DRC-2021-003061 - 0901a06880e2605c

DIV of Waste Management
and Radation Control
Energy Fuels ResourceMA L2021
225 Union Blvd. Suite 600
Lakewood, CO, US, 80228
303 974 2140
F? C- 2 2 -00 3o I www.energyfuels.com
March 4, 2021
Sent VIA E-MAIL AND EXPEDITED DELIVERY
Mr. Ty L. Howard
Division of Waste Management and Radiation Control
Utah Department of Environmental Quality
195 North 1950 West
Salt Lake City, UT 84116
Re: Background Report for Monitoring Wells MW-38, MW-39, and MW-40
Groundwater Quality Discharge Permit UGW370004 White Mesa Uranium Mill
Dear Mr. Howard:
Enclosed are two copies of the White Mesa Uranium Mill Background Report for monitoring wells MW-38,
MW-39, and MW-40 as required by the Groundwater Quality Discharge Permit UGW370004. Also enclosed
are two CDs, each containing a word searchable electronic copy of the report and the associated appendices.
As noted above, these wells have been sampled quarterly since fourth quarter 2018. The GWDP requires the
completion of a Background Report after the collection of eight quarters of data. Analysis of the data, after
eight consecutive quarters, and a total of nine data points, indicate that additional data were required to meet the
statistical requirements of the flowsheet. Specifically, eight statistically valid points (as required by the
flowsheet) were not available for Gross Alpha (minus Rn and U) ("Gross Alpha") and manganese in MW-39
and chloride in MW-40 after the collection of eight quarters of data. Data collection continued until sufficient
data were available to complete the background analyses. This Background Report meets the requirements of
Section I.H.3c) for wells MW-38, MW-39 and MW-40.
If you should have any questions regarding this letter, please contact me.
Yours very truly,
cf
1214
ENERGY FUELS RESOURCES (USA) INC.
Kathy Weinel
Quality Assurance Manager
cc: David Frydenlund
Scott Bakken
Logan Shumway
Terry Slade
Garrin Palmer
Tanner Holliday
BACKGROUND GROUNDWATER QUALITY
REPORT FOR MONITORING WELLS MW-38,
MW-39, AND MW-40
WHITE MESA URANIUM MILL
Blanding, Utah

Prepared for:
Energy Fuels Resources (USA) Inc.
225 Union Boulevard, Suite 600
Lakewood, CO 80228

Prepared by:
6000 Uptown Boulevard NE, Suite 220 Albuquerque, New Mexico 87110
March 4, 2021

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page ES-i Blanding, Utah March 4, 2021
EXECUTIVE SUMMARY
Monitoring wells (“MW”) MW-38, MW-39, and MW-40 were installed in 2018 southeast of the
tailings cells in accordance with Part I.H.2 of the GWDP (DWMRC, 2019). Since the completion
of these wells, they have been monitored on a routine frequency. The purpose of this
Background Report is to evaluate the data from these wells, establish background groundwater
quality conditions, and determine groundwater compliance limits (“GWCLs”) for each
groundwater discharge permit constituent in each well.
Background at the White Mesa Uranium Mill (the “Mill”) site was recently thoroughly studied in
the previously submitted “Existing Wells Background Report” and “New Wells Background
Report” (INTERA, 2007; 2008), in the University of Utah Study (Hurst and Solomon, 2008), and
in multiple Source Assessment Reports (“SARs”) written in the last decade. These evaluations
concluded that groundwater at the Mill site has not been impacted by Mill operations. These
studies also acknowledged that there are natural processes at play that influence groundwater
concentrations and general variability of background groundwater at the site.
Groundwater sampling data from these new wells were analyzed according to the Flow Sheet
(from INTERA [2007a], included as Figure 2) that was approved by the State of Utah Division
of Waste Management and Radiation Control (“DWMRC”). At the time of the evaluation
performed for this Background Report, each data set contained 10 data points. Although a
minimum of eight data points are required according to the Flow Sheet, this number is 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 [“USEPA”]
statistical guidance [USEPA, 1992, revised 2009]).
Analysis of data collected to-date from MW-38, MW-39, and MW-40 confirms the variability of
constituents across the site and the region described in previous reports. Indicator parameters
chloride, fluoride, sulfate, and uranium are not exhibiting statistically significant increasing
trends, supporting the conclusions stated in previous Background Reports and investigations
performed at the site that groundwater at the site has not been impacted by Mill operations.
In accordance with the DWMRC-approved Flow Sheet, increasing trends necessitate a modified
approach for calculation of GWCLs. The modification proposed in this Background Report uses
the greatest value of established elements of the Flow Sheet approach or background x 1.5 as
discussed in the Utah Administrative Code (“UAC”) R-317-6-4.6 to determine representative
and appropriate GWCLs for trending constituents in Class III wells. Regular revisions to
GWCLs for constituents in wells with significantly increasing trends over time due to

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page ES-ii Blanding, Utah March 4, 2021
background is consistent with the USEPA statistical guidance (USEPA, 1992, revised 2009).
Such revisions account for the trends and minimize unwarranted out-of-compliance status in
such wells.

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page i Blanding, Utah March 4, 2021
TABLE OF CONTENTS
EXECUTIVE SUMMARY ..................................................................................................... ES-i
LIST OF FIGURES ...................................................................................................................... ii
LIST OF TABLES ........................................................................................................................ ii
LIST OF APPENDICES .............................................................................................................. ii
ABBREVIATIONS AND ACRONYMS .................................................................................... iii
1.0 INTRODUCTION............................................................................................................. 1
2.0 STATISTICAL ANALYSIS OF BACKGROUND GROUNDWATER QUALITY DATA ................................................................................................................................. 3
3.0 RESULTS OF ANALYSIS AND DETERMINATION OF GROUNDWATER COMPLIANCE LIMITS ................................................................................................. 5
3.1 Indicator Parameters ............................................................................................... 5 3.2 Trending Constituents ............................................................................................. 5 3.3 Groundwater Compliance Limits ............................................................................ 6
3.4 Modified Approach for Groundwater Compliance Limits for Trending
Constituents............................................................................................................. 6 3.4.1 Total Dissolved Solids ............................................................................... 7 3.4.2 Selenium .................................................................................................... 7 3.5 Hydraulic Properties ............................................................................................... 7
3.6 Relationship to Tailings Cells ................................................................................. 8
4.0 CONCLUSIONS ............................................................................................................... 9
5.0 REFERENCES ................................................................................................................ 10

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page ii Blanding, Utah March 4, 2021
LIST OF FIGURES
Figure 1 Location of Groundwater Monitoring Wells MW-38, MW-39, and MW-40 Figure 2 Groundwater Data Preparation and Statistical Process Flow for Calculating Groundwater Compliance Limits
Figure 3 Kriged 4th Quarter 2020 Water Levels Showing Local Pathlines for Hydraulic
Gradient Calculations LIST OF TABLES
Table 1 Monitoring Parameters and Groundwater Quality Standards Table 2 Laboratory Analytical Methods
Table 3 Comparison of Calculated and Measured TDS for Samples with Complete Major Ion Analysis Table 4 Charge Balance of Major Cations and Anions Table 5 Relative Percent Difference Between Primary and Duplicate Samples Table 6a Descriptive Summary Statistics for Constituents with Greater than 50 Percent Detects
Table 6b Descriptive Summary Statistics for Constituents with Less than 50 Percent Detects Table 7 Geometric Mean and Standard Deviation of Normally or Lognormally Distributed Data Table 8 Summary of Flow Sheet GWCL Calculations Based on UDEQ-Approved Flow Sheet Table 9 Hydraulic Properties of MW-38, MW-39, and MW-40
LIST OF APPENDICES
Appendix A Box Plots Appendix B Histograms and the Shapiro-Wilk Test for Data Sets with 0%-50% Non-Detects Appendix C Time Series Plots for All Constituents Showing Linear Regressions for Normal
and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit) Appendix D Probability Plots for Constituents with 0-50% Non-Detected Values (Non-Detected Values are Substituted with the Minimum Detection Limit) Appendix E Censored and Detected Values Only Probability Plots – Normally and
Lognormally Distributed Data Sets with 15% - 50% Non-Detected Values and
Summary of Descriptive Statistics and Trend Analysis for Censored Datasets Appendix F Data That Have Been Removed or Modified Prior to Statistical Analyses Appendix G Input and Output Files (Electronic Only)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page iii Blanding, Utah March 4, 2021
ABBREVIATIONS AND ACRONYMS
µg/L micrograms per liter
DRC State of Utah Division of Radiation Control
DWMRC Division of Waste Management and Radiation Control, State of Utah EFRI Energy Fuels Resources (USA) Inc. GWCL groundwater compliance limit
GWDP State of Utah Ground Water Discharge Permit UGW370004 HHV highest historical value INTERA INTERA Incorporated
mg/L milligrams per liter Mill White Mesa Uranium Mill MW monitoring well
ND non-detect value RPD Relative Percent Difference SAR Source Assessment Report
SD standard deviation TDS Total Dissolved Solids USEPA United States Environmental Protection Agency

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page 1 Blanding, Utah March 4, 2021
1.0 INTRODUCTION
Energy Fuels Resources (USA) Inc. (“EFRI”) operates the White Mesa Uranium Mill (the
“Mill”) located near Blanding, Utah, under State of Utah Ground Water Discharge Permit
UGW370004 (the “GWDP”).
Monitoring wells (“MWs”) MW-38, MW-39, and MW-40 (Figure 1) were installed far to the
southeast, cross-gradient of the tailings management system in February 2018, in accordance
with the January 18, 2018 GWDP. The wells have been monitored on a routine frequency since
installation. This Background Groundwater Quality Report for Monitoring Wells MW-38, MW-
39, and MW-40 (“Background Report”) at the Mill was prepared to meet the requirements stated
in Part I.H.3 of the Mill’s GWDP, issued by the State of Utah Division of Waste Management
and Radiation Control (“DWMRC” formerly DRC) on March 19, 2019:
3. Background Groundwater Quality Report for Wells MW-38, MW-39, MW-40 – within 30
calendar days of Director approval of the new monitoring well As-built Report, required by Part
I.H.2, above, the Permittee shall commence a quarterly groundwater sampling program that will
comply with the following Permit requirements: a) Routine groundwater compliance monitoring requirements of Part I.E.1. b) Well monitoring procedure requirements of Part I.E.5.
c) After completion of eight consecutive quarters of groundwater sampling and analysis of
wells MW-38, MW-39, MW-40 required by Part I.H.2, the Permittee shall submit a
Background Report for Director approval, that will include: 1) Data preparation and statistical analysis of groundwater quality data, including, but not limited to, evaluation of data characteristics and internal data consistency, treatment
of non-detectable values, and statistical methods used. These statistics shall be calculated
using the Decision Tree/Flowchart used for the previous Background Reports that was
conditionally approved by the DRC on August 24, 2007. 2) Shallow aquifer average linear groundwater velocity calculated for the new wells, based on well specific hydraulic conductivity, hydraulic gradient, and effective aquifer
porosity.
d) If after review of the report, and the Director determines that additional information is
required, the Permittee shall provide all requested information, resolve all issues identified, and re-submit the report for Director review and approval within a timeframe approved by the Director. After approval of this report, the Director will re-open this Permit and establish
an appropriate monitoring frequency with the criteria found in Part I.E.1(b). Designation of
these wells as “compliance” or “general” monitoring wells will be determined after analysis
of the Background Quality Groundwater Report. If the new wells are determined to be compliance wells, the Director will establish Groundwater Compliance Limits in Table 2 for wells MW-38, MW-39, MW-40.

This Background Report follows a similar format to the previously submitted Background
Reports:

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page 2 Blanding, Utah March 4, 2021
• Revised Background Groundwater Quality Report: Existing Wells for Denison Mines
(USA) Corp.’s Mill Site, San Juan County, Utah, October 2007, prepared by INTERA
Incorporated (“INTERA”) (INTERA, 2007a, the “Existing Wells Background Report”).
• Revised Addendum: Evaluation of Available Pre-Operational and Regional Background
Data, Background Groundwater Quality Report: Existing Wells for Denison Mines
(USA) Corp.’s Mill Site, San Juan County, Utah, November 16, 2007, prepared by
INTERA (INTERA, 2007b).
• Revised Addendum: Background Groundwater Quality Report: New Wells for Denison
Mines (USA) Corp.’s Mill Site, San Juan County, Utah (INTERA, 2008, the “New Wells
Background Report”).
• Background Groundwater Quality Report for Wells MW-20 and MW-22 for Denison
Mines (USA) Corp.’s White Mesa Mill Site, San Juan County, Utah, (INTERA, 2010).
• Background Groundwater Quality Report for Wells MW-35, MW-36, and MW-37 for
Energy Fuels Resources (USA) Inc.’s White Mesa Mill Site, San Juan County, Utah
(INTERA, 2014).
A description of the approach used for analysis is provided in Section 2.0, and the results of the
analysis are presented in Section 3.0. Conclusions and recommendations are reviewed in
Section 4.0, and references are included in Section 5.0.
The tables and appendices consist of the analyses performed for this assessment. The appendices
are organized in the following manner: Appendix A contains box and whisker plots for each
permit constituent and each well included in this Background Report. Appendix B contains
histograms of the log-transformed data along with results of the Shapiro-Wilk test for normality.
Appendix C contains the linear regression plots for each of the constituents in each well. The
plots for constituents that were detected less than 50% of the time are included for visual aid and
completeness and are considered exploratory statistics only. Appendix D contains probability
plots for constituents that include censored values (i.e., non-detect [“ND”] results). Appendix E
is the censored and detected value only probability plots for normally or lognormally distributed
constituents with 15% - 50% non-detected values, as well as the results from the Mann-Kendall
trend analysis for data sets that are not normally or lognormally distributed and have 0% - 90%
non-detected values. Appendix F is a table of data that have been removed prior to statistical
analysis. Appendix G is an electronic-only file that contains the input and output files used for
statistical analysis.

