03/2015 Uranium 0.56 ug/L
MW-11 04/08/2015 Uranium 0.90 ug/L
MW-11 08/10/2015 Uranium 0.77 ug/L
MW-11 11/11/2015 Uranium 0.58 ug/L
MW-11 02/08/2016 Uranium 1.16 ug/L
MW-11 05/03/2016 Uranium 0.78 ug/L
MW-11 08/16/2016 Uranium 0.77 ug/L
MW-11 11/07/2016 Uranium 1.08 ug/L
MW-11 02/08/2017 Uranium 0.79 ug/L
MW-11 05/02/2017 Uranium 0.81 ug/L
MW-11 08/15/2017 Uranium 0.95 ug/L
MW-11 11/07/2017 Uranium 0.73 ug/L
MW-11 02/20/2018 Uranium 0.53 ug/L
MW-11 04/18/2018 Uranium 0.85 ug/L
MW-11 09/11/2018 Uranium 0.76 ug/L
MW-11 10/25/2018 Uranium 0.73 ug/L
MW-11 01/15/2019 Uranium 0.86 ug/L
MW-11 04/24/2019 Uranium 0.94 ug/L
MW-11 07/16/2019 Uranium 1.08 ug/L
MW-11 10/15/2019 Uranium 1.01 ug/L
MW-11 01/15/2020 Uranium 0.82 ug/L
MW-11 04/08/2020 Uranium 1.01 ug/L
MW-11 07/07/2020 Uranium 0.95 ug/L
MW-11 10/12/2020 Uranium 1.33 ug/L
MW-11 01/12/2021 Uranium 1.33 ug/L
MW-11 04/20/2021 Uranium 1.49 ug/L
MW-11 07/27/2021 Uranium 2.21 ug/L
MW-11 10/20/2021 Uranium 2.08 ug/L
MW-11 01/18/2022 Uranium 1.78 ug/L
MW-11 04/18/2022 Uranium 1.90 ug/L
MW-11 07/12/2022 Uranium 2.60 ug/L
MW-11 10/10/2022 Uranium 2.40 ug/L
MW-11 01/25/2023 Uranium 2.60 ug/L
MW-11 04/17/2023 Uranium 2.60 ug/L
MW-11 07/11/2023 Uranium 2.80 ug/L
MW-37 08/11/2011 Chloride 55.0 mg/L
MW-37 10/19/2011 Chloride 50.0 mg/L
MW-37 02/29/2012 Chloride 36.0 mg/L
MW-37 05/29/2012 Chloride 50.0 mg/L
MW-37 07/30/2012 Chloride 51.0 mg/L D
MW-37 12/05/2012 Chloride 46.6 mg/L
MW-37 03/20/2013 Chloride 44.5 mg/L
MW-37 06/03/2013
Appendix B
Chloride 48.8 mg/L
Source Assesment Report for MW-11 and MW-37 ~INTERA White Mesa Uranium Mill Page 15 of 37
Appendix B-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
I Well I Sample Date I Parameter I Result ' Units ! Qualifier i 1----• - --~ __J -------~
MW-37 07/23/2013 Chloride 43.2 mg/L
MW-37 12/18/2013 Chloride 46.1 mg/L
MW-37 03/20/2014 Chloride 45.1 mg/L
MW-37 06/18/2014 Chloride 45.1 mg/L
MW-37 09/17/2014 Chloride 44.0 mg/L
MW-37 12/03/2014 Chloride 39.9 mg/L
MW-37 03/05/2015 Chloride 46.9 mg/L
MW-37 06/24/2015 Chloride 46.4 mg/L
MW-37 08/11/2015 Chloride 53.3 mg/L
MW-37 12/09/2015 Chloride 47.2 mg/L
MW-37 03/22/2016 Chloride 42.7 mg/L
MW-37 05/18/2016 Chloride 49.4 mg/L
MW-37 09/21/2016 Chloride 46.4 mg/L
MW-37 11/16/2016 Chloride 49.5 mg/L
MW-37 03/07/2017 Chloride 45.7 mg/L
MW-37 05/25/2017 Chloride 47.3 mg/L
MW-37 09/25/2017 Chloride 46.5 mg/L
MW-37 11/08/2017 Chloride 46.3 mg/L
MW-37 05/03/2018 Chloride 50.5 mg/L
MW-37 10/30/2018 Chloride 42.1 mg/L
MW-37 05/15/2019 Chloride 48.7 mg/L
MW-37 11/22/2019 Chloride 44.3 mg/L
MW-37 04/21/2020 Chloride 45.0 mg/L
MW-37 10/27/2020 Chloride 43.1 mg/L
MW-37 05/12/2021 Chloride 44.5 mg/L
MW-37 11/17/2021 Chloride 44.4 mg/L
MW-37 05/17/2022 Chloride 46.4 mg/L
MW-37 11/01/2022 Chloride 44.2 mg/L
