DRC-2024-004047

195 North 1950 West • Salt Lake City, UT
Mailing Address: P.O. Box 144880 • Salt Lake City, UT 84114-4880
Telephone [phone] • Fax [phone] • T.D.D. [phone]
www.deq.utah.gov
Printed on 100% recycled paper
State of Utah

SPENCER J. COX
Governor

DEIDRE HENDERSON
Lieutenant Governor
Department of
Environmental Quality

Kimberly D. Shelley
Executive Director

DIVISION OF WASTE MANAGEMENT
AND RADIATION CONTROL

Douglas J. Hansen
Director

MEMORANDUM

TO: File

THROUGH: Phil Goble, Manager

FROM: Christopher Leahy, P.G.

DATE: January 16, 2024

SUBJECT: Review of the Energy Fuels Resources (USA) Inc. 3rd Quarter 2023 Groundwater
Monitoring Report for the White Mesa Uranium Mill

Review Summary:

The Utah Division of Waste Management and Radiation Control (“Division”) has reviewed the
following documents submitted by Energy Fuels Resources (USA) Inc. (“EFR”):

1. EFR, November 7, 2023, Transmittal of 3rd Quarter 2023 Groundwater Monitoring
Report Groundwater Quality Discharge Permit UGW370004 White Mesa Uranium
Mill. (Received by the Division on November 13, 2023)
2. EFR, October 25, 2023, State of Utah Ground Water Discharge Permit No.
UGW370004 White Mesa Uranium Mill – Notice Pursuant to Part I.G.1(a) (Received
by the Division on November 1, 2023)

The review was conducted to ensure compliance with all applicable parts of Utah Groundwater
Discharge Permit No. UGW370004 (“Permit”) issued for the White Mesa Uranium Mill located in
Blanding, Utah (Mill).

Significant Findings of the 3rd Quarter 2023 Report and Related Actions at the White Mesa
Uranium Mill:

When a monitoring well has a pollutant that exceeds a Ground Water Compliance Limit (GWCL)
set forth in Table 2 of the Permit, it is in Probable Out-of-Compliance (POOC) status. According
to the Permit, EFR is then required to immediately initiate accelerated sampling of that pollutant
EFR 3rd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 2

(see the Permit, Part I.G.1). No new compliance parameters went into accelerated monitoring
frequency POOC based on sampling during the 3rd Quarter 2023.

When monitoring wells have parameters that have exceeded the GWCL two or more consecutive
times they are in Out-of-Compliance (OOC) status (see the Permit, Part I.G.2). No new
compliance parameters went into OOC status based on their first consecutive non-exceedances
occurring during the quarter and/or previous quarter:

In the event a constituent is in OOC status, EFR is required to prepare and submit within 30
calendar days to the Director a plan and time schedule for assessment of the sources, extent and
potential dispersion of the contamination, and an evaluation of potential remedial action to restore
and maintain groundwater quality to ensure that Permit limits will not be exceeded at the
compliance monitoring point and that DMT or BAT will be re-established, in accordance with
Part I.G.4(c) of the Permit.

Table 1 and Table 2 below list monitoring wells with parameters currently in OOC or POOC
status as of the 3rd Quarter of 2023. The following wells therefore are required to be sampled
under the accelerated monitoring requirements. EFR is required to notify the DWMRC on a
quarterly basis regarding wells and parameters which went into accelerated monitoring during the
period [Part I.G.1(a), Accelerated Monitoring Status Reports (AMSR)].

Table 1 - Wells Monitored Quarterly Accelerated to Monthly Monitoring
Well Class *Position Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-11 Class II water

D-3
Chloride
Sulfate
Total Dissolved Solids
Manganese
Nitrate + Nitrite (as N)
Selenium
3rd Quarter 2019
3rd Quarter 2019
3rd Quarter 2020
3rd Quarter 2021
1st Quarter 2022
4th Quarter 2022
November 2019
November 2019
November 2020
November 2021
June 2022
March 2023
MW-25 Class III water D3 Chloride 4th Quarter 2022 March 2023
MW-26(a) Class III water

C-2
Nitrate + Nitrite (as N)
Chloroform
Chloride
February 2010
February 2010
February 2010
May 2010
May 2010
May 2010
MW-30 Class II water

D-2
Nitrate + Nitrite (as N)
Chloride
Uranium
Selenium
Field pH
February 2010
1st Quarter 2011
1st Quarter 2021
1st Quarter 2019
4th Quarter 2022
May 2010
May 2011
2nd Quarter 2021
May 2019
March 2023
MW-31 Class III water