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page 3 Blanding, Utah March 4, 2021
2.0 STATISTICAL ANALYSIS OF BACKGROUND GROUNDWATER QUALITY DATA
In evaluating the data from MW-38, MW-39, and MW-40, an approach similar to the one
described in the New Wells Background Report (INTERA, 2008) was used. See that document
for a detailed discussion of methods used for the quality assurance evaluation of new data and
data validation. The New Wells Background Report (INTERA, 2008) summarized methods used
in a DWMRC-approved flow sheet (the “Flow Sheet,” from INTERA [2007a], included as
Figure 2) for the statistical analysis and the determination of the groundwater compliance limits
(“GWCLs”) for each constituent in each well that is presented in Figure 1 of this report. See the
Existing Wells Background Report (INTERA, 2007a) for a summary of historical operations and
a discussion of the geology and hydrology of the site.
The heterogeneity of groundwater quality at the site has been documented in several Background
Reports and Source Assessment Reports (“SARs”). Although a minimum of eight data points,
after data quality assurance steps have been performed, is required according to the Flow Sheet
(Figure 2), 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 [“USEPA”] statistical guidance [USEPA, 1992, revised 2009]). MW-38,
MW-39, and MW-40 have been sampled since installation for the GWDP constituents listed in
Table 1, resulting in 10 data points per constituent. Laboratory analytical methods for each
parameter are presented in Table 2. Groundwater monitoring results from MW-38, MW-39, and
MW-40 were subject to a quality assurance evaluation in accordance with the methods outlined
in the Flow Sheet. Internal consistency checks, including a comparison of measured and
calculated total dissolved solids (“TDS”) and charge balance of major cations and anions, are
presented in Tables 3 and 4, respectively. The relative percent difference (“RPD”) between
primary and duplicate samples are presented in Table 5. Creation of box and whisker plots to
identify and remove extreme outliers prior to statistical analysis was performed (Appendix A).
Descriptive statistics were calculated for all data sets and are presented in Tables 6a and 6b.
Table 7 presents the geometric mean and standard deviation (“SD”) of normally or lognormally
distributed data sets.
The process for calculating GWCLs was performed after each constituent that had at least
eight valid sample results following the Flow Sheet, with the results of each analysis summarized
in Table 8. The percentage of ND values was calculated for each data set. The statistical
distribution was determined by performing the Shapiro-Wilk test for normality on linear data sets
and log-transformed data sets. The results of this test for data sets with 0% - 50% NDs are
presented on the histograms in Appendix B and summarized in Table 8.

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page 4 Blanding, Utah March 4, 2021
Linear regression and Mann-Kendall trend analyses were performed on each constituent in each
well, as appropriate. For constituents that were normally or lognormally distributed, linear
regression analysis alone was performed (Appendix C). For constituents that were normally or
lognormally distributed with greater than 15% but less than or equal to 50% NDs, Mann-Kendall
trend analysis was also performed.
Time series plots for all constituents are shown in Appendix C. Linear regression analysis is also
shown in Appendix C for those data sets that are normal or lognormal. Some of the time series
plots in Appendix C should be considered as “exploratory statistics” for constituents with > 50%
NDs. Rising or decreasing trends identified by either linear regression (for normally or
lognormally distributed constituents having less than or equal to 50% NDs) or Mann-Kendall
analysis (for all non-parametric constituents and all constituents with greater than 15% NDs) and
are statistically significant are identified in Table 8. All other trends are not statistically
significant. See Sections 4.0, 5.0, and 6.0 of the Existing Wells Background Report (INTERA
2007a) for a full discussion of the statistical approaches used in this Background Report.

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page 5 Blanding, Utah March 4, 2021
3.0 RESULTS OF ANALYSIS AND DETERMINATION OF GROUNDWATER COMPLIANCE LIMITS
MW-38, MW-39, and MW-40 are Class III wells based on their TDS concentrations (all three of
the wells have mean concentrations of TDS that are greater than 3,000 milligrams per liter
[“mg/L”]) according to the rules set forth in UTAC R317-6-3.
3.1 Indicator Parameters
Chloride, sulfate, uranium, and fluoride have been identified as the best indicator parameters of
potential tailings cell seepage at the site, as described in Section 9.0 of the Existing Wells
Background Report (INTERA, 2007a). Review of the results for indicator parameters in each
well demonstrate that concentrations of indicator parameters in MW-38, MW-39, and MW-40
are not exhibiting significantly increasing trends (Appendix C, Table 8). Chloride, sulfate, and
uranium in MW-38 are not trending, and fluoride in MW-38 is decreasing slightly, though the
trend is not significant. Chloride, fluoride, and sulfate concentrations in MW-39 are stable to
decreasing slightly. Uranium in MW-39 is significantly decreasing. Chloride and uranium in
MW-40 are decreasing, and fluoride and sulfate in MW-40 are increasing slightly, but these
trends are not significant.
Evaluation of indicator parameters in MW-38, MW-39, and MW-40 supports the findings of
previous investigations at the Site, which conclude that there has been no impact to groundwater
from potential tailings cell seepage.
3.2 Trending Constituents
Trending constituents were identified by one of two trend test methods, according to the Flow
Sheet (Figure 2). Linear regression analysis was performed for normally or lognormally
distributed constituent data sets (Appendix C), and the Mann-Kendall trend test was performed
for the data sets which are not normally or lognormally distributed and contained 15% - 90%
NDs (Table 8). Statistically significant increasing trends include TDS in MW-38, potassium in
MW-39, and selenium in MW-40. Constituents that appear to exhibit increasing trends that are
not statistically significant include bicarbonate, and nitrate + nitrite, in MW-38; gross alpha,
thallium, and manganese in MW-39; and fluoride and sulfate in MW-40. In addition to the
constituents listed here, and despite the generally decreasing trend in pH observed sitewide, pH
in MW-38 and MW-40 is exhibiting an increasing trend. As described in Section 2.0, the
strength of statistical tests will increase with larger data sets, resulting in the potential for
trending concentrations in the future.

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page 6 Blanding, Utah March 4, 2021
3.3 Groundwater Compliance Limits
GWCLs were determined based on the DWMRC-approved Flow Sheet (Figure 2) and in a
similar manner to the previous Background Reports. GWCLs for constituents in MW-38, MW-
39, and MW-40 that were not exhibiting any increasing trends were determined by following the
Flow Sheet without any modifications. Table 8 contains a summary of the results of the Flow
Sheet along with the proposed GWCLs based on that analysis. The GWCLs included in Table 8
include mean + two standard deviations (mean + 2 SD), Cohen’s adjusted mean + 2 SD, highest
historical values (HHV), fractional, and Poisson Prediction Limits. The fractional approach
follows Utah Administrative Code (“UAC”) R-317-6-4.6 B(2), Cohen’s adjustment calculation
follows that outlined by the USEPA (2009) and the Poisson Prediction Limit is from USEPA
statistical guidance (1992). The Cohen’s adjustment and Poisson Prediction Limit calculations
are included in Appendix G.
3.4 Modified Approach for Groundwater Compliance Limits for Trending
Constituents
According to the DWMRC-approved Flow Sheet (Figure 2), if an increasing trend is present, a
modified approach should be considered for determining GWCLs for parameters listed in the
GWDP. Significant increasing trends in MW-38 (TDS) and MW-40 (selenium) can be attributed
to natural background conditions and are consistent with similar trends in other monitoring wells
at the Mill.
The UAC R317-6-4.6 recognizes that “contaminants” may be present as part of naturally
occurring background conditions:
When a contaminant is present in a detectable amount as a background
concentration, the concentration of the pollutant may not exceed the greater of
1.5 times the background concentration or 0.5 times the ground water quality
standard or background plus two standard deviations…
In this rule, background concentration is defined as the “concentration of a pollutant in ground
water upgradient or lateral hydraulically equivalent point from a facility, practice or activity
which has not been affected by that facility, practice or activity.” Therefore, to be conservative,
the mean concentration was used for the purposes of this calculation. The mean concentration
assumes all data to date for calculation steps in the Flow Sheet.
UAC R317-6-4.6 also states that TDS may not exceed the greater of 1.25 times the background
concentration or background plus two SDs. For this reason, the modified-approach GWCL for
TDS in MW-38 was calculated by multiplying the mean by 1.25. The modified-approach GWCL
for selenium in MW-40 was calculated by multiplying the mean by 1.5.

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page 7 Blanding, Utah March 4, 2021
Multiplying the mean concentrations of TDS and selenium by 1.25 and 1.5, respectively,
produces a GWCL that decreases the likelihood of false positives (exceedances) associated with
increasing trends related to natural background conditions.
The modified approach for trending constituents is summarized in Table 8 along with the
proposed GWCLs for all permit constituents and the rationale for determining their respective
GWCLs.
3.4.1 Total Dissolved Solids
TDS concentrations in MW-38 exhibit a statistically significant increasing trend (Appendix C,
Table 8), yet values are within normal site-wide ranges for TDS (Appendix B of the MW-31
SAR [INTERA, 2020]). Indicator parameter analyses for MW-38 supports previous conclusions
that there is no evidence of impact from potential tailings seepage.
The TDS data set is lognormally or normally distributed. The mean + 2SD is 4,301 mg/L, which
is 61 mg/L higher than the HHV of 4,240 mg/L. Because of the significant increasing trend, the
mean + 2SD GWCL is not appropriate and is likely to be exceeded in the future. Using the
modified approach described above, 1.25 times the mean concentration results in a GWCL of
5,009 mg/L.
3.4.2 Selenium
Selenium concentrations in MW-40 exhibit a statistically significant increasing trend
(Appendix C, Table 8). Selenium in MW-40 is within the range of concentrations for the site
(Appendix B of the MW-28 SAR [EFRI, 2020]). Indicator parameters chloride and uranium in
MW-40 are exhibiting decreasing trends, while fluoride and sulfate are increasing slightly. The
presence of an increasing trend in sulfate without an increasing trend in chloride, which is
considered the best indicator parameter, supports the conclusion that the increasing trend in
selenium is due to natural processes.
According to the Flow Sheet (Figure 2), the GWCL for selenium in MW-40 would be a mean +
2SD value of 212 micrograms per liter (“µg/L”) if no significant trend was present. Due to an
increasing trend the mean + 2SD is not appropriate for selenium in this well. The modified
approach GWCL is 241 µg/L, which is 1.5 times the mean, as defined in UAC R317-6-4.6.
Results of the modified approach for both data sets are summarized in Table 8.
3.5 Hydraulic Properties
Hydraulic testing and analysis of wells MW-38, MW-39, and MW-40 was performed and
documented by Hydro Geo Chem in the Installation and Hydraulic Testing As-Built Report
(HGC, 2018).

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page 8 Blanding, Utah March 4, 2021
The average linear perched groundwater pore velocity estimates for MW-38, MW-39, and MW-
40 are provided in Table 9. These estimates are calculated based on well-specific hydraulic
conductivities; the local hydraulic gradients; and the effective aquifer porosity. Figure 3
provides details used in calculating the local hydraulic gradients, which are based on fourth
quarter, 2020 water level measurements. Details regarding hydraulic conductivity estimation for
each well is provided in HGC (2018).
As shown in Table 9, the groundwater pore velocity estimates for MW-38, MW-39, and MW-
40, are 6.1, 1.4 and 10.2 feet per year, respectively. These estimates are consistent with the
generally slow movement of perched groundwater beneath the site.
3.6 Relationship to Tailings Cells
Based on the foregoing analysis, concentrations of constituents in groundwater samples from
MW-38, MW-39, and MW-40, which were installed far to the southeast and cross-gradient of the
tailings management system, have not been influenced by any potential seepage from the tailings
cells. The variability in data for MW-38, MW-39, and MW-40 is consistent with and reinforces
conclusions drawn from previous Background Reports and investigations performed at the site.

