DRC-2023-077586 - 0901a068812c5a06

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: September 5, 2023

SUBJECT: Review of the Energy Fuels Resources (USA) Inc. 2nd 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, July 27, 2023, Transmittal of 2nd Quarter 2023 Groundwater Monitoring Report
Groundwater Quality Discharge Permit UGW370004 White Mesa Uranium Mill.
(Received by the Division on August 1, 2023)
2. EFR, July 11, 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 July 14, 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 2nd 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

S-
EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 2

(see the Permit, Part I.G.1). Three new compliance parameters went into accelerated monitoring
frequency POOC based on sampling during the 2nd 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 below lists monitoring wells with parameters currently in OOC or POOC status as of the
2nd 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 Total Dissolved Solids
Chloride
3rd Quarter 2021
4th Quarter 2022
November 2021
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
EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 3

Well Class *Position Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
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
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

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-12 Class III water D-3 Uranium
Selenium
2nd Quarter 2017
2nd Quarter 2020
3rd Quarter 2017
3rd Quarter 2020
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 1st Quarter 2015 2nd Quarter 2015
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 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 4

Wells Monitored Semi-annually Accelerated to Quarterly Monitoring

Well Water
Class
*Position 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 – Chloride first exceeded the GWCL of 39.19 mg/L during the 3rd Quarter 2019
sampling event. Accelerated monthly sampling began in November 2019. Since then, Chloride
has exceeded the GWCL regularly. Concentrations of Chloride in MW-11 since 2019 have been
significantly higher than the average from 2005-2019. 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 schedule for assessment to address the
consecutive exceedance is not necessary. In the 2nd Quarter 2023, Chloride exceeded the GWCL
during all three monthly accelerated sample events.

Sulfate - Sulfate first exceeded the GWCL of 1,309 mg/L during the 3rd Quarter 2019 sampling
event performed in July. Accelerated monthly sampling began in November 2019. The first
consecutive exceedances occurred in July and August 2021. Since August 2021, Sulfate has
exceeded the GWCL in 7 of the 22 monthly sample events. A Source Assessment Report (SAR)
was submitted on March 7, 2022. The GWCLs were recalculated and will become effective on
the next revision of the GWDP. A 30-day plan and schedule for assessment to address the
consecutive exceedance is not necessary. In the 2nd Quarter 2023, Sulfate exceeded the GWCL
during the April and June monthly sample events.

Total Dissolved Solids (TDS) – TDS first exceeded the GWCL of 2,528 mg/L during the 3rd
Quarter 2020 sampling event performed in July. Accelerated monthly sampling began in
November 2020. The first consecutive exceedances occurred in July and August 2021. Since
then, TDS has exceeded the GWCL in only 2 of the 21 monthly sample events and never on
consecutive occasions. TDS did not exceed the GWCL during sampling performed in 2nd Quarter
2023. 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 submitted
on July 11, 2023 and approved by DWMRC. TDS will return to normal frequency sampling in
the 3rd Quarter 2023.

Manganese - Manganese first had consecutive exceedances of the original GWCL during the 1st
and 2nd Quarter 2010 sampling events. Exceedances frequently occurred during accelerated
monthly sampling until a revised GWCL of 237 ug/L was approved for the 2nd Quarter 2021
sampling event. Consecutive exceedances again occurred during the 3rd and 4th Quarter 2021
sampling events. 8 of the last 11 accelerated monthly sample results have been below the GWCL,
EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 5

however during the 2nd Quarter 2023, Manganese exceeded the GWCL during the June sample
event.

Nitrate + Nitrite (as N) first exceeded the GWCL of 2.5 mg/L during the 1st Quarter 2022
sampling event. Accelerated monthly sampling began in May 2022. Consecutive exceedances
occurred during the September and October 2022 sampling events. Since then, 7 of the last 8
accelerated monthly sample results have been above the GWCL. A CAP was approved in 2012
addressing Nitrate + nitrite and chloride in monitoring wells and activities associated with the
CAP are on-going. A 30-day plan and schedule for assessment to address the consecutive
exceedance is not necessary.

Selenium - Selenium first had an exceedance of the 12.5 ug/L GWCL in the 3rd Quarter 2022
sampling event in October. A second consecutive exceedance occurred in the 4th Quarter 2022.
Accelerated monthly sampling began in February 2023 and all sample events in the 2nd quarter
2023 exceeded the GWCL. A 30-day plan and schedule for assessment was submitted in May
2023 and approved by DWMRC.

