DRC-2021-009762 - 0901a06880eeb134

DR-- 2024- CO q7(02._
Department of
Environmental Quality
Kimberly D. Shelley
Executive Director
DIVISION OF WASTE MANAGEMENT
AND RADIATION CONTROL
Doug Hansen
Director
MEMORANDUM
TO: File /THROUGH: Phil Goble, Manager PE 6 5.--4 --z r (
FROM: Tom Rushing, P.G.
DATE: May 18, 2021 j/2- 61/ 5- /2- (
SUBJECT: Energy Fuels Resources (USA) Inc., March 4, 2021 Background Groundwater
Quality Report for Monitoring Wells MW-38, MW-39, and MW-40 White Mesa
Uranium Mill
Summary:
This is to summarize the Utah Division of Radiation Control ("DRC") review of the Energy Fuels
Resources (USA) Inc. (EFRI) March 4, 2021 "Background Groundwater Quality Report for
Monitoring Wells MW-38, MW-39, and MW-40 White Mesa Uranium Mill" ("Background
Report"). The Report was prepared to comply with Utah Ground Water Discharge Permit No.
UGW370004 ("Permit") Part I.H.1.
Part I.H.1 of the Permit states, "Background Groundwater Quality Report for Wells MW-38, MW-
39, MW-40 - within30 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, 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
195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144850 • Salt Lake City, UT 84114-4850
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www deq utah.gov
Printed on 100% recycled paper
EFR MW-38, MW-39, and MW-40 Background Report
DWMRC Review Memo
Page 2
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."
A conference call was held on May 17, 2021 between DWMRC and EFRI to discuss the findings
of the Background Report review and GWCL's discussed in this memo, and to discuss whether
MW-38, MW-39 and MW-40 will be included in the Permit as Compliance Monitoring Wells or
General Monitoring Wells.
DWMRC recognizes that wells MW-38, MW-39, and MW-40 are currently cross gradient from
potential tailings cell discharge (per current groundwater monitoring head data and groundwater
contour mapping) and there is no indication of Mill caused groundwater impacts in the wells.
However, DWMRC explained that current Mill conditions may warrant a compliance well
designation for MW-38, MW-39, and MW-40 when considering the background concentrations
and the expansion of future tailings disposal further down the mesa. Specifically:
1. Several constituents in MW-38, MW-39 and MW-40 were noted to be in exceedance of
State Water Quality Standards (GWQS's). Beryllium, iron, manganese, thallium, and pH
were noted to be above GWQS's at MW-39 in addition to selenium at both MW-38 and
MW-40 and Nitrate + Nitrite (as N) at MW-38.
2. EFRI has applied for approval of new tailings cells 5A and 5B which are planned to be
constructed to the south of current cells 4A and 4B. Monitoring wells MW-38, MW-39
and MW-40 will be useful as downgradient/cross-gradient compliance wells for tailings
cells 5A and 5B when considering the southern extension. MW-38, MW-39 and MW-40
would be useful as an addition to the closer downgradient wells submitted for
installation/monitoring of per locations in the EFRI application to ensure that the eastern
cross gradient wells continue to conform to background data findings.
3. Per DWMRC review of the MW-38, MW-39 and MW-40 background data, only two
constituents are demonstrating significant increasing trends, TDS in monitoring well MW-
38 and selenium in monitoring well MW-40. The GWCL's for these constituents are
proposed to be set by methods acknowledging the increasing trends, 1.25 X background
EFR MW-38, MW-39, and MW-40 Background Report
DWMRC Review Memo
Page 3
and 1.5 X background, respectively. Per DWMRC findings since most of the Report
constituents for MW-38, MW-39 and MW-40 are not demonstrating increasing trends, and
since most GWCL's are based on fractions of the groundwater quality standard, it is not
anticipated that natural variation would cause exceedances of the proposed GWCL's and
that if an exceedance of the proposed GWCL's does occur then compliance actions per the
Permit will be warranted.
