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State of Utah
SPENCER J Cox
Governor
DIEDRE 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: Project File L-2016-93
THROUGH: Phil Goble, Section Manager (9,C
FROM: Russell J. Topham, PE /fr
DATE: June 15, 2020
SUBJECT: Review of 2020 Impoundment 2 Reclamation Cover Annual Performance Monitoring
Report
Energy Fuels Resources (USA), Inc. (EFR) White Mesa Uranium Mill, Blanding, Utah
Ground Water Discharge Permit Number UGW370004 (GWDP)
This Memorandum discusses the performance to date of the test cells installed to evaluate the proposed
ET Cover system at the White Mesa Uranium Mill south of Blanding, Utah. More specifically, this
Memorandum discusses hydrologic characteristics, including erosion protection and percolation
prevention performance, and adherence to the vegetation speciation and density criteria presented in the
Stipulation and Consent Agreement discussed below. The purpose of this Memorandum is to capture
thoughts and observations regarding the cover test effort for use should the author not be called upon to
follow the testing protocol to the end of the study period.
The background section below is included both to identify what is intended for inclusion in this
Memorandum and to capture references to related, parallel work that are beyond the scope of this
Memorandum for the use of the individual assigned to carry this work forward.
As detailed below, the test cells appear to be on a trajectory to fail the plant density and diversity targets.
Recognizing this, additional data collection at a second supplemental test section has been initiated in
support of contemplated modeling as an alternative means to demonstrate likely success of the ET cover
concept at the mill. The State has been in a protracted drought, so the percolation monitoring results
may not be representative of a wetter cycle.
DRC-20 195 North 1950 West • Salt Lake City, UT
Mailing Address. P 0 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
Review Memorandum, Project L-2016-93, Reclamation Cover Test Monitoring
June 15, 2021
Page 2
Background
10 CFR 40 Appendix A Criterion 4(d) requires the installation of "[a] full self-sustaining vegetative
cover [...] or rock cover [...] to reduce wind and water erosion to negligible levels." The Division
recognizes that both the vegetative cover and rock cover have advantages and disadvantages, a
discussion of which are beyond the scope of this memorandum. It is sufficient to note that the rock
cover design is more prone to infiltration of precipitation into the tailings mass below than a properly
functioning vegetative cover, but the vegetative cover is more susceptible to erosion under the influence
of runoff water and wind.
The license renewal extended to EFR in 2018 included an updated reclamation plan, Reclamation Plan
5.1B (the Reclamation Plan)1. The Reclamation Plan included the legacy cover system approved in
1978 with the original design and carried forward into reclamation Plan 3.2B2 and a new
evapotranspirative (vegetative) cover design (the ET cover)3. The ET cover concept has not been shown
to work well in arid climates, such as that at the White Mesa uranium mill site near Blanding.4 As a
result, approval of the reclamation plan was extended with the inclusion of a Stipulation and Consent
Agreement (the SCA) governing the process of evaluating the ET cover for approval or reversion to the
legacy rock cover system.5
Inasmuch as the legacy cover is fully approved, it will not be discussed further here, except where
comparison and contrast with the proposed ET Cover is desired.
The Stipulation and Consent Agreement (SCA) provides a framework for evaluating and approving or
denying approval for the proposed ET cover system. Statutory authority, statutory and regulatory
provisions and relevant facts governing the installation and monitoring of test cells to evaluate the
performance of the proposed ET Cover design are stated in SCA Sections A through C and need not be
repeated here. Documents cited therein are incorporated here by reference.
Impoundment 2 has received tailings to capacity and has been closed to receipt of additional tailings in
the impoundment or to burial of lle.(2) byproduct from decommissioning of In-Situ Leach Recovery
facilities in its cap. Recognizing the need to provide better radon protection at Impoundment 2 than
existed at the time the SCA was crafted, 6 the SCA divided the proposed ET cover construction into two
1 02 2018, Reclamation Plan 5.1B, DRC-2018-001449. Future references to the Reclamation Plan will include the words
"Reclamation Plan" followed by the pertinent section or page number(s), whether cited in the text or in the footnotes.
2 Reclamation Plan Section 5.3.
3 Reclamation Plan Section 3 and Appendix A. Note that Appendix A was originally prepared as a stand-alone design report
and contains several internal appendices. Thus, references like "Appendix L to Appendix A" will refer to Appendix L in the
Updated Tailings cover Design Report which appears as Appendix A to Reclamation Plan 5.1B.
