FIFTH FIVE-YEAR REVIEW REPORT FOR
UNITED NUCLEAR CORPORATION CHURCH ROCK SUPERFUND SITE
MCKINLEY COUNTY, NEW MEXICO
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FIFTH FIVE-YEAR REVIEW REPORT
UNITED NUCLEAR CORPORATION SUPERFUND SITE
EPA ID#: NMD030443303
MCKINLEY COUNTY, NEW MEXICO
This memorandum documents the U.S. Environmental Protection Agency's (EPA) performance, determinations,
and approval of the United Nuclear Corporation (UNC) Superfund Site (Site) Fifth Five-Year Review (FYR)
under Section 121(c) of the Comprehensive Environmental Response, Compensation, and Liability Act
(CERCLA), 42 U.S. Code Section 9621(c), as provided in the attached Fifth FYR Report. The Site is located in
McKinley County, New Mexico.
Summary of the Fifth Five-Year Review Report
The Site was listed on the National Priorities List (NPL) on September 9, 1983. The Remedial Investigation and
the Feasibility Study were completed in August 1988. The Record of Decision ("ROD") for the Site's first
operable unit1 ("OU1") was signed on September 30, 1988. Site cleanu under the OU1 ROD was completed and
documented in the Preliminary Close-out Report; which was signed on September 28, 1998.
This is the Fifth FYR of the Site. The purpose of a five-year review is to evaluate the implementation and
performance of a remedy in order to determine if the remedy is or will be protective of human health and the
environment. The triggering action for this review was the signing of the Fourth FYR report on September 27,
2013.
The Site is located 17 miles northeast of Gallup and on the southern border of the Navajo Nation. The Site is
comprised of the former ore processing mill facilities and a byproduct material (tailings) disposal area (hereinafter
the Tailings Disposal Area or TDA). The Tailings Disposal Area is comprised of three covered tailings
containment cells and two covered borrow pits.
At the Site, there are two agencies with overlapping jurisdiction—EPA and the U.S. Nuclear Regulatory
Commission (NRC). As stated in a 1988 Memorandum of Understanding (MOU) between EPA and NRC, NRC
assumed the role of lead regulatory agency for the Tailings Disposal Area reclamation and for the surface area
closure activities at the Site. At the same time, acting under the 1988 OU1 ROD, EPA developed and
implemented its own Site action requirements for ground water contamination outside of the Tailings Disposal
Area, in accordance with CERCLA and the National Oil and Hazardous Substances Pollution Contingency Plan
(NCP).
To summarize, until recently, NRC generally addressed the surface of the Site and the TDA, while EPA addressed
ground water and reviewed and commented on NRC action. On September 29, 2013, however, EPA issued
another Site ROD, calling for the disposal of waste from the Northeast Church Rock Mine Site (NECR Site), at
the United Nuclear Corporation Superfund Site, which is separate from the NECR Site. EPA refers to this waste
disposal action as Operable Unit 2 (OU2) or the Surface Soil Operable Unit. To complete the OU2 remedy, EPA
will be coordinating with NRC. In fact, EPA's implementation of the OU2 remedy is contingent.on the NRC
approval of a license amendment for the Site Tailings Disposal Area."
UNC is the primary responsible party for both the United Nuclear Corporation Site and the NECR Site. In
September 1997, UNC became a wholly-owned indirect subsidiary of the General Electric Company (GE).
' Operable unit means a discrete action that comprises an incremental step toward comprehensively addressing Superfund site
problems. The cleanup of a Superfund site can be divided into a number of operable units, depending on the complexity of
the problems associated with the site. 40 CFR § 300.5. In September 1983, the ROD was not referred to as the OUI ROD,
because it was not until 2013 that EPA decided to have more than one operable unit at the Site.
UNC Church Rock Uranium Mill Superfund Site Fifth Five-Year Review
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Collectively these parties are referred to in this FYR as "UNC/GE." UNC/GE have been working cooperatively
with EPA at the Site under an EPA administrative order for GUI. Under a separate administrative order on
consent, UNC/GE have been developing a Remedial Design for the implementation of the remedy under the OU2
ROD.
The recommendations from the 2013 FYR, along with a description, of the actions that have been taken in
response to those recommendations, and a description of the outcome of those actions are presented in Section 3.0
of this 2018 FYR.
Environmental Indicators
Human. Exposure Status: Current Human Exposure Controlled
Contaminated Ground Water Status: Contaminated Ground Water Migration Not Under Control.
Site-Wide Ready for Reuse: No
Actions Needed
The following actions should be taken for the remedy to be protective in the long term:
• Determine if changes in Applicable or Relevant and Appropriate Requirements (ARARs), MCLs in
particular, warrant a change in Remediation Goals for the remedy to remain protective.
• Evaluate the current extraction pumping in Zone 3 to determine whether it is effective at controlling
contaminant migration from the Site. In particular, the upgradient well series (i.e., RW-series) should be
evaluated to determine whether it is drawing in background water (i.e., water that came from
contaminated mine discharge, but that was not contaminated by tailings from the UNC mill) from the
west.
. • Continue efforts to minimize northward advancement of the Zone 3 ground water that has been impacted
by contaminants that seeped from Site tailings. These efforts should forestall contamination of aquifers
underlying Navajo land where drinking water wells may be installed in the future. As part of these efforts,
where practicable, extraction of contaminated ground water from Zone 3 should be continued in the
northernmost extraction wells. These northern wells are located at the leading edge of the ground water
that has been impacted by contaminants that seeped from Site, tailings. Evaluate expanded use of Natural
Attenuation.
• Renew efforts with stakeholders (e.g., the Navajo Nation and local residents) to establish Institutional .
Controls (ICs) that will restrict the use of contaminated ground water on Navajo, Tribal Trust, and Indian
Allotment lands (and unrestricted fee lands, if any) in all three hydrostratigraphic units.
Determination
I have determined that the remedy for the Site is currently protective in the short term. This five-year review
report specifies the actions that need to be taken for the remedy to be protective in the long term
t:
Ci
Director, Superfund Division
U.S. Environmental Protection Agency Region 6
UNC Church Rock Uranium Mill Superfund Site
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CONCURRENCES
FIFTH FIVE-YEAR REVIEW REPORT
UNITED NUCLEAR CORPORATON CHURCH ROCK SUPERFUND SITE
EPA ID#: NMD030443303
MCKINLEY COUNTY, NEW MEXICO
Jarfet Brooks
Remedial Project Manager
1fijzotf
Date
Blake Atkins
Chief, LA/OK/NM Remedial Section
Date
i C. Meyer
ifef, Superfund (^hiedial Branch
stello
up Leader, Office of Regional Counsel
Mark A. Peycke
Chief, Superfund Effanch, Office of Regional Counsel
iMia
Date
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Sate
A/'
. Date
Pamela Phillips
Deputy Director, Superfund Division
Wilt*
Date
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ISSUES/RECOMMENDATIONS
Issues and Recommendations Identified in the Five-Year Review:
OU(s): 1
Issue Category: Other
Issue: MCLs for certain contaminants of concern on the Site have changed, and these
changed MCLs are applicable or relevant and appropriate requirements (ARARs) for the
Site. EPA's policy regarding newly promulgated or modified environmental requirements
that are promulgated or modified after a ROD is signed is that EPA will not reopen the
remedy selection decision made in the ROD unless the new or modified requirement calls
into question the protectiveness of the selected remedy. EPA believes that it is necessary
to "freeze ARARs" when the ROD is signed. To do otherwise would disrupt CERCLA
cleanups, whether the remedy is in design, construction, or in remedial action. Each of
these stages represents significant time and financial investments in a particular remedy.
Recommendation:
Determine if the changes in MCLs warrant a change in Remediation Goals for the remedy
to remain protective.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party Responsible
Oversight
Party/Support
Agency
Milestone Date
No
Yes
EPA
EPA/State
6/30/2020 .
OU(s): I
Issue Category: Remedy Performance
Issue: The effectiveness of the Zone 3 O&M activities in controlling contaminant
migration from the Site needs to be assessed and adjusted accordingly since mine
discharge water may be drawing into the Zone 3 pumping wells.
Recommendation:
Evaluate the current extraction pumping in Zone 3, to determine whether it is effective at
controlling contaminant migration from the Site. In particular, the upgradient well series
(i.e., RW-series) should be evaluated to determine whether it is drawing in background
water (i.e., water that was contaminated mine discharge, but that was not contaminated by
tailings from the UNC mill) from the west.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party Responsible
Oversight
Party/Support
Agency
Milestone Date
No
Yes
PRP
EPA/State
1/31/2019
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OU(s): 1
Issue Category: Remedy Performance
Issue: Current pumping will reach a point where an extraction well will not be able to
withdraw water from the Zone 3 hydrostratigraphic unit. At this point in time, the Zone 3
contaminated water will still migrate northward toward the Navajo Reservation.
Recommendation:
Continue efforts to minimize northward advancement of the Zone 3 ground water that has
been impacted by contaminants that seeped from Site tailings. These efforts should
forestall contamination of aquifers underlying Navajo land where drinking water wells
may be installed in the future. As part of these efforts, where practicable, extraction of
contaminated ground water from Zone 3 should be continued in the northernmost
extraction wells. These northern wells are located at the leading edge of the ground water
that has been impacted by contaminants that seeped from Site tailings. Evaluate expanded
use of Natural attenuation.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party Responsible
Oversight
Party/Support
Agency
Milestone Date
No ¦
Yes .
PRP
EPA/State
1/31/2019
OU(s): 1
Issue Category: Institutional Controls
Issue: Although no Navajo are currently using ground water that is contaminated with
contaminants of concern (COCs) from the Site, there is a potential for water supply wells
to be installed in areas that may become impacted with hazardous substances.
Recommendation:
Renew efforts with stakeholders (e.g., the Navajo Nation and local residents) to establish
Institutional Controls (ICs) that will restrict the use of contaminated ground water on
Navajo, Tribal Trust, and Indian Allotment lands (and unrestricted fee lands, if any) in all
three hydrostratigraphic units.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party Responsible
Oversight
Party/Support
Agency
Milestone Date
No
Yes
PRP
EPA/State
6/30/2019 .
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Table of Contents
LIST OF ABBREVIATIONS & ACRONYMS . xi
i. introduction .• : 1
Site Background ; 1
FIFTH FIVE-YEAR REVIEW SUMMARY FORM : 3
II. RESPONSE ACTION SUMMARY 4
Basis for Taking Action 4
Contaminants of Concern 4
Response Actions 4
Selected Remedy : 5
Operable Unit 1 ...5
. Operable Unit 2 ; .6
Status of Implementation 6
OU1 - Ground Water Remedial Actions 6
Institutional Controls 7
Systems Operations/Operation & Maintenance 8
OU1 - Ground Water Remedial System Operation & Maintenance 8
III. PROGRESS.SINCE THE LAST REVIEW 9
IV. FIVE-YEAR REVIEW PROCESS 13
Community Notification, Involvement & Site Interviews . 13
Data Review 14
Southwest Alluvium !. 15
Zone 3 ¦. ! 16
Zone 1 17
Site Inspection 18
V. TECHNICAL ASSESSMENT ! 19
QUESTION A: Is the remedy functioning as intended by the decision documents? 19
QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels, and remedial action objectives
(RAOs) used at the time of the remedy selection still valid? 20
New, Revised, Promulgated or Enacted Standards since the 1988 ROD 20
QUESTION C: Has any other information come to light that could call into question the protectiveness of the
remedy? ;....21
VI. ISSUES/RECOMMENDATIONS ! 22
VII. PROTECTIVENESS STATEMENT 24
VIII. NEXT REVIEW ;.. 24
TABLES
Table 1 1988 ROD ARARs for OU1 and New, Revised, Promulgated or Enacted Standards since the
1988 ROD
Table 2 1988 ROD Remediation Goals and Contaminants for each Hydrostratigraphic Unit
Table 3 1988 ROD Remediation Goals Compared to Proposed Cleanup Levels
Table 4 Protectiveness Determinations and Statements from the 2013 Five-Year Review Report
Table 5 Status of Recommendations from the 2013 Five-Year Review Report.
Table 6 Detected Constituents in Southwest Alluvium, October 2017
Table 7 Detected Constituents in Zone 3, October 2017
Table 8 Detected Constituents in Zone 1, October 2017
Table 9 SWA Proposed Background Threshold Value Cleanup Levels based on UPL95 Summary
Comparisons
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Table 10 Zone 3 Proposed Background Threshold Value Cleanup Levels based on UPL95 Summary
Comparisons
Table 11 Zone 1 Proposed Background Threshold Value Cleanup Levels based on UPL95 Summary
Comparisons . 1
FIGURES
Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9a
Figure 9b
- Figure 10
Figure 11
Figure 12
Figure 13
Figure 14
Figure 15
Figure 16
Figure 17
Site Location Map
Site Layout
Extent of Seepage-Impacted Ground Water, October 2017
Southwest Alluvium Potentiometric Map, October 2017
Southwest Alluvium Saturated Thickness Map, October 2017
Southwest Alluvium Water Levels, 1989-2017
Southwest Alluvium Sulfate Concentrations, 1989-2017
Southwest Alluvium Bicarbonate Isoconcentration Map, October 2017
Uranium Concentrations in Southwest Alluvium Wells (509 D and GW 3)
Uranium Concentrations in Southwest Alluvium Wells
Zone 3 Potentiometric Surface Map, October 2017
Effects of Past and Current Pumping to Dewater Zone 3
Zone 3 Approximate Extent of Seepage-Impacted Ground Water, October 2017
Zone 3 Uranium, Vanadium, and Radionuclides Concentrations, 1989-2017
Zone 3 Uranium Isoconcentration Maps, October 2017
Zone 1 Potentiometric Surface Map, October 2017
Zone 1 Extent of Seepage Impacts, October 2017
Zone 3 Proposed Sentinel Monitoring Well Locations, October 2017
APPENDICES
APPENDIX A
APPENDIX B
APPENDIX C
APPENDIX D
APPENDIX E
SITE INSPECTION CHECKLIST
SITE CHRONOLOGY
INTERVIEW RECORDS
DOCUMENTS REVIEWED
SITE PHOTOGRAPHS
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LIST OF ABBREVIATIONS & ACRONYMS
AOC Administrative Order on Consent
amsl Above mean sea level
ARAR Applicable or Relevant and Appropriate Requirement
BTVs Background Threshold Values
CERCLA Comprehensive Environmental Response, Compensation, and Liability Act
' COC Contaminant of Concern
DOE United States Department of Energy
EPA United States Environmental Protection Agency
FYR Five-Year Review
gpm Gallons per minute
GE General Electric Company
GWPS Ground Water Protection Standards
ICs Institutional Controls
License NRC's Source Materials License SUA-1475
mg/L Milligrams per Liter
MCL Maximum Contaminant Level
MCLG Maximum Contaminant Level Goal
MNA Monitored Natural Attenuation
MOU Memorandum of Understanding
NCP National Oil and Hazardous Substances Pollution Contingency Plan
NECR Northeast Church Rock Mine Site
NMED New Mexico Environment Department
NMWQCC New Mexico Water Quality Control Commission
NNEPA Navajo Nation Environmental Protection Agency
NPL . National Priorities List
NRC United States Nuclear Regulatory Commission
OU1 Ground Water Operable Unit
OU2 Surface Soil Operable Unit
O&M Operation and Maintenance
PRP Potentially Responsible Party
Quivira Quivira Mine Site
pCi/L pico Curies per Liter
RAO Remedial Action Objectives
RI/FS Remedial Investigation and Feasibility Study
ROD Record of Decision
SDWA Safe Drinking Water Act
SWA Southwest Alluvium
SWSFS Site-Wide Supplemental Feasibility Study
TBC To be considered
TDA Tailings Disposal Area
TDS Total Dissolved Solids
TI Technical impracticability
TTL Treatment Technology Action Level
TTHM Total Trihalomethane
UAO Unilateral Administrative Order
UMTRCA Uranium Mill Tailings Radiation Control Act
UNC United Nuclear Corporation
UPL95 Upper prediction limits at 95 percent confidence
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I. INTRODUCTION
The Site was listed on the National Priorities List (NPL) on September 9, 1983. The Remedial Investigation and
the Feasibility Study were completed in August 1988. The Record of Decision ("ROD") for the Site's first
operable unit2 ("OU1") was signed on September 30, 1988. Site cleanup under the OU1 ROD was completed and
documented in the Preliminary Close-out Report; which was signed on September 28, 1998.
The purpose of a five-year review is to evaluate the implementation and performance of a remedy in order to
determine if the remedy is or will be protective of human health and the environment.The methods, findings, and
conclusions of reviews are documented in five-year review reports such as this one. In addition, FYR reports
identify issues found during the review, if any, and document recommendations to address them. . .
The EPA is preparing this five-year review pursuant CERCLA Section 121, consistent with the NCP (40 CFR
Section 300.430(f)(4)(ii)), and considering EPA policy.
This is the Fifth FYR for the Site. The triggering action for this statutory review is the completion date of the
previous FYR on 09/17/2013. The FYR has been prepared because hazardous substances, pollutants, or
contaminants remain at the Site above levels that allow for unlimited use and unrestricted exposure.
The Site consists of two OUs, but only OU1, which addresses the ground water remedy, is discussed in the data
review and technical assessment sections of this FYR. OU2 is a surface soil operable unit that is currently in the
remedial design phase. As such, only a brief summary of the current activities for OU2 are presented.
The Site FYR was led by Ms. Janet Brooks, of the EPA, with support from Mr. Steve Jetter and Mr. Angelo
Ortelli, of the New Mexico Environment Department (NMED), Ground Water Quality Bureau, Superfund
Oversight Section. Participants for the Site inspection included Mr. Ricky Spitz, Project Manager and Contractor
on the UNC Church Rock Project (see Appendix A for the Site Inspection Checklist). Participants in the
interviews included members of the Coyote Canyon and Pinedale Chapter Houses of the Navajo Nation. The
UNC, the potentially responsible party (PRP), has been a wholly owned indirect subsidiary corporation of the
General Electric Company (GE). UNC/GE was notified of the initiation of the five-year review. The Navajo
Nation Environmental Protection Agency (NNEPA) was also notified of the initiation of the five-year review. The
review began on 9/17/2017. .
Site Background
The Site is located 17 miles northeast of Gallup, New Mexico and on the southern border of the Navajo Nation
(Figure 1). The Site includes a former ore processing mill and TDA, which cover about 25 and 100 acres,
respectively (Figure 2). Two former uranium mines are located within one mile of the Site. To the northwest of
the Site is the NECR uranium mine site, which supplied the uranium ore to the Site. To the north of the Site is the
Quivira Mine Site (Quivira) that was operated by Rio Algom (formerly Kerr-McGee and Quivira). The Quivira
mine consists of Church Rock 1 and Church Rock IE mine sites.
The Site was granted a radioactive materials license by the State of New Mexico in May 1977, and operated from
June 1977 to May 1982 (see Appendix B for the Site Chronology). The mill was designed to process 4,000 tons of
ore per day from the nearby NECR mine and extracted the uranium using conventional crushing, grinding, and
acid-leach solvent extraction methods. The milling of uranium ore produced an acid slurry of ground waste rock
and fluid (tailings) that was pumped to the tailings impoundments. An estimated 3.5 million tons of tailings were
2 Operable unit means a discrete action that comprises an incremental step toward comprehensively addressing Superfund site
problems. The cleanup of a Superfund site can be divided into a number of operable units, depending on the complexity of
the problems associated with the site. 40 CFR § 300.5. In September 1983, the ROD was not referred to as the OU1 ROD,
because it was not until 2013 that EPA decided to have more than one operable unit at the Site.