MW-37 05/11/2023 Chloride 45.2 mg/L
MW-37 08/11/2011 Fluoride 0.300 mg/L
MW-37 10/19/2011 Fluoride 0.230 mg/L
MW-37 02/29/2012 Fluoride 0.250 mg/L
MW-37 05/29/2012 Fluoride 0.240 mg/L
MW-37 07/30/2012 Fluoride 0.220 mg/L
MW-37 12/05/2012 Fluoride 0.229 mg/L
MW-37 03/20/2013 Fluoride 0.268 mg/L
MW-37 06/03/2013 Fluoride 0.274 mg/L
MW-37 07/23/2013 Fluoride 0.284 mg/L
MW-37 12/18/2013 Fluoride 0.240 mg/L
MW-37 03/20/2014 Fluoride 0.324 mg/L
MW-37 06/18/2014 Fluoride 1.000 mg/L u
MW-37 09/17/2014 Fluoride 0.300 mg/L
MW-37 12/03/2014 Fluoride 0.221 mg/L
MW-37 03/05/2015 Fluoride 0.314 mg/L
MW-37 06/24/2015 Fluoride 0.290 mg/L
MW-37 08/11/2015 Fluoride 0.100 mg/L u
MW-37 12/09/2015 Fluoride 0.275 mg/L
MW-37 03/22/2016 Fluoride 0.386 mg/L
Appendix B
Source Assesment Report for MW-11 and MW-37 B INTERA White Mesa Uranium Mill Page 16 of 37
Appendix 8-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
. _Well__ Sample Date i Param~ter I ~suit ::.___~ ~ ~ _ ~~
MW-37 05/18/2016 Fluoride 0.322 mg/L
MW-37 09/21/2016 Fluoride 0.318 mg/L
MW-37 11/16/2016 Fluoride 0.218 mg/L
MW-37 03/07/2017 Fluoride 0.252 mg/L
MW-37 05/25/2017 Fluoride 0.228 mg/L
MW-37 09/25/2017 Fluoride 0.433 mg/L
MW-37 11/08/2017 Fluoride 0.307 mg/L
MW-37 05/03/2018 Fluoride 0.263 mg/L
MW-37 10/30/2018 Fluoride 0.255 mg/L
MW-37 05/15/2019 Fluoride 0.294 mg/L
MW-37 11/22/2019 Fluoride 0.106 mg/L
MW-37 04/21/2020 Fluoride 0.195 mg/L
MW-37 10/27/2020 Fluoride 0.257 mg/L
MW-37 05/12/2021 Fluoride 0.239 mg/L
MW-37 11/17/2021 Fluoride 0.229 mg/L
MW-37 05/17/2022 Fluoride 0.200 mg/L
MW-37 11/01/2022 Fluoride 0.249 mg/L
MW-37 05/11/2023 Fluoride 0.166 mg/L
MW-37 08/11/2011 Sulfate 2440 mg/L D
MW-37 10/19/2011 Sulfate 2620 mg/L D
MW-37 02/29/2012 Sulfate 2500 mg/L D
MW-37 05/29/2012 Sulfate 2460 mg/L D
MW-37 07/30/2012 $ulfate 2700 mg/L D
MW-37 12/05/2012 Sulfate 1010 mg/L
MW-37 03/20/2013 Sulfate 2130 mg/L
MW-37 06/03/2013 Sulfate 2570 mg/L
MW-37 07/23/2013 Sulfate 2720 mg/L
MW-37 12/18/2013 Sulfate 2750 mg/L
MW-37 03/20/2014 Sulfate 2600 mg/L
MW-37 06/18/2014 Sulfate 2640 mg/L
MW-37 09/17/2014 Sulfate 2370 mg/L
MW-37 12/03/2014 Sulfate 2700 mg/L
MW-37 03/05/2015 Sulfate 2650 mg/L
MW-37 06/24/2015 Sulfate 2650 mg/L
MW-37 08/11/2015 Sulfate 2480 mg/L
MW-37 12/09/2015 Sulfate 2600 mg/L
MW-37 03/22/2016 Sulfate 2360 mg/L
MW-37 05/18/2016 Sulfate 2530 mg/L
MW-37 09/21/2016 Sulfate 2300 mg/L
MW-37 11/16/2016 Sulfate 2600 mg/L
MW-37 03/07/2017 Sulfate 2240 mg/L
MW-37 05/25/2017 Sulfate 2430 mg/L
MW-37 09/25/2017 Sulfate 2350 mg/L
MW-37 11/08/2017 Sulfate 2360 mg/L
MW-37 05/03/2018 Sulfate 2570 mg/L
MW-37 10/30/2018 Sulfate 2170 mg/L
MW-37 05/15/2019 Sulfate 2330 mg/L
MW-37 11/22/2019 Sulfate 2640 mg/L
Appendix B
Source Assesment Report for MW-11 and MW-37 ~INTERA White Mesa Uranium Mill Page 17 of 37