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page 9 Blanding, Utah March 4, 2021
4.0 CONCLUSIONS
Background at the Mill site was recently thoroughly studied in previous Background Reports, in
the University of Utah Study (Hurst and Solomon, 2008), and in several SARs. All of these
investigations concluded that groundwater at the site has not been impacted by Mill operations.
An investigation into the decreasing trends in pH at the site concluded that oxidation of pyrite in
the bedrock is contributing to decreasing pH and, in turn, mobilizing metals (HGC, 2012). These
studies also acknowledged that there are natural influences on groundwater concentration trends
and general variability of background groundwater at the site. Results for MW-38, MW-39, and
MW-40 are consistent with the variability of constituents across the site and the region described
in previous reports.
MW-38, MW-39, and MW-40 have relatively small data sets due to their recent installation and
limited sampling history. Based on previous experience with GWCLs for wells included in the
New Wells Background Report (INTERA, 2008) and the documented variability in natural
background conditions at the site, it is likely that background conditions are not being accurately
represented in MW-38, MW-39, and MW-40 at this time, and EFRI anticipates revisions to these
GWCLs, if necessary, as more data become available.
Increasing trends in some constituents have been identified. Indicator parameters for all of the
wells support the conclusion that these trends are not due to impacts from potential tailings cell
seepage. Based on the DWMRC-approved Flow Sheet (Figure 2), the indicated action for
trending constituents is “Consider Modified Approach to GWCL.” The modified approach,
which follows the USEPA statistical guidance along with established elements of the current
GWDP and UAC R317-6-4.6, has been applied to each of the trending constituents, resulting in
GWCLs that take naturally occurring trends into account.
A summary of proposed GWCLs based on the Flow Sheet or the modified approach is presented
in Table 8.

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page 10 Blanding, Utah March 4, 2021
5.0 REFERENCES
State of Utah Division of Waste Management and Radiation Control (DWMRC), 2019.
Groundwater Discharge Permit Number UGW370004. March 19.
Energy Fuels Resources (USA) Inc. (EFRI). 2020. White Mesa Uranium Mill State of Utah Groundwater Discharge Permit No. UGW370004 Source Assessment Report Under Part I.G.4 for Exceedances in MW-28 in the First Quarter of 2020. October 19.
Hurst, T.G., and Solomon, D.K., 2008. Summary of Work Completed, Data Results,
Interpretations and Recommendations for the July 2007 Sampling Event at the Denison
Mines, USA, White Mesa Uranium Mill Near Blanding Utah. Prepared by Department of Geology and Geophysics, University of Utah. May 2008.
Hydro Geo Chem, Inc. (HGC). 2012. Site Hydrology and Estimation of Groundwater Travel Times in the Perched Zone, White Mesa Uranium Mill Site Near Blanding, Utah.
Prepared for Denison Mines (USA) Corp. by Hydro Geo Chem Inc., July 10, 2012.
______. 2018. Installation and Hydraulic Testing of Perched Monitoring Wells MW-38, MW-39 and MW-40 White Mesa Uranium Mill Near Blanding, Utah (As-Built Report). June 12.
INTERA Incorporated (INTERA), 2007a. Revised Background Groundwater Quality Report: Existing Wells for Denison Mines (USA) Corp.’s White Mesa Mill Site, San Juan County,
Utah. October 2007 (“Existing Wells Background Report”).
––––––. 2007b. Revised Addendum: Evaluation of Available Pre-Operational and Regional Background Data, Background Groundwater Quality Report: Existing Wells for Denison Mines (USA) Corp.’s Mill Site, San Juan County, Utah, November 16.
______. 2008. Revised Addendum, Background Groundwater Quality Report: New Wells for
Denison Mines (USA) Corp’s White Mesa Mill Site, San Juan County, Utah.
______. 2010. Background Groundwater Quality Report for Wells MW-20 and MW-22 for Denison Mines (USA) Corp.’s White Mesa Mill Site, San Juan County, Utah, June 1.
______. 2014. Background Groundwater Quality Report for Wells MW-35, MW-36, and MW-37
for Energy Fuels Resources (USA) Inc.’s White Mesa Mill Site, San Juan County, Utah,
May 1.
______. 2020. Source Assessment Report for MW-31 White Mesa Uranium Mill, Blanding, Utah. June 24.
United States Environmental Protection Agency (USEPA). 1992. Statistical Analysis of Ground-
Water Monitoring Data at RCRA Facilities: Addendum to Interim Final Guidance.
Washington, D.C. Office of Solid Waste.

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Page 11 Blanding, Utah March 4, 2021
______.1992, revised 2009. Statistical Analysis of Groundwater Monitoring Data at RCRA
Facilities, Unified Guidance. EPA 530/R-09-007. Office of Resource Conservation and Recovery, Program Implementation and Information Division. March.

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Blanding, Utah
FIGURES
Cell No. 1
Cell No. 2
Cell No. 3
Cell No. 4A
Wild lifePond
Wild lifePond

Mill Site
Cell No. 4B
MW-31
MW-40
MW-39
MW-38
MW-37
MW-36
MW-34
MW-33
MW-32
MW-29
MW-28
MW-27
MW-26
MW-25
MW-24
MW-23
MW-22
MW-21
MW-20
MW-19
MW-18
MW-17MW-15
MW-12 MW-11MW-05
MW-04
MW-02
MW-01
MW-03A
MW-14
MW-30
MW-35
S:\ABQ\IUC-001-01-001 De nis on Mine s \GIS\mapd oc s \2020_Bac kground R pt\01_MW38_39_40_Loc ationMap.mxd Date : 3/1/2021
Figure 1Loc ation of Ground wate r MonitoringWe lls MW-38, MW-39, and MW-40White Me s a Uranium Mill
900 0 900
Fe e t
Sourc e (s ): Ae rial – ESR I Arc GIS online ;We lls – HGC, Inc ., May 2008 re port.
Ground wate r Monitoring We ll
IDAHOIDAHO
NEV
A
D
A
NEV
A
D
A
AR IZ ONAAR IZ ONA
WYOMINGWYOMING
UTAHUTAH
CO
L
O
R

A
D
O
CO
L
O
R

A
D
O
NEW MEXICONEW MEXICO
White Me s aUranium Mill
Negative Value?
Zero Value?
Truncated Value?
Duplicate Value?
Units Consistant?
Non-detects Exceeding Criteria Specified by URS Memo*
Analysis Internally Consistent?(TDS and Charge Balance Check)
YesNo
No
Yes
No
No
No
Yes
Yes
No
Yes
Yes
Yes
Radionuclide?
Yes
Remove from DatasetDetection Limit and U-Flag Data Qualifier NoNo
Review for Units
Remove from Dataset
If chloride, sulfate, or TDS, Remove from Dataset
Correct Value Confirmed?
Remove from
Dataset
Remove from Dataset
Determine Percentage Non-Detects in Remaining Data
Plot Data Sets as Box Plots to Identify Extreme Values As Specified in Background Report. Extreme Value?
No Remove from
Dataset
Yes
At Least 8 Data Points Remaining?
Defer Analysis Until Eight
Data Points Avalible
0-15 Percent Non-Detects >15-50 Percent Non-Detects >90 Percent Non-Detects
No
Yes
No
Substitute One Half of Detection Limit
Log Transform Data
Use Probability Plots to
Determine if Cohen’s or Aitchison’s Method
Calculate Descriptive Statistics
(Redo Tables In Background Report)
Screen for Trends Using Least Squares Regression.
Calculate GWCL (Mean
+2Sigma)
Calculate Descriptive Statistics
(Redo Tables In Background Report)
Yes
No
Calculate GWCL (Mean +2Sigma)
Calculate GWCL Using Greater of Fraction Approach under UAC R317-6-4-4.5(B)(2) or 4.6(B)(2) or Poisson Prediction Limit
Yes
No
>50-90 Percent Non-Detects
Calculate Upper Prediction Limit (Highest Historical Value)
Calculate GWCL Using Greater of Fraction Approach under UAC R317-6-4-4.5(B)(2) or 4.6(B)(2) or the Highest Historic Value
Estimate Mean and Standard
Deviation
Screen for Trends Using Mann-Kendall Screen for Trends Using Mann-Kendall
Yes
Use Non-Parametric StatisticsNo
Screen for Trends Using Least Squares Regression
Figure 2. Flowsheet
Groundwater Data Preparation and Statistical Process Flow for
Calculating Groundwater Protection Standards, White Mesa Mill Site, San Juan County, Utah
Upward Trend?Upward Trend?
No No
Yes
Consider Modified Approch to GWCL
Upward Trend?Upward Trend?
No No
Yes
Consider Modified Approch to GWCL
Log Transform Data
Log-Normal or Normal?Shapiro WilkProbability PlotsHistograms
Log-Normal or Normal?Shapiro WilkProbability PlotsHistograms
*A non-detect considered “insensitive” will be the maximum reporting limit in a dataset and will exceed other non-detects by, for example, an order of magnitude (e.g., <10 versus <1.0 µg/L). In some cases, insensitive non-detects may also exceed detectable values in a
dataset (e.g., <10 versus 3.5 µg/L).
Database of Wells and Analytes Listed in the Statement of Basis
HYDRO
GEO
CHEM, INC.
EXPLANATION
perched monitoring well showing
elevation in feet amsl
perched piezometer showing
elevation in feet amsl
seep or spring showing
elevation in feet amsl
KRIGED 4th QUARTER, 2020 WATER LEVELS
SHOWNG LOCAL PATHLINES FOR HYDRAULIC
GRADIENT CALCULATIONS
WHITE MESA SITE
H:/718000/MW38_39_40/
4Q2020PoreVelocities/Upath4Q20.srf
MW-5
PIEZ-1
RUIN SPRING
temporary perched monitoring well
showing elevation in feet amsl
temporary perched nitrate monitoring
well showing elevation in feet amsl
TW4-12
TWN-7
5504
5569
5568
5588
5380
5523
5463
TW4-40
TW4-42
local pathline for hydraulic
gradient calculations
3