UNC Church Rock Uranium Mill Superfund Site Fifth Five-Year Review
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disposed in the tailings impoundments. These tailings impoundments were subdivided by dikes into three cells;
identified as the South Cell, Central Cell, and North Cell (Figure 2) (EPA, 1988). Details of the site operational
history have been summarized in N.A. Water Systems (2008d), and Site Annual Reports (e.g., Chester Engineers,
2017). Uranium milling activities ceased in 1982. The TDA achieved interim closure status in accordance with
UNC's NR.C Source Material License SUA-1475 (License) for radioactive material. Currently, activities at the
Site are limited to O&M of the ground water remedial program and maintenance of the interim tailings cover.
There are three types of ground water on the Site. Two types are manmade (anthropogenic) arid have been defined
in the 1988 ROD and subsequent Site documents. The two types of manmade water were: 1) the mine water
discharged from the NECR and Quivira mines; and 2) the UNC mill water that was used to process the ore and
slurried into the TDA. The third type of ground water was natural water already in the ground and not from the
mines or mill. The water that existed in the ground before mining is called "natural ground water" in the rest of
this report.
The Site has three hydrostratigraphic units3 of interest in the ground water OU: the Southwest Alluvium (SWA),
and the Zone 1 and Zone 3 sandstone units from the upper Gallup Formation. Detailed descriptions of these
hydrostratigraphic units are provided in the Site-Wide Supplemental Feasibility Study (SWSFS) Parts I and II
(Chester Engineers, 2011).
Based on more than 30 years of site data, the hydrostratigraphic units were not saturated in the Site vicinity prior
to the discharge of mine water to the Pipeline Arroyo (see Figure 2). From approximately 1969 to 1986, large
volumes of ground water were pumped from the nearby NECR and Quivira mines to dewater the underground
workings. The average rate of mine water discharge was approximately 3,000 gallons per minute (gpm). This
water was discharged to the local Pipeline Arroyo, which runs through the Site. A portion of the mine discharge
water infiltrated into the subsurface and significantly saturated the near-surface alluvium and Zone 1 and Zone 3
sandstones. As designated in the ROD (EPA, 1988c), this infiltrated water represents the "background" ground
water conditions for the Site..This "background" phrase has also been referred to as "post-mining/pre-tailings"
background water quality in various Site documents.
Ground water in the SWA flows to the southwest along Pipeline Arroyo. Ground water in Zones 1 and 3 flows to
the north to northeast. The source of the water in all three hydrostratigraphic zones (above 6700 ft above mean
seal level (amsl) in the case of Zone 1 and 3). is from mine discharge water infiltration. Water levels in all three
zones reached their highest levels between 1977 and 1986 and have been steadily declining since the mine water
discharge ceased in 1986.
Acidic tailings liquids were stored in the TDA, beginning in 1977, in accordance with the NRC License and
standard mill procedures at that time. Seepage from the tailings impacted the "background water" (i.e., the portion
of the mine discharge water that had infiltrated into the subsurface during the mining era and significantly
saturated the near-surface alluvium and Zone 1 and Zone 3 sandstones). Seepage impacts have been observed in
the alluvium to the west and southwest of the tailings impoundment in the SWA and in Zone 3 and Zone 1 to the
north, northeast and east of the impoundment (see, e.g., EPA, 1988c; and see Figure 3). The term "seepage-
impacted water" is defined as the acidic water that seeped from the UNC mill tailing impoundments, which
contains the COCs as identified in the 1988 ROD. The seepage-impacted water is distinctly different from the.
water that infiltrated from the mine discharge waters which constitute the "background water," and it is also
distinctly different from the natural ground water that exists in Section 36 in Zone 3 and Zone 1 at about elevation
6700 ft amsl.
3 A hydrostratigraphic unit is a section of a geologic formation that exhibits similar hydraulic properties. In this
report, the term "hydrostratigraphic unit" will be used instead of the term "aquifer", which is commonly used for
water supply.
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The suiTounding lands include the Navajo Nation, Tribal Trust Land, Indian Allotment Land, and UNC-owned
property. To the northwest and adjacent to the Site is the former NECR mine, an underground uranium mine which
was also operated by UNC. The NECR mine is currently subject to EPA response actions directed by EPA
Region 9. Under the removal action at NECR and under the UNC OU2 ROD, EPA has called for approximately
one million cubic yards of contaminated mine waste from the NECR mine to be disposed at the TDA at the United
Nuclear Superfund Site. EPA's implementation of the OU2 remedy is contingent on the NRC approval of a
license amendment for the Site TDA which comprises three covered tailing cells and two covered borrow pits.
The surrounding lands are sparsely populated and the primary land use near the site is grazing for sheep, cattle,
and horses.
FIFTH FIVE-YEAR REVIEW SUMMARY FORM
Site Name:
United Nuclear Corporation Church Rock Superfund Site
EPA ID:
NMD030443303
Region: 6
State: NM
City/County: Gallup/McKinley County
NPL Status: Final
Multiple OUs?
Yes
Has the site achieved construction completion? (yes for OU1)
but no for OU2 as reflected below.
No
Lead agency: EPA
Author name (Federal or State Project Manager): Janet Brooks, Remedial Project Manager
Author affiliation: EPA Region 6
Review period: 9/17/2017 - 9/17/2018
Date of site inspection: 10/31/2017
Type of review: Statutory
Review number: 5
Triggering action date: 9/17/2013
Due date (fiveyears after triggering action date): 9/17/2018
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II. RESPONSE ACTION SUMMARY
Basis for Taking Action
EPA listed the Site on the NPL of Superfund sites in September 1983 and conducted a Site Remedial
Investigation (RI) and Feasibility Study (FS) from 1984 through 1988. The RI report concluded that because of
the disposal of mill tailings, acidic tailings fluid containing radioactive and other chemical constituent
contaminants seeped downward beneath the TDA and impacted three water bearing zones of the underlying
ground water, including the SWA, and Zone 1 and Zone 3 of the Upper Gallup Sandstone Formation.
Contaminants of Concern
The OU1 COCs and cleanup levels identified in the 1988 ROD (see Table 1) were established based on the
following:
• Post-mining/pre-tailings background levels were established for iron, manganese, sulfate,
nitrate, and total dissolved solids (TDS). By "background" EPA means the subsurface water
that originated from the mine water discharge and infiltrated the hydrostratigraphic units at
the Site. This background water is distinctly different from the acidic water that seeped from
the tailings impoundments. Background concentration levels of a contaminant in ground
water are generally used as a benchmark for measuring whether cleanup methods are
successful.
EPA MCLs were selected as the cleanup levels for arsenic, barium, cadmium, chromium, lead,
mercury, selenium, silver, radium-226, radium-228, gross alpha and thorium-230. The 1988
ROD noted that the thorium-230 level is based on the gross alpha MCL.
• New Mexico Water Quality Control Commission (NM WQCC) standards were selected as the
cleanup levels for aluminum, cobalt, copper, molybdenum, nickel, zinc, chloride, and uranium-
238. NMWQCC standards and MCLs were the same for barium, cadmium, chromium, lead,
mercury and silver.
• Health based criteria were calculated using Reference Doses for antimony, beryllium, thallium,
and vanadium. A Reference Dose means an estimate (with uncertainty spanning perhaps an order
of magnitude) of a daily oral exposure for an acute duration (24 hours or less) to the human
population (including sensitive subgroups) that is likely to be without an appreciable risk of
deleterious effects during a lifetime.
Resources impacted by the contamination include the SWA and Zone 3 and Zone 1 ground water
hydrostratigraphic units. Nearby residents and livestock are not exposed to Site-related ground water
contamination at present because there are no domestic or livestock wells within close proximity to the Site. The
UNC production well on the Site is accessible only by Site management. Exposure to surface soils and tailings
through direct contact is controlled through requirements in the NRC License SUA-1475. Air emissions are also
controlled through the requirements of NRC License SUA-1475
Response Actions
Prior to the 1988 ROD, UNC undertook several actions under its NRC License. During that time, UNC/GE also
assisted in the development of the EPA Remedial Investigation and Feasibility Study (RI/FS). UNC also
undertook actions as required by the New Mexico Environmental Improvement Division (now NMED) to address
ground water concerns. UNC neutralized the acidic mill tailings by adding ammonia and lime to raise the pH
levels in the TDA. UNC also investigated the impact of the tailings seepage on ground water. UNC began ground
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water remediation in 1982. UNC installed and operated wells to extract tailings seepage. UNC extracted
neutralized water and discharged the neutralized water into the tailings disposal cells for evaporation.
Implementation of the processes for reclamation and ground water remediation under the NRC License began in
1986, when the NRC assumed mill site licensing responsibility from the State. UNC submitted a draft reclamation
plan to NRC in 1987, and the final plan was approved in March 1991.
Selected Remedy
The remedy selected in'EPA's 1988 ROD for OU1—the ground water operable unit—is the subject of this FYR
Report and includes the following six elements:
1. Implementation of a monitoring program to detect any increases in the areal extent, or concentration of
ground water contamination outside the tailings disposal area.
2. Operation of existing seepage extraction systems in the Upper Gallup aquifers!
3. Containment and removal of contaminated ground water in Zone 3 of the Upper Gallup Sandstone
utilizing existing and additional wells.
4. Containment and removal of contaminated ground water in SWA utilizing existing and additional wells.
5. Evaporation of ground water removed from aquifers using evaporation ponds supplemented with mist or
spray systems to enhance the rate of evaporation.
6. Implementation of a performance monitoring and evaluation program to determine water level and
contaminant reductions in each aquifer, and the extent and duration of pumping actually required outside
the tailings disposal area.
Based on the RI/FS, the RAOs established in the 1988 ROD for OU1, ground water remedy, included:
• Containment of down-gradient contaminant migration within each target area.
• Restoration of ground water down-gradient of the TDA, to the maximum extent practicable, to
meet the cleanup criteria.
Restoration of ground water at the TDA to a level that allows attainment of cleanup criteria at its
boundary.
The goal of the selected remedy for OU1 at the Site was to restore ground water outside the TDA to federal and
state standards, health based criteria, or background levels, to the maximum extent practicable, and to the extent
necessary to adequately protect public health and the environment. However, as stated in Appendix A of the
1988 ROD, it was recognized that cleanup levels may not be reached within a reasonable time period due to the
hydrogeologic characteristics of the aquifers.
The 1988 ROD identified remediation goals for the twenty-eight contaminants detected in Site ground water during
the remedial investigation. Of the 28 remediation goals, 19 are ARARs, four are health-based criteria and five are
background levels that were based on the mine water discharge {i.e., hydrostratigraphic water that originated from
mine water discharge, but which had not been impacted by contamination seeping from mill tailings), which is also
reffered to as "background water" or "post-mining/pre-tailings background water" in this FYR report. Table 2 lists
the Site contaminants identified in the 1988 ROD that exceed the established cleanup-levels and the
hydrostratigraphic units in which they were exceeded.
Operable Unit 1
The 1988 ROD did not provide a clear evaluation of the post-mining/pre-tailings background water quality
in establishing the Site cleanup standards. The COCs or cleanup levels for the Site were not specifically identified
in the 1988 ROD. UNC addressed cleanup levels in the UNC SWSFS Part I investigation report that included: 1)
a thorough review and update of the Site COCs based on screening with current federal MCLs, health based ,
criteria, background water quality; and 2) an update and recommendation for revision of the Site cleanup levels.
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Parts I and II of the SWSFS have been reviewed and accepted by the EPA but have not yet modified the COC list
and monitoring program.
The NRC has approved several revisions to License standards including changes to the COCs, and monitoring
programs recommended by UNC. EPA has discussed those revisions with the NRC but has not modified the
cleanup levels or remedy set forth in the 1988 ROD to be consistent with NRC revisions. Such consistency, where
appropriate, would help to integrate and coordinate the ground water and source control/surface reclamation
activities to achieve comprehensive reclamation and remediation of the Site. This sort of integration and
coordination is called for in the MOU between the EPA and the NRC.
The EPA plans to revise the background water levels, as appropriate, to make them a more accurate reflection of
the water that existed post-mining/pre-tailings now that the SWFS Parts I and II are complete. The SWFS Parts I
and II include a thorough and comprehensive review of the existing cleanup levels, an evaluation of newly
promulgated standards as potential new ARARs, and more recent health based toxicological information and
background water quality data. Since the 2013 FYR was completed, UNC has completed a working draft of Part
III of the SWSFS, including an analysis of remedial alternatives. A summary of this work is presented and
discussed in Section 3.0.
Operable Unit 2
EPA has not yet implemented the remedy for OU2, the Surface Soil Operable Unit, which is still in the Remedial
Design phase. EPA entered into a settlement agreement with UNC and GE and under that agreement, UNC/GE
agreed to develop a Remedial Design for the implementation of the remedy selected in the ROD. The Remedial
Design is subject to EPA's approval. The settlement agreement was documented in a 2015 EPA administrative
order on consent (AOC). Under the AOC, UNC/GE completed the Preliminary Design (30%) in late 2016, and
UNC/GE submitted a Draft Pre-Final Design (95%) to EPA for review and comment in October 2017. The OU2
remedy selected in EPA's 2013 ROD for OU2—the surface soil remedy—addresses contaminated surface and
subsurface soil from the nearby NECR mine. The Selected Remedy described in the 2013 ROD does not
address contaminated ground water at the Site which is being remediated under the separate 1988 ROD
for OU1, as described above.
Status of Implementation
The 1988 MOU between EPA Region 6 and Region IV of the NRC indicated that these two regions understood
that NRC would exercise its authority over surface reclamation and source control. The 1988 ROD stated that,
"...Upon approval of a final reclamation plan, both ground water and source control/surface reclamation remedial
actions will be integrated and coordinated to achieve comprehensive reclamation and remediation of the Site"
(1988 ROD, p. 41').
Source control measures regulated by the NRC were constructed primarily to effectively minimize infiltration,
seepage, and mobilization of contaminants from the tailings. The source control measures implemented in the
NRC license included regrading and recontouring the tailings, placing a low permeability compacted soil cover
over the regraded tailings, and constructing drainage swales on and around the reclaimed impoundments. The
tailings impoundment covers consist of an interim cover of compacted soil, followed by the final cover of
compacted soil and rock. The interim and final covers act as a radon barrier and for erosion protection.
QUI - Ground Water Remedial Actions
UNC implemented the remedial systems at the Site as required by the 1988 ROD, which operated as intended for
a period of time. As UNC has dewatered Site areas, extraction well efficiency declined and the wells were
decommissioned in accordance with decommissioning criteria set forth in the NRC license. Currently, of the six
elements identified in the 1988 ROD, elements 1, 3, and 6 remain active, elements 2 and 4 are inactive, and
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element 5 is partially active - the evaporation ponds are in use but the spray systems are inactive. {See supra p. 5
{Selected Remedy) for a numbered list of the OU1 ROD elements.) The tailings seepage mound has dissipated
due to the pumping from the three hydrostratigraphic units (only Zone 3 is still pumping water) and minimal
natural recharge from precipitation. Efforts to restore ground water quality outside the TDA to established
standards, criteria, and background levels by UNC/GE has potentially reached the maximum extent practicable,,
according to the limited ability to pump from the Zone 3 wells. Operational results from the performance
monitoring program gathered by UNC/GE indicate a significant reduction in the saturated thickness of water in all
three hydrostratigraphic units which severely limits the ability to extract impacted ground water.
Historically, all the ground water produced from all extraction wells on the Site was placed into two five-acre
ponds (Figure 2) where it evaporated. The water was then pumped through a spray evaporation system installed
on the surface of the regraded and covered tailings. An evaporation mist system constructed on the interior berm,
between the two evaporation ponds, was designed to enhance the disposal of the extracted water during the
summer months. During the winter months, a small amount of water accumulates in the evaporation ponds from
winter precipitation. The evaporation mist system ceased operation in 2001, when the rate of ground water
extraction declined significantly (only Zone 3 has been pumped since 2001). Currently, due to the lack of a
sufficient volume of water being pumped from the Zone 3 hydrostratigraphic unit, UNC/GE is supplementing the
volume of water in the evaporation ponds with water pumped from the on-site production well. This water is
needed to keep the evaporation liner saturated.
The SWA remedial system (see Figure 4) was temporarily shut down by EPA in 2001 to conduct a natural
attenuation test. Since 2001, the SWA remedial system has remained idle, ile., water has not been pumped from
any of the SWA wells. Performance monitoring is ongoing. Monitored natural attenuation (MNA) has been
effective in addressing the residual contaminant concentrations in the SWA.
The Zone 3 (see Figure 10) remedial system continued operating throughout this FYR period. The ground water
extraction system for Zone 3 uses six wells along the seepage-impacted front that is designed to capture and slow
migration of the ground water in Zone 3 that has been contaminated by water seeping from the disposal cells on
the Site. UNC has adjusted the pumping regime along the NW-series extraction wells (see Figure 10) since 2009
to: (1) minimize the withdrawal of background water originated from the mine water discharge; (2) limit the
tendency for seepage-impacted water from the disposal cells to be drawn westward or northward at the northern
portion of Zone 3; and (3) improve the capture of seepage-impacted water from the pumping wells. The goal is to
strike the best balance between containing the seepage-impacted water while minimizing its transport to the more
thickly saturated, but non-seepage-impacted parts of Zone 3.
The Zone 1 (see Figure 15) remedial system was decommissioned by NRC in July 1999. Performance monitoring
is ongoing.
Institutional Controls
ICs are non-engineered instruments such as administrative and legal controls that help minimize the potential for
human exposure to contamination and/or protect the integrity of the remedy selected by EPA for a Superfund site.
The 1988 ROD did not formally establish any ICs; however, certain enforcement documents, governmental
controls, and informational controls are in place. Informational controls such as signs are posted near the TDA.
In 1989, EPA issued a unilateral administrative order (UAO) to UNC. The UAO required UNC to undertake the
ground water remediation required by EPA's OU1 ROD. In addition, the NRC's Site Source Materials License
No. SUA-1475 remains in effect. As part of the license, NRC requires that UNC manage the Site to prevent
contaminant exposure, including exposure to those contaminants in the ground water.' .
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There are currently no ICs restricting the use of ground water impacted by contaminated seepage from the tailings
cells that has migrated beyond the boundary of the NRC Licensed Site. There are also no ICs establishing land
use restrictions in place in the area impacted by contaminated water seeping from the tailing cells.
Systems Operations/Operation <6 Maintenance
QUI - Ground Water Remedial System Operation & Maintenance
Ground Water O&M is required by EPA's 1988 ROD, which addresses Site ground water, and by EPA's 1989
UAO to UNC, which requires UNC to implement the ground water remedy in the OU1 ROD. The required O&M
activities include:
• Operation, maintenance, and monitoring of the ground water extraction wells and associated piping.
• Maintenance of interim covers and the final radon barrier on the tailings disposal cells.
•. Operation and maintenance of the evaporation ponds, misters, and water cannons.
• Maintenance and sampling of ground water monitoring wells.
• Maintenance of fences and gates.
Pumping in the SWA was discontinued in 2001, due to the effectiveness of natural attenuation. Pumping in-Zone 1
was discontinued, due to low productivity of the wells (combined pumping rate from the three wells is 0.64 gpm).
UNC/GE continues ground water extraction in Zone 3 using wells along the seepage-impacted front (see Figure 10
for well locations). GE/UNC continues to monitor ground water in all hydrostratigraphic units.
The Zone 3 extraction wells are operational; however, they require frequent maintenance and pumping rates
continue to decrease to less than 0.3 gpm/well in 2017. Combined flows from the Zone 3 wells have decreased
from 1.9 gpm in 2014 to 1.18 gpm in 2017, and the annual volumes extracted have decreased from 1,097,483
gallons in 2013 to 619,000 gallons in 2017 (see Annual Monitoring Reports, Table 8). UNC/GE continues to
actively promote the extraction of water by repairing the six extraction pumps as needed.
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III. PROGRESS SINCE THE LAST REVIEW
This section includes the protectiveness determinations and statements from the last five-year review (EPA 2013),
as well as the recommendations from the last five-year review and the current status of those recommendations.