Well Water
Class
*Position Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-25 Class III
water
Downgradient
of Cell 3
Total Dissolved Solids
Chloride
3rd Quarter 2021
4th Quarter 2022
November 2021
March 2023

Total Dissolved Solids (TDS) – TDS first exceeded the GWCL of 2,976 mg/L during the 3rd
Quarter 2021 sampling event. Accelerated monthly sampling began in November 2021. Since
then, the only exceedance of the GWCL was in April 2022. TDS did not exceed the GWCL
during sampling performed in Q2 2023. At the conclusion of the 1st quarter 2023, TDS had not
exceeded the GWCL for the last 11 monthly sample events. A request for removal of TDS from
accelerated sampling was submitted on April 25, 2023 and approved by DWMRC. TDS will
return to normal frequency sampling in Q3 2023.

Chloride – Chloride first exceeded the GWCL during the 3rd Quarter 2015 sampling event.
Accelerated monthly sampling began in January 2016 and after successive non-exceedances,
sampling resumed to quarterly. Another exceedance of the GWCL did not occur until the
4th Quarter 2022 sampling event when the concentration was 35.8 mg/L, just above the current
GWCL of 35 mg/L. Accelerated monthly sampling began in the 1st Quarter 2023. Since then,
Chloride exceeded the GWCL during the April and June monthly sampling events in the 2nd
Quarter 2023. Concentrations were again just over the GWCL of 35 mg/L (35.8 mg/L and 35.2
mg/L respectively).

EFR 2nd 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-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

Nitrate + Nitrite (as N) exceeded the GWCL during all of the 2nd Quarter 2023 sampling events.
Nitrate + Nitrite (as N) initially had consecutive exceedances of the GWCL during the 1st and 2nd
Quarter 2010 sampling events. Accelerated monthly sampling began in May 2010. MW-26 is
located downgradient and in close proximity to the Nitrate plume. A CAP addressing Nitrate +
nitrite and chloride in monitoring wells was approved in 2012. Activities associated with the CAP
are on-going and the 30-day plan and schedule for assessment is not required at this time.

Chloroform – Chloroform exceeded the GWCL during all of the 2nd Quarter 2023 sampling
events. MW-26 is a pumping well for chloroform removal. Per DWMRC approval in 2011,
exceedances of the GWCL are expected to occur and the 30-day plan and schedule for assessment
is not required at this time.

Chloride – Chloride first exceeded the GWCL of 58.31 during the 1st Quarter 2010 sampling
event in February. Accelerated monthly sampling began in May 2010. MW-26 lies within the
Nitrate plume and exceedances (including consecutive) of the GWCL have occurred regularly
since 2010 including during each of the monthly sample events in the 2nd Quarter 2023. A CAP
addressing Nitrate + nitrite and chloride in monitoring wells was approved in 2012. Activities
associated with the CAP are on-going and the 30-day plan and schedule for assessment is not
required at this time.

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) exceeded the GWCL during all of the 2nd Quarter 2023 sampling events.
Nitrate + Nitrite (as N) initially had consecutive exceedances of the GWCL during the 1st and 2nd
Quarter 2010 sampling events. Accelerated monthly sampling began in May 2010. MW-30 lies
within the Nitrate plume. A CAP addressing Nitrate + nitrite and chloride in groundwater was
approved in 2012. Activities associated with the CAP are on-going and the 30-day plan and
schedule for assessment is not required at this time.

EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 7

Chloride – Chloride exceeded the GWCL during all of the 2nd Quarter 2023 sampling events.
Chloride initially had consecutive exceedances of the GWCL during the 1st and 2nd Quarter 2011
sampling events. Accelerated monthly sampling began in May 2011. MW-30 lies within the
Nitrate plume. A CAP addressing Nitrate + nitrite and chloride in monitoring wells was approved
in 2012. Activities associated with the CAP are on-going and the 30-day plan and schedule for
assessment is not required at this time.

Uranium - Uranium first had an exceedance of the 8.32 ug/L GWCL in the 4th Quarter 2011
sampling event. Accelerated monthly sampling began in March 2012. Exceedances frequently
occurred after, and a SAR was submitted in 2022. The GWCLs were recalculated and will
become effective in the next revision of the GWDP. Uranium exceeded the GWCL in 2 of the 3
2nd Quarter 2023 accelerated monthly sampling events.