D-2
Nitrate + Nitrite (as N)
Chloride
Total Dissolved Solids
Sulfate
Uranium
1st Quarter 2010
1st Quarter 2011
3rd Quarter 2019
3rd Quarter 2019
2nd Quarter 2020
May 2010
May 2011
November 2019
November 2019
August 2020
EFR 3rd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 3

D = Down-gradient; U = Up-gradient; C = Cross-gradient; 1,2,3,4A, 4B = Cell #
a = Monitoring well MW-26 is a pumping well for the Chloroform investigation

Table 2 - Wells Monitored Semi-annually Accelerated to Quarterly Monitoring
Well Class *Position Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-03A Class III water D-4B Selenium 2nd Quarter 2023 3rd Quarter 2023
MW-05 Class II water D-3 Uranium 2nd Quarter 2023 3rd Quarter 2023
MW-17 Class III water D-4A Chloride 4th Quarter 2022 2nd Quarter 2023
MW-24 Class III water D-1 Beryllium
Cadmium
Thallium
Field pH
Fluoride
Nickel
Manganese
Sulfate
Gross Alpha
Total Dissolved Solids
1st Quarter 2017
2nd Quarter 2018
2nd Quarter 2018
2nd Quarter 2018
1st Quarter 2018
1st Quarter 2018
1st Quarter 2019
1st Quarter 2020
1st Quarter 2020
2nd Quarter 2021
1st Quarter 2018
3rd Quarter 2018
3rd Quarter 2018
3rd Quarter 2018
3rd Quarter 2019
3rd Quarter 2019
1st Quarter 2020
3rd Quarter 2020
3rd Quarter 2021
3rd Quarter 2021
MW-27 Class III water U-1 Nitrate + Nitrite (as N)
Fluoride
2nd Quarter 2010
2nd Quarter 2022
3rd Quarter 2010
3rd Quarter 2022
MW-28 Class III water

D-1
Chloride
Uranium
Selenium
Nitrate + Nitrite (as N)
Total Dissolved Solids
2nd Quarter 2010
2nd Quarter 2014
2nd Quarter 2019
1st Quarter 2019
2nd Quarter 2023
3rd Quarter 2010
2nd Quarter 2014
3rd Quarter 2019
3rd Quarter 2020
3rd Quarter 2023
MW-29 Class III water D-2 Uranium 1st Quarter 2020 3rd Quarter 2021
MW-32 Class III water C-2 Chloride 2nd Quarter 2014 4th Quarter 2014
MW-37 Class III water D-4B Field pH 4th Quarter 2022 2nd Quarter 2023
* D = Down-gradient; U = Up-gradient; C = Cross-gradient; 1, 2, 3, 4A, 4B = Cell #

Each well with a parameter in accelerated status is described in detail below:

EFR 3rd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 4

Wells Monitored Quarterly - Accelerated to Monthly Monitoring

Well Water
Class
Location Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-11 Class II Downgradient
of Cell 3
Chloride
Sulfate
Total Dissolved Solids
Manganese
Nitrate + Nitrite (as N)
Selenium
3rd Quarter 2019
3rd Quarter 2019
3rd Quarter 2020
3rd Quarter 2021
1st Quarter 2022
4th Quarter 2022
November 2019
November 2019
November 2020
November 2021
June 2022
March 2023

Chloride and Nitrate + Nitrite (as N) - MW-11 is downgradient of the Nitrate plume and actions
currently being implemented from an approved CAP for Nitrate + nitrite are expected to address
chloride also. A 30-day plan and time schedule (P&TS) for assessment to address consecutive
exceedances is not necessary. Additional actions are not required at this time and concentrations
of these constituents in groundwater will be monitored closely.

Sulfate - Under the current GWDP, the first consecutive exceedances of the 1,309 mg/L GWCL
occurred during the accelerated monthly July and August 2021 sample events. A Source
Assessment Report (SAR) was approved by DWMRC on July 27, 2022, which proposed the
GWCL be modified to 1,493.6 mg/L. The new GWCL will become effective on the next revision
of the GWDP. In the 3rd Quarter 2023, Sulfate exceeded the current 1,309 mg/L GWCL during
the July and September monthly sample events (1,370 mg/L and 1,330 mg/L respectively).

Total Dissolved Solids (TDS) – TDS exceeded the GWCL of 2,528 mg/L during the 3rd Quarter
2020 sampling event and on three occasions during monthly sampling after, however, never on
consecutive occasions. At the conclusion of the 2nd quarter 2023, TDS had not exceeded the
GWCL for the last 8 monthly sample events. A request for removal of TDS from accelerated
sampling was approved by the Division in a letter dated August 22, 2023. TDS did not exceed the
GWCL during the two monthly sampling events performed in the 3rd Quarter 2023 (July and
August) and was returned to quarterly baseline sampling thereafter.