Per the May 17, 2021 conference call, EFRI was concerned that constituent GWCL's based on
Mean + 2cr may exceed the GWCL and cause unnecessary accelerated monitoring of those
constituents. EFRI was also concerned that natural conditions including dispersal of groundwater
from the former southern wildlife pond may cause reactions in the perched aquifer (oxidation of
minerals) causing exceedances of constituent GWCL's in the future. EFRI expressed that they
would like DWMRC to review the upcoming submission of a geochemical study which is being
submitted in response to ongoing investigation of out of compliance constituents at monitoring
well MW-24, which is anticipated to be expanded to a sitewide investigation, before making the
decision to designate MW-38, MW-39, and MW-40 as compliance monitoring wells.
Per the call, DWMRC explained that the decision of whether to include MW-38, MW-39 and
MW-40 as compliance monitoring wells or general monitoring wells would be delayed until
modification of the Permit later in the year. Any information EFRI would submit before then will
be considered by the Division. Final review discussion regarding the well designations will be
included in the Permit Modification Statement of Basis.
Ground Water Velocity Calculations:
The groundwater monitoring network for the White Mesa Uranium Mill is screened in the Burro
Canyon Formation. Per past studies and reviews the Burro Canyon Formation is highly variable
in conglomeratic deposition (fluvial), shows spatial variability in groundwater hydraulic and
geochemical parameters. The monitoring parameters are therefore set on an intrawell basis with
background concentrations of individual parameters being evaluated separately for each
monitoring well.
Permeability of the Burro Canyon Formation is generally low. No significant joints or fractures
within the formation have been documented in past studies and monitoring well installations. Any
observed joints or fractures were noted to have been cemented (calcific) with no open space or
impacts on hydraulic conductivity estimates.
Per the EFR June 6, 2014 Hydrogeology Report for the White Mesa Uranium Mill and a 1994
report prepared by Titan Environmental titled Hydrogeological Evaluation of White Mesa
Uranium Mill, "hydraulic conductivity of the Burro Canyon Formation ranges from 1.9 * 1O-7 to
1.6 * 10-3 cm/s, with a geometric mean of 1.01 * io-5 cm/s, based on the results of 12
pumping/recovery tests performed in monitoring wells and 30 packer tests performed in borings
prior to 1994. As discussed in Section 2, subsequent testing of wells by HGC yields a hydraulic
conductivity range of approximately 2 * 10-8 to aw cres."
EFR MW-38, MW-39, and MW-40 Background Report
DWMRC Review Memo
Page 4
It was noted in the Background Report that hydraulic conductivities and groundwater pore
velocities determined for MW-38, MW-39 and MW-40 are summarized on Table 9 of the
Background Report. In general, these estimates are consistent with sitewide velocities measured
in the perched groundwater beneath the site. More detailed information regarding the slug testing
procedures and results of hydraulic analysis are in the Hydro Geo Chem (HGC) June 12, 2018
well as built report. It is noted that the values are not directly transcribed between HGC 2018 and
the Background Report but are in the same range. The hydraulic estimates are based on well-
specific hydraulic conductivities, hydraulic gradient, and effective aquifer porosity. Hydraulic
gradient calculations are based on 4th Quarter 2020 water levels as shown in Figure 3 of the
Background Report.
The Background Report Section 3.5 Hydraulic Properties summarizes activities to estimate
groundwater pore velocity at monitoring wells MW-38, MW-39 and MW-40. The EFR
calculations are based on the geometric mean of "well-specific estimates of hydraulic
conductivities, hydraulic gradient, and effective porosity." Per Table 9 of the Background Report:
Table 1: A uifer Parameters Calculated for Monitorin Wells MW-38, MW-39, and MW- 0
Well Hydraulic
Conductivity K
(ft/day)
Hydraulic
Conductivity K
(cm/s)
Hydraulic
Gradient (ft/ft)
Groundwater Pore
Velocity (ft/yr)
MW-38" 0.0192 6.77E-05 0.0156 6.08
MW-39* 0.049 1.73E-05 0.0142 1.42
MW-40' 0.353 1.25E-04 0.0143 10.2
Per the Background Report -- DWMRC noted that these values are developed from the June 12, 2018 HGC As Built Report lug tests
though not directly comparable to measured results in the as built report.