4 10 CFR 40 Appendix A Criterion 4(d): "Where a full vegetative cover is not likely to be self-sustaining due to climatic or
other conditions, such as in semi-arid and arid regions, rock cover must be employed on slopes of the impoundment system."
5 2017 02 23 Executed Stipulation and Consent Agreement, White Mesa Uranium Mill, Radioactive Materials License
Number UT 1900479. Future references to the Stipulation and Consent Agreement will include the abbreviation "SCA"
followed by the pertinent section or paragraph number(s), whether cited in the text or in the footnotes. References in the
SCA to Appendix L, or of the form "Section 1.2" refer to Appendix L in the Updated Tailings cover Design Report which
appears as Appendix A to Reclamation Plan 5.1B.
6 10 CFR 40 Appendix A Criterion 6(1)(ii).
Review Memorandum, Project L-2016-93, Reclamation Cover Test Monitoring
June 15, 2021
Page 3
phases for Impoundment 2.7 The material installed meets the design criteria for the lower two layers of
the proposed ET cover and exceeds the specifications for the radon barrier portion of the legacy cover.
The installation was observed and approved previously and is not a subject of this Memorandum.8
Construction of the Primary and Secondary Test Sections (the Primary and Secondary Test Cells) were
completed and reviewed elsewhere9, and the construction effort will not be discussed here. This
Memorandum is an interim evaluation of the performance of these Test Cells to capture observations
and analyses made to date.
The Primary Test Section includes a suite of sensors to collect and record hydrologic data in real time.
The monitoring period specified to study the ET design included two full years of calibration monitoring
followed by five years of active evaluation. The calibration period was intended to allow vegetation to
mature and sensors and data collectors to be calibrated. Additionally, reporting protocols could be tried
and adjusted.
EFR provided quarterly Data Quality Reports and annual analyses beginning in the fourth quarter of
2017 and continued through the calibration period. The annual reports include all quarterly data, so
evaluation of the annual reports will suffice to understand the performance of the cover system as
represented by the test cells. The calibration period ended, and cover performance monitoring
commenced on January 1, 2020.The calibration data will not be used for compliance determination, so it
will not receive further attention here.
The Secondary Test Section was constructed to simulate extended stormwater run-on and runoff
conditions and the potential for animal intrusion to damage the cover. No quantitative analysis of the
reports for the Secondary Test Cell will be prepared at this point. The Secondary Test Cell is producing
significantly less vegetation. Notwithstanding the lack of vegetation, erosion has not been observed.
Furthermore, with sparse plant cover, animals have not intruded. The Secondary Test Cell will receive
scrutiny at as the testing period draws to a close.
Results of the 2020 Monitoring Period
This is a summary of Utah Division of Waste Management and Radiation Control (DWMRC) staff
review of the EFR Impoundment 2 Reclamation Cover Annual Performance Monitoring Report dated
February 22, 2021, for calendar year 2020 (Report). DWMRC received the Report on March 5, 2021 in
both hard copy and CD formats. Cover performance monitoring commenced on January 1, 2020.
Discussions in this document reference the Stipulation and Consent Agreement (SCA), dated February
3, 2017 and Reclamation Plan, Revision 5.1B. Appendix A to Reclamation Plan, Revision 5.1B is the
Updated Tailings Cover Design Report, which included as its Appendix L (Appendix L) performance
requirements for the cover system. Appendix L includes construction details which are beyond the scope
7 SCA TT C.4, C.8, C.11, D.1, D.8.
8 See Division Project #C-2016-94. Closeout letter dated January 19, 2018, DRC-2018-000401.
9 For the Primary Test Section or Cell, see As-Built Report, DRC-2017-004903; Memorandum, DRC-2017-006427; Closeout
Letter, DRC-2017-006246. The Supplemental Test Section or Cell was constructed several months after the Primary Cell;
see As Built Report, DRC-2018-001861; notes in Memorandum of Inspection DRC-2019-002684; Closeout Letter, DRC-
2018-004521.
Review Memorandum, Project L-2016-93, Reclamation Cover Test Monitoring
June 15, 2021
Page 4
of this review. This review focuses on the performance of the cover system, including plant speciation
and water balance (percolation rate and apparent evaporation and transpiration of precipitated moisture).