Manganese – Under the current GWDP, consecutive exceedances of the conservative 237 ug/L
GWCL for Manganese first occurred during the 3rd and 4th Quarter 2021 sampling events. A SAR
was approved by DWMRC on July 27, 2022 which proposed the GWCL be modified to 376 ug/L.
The new GWCL will become effective on the next revision of the GWDP. Including the 3rd
Quarter 2023, 9 of the last 14 accelerated monthly sample results have been below the current
GWCL.

Selenium – Consecutive exceedances of the current 12.5 ug/L GWCL for Selenium first occurred
during the 3rd Quarter and 4th Quarter 2022 sampling events. Accelerated monthly sampling
began in February 2023. A SAR was approved by DWMRC on November 6, 2023 which
proposed the GWCL be modified to 20.49 ug/L. The new GWCL will become effective on the
next revision of the GWDP.

EFR 3rd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 5

Well Water
Class
Location Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-25 Class III
water
Downgradient
of Cell 3 Chloride 4th Quarter 2022 March 2023

Chloride – Since the onset for sampling Chloride in groundwater at MW-25 in 2005, the
concentration has remained from approximately 30-35 mg/L. Single exceedances of the 35 mg/L
GWCL occurred during the 3rd Quarter 2015 sampling event then did not occur until the
4th Quarter 2022 sampling event when the concentration was 35.8 mg/L. Accelerated monthly
sampling began in the 1st Quarter 2023. Since then, Chloride exceeded the GWCL in 3 of the 9
monthly sampling events and on consecutive occasions in the June and July 2023 sample events at
concentrations just over the GWCL. An approved CAP addressing nitrate + nitrite contamination
in groundwater is expected to address chloride concentrations at nearby wells also. The actions
specified in the CAP are currently being implemented, therefore a P&TS for assessment to
address consecutive exceedances is not necessary.

Well Water
Class
*Position Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-26 Class III
water
Cross
Gradient of
Cell 2
Nitrate + Nitrite (as N)
Chloroform
Chloride
February 2010
February 2010
February 2010
May 2010
May 2010
May 2010

Note: MW-26 is used as a pumping well for the ongoing chloroform capture program and is
expected to yield increased concentrations of chloroform in groundwater. MW-26 is also located
within the nitrate plume which also contains elevated concentrations of chloride in groundwater.
CAPs have been approved by DWMRC addressing chloroform in 2011 and Nitrate +
Nitrite/Chloride in 2012. Activities associated with the CAPs are on-going and consecutive
exceedances of the GWCLs for these constituents is expected to occur. A P&TS for assessment of
consecutive exceedances is not necessary.

EFR 3rd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 6

Well Water
Class
*Position Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-30 Class II
water
Downgradient
of Cell 2
Nitrate + Nitrite (as N)
Chloride
Uranium
Selenium
Field pH
February 2010
1st Quarter 2011
1st Quarter 2021
1st Quarter 2019
4th Quarter 2022
May 2010
May 2011
2nd Quarter 2021
May 2019
March 2023

Nitrate + Nitrite (as N) and Chloride – MW-30 is downgradient from and within the Nitrate
plume and actions currently being implemented from an approved CAP for Nitrate + nitrite are
expected to address chloride also. A P&TS for assessment to address consecutive exceedances is
not necessary, concentrations of these constituents in groundwater will be monitored closely.

Uranium and Selenium - Concentrations of both of these constituents in groundwater has
increased gradually at similar rates since the inception of MW-30 in 2005. Under the current
GWDP, consecutive exceedances of the 9.82 ug/L GWCL for Uranium occurred in 2021 and the
47.2 ug/L GWCL for selenium, established during the 2018 GWDP revision, was exceeded on
consecutive occasions in 2019. A SAR was approved by DWMRC on April 5, 2022, which
proposed modifications of the GWCLs for Uranium to 13.11 ug/L and for Selenium to 72.52 ug/L.
The new GWCL will become effective in the next revision of the GWDP. Uranium exceeded the
GWCL in 2 of the 3 accelerated monthly sampling events in the 3rd Quarter 2023 (10.3 ug/L, 11.4
ug/L). Selenium exceeded the GWCL in all of the accelerated monthly sampling events in the 3rd
Quarter 2023 (70.7 ug/L, 70.8 ug/L, 73.0 ug/L).