Per review of the relevant well installation and hydraulic testing report prepared by Hydro Geo
Chem., listed below, it appears that the groundwater velocities were based on estimations of
hydraulic conductivity and specific storage calculated with the use of the Kansas Geological
Survey ("KGS") Model, and field slug testing measurements (falling head) at each monitoring
well. Per review of the slug test results tables for each of the applicable monitoring wells, it
appears that the measured values correspond to the values submitted with the background
monitoring report.
1. Hydro Geo Chem. Inc., June 12, 2018, Installation and Hydraulic Testing of Perched
Monitoring Wells MW-38, W-39 and MW-40 at the White Mesa Uranium Mill near
Blanding, Utah.
Per review of the Hydro Geo Chem. Inc. reports, it appears that data were collected and analyzed
according to appropriate slug test methods, however, per limitations of slug testing methods it is
noted that the calculated linear groundwater velocities are considered estimates only.
Per review of the drill logs and well completion diagrams for monitoring wells MW-38, MW-39,
and MW-40, the following information was noted:
EFR MW-38, MW-39, and MW-40 Background Report
DWMRC Review Memo
Page 5
Table 2: Well Com letion Data
Well No. Screen Interval (ft.) Static Water Level
(ft.)
Brushy Basin
Formation Contact
Depth (ft.)
MW-38 44.3 to 74.3 68.9 72.0
MW-39 62.5 to 102.5 64.2 97.0
MW-40 70.0 to 120.0 78.4 120.0
Per criteria listed in the Permit Part I.E., groundwater samples are to be collected at the following
frequencies.
• Semi-annual (2 times/year) where groundwater velocity is less than 10 feet/year, and,
• Quarterly (4 times/year) where groundwater velocity is equal to or greater than 10
feet/year.
Based on the calculated groundwater pore velocities discussed above (with an exception for MW-
40), the required monitoring frequencies for monitoring wells MW-38, MW-39, and MW-40 are
listed on table 3 below.
Table 3: Monitoring Fre uenc
Monitoring Well No. Monitoring Frequency
MW-38 Semi-Annual
MW-39 Semi Annual
MW-40 Semi Annual'
The groundwater pore velocity is above 10 feet/year for well MW-40, however, the reported value is 10.2
feet/year which does not warrant quarterly monitoring based on professional judgement and location of the
well cross-gradient from tailings disposal.
Class of Groundwater MW-38, MW-39, MW-40:
Per DRC review of the average TDS concentrations for monitoring wells MW-38, MW-39 and
MW-40, based on all data submitted for the applicable well, the groundwater class protection level
for the three study wells was Class III (total dissolved solids greater than 3,000 mg/L and less than
10,000 mg/L).