Appendix B-3: MW-11 and MW-37 Indicator Parameter Data Used for Analysis
1 Well _ _ _ Sample Da~ ___ •---
MW-37 04/21/2020
MW-37 10/27/2020
MW-37 05/12/2021
MW-37 11/17/2021
MW-37 05/17/2022
MW-37 11/01/2022
MW-37 05/11/2023
MW-37 08/11/2011
MW-37 10/19/2011
MW-37 02/29/2012
MW-37 05/29/2012
MW-37 07/30/2012
MW-37 12/05/2012
MW-37 03/20/2013
MW-37 06/03/2013
MW-37 07/23/2013
MW-37 12/18/2013
MW-37 03/20/2014
MW-37 06/18/2014
MW-37 09/17/2014
MW-37 12/03/2014
MW-37 03/05/2015
MW-37 06/24/2015
MW-37 08/11/2015
MW-37 12/09/2015
MW-37 03/22/2016
MW-37 05/18/2016
MW-37 09/21/2016
MW-37 11/16/2016
MW-37 03/07/2017
MW-37 05/25/2017
MW-37 09/25/2017
MW-37 11/08/2017
MW-37 05/03/2018
MW-37 10/30/2018
MW-37 05/15/2019
MW-37 11/22/2019
MW-37 04/21/2020
MW-37 10/27/2020
MW-37 05/12/2021
MW-37 11/17/2021
MW-37 05/17/2022
MW-37 11/01/2022
MW-37 05/11/2023
Appendix B
Source Assesment Report for MW-11 and MW-37
White Mesa Uranium Mill
-
Parameter , ~ _ Units ___ Qualifier _
Sulfate 2510 mg/L
Sulfate 2460 mg/L
Sulfate 2570 mg/L
Sulfate 2560 mg/L
Sulfate 2340 mg/L
Sulfate 2280 mg/L
Sulfate 2580 mg/L
Uranium 18.1 ug/L
Uranium 15.6 ug/L
Uranium 12.3 ug/L
Uranium 10.9 ug/L
Uranium 12.4 ug/L
Uranium 15.5 ug/L
Uranium 10.3 ug/L
Uranium 12.3 ug/L
Uranium 12.8 ug/L
Uranium 11.4 ug/L
Uranium 11.6 ug/L
Uranium 11.8 ug/L
Uranium 10.7 ug/L
Uranium 12.0 ug/L
Uranium 13.9 ug/L
Uranium 14.1 ug/L
Uranium 16.1 ug/L
Uranium 13.9 ug/L
Uranium 13.8 ug/L
Uranium 13.6 ug/L
Uranium 13.2 ug/L
Uranium 13.6 ug/L
Uranium 13.6 ug/L
Uranium 12.7 ug/L
Uranium 16.2 ug/L
Uranium 14.5 ug/L
Uranium 10.5 ug/L
Uranium 12.1 ug/L
Uranium 11.5 ug/L
Uranium 11.6 ug/L
Uranium 11.6 ug/L
Uranium 11.9 ug/L
Uranium 12.0 ug/L
Uranium 10.9 ug/L
Uranium 11.5 ug/L
Uranium 12.0 ug/L
Uranium 11.7 ug/L
Page 18 of 37 B INTERA
Appendix 8-5: Box Plots for Indicator Parameters in MW-11 and MW-37
I Sulfate in MW-11 for Aif Data ; I - ----------~ -• ----
-....J --Cl E .._..
Q) -~ :::, en
:::. --Cl .s
Q) -~ :::,
Cl)
Appendix B
2000
1500
1000
500
0
Sulfate in MW-11
•
8
•
Percent nondetect: 0%
o Outlier
• Extreme
Min: 79, Mean: 1107.63, Max: 2250, Std Dev: 184.55
Upper extreme threshold (Q75 + 3xH): 1745
Lower extreme threshold (Q25 -3xH): 450
_ ~ulf~!~ fu]\4VV-11 Post July, 2019 -_ :
1400
1300
1200
1100
1000
900
Sulfate in MW-11
Percent nondetect: 0%
o Outlier
• Extreme
Min: 858, Mean: 1240.72, Max: 1470, Std Dev: 124.28
Upper extreme threshold (075 + 3xH): 1755
Lower extreme threshold (025 -3xH): 740
Source Assessment Report for MW-11 and MW-37 BINTERA White Mesa Uranium Mill Page 22 of 37
Appendix 8-5: Box Plots for Indicator Parameters in MW-11 and MW-37
I _ l,Jr~_ni_um 1~ _I\IIW-11 for All Data _ _ ---~ _
4
::::. 3 --C)
2..
E 2 ::::,
C ro ...