Table 4 - Protectiveness Determinations and Statements from the 2013 FYR
Oil #
Protectiveness
Determination
Protectiveness Statement
1
Short-term
Protective
The remedy at OU1 (the final source remedy) currently protects human health and the
environment in the short term. Actions taken have minimized potential human exposures to
contaminants found in the ground water and reduced the potential for the repository tailings
to act as a source of ground water contamination.
For the remedy to be protective in the long term, the following actions need to be taken:
1. Evaluate and revise the estimated background contaminant levels at the Site and
reevaluate Site cleanup standards (i.e., remediation goals) through theNCP decision-
making process.
2. Complete the ongoing SWSFS Part HI to develop and analyze remedial alternatives.
3. Continue the experimental efforts to create a subsurface hydraulic barrier in Zone
3 to slow'down and contain the migration of the seepage-impacted water in the
northern subsurface area. ¦
4. Determine whether the SWA extraction wells have provided improvement in
ground water quality with respect to uranium contamination when compared to
Natural Attenuation.
5. Evaluate the use of various mechanism(s) of Natural Attenuation in the SWA for
uranium as well as for other COCs in all hydrostratigraphic zones as part of the
ongoing remediation effort to attain cleanup standards.
6. Renew efforts to establish ICs that will help, protect human health by
restricting the use of contaminated ground water on affected Navajo Nation,
Tribal Trust, and Indian Allotment lands.
7. Evaluate whether a Technical Impracticability (TI) waiver is appropriate for the
ARARs related to sulfate and TDS. This evaluation would be done as part of the
ongoing SWSFS, Part III.
8. Evaluate the anthropogenic origin and the transient nature of the artificially created
ground water hydrostratigraphic units impact on future EPA ground water
decision making.
2
Will be
Protective
The surface soil operable unit (OU2) remedy described in the 2013 OU2 ROD, which provides
for the disposal ofNECR mine waste at the Site TDA, is expected to be protective of human
health and the environment upon completion. At present [i.e., in 2013], remedial design
activities are underway which will adequately address all exposure pathways that could result
in unacceptable risks associated with OU2.
Sitewide
Short-term
Protective
The remedial action that has been taken to address ground water contamination at the Site and
the remedial action that has been taken to address contamination on the surface of the Site are
presently protective of human health and the environment and should remain protective in the
short term.
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Table 5 - Status of Recommendations from the 2013 FYR (Note: In many circumstances at Superfiind sites that
address contaminated ground water, "background" is essentially defined as the amount of a contaminant that is
present in the native ground water that is not due to local anthropogenic sources, such as a release. That is not what
"background" means in this FYR because at the Site, there is no native ground water (except at the northern
boundary of Section 36—not pertinent here). The Site hydrostratigraphic unit that was in place before the Site mill
operated was water pumped out of the mines located northwest of the mill. This mine discharge water was untreated
until 1975, and probably contained high concentrations of contaminants. After 1975, discharge water was allowed
to contain uranium concentrations of up to 2 milligrams per Liter (mg/L) under the provisions of the two mines'
NPDES permits. In EPA's 1988 OU1 ROD, the concentration of contaminants in this mine discharge water is
referred to as "background."- This FYR also refers to this contaminated water as "background." This makes sense
because there was no appreciable subsurface water at the Site (other than the Section 36 water) until this mine
discharge water came to the Site.
The "Background Threshold Value" (BTV), a term used in the following table, is a value that characterizes the
background dataset, i.e., non-seepage-irhpacted water. Contaminant concentrations ("values") found in water
samples taken from the subsurface that are below the BTV would be considered representative of "background"
subsurface water (i.e., the mine discharge water that came to be located in the subsurface hydrostratigraphic unit
at the Site); values above the BTV might be above background. The 95th percentile has been selected for this
evaluation to serve as the BTV. However, it should be recognized that by definition, 5% of all true "background"
subsurface water samples would be interpreted as above background using this BTV as a benchmark statistic. The
BTVs presented here are UPL95 values (95th percentile upper prediction limits), which represent not-to-exceed
values that are appropriate for compliance monitoring on a point-bypoint (i.e., well-by-well) basis (GE, 2012).
Note also that subsurface water described in this FYR as Tailings Seepage Water is water that became contaminated
because it entrained contaminants as it passed through the mill tailings piles created by the United Nuclear
Corporation mill on the Site.
ou#
Issue
Recommendations
Current
Status
Current Implementation
Status Description
(additional discussion
below table)
Completion
Date (if
applicable)
1
1. The 1988 ROD did not
provide a clear evaluation
of the post-mining/pre-
tailings background water
quality in establishing the
Site cleanup standards.
Evaluate and revise the
estimated background
contaminant levels at the
Site and reevaluate Site.
cleanup standards (i.e.,
remediation goals)
through the NCP
decision-making process.
Ongoing
NRC revised ground water
protection standards based
on updated Background
Threshold Values (BTVs)
for the Site. NRC approved
the BTVs in 2015. EPA
has not acted on the
proposed BTVs in a
decision document.
N/A
1
2. The ground water remedy
cannot attain the cleanup
levels within a reasonable
time frame because the
source of anthropogenic
recharge to the ground
water system is no longer
available and has resulted in
a significant loss of aquifer
saturated thicknesses.
Complete the ongoing
SWSFS Part III to
develop and analyze
remedial alternatives.
Ongoing
EPA Region 6 will stop'
work on the SWSFS Part
III determination until after
EPA Region 9 completes a
water quality investigation
of the NECR and Quivira
mines (see Data Review
section below).
Stop Work
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ou#
Issue
Recommendations
Current
Status
Current Implementation
Status Description
(additional discussion
below table)
Completion
Date (if
applicable)
1
3. The Zone 3 extraction
. well system cannot
hydraulically control the
migration of tailings
seepage-impacted water
northward toward and
eventually on to the Navajo
Nation lands.
Continue the
experimental efforts to
create a subsurface
hydraulic barrier in Zone
3 to slow down and
contain the migration of
the seepage-impacted
water in the northern
subsurface area.
Ongoing
The Zone 3 extraction
system has been declining
in performance due to the
decreasing amount of
water that is being
extracted; consequently,
active remedial operations
in Zone 3 are reaching the
limits of their
effectiveness.
N/A
1
4. The question still remains
as to whether or not the
operation of the extraction
system in the SWA is
effective for improving
ground water quality with
respect to uranium and
whether natural attenuation
can be relied,upon as part of.
the remedy to mitigate
tailings seepage impacts on
ground water.
Determine whether the
SWA extraction wells
have provided
improvement in ground
water quality with
respect to uranium
contamination when
compared to natural
attenuation.
Under
Discussion
The SWA extraction
system has remained idle
since 2001 due to only
sulfate and TDS migrating
out of the tailing cells.
TDS and sulfate are
secondary drinking water
standards, which are not
remediation goals at the
Site. Significantly, the
natural geochemistry of the
ground water appears to be
effective for improving
ground water quality with
respect to uranium
concentrations.
N/A
1
5. Uranium concentrations
in the SWA ground water
do not exceed the uranium
cleanup level of 5.0
milligrams per Liter (mg/1)
called for in the 1988 ROD.
However, they do exceed
the 2003 promulgated EPA
Safe Drinking Water. Act
' (SDWA) MCL for uranium
of 0.030 mg/1.
Evaluate the use of
various mechanism(s) of
natural attenuation in the
SWA for uranium as well
as for other COCs in all
hydrostratigraphic zones
as part of the ongoing
remediation effort to
attain cleanup standards.
Under
Discussion
UNC/GE submitted an
expanded list of proposed
BTVs in 2015, including
COCs addressed in the
1988 ROD. The updated
BTVs for each EPA-
regulated COC were
critically compared to
ARARs and the ROD
standards to propose
appropriate cleanup levels
for COCs. EPA has not
acted on the proposed
BTVs in a decision
document.
N/A
1
6. In light of the technical
difficulties of achieving Site
ground water cleanup levels
using engineering controls,
ICs may have to play a
larger role in protecting
human health at the Site.
Renew efforts to
establish ICs that will
help protect human
health by restricting the
use of contaminated
ground water on affected
Navajo Nation, Tribal
Trust, and Indian .
Allotment lands.
Under
Discussion
Efforts to discuss ICs with
the Navajo Nation have not
been renewed
01/31/2019
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ou#
Issue
Recommendations
Current
Status
Current Implementation
Status Description
(additional discussion
below table)
Completion
Date (if
applicable)
1
7. Sulfate and TDS
concentrations are not
dependent on continued
operation of extraction
systems in the hydro-
stratigraphic units at the
Site, but rather these
constituent concentrations
are controlled by natural
geochemical reactions,
primarily the chemical
equilibrium with gypsum
and/or anhydrite.
Evaluate whether a TI
waiver is appropriate for
the ARARs related to
sulfate and TDS. This
evaluation would be
done as part of the
ongoing SWSFS, Part
III.
Under
Discussion
Statistical evaluation of the
background sulfate and
TDS concentrations has
been completed. EPA has
not acted on the proposed
BTVs for sulfate and TDS.
N/A
1
8. Background water at the •
Site is not a natural water
source but instead an
anthropogenic artificial
aquifer created by mine
water effluent that was
pumped from the
Westwater Canyon Member
of the Morrison Formation,
which contains the uranium
ore body.
Evaluate the
anthropogenic origin and
the transient nature of the
artificially created
ground water aquifers
impact on future EPA
ground water decision
making.
Under
Discussion
LTNC/GE used statistical
analysis of water chemistry
from wells located outside
of the seepage-impacted
area to calculate BTVs
from the mine discharge
water that infiltrated the
subsurface prior to the mill
tailings seepage impact.
UNC/GE submitted an
expanded list of BTVs in
2015, including COCs
addressed in the 1988
ROD. The updated BTVs
for each EPA-regulated
COC were critically
compared to ARARs and
the ROD standards to
select appropriate .cleanup
levels. EPA has not acted
on the proposed BTVs in a
decision document
N/A
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IV. FIVE-YEAR REVIEW PROCESS
Community Notification, Involvement & Site Interviews
EPA published a public notice regarding the FYR in the Gallup Independent newspaper, on 11/1/2017. The
notice stated that there was a five-year review and invited the public to submit any comments to the U.S. EPA.
The notice also said that the results of the FYR will be described in the FYR report, which will be made available
at the following Site information repositories:
_ University of New Mexico - Gallup Zollinger Library
705 Guriey Avenue, Gallup, NM 87301
Navajo Nation Environmental Protection Agency Superfiind Office
Highway 264/43 Crest Road St. Michaels, AZ 86511.
(928) 871-6859/ (800)314-1846
During the FYR process, interviews were conducted with stakeholders, including UNC/GE, federal and tribal
agencies, residents and Chapter House officials to document any perceived problems or successes with the
remedy that has been implemented to date. Interview records are included in Appendix C. The results of these
interviews are summarized below.
Interview questionnaires were sent out to each regulatory stakeholder and to UNC/GE in October 2017.
Stakeholders included the NRC, U.S. Department of Energy (DOE) Office of Legacy Management, and the
Navajo Nation EPA. Only DOE and UNC/GE sent a response. In its response to the questionnaires, DOE
responded that its role in the Site is informal at this point but its purpose in the review process is "twofold, first to
ensure the intended end-state does not conflict with DOE future obligations under UMTRCA [Uranium Mill
Tailings Radiation Control Act]. Second is DOE-LM [DOE Legacy Management] has many years of experience
with cells such as the UMTRCA cell [i.e., the TDA cell at the Site] and can provide useful history, expertise and
experience. " In addition, DOE feels well informed, expects that the ground water remedy will be completed.and
require no monitoring under UMTRCA at the completion of the remedy, before NRC terminates the license and
transfers the property to DOE.
UNC/GE emphasized in their response to the questionnaire that the remedy has performed as expected with the
Zone 1 and SWA remedies being shut down since 1999 and 2001 respectively. UNC/GE stated that the Zone 3
remedy is reaching the limit of effectiveness as Zone 3 is dewatered. Additionally, UNG/GE states:
Migration of the Zone 3 plume has been slowed, but it will only cease to migrate when certain
natural hydraulic forces are balanced by the chemical reactions that are attenuating and restricting
the movement of the seepage-impacted water. At this point, continued downgradient migration
> can no longer be altered by using hydraulic modifications (i.e. pumping) due to the dip of the
geologic strata within which the groundwater moves.
Pumping from Zone 3 wells continues, albeit at a consistently declining yield. Groundwater
recovery from all Zone 3 pumping wells combined was about 2.3 gallons per minute (or about the
same as a garden hose turned on low) at the time of the last Five-year Review. It is now about 1.4 .
gpm. The proportion of seepage-impacted water recovered to background water recovered is
steadily shifting towards the latter. The groundwater recovery is rapidly meeting the limits of any
beneficial effect if it has not already reached that point.
In addition, in-person interviews were conducted at the Coyote Canyon and Pinedale Chapter Houses on the
Navajo Nation. On the Navajo Nation, Chapter House representatives presented the views of their respective
Houses. Individual Navajos were also interviewed. The primary concerns expressed by individuals and by the
Chapter Houses was the lack of site update information and regular communication from the regulatory agencies.
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They also expressed an interest in having more educational presentations, particularly at schools, to inform young
people about the Site.
Also, individuals and the Chapter Houses expressed concerns about windblown contamination that may have been
deposited off-site or onto trees that could then be used as firewood. To address these concerns regarding .
windblown contamination, on June 19, 2017, the EPA ASPECT airplane conducted radiological surveys over the
Site and the NECR and Quivira mines. Preliminary results did not indicate the presence of any off-site windblown
contamination.
EPA participates in monthly teleconferences with the local community and responds to any questions and
concerns raised by the community. The Site Community Involvement Plan was recently updated on May 18,
2018, and copies of the Community Involvement Plan were provided to the Red Water Pond Road Community
Association and to Coyote Canyon, Pinedale, Church Rock, Standing Rock and Nahodishgish Chapterhouses.
Data Review
Sampling events occur quarterly in all three hydrostratigraphic units. The data are reported semi-annually and an
annual report is prepared.
EPA has assessed remedy performance through a data review process (see Appendix D for Documents
Reviewed). Data reviewed includes ground water performance monitoring data collected over the five-year
review period covered in this report. Data review also included an evaluation of the historical Site ground water
concentrations of COCs identified in the ROD, where updated BTVs were calculated through statistical analysis
using Upper Prediction Limits at 95 percent confidence (UPL95) (see supra Table 5 introductory note regarding
"background" and Background Threshold Value)) . Tailings-seepage-impacted water affects three
hydrostratigraphic units - SWA, Zone 3, and Zone 1 (see Figure 3). Specific observations related to these
hydrostratigraphic units are discussed below.
GE/UNC submitted a working draft of the SWSFS Part III to EPA for comment on January 6, 2017 (Chester
Engineers, 2017a). A principal source of uranium for ground water in the SWA and Zone 3 was mine discharge
water that was permitted to contain uranium concentrations up to 2 milligrams per Liter (mg/L). This mine water
was discharged to Pipeline Arroyo from both the NECR and Quivira mines, which are located northwest of the
Site (see Figure 2), for approximately 17 years. Consequently, the hydrostratigraphic units are considered to be
artificially created ground water of anthropogenic origin with degraded water quality from the the time they were
discharged. That is, the hydrostratigraphic units are not naturally occurring, but were created when miners
pumped uranium contaminated water, from the mines into Pipeline Arroyo where it percolated into the subsurface.
Chester Engineers presented the following data from the working Draft SWSFS-Part II I.of the estimated
background water volumes (mine discharge water) compared to the seepage-impacted volumes:
Hydrostratigraphic Unit
¦ Background4 Water
Volume (gallons)
Seepage-Impacted Water (Oct
2015) (gallons)
Seepage-Impacted
Water/Background
Ratio (%)
SWA
17,831,613,510
140,451,966
0.788
Zone 3
701,624,000
11,274,873
1.6
Zone 1
2,161,720,000
9,360,781
0.433
EPA Region 9 will investigate the extent of the historic mine water discharge, i.e., the Background Water Volume
(in the above table) in the vicinity of the NECR and Quivira mines (EPA, 20.16). EPA Region 9 will begin their
water quality investigation after UNC/GE installs sentinel monitoring wells on the Navajo Nation. Installation of
4 See supra Table 5 introductory note regarding "background" and Background Threshold Value
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the sentinel monitoring wells is planned for Summer 2018. Due to the significant volume of water volume from
mine water discharge (21 billion gallons) that may be impacting the seepage-impacted water (161 million gallons)
EPA Region 6 believes that stopping work on the SWSFS Part III is warranted until EPA Region 9 determines the
extent of mine water discharge impact to the local water system in the vicinity of the Site. The remedial
alternatives presented in the working draft SWSFS Part III may be inappropriate, due to the significant impact to
the seepage-impacted water from the mine water discharge in the vicinity Of NECR and Quivira Mines.
. Site-wide ground water elevations have gradually declined since the OU1 remedy was constructed in 1989. A
trend toward decreasing water levels continued in each hydrostratigraphic unit on the Site, even after the ground
water extraction system operations ceased in the SWA and Zone 1 hydrostratigraphic units. The site-wide ground
water elevation decline is primarily due to cessation of mine water discharges into Pipeline Arroyo in 1986. The
mine water discharges in to the arroyo, prior to 1986, had infiltrated the subsurface and recharged the SWA, Zone
3, and Zone 1 hydrostratigraphic units during the mine dewatering operations.
Southwest Alluvium
The SWA potentiometric surface map for the October 2017 monitoring event (Figure 4) shows that, in the vicinity
of the Site, ground water flows to the southwest, along the Pipeline Arroyo. Ground water also flows eastward
beneath the northwestern part of the South Cell, reflecting the presence of a relatively high area (bulge) in the
bedrock surface that encompasses the "Nickpoint" along Pipeline Arroyo (Figure 4). Contours of saturated
thickness in the SWA'(Figure 5) during the UNC/GE October 2017 monitoring event indicated that the northern
portion of the ground water system, upgradient of the Nickpoint at well 0509 D (Figure 5), may have become
separated (i.e., ponded due to loss of hydraulic continuity) from the ground water to the south. A time-series plot
from January 1989 through January 2017 (Figure 6) shows the gradual decline in the SWA water level elevations.
EPA ended extraction well pumping in January 2001 to conduct a natural attenuation study. Pumping was not
reinitiated because attenuation via natural geochemical processes continues to be effective in controlling the
COCs. Overall, water levels in the SWA have declined approximately 2 to 3 feet during the five-year review
period covered in this report. The declining water levels and declining saturation thickness in the SWA support
the conclusion that there is no continuing recharge and the hydrostratigraphic unit is drying out. Overall in the
SWA, water levels (based on potentiometric surface maps water level graphs) have declined approximately 25
feet since 1989 and by approximately 2.6 feet during this current five-year period.
UNC/GE and others (NMED and NRC) have conducted several background ground water quality studies,
primarily focused on relationships between major ion concentrations (i.e. TDS, sulfate, and bicarbonate) and
uranium concentrations and the post-mining/pre-tailings ground water quality. Historically, only two ground
water constituents (sulfate and TDS) exceed the 1988 ROD standards in the SWA seepage-impacted water
seepage-impacted water outside the UNC property boundary. Sulfate and TDS also exceed the 1988 ROD
standards in the background water samples (Wells 627, EPA 28, and SBL-1). However, when compared to the
calculated Proposed BTVs (Table 6), there are no exceedances of TDS in any SWA wells, arid sulfate
exceedances occurred only in the downgradient background Well SBL-1 (Figure 7 and Table 6).