Table 4: Ground Water Class (UAC R317-6-3) at Monitoring Wells MW-35, MW-36, and MW-37
Well No. Number of
Samples
TDS Concentration Average Groundwater Class
Protection Level
(UAC R317-6-4)
MW-38 12 4,007 mg/L Class III
MW-39 10 4,216 mg/L Class III
MW-40 10 3,470 mg/L Class 111
EFR MW-38, MW-39, and MW-40 Background Report
DWMRC Review Memo
Page 6
Utah Administrative Code (UAC) R-317-6-4.6 concerning setting of protection levels based on
fractions of the ground water quality standards for Class III Groundwater are summarized on table
5 below:
Table 5 — Fraction of GWQS Method Class III Protection Levels
Groundwater
Class TDS Limit
Groundwater Protection Levels
Undetectable
Contaminant
(greatest of)
Detectable Contaminant
(greatest of)
III 1.25 * BG 0.5 * GWQS MDL 1 .5 *
BG
Mean +
2ct
0.5 *
GWQS
Per above and Section 3.3 of the Report revised groundwater compliance limits were calculated
and are presented in Table 8 of the Background Report. The proposed GWCL's are summarized
on the tables below. Concentrations). Most of the proposed GWCL's were calculated based on
fractions of the GWQS's (Ground Water Class Basis) as listed on the table below. In cases where
the GWCL's were calculated by alternative methods it was confirmed that such calculation was in
conformance with the Director Approved Statistical Process Flow Chart (Intera, 2007).
Some of the proposed GWCL's were adjusted by DWMRC and are included on the tables below
in a separate column.
Table 6 — Pro osed GWCL's for Monitorin Well MW-38 and DRC Ad ustments
Monitoring Well MW-38
Parameter Proposed GWCL GWQS Method DWMRC
Adjustment
Ammonia 12.5 mg/L 25 mg/L Fractional
Nitrate/Nitrite 16.04 mg/L 10 mg/L Mean + 2a
Arsenic 25 ug/L 50 ug/L Fractional
Beryllium 2 ug/L 4 ug/L Fractional
Cadmium 2.5 ug/L 5 ug/L Fractional
Chromium 50 ug/L 100 ug/L Fractional
Cobalt 365 ug/L 730 ug/L Fractional
Copper 650 ug/L 1,300 ug/L Fractional
Iron 5500 ug/L 11,000 ug/L Fractional
Lead 7.5 ug/L 15 ug/L Fractional
Manganese 400 ug/L 800 ug/L Fractional
Mercury 1.39 µg/L 2 ug/L Poisson
Prediction Limit
Molybdenum 20 ug/L 40 ug/L Fractional
Nickel 16.25 ug/L 10 ug/L Poisson
Prediction Limit
Selenium 178.74 ug/L 50 ug/L Mean + at
Silver 50 ug/L 100 ug/L Fractional
EFR MW-38, MW-39, and MW-40 Background Report
DWMRC Review Memo
Page 7
Monitoring Well MW-38
Parameter Proposed GWCL GWQS Method DWMRC
Adjustment
Thallium 1.39 Rg/L 2 pig/L Poisson
Prediction Limit
Tin 8,500 [A,g/L 17,000 n/L Fractional
Uranium 7.16 [ig/L 30 I.,tWL Mean + 2a
Vanadium 30 [A.g/L 601.,ig/L Fractional
Zinc 2,500 [ig/L 5,000 tig/L Fractional
Gross Alpha 7.5 pCi/L 15 pCi/L Fractional
Acetone 350 tig/L 700 lig/L Fractional
Benzene 2.5 [t,g/L 51.1g/L Fractional
Methyl Ethyl
Ketone
2,000 p,g/L 4,000 a g/L Fractional
Carbon
Tetrachloride
2.5 p,g/L 5 [ig/L Fractional
Chloroform 35 p.g/L 70 [tg/L Fractional
Chloromethane 15 vg/L 30 ttg/L Fractional
Methylene
Chloride
2.5 [A,g/L 5 tig/L Fractional
Naphthalene 501.1g/L 100 Ixg/L Fractional
Tetrahydrofuran 23 pig/L 46 [A.g/L Fractional
Toluene 500 tig/L 1,000 [ig/L Fractional
Xylenes, Total 5,000 n/L 10,000 ag/L Fractional
Chloride 48.7 mg/L Mean + 2a
Fluoride 0.98 mg/L 4 mg/L Mean + 2a
Field pH 7.6 S.U. Mean + 2a 6.5 — 8.5 S.U.