Field pH – MW-30 was sampled for Field pH since 2005 and monthly since 2007. The first
exceedance of the GWCL range occurred in June 2011. Exceedances, including consecutive
occurred during monthly sampling from 2011-2018 and the GWCL range was modified to 6.47-
8.5 in the 2018 GWDP revision. Since the 2018 permit revision, only a few single exceedances of
the GWCL range have occurred. Field pH was within the GWCL range during all three of the 3rd
Quarter 2023 accelerated monthly sampling events and has been within the GWCL range during
the last 10 sample events. A request to return to quarterly baseline monitoring frequency was
approved by DWMRC on November 6, 2023.

EFR 3rd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 7

Well Water
Class
*Position Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-31 Class III
water
Downgradient
of Cell 2
Nitrate + Nitrite (as N)
Chloride
Total Dissolved Solids
Sulfate
Uranium
1st Quarter 2010
1st Quarter 2011
3rd Quarter 2019
3rd Quarter 2019
2nd Quarter 2020
May 2010
May 2011
November 2019
November 2019
August 2020

Nitrate + Nitrite (as N) and Chloride – MW-31 is downgradient from and within the
Nitrate/Chloride plume and actions currently being implemented from an approved CAP for
Nitrate + nitrite are expected to address chloride also. A P&TS for assessment to address
consecutive exceedances is not necessary, concentrations of these constituents in groundwater will
continue to be monitored closely.

Total Dissolved Solids (TDS) and Sulfate – Consecutive exceedances under the current GWCLs
for TDS (2,132 mg/L) and Sulfate (993 mg/L), established during the 2019 GWDP revision,
occurred in the 3rd and 4th Quarter 2019 sampling events for both constituents. A SAR was
approved by DWMRC on August 6, 2020, which proposed modifications of the GWCL for TDS
to 2,664 mg/L and Sulfate to 1,170.5 mg/L. The new GWCLs will become effective in the next
revision of the GWDP. Both constituents have experienced increases in concentrations in MW-31
since 2005, however, per DWMRC review, from 2021 until the 3rd Quarter 2023, a linear trend
analysis shows a flattening trend for TDS and Sulfate. TDS and Sulfate exceeded their current
GWCLs during all three of the 3rd Quarter 2023 monthly accelerated sampling events.

Uranium - The current GWCL for Uranium of 15 ug/L was established during the 2019 GWDP
revision. Consecutive exceedances of the current GWCL occurred in the 2nd and 3rd Quarter 2020
sampling events and accelerated monthly sampling began in August 2020. A SAR was approved
by DWMRC on July 7, 2021, which proposed modifications of the of the GWCL to 29.03 ug/L.
The new GWCL will become effective in the next revision of the GWDP. Uranium exceeded the
GWCL during all three of the 3rd Quarter 2023 monthly accelerated sampling events at
concentrations of 23.4, 25.8, and 27.1 ug/L.

EFR 3rd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 8

Wells Monitored Semi-annually Accelerated to Quarterly Monitoring

Well Water
Class
Location Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-03A Class III Downgradient
of Cell 4B
Selenium 2nd Quarter 2023 4th Quarter 2023

Selenium – Selenium exceeded the current GWCL of 109.58 ug/L in the 1st Semi-annual
sampling event of 2023 in April, testing at 112 ug/L. Accelerated quarterly sampling was initiated
in the 3rd Quarter 2023 sampling event and a second consecutive exceedance was recorded. A
P&TS for assessment was submitted and approved by DWMRC on December 5, 2023. A SAR is
now required to be submitted 90 days from December 5th. Per DWMRC review, a linear trend
analysis of Selenium concentration in groundwater since 2005 appears to show a slight upward
trend, however the concentration has been variable over that time, fluctuating between 70 ug/L
and 110 ug/L during the majority of sample events.

Well Water
Class
Location Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-05 Class II Downgradient
of Cell 3
Uranium 2nd Quarter 2023 4th Quarter 2023

Uranium – Under the current GWDP, Uranium first exceeded the GWCL of 7.5 ug/L in the 1st
Semi-annual sampling event of 2023 in April. Accelerated quarterly sampling was initiated for
the 3rd Quarter 2023 sampling event and results were below the GWCL. Per DWMRC review,
since 2005, the Uranium concentration in groundwater at MW-05 has been below the GWCL the
majority of the sample events (47 out of 56).