Mapping of bicarbonate isoconcentration contours is an important method of delineating SWA ground water that
has been impacted by contaminated seepage from the disposals cells on the Site (Figure 8). The area of seepage-
impacted water extends approximately 4000 feet along and southwest of the western margins of the Evaporation
Ponds on the South Cell of the Tailing Disposal Area (Figure 8) and extends approximately 1800 feet beyond the
UNC property boundary into Township 16 North, Range 16 West, Sections 3 and Section 10. The concentration
of dissolved uranium in seepage-impacted water is often a function of the bicarbonate concentration. Uranium
concentrations in the SWA seepage-impacted water occur within the same concentration range as the background
(post-mining/pre-tailings) ground water. As shown in Figures 9a and 9b, uranium concentrations have generally
attenuated in the alluvium as most of the seepage-impacted wells have shown overall stable trends since January
2001, when the extraction pumps were turned off, to the latest samples collected in October 2017. However, since
2009, samples collected from Well 509D, located northwest of the central cell, have consistently detected uranium
UNC Church Rock Uranium Mill Superfund Site Fifth Five-Year Review
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at concentrations exceeding the calculated BTV of 0.205 mg/L. The increasing uranium concentration found in
GW-3 may be the result of sampling with less than 2 feet of water in the well, leading to an increased
concentration of uranium. GW-3 has not been sampled since 2015, due to its location at the edge of Pipeline
Arroyo, which has eroded and is no longer safe to sample. Uranium concentrations found in upgradient wells *
0802 and 0808 and downgradient wells EPA 25 and EPA 28 are below proposed background standard of 0.205
mg/1. The spatial and temporal variability in SWA ground water uranium concentrations may be related to the
heterogeneity of the uranium distribution in the sediments, local geochemistry (e.g., bicarbonate), and hydrologic
factors (e.g., saturated thickness) that are not accounted for in the BTV statistical analysis.
Zone 3
The Zone 3 potentiometric surface contour map for the October 2017 monitoring event (Figure 10) indicates that
ground water flows toward the north and northeast, approximately parallel with the eastern limit of Zone 3
saturation. A time-series plot from January 1981 through January 2017 (Figure 11) shows the effects of former
pumping, current pumping, the former injection program, and natural drainage on Zone 3. From 2002 through
2016, most Zone 3 wells have shown overall decreasing ground water elevations (usually with small fluctuations)
at the depth where Zone 3 saturation and contaminant migration is diminishing as the Zone 3 ground water
continues to migrate away from the tailing cells as time goes on. Overall, Zone 3 water levels (based on saturated
thickness [Annual Monitoring Reports, Table 7] and potentiometric surface maps) have declined by
approximately 36 feet since 1989 and 3.0 feet during this current five-year period.
Zone 3 ground water sampling field measurements and contouring of pH values indicate the approximate area
impacted by tailings seepage in Zone 3 during the October 2017 sampling event (Figure 12). The extent of
seepage-impacted water was determined from pH and bicarbonate concentrations using: (1) seepage-impacted
wells, (2) background and former background wells, and (3) northern monitoring and extraction wells. Ground
water monitoring of the northern most Zone 3 wells indicates that this area is a complex zone of background
water and seepage-impacted water mixing, with some isolated areas that have historically contained seepage-
impacted water (i.e. Wells NBL-1 and PB-4 with less than pH 3). Based on all the latest sample information, the
seepage-impacted water in Zone 3 extends approximately 3600 feet northeast of the TDA and is constrained
within the UNC property boundary.
In general, COC concentrations in Zone 3 ground water are greatest in the highly acidic area of the plume (below
pH 4) within the seepage-impacted areas to the southwest (i.e., in Wells 517, 518, 613, and 717) found closest to
the TDA. During the 2017 ground water monitoring event, specific metals that exceed both the 1988 ROD
standards and calculated BTVs in samples from Zone 3 wells include: aluminum, beryllium, cobalt, manganese,
and nickel (Table 7).
Uranium, vanadium, and thorium-230 concentrations exceed the 1988 ROD standards and calculated BTVs in
Zone 3 ground water samples taken from Well 613, located immediately northeast/ downgradient of the TDA
north cell (Figure 13). Uranium concentrations also exceed the calculated BTV (0.395 mg/L) in Zone 3 ground
water samples from Well 717, located along the western margin of the plume. However, the uranium
concentrations found in Zone 3 ground water samples taken from Well 613 decreased significantly (from 1.1 to
0.73 mg/L) since 2013; whereas, uranium concentrations in Well 717 increased significantly (from 0.03 to 0.62
mg/L) since 2013. Sulfate concentrations in Zone 3 ground water samples taken from Well 717 also increased
significantly (from 4,450 to 7,300 mg/L) since 2013, indicating the effect of seepage-impacted water at this
location.
In Figure 14, UNC/GE has described two possible interpretations of uranium isoconcentration in Zone 3 ground
water. As reported in Hatch Chester (2018), "The two 2017 alternative maps in Figure 14 are provided due to the
uncertainty associated with the substantial water chemistry variability along the contact between seepage-
impacted and background water, as well as the limited uranium data in the center of the seepage-impacted area.
The Well 717 uranium concentration is likely to be a local effect of the seepage-impacted/background interaction,
UNC Church Rock Uranium Mill Superfund Site Fifth Five-Year Review
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as represented by the contours shown in Alternative 1. Alternative 2 provides for an alternative interpretation
relating the Well 717 uranium to the acidic core of the seepage-impacted water, based on the low pH observed at
the well."
UNC continues to evaluate the chemistry and water levels in the northern Zone 3 wells. UNC has modified the
pumping rates to optimize the extraction system operations in Zone 3. However, UNC's efforts to counteract the
overall northward hydraulic head and ground water flow is gradually approaching practical limits as the well
yields decrease.
On October 14, 2013, the Navajo Nation requested that UNC install sentinel monitoring wells on Navajo Nation
trust lands to track and monitor the ground water contamination in the Zone 3 hydrostratigraphic zone. UNC has
submitted applications to the Navajo Nation, requesting permits for these sentinel monitoring wells (see Figure
17). Installation of the sentinel monitoring wells is pending the approval of the permits, but is expected to be
completed in 2018. The proposed sentinel well locations were selected to validate the ground water flow model
and to determine if the working hypothesis mentioned in the preceding paragraph is accurate.
Zone 1
The Zone 1. potentiometric surface contour map for the October 2017 monitoring event (Figure 15) indicates that
ground water flows toward the north and northeast, similar to Zone 3 ground water flow. From 1999 through
2017, all Zone 1 wells have shown.gradual decreasing ground water elevations (with small fluctuations), as
ground water drains down-dip into partially saturated parts of this bedrock stratigraphic unit.
The temporary saturation of Zone 1 was created by the infiltration of former mine dewatering discharges. Zone 1
concentrations of COCs are considered background concentrations This anthropogenic ground water was later
impacted by acidic seepage-impacted water from Borrow Pit No. 2 in the Central Cell. Field-measured pH values
(below. pH 4) and chloride concentrations (above 50 mg/L) indicate the approximate area impacted by tailings
seepage in Zone 1. These samples were collected during the October 2017 sampling event (Figure 16). The results
show that the seepage-impacted water in Zone 1 extends to the east approximately 400 feet beyond the UNC ;
property boundary into Township 16 North, Range 16 West, Section 1.
Source remediation which consisted of neutralization and subsequent dewatering of the borrow pit was followed
by capping of the central cell. Neutralization of the seepage-impacted water continues by both natural
geochemical processes and with mixing seepage-impacted water with the background water. This has resulted in
reduced concentrations of most COCs below the cleanup standards (both 1988 ROD and calculated BTVs.
Tailings water that seeps out of the disposal cells contains elevated concentrations of metals and major ions,
including sulfate and chloride, that exceed both the 1988 ROD standards and calculated BTVs in Zone 1 wells
(Table 8).
Specific metals (cobalt and nickel) exceed both the 1988 ROD standards and calculated BTVs in samples taken
from Zone 1 wells (515A, 604, EPA-5, and EPA-7) during the 2013 through 2017 ground water monitoring
events..Manganese, chloride, chloroform, sulfate, and TDS also exceed the calculated BTVs in samples from
Zone 1 Well 515A which is located at the UNC property boundary with Section 1. Radionuclides (specifically,
combined radium-226/228) exceeded the 1988 ROD standard (5.0 pico Curies per Liter (pCi/L) in several Zone 1
wells throughout the current five-year review period, with concentrations ranging from 5 to 10.6 pCi/L (Table 8).
However, there were no exceedances of the calculated BTV (12.1 pCi/L) during the 2013 through 2017 ground
water monitoring events.
The amount of water seeping from the Site disposal cells into Zone 1 ground water has diminished since
.extraction pumping ceased in 1999. This indicates that the natural system has been effective in attenuating the
seepage-impacted water. The natural processes that are likely causing this attenuation are as follows:
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o Acidic seepage is being neutralized (buffered) and adsorption is occurring, resulting in attenuation of metals
and radionuclides.
° Natural geochemical conditions (i.e., gypsum equilibrium and bicarbonate availability) also are expected
to control sulfate and manganese concentrations in Zone 1.
Site Inspection
The inspection of the Site associated with this Fifth FYR was conducted on 10/31/2017. In attendance were Ms.
Janet Brooks, Remedial Project Manager, EPA-Region 6, with support from Mr. Steve Jetter and Mr. Angelo
Ortelli, of the NMED-GWQB, Superfund Oversight Section, and Mr. Rick Spitz, Project Manager and Contractor
on the Church Rock Project. The purpose of the inspection was to assess the protectiveness of the remedy.
Monitoring and extraction wells appeared to be in good condition and remain operational, except for SWA
monitoring wells GW-2 and GW-3, which have not been sampled since October 2015 because of their proximity to
areas of slope failure associated with Pipeline Arroyo.(Photographs 3 and 4, Appendix E). Other areas of slope
failure associated with Pipeline Arroyo were observed at the "Nick Point" (P'hotographs 5 and 6, Appendix E).
Apart from Pipeline Arroyo there was no evidence of erosion or slope failure in other areas of the Site. Native
vegetation has established itself on the radon barrier and protective rock cover placed within the tailings disposal
cells. A fence and locked gates surround the TDA. Barriers and warning signs surrounded the evaporation ponds
within the tailings impoundment area. Overall the Site appears to be weil maintained and managed.
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V. TECHNICAL ASSESSMENT
QUESTION A: Is the remedy functioning as intended by the decision documents?
Question A Summary:
The OU1 remedy addresses ground water contamination in Zone 1, Zone 3 and the SWA using ground water
extraction wells and treatment via evaporation. The OU1 ground water remedy was implemented and operated as
specified in the 1988 ROD.. However, as discussed in Section 4 of this report, ground water, extraction was shut
down in the SWA in 2001 for a natural attenuation test and was never restarted because natural attenuation was as
effective as pumping, for controlling the migration of COCs. Zone 1 was shut down in 1999 due to the inability to
maintain an adequate pumping rate. The ground water extraction and treatment system is currently only operating
in a limited extent in Zone 3; therefore, the overall Site ground water extraction system is no longer operating..
Ground water extraction continues at Zone 3 using wells along the seepage-impacted front, but it will likely be
discontinued in the future as site conditions continue to change.
The OU1 remedy performed as intended in the Zone 3 hydrostratigraphic unit until the ground water extraction
well systems started to reach the limit of their effectiveness. The reduced effectiveness is due to a loss in saturation
from insufficient recharge and a buildup of clays in the hydrostratigraphic matrix. Cleanup levels have not been
attained in Zone 3 because contaminant concentrations are dependent not only on pumping but also on the
influence of mine discharge water (i.e., current background conditions impacting the seepage-impacted water).
The Zone 3 ground water extraction wells are operational, but they require frequent maintenance. Most of the
Zone 3 extraction wells have yields that are below 0.5 gpm, due to precipitation of amorphous aluminosilicates
and encrustation of the well screens with iron oxyhydroxides, carbonates, and/or gypsum; alteration of feldspars
to clays in the sandstone matrix; and overall reduced saturated thickness of the hydrostratigraphic unit. UNC
continues to evaluate the chemistry and water levels in the northern Zone 3 wells and have modified the pumping
rates to optimize the extraction'system operations. The effort to counteract the overall northward hydraulic head
and ground water flow is gradually approaching practical limits as the well yields decrease. In short, Zone 3
ground water extraction and treatment most likely will be discontinued due to the impracticability of pumping
water from wells that are running dry.
Declining pumping system performance was anticipated in the 1988 ROD (Appendix A), which states that
"operational results may also demonstrate significant declines in pumping rates with time due to insufficient-
natural recharge of aquifers" and "In the event that saturated, thicknesses cease to support pumping, remedial
activity would be discontinued or adjusted to appropriate levels." In addition, the 2013 FYR also acknowledged
the technical difficulties of achieving site ground water cleanup levels using engineering controls. The 2013 FYR
said that institutional controls may need to play a greater role in protecting human health. Although the extraction
systems are not operating, except to a limited extent in Zone 3, natural geochemical processes are continuing to
attenuate the seepage-impacted plumes within each of the contaminated hydrostratigraphic units.
The 1988 ROD did not formally establish any ICs; however, as discussed in Section 2, certain enforcement
documents, governmental controls, and informational'controls are in place. In addition, informational controls
such as signs are posted near the TDA (with "No Trespassing" signs) and surround the Site.
However, there are currently no ICs restricting the use of seepage-impacted water that has advanced beyond the
NRC Licensed Site boundary in Sections 2, 3, and 10, and on Navajo Trust land to the north of Section 36.
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QUESTION B: Are the exposure assumptions, toxicity data, cleanup levels, and remedial action objectives
(RAOs) used at the time of the remedy selection still valid?
Question B Summary;
Exposure Assumptions
There have been no changes to land use and no drinking water wells have been installed near the Site. Therefore,
there is no current exposure pathway and, hence, the remedy remains protective in the short term. However, the
long-term protectiveness of the remedy is contingent upon achieving protective cleanup levels within the aquifers.
Toxicity Data and Cleanup Levels
New federal MCLs identified in Table 1 are based on updated toxicological information and, therefore, are
considered by the EPA to be protective. To ensure the long-term protectiveness. of the remedy, it is recommended
that these new MCLs be evaluated for potential as revised ARARs and TBCs for this Site. It should be noted that
some of the changes made to the federal MCLs are, or may be, below Site background concentrations and would,
therefore, not be appropriate requirements or TBC material. In such cases, the background concentration should
be evaluated in lieu of the new or revised standard or criterion.
New, Revised, Promulgated or Enacted Standards since the 1988 ROD
Many of the issues from the Fourth-FYR (2013) address the need to reconsider the ARARs in the 1988 ROD, as
many numerical standards from which the ARARs were established have changed since the issuance of the 1988
ROD. For this FYR we compared the contaminant-specific ground water ARARs to current ARARs. Current
ARARs reviewed for this comparison included the following: NMWQCC ground water standards, Maximum
Contaminant Level Goals (MCLGs) under the SDWA, MCLs, Treatment Technology Action Levels (TTLs),
Federal Secondary. Drinking Water Standards, NRC Ground Water Protection Standards (GWPS), and 10 CFR
Part 40 Appendix A (Criteria Relating to the Operation of Uranium Mills and the Disposition of Tailings or
Wastes Produced by the Extraction or Concentration of Source Material From Ores Processed Primarily for Their
Source Material Content) at Table 5C (Maximum Values for Ground-Water Protection). This comparison found
that there are multiple analyte specific performance standards in the 1988 ROD that allow concentration levels of
a contaminant that are greater than a current ARAR standard (see Table 1). Performance standards in the 1988
ROD for the following contaminants allow concentrations that exceed current ARARs: aluminum, antimony,
arsenic, beryllium, cadmium, iron, lead, manganese, nickel, thallium, vanadium, uranium, sulfate, nitrate, and
TDS. In addition to the 1988 ROD allowing higher concentrations of current ARARs, EPA's comparison found
that there are performance standards in the 1988 ROD that call for concentrations of contaminants that are lower
(i.e., more conservative) than the current ARAR. These more restrictive performance standards in the 1988 ROD
include performance standards for barium, chromium, copper, and silver. EPA has summarized the results of its
comparison of current ARARs to the standards in the 1988 ROD in Table 1. If current ARAR concentration
standards are lower (i.e., more restrictive) than the 1988 ROD standards, then the current ARAR standards are in
light blue. If current ARAR standards are higher (i.e., less restrictive), then the current ARAR standards are in
light gray. Table 1 also includes one contaminant and one contaminant group that were not included in the 1988
ROD ARARs where a ground water standard exists and may be considered a potential COC. These are lead-210
and Total Trihalomethanes (TTHMs).
Remedial Action Objectives and Remediation Goals
The RAOs (EPA 1988) were described as follows:
• contain down-gradient contaminant migration within each target area;
UNC Church Rock Uranium Mill Superfund Site Fifth Five-Year Review
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• restore ground water down-gradient of the Tailings Disposal Area, to the maximum extent practicable, to
meet the cleanup criteria; and
• restore ground water at the Tailings Disposal Area to a level that allows attainment of cleanup criteria at
its boundary.
The RAOS are still considered to be valid objectives. However, as discussed above, it has not been possible to
completely achieve the RAOs.
However, as stated in Appendix A-of the 1988 ROD, it was anticipated that cleanup goals (which-are referred to as
remediation goals under the 1990 NCP) might not be reached within a reasonable time period due to the
hydrogeologic characteristics of the hydrostratigraphic units and due to the fact that ground water extraction well
systems have started to reach the limit of their effectiveness.
UNC submitted a license amendment request to the NRC in April 2012, that proposed revisions to the GWPS in
the license based on updated BTVs for the following COCs: arsenic, cadmium, gross alpha, lead, iead-210, nickel,
radium-226 and -228, selenium, thorium-230, and uranium.
QUESTION C: Has any other information come to light that could call into question the protectiveness of the
remedy? *
Question C Summary
There have been no changes to land use and no drinking water wells have been installed near the Site. Therefore,
there is no current exposure pathway and, hence, the remedy remains protective in the short term. However, the
long-term protectiveness of the remedy is contingent upon achieving protective cleanup levels within the
individual hydrostratigraphic units (i.e. SWA, Zone 3, and Zone 1).
No other information has come to light that could affect the protectiveness of the remedy. There are no additional
risks or previously unidentified risks that could affect performance or protectiveness of the remedy.
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VI. ISSUES/RECOMMENDATIONS
Issues and Recomr
nendations Identified in the Five-Year Review:
OU(s): 1
Issue Category: Other
Issue: MCLs for certain contaminants of concern on the Site have changed, and these
changed MCLs are applicable or relevant and appropriate requirements (ARARs) for the
Site. EPA's policy regarding newly promulgated or modified environmental requirements
that are promulgated or modified after a ROD is signed is that EPA will not reopen the
remedy selection decision made in the ROD unless the new or modified requirement calls
into question the protectiveness of the selected remedy. EPA believes that it is necessary
to "freeze ARARs" when the ROD is signed. To do otherwise would disrupt CERCLA
cleanups, whether the remedy is in design, construction, or in remedial action. Each of
these stages represents significant time and financial investments in a particular remedy.
V
Recommendation:
Determine if the changes in MCLs warrant a change in Remediation Goals for the remedy
to remain protective.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party Responsible
Oversight
Party /Support
Agency
Milestone Date
No
Yes
EPA
EPA/State
6/30/2020
OU(s): 1
Issue Category: Remedy Performance
Issue: The effectiveness of the Zone 3 O&M activities in controlling contaminant
migration from the Site needs to be assessed and adjusted accordingly since mine
discharge water may be drawing into the Zone 3 pumping wells.
Recommendation:
Evaluate the current extraction pumping in Zone 3, to determine whether it is effective at
controlling contaminant migration from the Site. In particular, the upgradient well series
(i.e., RW-series) should be evaluated to determine whether it is drawing in background
water (i.e., water that was contaminated mine discharge, but that was not contaminated by
tailings from the UNC mill) from the west.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party Responsible
Oversight
Party/Support
Agency
Milestone Date
No
Yes
PRP
EPA/State
1/31/2019
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OU(s): 1
Issue Category: Remedy Performance
Issue: Current pumping will reach a point where an extraction well will not be able to
withdraw water from the Zone 3 hydrostratigraphic unit. At this point in time, the Zone 3
contaminated water will still migrate northward toward the Navajo Reservation.