Sulfate 3126.75 mg/L HHV
TDS 5008.75 mg/L 1.25 X Mean
(1.25 X BG)
Table 7 — Pro osed GWCL's for Monitorin Well MW-39 and DRC Adiustments _
Monitoring Well MW-39
Parameter Proposed GWCL GWQS Method DWMRC
Adjustment
Ammonia 0.33 mg/L 25 mg/L Mean + 2a
Nitrate/Nitrite 5 mg/L 10 mg/L Fractional
Arsenic 25 p,g/L 50 ilg/L Fractional
Beryllium 5.97 lig/L 4 p,g/L Mean + 2a
Cadmium 3.01 !AWL 5 aWL Mean + 2a
Chromium 50 [A,g/L 100 IA,g/L Fractional
Cobalt 79.17 ag/L 730 tig/L Mean + 2a
Copper 35.55 ag/L 1,300 ag/L Mean + 2a
EFR MW-38, MW-39, and MW-40 Background Report
DWMRC Review Memo
Page 8
Monitoring Well MW-39
Parameter Proposed GWCL GWQS Method DWMRC
Adjustment
Iron 15506.23 jig/L 11,000 jig/L Mean + 2ot
Lead 7.5 ug/L 15_jug/L Fractional
Manganese 2320 jig/L 800 jtg/L HHV
Mercury 1.39 ug/L 2 jtg/L Poisson
Prediction Limit
Molybdenum 20 jigiL 40 jig/L Fractional
Nickel 39.25 ji,g/L 100 jig/L Mean + 2ta
Selenium 25 ug/L 50 ttg/L Mean + 2a,
Silver 50 ug/L 100 ug/L Fractional
Thallium 3.82 jtg/L 2 ug/L Mean + 2ct
Tin 8,500 jig/L 17,000 jtg/L Fractional
Uranium 13.95 jig/L 30 ug/L Mean + 2ct
Vanadium 30 ug/L 60 ug/L Fractional
Zinc 259 ug/L 5,000jig/L Mean + 2ct
Gross Alpha 5.47 pCi/L 15 pCi/L Mean + 2ct
Acetone 350 ug/L 700 jtg/L Fractional
Benzene 2.5 ug/L 5 [tg/L Fractional
Methyl Ethyl
Ketone
2,000 !AWL 4,000 ug/L Fractional
Carbon
Tetrachloride
2.5 ug/L 5 jtg/L Fractional
Chloroform 35 jtg/L 70 pig/L Fractional
Chloromethane 15 lug/L 30 jig/L Fractional
Methylene
Chloride
2.5 jtg/L 5 !AWL Fractional
Naphthalene 50 ug/L 100 ug/L Fractional
Tetrahydrofuran 23 ug/L 46 jtg/L Fractional
Toluene 500 jtg/L 1,000 jtg/L Fractional
Xylenes, Total 5,000jig/L 10,000 ug/L Fractional
Chloride 43.68 mg/L Mean + at
Fluoride 0.82 mg/L 4 mg/L Mean + 2ot
Field pH 4.51 S.0 Mean + 2ct 4.51 — 8.5 S.U.