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Blanding, Utah
TABLES

TABLE 1
Monitoring Parameters and Groundwater Quality Standards
Type Constituent GWQS Units
Nutrient Ammonia, N 25 mg/L
Nutrient Nitrate+Nitrite, N 10 mg/L
Metal Arsenic 50 µg/L
Metal Beryllium 4 µg/L
Metal Cadmium 5 µg/L
Metal Chromium 100 µg/L
Metal Cobalt 730 µg/L
Metal Copper 1,300 µg/L
Metal Iron 11,000 µg/L
Metal Lead 15 µg/L
Metal Manganese 800 µg/L
Metal Mercury 2 µg/L
Metal Molybdenum 40 µg/L
Metal Nickel 100 µg/L
Metal Selenium 50 µg/L
Metal Silver 100 µg/L
Metal Thallium 2 µg/L
Metal Tin 17,000 µg/L
Metal Uranium 30 µg/L
Metal Vanadium 60 µg/L
Metal Zinc 5,000 µg/L
Radiologic Gross Alpha 15 pCi/L
VOC Acetone 700 µg/L
VOC Benzene 5 µg/L
VOC 2-Butanone (Methyl Ethyl Ketone)4,000 µg/L
VOC Carbon Tetrachloride 5 µg/L
VOC Chloroform 70 µg/L
VOC Chloromethane 30 µg/L
VOC Dichloromethane (methylene chloride)5 µg/L
VOC Naphthalene 100 µg/L
VOC Tetrahydrofuran 46 µg/L
VOC Toluene 1,000 µg/L
VOC Total Xylenes 10,000 µg/L
Other Chloride TBD mg/L
Other Fluoride 4 mg/L
Other Field pH 6.5 to 8.5 pH
Other Sulfate TBD mg/L
Other TDS TBD mg/L
Notes:
mg/L = milligrams per liter
pCi/L = picocuries per liter
VOC = volatile organic compound
TBD = to be determined (defined as the value of the arithmetic mean plus two standard deviations or equivalent)
µg/L = micrograms per liter
TDS = total dissolved solids
GWQS = Ground Water Quality Standard (R317-6-2 Uah Administrative Code)
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 1
TABLE 2
Laboratory Analytical Methods
Sample Analysis Method
Chloride A4500-Cl B, E, E300.0
Fluoride A4500-F C, E300.0
Gross Alpha minus Rn and U E900.1
Iron
Manganese
Molybdenum
Nickel
Chromium
Cobalt
Vanadium
Tin
Zinc
E200.7
Mercury E245.1
All other Metals E200.8
Nitrogen
Ammonia as N A4500-NH3 G, E350.1, E353.2
Nitrogen
Nitrate + Nitrite as N E353.2
pH Field Parameter
Sulfate A4500-SO4 E, E300.0
Total Dissolved Solids A2540 C
Volatile Organic Compounds SW8260B
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 1
TABLE 3
Comparison of Calculated and Measured TDS
Well ID Date
Sampled
Alkalinity
(mg/L)
Calcium
(mg/L)
Chloride
(mg/L)
Potassium
(mg/L)
Magnesiu
m (mg/L)
Sodium
(mg/L)
Sulfate
(mg/L)
Measured TDS
(mg/L)
Calculated TDS
(mg/L)Ratio
MW-38 5/3/2018 135.42 505 45.5 29 191 440 2620 3910 3966 101%
MW-39 5/3/2018 1.22 449 40.8 13.1 199 544 3570 4460 4817 108%
MW-40 5/3/2018 363.56 429 53.9 9.28 182 354 2060 3390 3452 102%
MW-39 10/22/2018 1.22 512 35.9 13.8 223 595 2850 4150 4231 102%
MW-40 10/22/2018 306.22 492 40.7 9.49 205 395 2080 3480 3528 101%
MW-38 10/24/2018 137.86 555 40 30.3 207 488 2430 3770 3888 103%
MW-39 1/23/2019 1.22 515 36.6 13.4 223 604 3120 4280 4513 105%
MW-40 1/23/2019 314.76 490 41.8 8.95 210 383 1780 3600 3229 90%
MW-38 1/24/2019 124.44 531 43.1 29.2 210 474 2530 3870 3942 102%
MW-40 4/17/2019 341.60 463 47.1 9.52 199 381 2090 3480 3531 101%
MW-39 5/1/2019 1.22 515 40.1 14.6 226 602 2870 4200 4269 102%
MW-38 5/2/2019 143.96 559 44 30.3 220 509 2590 3910 4096 105%
MW-40 7/16/2019 314.76 526 42.7 8.93 219 364 2600 3410 4075 120%
MW-39 7/17/2019 1.22 511 41.3 14 219 555 3190 4140 4532 109%
MW-38 7/18/2019 134.20 551 46.5 29.2 212 465 2950 4070 4388 108%
MW-40 10/23/2019 283.04 486 43.4 8.46 212 367 2340 3680 3740 102%
MW-39 10/29/2019 1.22 445 41.7 15.2 195 516 3110 4210 4324 103%
MW-38 11/6/2019 124.44 483 43.7 41 195 410 2900 4110 4197 102%
MW-39 1/20/2020 1.22 475 40.4 14.4 190 476 3210 4560 4407 97%
MW-40 1/20/2020 429.44 446 43.1 9.53 194 369 2530 3760 4021 107%
MW-38 1/22/2020 169.58 469 46.1 28.3 182 502 3090 4240 4487 106%
MW-40 4/14/2020 322.08 475 43.5 9.65 204 399 2250 3280 3703 113%
MW-39 4/15/2020 1.22 470 39 15 204 568 2870 4140 4167 101%
MW-38 4/22/2020 124.44 490 44.7 28.6 200 460 2630 3950 3978 101%
MW-38 7/10/2020 148.84 529 38.4 33.3 206 525 2450 4160 3931 94%
MW-39 7/10/2020 1.22 491 35.3 16.2 213 631 2910 4380 4298 98%
MW-40 7/10/2020 353.80 503 35 10.4 211 408 2110 3510 3631 103%
MW-39 10/22/2020 1.22 494 36.2 14.5 215 552 3090 3640 4403 121%
MW-40 10/22/2020 324.52 465 35.6 8.06 197 340 2120 3110 3490 112%
MW-38 10/28/2020 146.40 458 43.4 28 180 444 2510 4080 3810 93%
Background Groundwater Quality Report for MW-38, MW-39, MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 1
TABLE 4
Charge Balance Calculations for Major Cations and Anions
Well Date Calcium
(meq/L)
Sodium
(meq/L)
Magnesium
(meq/L)
Potassium
(meq/L)
Total Cation
Charge
(meq/L)
HCO3
(meq/L)
Chloride
(meq/L)
SO4
(meq/L)
Total Anion
Charge
(meq/L)
Charge
Balance
Error
MW-38 5/3/2018 25.20 19.13 15.72 0.74 60.79 -2.22 -1.28 -54.55 -58.05 2.3%
MW-39 5/3/2018 22.41 23.65 16.38 0.34 62.77 -0.01 -1.15 -74.33 -75.49 -9.2%
MW-40 5/3/2018 21.41 15.39 14.98 0.24 52.02 -5.95 -1.52 -42.89 -50.36 1.6%
MW-39 10/22/2018 25.55 25.87 18.35 0.35 70.13 -0.01 -1.01 -59.34 -60.36 7.5%
MW-40 10/22/2018 24.55 17.17 16.87 0.24 58.84 -5.02 -1.15 -43.31 -49.47 8.7%
MW-38 10/24/2018 27.69 21.22 17.04 0.77 66.72 -2.26 -1.13 -50.59 -53.98 10.6%
MW-39 1/23/2019 25.70 26.26 18.35 0.34 70.66 -0.01 -1.03 -64.96 -66.00 3.4%
MW-40 1/23/2019 24.45 16.65 17.28 0.23 58.62 -5.15 -1.18 -37.06 -43.39 14.9%
MW-38 1/24/2019 26.50 20.61 17.28 0.75 65.14 -2.04 -1.22 -52.68 -55.93 7.6%
MW-40 4/17/2019 23.10 16.57 16.38 0.24 56.29 -5.59 -1.33 -43.51 -50.44 5.5%
MW-39 5/1/2019 25.70 26.17 18.60 0.37 70.85 -0.01 -1.13 -59.75 -60.89 7.6%
MW-38 5/2/2019 27.89 22.13 18.11 0.77 68.91 -2.36 -1.24 -53.92 -57.52 9.0%
MW-40 7/16/2019 26.25 15.83 18.02 0.23 60.33 -5.15 -1.20 -54.13 -60.49 -0.1%
MW-39 7/17/2019 25.50 24.13 18.02 0.36 68.01 -0.01 -1.17 -66.42 -67.59 0.3%
MW-38 7/18/2019 27.50 20.22 17.45 0.75 65.91 -2.20 -1.31 -61.42 -64.93 0.7%
MW-40 10/23/2019 24.25 15.96 17.45 0.22 57.87 -4.64 -1.22 -48.72 -54.58 2.9%
MW-39 10/29/2019 22.21 22.43 16.05 0.39 61.08 -0.01 -1.18 -64.75 -65.94 -3.8%
MW-38 11/6/2019 24.10 17.83 16.05 1.05 59.03 -2.04 -1.23 -60.38 -63.65 -3.8%
MW-39 1/20/2020 23.70 20.70 15.64 0.37 60.40 -0.01 -1.14 -66.83 -67.98 -5.9%
MW-40 1/20/2020 22.26 16.04 15.97 0.24 54.51 -7.03 -1.22 -52.68 -60.92 -5.6%
MW-38 1/22/2020 23.40 21.83 14.98 0.72 60.93 -2.78 -1.30 -64.33 -68.41 -5.8%
MW-40 4/14/2020 23.70 17.35 16.79 0.25 58.09 -5.27 -1.23 -46.85 -53.35 4.3%
MW-39 4/15/2020 23.45 24.70 16.79 0.38 65.32 -0.01 -1.10 -59.75 -60.86 3.5%
MW-38 4/22/2020 24.45 20.00 16.46 0.73 61.64 -2.04 -1.26 -54.76 -58.06 3.0%
Background Report MW-38, MW-39, MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 2
TABLE 4
Charge Balance Calculations for Major Cations and Anions
Well Date Calcium
(meq/L)
Sodium
(meq/L)
Magnesium
(meq/L)
Potassium
(meq/L)
Total Cation
Charge
(meq/L)
HCO3
(meq/L)
Chloride
(meq/L)
SO4
(meq/L)
Total Anion
Charge
(meq/L)
Charge
Balance
Error
MW-38 7/10/2020 26.40 22.83 16.95 0.85 67.03 -2.44 -1.08 -51.01 -54.53 10.3%
MW-39 7/10/2020 24.50 27.43 17.53 0.41 69.88 -0.01 -1.00 -60.59 -61.59 6.3%
MW-40 7/10/2020 25.10 17.74 17.37 0.27 60.47 -5.79 -0.99 -43.93 -50.71 8.8%
MW-39 10/22/2020 24.65 24.00 17.70 0.37 66.72 -0.01 -1.02 -64.33 -65.36 1.0%
MW-40 10/22/2020 23.20 14.78 16.21 0.21 54.41 -5.31 -1.00 -44.14 -50.46 3.8%
MW-38 10/28/2020 22.85 19.30 14.81 0.72 57.69 -2.40 -1.22 -52.26 -55.88 1.6%
Notes:
meq/L= milliequivalent per liter
HCO3 = Bicarbonate
SO4 = Sulfate
Background Report MW-38, MW-39, MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 2 of 2
TABLE 5
Relative Percent Difference Between Primary and Duplicate Samples
Well Constituent
Sample
Date Result Qualifier
Duplicate
Result
Duplicate
Qualifier Units
Relative
Percent
Difference
MW-39 Gross Alpha minus Rn and U 4/15/2020 2.62 2.66 pCi/L 1.52%
MW-39 Gross Alpha minus Rn and U 7/10/2020 3.15 3.47 pCi/L 9.67%
MW-40 Gross Alpha minus Rn and U 1/20/2020 1.26 1.23 pCi/L 2.41%
MW-40 Gross Alpha minus Rn and U 10/22/2020 1.89 1.33 pCi/L 34.78%
MW-40 Manganese 1/20/2020 115 112 µg/L 2.64%
MW-39 Manganese 4/15/2020 2240 2260 µg/L 0.89%
MW-39 Manganese 7/10/2020 2440 2410 µg/L 1.24%
MW-40 Manganese 10/22/2020 125 128 µg/L 2.37%
MW 35 Selenium 9/19/2012 8.2 9.7 µg/L 16.76%
MW-40 Selenium 1/20/2020 196 197 µg/L 0.51%
MW-39 Selenium 4/15/2020 5 U 5 U µg/L 0.00%
MW-39 Selenium 7/10/2020 5 U 5 U µg/L 0.00%
MW-40 Selenium 10/22/2020 184 184 µg/L 0.00%
MW-40 Thallium 1/20/2020 0.5 U 0.5 U µg/L 0.00%
MW-39 Thallium 4/15/2020 3.56 3.60 U µg/L 1.12%
MW-39 Thallium 7/10/2020 3.83 3.81 µg/L 0.52%
MW-40 Thallium 10/22/2020 0.5 U 0.5 U µg/L 0.00%
MW-40 Uranium 1/20/2020 23.1 23.4 µg/L 1.29%
MW-39 Uranium 4/15/2020 11.2 11.5 µg/L 2.64%
MW-39 Uranium 7/10/2020 11.8 12.3 µg/L 4.15%
MW-40 Uranium 10/22/2020 23.3 23.5 µg/L 0.85%
MW-40 Arsenic 1/20/2020 5 U 5 U µg/L 0.00%
MW-39 Arsenic 4/15/2020 5 U 5 U µg/L 0.00%
MW-39 Arsenic 7/10/2020 5 U 5 U µg/L 0.00%
MW-40 Arsenic 10/22/2020 5 U 5 U µg/L 0.00%
MW-40 Beryllium 1/20/2020 0.5 U 0.5 U µg/L 0.00%
MW-39 Beryllium 4/15/2020 4.99 4.92 µg/L 1.41%
MW-39 Beryllium 7/10/2020 4.18 4.26 µg/L 1.90%
MW-40 Beryllium 10/22/2020 0.5 U 0.5 U µg/L 0.00%
MW-40 Cadmium 1/20/2020 0.5 U 0.5 U µg/L 0.00%
MW-39 Cadmium 4/15/2020 2.66 2.65 µg/L 0.38%
MW-39 Cadmium 7/10/2020 2.73 2.73 µg/L 0.00%
MW-40 Cadmium 10/22/2020 0.5 U 0.5 U µg/L 0.00%
MW-40 Carbon tetrachloride 1/20/2020 1 U 1 U µg/L 0.00%
MW-39 Carbon tetrachloride 4/15/2020 1 U 1 U µg/L 0.00%
MW-39 Carbon tetrachloride 7/10/2020 1 U 1 U µg/L 0.00%
MW-40 Carbon tetrachloride 10/22/2020 1 U 1 U µg/L 0.00%
MW-40 Chloride 1/20/2020 43.1 43.1 mg/L 0.00%
MW-39 Chloride 4/15/2020 39.0 38.5 mg/L 1.29%
MW-39 Chloride 7/10/2020 35.3 39.0 mg/L 9.96%
MW-40 Chloride 10/22/2020 35.6 35.8 mg/L 0.56%
MW-40 Chloroform 1/20/2020 1 U 1 U µg/L 0.00%
MW-39 Chloroform 4/15/2020 1 U 1 U µg/L 0.00%
MW-39 Chloroform 7/10/2020 1 U 1 U µg/L 0.00%
MW-40 Chloroform 10/22/2020 1 U 1 U µg/L 0.00%
MW-40 Chloromethane 1/20/2020 1 U 1 U µg/L 0.00%
MW-39 Chloromethane 4/15/2020 1 U 1 U µg/L 0.00%
MW-39 Chloromethane 7/10/2020 1 U 1 U µg/L 0.00%
MW-40 Chloromethane 10/22/2020 1 U 1 U µg/L 0.00%
MW-40 Chromium 1/20/2020 25 U 25 U µg/L 0.00%
MW-39 Chromium 4/15/2020 25 U 25 U µg/L 0.00%
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 3
TABLE 5
Relative Percent Difference Between Primary and Duplicate Samples
Well Constituent
Sample
Date Result Qualifier
Duplicate
Result
Duplicate
Qualifier Units
Relative
Percent
Difference
MW-39 Chromium 7/10/2020 25 U 25 U µg/L 0.00%
MW-40 Chromium 10/22/2020 25 U 25 U µg/L 0.00%
MW-40 Cobalt 1/20/2020 10 U 10 U µg/L 0.00%
MW-39 Cobalt 4/15/2020 67.1 67.6 µg/L 0.74%
MW-39 Cobalt 7/10/2020 70.6 71.9 U µg/L 1.82%