Recommendation:
Continue efforts to minimize northward advancement of the Zone 3 ground water that has
been impacted by contaminants that seeped from Site tailings. These efforts should
forestall contamination of aquifers underlying Navajo land where drinking water wells
may be installed in the future. As part of these efforts, where practicable, extraction of
contaminated ground water from Zone 3 should be continued in the northernmost
extraction wells. These northern wells are located at the leading edge of the ground water
that has been impacted by contaminants that seeped from Site tailings. Evaluate expanded
use ofNatural attenuation. 1
Affect Current
Protectiveness
Affect Future
Protectiveness
Party Responsible
Oversight
Party/Support
Agency
Milestone Date
No
Yes
PRP
EPA/State ¦
1/31/2019
OU(s): 1
Issue Category: Institutional Controls
Issue: Although no Navajo are currently using ground water that is contaminated with
contaminants of concern (COCs) from the Site, there is a potential for water supply wells
to be installed in areas that may become impacted with hazardous substances.
Recommendation:
Renew efforts with stakeholders (e.g., the Navajo Nation and local residents) to establish
Institutional Controls (ICs) that will restrict the use of contaminated ground water on
Navajo, Tribal Trust, and Indian Allotment lands (and unrestricted fee lands, if any) in all
three hydrostratigraphic units.
Affect Current
Protectiveness
Affect Future
Protectiveness
Party Responsible
Oversight
Party/Support
Agency
Milestone Date.
No
Yes
PRP
EPA/State -
6/30/2019
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VII. PROTECTIVENESS STATEMENT
Operable Unit: Protectiveness Determination:
OU1 Short-term Protective
Protectiveness Statement: .
The remedy at OU1 (the final source remedy) currently protects human health and the environment in the short
term, because the remedial actions have minimized potential human exposures to contaminants in ground water
and have reduced the potential for the repository tailings to act as a source of ground water contamination.
However, in order for the remedy to be protective in the long term, the action items identified in this report should
be implemented.
Operable Unit: Protectiveness Determination:
OU2 Will be Protective
Protectiveness Statement:
The OU2 remedy is expected to be protective of human health and the environment upon completion.
Protectiveness Determination:
Short-term Protective
Protectiveness Statement:
Remedial actions at both OUs are currently protective of human health and the environment; therefore, the Site-wide
remedy is and remains protective in the short term.
For the ground water exposure pathway, there is currently no known human exposure. However, follow-up actions
are needed to achieve long-term protectiveness because the remedial progress of the ground water containment and
restoration systems are reaching the limits of their effectiveness. Greater reliance on natural attenuation should be
evaluated, and expanded used of institutional controls may be necessary for the ground water remedy to be
protective in the long term.
VIIL NEXT REVIEW
The next five-year review report for the Site is required five years from the completion date of this review.
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TABLES
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Table 1 -1988 ROD ARARsfor OU1 and New, Revised, Promulgated or Enacted Standards since the 1988 ROD
Contaminant
1988 ROD
Concentration
(mg/L)
unless noted
ARAR Source Identified
in ROD
2013
NMWQCC
GW
Standard
2018 MCL,
TTLs or
Secondary
DW
Standard"
NRC
GWPS
(mg/L)
unless
noted
NRC GW
Protection
Listb
Aluminum
5
NMWQA'
5
0.05 to 0.2
Antimony
0.014
HEALTH-BASED
0.006
Arsenic
0.05
MCL
0.1
0.01
0.05
0.05
Barium
1
MCL, NMWQA'
1
2
1
Beryllium
0.017
HEALTH-BASED
0.004
0.05
Cadmium
0.01
MCL, NMWQA'
0.01
0.005
0.01
0.01
Chromium
0.05
MCL, NMWQA'
0.05
0.1
0.05
Cobalt
0.05
NMWQA'
0.05
Copper
1
NMWQA'
1
1.3
Iron
5.5
BACK-GROUND
1
0.3
Lead
0.05
MCL, NMWQA'
0.05
0.015
0.05
Manganese
2.6
BACK-GROUND
0.2
0.05
Mercury
0.002
MCL, NMWQA'
0.002
0.002
0.05
0.002
Molybdenum
1
NMWQA'
1
Nickel
0.2
NMWQA'
0.2
0.05
Selenium
0.01
MCL
0.05
0.05
0.01
0.01
Silver
0.05
MCL, NMWQA'
0.05
0.1
0.05
Thallium
0.014
HEALTH-BASED
0.002
Vanadium
0.7
HEALTH-BASED
0.1
Zinc
10
NMWQA'
10
5
Chloride
250
NMWQA'
250
250
Sulfate
2,160
BACK-GROUND
600 8
250
Nitrate
30
BACK-GROUND
108
10
TDS
3,170
BACK-GROUND
1000«
500
Radium-226 And 228
5C
MCL
30c
5C
5C
Uranium - 238
5
NMWQA'
0.03
0.03
Uranium - 238
Or 1,645c
Thorium-230d
15c
MCL
5C
Gross Alpha
15c
MCL
15c
15c
15c
Lead - 210
NA
NA
lc
TTHMs e
NA
NA
0.1
0.08
0.08
Notes: Current standards less than the 1988 ROD ARAR are highlighted in blue and current standards greater than a 1988
' Federal Maximum Contaminant Level, Treatment Technology Action Level (TTLs), or Secondary Drinking Water Standard
b 10 CFR Appendix A to Part 40 - 5C-Maximum Values for Ground Water Protection
c pCi/L
d based on 15 pCi/L Gross Alpha
e Total trihalomethanes -
include chloroform; TTHMs MCL = 0.08 mg/L; in addition, chloroform has an MCLG = 0.07 mg/L
'ROD Identifies NMWQA as Source for State of NM ARARs - NM numerical standards are from the NM Water Quality
g NMED Recommended Background Values according to a letter to EPA January 1998 differs from current NMWQCC
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Table 2 - 1988 ROD Cleanup Levels and Contaminants Exceeding ARARsfor each Hydrostratigraphic Unit
Hydrostratigraphic Units
Contaminant
Value
Units
SWA
Zone 3 Zone 1
Aluminum
5
mg/L
X
X
Antimony
0.014
mg/L
Arsenic
0.05
mg/L
X
X
Barium
1
mg/L
Beryllium
0.017
mg/L
Cadmium
0.01
mg/L
X
X
X
Chromium
0.05
mg/L
Cobalt
0.05
mg/L
X
X
X
Copper
1
mg/L
Iron
5.5
mg/L
Lead
0.05
mg/L
Manganese
2.6
mg/L
X
X
X
Mercury
0.002
mg/L
Molybdenum
1
mg/L
X
X
X
Nickel
0.2
mg/L
X
X
X
Selenium
0.01
mg/L
X
X
X
Silver
0.05
mg/L
Thallium
0.014
mg/L
Vanadium
0.7
mg/L •
Zinc
10
mg/L
Chloride
250
mg/L
Sulfate
2160
mg/L
Nitrate
30
mg/L
X
X
X
Total Dissolved Solids (TDS)
3170
mg/L
X
X
X
Radium 226 & Radium-228
5
pCi/L
X
Uranium-238-
5
or 1645
mg/L
pCi/L
Thorium-230
15
pCi/L
Gross Alpha
15
pCi/L
X
X
X
Notes:
1 SWA = Southwest Alluvium.
2 mg/L= milligram per liter, pCi/L =
picocurie per liter.
3 EPA cleanup levels represent NMWQCC standards for Aluminum, Cobalt, Copper, Molybdenum,
Nickel, Zinc, Chloride, and Uranium.
4 EPA cleanup levels represent MCLs for Arsenic, Barium, Cadmium, Chromium, Lead, Mercury,
-Selenium, Silver, Radium-226, Radium-228, Thorium-230, and Gross Alpha; numerically identical
NMWQCC standards existed for Barium, Cadmium, Chromium, Lead, Mercury, and Silver.
5 EPA cleanup levels represent background levels for Iron, Manganese Sulfate, Nitrate, and TDS.
6 EPA cleanup levels represent health-based criteria for Antimony, Beryllium, Thallium, and Vanadium.
7 Although some NMWQCC standards and MCLs are numerically identical, the state standards
J represent dissolved concentrations, while the federal MCLs represent total concentrations.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Table 3 -1988 ROD Cleanup Level Compared to Proposed Cleanup Levels
1988 ROD
Proposed Cleanup Levels
Contaminant
Cleanup Level
Units
SWA
Zone 3
Zone 1
Aluminum
5.0
mg/L
5
5
5
Antimony*
0.014
mg/L
. -
-
-
Arsenic
0.05
mg/L
0.01
0.757
0.01
Barium*
1.0
mg/L
--
-
-
Beryllium
0.017
mg/L
0.004
0.004
0.004
Cadmium
0.01
mg/L
0.025
0.09
0.01
Chromium*
0.05
mg/L
-
-
-
Cobalt
0.05
mg/L
0.05 .
0.391
0.05
Copper*
1.0
mg/L
-
-
--
Iron*
5.5
mg/L
--
-
Lead
0.05
mg/L
0.07
0.08
0.05
Manganese
2.6
mg/L
2.1
9.1
5.4
Mercury*
0.002
mg/L
--
-
-
Molybdenum
1.0
mg/L
1
66.1
1
Nickel
0.2
mg/L
0.2
0.569
0.2
Selenium
0.01
mg/L
0.07
0.05
0.05
Silver*
0.05
mg/L
...
-
Thallium*
0.014
mg/L
~
-
-
Vanadium
0.7
mg/L
0.1
0.1
0.1
Zinc*
10.0
mg/L
--
-
-
Chloride
250.0
mg/L
250
250
250
Sulfate
2160.0
mg/L
5815
5693
5539
Nitrate
30.0
mg/L
536.6
190
190
Total Dissolved Solids (TDS)
3170.0
mg/L
10376
8592
8020
Radium-226 and Radium-228
5
pCi/L
8.2
35.2
12.1
Uranium-238**
5.0
pCi/L
N/A
0.395
. 0.238
Thorium-230
15
pCi/L
4.5
17
1.6
Gross Alpha
15
pCi/L
15
39.7
15
Chloroform***
--
mg/L
0.08
0.08
0.08
Pb-210**
--
pCi/L
5.9
5.7
4.7
Notes:
* Contaminant removed from consideration during 1989 Remedial Design
**Calculated BTV=0.2050 mg/L. Historic background up to 0.367 mg/L from mine water
discharge. UNC/GE recommends adoption of 0.03 mg/L.
*** Contaminant regulated by NRC.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Table 4 - Protectiveness Determinations and Statements from the 2013 Five-Year Review Report
OU#
Protectiveness
Determination
Protectiveness Statement
1
Short-term
Protective
The remedy at OU1 (the final source remedy) currently protects human health and
the environment in the short term. Actions taken have minimized potential human
exposures to contaminants found in the ground water and reduced the potential for
the repository tailings to act as a source of ground water contamination.
For the remedy to be protective in the long term, the following actions need to be
taken:
1. Evaluate and revise the estimated background contaminant levels at the Site
and reevaluate Site cleanup standards {i.e., remediation goals) through the
NCP decision-making process.
2. Complete the ongoing SWSFS Part III to develop and analyze remedial
alternatives.
3. Continue the experimental efforts to create a subsurface hydraulic barrier
in Zone 3 to slow down and contain the migration of the seepage-
impacted water in the northern subsurface area.
4. Determine whether the SWA extraction wells have provided
improvement in ground water quality with respect to uranium
contamination when compared to Natural Attenuation.
5. Evaluate the use of various mechanism(s) of Natural Attenuation in the
SWA for uranium as well as for other COCs in all hydrostratigraphic
zones as part of the ongoing remediation effort to attain cleanup
standards.
6. Renew efforts to establish ICs that will.help protect human health
by restricting the use of contaminated ground water on affected
Navajo Nation, Tribal Trust, and Indian Allotment lands.
7. Evaluate whether a Technical Impracticability (Tl) waiver is appropriate
for the ARARs related to sulfate and TDS. This evaluation would be done
as part of the ongoing SWSFS, Part III.
8. Evaluate the anthropogenic origin and the transient nature of the
artificially created ground water hydrostratigraphic units impact on
future EPA ground water decision making.
2
Will be
Protective
The surface soil operable unit (OU2) remedy described in the 2013 OU2 ROD, which
provides for the disposal of NECR mine waste at the Site TDA, is expected to be
protective of human health and the environment upon completion. At present [i.e.,
in 2013], remedial design activities are underway which will adequately address all
exposure pathways that could result in unacceptable risks associated with OU2.
Sitewide
Short-term
Protective
The remedial action that has been taken to address ground water contamination at
the Site and the remedial action that has been taken to address contamination on
the surface of the Site are presently protective of human health and the
environment and should remain protective in the short term.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Table 5 - Status of Recommendations from the 2013 Five-Year Review Report
OU#
Issue
Recommendations
Current
Status
Current
Implementation Status
Description (additional
discussion below table
included in text)
Completion
Date (if
applicable)
1
1. The 1988 ROD did
not provide a clear
evaluation of the
post-mining/pre-
tailings background
water quality in
establishing the Site
cleanup standards.
Evaluate and revise the
estimated background
contaminant levels at the
Site and reevaluate Site
cleanup standards (i.e.,
remediation goals)
through the NCP decision
making process.
Ongoing
NRC revised ground
water protection
standards based on
updated Background
Threshold Values (BTVs)
for the Site. NRC
approved the BTVs in
2015. EPA has not acted
on the proposed BTVs in
a decision documient.
N/A
1
2. The ground water
remedy cannot attain
the cleanup levels
within a reasonable
time frame because
the source of
anthropogenic
recharge to the
ground water system
is no longer available
and has resulted in a
significant loss of
aquifer saturated
thicknesses.
Complete the ongoing
SWSFS Part III to develop
and analyze remedial
alternatives.
Ongoing
EPA Region 6 will stop
work on the SWSFS Part
III determination until
after EPA Region 9
completes a water
quality investigation of
the NECR and Quivira
mines (see Error!
Reference source not
found, section below).
Stop Work
1
3. The Zone 3
extraction well
system cannot
hydraulically control
the migration of
tailings seepage-
impacted water
northward toward
and eventually on to
the Navajo Nation
lands.
Continue the
experimental efforts to
create a subsurface
hydraulic barrier in Zone 3
to slow down and contain
the migration of the
seepage^impacted water
in the northern subsurface
area.
Ongoing
The Zone 3 extraction
system has been
declining in
performance due to the
decreasing amount of.
water that is being
extracted;
consequently, active
remedial operations in
Zone 3 are reaching the
limits of their
effectiveness.
N/A
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Table 5 - Status of Recommendations from the 2013 Five-Year Review Report (continued)
Current
Implementation Status
Description (additional
Completion
Current
discussion below table
Date (if
OU#
Issue
Recommendations
Status
included in text)
applicable)
1
.4. The question still
Determine whether the
Under
The SWA extraction
N/A
remains as to
SWA extraction wells have
Discussion
system has remained
whether or not the
provided improvement in
idle since 2001 due to
operation of the
ground water quality with
only sulfate and TDS
extraction system in
respect to uranium
migrating out of the
the SWA is effective
contamination when
tailing cells. TDS and
for improving ground
compared to natural
sulfate are secondary
water quality with
attenuation.
drinking water
respect to uranium
standards, which are not
and whether natural
remediation goals at the
attenuation can be
Site. Significantly, the
relied upon as part of
natural geochemistry of
the remedy to
\
the ground water
mitigate tailings
appears to be effective
seepage impacts on
for improving ground
ground water.
water quality with
respect to uranium
concentrations.
1
5. Uranium
Evaluate the use of
Under
UNC/GE submitted an
N/A
concentrations in the
various mechanism(s) of
Discussion
expanded list of
SWA ground water
natural attenuation in the
proposed BTVs in 2015,
do not exceed the
SWA for uranium as well
including.COCs
uranium cleanup
as for other COCs in all
addressed in the 1988
level of 5.0
hydrostratigraphic zones
ROD. The updated BTVs
milligrams per Liter
as part of the ongoing
for each EPA-regulated
(mg/l) called for in
remediation effort to
COC were critically
the 1988 ROD.
attain cleanup standards.
compared to ARARs and
However, they do
the ROD standards to
exceed the 2003
propose appropriate
promulgated EPA
cleanup levels for COCs.
Safe Drinking Water
EPA has not formally
Act (SDWA) MCLfor
approved of the
uranium of 0.030
proposed BTVs. EPA has
mg/l.
not acted on the
proposed BTVs in a
decision document.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Table 5 - Status of Recommendations from the 2013 Five-Year Review Report (continued)
OU#
Issue
Recommendations
Current
Status
Current
Implementation Status
Description (additional
discussion below table
included in text)
Completion
Date (if
applicable)
1
6. In light of the
technical difficulties
of achieving Site
ground water
cleanup levels using
engineering controls,
ICs may have to play
a larger role in
protecting human
health at the Site.
Renew efforts to establish
ICs that will help protect
human health by
restricting the use of
contaminated ground
water on affected Navajo
. Nation, Tribal Trust, and
Indian Allotment lands.
Under
Discussion
Efforts to discuss ICs
with the Navajo Nation
have not been renewed
01/31/2019
1
7. Sulfate and TDS
concentrations are
not dependent on
continued operation
of extraction systems
in the hydro-
stratigraphic units at
the Site, but rather
these constituent
concentrations are
controlled by natural
geochemical
reactions, primarily
the chemical
equilibrium with
gypsum and/or
anhydrite.
Evaluate whether a Tl
waiver is appropriate for
the ARARs related to .
sulfate and TDS. This
evaluation would be done
as part of the ongoing
SWSFS, Part III.
Under
Discussion
Statistical evaluation of
the background sulfate
and TDS concentrations
has been completed.
EPA has not acted on
the proposed BTVs for
sulfate and TDS.
N/A
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Table 5 - Status of Recommendations from the 2013 Five-Year Review Report (continued)
OU#
Issue
Recommendations
Current
Status
Current
Implementation Status
Description (additional
discussion below table
included in text)
Completion
Date (if
applicable)
1
8. Background water
at the Site is not a
natural water source
but instead an
anthropogenic
artificial aquifer
created by mine
water effluent that
was pumped from
the Westwater
Canyon Member of
the Morrison
Formation, which
contains the uranium
ore body.
Evaluate the
anthropogenic origin and
the transient nature of the
artificially created ground
water aquifers impact on
future EPA ground water
decision making.
Under
Discussion
UNC/GE used statistical
analysis of water
, chemistry from wells
located outside of the
seepage-impacted area
to calculate BTVs from
the mine discharge
water that infiltrated
the subsurface prior to
the mill tailings seepage
impact. UNC/GE
submitted an expanded
list of BTVs in 2015,
including COCs
addressed in the 1988
ROD. The updated BTVs
for each EPA-regulated
COC were critically
compared to ARARs and
the ROD standards to
select appropriate
cleanup levels. EPA has
not acted on the
proposed BTVs in a
decision document
N/A •
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Table 6- Detected Constituents m Southwest Alluvium, October 2017
information Source: 2017 AMR (Hatch-Chester, 2018}
Chemical Name
MRt
license
1988 ROD
Cleanup
level
PmpMari
BTV
Cleanup
Level
Unit
0509 D
0624
062?
0632
0801
0802
0803
0808
EPA13
EPA2S
EPA28
EPA 28
m
ewi
sut-at
ALUMINUM
S
5
mg/i
0.2
0.4
AMMONIA IAS N)
_
„
mg/S
0.2
8,1
4,4 D
0.13
1.21
0,48
BICARBONATE !HC03)
..
... Ml/!..
2500
1670
600
1600
2140
1590
mm
1360
1440
432
440
1S00
—41.?.. ..
CALCIUM
mg/I
87?