Selenium - Selenium first had an exceedance of the GWCL in the 2nd Quarter 2010 sampling
event. Accelerated monthly sampling began in July 2010. Exceedances frequently occurred after,
and the GWCL was revised to 47.2 during the 2018 GWDP revision. Consecutive exceedances of
the GWCL occurred again during the 1st and 2nd Quarter 2019 sampling events. Accelerated
monthly sampling resumed in May 2019. A SAR was submitted in 2022 and consequently the
GWCLs were recalculated and will become effective in the next revision of the GWDP. Selenium
exceeded the GWCL in all of the 2nd Quarter 2023 sampling events.

Field pH – MW-30 was sampled for Field pH monthly beginning in 2007. The first exceedance
occurred in June 2011. Exceedances (including consecutive) occurred during monthly sampling
from 2011-2018, however from 2019 until the present only two exceedances have occurred. Field
pH was within the GWCL during all three of the 2nd Quarter 2023 sampling events and has been
within the GWCL range during the last 7 sample events.

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) exceeded the GWCL during all of the 2nd Quarter 2023 sampling events.
Nitrate + Nitrite (as N) initially had consecutive exceedances of the GWCL during the 1st and 2nd
Quarter 2010 sampling events. Accelerated monthly sampling began in May 2010. MW-31 lies
within the Nitrate plume. A CAP addressing Nitrate + nitrite and chloride in groundwater was
approved in 2012. Activities associated with the CAP are on-going and the 30-day plan and
schedule for assessment is not required at this time.

EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 8

Chloride – Chloride exceeded the GWCL during all of the 2nd Quarter 2023 sampling events.
Chloride initially had consecutive exceedances of the GWCL during the 1st and 2nd Quarter 2011
sampling events. Accelerated monthly sampling began in May 2011. MW-31 lies within the
Nitrate plume. A CAP addressing Nitrate + nitrite and chloride in monitoring wells was approved
in 2012. Activities associated with the CAP are on-going and the 30-day plan and schedule for
assessment is not required at this time.

Total Dissolved Solids (TDS) – TDS first had consecutive exceedances of the original GWCL
during the 3rd and 4th Quarter 2010 sampling events. Accelerated monthly sampling began in
January 2011. Exceedances continued during accelerated sampling until a revised GWCL of
2,132 mg/L was approved for the 2nd Quarter 2019 sampling event and sampling was once again
moved to quarterly. After consecutive exceedances in the 3rd and 4th Quarter 2019, TDS was
moved to accelerated monthly sampling in November 2019. A SAR was submitted in 2020 and
consequently the GWCL was recalculated and will become effective in the next revision of the
GWDP. TDS exceeded the GWCL during all of the 2nd Quarter 2023 monthly accelerated
sampling events.

Sulfate – Under the current GWCL established during the 2019 GWDP revision, Sulfate had
consecutive exceedances of the 993 mg/L GWCL during the 3rd and 4th Quarter 2019 sampling
events. Accelerated monthly sampling began in November 2019. A SAR was submitted in 2020
and consequently the GWCL was recalculated and will become effective in the next revision of
the GWDP. As such, a 30-day plan and schedule for assessment is not required at this time.
Sulfate exceeded the GWCL during all of the 2nd Quarter 2023 monthly accelerated sampling
events.

Uranium - Under the current GWCL of 15 ug/L established during the 2019 GWDP revision,
Uranium had consecutive exceedances in the 2nd and 3rd Quarter 2020 sampling events.
Accelerated monthly sampling began in August 2020. A SAR was submitted in 2021 and
consequently the GWCL was recalculated and will become effective in the next revision of the
GWDP. As such, a 30-day plan and schedule for assessment is not required at this time. Uranium
exceeded the GWCL during all of the 2nd Quarter 2023 monthly accelerated sampling events.

EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 9

Wells Monitored Semi-annually Accelerated to Quarterly Monitoring

Well Water
Class
*Position 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 first exceeded the current GWCL of 109.58 ug/L in the 1st Semi-annual
sampling event of 2023 in April. Accelerated quarterly sampling will now be performed starting
with the 3rd Quarter 2023 sampling event.

Well Water
Class
*Position 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 – Uranium first exceeded the current GWCL of 7.5 ug/L in the 1st Semi-annual
sampling event of 2023 in April. Accelerated quarterly sampling will now be performed starting
with the 3rd Quarter 2023 sampling event.