MW-40 Cobalt 10/22/2020 10 U 10 U µg/L 0.00%
MW-40 Copper 1/20/2020 10 U 10 U µg/L 0.00%
MW-39 Copper 4/15/2020 28.0 28.5 µg/L 1.77%
MW-39 Copper 7/10/2020 28.3 28.9 µg/L 2.10%
MW-40 Copper 10/22/2020 10 U 10 U µg/L 0.00%
MW-40 Fluoride 1/20/2020 0.805 0.657 mg/L 20.25%
MW-39 Fluoride 4/15/2020 0.752 0.721 mg/L 4.21%
MW-39 Fluoride 7/10/2020 0.713 0.526 mg/L 30.19%
MW-40 Fluoride 10/22/2020 0.719 0.725 mg/L 0.83%
MW-40 Iron 1/20/2020 30 U 30 U µg/L 0.00%
MW-39 Iron 4/15/2020 14800 14900 µg/L 0.67%
MW-39 Iron 7/10/2020 14900 14700 µg/L 1.35%
MW-40 Iron 10/22/2020 41 30 U µg/L 30.99%
MW-40 Lead 1/20/2020 1 U 1 U µg/L 0.00%
MW-39 Lead 4/15/2020 1 U 1 U µg/L 0.00%
MW-39 Lead 7/10/2020 1 U 1 U µg/L 0.00%
MW-40 Lead 10/22/2020 1 U 1 U µg/L 0.00%
MW-40 Mercury 1/20/2020 0.5 U 0.5 U µg/L 0.00%
MW-39 Mercury 4/15/2020 0.5 U 0.5 U µg/L 0.00%
MW-39 Mercury 7/10/2020 0.5 U 0.5 U µg/L 0.00%
MW-40 Mercury 10/22/2020 0.5 U 0.5 U µg/L 0.00%
MW-40 Methyl ethyl ketone 1/20/2020 20 U 20 U µg/L 0.00%
MW-39 Methyl ethyl ketone 4/15/2020 20 U 20 U µg/L 0.00%
MW-39 Methyl ethyl ketone 7/10/2020 20 U 20 U µg/L 0.00%
MW-40 Methyl ethyl ketone 10/22/2020 20 U 20 U µg/L 0.00%
MW-39 Methylene chloride 7/10/2020 1 U 1 U µg/L 0.00%
MW-39 Methylene chloride 4/15/2020 1 U 1 U µg/L 0.00%
MW-40 Methylene chloride 1/20/2020 1 U 1 U µg/L 0.00%
MW-40 Methylene chloride 10/22/2020 1 U 1 U µg/L 0.00%
MW-40 Molybdenum 1/20/2020 10 U 10 U µg/L 0.00%
MW-39 Molybdenum 4/15/2020 10 U 10 U µg/L 0.00%
MW-39 Molybdenum 7/10/2020 10 U 10 U µg/L 0.00%
MW-40 Molybdenum 10/22/2020 10 U 10 U µg/L 0.00%
MW-40 Naphthalene 1/20/2020 1 U 1 U µg/L 0.00%
MW-39 Naphthalene 4/15/2020 1 U 1 U µg/L 0.00%
MW-39 Naphthalene 7/10/2020 1 U 1 U µg/L 0.00%
MW-40 Naphthalene 10/22/2020 1 U 1 U µg/L 0.00%
MW-40 Nickel 1/20/2020 20 U 20 U µg/L 0.00%
MW-39 Nickel 4/15/2020 33.2 33.9 µg/L 2.09%
MW-39 Nickel 7/10/2020 34.7 35.4 µg/L 2.00%
MW-40 Nickel 10/22/2020 20 U 20 U µg/L 0.00%
MW-40 Nitrate + Nitrite as N 1/20/2020 2.59 2.59 mg/L 0.00%
MW-39 Nitrate + Nitrite as N 4/15/2020 0.106 0.106 mg/L 0.00%
MW-39 Nitrate + Nitrite as N 7/10/2020 0.1 U 0.1 U mg/L 0.00%
MW-40 Nitrate + Nitrite as N 10/22/2020 2.5 2.4 mg/L 4.08%
MW-40 Nitrogen, Ammonia as N 1/20/2020 0.05 U 0.05 U mg/L 0.00%
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 2 of 3
TABLE 5
Relative Percent Difference Between Primary and Duplicate Samples
Well Constituent
Sample
Date Result Qualifier
Duplicate
Result
Duplicate
Qualifier Units
Relative
Percent
Difference
MW-39 Nitrogen, Ammonia as N 4/15/2020 0.260 0.267 mg/L 2.66%
MW-39 Nitrogen, Ammonia as N 7/10/2020 0.245 0.370 mg/L 40.65%
MW-40 Nitrogen, Ammonia as N 10/22/2020 0.05 U 0.05 U mg/L 0.00%
MW-40 Silver 1/20/2020 10 U 10 U µg/L 0.00%
MW-39 Silver 4/15/2020 10 U 10 U µg/L 0.00%
MW-39 Silver 7/10/2020 10 U 10 U µg/L 0.00%
MW-40 Silver 10/22/2020 10 U 10 U µg/L 0.00%
MW-40 Sulfate 1/20/2020 2530 2480 mg/L 2.00%
MW-39 Sulfate 4/15/2020 2870 3000 mg/L 4.43%
MW-39 Sulfate 7/10/2020 2910 2830 mg/L 2.79%
MW-40 Sulfate 10/22/2020 2120 2120 mg/L 0.00%
MW-40 Tetrahydrofuran 1/20/2020 1 U 1 U µg/L 0.00%
MW-39 Tetrahydrofuran 4/15/2020 1 U 1 U µg/L 0.00%
MW-39 Tetrahydrofuran 7/10/2020 1 U 1 U µg/L 0.00%
MW-40 Tetrahydrofuran 10/22/2020 1 U 1 U µg/L 0.00%
MW-40 Tin 1/20/2020 100 U 100 U µg/L 0.00%
MW-39 Tin 4/15/2020 100 U 100 U µg/L 0.00%
MW-39 Tin 7/10/2020 100 U 100 U µg/L 0.00%
MW-40 Tin 10/22/2020 100 U 100 U µg/L 0.00%
MW-40 Toluene 1/20/2020 1 U 1 U µg/L 0.00%
MW-39 Toluene 4/15/2020 1 U 1 U µg/L 0.00%
MW-39 Toluene 7/10/2020 1 U 1 U µg/L 0.00%
MW-40 Toluene 10/22/2020 1 U 1 U µg/L 0.00%
MW-40 Total Dissolved Solids 1/20/2020 3760 3470 mg/L 8.02%
MW-39 Total Dissolved Solids 4/15/2020 4140 4000 mg/L 3.44%
MW-39 Total Dissolved Solids 7/10/2020 4380 4100 mg/L 6.60%
MW-40 Total Dissolved Solids 10/22/2020 3110 3090 mg/L 0.65%
MW-40 Vanadium 1/20/2020 15 U 15 U µg/L 0.00%
MW-39 Vanadium 4/15/2020 15 U 15 U µg/L 0.00%
MW-39 Vanadium 7/10/2020 15 U 15 U µg/L 0.00%
MW-40 Vanadium 10/22/2020 15 U 15 U µg/L 0.00%
MW-40 Xylenes, Total 1/20/2020 1 U 1 U µg/L 0.00%
MW-39 Xylenes, Total 4/15/2020 1 U 1 U µg/L 0.00%
MW-39 Xylenes, Total 7/10/2020 1 U 1 U µg/L 0.00%
MW-40 Xylenes, Total 10/22/2020 1 U 1 U µg/L 0.00%
MW-40 Zinc 1/20/2020 10 U 10 U µg/L 0.00%
MW-39 Zinc 4/15/2020 233 238 µg/L 2.12%
MW-39 Zinc 7/10/2020 244 252 µg/L 3.23%
MW-40 Zinc 10/22/2020 10 U 10 U µg/L 0.00%
Notes:
µg/L = micrograms per liter
mg/L = milligrams per liter
pCi/L = picocuries per liter
Rn and U = radon and uranium
U (as qualifier) = result not detected above the laboratory reporting limit
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 3 of 3
TABLE 6a
Descriptive Summary Statistics for Constituents with Less than 50 Percent Non-Detects
Type Well Constituent Units N
% Non-
Detects Mean*Geometric
Mean
Std.
Dev.**Q25 Median Q75
Min.
Conc.
Max.
Conc.Range Skewness
ALL MW-39 Beryllium ug/l 10 0%4.99 4.97 0.49 4.69 4.99 5.12 4.18 5.94 1.76 0.47
ALL MW-39 Cadmium ug/l 10 0%2.72 2.71 0.14 2.65 2.71 2.80 2.43 2.97 0.54 -0.27
ALL MW-38 Chloride mg/l 10 0%43.54 43.47 2.58 43.18 43.85 45.30 38.40 46.50 8.10 -1.04
ALL MW-39 Chloride mg/l 10 0%38.73 38.66 2.48 36.30 39.55 40.70 35.30 41.70 6.40 -0.27
ER MW-40 Chloride mg/l 9 0%41.43 41.26 3.88 40.70 42.70 43.40 35.00 47.10 12.10 -0.71
ALL MW-39 Cobalt ug/l 10 0%68.24 68.05 5.46 66.35 67.35 70.55 59.30 79.80 20.50 0.63
ER MW-39 Copper ug/l 9 0%29.73 29.61 2.91 28.30 29.60 31.20 25.10 35.40 10.30 0.57
ALL MW-38 Fluoride mg/l 10 0%0.70 0.69 0.14 0.62 0.68 0.74 0.55 1.03 0.48 1.61
ER MW-39 Fluoride mg/l 9 0%0.69 0.69 0.06 0.65 0.70 0.72 0.61 0.81 0.20 0.48
ALL MW-40 Fluoride mg/l 10 0%0.69 0.69 0.08 0.64 0.68 0.75 0.55 0.81 0.26 -0.10
ER MW-39 Gross Alpha minus Rn and U pCi/L 9 0%3.22 3.07 1.13 2.59 2.96 3.15 2.09 5.11 3.02 1.19
ER MW-40 Gross Alpha minus Rn and U pCi/L 9 22%1.38 1.33 0.38 1.12 1.26 1.79 1.00 1.92 0.92 0.66
ER MW-39 Iron ug/l 9 0%14700.00 14695.08 403.11 14500.00 14600.00 14900.00 14000.00 15300.00 1300.00 -0.07
ER MW-39 Manganese ug/l 8 0%2203.75 2203.21 52.63 2177.50 2185.00 2202.50 2160.00 2320.00 160.00 1.91
ALL MW-40 Manganese ug/l 10 0%140.70 136.53 38.09 115.00 122.00 172.75 104.00 206.00 102.00 0.95
ALL MW-39 Nickel ug/l 10 0%33.59 33.48 2.83 32.60 33.80 35.23 29.00 38.40 9.40 -0.24
ALL MW-38 Nitrate + Nitrite as N mg/l 10 0%14.18 14.15 0.93 13.35 14.05 14.75 13.10 15.70 2.60 0.45
ER MW-39 Nitrate + Nitrite as N mg/l 9 33%0.11 0.11 0.02 0.10 0.11 0.11 0.10 0.17 0.07 2.48
ALL MW-40 Nitrate + Nitrite as N mg/l 10 0%2.82 2.81 0.29 2.65 2.75 2.88 2.50 3.52 1.02 1.64
ALL MW-39 Nitrogen, Ammonia as N mg/l 10 0%0.27 0.27 0.03 0.25 0.26 0.29 0.24 0.32 0.08 0.77
ALL MW-38 pH pH Units 10 0%7.14 7.13 0.23 7.03 7.14 7.27 6.67 7.45 0.78 -0.68
ER MW-39 pH pH Units 9 0%4.17 4.17 0.17 4.05 4.18 4.20 4.00 4.53 0.53 1.22
ALL MW-40 pH pH Units 10 0%6.76 6.76 0.25 6.62 6.81 6.94 6.30 7.06 0.76 -0.57
ALL MW-38 Selenium ug/l 10 0%163.20 163.03 7.77 158.75 165.50 166.75 148.00 175.00 27.00 -0.70
ALL MW-40 Selenium ug/l 10 0%160.50 158.53 25.86 147.25 154.00 182.50 112.00 196.00 84.00 -0.31
ALL MW-38 Sulfate mg/l 10 0%2670.00 2661.52 228.38 2515.00 2605.00 2832.50 2430.00 3090.00 660.00 0.89
ALL MW-39 Sulfate mg/l 10 0%3079.00 3072.09 221.53 2880.00 3100.00 3172.50 2850.00 3570.00 720.00 1.11
ALL MW-40 Sulfate mg/l 10 0%2196.00 2184.04 242.18 2082.50 2115.00 2317.50 1780.00 2600.00 820.00 0.27
ALL MW-39 Thallium ug/l 10 0%3.44 3.44 0.19 3.36 3.47 3.50 3.16 3.83 0.67 0.47
ALL MW-38 Total Dissolved Solids mg/l 10 0%4007.00 4004.57 147.05 3910.00 4010.00 4102.50 3770.00 4240.00 470.00 0.00
ALL MW-39 Total Dissolved Solids mg/l 10 0%4216.00 4209.11 248.74 4142.50 4205.00 4355.00 3640.00 4560.00 920.00 -1.19
ALL MW-40 Total Dissolved Solids mg/l 10 0%3470.00 3465.29 189.33 3395.00 3480.00 3577.50 3110.00 3760.00 650.00 -0.38
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 2
TABLE 6a
Descriptive Summary Statistics for Constituents with Less than 50 Percent Non-Detects
Type Well Constituent Units N
% Non-
Detects Mean*Geometric
Mean
Std.
Dev.**Q25 Median Q75
Min.
Conc.
Max.
Conc.Range Skewness
ALL MW-38 Uranium ug/l 10 0%6.39 6.38 0.38 6.03 6.49 6.75 5.80 6.78 0.98 -0.36
ALL MW-39 Uranium ug/l 10 0%12.02 11.99 0.97 11.50 11.75 12.25 10.90 14.20 3.30 1.39
ALL MW-40 Uranium ug/l 10 0%25.29 25.23 1.82 23.70 24.85 27.05 23.10 27.80 4.70 0.20
ER MW-39 Zinc ug/l 9 0%243.89 243.79 7.56 238.00 243.00 248.00 233.00 257.00 24.00 0.38
Notes:
Median = 50th percentile of the sample population.
Q75 = 75th percentile of the sample population.
Max. Conc. = maximum detected concentration.
µg/L = micrograms per liter.
mg/L = milligrams per liter.
All = entire data set.
pCi/L = picocuries per liter.
s.u.= standard units.
TDS = total dissolved solids.
Min. Conc. = minimum detected concentration.
N = number of data points in a data set.
Q25 = 25th percentile of the sample population.
Skewness = measure of skewness of the data distribution (Indicates the degree of assymetry and direction of the skewness. Values greater than 2 indicate significant skew, with negative
values indicating left skew, and positive values indicating right skew.).
% Non-Detects = the percent of non-detected values in a data set.
*Mean = arithmetic mean (For constituents with greater than 15% and less than 50% non-detects, means are determined in a separate manner in Table 8.)
ER = extreme outliers were removed prior to analysis.
**Std. Dev. = standard deviation (For constituents with greater than 15% and less than 50% non-detects, the standard deviation is determined in a separate manner in Table 8.)
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 2 of 2
TABLE 6b
Descriptive Summary Statistics for Constituents with Greater than 50 Percent Non-Detects
Type Well Constituent Units N
% Non-
Detects Mean*Geometric
Mean
Std.
Dev.**Q25 Median Q75
Min.
Conc.
Max.
Conc.Range Skewness
ALL MW-38 Acetone ug/l 10 100%20.00 20.00 0.00 20.00 20.00 20.00 20.00 20.00 0.00 NA
ALL MW-39 Acetone ug/l 10 100%20.00 20.00 0.00 20.00 20.00 20.00 20.00 20.00 0.00 NA
ALL MW-40 Acetone ug/l 10 100%20.00 20.00 0.00 20.00 20.00 20.00 20.00 20.00 0.00 NA
ALL MW-38 Arsenic ug/l 10 100%5.00 5.00 0.00 5.00 5.00 5.00 5.00 5.00 0.00 NA
ALL MW-39 Arsenic ug/l 10 100%5.00 5.00 0.00 5.00 5.00 5.00 5.00 5.00 0.00 NA
ALL MW-40 Arsenic ug/l 10 100%5.00 5.00 0.00 5.00 5.00 5.00 5.00 5.00 0.00 NA