688
SB
547
570
638
614
64$
649
795
491
482
676
477
CHLORIDE
250
250
mg/!
¦m
212 D
31 D
2430
200 0
173 D
142 0
172 D
117 D
14SD
98 D
98 D
240 D
no
CHLOROFORM
80
80
_J
0.66
2.1
0.58
0.91
COBALT
)5
0.01
0.01
__
0,03
__
..pei/!.
0.7
u
0.8
0.6
07
0,8
LEAD
0-07
0.05
0.07
m«/i
0.002
0.001
LEAD-21Q
5,9
5.9
pcl/l
1.6
l.S
MAGNESIUM
nig/il
41?
434
226
789
782
740
661
641
391
242
469
463
577
ii»
MANGANESE
2.6
2.1
mi/I
0.14
0.15
2.4
~
¦
0,44
0.4t>
0.49
0.1
-jfl-
NICKEL
0,078
0.2
mg/l
0.12
MttftflMOtt
536,6
mgf |
8.70 0
JEST
73.0 D
mi.
Tssir
isir
29.5 D
18.7 D
TEST
7.OS D
7.20 D
77.5 O
iiiat
PH (FIELD)
..
tu
6.57
6.36
6 49
6.61
6.52
~655i
t"» 52 '
6.68
8,72
6.88
«.K
6.67
6.61
PHtlABS
...
su
___p
6.63 H
7.02 H
6.60 H
6.72 H
6.62 H
1
1
6.70 H
CJ5.H
6.93 H
u
6.73 H
1
_
mg/l
———j
§
5
10
12
6
11
10
7
10
10
9
»
_____
pci/l..
0,3
0.2
0.2
0,5
0.2
—
0,3
0.5
0,4
RADIUM-228
pcl/l
l.S
1.6
l.S
2.6
_______ _j
8.2
'•
8.2
pci/l
1.8
0.2
0.2
2.1
0.2
n
0.3
0.3
0.3
2
3
SODIUM
mg/l
413 D
308 0
364
378 D
332 D
249 0
337 D
151
219 D
252
249
4180
2*00
______
:>o
5815
mg/l
2190 O
210)0
"TBSF
BUS
itMM
TSIir
Talari
Jim.,
JHHL
1790 D
jfflBP
Mi
iiM
...astiiL
THORIUM-230
4.5
15
4.S
..§8ll,
TOTAL DISSOLVED
SOLIDS (LAB)
3170
10376
mg/l
5890
OH
im
ISST
ssic
"ussr
64 SO
HI
ISPl
ISPS?
18111
4440 0
' MMB
4350 D
S840D
3870 D
TOTAL
TRIHALOMETHANES
80
80
m/i
0.66
2.1
0,58
0.91
URANIUM
03
5
0.2GS
,!2S/i
IV,.
0.042
0.021
0.07S9
0.0407
0.149
0.0696
0.0841
0.0351
0.13
0.0211
0.0218
5
0.0102
Notes: Table modified by EPA,
— means that a cleanup level was not established for the analyfe
Blank shaded values indicate that the anaiyte was not detected
Gray shaded ttlun exceed the 1988 ROD Cleanup Levels
BTV Cleanup level
>ij« rthllw) exceed both the 1988 ROD Cleanup levels and the Pioposed BTV Cleanup levels
D indicates that the sample was diluted tor analysis
H indicates that the analysis was performed beyond the analytical method holding time
FD indicates a field duplicate sample
UNC Church Rock Uranium Mil! Superfund Site
September 2018
Fifth Five-Year Review
-------
i Ai6/f> Gittst^€mstitueMshlomX^t'obtr20sf
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0,14
0.64
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3,07
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3.20H
5.6SH
ft.OSH
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-
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SOOIUM
-
mg/S
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J-Wt)
TTTd""
u&n
3130
"'"lg3pa,,u
ifilO
i4^a
1720
ssjr>'
%4SD
isio
l?i 0
141D
s. u
SULFATE4S04)
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rag/5
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pi'i/i
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8WW
mg/i
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Mil
Wsi
6100 D
HISSST
H8W
Wx§
»
4
M
0.52
;
-
6.995
^_......
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0.148
0 ?S4
iz
0,0164
0.009
' 0.0^)7
n,i%
l»0 >JW
'OOLH
VANADHJM
OJ
0 •
0 1
¦
Notov. labte moricfta* by EPA,
- m*am that a fteanup tevcf r>ot estabfcshad *or lbs aairtylc
Wan* v»»ues itfrtir.ai'C that »f»e not dfttcted
u'« >i»4wW VSHm «**.«*<1 rt>« 1988 $00 Owhh> levels
•M I'he Proposed §7V Cleanup U-w!
tti ths 1988 ROD Ck>*nup iav<»h anri tb« Propose* 81V Cleanup
&¦ rv»<*>h'# W*rl toot»rr»»na?iii*\
D ftc0O» rir»g !!m.i s«crs?a$s^dus? to sample m*\nx
H p*rfart»**st tK.omnwu^d hoMmf t>n*
< n wdsc^M i «wM iupbcat# samp?®
UNO Ch-.i''.:h Rock l.-ra^iun Mill Su^erfui-d S.t«
S
-------
Table 8- Detected Constituents in Zone 1, October 2017
Information Source: 201? AMR (Hatch-Chester, 2018)
Chemical Nam*
NRC
License
Standard
1988 ROD
Cleanup
level
PnpMHt
BTV
Cleanup
level
Unit
0142
0515 A
0664
8614
EPA02
EPA02R3
EPA 04
Emm
6PA07
ALUMINUM
5
mg/l
0.2 D
1
0.1
0,7
AMMONIA (AS N)
..
..
mg/l
21 D
73 D
0.2?
0.43
8.8 D
BICARBONATE (HC03)
mg/l
348
862
31
290
303
167
__
48
M2
CALCIUM
-
mg/l
66
455 D
445
5SS
406
411
457
4§6
CHLORIDE
250
2S0
mg/l
17
96 D
¦¦r-
, hh
24
24
34 0
16 O
2130
CHLOROfOftl
80
80
m!L
Tmr..
13
42
0.54
0*
COBALT
0.05
0 «.
mg/l
0.02
0,03
""""TMBT-""
M
GROSS ALPHA
15
15
15
pci/l
m
2.9
1.9
1,1
1.8
1.5
2.1
«
a
0.05
0.05
o.os"
mg/l
0.005
IE
..
4.?
pcl/l
1.3
1.3
mmsmsum
mg/l
34
1320
803
$W
194
195
379
465
__
171
MANGANESE
2.6
5.4
mg/l
0.04
4.04
0.93
1,83
1.85
3.42
1.8
0,0?
0.2
0.2
mg/l
¦
0,1
N1TRAT
3D
190
0.49
SMM
§lfl»
""HMF"
0,1
0.02
0.59
8,05 D
Hi
PI
7.89
5.98
5.38
6.38
6,95
6.93
li 78
6,29
iJB9
___ —— -—J
su
7,40 M
8.14 H
5.43 H
6.57 H
b.93 H
6,72 H
6.78 H
6.01 H
IH
POTASSIUM
mg/l
4
18
12
14
7
7
9
7
i
FtAMUM-226
pcl/l
0.7
2
1,3
0.7
Is
1,6
0,9
1.2
0.5
RADIUM 228
pci/l
6.5
5.8
4.4
5.6
S.l
4.4
4.8
3.3
RADIUM 226 & 228
12.1
5
sTi
pci/l
J 6
12
,_g_.
7.1
T"
S.J
6
3.8
SELENIUM
0.01
0,01
0.05
mg/l
0.003
0.002
SODIUM
mg/l
315
603 D
.108 0
468 D
207
208
»1
105
3MB
SULFATE («M)
2160
5539
mg/l
667 0
8S8BT
Milf
*™Wi
18900
18800
HHV
THQRIUM-230
1.6
15
1.6
pcl/l
:
TOTAL DISSOLVED SOLIDS (LAB)
3170
mm
mg/l
13100
M§§
"HHKT
¦HI
"HISST
""HjjBli-
"Hswn
TOTAL TRtHALOM ETHANES
80
80
. .Hl/»
13
0.54
0.95
URANIUM
0.238
5
0.23*
rag/I
0.0095
00004
0.0464
0,0013
0.0012
0.0019
0.0019
Notes: Table modified fay EPA.
— means that a cleanup level was riot established for the anatyte
Blank shaded values indicate that the analyte was not detected
Gray shaded values exceed the 1988 ROD Cleanup levels, yellow shaded values exceed NRC license Standard
frttt .taints exceed the Proposed 8TV Cleanup lew the 1988 ROD Cleanup Levels and the Proposed BTV Cleanup levels
D - Reporting limit increased due to sample matrix FD indicates a field duplicate sample H • Analysis performed past recommended holding time
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth five-Year Review
-------
Table 9 - SWA Proposed Background Threshold Value Cleanup Levels based on UPL95 Summary Comparisons (Chester Engineers, 2015b)
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UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Table 10 - Zone 3 Proposed Background Threshold Value Cleanup Levels based on UPLB5 Summary Comparisons (Chester Engineers, 2015b)
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UNC Church Rock Uranium Mil! Superfund Site
September 2018
Fifth Five-Year Review
-------
Table 11 -Zone 1 Proposed Background Threshold Value Cleanup Levels based on UPL9S Summary Comparisons (Chester Engineers, 2015b)
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UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
FIGURES
Information Source: 2017 AMR (Hatch-Chester, 2018)
UNC Church Rock Uranium Mill Superfund Site
•September 2018
Fifth Five-Year Review
-------
FIGURE 1
Site Location Map
United Nuclear Corporation Church Rock Site,
Church Rock, New Mexico
HATCH
CHESTER
Figure 1: Site Location Map
LEGEND
¦imma Approximate Site Location
NEW MEXICO INSET LEGEND
• Major City
A Church Rock Site Location
Interstate Highway
I State Boundary
Notes:
1. Topographic basemap taken
from the United States Geologic
Survey 30x60 minute, 1:100,000
scale, Gallup, New Mexico
Topographic Map, 1981.
2. Data for New Mexico Inset map
taken from ESRI Data & Maps
2002 CD-ROM set.
1 0.5 0 1
diles
UNC Church Rock Uranium Mill Superfund Site Fifth Five-Year Review
September 2018
-------
Northeast Church
Rook Mine Ote
Quh/ira
Facilities
North Cell
Zone 3 Remedial
Action Target Aree
Pi peine Arroyo
Central CeU
Pipeline Arroyo
Nlckpoint
Zone 1 Remedial
Action Target Area
Borrow Pit No. 1
(Reclaimed)
Borrow Pll No. 2
(Recleimed)
SECTION 1
Southwest Alluvium Remedial
Action Target Area
Legend
Southwest Alluvium
• Idled Extraction Well
• Monitoring Well
a Water Level Monitoring Well
~ Dry Monitoring Well
Zone 3
¦ Idled Extraction Well Used for Monitoring
• Decommissioned or Idle Extraction Well
k Monitoring Well
• Dry or Decommissioned Monitoring Well
Zone 1
• Decommissioned Extraction Well
• Decommissioned Monitoring Well
• Monitoring Well
1.600
FIGURE 2
Site Layout arid Performance
Monitoring Well Locations,
2017 Operating Year
United Nuclear Corporation Church Rock Site,
Church Rock. New Mexico
HATCH
CHESTER
Figure 2: Site Layout
¦
—
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
iiimiiwmwimiiimim
North Cell /
Central Cell
SECTION 3
South
Southwest'AHuvium
SECTION 2
Figure 3: Extent of Seepage-Impacted Ground Water, October 2017
LEGEND
Section Boundary
¦iiimu Property Boundary
f.'J.j Tailings Pond
Groundwater with pH <= 4
Seepage-Impacted Groundwater
. rS
>W, Tt;
Aerial photo taken on
August 1, 1996.
SECTION 1
1,500
FIGURE 6
Hf
1 §2
i^nmuwoiwiwmiiaiimiiiwiiai
Extent of Seepage-Impacted
Groundwater, October 2017
United Nuclear Corporation Church Rock Site
Church Rock, New Mexico
SECTION 10
HATCH
CHESTER
3.000
UNC Church Rock Uranium Mill Superfund Site Fifth Five-Year Review
September 2018
-------
Figure 4: Southwest Alluvium Potentiometric Map, October 2017
Legend
• Southwest Alluvium Monitoring Well
Groundwater Elevation Contour
Inferred Groundwater Elevation Contour
..... Approximate Extent of Alluvium
- - - - Approximate Extent of Saturated Alluvium
¦maun property Boundary
Section Boundary
Cell Boundary
Notes:
1. Groundwater elevation values are
displayed in feet above mean sea level.
2. Well names are displayed with black
text.
3. Groundwater elevations are shown with
blue text and enclosed in parentheses
4. Aerial photo taken on August 1,1996.
5. NM - Not Measured
FIGURE 3A
Southwest Alluvium
Potentiometric Surface Map,
October 2017
United Nuclear Corporation Church Rock Site.
Church Rock, New Mexico
HATCH
CHESTER
UNC Church Rock Uranium Mill Superfund Site Fifth Five-Year Review
September 2018
-------
Figure 5: Southwest Alluvium Saturated Thickness Map, October 2017
0509 D
©Dj
Pipeline Arroyo —
Nickpoint- -1%
EPA 23
(620 3)
SECTION-!'
GW 3
(NM)
'GW2
(NM)*
tjL 0802
m 47>
.
nam q
GW 1
(17 S7h
SECTION 2
SBL-01
(1*81)
iCTlON 10
HATCH
CHESTER
Legend
• Southwest Alluvium Monitoring Well
—— Approximate Extent of Alluvium
- - - - Approximate Extant of Saturated Alluvium
¦hmhii Property Boundary
Section Boundary
Cell Boundary
Saturated Thickness Contours (feet)
Inferred Saturated Thickness Contours (feet)
Notes:
1. Well names are displayed with black
text.
2. Saturated thicknesses (feet) are shown
with blue text and enclosed in
parentheses.
3. Aerial photo taken on August 1, 1996.
4. The posted value of saturated thickness
at well 0509 D derives from reference to
the screen bottom. The alluvium
extends as much as 38 feet below this
depth in the vicinity of this well.
5. Saturated thickness at SBL-01
estimated due to incomplete well
construction information.
6. NM - Not Measured
0 250 500 1.000
FIGURE 3B
Southwest Alluvium
Saturated Thickness Map,
October 2017
United Nuclear Corporation Church Rode Site.
Church Rock. New Mexico
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Figure 6: Southwest Alluvium Water Levels, 1989-2017
w 6870
I
6820
////////////////////////"/////
Date
AHATCH
CHESTER
Figure 7: Southwest Alluvium Sulfate Concentrations, 1989-2017
—— Standard
———•Pumps Off
HATCH
CHESTER
]? 4000
cf
.2
Start of NA Test
Pumps Turned Off
January 2001
EPA22A
EPA 23
t EPA 25
-¦ EPA 27
EPA 28
GW1
GW2
—*— GW3
—¦*—GW4
*— SBL-01
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Pipeline Arroyo
Nickpoint
'SECTJON 3" --
0808
(1930)
[2820]
0802 X
' yjt (2M» -
V-0632 [2880]'
v' ^
f J^[3220)T $./ W
/ 0801
SECTION 2
i r \S2?PL
EPA 25
1(440)
-[1790]
GW1
<1*00%
[2550]]
SECTION 10 se£?1'
r,(tV2>.
5520]1
FIGURE 8
Southwest Alluvium Bicarbonate
Isoconcentration Map and
Distribution of Sulfate, October 2017
United Nuclear Corporation Church Rock Site.
Church Rock, New Mexico
HATCH
CHESTER
Legend
O Southwest ARuvlum Well
— — — Approximate Extent of Saturated Alluvium
——— Approximate Extent of AHuvium
Bicait>onate Isoconcentration
Contour In mg/L
Inferred Bicarbonate Isoconcentration
Contour in mg/L
Bicarbonate Concentrations (mg/L)
| 1000 -1500
B 1500 2000
>2000
— Property Boundary
Section Boundary
Tailings Pond
(25001 Bicarbonate result in mg/L
|2 lnoj Sulfate result In mg/L
1. Well names are displayed with black text.
2. Aerial photo taken on August 1.1996.
3. NS - Not Sampled
Figure 8: Southwest Alluvium Bicarbonate Isoconcentration Map, October 2017
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
~ 0509 D
0632
EPA 23
EPA 28
GW1
GW2
GW3
Standard
-——-Pumps Off
Figure 9a: Uranium Concentrations in Southwest Alluvium Wells (509 D and GW 3)
Start of NA Test
Pumps Turned Off
January 2001
H-3SS107
HATCH
CHESTER
¦ 0624
0627
—m—osoi
~ 0802
¦ 0803
— — — » Pumps Off
Q EPA 25
SBL-01
Figure 9b: Uranium Concentrations in Southwest Alluvium Wells
^ / J / / /" / V / ^ ^ f f f /
HATCH
_ ^ > CHESTER
H-3S5107
Start of HA Test
Pumps Turned Off
January 2001
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Figure 11: Effects of Past and Current Pumping to Dewater Zone 3
6930
6910
_ 6890
u>
£
6870
TO
>
11
v 6850
3
2 6830
6810
6790 -I
i i i I r i i
Jan-81 Jan-83 Jan-85 Jan-87 Jan-89 Jan-91 Jan-93 Jan-95 Jan-97 Jan-99 Jan-01 Jan-03 Jan-05 Jan-07 Jan-09 Jan-11 Jan-13 Jan-15 Jan-17
Date
0402
¦ 0504 B
¦0702
¦0711
¦EPA 09
MW-7
¦0420
-0517
-0706
¦0713
EPA 13
• Mine Water Discharge
"EPA 14 measuring point elevation adjustment applied as of Jan-13
H-355107
HATCH
CHESTER
UiTba- o' th» Matr* S»rur.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Figure 12: Zone 3 Approximate Extent of Seepage-impacted Ground Water, October 2017
_ _ !¦
N
i
Legend
¦ihihhi* Property Boundary
Zone 3 Target Remedial Action Area
Section Boundary
Cell Boundary
Approximate Area Impacted
by TaiHngs Seepage
Well Type
* Monitoring
4- Northernmost Pumping Wells
® Northernmost Pumping Wells (Off)
° Dry Monitoring
° Stage 1 Extraction
¦ Stage II Extraction
* Other Extraction Wells
* Plume Boundary
* Northeast Pump-Back
' Piezometer
Approximate Eastern Boundary
""""" of Zero Saturation
pH contour
Notes:
1. Well names are displayed with black text.
2. Values for field measured pH are shown with
purple text and enclosed In parentheses.
3. pH 3 contours omitted for figure clarity.
4. PB-02 not pumping during 2017.
5. Aerial pholo taken on August 1, 1996
0 200 400 800
Feet
FIGURE 35
Zone 3 Approximate Extent of Seepage
Impacts, October 2017
United Nuclear Corporation Church Rock Site.
Church Rock. New Mexico
JtJU HATCH
CHESTER
SECTION 36
XL:
Approximate Extant of Seepage
Impacts, 4th Quarter 2017
si" \ * /
.1- 1 I
* * ' ' ./?
0402 O
"V a|iS|-y //
^ !—Alluvium/Zone 3 Contact /o7ie/
\ * /ePA14#7
\ / *5.34) /
\ / ¦ / y
\ J 0716 / /
\ / / y'
\ / / /yfl617
\ •
\ x^om ora'
/ ° 4
• ¦bP&?tP . / oioa d 0613 yv
/ f2WW
.«• *s
North Cell ^ '7
/ 23 M-02
¦ —^J3 T ^
m, "j —
NW-3 " \»»' pMVM .»