Well Water
Class
*Position Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-12 Class III
water
Downgradient
of Cell 3
Uranium
Selenium
2nd Quarter 2017
2nd Quarter 2020
3rd Quarter 2017
3rd Quarter 2020

Uranium – Uranium first had an exceedance of the 23.5 ug/L GWCL in the 1st 2017 semi-annual
sampling event in April. Accelerated quarterly sampling began in the 3rd Quarter 2017. Since that
time Uranium has exceeded the GWCL in 5 of the 23 quarterly sampling events at concentrations
just exceeding the GWCL. At the conclusion of the 1st quarter 2023, Uranium had not exceeded
the GWCL for the last 8 monthly sample events. A request for removal of Uranium from
accelerated sampling was submitted on April 25, 2023 and approved by DWMRC. Uranium will
return to normal frequency sampling in the 3rd Quarter of 2023. Uranium did not exceed the
GWCL during any of the 2nd Quarter 2023 sampling events.

Selenium – Under the current GWCL of 39 ug/L established during the 2018 GWDP revision,
Selenium first exceeded the GWCL in the 2nd Quarter 2020. Consecutive exceedances occurred
during accelerated quarterly sampling in the 3rd and 4th Quarter 2020 sampling events. At the
conclusion of the 1st quarter 2023, Selenium had not exceeded the GWCL for the last 9 monthly
sample events. A request for removal of Selenium from accelerated sampling was submitted on
April 25, 2023 and approved by DWMRC. Selenium will return to normal frequency sampling in
EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 10

the 3rd Quarter of 2023. Selenium did not exceed the GWCL during any of the 2nd Quarter 2023
sampling events.

Well Water
Class
*Position 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 first exceeded the 46.8 mg/L GWCL during the 2nd Semi-Annual sampling
event of 2022 in October. 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 2nd
Quarter 2023 sampling event.

Well Water
Class
*Position 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

Beryllium – Beryllium first exceeded the GWCL of 2 ug/L during the 2nd Semi-Annual sampling
event of 2017 in October. Accelerated quarterly sampling was initiated during the 3rd Quarter
2018. Following a non-exceedance in the 3rd Quarter 2018, Beryllium has exceeded the GWCL in
all of the quarterly accelerated sampling events since. A SAR was approved by DWMRC in 2019
to study trends in MW-24 and is currently still ongoing. A plan and schedule for assessment of
consecutive exceedances is not required.

Cadmium – Cadmium first exceeded the current GWCL of 6.43 ug/L established during the 2018
GWDP revision in the 1st Semi-Annual sampling event of 2018 in April. Accelerated quarterly
sampling was initiated during the 3rd Quarter 2018. Since then, Cadmium has exceeded the
GWCL in all of the quarterly accelerated sampling events. A SAR was approved by DWMRC in
2019 to study trends in MW-24 and is currently still ongoing. A plan and schedule for assessment
of consecutive exceedances is not required.

Thallium – Thallium first exceeded the current GWCL of 2.01 ug/L established during the 2018
GWDP revision in the 1st Semi-Annual sampling event of 2018 in April. Accelerated quarterly
sampling was initiated during the 3rd Quarter 2018. Since then, Thallium has exceeded the
EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 11

GWCL in 18 of the 19 quarterly accelerated sampling events. A SAR was approved in 2019 to
study trends in MW-24 and is currently still ongoing. A plan and schedule for assessment of
consecutive exceedances is not required.

Field pH – Field pH first exceeded the current GWCL limits of 5.03-8.5 established during the
2018 GWDP revision in the 1st Semi-Annual sampling event of 2018 in April. Accelerated
quarterly sampling was initiated during the 3rd Quarter 2018. Since then, Field pH has tested
outside the GWCL limits in 13 of the 19 quarterly accelerated sampling events. A SAR was
approved by DWMRC in 2019 to study trends in MW-24 and is currently still ongoing. A plan
and schedule for assessment of consecutive exceedances is not required.

Fluoride – Fluoride first exceeded the current GWCL of 0.47 mg/L established during the 2018
GWDP revision in the 2nd Semi-Annual sampling event of 2018 in October. Accelerated quarterly
sampling was initiated during the 3rd Quarter 2019. Since then, Fluoride has exceeded the GWCL
in all of the quarterly accelerated sampling events. A SAR was approved by DWMRC in 2019 to
study trends and is currently still ongoing. A plan and schedule for assessment of consecutive
exceedances is not required.

Nickel – Nickel first exceeded the 50 ug/L GWCL during the 2nd Semi-Annual sampling event of
2018 in October. Accelerated quarterly sampling was initiated during the 3rd Quarter 2019. Since
then, Nickel has exceeded the GWCL in all of the quarterly accelerated sampling events. A SAR
was approved by DWMRC in 2019 to study trends in MW-24 and is currently still ongoing. A
plan and schedule for assessment for consecutive exceedances is not required.