Well Water
Class
Location Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-17 Class III
water
Downgradient
of 4A
Chloride 4th Quarter 2022 2nd Quarter 2023

Chloride – Chloride exceeded the 46.8 mg/L GWCL during the 2nd Semi-Annual sampling event
of 2022 in October, testing at 54.0 mg/L. This is the first and only exceedance since sampling
was initiated in 2005. Accelerated quarterly sampling was initiated during the 1st Quarter 2023
and results did not exceed the GWCL. Chloride did not exceed the GWCL during the subsequent
2nd and 3rd Quarter 2023 sampling events. Per DWMRC review, since 2007, the Chloride
concentration in groundwater at MW-17 has been consistently between 30 mg/L and 40 mg/L
with the only exceedance being during the 4th Quarter 2022 sample event.

EFR 3rd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 9

Well Water
Class
Location Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-24 Class III
water
Downgradient
of Cell 1
Beryllium
Cadmium
Thallium
Field pH
Fluoride
Nickel
Manganese
Sulfate
Gross Alpha
Total Dissolved Solids
4th Quarter 2017
2nd Quarter 2018
2nd Quarter 2018
2nd Quarter 2018
3rd Quarter 2018
3rd Quarter 2018
3rd Quarter 2019
1st Quarter 2020
1st Quarter 2020
2nd Quarter 2021
1st Quarter 2018
3rd Quarter 2018
3rd Quarter 2018
3rd Quarter 2018
3rd Quarter 2019
3rd Quarter 2019
1st Quarter 2020
3rd Quarter 2020
3rd Quarter 2021
3rd Quarter 2021

Note: After multiple constituents reached OOC status, a SAR was approved by DWMRC in 2019
to study groundwater trends near MW-24. The source assessment is nearing completion as Phase
2 included installation of a downgradient/co-located well (MW-41B) in April 2023. An additional
P&TS for consecutive exceedances is not required. Exceedances will continue to be tracked until
conclusion of the source investigation. Groundwater sampling at co-located well MW-41B was
initiated for the 3rd Quarter 2023 sampling event.

Gross Alpha – Gross Alpha first exceeded the 7.5 pCi/L GWCL during the 2nd Semi-Annual
sampling event of 2020 in October. Accelerated quarterly sampling was initiated during the 1st
Quarter 2021 and no exceedances have occurred in the 13 sample events since.

Well Water
Class
Location Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-27 Class III
water
Upgradient of
Cell 1
Nitrate + Nitrite (as N)
Fluoride
2nd Quarter 2010
2nd Quarter 2022
3rd Quarter 2010
3rd Quarter 2022

Nitrate + Nitrite (as N) - MW-27 is downgradient/cross-gradient from the Nitrate plume and a
CAP addressing Nitrate + Nitrite in groundwater was approved in 2012. Activities associated
with the CAP are on-going and a P&TS for assessment of consecutive exceedances is not required
for Nitrate + Nitrite and Chloride. In the previous 5 quarterly sampling events including the 3rd
Quarter 2023, Nitrate + Nitrite (as N) has been below the GWCL of 5.6 mg/L.

Fluoride –Since 2010, Fluoride only exceeded the 0.85 mg/L GWCL one time during the 1st
Semi-Annual sampling event of 2022. Accelerated quarterly sampling was initiated during the 3rd
Quarter 2022. No exceedances have occurred since and concentrations have been decreasing
since the 4th Quarter 2022.

EFR 3rd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 10

Well Water
Class
Location Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-28 Class III
water
Downgradient
of Cell 1
Chloride
Uranium
Selenium
Nitrate + Nitrite (as N)
2nd Quarter 2010
2nd Quarter 2014
2nd Quarter 2019
1st Quarter 2019
3rd Quarter 2010
2nd Quarter 2014
3rd Quarter 2019
3rd Quarter 2020

Chloride and Nitrate + Nitrite (as N) – It appears that MW-28 is impacted by the western
margin of the Nitrate and Chloride plume and a CAP addressing Nitrate + Nitrite and Chloride in
groundwater was approved in 2012. Activities associated with the CAP are on-going and a P&TS
for assessment of consecutive exceedances is not required for Nitrate + Nitrite and Chloride. Per
DWMRC review, after increases in concentrations of both constituents since sampling of MW-28
began in 2005, Nitrate + Nitrite concentration from 2022-2023 has remained near the GWCL of 5
mg/L and Chloride concentration has remained near 150 mg/L.