ALL MW-38 Benzene ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-39 Benzene ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-40 Benzene ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-38 Beryllium ug/l 10 100%0.50 0.50 0.00 0.50 0.50 0.50 0.50 0.50 0.00 NA
ALL MW-40 Beryllium ug/l 10 100%0.50 0.50 0.00 0.50 0.50 0.50 0.50 0.50 0.00 NA
ALL MW-38 Cadmium ug/l 10 100%0.50 0.50 0.00 0.50 0.50 0.50 0.50 0.50 0.00 NA
ALL MW-40 Cadmium ug/l 10 100%0.50 0.50 0.00 0.50 0.50 0.50 0.50 0.50 0.00 NA
ALL MW-38 Carbon tetrachloride ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-39 Carbon tetrachloride ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-40 Carbon tetrachloride ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-38 Chloroform ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-39 Chloroform ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-40 Chloroform ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-38 Chloromethane ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-39 Chloromethane ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-40 Chloromethane ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-38 Chromium ug/l 10 100%25.00 25.00 0.00 25.00 25.00 25.00 25.00 25.00 0.00 NA
ALL MW-39 Chromium ug/l 10 100%25.00 25.00 0.00 25.00 25.00 25.00 25.00 25.00 0.00 NA
ALL MW-40 Chromium ug/l 10 100%25.00 25.00 0.00 25.00 25.00 25.00 25.00 25.00 0.00 NA
ALL MW-38 Cobalt ug/l 10 100%10.00 10.00 0.00 10.00 10.00 10.00 10.00 10.00 0.00 NA
ALL MW-40 Cobalt ug/l 10 100%10.00 10.00 0.00 10.00 10.00 10.00 10.00 10.00 0.00 NA
ALL MW-38 Copper ug/l 10 100%10.00 10.00 0.00 10.00 10.00 10.00 10.00 10.00 0.00 NA
ALL MW-40 Copper ug/l 10 100%10.00 10.00 0.00 10.00 10.00 10.00 10.00 10.00 0.00 NA
ER MW-38 Gross Alpha minus Rn and U pCi/L 9 67%1.06 1.05 0.10 1.00 1.00 1.11 1.00 1.30 0.30 1.99
ALL MW-38 Iron ug/l 10 100%30.00 30.00 0.00 30.00 30.00 30.00 30.00 30.00 0.00 NA
ALL MW-40 Iron ug/l 10 90%31.10 30.95 3.48 30.00 30.00 30.00 30.00 41.00 11.00 3.16
ALL MW-38 Lead ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-39 Lead ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-40 Lead ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-38 Manganese ug/l 10 100%10.00 10.00 0.00 10.00 10.00 10.00 10.00 10.00 0.00 NA
ALL MW-38 Mercury ug/l 10 100%0.50 0.50 0.00 0.50 0.50 0.50 0.50 0.50 0.00 NA
ALL MW-39 Mercury ug/l 10 100%0.50 0.50 0.00 0.50 0.50 0.50 0.50 0.50 0.00 NA
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 3
TABLE 6b
Descriptive Summary Statistics for Constituents with Greater than 50 Percent Non-Detects
Type Well Constituent Units N
% Non-
Detects Mean*Geometric
Mean
Std.
Dev.**Q25 Median Q75
Min.
Conc.
Max.
Conc.Range Skewness
ALL MW-40 Mercury ug/l 10 100%0.50 0.50 0.00 0.50 0.50 0.50 0.50 0.50 0.00 NA
ALL MW-38 Methyl ethyl ketone ug/l 10 100%20.00 20.00 0.00 20.00 20.00 20.00 20.00 20.00 0.00 NA
ALL MW-39 Methyl ethyl ketone ug/l 10 100%20.00 20.00 0.00 20.00 20.00 20.00 20.00 20.00 0.00 NA
ALL MW-40 Methyl ethyl ketone ug/l 10 100%20.00 20.00 0.00 20.00 20.00 20.00 20.00 20.00 0.00 NA
ALL MW-38 Methylene chloride ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-39 Methylene chloride ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-40 Methylene chloride ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-38 Molybdenum ug/l 10 80%10.35 10.31 1.04 10.00 10.00 10.00 10.00 13.30 3.30 3.14
ALL MW-39 Molybdenum ug/l 10 100%10.00 10.00 0.00 10.00 10.00 10.00 10.00 10.00 0.00 NA
ALL MW-40 Molybdenum ug/l 10 100%10.00 10.00 0.00 10.00 10.00 10.00 10.00 10.00 0.00 NA
ALL MW-38 Naphthalene ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-39 Naphthalene ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-40 Naphthalene ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-38 Nickel ug/l 10 100%20.00 20.00 0.00 20.00 20.00 20.00 20.00 20.00 0.00 NA
ALL MW-40 Nickel ug/l 10 100%20.00 20.00 0.00 20.00 20.00 20.00 20.00 20.00 0.00 NA
ALL MW-38 Nitrogen, Ammonia as N mg/l 10 70%0.05 0.05 0.01 0.05 0.05 0.05 0.05 0.07 0.02 1.54
ALL MW-40 Nitrogen, Ammonia as N mg/l 10 80%0.07 0.06 0.05 0.05 0.05 0.05 0.05 0.20 0.15 3.16
ALL MW-39 Selenium ug/l 10 100%5.00 5.00 0.00 5.00 5.00 5.00 5.00 5.00 0.00 NA
ALL MW-38 Silver ug/l 10 100%10.00 10.00 0.00 10.00 10.00 10.00 10.00 10.00 0.00 NA
ALL MW-39 Silver ug/l 10 100%10.00 10.00 0.00 10.00 10.00 10.00 10.00 10.00 0.00 NA
ALL MW-40 Silver ug/l 10 100%10.00 10.00 0.00 10.00 10.00 10.00 10.00 10.00 0.00 NA
ALL MW-38 Tetrahydrofuran ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-39 Tetrahydrofuran ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-40 Tetrahydrofuran ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-38 Thallium ug/l 10 100%0.50 0.50 0.00 0.50 0.50 0.50 0.50 0.50 0.00 NA
ALL MW-40 Thallium ug/l 10 90%0.51 0.51 0.03 0.50 0.50 0.50 0.50 0.60 0.10 3.16
ALL MW-38 Tin ug/l 10 100%100.00 100.00 0.00 100.00 100.00 100.00 100.00 100.00 0.00 NA
ALL MW-39 Tin ug/l 10 100%100.00 100.00 0.00 100.00 100.00 100.00 100.00 100.00 0.00 NA
ALL MW-40 Tin ug/l 10 100%100.00 100.00 0.00 100.00 100.00 100.00 100.00 100.00 0.00 NA
ALL MW-38 Toluene ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-39 Toluene ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-40 Toluene ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-38 Vanadium ug/l 10 100%15.00 15.00 0.00 15.00 15.00 15.00 15.00 15.00 0.00 NA
ALL MW-39 Vanadium ug/l 10 100%15.00 15.00 0.00 15.00 15.00 15.00 15.00 15.00 0.00 NA
ALL MW-40 Vanadium ug/l 10 100%15.00 15.00 0.00 15.00 15.00 15.00 15.00 15.00 0.00 NA
ALL MW-38 Xylenes, Total ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-39 Xylenes, Total ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
ALL MW-40 Xylenes, Total ug/l 10 100%1.00 1.00 0.00 1.00 1.00 1.00 1.00 1.00 0.00 NA
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 2 of 3
TABLE 6b
Descriptive Summary Statistics for Constituents with Greater than 50 Percent Non-Detects
Type Well Constituent Units N
% Non-
Detects Mean*Geometric
Mean
Std.
Dev.**Q25 Median Q75
Min.
Conc.
Max.
Conc.Range Skewness
ALL MW-38 Zinc ug/l 10 80%10.95 10.81 2.01 10.00 10.00 10.00 10.00 15.10 5.10 1.81
ALL MW-40 Zinc ug/l 10 80%15.72 12.21 17.71 10.00 10.00 10.00 10.00 66.10 56.10 3.16
Notes:
% Non-Detects = The percent of non-detected values in a data set.
µg/L = micrograms per liter.
Max. Conc. = maximum detected concentration.
Median = 50th percentile of the sample population.
mg/L = milligrams per liter.
Min. Conc. = minimum detected concentration.
pCi/L = picoCuries per liter.
Q25 = 25th percentile of the sample population.
Q75
s.u.= standard units.
TDS = total dissolved solids.
Skewness = measure of skewness of the data distribution (Indicates the degree of assymetry and direction of the skewness. Values greater than 2 indicate significant skew, with negative
values indicating left skew, and positive values indicating right skew.).
N = number of samples.
All = entire data set.
*Mean = Arithmetic mean; for constituents with greater than 15% and less than 50% non-detects, means used to calculate GWCLs are determined in a separate manner in Table 8.
**Std.Dev. = Standard deviation; for constituents with greater than 15% and less than 50% non-detects, the standard deviation is determined in a separate manner in Table 8.
ER = extreme outliers were removed prior to analysis.
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 3 of 3
TABLE 7
Geometric Mean and Standard Deviation of Normally or Log-Normally Distributed Data
Well Constituent GWQS N
% Non-
Detect
Geometric
Mean
Geometric
Standard
Deviation
MW-38 Chloride (mg/L)TBD 10 0% 43.47 2.58
MW-38 Fluoride (mg/L)4 10 0% 0.69 0.14
MW-38 Nitrate + Nitrite as N (mg/L)TBD 10 0% 14.15 0.93
MW-38 pH (s.u.)6.5 to 8.5 10 0% 7.13 0.23
MW-38 Selenium (µg/L)50 10 0% 163.03 7.77
MW-38 Sulfate (mg/L)TBD 10 0% 2,661.52 228.38
MW-38 Total Dissolved Solids (mg/L)TBD 10 0% 4,004.57 147.05
MW-38 Uranium (µg/L)30 10 0% 6.38 0.38
MW-39 Beryllium (µg/L)4 10 0% 4.97 0.49
MW-39 Cadmium (µg/L)5 10 0% 2.71 0.14
MW-39 Chloride (µg/L)5 10 0% 38.66 2.48
MW-39 Cobalt (µg/L)730 10 0% 68.05 5.46
MW-39 Copper (µg/L)1,300 9 0% 29.61 2.91
MW-39 Fluoride (mg/L)4 9 0% 0.69 0.06
MW-39 Gross Alpha minus Rn and U (pCi/L) 15 9 0% 3.07 1.13
MW-39 Iron (µg/L)11,000 9 0% 14,695.08 403.11
MW-39 Nickel (µg/L)100 10 0% 33.48 2.83
MW-39 Nitrogen, Ammonia as N (mg/L)25 10 0% 0.27 0.03
MW-39 pH (s.u.)25 9 0% 4.17 0.17
MW-39 Sulfate (mg/L)TBD 10 0% 3,072.09 221.53
MW-39 Thallium (µg/L)2 10 0% 3.44 0.19
MW-39 Total Dissolved Solids (mg/L)TBD 10 0% 4,209.11 248.74
MW-39 Uranium (µg/L)30 10 0% 11.99 0.97
MW-39 Zinc (µg/L)30 9 0% 243.79 7.56
MW-40 Chloride (mg/L)30 9 0% 41.26 3.88
MW-40 Fluoride (mg/L)4 10 0% 0.69 0.08
MW-40 Gross Alpha minus Rn and U (pCi/L) 15 9 0.22% 1.33 0.38
MW-40 Nitrate + Nitrite as N (mg/L)10 10 0% 2.81 0.29
MW-40 pH (s.u.)6.5 to 8.5 10 0% 6.76 0.25
MW-40 Selenium (µg/L)50 10 0% 158.53 25.86
MW-40 Sulfate (mg/L)TBD 10 0% 2,184.04 242.18
MW-40 Total Dissolved Solids (mg/L)TBD 10 0%3,465.29 189.33
MW-40 Uranium (µg/L)30 10 0% 25.23 1.82
Notes:
s.u. = standard units
µg/L = micrograms per liter
pCi/L = picoCuries per liter
TBD = to be determined (defined as the value of the arithmetic mean plus two standard deviations or equivalent)
GWQS= Ground Water Quality Standard (R317-6-2 Utah Administrative Code)
% Non-Detected = the percent of non-detected values in a data set
N = Number of data points
mg/L = milligrams per liter
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 1
TABLE 8
Summary of Flow Sheet GWCL Calculations Based on UDEQ-Approved Flow Sheet
r p r2 Sp Mean SD
MW-38 Ammonia 25 10 70% No 2 0.45567 0.0658 12.5 12.50 Fractional
MW-38 NitrateNitrite 10 10 0% Yes 0.59229 0.07121 0.3508 14.18 0.93190367 15.7 5 16.04 mean + 2SD
MW-38 Arsenic 50 10 100% Not Tested 5.71 25 25 Fractional
MW-38 Beryllium 4 10 100% Not Tested 1.39 2 2 Fractional
MW-38 Cadmium 5 10 100% Not Tested 1.39 2.5 2.5 Fractional
MW-38 Chromium 100 10 100% Not Tested 19.47 50 50 Fractional
MW-38 Cobalt 730 10 100% Not Tested 9.47 365 365 Fractional
MW-38 Copper 1300 10 100% Not Tested 9.47 650 650 Fractional
MW-38 Iron 11000 10 100% Not Tested 22.62 5500 5500 Fractional
MW-38 Lead 15 10 100% Not Tested 2.04 7.5 7.5 Fractional
MW-38 Manganese 800 10 100% Not Tested 9.47 400 400 Fractional
MW-38 Mercury 2 10 100% Not Tested 1.39 1 1.39 Poisson Prediction Limit
MW-38 Molybdenum 40 10 80% No 9 0.15018 13.3 20 20 Fractional
MW-38 Nickel 10 10 100% Not Tested 16.25 5 16.25 Poisson Prediction Limit
MW-38 Selenium 50 10 0% Yes -0.44623 0.19612 0.1991 163.2 7.77174369 175 25 178.74 mean + 2SD