Sulfate 3522.07 mg/L ' Mean + 2ct
TDS 4,713.48 mg/L Mean + 4ct 1.25 X BG =
5270 mg/L
EFR MW-38, MW-39, and MW-40 Background Report
DWMRC Review Memo
Page 9
Table 8 — Pro osed GWCL's for Monitorin Well MW-40 and DRC Ad ustments
Monitoring Well MW-40
Parameter Proposed GWCL GWQS Method DWMRC
Adjustment
Ammonia 12.5 mg/L 25 mg/L Fractional
Nitrate/Nitrite 3.41 mg/L 10 mg/L Mean + 2a
Arsenic 25 p,g/L 50 RWL Fractional
Beryllium 2 Rg/L 4 [ig/L Fractional
Cadmium 2.5 lig/L 5 p,g/L Fractional
Chromium 50 pt, g/L 100 !AWL Fractional
Cobalt 365 I.A.g/L 730 lAg/L Fractional
Copper 650 vg/L 1,300 pig/L Fractional
Iron 5,500 [AWL 11,000 [tg/L Fractional
Lead 7.511 g/L 15 tig/L Fractional
Manganese 400 vg/L 80011g/L Fractional
Mercury 1.39 lig/L 2 p,g/L Poisson
Prediction Limit
Molybdenum 20 [tg/L 40 ttg/L Fractional
Nickel 50 tig/L 100 [Ig/L Fractional
Selenium 240.75 tig/L 501,A.g/L 1.5 X Mean
(1.5 X BG)
Silver 50 vg/L 100 lAg/L Fractional
Thallium 1 lig/L 2 kg/L Fractional
Tin 8,500 ttg/L 17,000 ttg/L Fractional
Uranium 28.92 lig/L 30 fig/L Mean + 2a
Vanadium 30 ttg/L 60 p.g/L Fractional
Zinc 2500 lig/L 5,000n/L Fractional
Gross Alpha 1.15 pCi/L 15 pCi/L Mean + 211
Acetone 350 [tg/L 700 ilg/L Fractional
Benzene 2.511g/L 51,tg/L Fractional
Methyl Ethyl
Ketone
2,000n/L 4,000 vg/L Fractional
Carbon
Tetrachloride
2.5 [A,g/L 5 [A.g/L Fractional
Chloroform 35 Iiig/L 70 lig/L Fractional
Chloromethane 15 1A,g/L 30 lig/L Fractional
Methylene
Chloride
2.5 p.g/L 5 [A,g/L Fractional
Naphthalene 50 vg/L 100 lAg/L Fractional
Tetrahydrofuran 23 p.g/L 46 [tg/L Fractional
Toluene 500 Rg/L 1,000 p,g/L Fractional
Xylenes, Total 5,000 [A,g/L 10,000 vg/L Fractional
Chloride 49.20 mg/L Mean + 2a
EFR MW-38, MW-39, and MW-40 Background Report
DWMRC Review Memo
Page 10
Monitoring Well MW-40
Parameter Proposed GWCL GWQS Method DWMRC
Adjustment
Fluoride 0.86 mg/L 4 mg/L Mean + 2a
Field pH 7.26 S.U. Mean + 2a 6.5 — 8.5 S.U.
Sulfate 2680.35 mg/L Mean + 2a
TDS 3848.65 mg/L Mean + 2a 1.25 x Bckgnd =
4337.5 mg/L
Conclusions:
Based on review as discussed above, Groundwater Compliance Limits for groundwater
monitoring wells MW-38, MW-39 and MW-40 as summarized on the tables above, including
adjustments by DWMRC are appropriate and in conformance with the Permit and State rules and
regulations. It is noted that decisions regarding the designation of the wells as compliance or
general will be included with a future Permit modification and future discussion in the Permit
Statement of Basis. Monitoring frequencies will be included in the Permit as discussed above.
References
Hydro Geo Chem, Inc. June 12, 2018. Installation and Hydraulic Testing of Perched
Monitoring Wells MW-38, MW-39 and MW-40 White Mesa Uranium Mill Near Blanding,
Utah.
Hydro Geo Chem, Inc. July 10, 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.
INTERA. October 2007. Revised Background Groundwater Quality Report: Existing
Wells for Denison Mines (USA) Corp.'s White Mesa Mill Site, San Juan County, Utah.
INTERA. March 4, 2021. Background Groundwater Quality Report for Monitoring Wells
MW-38, MW-39, and MW-40 White Mesa Uranium Mill.
United States Environmental Protection Agency, March 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.
Utah Division of Radiation Control, December 1, 2004, Statement of Basis for Ground
Water Discharge Permit No. UGW450005, White Mesa Uranium Mill