The SCA includes the following quotation from EFR's August 15, 2015 Response to Comments on the
Reclamation Plan:
Conceptually, the model simulation results are in agreement with the general consensus that the
establishment of vegetation is the most critical factor in reducing long-term infiltration rates
through an ET cover system. For this reason, among other factors mentioned below, infiltration
rates are only presented for a 40 percent vegetative cover scenario. Forty percent vegetative
cover is the targeted reclamation goal success criterion, and is supported by vegetation
reconnaissance near the site and studies published in the literature.1°
Without sufficient plant density, the cover may not transpire sufficient moisture to prevent infiltration.
If the cover test fails to meet plant density and diversity criteria or percolation rate benchmarks EFR has
the option to demonstrate through modeling that the cover system will still provide the required
protection against percolation."
Performance Criteria
Appendix L, Section L.4.2. provides three performance criteria:
1. The percolation rate cannot exceed 2.3 mm/yr:
2. Vegetation must reach 40% density;
3. Vegetation diversity is as specified in Appendix D to Appendix A to the Updated Tailings Cover
Design Report, i.e., to contain the following:
a. Western wheatgrass, variety Arriba (Pascopyrum smithii)
b. Bluebunch wheatgrass, variety Goldar (Pseudoroegneria spicata)
c. Slender wheatgrass, variety San Luis (Elymus trachycaulus)
d. Streambank wheatgrass, variety Sodar (Elymus lanceolatus ssp. psammophilus)
e. Pubescent wheatgrass, variety Luna (Thinopyrum intermedium ssp. barbulatum)
f. Indian ricegrass, variety Paloma (Achnatherum hymenoides)
g. Sandberg bluegrass, variety Canbar (Poa secunda)
10 SCA 111C.7
11 SCA ¶4.(b)
Review Memorandum, Project L-2016-93, Reclamation Cover Test Monitoring
June 15, 2021
Page 5
h. Sheep fescue, variety Covar (Festuca ovina)
i. Squirreltail, variety Toe Jam Creek (Elymus elymoides)
j. Blue grama, variety Hachita (Bouteloua gracilis)
k. Galleta, variety Viva
1. Common yarrow, no variety (Achillea millefolium)
m. White sage, variety Summit (Artemisia ludoviciana)
n. Fourwing saltbush, variety Wytana (Atriplex canescens)
o. Rubber rabbitbrush, no variety (Ericameria nauseosus).
Unfortunately, we are in a drought, which complicates evaluation of all three criteria. Without
precipitation, the percolation rate might be controlled by evaporation preventing the formation of a
driving percolation front that might be present during wetter years. Plants in dormancy often will not be
counted, leading to underestimation of diversity and density values.
Results
Water Balance (Percolation Rate)
Table 1, on p. 3.1 of the Report, presents a percolation rate of 0.9 mm over the 2020 monitoring year,
with the text following the table making the claim that this is proof of meeting the percolation rate
standard of 2.3 mm/yr. However, precipitation was 128 mm versus an average expectation of 355 mm.
Of the 128 mm the test cell received, none was recorded as runoff Change in storage was recorded as -
63 mm. With meager precipitation, it is difficult to have confidence in a conclusion that the cover is
responsible for the low percolation values recorded.
Given the above analysis, the Division should continue evaluating the water balance to see whether a
wet year or two produce markedly differing results.
Vegetation Density
Appendix L, Section L.4.2 requires vegetation density to reach and be maintained at 40%.
The Report provides data from two site visits by Cedar Creek Associates, Inc. to evaluate the status of
plant development. The inspections results are summarized in Table 1, below.
Diac oli :\sscsmcrit ii vc . Vegetation Rock littcr Raft'
•( iroubd• • Pcreimial.,
1
Annuals
May 27, 2020 73.7 0.6 14.7 11.0 73.3 0.4
September 15, 2020 10.1 3.1 71.5 15.4 5.8 4.3
Table 1: Percent coverage during 2020 Primary Test Section inspections by Cedar Creek Associates
Review Memorandum, Project L-2016-93, Reclamation Cover Test Monitoring
June 15, 2021
Page 6
Table 1 presents values from the Annual Report. 2020 was a dry year throughout, with the drought
worsening as the year progressed. Table 1 presents evidence that the makeup of the active vegetative
cover made a significant transformation. Note that perennials dominate in the Spring, presumably
because of an abundance of water from snow melt. In the fall, the situation is reversed, with annuals
increasing as the perennials go dormant. The Primary Test Section did not achieve the 40 percent
vegetation target during the reporting period. While no conclusion can be drawn until the end of the
five-year study period, after three years of growth, one might expect more growth in a successful cover.