Manganese– Manganese first exceeded the 7,507 ug/L GWCL during the 2nd Semi-Annual
sampling event of 2019 in November. Accelerated quarterly sampling was initiated during the 1st
Quarter 2020. Since then, Manganese has exceeded the GWCL in 7 out of the 13 quarterly
accelerated sampling events including during consecutive sample events. A SAR was approved
by DWMRC in 2019 to study trends in MW-24 and is currently still ongoing. A plan and
schedule for assessment for consecutive exceedances is not required.

Sulfate – Sulfate first exceeded the 2,903 mg/L GWCL during the 4th Quarter 2009 sampling
event. Another exceedance occurred during the 2nd Semi-Annual sampling event of 2014 in
November. Accelerated quarterly sampling was performed until the 2018 GWDP revision and no
exceedances occurred until the 1st Quarter 2020 sampling event. Since then, Sulfate has exceeded
the GWCL in 8 out of the 13 quarterly accelerated sampling events including during consecutive
sample events. A SAR was approved by DWMRC in 2019 to study trends in MW-24 and is
currently still ongoing. A plan and schedule for assessment for consecutive exceedances is not
required.

Gross Alpha – Gross Alpha had the first and only exceedance of 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. No exceedances have occurred in the 10 sample events
since.

EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 12

Total Dissolved Solids (TDS) – TDS first exceeded the GWCL of 4,450 mg/L during the 1st
Semi-Annual sampling event of 2021 in April. Accelerated quarterly sampling began in the 3rd
Quarter 2021. Following non-exceedances in the 3rd and 4th Quarters of 2021, TDS has not
exceeded the GWCL since. A SAR was approved in 2019 to study trends in MW-24 and is
currently still ongoing. A plan and schedule for assessment for consecutive exceedances is not
required.

Well Water
Class
*Position 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) - Quarterly sampling for Nitrate + Nitrite (as N) has been occurring
since the 3rd Quarter 2007 and first exceeded the 5.6 mg/L GWCL during the 2nd Quarter 2008
sampling event. MW-27 is in close proximity to 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 plan and time schedule for assessment is not required. In the previous 4 quarterly sampling
events including the 2nd Quarter 2023, Nitrate + Nitrite (as N) has been below the GWCL.

Fluoride – Fluoride has been sampled semi-annually since 2010. Fluoride had the first and only
exceedance of the 0.85 mg/L GWCL during the 1st Semi-Annual sampling event of 2022 in April.
Accelerated quarterly sampling was initiated during the 3rd Quarter 2022. No exceedances have
occurred since.

Well Water
Class
*Position 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 – Quarterly sampling for Chloride has occurred from 2005 until the present. Chloride
first exceeded the 105 mg/L GWCL during the 2nd Quarter 2010 sampling event. Since then,
Chloride has exceeded the GWCL in nearly every quarterly sampling event including the 2nd
Quarter 2023. MW-28 is downgradient from and in close proximity to 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 plan and schedule for assessment of consecutive
exceedances is not required.

Uranium – Quarterly sampling for Uranium first occurred from 2005 – 2009. In 2010, semi-
annual sampling began and the first exceedance of the 4.9 ug/L GWCL was during the 1st 2014
semi-annual sampling event in April. Accelerated quarterly sampling began in the 3rd Quarter
2014. Since then, Uranium has exceeded the GWCL in 26 of the 36 quarterly sampling events
EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
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including during the 2nd Quarter 2023 sampling event. A SAR was submitted in 2020 and
consequently the GWCL was recalculated and will become effective in the next revision of the
GWDP. A plan and schedule for assessment of consecutive exceedances is not required.

Selenium – Selenium first exceeded the GWCL of 11.1 ug/L during the 1st 2019 semi-annual
sampling event in April. Accelerated quarterly sampling began in the 3rd Quarter 2019. Since
then, Selenium has exceeded the GWCL in 12 of the 16 quarterly sampling events including
during the 2nd Quarter 2023 sampling event. A SAR was submitted and approved by DWMRC in
2020 and a recalculated GWCL will become effective in the next revision of the GWDP. A plan
and schedule for assessment of consecutive exceedances is not required.

Nitrate + Nitrite (as N) - Quarterly sampling for Nitrate + Nitrite (as N) first occurred from 2005
to 2009. In 2010, semi-annual sampling began and the first exceedance the 5 mg/L GWCL was
during the 2nd 2019 semi-annual sampling event in October. Accelerated quarterly sampling
began in the 3rd Quarter 2020. Consecutive exceedances occurred in the 2nd, 3rd, and 4th quarters
of 2022 but have not occurred since. MW-28 is downgradient from and in close proximity to 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 plan and schedule for assessment of
consecutive exceedances is not required.