»«« -/narv% - /
is«' >»'* ¦_ V'
"""
/ /' PB-04 ( !@3 i
V 0411/ ; I v *^£^0# A*->>--*
* V EPA 11 \
\ / * RW-A )_ O \
\ / 4« (5««; / \_ .
y Rw-11
/ <° 491 | Approximate EasternJBoundarvIof ¦ "
/ \ Zero Saturation. Octo^i^201.7^^-^fi't>:*
/ \ , ¦
y0420 0446 0 PP1„ .. .- yl ,
,24 f (fl 40) 0719 .-«*.~ O EPA 12
/ 0718 f3 27)*.% 0504 B
/ 5 " \"o720 ttV
^ \ ^
//¦ RW-18 V V—Region Desaturated
10717 * \ \ \ from tB89 to 2017
r09' * \ \ \
/ EPA 15 *»*" 0\ V I'
/ ° ° 0700 0712 1 T*#
/ 0707 \ I \ "JJKiljfl
D 0710 I 0713 1 \ ^ "* «• * "2lnB|
o 1 a 1 ^
r* °7", I ] ; V— Zone 3 Remedial Action Target Area
aB0> J / EpA 13 ^.
s 0706 ^,D y /
-------
Figure 13: Zone S Uranium, Vanadium, and Radionuclides Concentrations, 1989-2017
Zone 3 Uranium
^ -/ ^ J* J* ¦/"
—~—0009 D
H^»0106D
0411
0420
90
-•-0501 B
—~—0602 B
80
—~—0504 B
0518
70
—~—0613
0708
3 0711
0717
60
d
0719
£ 50
EPA 01
l 40
EPA 03
— EPA 06
——EPA 11
30
EPA 12
EPA 13
EPA 14
20
—M— EPA 15
—*— EPA 17
10
EPA 18
—— MW-6
Zone 3 Combined Radium
205.4
jti 1'
m 4, ^
K/% ?
/¦ /' /*
^ ^ ^ ^ ^
Data
Zone 3 Vanadium
f J* J" f **
Zone 3 Thorium-230
/ / f / / / / f / / / / /" / / —
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
MW-7
(0.0615)
MW-7
(0.0915)
Background Uranium
UPL95 = 0.395 mg/L
Range of 0.0007 - 0.38
mg/L
NBL-02
(0.235)
NBL-02
(0.235)
¥ PB-03
<0 107)'
\_ PB-04
PB-02 (0.535)'
PB-02 (0 535V
Approximate Extent of Seepage
Impacts. 4th Quarter 2017
Approximate Extent of Seepage^
Impacts. 4th Quarter 2017
-------
Figure IS: Zone 1 Potentiometric Surface Map, October 2017
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Figure 16: Zone 1 Extent of Seepage Impacts, October 2017
0502 A
0505 A
• 0501 A
.HUMP' jj
SECTION 36
EPA 02
EPA 07
/233/
(6.09)
0515 A
[364]
1 .jPp
'£gB&2p
ja&S».3si
*' pSes? •-:;; - »¦
As: fthS - rlt
L *^vKKHlKK?^n«HE
-
¦
\
\
Section 36
\
\
\
*
\
Section 3
/4^-
Section 2
Section 1
Section 10
0
0.5
1
Miles
Legend
Well Type
Water Quality and Water
° Level Monitoring
® Water Level Monitoring
© Decomissioned East Pump Back
Revised East Pump
^ Back (Inactive)
Cell Boundary
¦man Property Boundary
___ Approximate Extent of Zone 1
I Seepage Impact
Approximate Extent of Zone 1
pH Less Than 4.0
[36] Chloride result in mg/L
(6 29) Field-measured pH in SU
Notes:
1. Seepage impacts delineated by
chloride detections greater than 50
mg/L.
2. Aerial photo taken on August 1,
1996.
250
500
Feet
1,000
FIGURE 48
Zone 1 Extent of Seepage Impacts,
October 2017
United Nuclear Corporation Church Rock Site,
Church Rock. New Mexico
—
<&>
HATCH
CHESTER
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Figure 17: Zone 3 Proposed Sentinel Monitoring Well Locations, October 2017
Ntu.
£ \
&¦
L-
SECTION 36
'jP'iVf,...
/Mf
2y'-'{$$1 ijjjf . / r.
MfriV. ¦ES&SraV. I/ /
lUfr8'*, )/*". *( v
• ,/ Mi
Boundary Well
Piezometer Installed In 2004
Extraction Well
Extraction WeH (Off)
Former Extraction Wefl
Proposed Monrtonng Well
Proposed Monitoring Well Pair
• Property Boundary
- Zone 3 Target Remedial Action Area
- Section Boundary
- Cefl Boundary
Approximate Eastern Boundary
* of Zero Saturation
Approximate Area Impacted
Seepage Plume by Taaings seepe^e
Notes:
1 Aerial photo taken on August 1,1996.
SW-2B
FIGURE B-2
Zone 3 Proposed
Monitoring Well Locations
United Nuclear Corporation Church Rock Site,
Church Rock, New Mexico
HATCH
CHESTER
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
APPENDICES
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
APPENDIX A
SITE INSPECTION CHECKLIST
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
Site Inspection Checklist
1. SITE INFORMATION
Site name: United Nuclear
Corporation
Date of inspection: October 31, 2017
Location and Region:
McKinley County, New Mexico,
EPA R6
EPA ID:
NMD030443303
Agency, office, or company leading
the five-year review:
New Mexico Environment
Department (NMED)
Weather/temperature:
Partly cloudy, breezy, low 60's
Remedy Includes: (Check all that apply)
Landfill cover/containment XX Monitored natural attenuation
XX Access controls XX Groundwater containment
XX Institutional controls Vertical barrier walls
XX Groundwater pump and treatment
XX Surface water collection and treatment
Other
Attachments: X Inspection team roster attached Site map attached
II. INTERVIEWS (Check all that apply)
1. O&M site manager RickvSDitz (AMEC Foster Wheeler) Proiect manager
10/31/2017
Name Title
Interviewed: XX at site at office by phone Phone no.
Problems, suggestions
Date
2. O&M staff
Name Title
Interviewed at site at office bv phone Phone no.
Date
Problems, suggestions;
3. RD/RA consultant
Name Title
Interviewed at site at office by phone Phone no.
Date
Problems; suggestions:
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
4.
Local regulatory authorities and response agencies (i.e., State and Tribal offices, emergency '
response office, police department, office of public health or environmental health, zoning office,
recorder of deeds, or other city and county offices, etc.) Fill in all that apply.
Agency NM Environment Department
Contact Steve Jetter Project Manager _
Name Title Date
Problems; suggestions;
505-827-0072
Phone no.
Not interviewed since person is an author of the 2018 UNC Five Year Review Report
Agency Navajo Nation Superfund Program
Contact Binod Chaudharv Sr Environmental Engineer 928-871-7820
Name Title Date Phone no.
Problems; suggestions; Report attached See Interview Record from Navajo Nation
Agency _
Contact
Name
Problems; suggestions;
Title
Date
Phone no.
Agency_
Contact
Name
Problems; suggestions;
Title
Date
Phone no.
Other interviews (optional)
Interviews with community members were held at the Coyote Canyon and Pinedale Chapter Houses of
the Navajo Nation (See Interview Records)
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
-------
III. ON-SITE DOCUMENTS & RECORDS VERIFIED (Check all that apply)
1.
O&M Documents
O&M manual XX Readily available Up to date N/A
As-built drawings XX Readily available Up to date N/A
Maintenance Jogs Readily available Up to date XX N/A
Remarks: UNC has all available documentation in the office and it is kept up to date.
All Annual Review Reports From 1999-2016 on site and show maps of wells in each zone and
facilitv features.
2.
Site-Specific Health and Safety Plan XX Readily available X Up to date . N/A
Contingency plan/emergency response plan XX Readily available X Up to date N/A
Remarks: On-site in Health and Safetv Binder / NECR IRA 2009
3.
O&M and OSHA Training Records XX Readily available XX Up to date N/A
Remarks: Records available online
4.
Permits and Service Agreements
Air discharge permit • Readily available Up to date XX N/A
Effluent discharge Readily available Up to date XX N/A
Waste disposal, POTW Readily available Up to date XX N/A
Other permits XX XX Readilv available XX Up to date N/A
Remarks: NRC Source Material License SUA 1475
5.
Gas Generation Records Readily available Up to date XX N/A
Remarks:
6.
Settlement Monument Records Readily available Up to date XX N/A
Remarks:
7.
Groundwater Monitoring Records XX Readily available Up to date N/A
Remarks: Annual reports kept on site and delivered to regulatorv agencies in timelv manner.
8.
Leachate Extraction Records XX Readily available Up to date N/A
Remarks: The remedv is not reallv classified for leachate extraction. However, the groundwater
extraction remedv removes seepage impacted groundwater from the tailing disposal. Currently
onlvthe Zone 3 svstem is operating. Information is reported in each annual report.
9.
Discharge Compliance Records
Air Readily available Up to date N/A
Water (effluent) Readily available Up to date XX N/A
Remarks
UNC Church Rock Uranium Mill Superfund Site
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10. Daily Access/Security Logs XX Readily available XX Up to date N/A
Remarks: UNC Site contractor AMEC Foster Wheeler maintains daily on site presence during the
work week. Staff patrol site regularly and check access gate locks and fences. Monitor site .
access and visitors must sign in at office in log book.
IV. O&M COSTS
1. O&M Organization
State in-house Contractor for State
PRP in-house XX Contractor for PRP
Federal Facility in-house Contractor for Federal Facility
Other
2. O&M Cost Records
Readily available Up to date
Funding mechanism/agreement in place
Original O&M cost estimate
Total annual cost by year for review period
From To. . Breakdown attached
From
Date
To
Date
Total cost
Breakdown attached
From
Date
To
Date
Total cost
Breakdown attached
From
Date
To
Date
Total cost
Breakdown attached
From
Date
To
Date
Total cost
• Breakdown attached
Date
Date
Total cost
3. Unanticipated or Unusually High O&M Costs During Review Period
Describe costs and reasons:
None identified
V. ACCESS AND INSTITUTIONAL CONTROLS Applicable N/A
A. Fencing
1. Fencing damaged Location shown on site map XX Gates secured , N/A
Remarks: Fences are in place and properly maintained and inspected weekly. Special attention is
given after rain events. Gates are closed and secured with chains and locks.
UNC Church Rock Uranium Mill Superfund Site
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B. Other Access Restrictions
1. Signs and other security measures Location shown on site map N/A
Remarks: Radiation danger and No Trespassing signs are visibly posted on fences and at gate
entrances. Monthly inspections performed.
c.
Institutional Controls (ICs)
1.
Implementation and enforcement
Site conditions imply ICs not properly implemented Yes
Site conditions imply ICs not being fully enforced Yes
Type of monitoring (e.g., self-reporting, drive by)
Frequency
No N/A
No N/A
Responsible party/agency
Contact
Name Title
Date
Phone no.
Reporting is up-to-date Yes No N/A
Reports are verified by the lead agency Yes No N/A
Specific requirements in deed or decision documents have been met Yes ¦ No N/A
Violations have been reported Yes No N/A
Other problems or suggestions: Report attached
2.
Adequacy ICs are adequate ICs are inadequate
Remarks
N/A
D.
General
1.
Vandalism/trespassing Location shown on site map No vandalism evident
Remarks
2.
Land use changes on site N/A
Remarks: No land use changes during this reporting period
3.
Land use changes off site N/A
Remarks: None
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VI.
GENERAL SITE CONDITIONS
A. Roads Applicable
N/A
1. Roads damaged
Remarks .
Location shown on site map
XX Roads adequate N/A
B. Other Site Conditions
Remarks:
VII. LANDFILL COVERS Applicable XX N/A
A.
Landfill Surface
1.
Settlement (Low spots)
Areal extent
Remarks
Location shown on site map Settlement not evident
Depth
2.
Cracks
Lengths
Location shown on site map Cracking not evident
Widths Depths
Remarks.
1
3.
Erosion
Areal extent
Remarks
Location shown on site map Erosion not evident
Depth
4.
Holes
Areal extent
Remarks
Location shown on site map Holes not evident
Depth
5.
Vegetative Cover Grass Cover properly established No signs of stress
Trees/Shrubs (indicate size and locations on a diagram) .
Remarks
6.
Alternative Cover (armored rock, concrete, etc.) N/A
Remarks
UNC Church Rock Uranium Mill Superfund Site
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7.
Bulges Location shown on site map
Areal extent Height
Remarks
Bulges not evident
8.
Wet Areas/Water Damage Wet areas/water damage not evident
Wet areas Location shown on site map
Areal
extent
Ponding Location shown on site map
Areal
extent
Seeps Location shown on site map
Areal
extent
Softsubgrade . Location shown on site map
Areal extent
Remarks
9.
Slope Instability Slides Location shown on site map
Areal extent
Remarks
No evidence of slope instability
B.
Benches Applicable X N/A
(Horizontally constructed mounds of earth placed across a steep landfill side slope to interrupt
the slope in order to slow down the velocity of surface runoff and intercept and convey the
runoff to a lined channel.)
1.
Flows Bypass Bench Location shown on site map
Remarks
N/A or okay
2.
Bench Breached Location shown on site map
Remarks
N/A or okay
3.
Bench Overtopped Location shown on site map
Remarks
N/A or okay
C.
Letdown Channels Applicable X N/A
(Channel lined with erosion control mats, riprap, grout bags, or gabions that descend down the
steep side slope of the cover and will allow the runoff water collected by the benches to move
off of the landfill cover without creating erosion gullies.)
1.
Settlement Location shown on site map No evidence of settlement
Areal extent Depth
Remarks
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2.
Material Degradation Location shown on site map No evidence of degradation
Material tvoe Area 1 extent
Remarks
3.
Erosion Location shown on site map No evidence of erosion
Areal extent DeDth
Remarks
4.'
Undercutting Location shown on site map No evidence of undercutting
Areal extent DeDth
Remarks
5.
Obstructions Tvoe No obstructions
Location shown on site mao Areal extent
Size
Remarks
6.
Excessive Vegetative Growth Tvoe
No evidence of excessive growth
Vegetation in channels does not obstruct flow
Location shown on site mao Areal extent
Remarks
D.
Cover Penetrations Applicable X N/A
1.
Gas Vents Active Passive
Properly secured/locked Functioning Routinely sampled Good condition .
Evidence of leakage at penetration Needs Maintenance N/A
Remarks
2.
Gas Monitoring Probes
Properly secured/locked Functioning Routinely sampled Good condition
Evidence of leakage at penetration Needs Maintenance N/A
Remarks
¦
3.
Monitoring Wells (within surface area of landfill)
Properly secured/locked Functioning Routinely sampled Good condition
Evidence of leakage at penetration Needs Maintenance N/A
Remarks
4.
Leachate Extraction Wells
Properly secured/locked Functioning Routinely sampled Good condition
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E. Gas Collection and Treatment Applicable X N/A
1. Gas Treatment Facilities
Flaring Thermal destruction Collection for reuse
Good condition Needs Maintenance
Remarks
2. Gas Collection Wells, Manifolds and Piping
Good condition Needs Maintenance
Remarks
3. Gas Monitoring Facilities (e.g., gas monitoring of adjacent homes or buildings)
Good condition Needs Maintenance N/A
Remarks
F.
Cover Drainage Layer
Applicable
XN/A
1.
Outlet Pipes Inspected
Remarks
Functioning
N/A
2.
Outlet Rock Inspected
Remarks
Functioning
N/A
G. Detention/Sedimentation Ponds Applicable X N/A
1. Siltation Areal extent Depth N/A
Siltation not evident
Remarks
2. Erosion Areal extent Depth
Erosion not evident
Evidence of leakage at penetration
Remarks
Needs Maintenance
N/A
5.
Settlement Monuments Located
Remarks
Routinely surveyed
N/A
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Remarks
3. Outlet Works
Remarks
Functioning N/A
4. Dam
Remarks
Functioning N/A
H. Retaining Walls
Applicable
XN/A
1. Deformations
Horizontal displacement
Location shown on site map Deformation not evident
Vertical displacement
Rotational displacement
Remarks
¦
2. Degradation
Remarks
Location shown on site map .
Degradation not evident
1. Perimeter Ditches/Off-Site Discharge Applicable
XN/A.
1. Siltation
Areal extent
Location shown on site map
Deoth
Siltation not evident.
Remarks
-
2. Vegetative Growth
Areal extent
Location shown on site map
Tvoe
N/A < Vegetation does not impede
flow
Remarks
3. Erosion
Areal extent
Location shown on site map
Depth
Erosion not evident
Remarks
4. Discharge Structure
Remarks
Functioning N/A
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VIII. VERTICAL BARRIER WALLS Applicable X N/A
1.
Settlement Location shown on site map Settlement not evident
Areal extent Depth
Remarks
2.
Performance MonitoringTvoe of monitoring Performance hot monitored
Freauencv Evidence of breaching
Head differential
Remarks
IX. GROUNDWATER/SURFACE WATER REMEDIES XX Applicable N/A
A.
Groundwater Extraction Wells, Pumps, and Pipelines XX Applicable N/A
1.
Pumps, Wellhead Plumbing, and Electrical
Good condition All required wells properly operating Needs Maintenance N/A
Remarks: Onlv Zone 3 extraction wells are operational. Zone 3 consists of 6 extraction wells
currently pumping at <0.5 gpm and well vields continue to decrease from approx. 2.3 gpm in
2013 to approx. 1.4gpm in 2017. Pumps and wells reauire frequent maintenance.
SWA extraction remedv was switched to natural attenuation and Zone 1 remedv
decommissioned (1999) with regulatory agencv approval.
2.
Extraction System Pipelines, Valves, Valve Boxes, and Other Appurtenances
XX_ Good condition Needs Maintenance
Remarks: Eauipment is maintained in good working condition.
3.
Spare Parts and Equipment
XX Readily available Good condition Requires upgrade Needs to be provided
Remarks: Spare pumps, piping, valves stored at on-site office.
B. Surface Water Collection Structures, Pumps, and Pipelines Applicable XX N/A
1. Collection Structures, Pumps, and Electrical
UNC Church Rock Uranium Mill Superfund Site Fifth Five-Year Review
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Good condition Needs Maintenance
Remarks
2.
Surface Water Collection System Pipelines, Valves, Valve Boxes, and Other Appurtenances
Good condition Needs Maintenance
Remarks
3.
Spare Parts and Equipment
Readily available Good condition Requires upgrade Needs to be provided
Remarks
C.
Treatment System XX Applicable N/A
1.
Treatment Train (Check components that apply)
Metals removal Oil/water separation Bioremediation
Air stripping Carbon adsorbers
Filters
Additive (e.g., chelation agent, .
flocculent)
Others: Extracted water treated through evaporation in two on-site oonds
XX Good condition Needs Maintenance
Sampling ports properly marked and functional
Sampling/maintenance log displayed and up to date
XX Equipment properly identified
Quantity of groundwater treated annuallv: 988,000 gals (2014) and 619,000 gals (2017)
Quantity of surface water treated annually
Remarks: Annual oumoing volumes are decreasing due to decreased saturated thickness of the
aauifers.
2.
Electrical Enclosures and Panels (properly rated and functional)
N/A XX Good condition Needs Maintenance
Remarks
3.
Tanks, Vaults, Storage Vessels
XX N/A Good condition Proper secondary containment Needs Maintenance
Remarks
4.
Discharge Structure and Appurtenances
N/A XX Good condition Needs Maintenance
Remarks Water is treated in two large evaporation ponds. The oonds are wav oversized for
current pumping rates/volumes. To maintain the liners from deterioration from exposure to sun
UNC Church Rock Uranium Mill Superfund Site
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and weather, supplemental water from the on-site domestic well is used to fill the ponds
5.
Treatment Building(s)
XX N/A Good condition (esp. roof and doorways) Needs repair
Chemicals and equipment properly stored
Remarks
6.