Vegetation Diversity
Table 2, below contains a summary of seeded vegetation species observed during the two visits made by
Cedar Creek Associates, Inc. to evaluate the status of plant development. Not included in the table but
noted by Cedar Creek Associates in their report were instances of Russian Thistle (Salsola tragus) and
Cheatgrass (Bromus tectorum) which do mot appear in the target seed mix.
I attended the surveys when these counts were made. Some seeded species were noted that did not
appear in the counts due to the techniques used; however, the numbers of these plants were very small.
The methodology used to perform the counts is designed to produce a statistically representative
summary of the conditions, and I believe this was achieved.
Table 2 shows that during the Spring survey, Squirreltail exceeded 90 percent of the observed
vegetation; in the Fall, Fourwing saltbrush exceeded over 60 percent of the cover. From this observation
it appears that the probability of achieving the plant diversity target of any one plant species providing
no more than 40 percent of the cover presene2 will be difficult to attain. In both surveys, only two
seeded species were noted. The two additional non-seeded species noted do not materially change these
percentages, so I have not considered them at this point. If the non-seeded species are native or adapted
to the area and are desirable additions, they can be counted toward acceptance at the end of the test
period.13
12 Appendix D,
13 Appendix D,
Review Memorandum, Project L-2016-93, Reclamation Cover Test Monitoring
June 15, 2021
Page 7
r Plant -,pcLit2,, Splin,t,1 Counts J \utuinn Counts
Grasses
Western wheatgrass, variety Arriba
(Pascopyrum smithii)
Bluebunch wheatgrass, variety Goldar
(Pseudoroegneria spicata)
Slender wheatgrass, variety San Luis
(Elymus trachycaulus)
Streambank wheatgrass, variety Sodar
(Elymus lanceolatus ssp. psammophilus)
Pubescent wheatgrass, variety Luna
(Thinopyrum intermedium ssp. barbulatum)
Indian ricegrass, variety Paloma
(Achnatherum hymenoides)
Sandberg bluegrass, variety Canbar
(Poa secunda)
Sheep fescue, variety Covar
(Festuca ovina)
Squirreltail, variety Toe Jam Creek
(Elymus elymoides) 1075 36
Blue grama, variety Hachita
(Bouteloua gracilis)
Galleta, variety Viva
(Hilaria jamesii)
Forbs
Common yarrow, no variety
(Achillea millefolium)
White sage, variety Summit
(Artemisia ludoviciana)
Shrubs
Fourwing saltbush, variety Wytana
(Atriplex canescens) 25 51
Rubber rabbitbrush, no variety
(Ericameria nauseosus)
Table 2: Counts of seeded species noted during the 2020 Primary Test Section inspections by Cedar Creek Associates
Additional Data Collection
EFR has recognized that the vegetation on the test sections likely will not meet criteria spelled out in the
SCA. Therefore, EFR has installed an additional test section adjacent to the Supplemental Test Section
specifically to seek answers to two questions: 14
14 2021 02 18 Letter from EFR to Ty Howard dated February 18, 2021, DRC-2021-002241.
Review Memorandum, Project L-2016-93, Reclamation Cover Test Monitoring
June 15, 2021
Page 8
1. Why has Squirreltail dominated on the Primary Test Section, and can adjusting the seed mix or
other actions help address this issue?
2. Why has the vegetation developed so poorly on the Supplemental Test Section?
The Division responded to the request to build the Second Supplemental Test Section noting that the
additional construction was not contemplated in the SCA. The Division took an interested posture
without approving the effort in order to keep the SCA and the process it spells out whole while still
acknowledging the potential benefit of the additional study to a modeling effort following conclusion of
the cover test to demonstrate that notwithstanding the failure to meet vegetation benchmarks the ET
cover will still provide the desired protection from infiltration.15
Summary
EFR desires to demonstrating the efficacy of an ET cover to complete decommissioning of the tailings
impoundments at the White Mesa Uranium Mill. A testing protocol has been implemented and test
sections installed to demonstrate the effectiveness of the ET cover concept in the climate prevailing at
the mill. The testing and monitoring protocols as well as percolation, plant diversity and plant density
benchmarks appear in the SCA. It appears, one year into the active testing period that the plant diversity
and density targets will not be met. Recognizing this, EFR has constructed an additional Supplemental
Test Section to gather additional data for model input to demonstrate that the ET cover can provide the
desired protection without meeting the stipulated plant density and diversity requirements.
15 2021 02 26 Division Response Letter dated February 26, 2021, DRC-2021-002332.