:::J 1
0
Uranium in MW-11
• o Outlier
• Extreme ' §
8
Percent nondetect: 19%
Min: 3e-04, Mean: 0.92, Max: 4, Std Dev: 0.67
Upper extreme threshold (Q75 + 3xH): 2.9641044776
Lower extreme threshold (Q25 -3xH): -1.5143283582
----------
I Uran!~~-l n MW-11 Post July, 2019 _ _ _ :
:::::i' --C)
2..
E ::J ·2: "' L. ::,
Appendix B
2.5
2.0
1.5
1.0
Uranium in MW-11
Percent nondetect: 0%
o Outlier
♦ Extreme
Min: 0.824, Mean: 1.76, Max: 2.8, Std Dev: 0.68
Upper extreme threshold (075 + 3xH): 6.36
Lower extreme threshold (025 -3xH): -2.88
Source Assessment Report for MW-11 and MW-37 ~-:.INTERA White Mesa Uranium Mill Page 23 of 37
Appendix B-5: Box Plots for Indicator Parameters in MW-11 and MW-37
I . _ . _ Chloride ~n -~yY-3? f~r A.l!Qata_ _ I
55
-50 ....J --C) g
Q) 45 "C ·.:::: ..Q .c
(.) 40
Chloride in MW-37
0
Percent nondetect: 0%
o Outlier
• Extreme
Min: 36, Mean: 46.25, Max: 55, Std Dev: 3.55
Upper extreme threshold (Q75 + 3xH): 61.6
Lower extreme threshold (Q25 -3xH): 31.5
----·
1 _Flu~ride in MW-~7 for AJ!_ ~~ta _ 1
1.0
::i" 0.8 --Cl .s 0.6 Q)
"C ·.:: 0 0.4 ~
LI.
0.2
Appendix B
Fluoride in MW-37
•
0
0
Percent nondetect: 5%
o Outlier
♦ Extreme
Min: 0.1, Mean: 0.28, Max: 1, Std Dev: 0.14
Upper extreme threshold (075 + 3xH): 0.513
Lower extreme threshold (Q25 -3xH): 0.0160000000000001
Source Assessment Report for MW-11 and MW-37 l!f!INTERA White Mesa Uranium Mill Page 24 of 37
Appendix B-7: Timeseries Plots for Indicator Parameters in MW-11 and MW-37
--
Sulfate in MW-37 for All Data --~ - --------~--------------
Sulfate in MW-37
• ® © ®• ®11t@ • 8 @ -@ ® ® ® (I • ~ 2500 @ ®@I) i) • (j
® (j @. CJ) ®. ® @@
_§, 2000 @ @
Q) _..
~ 1500 ::J
Cl)
1000 0
2012 2014 2016 2018 2020 2022
Sample Date
Uranium in MW-37 for All Data ~------------------------ --
Uranium in MW-37
r = -0.3251 p = 0.0496 r2 = 0.1057
-18 ....J --CJ) 16 @ ® ::J -E 14 @® @~ O @
@
::J
1l
© C ®@ co 12 ®•® ® ,_ ® @) s => ~ @ ® 10
2012 2014 2016 2018 2020 2022
Sample Date
Appendix B
Source Assessment Report for MW-11 and MW-37
White Mesa Uranium Mill Page 37 of 37 BINTERA
APPENDIXC
Table C.1
Predicted MW-11 Concentrations Based on a Mass Balance Assuming a
TMS lmpact1
average 2predicted Q2, 2023 measured
constituent concentration in MW-11
constituent concentration in TMS assuming TMS impact
chloride (mg/L) 28,108 10,443
fluoride (mg/L) 3,419 1,265
sulfate (mg/L) 179,486 67,254
uranium (ug/L) 388,419 143,717
selenium (ug/L) 9,296 3,449
1 assumes water level increase at MW-11 due to TMS impact
2 assumes conservative behavior (no sorption, hydrodynamic dispersion or degradation)
mg/L = milligrams per liter
ug/L = micrograms per liter
concentration
in MW-11
69
0.28
1,340
2.6
15.3
Table C.2
Predicted MW-37 Concentrations Based on a Mass Balance Assuming a
TMS lmpact1
average 2predicted Q2, 2023 measured
constituent concentration in MW-37
constituent concentration in TMS assuming TMS impact
chloride (mg/L) 28,108 14,077
fluoride (mg/L) 3,419 1,710
sulfate (mg/L) 179,486 91,033
uranium (ug/L) 388,419 194,215
1 assumes water level increase at MW-37 due to TMS impact
2 assumes conservative behavior (no sorption, hydrodynamic dispersion or degradation)
mg/L = milligrams per liter
ug/L = micrograms per liter
concentration
in MW-37
45
0.17
2,580
11.7
APPENDIXD
APPENDIXE
Input and Output Files (Electronic Only)