MW-38 Silver 100 10 100% Not Tested 9.47 50 50 Fractional
MW-38 Thallium 2 10 100% Not Tested 1.39 1 1.39 Poisson Prediction Limit
MW-38 Tin 17000 10 100% Not Tested 63.76 8500 8500 Fractional
MW-38 Uranium 30 10 0% Yes -0.03859 0.91571 0.001 6.39 0.38464991 6.78 15 7.16 mean + 2SD
MW-38 Vanadium 60 10 100% Not Tested 12.94 30 30 Fractional
MW-38 Zinc 5000 10 80% No -15 0.03496 15.1 2500 2500 Fractional
MW-38 GrossAlpha 15 9 67% No 8 0.18828 1.3 7.5 7.50 Fractional
MW-38 Acetone 700 10 100% Not Tested 16.25 350 350 Fractional
MW-38 Benzene 5 10 100% Not Tested 2.04 2.5 2.5 Fractional
MW-38 Methyl ethyl ketone 4000 10 100% Not Tested 16.25 2000 2000 Fractional
MW-38 Carbon tetrachloride 5 10 100% Not Tested 2.04 2.5 2.5 Fractional
MW-38 Chloroform 70 10 100% Not Tested 2.04 35 35 Fractional
MW-38 Chloromethane 30 10 100% Not Tested 2.04 15 15 Fractional
MW-38 Methylene chloride 5 10 100% Not Tested 2.04 2.5 2.5 Fractional
MW-38 Naphthalene 100 10 100% Not Tested 2.04 50 50 Fractional
MW-38 Tetrahydrofuran 46 10 100% Not Tested 2.04 23 23 Fractional
MW-38 Toluene 1000 10 100% Not Tested 2.04 500 500 Fractional
MW-38 Xylenes, Total 10000 10 100% Not Tested 2.04 5000 5000 Fractional
MW-38 Chloride (mg/L) 10 0% Yes -0.1428 0.69391 0.0204 43.54 2.57992248 46.5 48.70 mean + 2SD
MW-38 Fluoride (mg/L) 4 10 0% Yes -0.51993 0.12345 0.2703 0.7027 0.1362653 1.03 2 0.98 mean + 2SD
MW-38 Field pH (s.u.) 10 0% Yes 0.62471 0.05349 0.3903 7.138 0.23006279 7.45 7.60 mean + 2SD
MW-38 Sulfate (mg/L) 10 0% Yes 0.09486 0.79436 0.009 2670 228.375908 3090 3126.75 mean + 2SD
MW-38 TDS (mg/L) 10 0% Yes 0.69321 0.02623 0.4805 Increasing 4007 147.048745 4240 4301.10 mean + 2SD 5008.75 1.25x mean
MW-39 Ammonia 25 10 0% Yes -0.61142 0.06035 0.3738 0.2718 0.02923012 0.319 12.5 0.33 mean + 2SD
MW-39 NitrateNitrite 10 9 33% No -23 0.00962 Decreasing 0.166 5 5 Fractional
MW-39 Nutrients (mg/L)
St. Dev. HHV
Poisson
Prediction
Limit 95%
Fractional
Approach
(Class III)
Cohen
Significant
Trend Mean
Flowsheet
GWCL
Flowsheet GWCL
Rationale
MW-38 Heavy Metals (µg/L)
MW-38 Radiologics (pCi/L)
MW-38 Volatile Organic Compounds (µg/L)
MW-38 Other
Proposed
Modified
GWCL
Modified
GWCL
Rationale
MW-38 Nutrients (mg/L)
Linear Regression
Significant
Trend
Mann-Kendall
Well Constituent GWQS N %ND
Normally or
Lognormally
Distributed?
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 3
TABLE 8
Summary of Flow Sheet GWCL Calculations Based on UDEQ-Approved Flow Sheet
r p r2 Sp Mean SDSt. Dev. HHV
Poisson
Prediction
Limit 95%
Fractional
Approach
(Class III)
Cohen
Significant
Trend Mean
Flowsheet
GWCL
Flowsheet GWCL
Rationale
Proposed
Modified
GWCL
Modified
GWCL
Rationale
Linear Regression
Significant
Trend
Mann-Kendall
Well Constituent GWQS N %ND
Normally or
Lognormally
Distributed?
MW-39 Arsenic 50 10 100% Not Tested 5.71 25 25 Fractional
MW-39 Beryllium 4 10 0% Yes -0.77461 0.00852 0.6 Decreasing 4.987 0.48958145 5.94 2 5.97 mean + 2SD
MW-39 Cadmium 5 10 0% Yes 0.08191 0.82201 0.0067 2.718 0.14366628 2.97 2.5 3.01 mean + 2SD
MW-39 Chromium 100 10 100% Not Tested 19.47 50 50 Fractional
MW-39 Cobalt 730 10 0% Yes -0.21467 0.55146 0.0461 68.24 5.46487776 79.8 365 79.17 mean + 2SD
MW-39 Copper 1300 9 0% Yes -0.65734 0.05436 0.4321 29.733 2.90989691 35.4 650 35.55 mean + 2SD
MW-39 Iron 11000 9 0% Yes 0.00339 0.9931 1E-05 14700 403.112887 15300 5500 15506.23 mean + 2SD
MW-39 Lead 15 10 100% Not Tested 2.04 7.5 7.5 Fractional
MW-39 Manganese 800 8 0% No 12 0.08345 2320 400 2320 HHV
MW-39 Mercury 2 10 100% Not Tested 1.39 1 1.39 Poisson Prediction Limit
MW-39 Molybdenum 40 10 100% Not Tested 9.47 20 20 Fractional
MW-39 Nickel 100 10 0% Yes -0.0184 0.95976 0.0003 33.59 2.82938941 38.4 50 39.25 mean + 2SD
MW-39 Selenium 50 10 100% Not Tested 5.71 25 25 Fractional
MW-39 Silver 100 10 100% Not Tested 9.47 50 50 Fractional
MW-39 Thallium 2 10 0% Yes 0.49431 0.14642 0.2443 3.444 0.18762847 3.83 1 3.82 mean + 2SD
MW-39 Tin 17000 10 100% Not Tested 63.76 8500 8500 Fractional
MW-39 Uranium 30 10 0% Yes -0.63932 0.04656 0.4087 Decreasing 12.02 0.96701143 14.2 15 13.95 mean + 2SD
MW-39 Vanadium 60 10 100% Not Tested 12.94 30 30 Fractional
MW-39 Zinc 5000 9 0% Yes -0.46668 0.20537 0.2178 243.89 7.55718937 257 2500 259.00 mean + 2SD
MW-39 GrossAlpha 15 9 0% Yes 0.52762 0.14432 0.2784 3.2189 1.12645955 5.11 7.5 5.47 mean + 2SD
MW-39 Acetone 700 10 100% Not Tested 16.25 350 350 Fractional
MW-39 Benzene 5 10 100% Not Tested 2.04 2.5 2.5 Fractional
MW-39 Methyl ethyl ketone 4000 10 100% Not Tested 16.25 2000 2000 Fractional
MW-39 Carbon tetrachloride 5 10 100% Not Tested 2.04 2.5 2.5 Fractional
MW-39 Chloroform 70 10 100% Not Tested 2.04 35 35 Fractional
MW-39 Chloromethane 30 10 100% Not Tested 2.04 15 15 Fractional
MW-39 Methylene chloride 5 10 100% Not Tested 2.04 2.5 2.5 Fractional
MW-39 Naphthalene 100 10 100% Not Tested 2.04 50 50 Fractional
MW-39 Tetrahydrofuran 46 10 100% Not Tested 2.04 23 23 Fractional
MW-39 Toluene 1000 10 100% Not Tested 2.04 500 500 Fractional
MW-39 Xylenes, Total 10000 10 100% Not Tested 2.04 5000 5000 Fractional
MW-39 Chloride (mg/L) 10 0% Yes -0.2481 0.48948 0.0616 38.73 2.47568172 41.7 43.68 mean + 2SD
MW-39 Fluoride (mg/L) 4 9 0% Yes 0.02712 0.94479 0.0007 0.692 0.06310903 0.805 2 0.82 mean + 2SD
MW-39 Field pH (s.u.) 9 0% Yes 0.07202 0.85392 0.0052 4.17 0.16889346 4.53 4.51 mean + 2SD
MW-39 Sulfate (mg/L) 10 0% Yes -0.40146 0.25018 0.1612 3079 221.532541 3570 3522.07 mean + 2SD
MW-39 TDS (mg/L) 10 0% Yes -0.41 0.2393 0.1681 4216 248.739042 4560 4713.48 mean + 2SD
MW-40 Ammonia 25 10 80% No -5 0.30229 0.2 12.5 12.5 Fractional
MW-40 NitrateNitrite 10 10 0% Yes -0.82519 0.00329 0.6809 Decreasing 2.822 0.29483705 3.52 5 3.41 mean + 2SD
MW-40 Nutrients (mg/L)
MW-39 Heavy Metals (µg/L)
MW-39 Radiologics (pCi/L)
MW-39 Volatile Organic Compounds (µg/L)
MW-39 Other
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 2 of 3
TABLE 8
Summary of Flow Sheet GWCL Calculations Based on UDEQ-Approved Flow Sheet
r p r2 Sp Mean SDSt. Dev. HHV
Poisson
Prediction
Limit 95%
Fractional
Approach
(Class III)
Cohen
Significant
Trend Mean
Flowsheet
GWCL
Flowsheet GWCL
Rationale
Proposed
Modified
GWCL
Modified
GWCL
Rationale
Linear Regression
Significant
Trend
Mann-Kendall
Well Constituent GWQS N %ND
Normally or
Lognormally
Distributed?
MW-40 Arsenic 50 10 100% Not Tested 5.71 25 25 Fractional
MW-40 Beryllium 4 10 100% Not Tested 1.39 2 2 Fractional
MW-40 Cadmium 5 10 100% Not Tested 1.39 2.5 2.5 Fractional
MW-40 Chromium 100 10 100% Not Tested 19.47 50 50 Fractional
MW-40 Cobalt 730 10 100% Not Tested 9.47 365 365 Fractional
MW-40 Copper 1300 10 100% Not Tested 9.47 650 650 Fractional
MW-40 Iron 11000 10 90% No 9 0.08187 41 5500 5500 Fractional
MW-40 Lead 15 10 100% Not Tested 2.04 7.5 7.5 Fractional
MW-40 Manganese 800 10 0% No -22 0.02966 206 400 400 Fractional
MW-40 Mercury 2 10 100% Not Tested 1.39 1 1.39 Poisson Prediction Limit
MW-40 Molybdenum 40 10 100% Not Tested 9.47 20 20 Fractional
MW-40 Nickel 100 10 100% Not Tested 16.25 50 50 Fractional
MW-40 Selenium 50 10 0% Yes 0.70593 0.02253 0.4983 Increasing 160.5 25.8639603 196 25 212.23 mean + 2SD 240.75 1.5 x mean
MW-40 Silver 100 10 100% Not Tested 9.47 50 50 Fractional
MW-40 Thallium 2 10 90% No -5 0.24312 0.603 1 1 Fractional
MW-40 Tin 17000 10 100% Not Tested 63.76 8500 8500 Fractional
MW-40 Uranium 30 10 0% Yes -0.34515 0.32869 0.1191 25.29 1.81625378 27.8 15 28.92 mean + 2SD
MW-40 Vanadium 60 10 100% Not Tested 12.94 30 30 Fractional
MW-40 Zinc 5000 10 80% No -17 0.01916 Decreasing 66.1 2500 2500.00 Fractional
MW-40 GrossAlpha 15 9 22% Yes -0.23944 0.53492 0.0573 1.3778 0.38005848 1.92 7.5 1.339 0.429 1.15 mean + 2SD (Cohen Adjustment)
MW-40 Acetone 700 10 100% Not Tested 16.25 350 350 Fractional
MW-40 Benzene 5 10 100% Not Tested 2.04 2.5 2.5 Fractional
MW-40 Methyl ethyl ketone 4000 10 100% Not Tested 16.25 2000 2000 Fractional
MW-40 Carbon tetrachloride 5 10 100% Not Tested 2.04 2.5 2.5 Fractional
MW-40 Chloroform 70 10 100% Not Tested 2.04 35 35 Fractional
MW-40 Chloromethane 30 10 100% Not Tested 2.04 15 15 Fractional
MW-40 Methylene chloride 5 10 100% Not Tested 2.04 2.5 2.5 Fractional
MW-40 Naphthalene 100 10 100% Not Tested 2.04 50 50 Fractional
MW-40 Tetrahydrofuran 46 10 100% Not Tested 2.04 23 23 Fractional
MW-40 Toluene 1000 10 100% Not Tested 2.04 500 500 Fractional
MW-40 Xylenes, Total 10000 10 100% Not Tested 2.04 5000 5000 Fractional
MW-40 Chloride (mg/L) 9 0% Yes -0.56085 0.11619 0.3146 41.433 3.88458492 47.1 49.20 mean + 2SD
MW-40 Fluoride (mg/L) 4 10 0% Yes 0.55728 0.09421 0.3106 0.6905 0.08394211 0.805 2 0.86 mean + 2SD
MW-40 Field pH (s.u.) 10 0% Yes 0.47601 0.16432 0.2266 6.762 0.24822928 7.06 7.26 mean + 2SD
MW-40 Sulfate (mg/L) 10 0% Yes 0.31499 0.37535 0.0992 2196 242.175327 2600 2680.35 mean + 2SD
MW-40 TDS (mg/L) 10 0% Yes -0.24454 0.49593 0.0598 3470 189.326291 3760 3848.65 mean + 2SD
Notes:
%ND = the percent of non-detected values in a data set.pCi/L = picocuries per liter.
µg/L = micrograms per liter.r = strength and direction of the linear relationship, where a negative value indicates decreasing trend.
GWCL = groundwater concentration limit.r2 = The measure of how well the trendline fits the data where r2=1 represents a perfect fit.
mg/L = milligrams per liter.SD or Std. Dev. = standard deviation.
N = number of data points in a data set.s.u. = standard units.
p = probability, where a value <0.05 is significant.
S = Mann-Kendall statistic indicating how strong the trend is and which direction the data are trending (i.e. A large positive S value indicates
a strong increasing trend, where a small negative value indicates a weaker decreasing trend).
GWQS = Ground Water Quality Standard (R317-6-2 UT Administrative Code).
HHV = Highest historical value.
MW-40 Heavy Metals (µg/L)
MW-40 Radiologics (pCi/L)
MW-40 Volatile Organic Compounds (µg/L)
MW-40 Other
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 3 of 3
TABLE 9
Estimation of Perched Groundwater Pore Velocities at
MW-38, MW-39, and MW-40
perched 1hydraulic 2approximate 2change in hydraulic 3pore
groundwater conductivity path length head gradient velocity
well (feet per day) (feet) (feet) (feet per foot) (feet per year)
MW-38 0.192 1280 20 0.0156 6.08
MW-39 0.049 1410 20 0.0142 1.42
MW-40 0.353 1400 20 0.0143 10.2
Notes:
1based on KGS analysis of automatically logged slug test data as presented in HGC (2018).
2as shown on water level contour map.
3assumes porosity of 18%.
Page 1 of 1