Uranium and Selenium - Consecutive exceedances of the GWCLs for Uranium (4.9 ug/L) and
Selenium (11.1 ug/L) have occurred and a SAR was approved by DWMRC on January 21, 2021.
The SAR proposed modifications of the GWCLs for Uranium to 12.29 ug/L and for Selenium to
17.9 ug/L. The new GWCL will become effective in the next revision of the GWDP. Per
DWMRC review, concentrations of Uranium and Selenium in groundwater at MW-28 have
increased since 2017 but appear to show a flattening trend recently. Uranium exceeded the
GWCL during the 3rd Quarter 2023 sample event (11.2 ug/L). Selenium exceeded the GWCL
during the 3rd Quarter 2023 sample event (23.5 ug/L). Concentrations of Uranium and Selenium
in groundwater at MW-28 will continue to be monitored closely.

Well Water
Class
Location Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-29 Class III
water
Downgradient
of Cell 2 Uranium 4th Quarter 2020 2nd Quarter 2021

Uranium – The first exceedance of the current 15 ug/L GWCL was during the 2nd semi-annual
sampling event of 2020. Accelerated quarterly sampling and a consecutive exceedance occurred
in the 1st Quarter of 2021. A P&TS was submitted and a SAR was approved by DWMRC on
January 18, 2022. A modified GWCL of 20.2 ug/L will become effective in the next revision of
the GWDP. Per DWMRC review, Uranium concentrations in MW-29 from 2021-2023 have
remained steady and near the GWCL of 15 ug/L. Uranium did not exceed the GWCL in the 3rd
Quarter 2023 sampling event (14.1 ug/L).

EFR 3rd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 11

Well Water
Class
Location Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-32 Class III
water
Cross-
Gradient of
Cell 2
Chloride 2nd Quarter 2014 4th Quarter 2014

Chloride – MW-32 (also known as TW4-17) has been sampled for Chloride since 2005. The
GWCL has been established as 35.39 mg/L. Per DWMRC review, a linear trend analysis of
Chloride in MW-32 since 2005 appears to show a slight increasing trend, however, the
concentration in groundwater has generally remained from 30-40 mg/L with a handful of
exceptions over that same time. MW-32 is nearby the Nitrate plume and a CAP addressing
Nitrate + Nitrite and Chloride in groundwater was approved in 2012. Activities associated with
the CAP are on-going and a P&TS for assessment of consecutive exceedances is not required for
Chloride. Chloride exceeded the GWCL in the 3rd Quarter 2023 sampling event (38.4 mg/L).

Well Water
Class
Location Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-37 Class III
water
Downgradient
of Cell 4B
Field pH 4th Quarter 2022 2nd Quarter 2023

Field pH – During quarterly sampling from 2011 – 2017, Field pH exceeded the current GWCL
limits of 6.61 - 8.5 in 8 of the 26 sampling events including consecutive exceedances in 2016-
2017. Under the current GWDP, semi-annual sampling was performed from 2018 until an
exceedance occurred during the 2nd Semi-Annual sampling event of 2022 in November (pH =
6.60). A second consecutive exceedance of the GWCL limits occurred during accelerated
quarterly sampling initiated during the 1st Quarter 2023 (pH = 6.55) and Field pH at MW-37 went
into OOC status. A P&TS was submitted, and a SAR was approved by DWMRC on November 6,
2023. Per the SAR, the Field pH GWCL limits were modified to 6.05-8.5, based on the lowest
historical value, and will become effective in the next revision of the GWDP. Per DWMRC
review, a linear trend analysis since 2016 appears to show Field pH with an increasing trend
towards neutral. Field pH tested at 7.02 during the 3rd Quarter 2023 sample event.

EFR 3rd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 12

DWMRC Review Checklist:

1. Monitoring Wells Purged for Two Casing Volumes Before Sample Collection:

As stated in Section 6.2.7 of the EFR Quality Assurance Plan (QAP), Rev. 7.7, EFR has a choice
regarding purge volumes as follows:

“1. Purging three well casing volumes with a single measurement of field parameters
2. Purging two casing volumes with stable field parameters (within 10% RPD)
3. Purging a well to dryness and stability of a limited list of field parameters after recovery”

Per DWMRC review of the Report, the following purge methods were used during the 3rd Quarter
2023 (including accelerated samples). Purge methods and volumes are summarized in Tab G, on
Table G-1A and G-1B of the Report:

Quarter # Purged 2 Casing
Volumes
# Purged to Dryness # Purged 3 Casing Volumes
3rd Qtr. 2023 25 3 3 (continuous pumping)

When purging two casing volumes, the QAP directs EFR to first calculate the amount of time to
evacuate two casing volumes and then to pump for that length of time. Per DWMRC cross-check
of the field data sheets for each of the reports reviewed, it appears EFR correctly calculated the
well casing volumes and evacuated the required two volumes (when 2 casing volume method
selected) in monitoring wells prior to sample collection during the 3rd Quarter 2023 monitoring
period. Volumes are calculated according to measured pump rates and can be verified by
calibration marks on the collection containers.