Well Water
Class
*Position Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-29 Class III
water
Downgradient
of Cell 2 Uranium 1st Quarter 2020 3rd Quarter 2021

Uranium – Quarterly sampling for Uranium first occurred from 2005 – 2009. In 2010, semi-
annual sampling began and the first exceedance of the 15 ug/L GWCL was during the 2nd semi-
annual sampling event of 2020 in April. Accelerated quarterly sampling began in the 1st Quarter
2021. Since then, Uranium has exceeded the GWCL in 10 of the 12 quarterly sampling events
including during the 2nd Quarter 2023 sampling event. A SAR was submitted on September 7,
2021. The GWCLs were recalculated and will become effective on the next revision of the
GWDP. A 30-day plan and schedule for assessment to address the consecutive exceedance is not
necessary.

Well Water
Class
*Position Parameter Date of First
Exceedance of
GWCL
Date Accelerated
Monitoring First
Required
MW-32 Class III
water
Cross-
Gradient of
Cell 2
Chloride 1st Quarter 2015 2nd Quarter 2015

Chloride – Quarterly sampling for Chloride has occurred from 2005 until the present. Chloride
first exceeded the 35.39 mg/L GWCL during the 2nd Quarter 2014 sampling event. Since then,
EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 14

Chloride has exceeded the GWCL in 22 of the last 34 quarterly sampling events including the 2nd
Quarter 2023 sampling event. MW-32 is downgradient from and in close proximity to 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 plan and schedule for assessment of
consecutive exceedances is not required.

Well Water
Class
*Position 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 – Field pH was first sampled quarterly from 2011 – 2017. During that time, Field pH
exceeded the GWCL limits of 6.61 - 8.5 in 8 of the 26 quarterly accelerated sampling events. In
2018 semi-annual sampling began. Since then, Field pH first exceeded the GWCL limits during
the 2nd Semi-Annual sampling event of 2022 in November. Accelerated quarterly sampling was
initiated during the 1st Quarter 2023 and Field pH had the first consecutive exceedance of the
GWCL limits. A plan and schedule for assessment was submitted in May 2023 and was approved
by DWMRC.

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 2nd 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
2nd Qtr. 2023 32 5 4 (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 2nd Quarter 2023 monitoring
EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
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period. Volumes are calculated according to measured pump rates and can be verified by
calibration marks on the collection containers.

During the 2nd Quarter 2023 monitoring period, five monitoring wells were pumped or bailed to
dryness. 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.

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.

EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 16

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 2nd
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 (from date of EFR sample submission to the contract
laboratory) for both quarterly and accelerated monitoring was approximately 30 days for
radiological analysis performed by GEL and 20 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 2nd 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
holding time requirements and verified that all samples/analytes appeared to be analyzed within
holding times during the 2nd Quarter 2023 reporting period.

5. Sample Preservation:

Per review of the 2nd 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 2nd Quarter 2023 Report, it appears that laboratory reporting
limits met the required reporting limits set forth in Table 1 of the QAP.

EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 17

7. Sample Trip Blank Evaluation:

Per Section 3.4.6, Tabs E and F, Table G-6A, and Table G-6B of the 2nd Quarter 2023 Report, all
trip blank results associated with the quarterly, semi-annual, and accelerated samples were non
detect for volatile organic compounds. Per Table G-2A and Table G-2B in Tab G of the 2nd
Quarter 2023 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
2nd Quarter 2023 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 2nd Quarter 2023 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 2nd Qtr. 2023 Report, the reviewed plots appear to be in conformance
with the agreed upon changes.

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

Per DWMRC cross checks of groundwater elevation measurement calculations used for the 2nd
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 below (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:

EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
Page 18

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 July 27, 2023, 2nd Quarter,
2023 Groundwater Report.

13. References

1 Energy Fuels Resources (USA) Inc., July 27, 2023, 2nd Quarter 2023 Groundwater Monitoring
Report, Groundwater Discharge Permit UGW370004, White Mesa Uranium Mill.

2 Energy Fuels Resources (USA) Inc., July 11, 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.
EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
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Appendix A – State of Utah Laboratory Certifications

EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
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EFR 2nd Quarter 2023 Groundwater Monitoring Report
DWMRC Review Memo
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