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Blanding, Utah
APPENDIX A
Box Plots
Appendix A: Box Plots

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
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Appendix A: Box Plots

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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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Appendix A: Box Plots

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White Mesa Uranium Mill, Blanding, Utah
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Appendix A: Box Plots

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White Mesa Uranium Mill, Blanding, Utah
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Appendix A: Box Plots

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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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White Mesa Uranium Mill, Blanding, Utah
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Appendix A: Box Plots

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
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Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Blanding, Utah
APPENDIX B
Histograms and the Shapiro-Wilk Test for Data Sets with 0%-50% Non-Detects
Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 16
>, u
C
(].)
::,
O"
(].) ....
LL
0
C'?
LO
N
0
N
LO ......
0 ......
LO
0
0
0
Nitrogen, Ammonia as N (mg/I) in MW-39
SW-W = 0.8815, p = 0.1359
-0.64 -0 .62 -0.60 -0.58 -0 .56 -0.54 -0.52 -0 .50 -0.48
C'?
>, u
C (].)
::, N
O"
(].) ....
LL
......
0
1.10
--~INTERA
Log Result
Nitrate+ Nitrite as N (mg/I) in MW-38
SW-W = 0.9129, p = 0.3014
1.12 1.14 1.16 1.18
Log Result
1.20
Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 2 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 3 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 4 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 5 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 6 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 7 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 8 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 9 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 10 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 11 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 12 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 13 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 14 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 15 of 16

Appendix B: Histograms and the Shapiro-Wilk Test for Data Sets with 0% - 50% Non-Detects

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 16 of 16

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Blanding, Utah
APPENDIX C
Time Series Plots for All Constituents Showing Linear Regressions for Normal and Log-Normal Distributions
(Non-Detected Values are Substituted with the Minimum Detection Limit)
Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 2 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 3 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 4 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 5 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 6 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 7 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 8 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 9 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 10 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 11 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 12 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 13 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 14 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 15 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 16 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 17 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 18 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 19 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 20 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 21 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 22 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 23 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 24 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 25 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 26 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 27 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 28 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 29 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 30 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 31 of 38

l)
l)
l)
Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 32 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 33 of 38

l)
l)
l)
Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 34 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 35 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 36 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 37 of 38

Appendix C: Time Series Plots for All Constituents Showing Linear Regressions for
Normal and Log-Normal Distributions (Non-Detected Values are Substituted with the
Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 38 of 38

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Blanding, Utah
APPENDIX D
Probability Plots for Constituents with 0-50% Non-Detected Values (Non-Detected Values are Substituted with the
Minimum Detection Limit)
Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 18
Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 2 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 3 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 4 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 5 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 6 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 7 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 8 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 9 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 10 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 11 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 12 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 13 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 14 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 15 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 16 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 17 of 18

Appendix D: Probability Plots for Constituents with 0-50% Non-Detected Values (Non-
Detected Values are Substituted with the Minimum Detection Limit)

Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 18 of 18

Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Blanding, Utah
APPENDIX E
Censored and Detected Values Only Probability Plots – Normally and Lognormally Distributed Data Sets
with 15% - 50% Non-Detected Values and
Summary of Descriptive Statistics and Trend Analysis for Censored Datasets
Appendix E1: Censored and Detected Values Only Probability Plots – Normally and
Lognormally Distributed Data Sets with 15% - 50% Non-Detected Values
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 1
R2 = 0.915
R2 = 0.955
APPENDIX E2: Summary of Descriptive Statistics and Trend Analysis for Censored Datasets
Wp Wp S p
MW-40 Gross Alpha minus Rn and U pCi/L detects only 7 0% 1.486 0.363 1.12 1.27 1.92 0.806 0.0936 yes 0.817 0.12 yes -3 0.386 no
MW-40 Gross Alpha minus Rn and U pCi/L ND = DL 9 22% 1.378 0.38 1 1.26 1.92 0.821 0.0622 yes 0.849 0.128 yes -7 0.306 no
MW-40 Gross Alpha minus Rn and U pCi/L ND = DL/2 9 22% 1.267 0.536 0.5 1.26 1.92 0.89 0.297 yes 0.832 0.0676 yes -7 0.306 no
MW-40 Gross Alpha minus Rn and U pCi/L ND = 0 9 22% 1.156 0.726 0 1.26 1.92 0.844 0.0896 yes N/A N/A N/A -7 0.306 no
MW-40 Gross Alpha minus Rn and U pCi/L Full, Cohen Adjust 9 22% 1.339 0.429
Notes:
µg/L = micrograms per liter
% ND = percent of non-detect values
DL = detection limit
N = number of valid data points
p = probability
S = Mann-Kendell test statistic
SD = standard deviation
W = Shapiro-Wilk test value
Normal?
Shaprio -Wilk Test
for Log Normality Log
Normal?
Mann-Kendall Trend
Test Significant
Trend?
Shapiro-Wilk Test
for NormalityWell Constituent Units Dataset Description N % ND Mean SD Min Median Max
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White Mesa Uranium Mill, Blanding, Utah
Page 1 of 1
Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Blanding, Utah
APPENDIX F
Data That Have Been Removed or Modified Prior to Statistical Analyses
Appendix F: Data That Have Been Removed or Modified Prior to Statistical Analyses
Field_Sample_
ID
Location_
ID
Date_
Sampled
Parameter_
Name
Report_
Result
Report_U
nits
Lab_
Qualifier
Sample_
Type Reason Removed
MW-38_07182019 MW-38 7/18/2019 Gross Alpha minus Rn and U 4.07 pCi/L GW Extreme Outlier
MW-39_07172019 MW-39 7/17/2019 Gross Alpha minus Rn and U 17.9 pCi/L GW Extreme Outlier
MW-40_07162019 MW-40 7/16/2019 Gross Alpha minus Rn and U 5.24 pCi/L GW Extreme Outlier
MW-40_05032018 MW-40 5/3/2018 Chloride 53.9 mg/L GW Extreme Outlier
MW-39_05032018 MW-39 5/3/2018 Copper 51.1 ug/L GW Extreme Outlier
MW-39_10292019 MW-39 10/29/2019 Fluoride 1.11 mg/L GW Extreme Outlier
MW-39_05032018 MW-39 5/3/2018 Iron 12900 ug/L GW Extreme Outlier
MW-39_10222018 MW-39 10/22/2018 Manganese 1970 ug/L GW Extreme Outlier
MW-39_05032018 MW-39 5/3/2018 Nitrate + Nitrite as N 0.182 mg/L GW Extreme Outlier
MW-39_07102020 MW-39 7/10/2020 pH 5.08 pH Units GW Extreme Outlier
MW-38_11062019 MW-38 11/6/2019 Potassium 41 mg/L GW Extreme Outlier, non-regulated constituent
MW-39_05032018 MW-39 5/3/2018 Zinc 293 ug/L GW Extreme Outlier
Notes:
µg/L = micrograms per liter
mg/L = milligrams per liter
pCi/L = picocuries per liter
U = result not detected above the laboratory reporting limit
Background Groundwater Quality Report for MW-38, MW-39, and MW-40
White Mesa Uranium Mill, Blanding, Utah
Page 1 of 1
Background Groundwater Quality Report for MW-38, MW-39, and MW-40 White Mesa Uranium Mill Blanding, Utah
APPENDIX G
Input and Output Files (Electronic Only)