During the 3rd Quarter 2023 monitoring period, three monitoring wells were pumped or bailed to
dryness (MW-37, MW-38, and MW-41B). In cases where wells are evacuated to dryness the
QAP Rev. 7.7 (Attachment 2-3) requires that:

“(vii) If the well is purged to dryness:

Record the number of gallons purged on the Field Data Worksheet.

The well should be sampled as soon as a sufficient volume of groundwater is available to fill
sample containers.

Upon arrival at the well after recovery or when sufficient water is available for sampling measure
depth to water and record on the Field Data Worksheet.

Take one set of measurements of field parameters for pH, specific conductance, and temperature
only.

Collect the samples into the appropriate sample containers.
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Take an additional set of measurements of field parameters for pH, specific conductance and
temperature after the samples have been collected.

If the field parameters of pH, specific conductance and temperature are within 10% RPD the
samples can be shipped for analysis.

If the field parameters of pH, specific conductance and temperature are not within 10% RPD,
dispose of the sample aliquots, and purge the well again as described above.

Repeat this process, if necessary, for three complete purging events. If after the third purging the
event, the parameters of pH, specific conductance and temperature do not stabilize to within 10%
RPD, the well is considered sufficiently purged and collected samples can be submitted for
analysis.”

DWMRC staff verified that in cases where the monitoring well was evacuated to dryness and
samples were collected, the number of gallons evacuated was recorded in compliance with the
QAP. Additionally, depth to water before sample collection was recorded on all applicable field
data worksheets which resolved past DWMRC comments.

2. Analytical Laboratories Used by EFR Certified by State of Utah to Perform Analysis
for all Analytes:

The analytical laboratories (GEL Laboratories LLC, Charleston, SC; Chemtech Ford Laboratory,
Sandy, UT) were contracted by EFR to perform analysis on the samples collected during the 3rd
Quarter 2023. Per DWMRC review of the National Environmental Laboratory Accreditation
Management System Website, both laboratories have an active certification within the State of
Utah. Screen prints from the website showing certification status are included in Appendix A.
Upon further cross checking of laboratory certification for specific parameters, it appears that the
EFR contract laboratories were certified to perform analysis for the specified parameters.

3. Laboratory Report Turn Around Times:

Per DWMRC review of Laboratory reports contained in Tab E and Tab F, it was noted that
laboratory report turnaround times for both quarterly and accelerated monitoring was
approximately 27 days for radiological analysis performed by GEL and 14-17 days for all other
analyses performed by Chemtech Ford (not including re-submission/corrected reports). The turn-
around times and EFR data review timelines appear to be reasonable/appropriate.

4. Sample Holding Times:

Per review of the 3rd Quarter 2023 Report (Section 3.4.2, Tab E, Tab F, and Tables G-2A and G-
2B in Tab G of the Report, all method holding times were met for each analyte submitted for
laboratory analysis (for quarterly and accelerated samples). DWMRC staff cross checked all
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holding time requirements and verified that all samples/analytes appeared to be analyzed within
holding times during the 3rd Quarter 2023 reporting period.

5. Sample Preservation:

Per review of the 3rd Quarter 2023 Report (Section 3.4.3, Tab E, Tab F, Tab G), it appears that all
samples required to be chilled (≤6° C) met the temperature preservation requirements. Per review
of the laboratory check in sheets and laboratory QA/QC, no issues related to sample preservation
were noted. Per EFR information and method requirements, samples for gross alpha analysis do
not have a sample temperature requirement.

6. Analytical Reporting Limits:

Per DWMRC review of the quarterly and accelerated electronic laboratory analytical reports as
well as Tables G-5A and G-5B in the 3rd Quarter 2023 Report, it appears that laboratory reporting
limits met the required reporting limits set forth in Table 1 of the QAP.

7. Sample Trip Blank Evaluation:

Per review of the 3rd Quarter 2023 Report, it appears that all trip blank samples met the following
criteria:
- Per Section 3.4.6, Tabs E and F, Table G-6A, and Table G-6B of the 3rd Quarter 2023
Report, all trip blank results associated with the quarterly and accelerated samples
were non detect for volatile organic compounds.
- Per Table G-2A and Table G-2B in Tab G of the Report, all trip blank samples
associated with the quarterly and accelerated samples were analyzed within the
allowed holding time.
- Per Table G-3A and Table G-3B in Tab G of the Report, all trip blank samples
associated with the quarterly and accelerated samples were received by the Laboratory
within an acceptable temperature range.
- Per Table G-5A and Table G-5B in Tab G of the Report, the laboratory reporting limit
for all trip blank samples associated with the quarterly and accelerated samples met the
required reporting limits.

8. Review of Time-Concentration Plots

The Permit Part I.F.1.g requires EFR to submit Time-Concentration Plots for each monitoring
well for primary indicators of cell leakage; chloride, fluoride, sulfate, and uranium. DWMRC
notes that per the discussions with EFR, it was agreed that EFR need not plot trend lines on the
Time Concentration Plots and that all data is included on the plots (no data culled from the set).
Per DWMRC review of the 3rd Quarter 2023 Report, the reviewed plots appear to be in
conformance with the agreed upon changes.

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9. Review of Depth to Groundwater Measurements and Water Table Contour Maps

Per DWMRC cross checks of groundwater elevation measurement calculations used for the 3rd
Quarter 2023, approximately 5% of wells cross checked, comparing surface casing measured
elevations minus measured static levels with plotted elevations, no errors were noted.

The upper wildlife ponds at the White Mesa Mill were taken offline (pond recharge from
Recapture Reservoir discontinued) during the 2nd Quarter 2011 to re-establish groundwater
contours. Hydrographs of the upper wildlife pond ground water piezometers (Water Level
Elevation vs. Time) are included in Appendix B (Northern piezometers and southern
piezometers). It was also noted that the static water levels in several monitoring wells close to the
upper wildlife ponds showed significant decrease in water levels since the ponds were taken
offline. These declines can be attributed to natural dissipation of the area ground water mound
and/or ground water pumping activities related to corrective action of nitrate and chloroform
contamination plumes (development of cone of depressions around pumping wells).

Nitrate and Chloroform Corrective Action Plan Pumping Wells:

Ground water elevations are being impacted by effects from ground water pumping for the nitrate
and chloroform contamination plume remediation. The following monitoring wells have been
converted to active pumping wells:

Nitrate Pumping Wells – TW4-22, TW4-24, TW4-25, TWN-2 (The nitrate pumping project was
initiated during January 2013).

Chloroform Pumping Wells – MW-4, MW-26, TW4-1, TW4-2, TW4-4, TW4-11, TW4-19, TW4-
21, TW4-22, TW4-24, TW4-25, TW4-37, TW4-39.

The pumping wells for both the nitrate and chloroform projects are set up with a delay device
wherein the wells purge for a set amount of time then shut off to let the well recharge. All
pumping wells include a flow meter which records the volume of water pumped from the well in
gallons. Quarterly nitrate and chloroform reports are prepared by EFR and include pump volumes
and delineation of pump capture zones based on kriged water contours. DWMRC expects that
ground water elevation contours will continue to adjust in response to the pumping activities and
discontinuance of recharge to the upper wildlife ponds.

12. Conclusions and Recommendations

Per the Division review it appears that the Report complies with Permit and QAP. Therefore, a
letter will be drafted notifying EFR of the review and closing out of the November 7, 2023, 3rd
Quarter, 2023 Groundwater Report.

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13. References

1 Energy Fuels Resources (USA) Inc., November 7, 2023, 3rd Quarter 2023 Groundwater
Monitoring Report, Groundwater Discharge Permit UGW370004, White Mesa Uranium Mill.

2 Energy Fuels Resources (USA) Inc., October 25, 2023, State of Utah Ground Water Discharge
Permit No. UGW370004 White Mesa Uranium Mill – Notice Pursuant to Part I.G.1(a).

3 Energy Fuels Resources (USA) Inc., February 15, 2022, White Mesa Uranium Mill Ground
Water Monitoring Quality Assurance Plan (QAP), Revision 7.7.

4 INTERA Incorporated, 2007, Revised Background Groundwater Quality Report: Existing Wells
for Dension Mines (USA) Corp.’s White Mesa Uranium Mill Site, San Juan County, Utah.

5 INTERA Incorporated, 2007, Background Groundwater Quality Report: New Wells for Denison
Mines (USA) Corp.’s White Mesa Uranium Mill Site, San Juan County, Utah.

6 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 located near Blanding Utah. Prepared by University of
Utah Department of Geology and Geophysics.

7 Utah Department of Environmental Quality, March 8, 2021, Modified Utah Ground Water
Discharge Permit No. UGW370004 issued for the Energy Fuels Resources (USA) Inc. White Mesa
Uranium Mill.

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Appendix A – State of Utah Laboratory Certifications

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Appendix B – Hydrographs of the Upper Wildlife Pond
Groundwater Piezometers

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