Monitoring Wells (pump and treatment remedy)
XX Properly secured/locked XX Functioning XX Routinely sampled XX Good condition
All required wells located Needs Maintenance N/A
Remarks SWA wells GW-2 and GW-3 are to close to the Pipeline Arroyo embankments to
be sampled safelv. These wells have not been sampled since 2015. Additional Zone 3 sentinel
wells have been proposed for placement on Navaio Nation land, but have not been installed,
since the permitting process has not been completed vet.
D. Monitoring Data
1.
Monitoring Data
XX Is routinely submitted on time XX Is of acceptable quality
2.
Monitoring data suggests:
XX Groundwater plume is effectively contained XX Contaminant concentrations are declining
D.
Monitored Natural Attenuation J(X Applicable NA
1.
Monitoring Wells (natural attenuation remedy)
XX Properly secured/locked " XX Functioning XX Routinely sampled
XX Good condition All required wells located Needs Maintenance N/A
Remarks: Natural attenuation of metals and radionuclide is occurring in all three aauifer zones
based on declining trends historically. However, for Zone 3. the NA rate is not high enough to
overcome natural ground water flow gradient controlled by the stratigraphic dip and plume
continues to migrate to the north.
X.
OTHER REMEDIES
If there are remedies applied at the site which are not covered above, attach an inspection sheet
describing the physical nature and condition of any facility associated with the remedy. An
example would be soil vapor extraction.
XI. OVERALL OBSERVATIONS
A.
Implementation of the Remedy
Describe issues and observations relating to whether the remedy is effective and functioning as
UNC Church Rock Uranium Mill Superfund Site
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designed. Begin with a brief statement of what the remedy is to accomplish (i.e., to contain
contaminant plume, minimize infiltration and gas emission, etc.).
See Interview Record with Roy Blickwedel (GE) and Annual Monitoring Reports for details on
effectiveness of the remedy.
B. Adequacy of O&M
Describe issues and observations related to the implementation and scope of O&M procedures.
In particular, discuss their relationship to the current and long-term protectiveness of the
remedy.
O&M measures for the Zone 3 extraction system is adequate but thev do not affect the current
or long term protectiveness of the remedy. The monitoring well network/program for all 3 zones
is adequate for establishing concentration trends and plume migration. Additional sentinel wells
have been proposed for Zone 3 on Navaio Nation land north to support the groundwater model
and plume migration but those well have not been installed to date.
c.
Early Indicators of Potential Remedy Problems
Describe issues and observations such as unexpected changes in the cost or scope of O&M or a
high frequency of unscheduled repairs that suggest that the protectiveness of the remedy may
be compromised in the future.
None. The remedy has performed as well as expected in the ROD.
D. Opportunities for Optimization
Describe possible opportunities for optimization in monitoring tasks or the operation of the
remedy.
See Interview Record with Rov Blickwedel (GE)
UNC Church Rock Uranium Mill Superfund Site
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APPENDIX B
SITE CHRONOLOGY
UNC Church Rock Uranium Mill Superfund Site
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Chronology of Events for UNC and NECR Sites
Event
Date
UNC and Kerr McGee receive National Pollution Discharge Elimination Permits (NPDES) to
release mine water to unnamed arroyo leading to Pipeline Canyon Arroyo.
January 1975
EPA 906/9/9-75-002 report released documenting NECR Mine discharge water elevated in
radium & uranium above NPDES limits.
September 1975
UNC milling operations begin under license from the State of New Mexico
Radiation Protection Bureau.
June 1977
Retention dam on UNC south tailings disposal cell breached & released an estimated 93
million gallons of acidic mill tailings water and sediment to Pipeline Canyon / Rio Puerco
River. EPA Region 6 and NMEID respond to contaminant release.
July 1979
NMEID orders UNC to perform cleanup of Rio Puerco contaminated areas to 3 pCi/g of Ra-
226, Th-230, & Pb-210 where possible.
August 13,1979
NMEID orders UNC to implement discharge plan to control contaminated tailings seepage
November 9,1979
UNC sampled off site monitor well TWQ-124 & results indicated that Th-230 level
exceeded NM Radiation Protection Regulations beyond the restricted area of the licensed
facility. Other non-radiological constituents were degrading off site ground water quality.
October 28,1980
EPA begins discussions with UNC over the need for a ground water investigation of
tailings seepage from mill site that follows the CERCLA Process (Comprehensive,
Environmental Response, Compensation and Liability Act or Superfund Act of 1980).
February 19,1982
EPA informs UNC that the mill site has been placed oh Interim Priority List for hazard
ranking analysis, a measure that is used in the process to consider a site for the National
Priority List (NPL) or Superfund. UNC milling operations begin under license from State of
New Mexico Radiation Protection Bureau.
April 2,1982
UNC announces mill closing due to depressed uranium market.
May 1982
EPA provides UNC with final Administrative Order on Consent (AOC) developed in
coordination with NMEID. UNC did not sign the AOC.
November 8,1982
EPA performs Field Investigation Team (FIT) inspection sampling of tailings solution,
surface water, and ground water at UNC Site.
November 8 & 15,1982
UNC mill site placed on the National Priorities List (NPL) of Superfund Sites due to off-site
migration of radionuclides and chemical constituents in ground water.
1983
EPA conducts Remedial Investigation (Rl) field activities to determine the nature& extent
of ground water contamination in the three water-bearing formations at the Site.
March 1984 - August 1987
In 1984, UNC blocked EPA access to the Church Rock facility, and EPA brought an action to
compel site access. UNC counterclaimed seeking declaratory and injunctive relief. U.S.
District Court granted an EPA motion to dismiss the UNC counterclaims, &UNC provided
access to the Site to EPA. United States v. United Nuclear Corporation, 610 F Supp. 527,
528 (D.N.M., 1985).
April 18,1985 •
NMEID returns Uranium Mill Tailings Radiation Control Act (UMTRCA) federal regulatory
program to the U.S. Nuclear Regulatory Commission (NRC).
June 1986
UNC Church Rock Uranium Mill Superfund Site
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Chronology of Events for UIMC and NECR Sites
Event
Date
EPA and NRC sign Memorandum of Understanding (MOU) coordinating EPA'sCERCLA
ground water remedial action with NRC's reclamation & closure activities under the
Source Materials License and UMTRCA for Title II sites.
August 26,1988
EPA releases Rl and Feasibility Study (FS) report along with proposed plan of action
field sheet.
August 1988
EPA issues a Record of Decision (ROD) describing the remedy to address UNC
contaminated water beyond the boundaries of the tailings disposal cells by extraction-
evaporation of ground water.
September 30,1988
UNC submits Remedial Design Report.
April 1989
Remedial action implemented in Zone 1 - Borrow Pit No. 2 dewatered.
April 1989
EPA issues Unilateral Administrative Order (UAO) Docket No. CERCLA 6-11-89 to UNC
requiring UNC to implement the Site CERCLA ground water operable unit remedy
determined by the ROD.
June 29,1989
Remedial action implemented in Zone 3-12 new extraction wells begin pumping.
August 1989
Remedial action implemented in Southwest Alluvium - 3 new extraction wells begin
pumping.
October 1989
Ground Water Corrective Action Annual Review 1989 documents remedial action
construction completion.
December 1989
United States had brought action against UNC in 1991 for response cost recovery under
CERCLA; and in late 1992, the U.S. District Court issued an opinion and order granting a
U.S. motion for partial summary judgment on the issue of costs and denying a UNC cross
motion for summary judgment. United States v. United Nuclear Corporation, 814 F Supp.
1552 (D.N.M„ 1992).
December 28,1992 .
NRC issues a background water quality study that recommends higher concentrations of
background constituents than presented in the ROD.
1996
First Five-Year Review completed.
September 24,1998
NRC, EPA, and NMED approve the decommissioning often Zone 3 wells, three Zone
1 wells, and one Southwest Alluvium well because they meet the decommissioning
criteria of producing less than 1 gallonper minute (gpm).
July 30,1999
NRC approves eliminating the Section 1 portion of Zone 3 as a point of exposure.
September 16,1999
UNC submits request to terminate all Zone 3 pumping and for Technical Impracticability
waiver to EPA, NRC and NMED.
May 2000
All but three Zone 3 wells decommissioned in accordance with criterion.
June 2000
EPA approves UNC's request to shut down remaining three Zone 3 wells to slow seepage
migration rate.
November 2000
UNC Church Rock Uranium Mill Superfund Site
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Chronology of Events for UNC and NECR Sites
Event
Date
License Amendment No. 31 allows UNC to temporarily suspend the corrective action
pumping in Zone 3.
December 29, 2000
License Amendment No. 32 approves the conversion of the Zone 3 Phase II extraction
wells to monitoring wells.
March 8, 2001
UNCsubmits DraftTribal Resolution and Environmental Right-of-Way to the Navajo
Nation to form basis for ICs.
March 2001
EPA gives UNC approval to temporarily shut down Southwest Alluvium extraction wells
and an 18-month Natural Attenuation Test is conducted.
February 2001 - July 2002
UNC submits Final Report and Technical Impracticability Evaluation - Southwest Alluvium
Natural Attenuation Test to EPA, NRC and NMED.
November 2002
UNC submits proposal to conduct hydraulic fracturing pilot test.
May 21, 2003
UNC conducts the hydraulic fracturing pilot test in Zone 3.
June 2003
Second Five-Year Review completed.
September 18, 2003
UNCsubmits Final Report - Hydraulic Fracturing Pilot Test Results and Preliminary Full-
Scale Design, United Nuclear Church Rock Facility.
December 2003
EPA comments on the Final Report - Hydraulic Fracturing Pilot Test Results and
Preliminary Full-Scale Design and directs UNC to perform supplemental feasibility study
(SFS) for Zone 3.
March 10, 2004 and
March 19, 2004
EPA approves Final Report - Hydraulic Fracturing Pilot Test Results and Preliminary Full-
Scale Design.
May 21, 2004
UNC conducts the Phase 1 full-scale hydraulic fracturing test in Zone 3.
September 2004
UNC installs well SBL-01 in Section 10, Southwest Alluvium.
October 2004
UNC submits the draft SFS for Zone 3 for review.
October 27, 2004
EPA disapproves draft SFS for Zone 3 and directs UNC to perform a Site-wide SFS (SWSFS)-
consistent with the NCP.
June 24, 2005
Meeting between EPA, UNC, NRC, NMED,.and NNEPA to discuss the SWSFS. UNC generally
expresses its opposition to the feasibility study process.
August 17, 2006
Meeting between EPA, NNEPA, BIA and NMED in Window Rock, AZ, to discuss feasibility
of ICs restricting the use of contaminated ground water.
January 18, 2006
Meeting between EPA and NNEPA in Dallas, TX, to continue discussions on ICs.
March 16, 2006
EPA approves in-situ alkalinity stabilization pilot study for Zone 3.
May 12, 2006
EPA directs UNC to perform the SWSFS in writing, stating that the feasibility study is
appropriate and necessary.
June 23, 2006
Meeting between EPA, NNEPA, BIA, and NMED in Albuquerque, NM to continue
discussions on ICs.
August 21, 2006
UNC Church Rock Uranium Mill Superfund Site
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Chronology of Events for UNC and NECR Sites
Event
Date
UNC submits the draft List of Preliminary Assembled Remedial Alternatives for the SWSFS.
September 2006
UNC begins the in-situ alkalinity stabilization pilot study in Zone 3. The study is completed
in February 2007.
October 2006
UNC submits the draft SWSFS, Part 1, Church Rock Remediation Standards Update.
February 2007 , .
UNC submits In-Situ Alkalinity Stabilization Pilot Study Report.
June 2007
EPA disapproves SWSFS, Part 1, Church Rock Remediation Standards Update and requires
revision to address written comments.
January 25, 2008
Meeting between EPA, NMED, NRC, NNEPA and UNC to discuss status of remedial
activities. UNC notifies regulatory agencies that pumping of hydraulic fracture wells in
Zone 3 was unsuccessful in stopping migration of seepage-impacted ground water. UNC
proposes to submit a plan for additional extraction wells for Zone 3.
March 12, 2008
UNC submits summary of hydrogeologic analysis evaluation of ground water flow and
recommended plan for additional extraction wells for interception and recovery of
seepage-impacted ground water in Zone 3.
April 2008
UNC submits white paper on statistics to address some of EPA comments on the SWSFS,
Part 1.
May 2008
EPA notifies NRC of approval of UNC's recommendation for additional extraction wells.
June 2008
UNC installs five new extraction wells (the NW-series) in northern Zone 3.
September 2008
Third Five Year Review completed.
Septembe.r 17, 2008
UNC submits calculation of background statistics with comparison values.
October 2008
UNC submits calculation of estimated UCL95 statistics and exposure point concentrations
in impacted groundwater. UNC submits to NRC an alternate concentration limits
application for Zone 1.
December 2008
Pumping of the NW-series of extraction wells in northern Zone 3 begins. Later in the year
the pumping scheme was reorganized to include three of the five wells.
February 2009 and November
2009
EPA accepts revised SWSFS Part 1, Remediation Standards Update and gives approval for
UNC to proceed with SWSFS Part II: Development and Screening of Remedial Alternatives.
February 11, 2009
EPA Region 6 conducts community meeting at Pinedale Chapter House to give an update
on the UNC 2008 Five Year Review.
May 5, 2009
UNC-GE letter to NRC on Technical Impediments to Site Closure at the Church Rock Mill
Site (lack of consensus, unattainable cleanup standards, & complex issues related to
statistics and geochemistry).
May 20, 2009
EPA Region 9 releases Northeast Church Rock (NECR) Engineering Evaluation/Cost Analysis
(EE/CA) report for non-critical time removal of NECR mine waste. The preferred alternative
for disposition of NECR Mine waste is disposal at an NRC-licensed facility, namely the UNC ,
Mill Site tailings disposal ponds.
June 11, 2009
UNC submits revised Site-Wide Supplemental Feasibility Study Part II.
July 2009
UNC Church Rock Uranium Mill Superfund Site
September 2018
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Chronology of Events for UNC and NECR Sites
Event
Date
UNC submits hydrogeologic analysis of recent Zone 3 injection testing (new background
well NBL-2) in northern Zone 3 and proposal to enhance remediation using one or more
injection wells amended with sodium bicarbonate
December 2009
UNC proposes the location for a pilot injection well in Zone 3.
April 2010
UNC submits report entitled, The Remedial Design: Conceptual Approach to Enhanced
Remediation in Zone 3-New Injection Wells combined with Existing Extraction Wells.
May 17, 2010
UNC submits a hydrogeologic analysis of injection testing of Zone 3 well IW-A during July
2010.
August 2010
UNC-GE submits NRC License SUA-1475 Amendment request for revised dates to complete
ground water corrective actions (12-31-2013) and to install final radon barrier and erosion
protection cover on tailings pond (12-31-2014).
September 1, 2010
EPA provides UNC-GE with combined agency comment-approval letter (EPA, NRC, NMED,
NNEPA) on SWSFS Part II dated July 2009, and general considerations-requirements to
proceed with Part III
September 2, 2010
UNC submits revised version of the Updated Baseline Human Health Risk Assessment.
March 4, 2011
UNC starts injection at well IW-A of site Mill well water amended with alkalinity (sodium
bicarbonate.
April 14, 2011
UNC submits revised versions of SWSFS Part 1 and Part II.
April 26, 2011
EPA issues a comment letter on the draft updated human health risk assessment
July 2011
UNC submits a technical memorandum summarizing two previously submitted reports on.
Zone 3 tailings seepage sourcing and groundwater recharge, with an information update.
August 2011
EPA Region 9 provides regional assessment report on ground water quality in/around
UNC-NECR Mill facilities
September 2011
EPA issues comment letter on the Site-Wide Supplemental Feasibility Study Part II (July
2009) (in fact, this comment letter addressed Parts 1, II, and III).
October 2011
UNC submits provisional responses to EPA comment letter (July 2011) on the draft
baseline human health risk assessment (March 2011).
October 2011
UNC provides report on the Hydrogeologic Assessment of Injection at Zone 3 Well IW-A
through September 2011 to EPA and NRC.
November 1, 2011
UNC submits a document requesting discussion and clarification about the EPA comment
letter (October 14, 2011) addressing revised Site-Wide Supplemental Feasibility Study
Parts 1 and II (April 2011).
November 2011
By email, UNC provides all agency stakeholders with revisions to the draft updated human
health risk assessment (March 2011).
February 2012
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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Chronology of Events for UNC and NECR Sites
Event
Date
EPA risk assessment specialist provides UNC with comments (by email) on the revised
draft updated human health risk assessment (February 2012). Follow-up phone discussion
between EPA risk specialist and UNC on April 27, 2012
March 2012
GE submits to NRC a license amendment request for revised groundwater protection
standards based on updated background concentrations (statistically calculated
background threshold values). The three site hydrostratigraphic units are addressed
individually.
April 2012
• UNC submits to NRC, "License Amendment Request Revised Ground Water Protection
Standards Based on Updated Background Concentrations Source Material License SUA-
1475 Ground Water Corrective Action Program United Nuclear Corporation Church Rock
Tailings Site."
April 21, 2012
UNC presents the numeric groundwater hydraulic modeling (with focus on Zone 3) to all
agency stakeholders at the annual technical meeting in Albuquerque.
May 14, 2012
UNC submits to EPA: "Overview of Draft Attached Tables, Summary Comparisons of Upper
Prediction Limits for Parameter Concentrations in Background Groundwater to Site
Cleanup Standards and Potential ARARs for All Three Hydrostratigraphic Units at the
Church Rock Mill Tailings Site."
June 2012
UNC provides final version of the Updated Baseline Human Health Risk Assessment for the
Church Rock Site in order, to: 1) update risk estimates for the Site using current risk
assessment methods-information; 2) support reassessment of remediation levels; 3)
compare remedial alternatives; & 4) identify Point of Compliance (POC) & Point of
Exposure (POE) concentrations in accordance with NRC requirements.
August 2012
EPA Region 6 provides UNC with acceptance letter for Updated Baseline Human Health
Risk Assessment (August 13, 2012 version).
September 11, 2012
UNC notifies the agencies that injection of sodium bicarbonate-amended water, in Zone 3
well IW-A, was terminated on June 29, 2012.
October 2012
UNC provides ground water flow model report of the Church Rock Site & local area for
three genetic classes of ground water to support decision-making for future Zone 3 ACL
October 2012
EPA issues Record of Decision (ROD) for the Site Surface Soil Operable Unit Alternative 2
preference for disposal of NECR mine waste at UNC Mill Site tailings evaporation ponds
under NRC license SUA-1475.
March 2013
EPA Office of Research and Development (ORD) issues technical memorandum on the
background ground water conditions in the SWA and Zones 1 and 3 of UNC Site and the
proposed cleanup and compliance monitoring levels for COPCs using the statistically-
based 95 percent upper prediction limits (UPL95s) (also known as "Overview of Draft
Attached Tables, Summary Comparisons of Upper Prediction Limits for Parameter
Concentrations in Background Groundwater to Site Cleanup Standards and Potential
ARARs for All Three Hydrostratigraphic Units at the Church Rock Mill Tailings Site.").
March 2013
DOE issues comments to NRC regarding the April 2012 UNC License Amendment Request
for Revised Groundwater Protection Standards Based on Updated Background
Concentrations.
April 2013
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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Chronology of Events for UNC and NECR Sites
Event
Date
NRC issues response to DOE comments on the April 2012 UNC License Amendment
Request for Revised Groundwater Protection Standards Based on Updated Background
Concentrations.
June 2013
NRC issues Request for Additional Information (RAI) pertaining to License Amendment
Request (April 2012) for Revised Groundwater Protection Standards.
June 2013
Fourth Five Year Review completed.
September 2013
NNEPA formally requests that UNC locate, permit, drill, construct and operate sentinel
wells on north of the UNC Church Rock Mill Site Section 36 boundary.
October 2013
UNC submits to NRC a response to the RAI pertaining to License Amendment Request
(April 2012) for Revised Groundwater Protection Standards.
January 2014
UNC submits to NRC a revised groundwater flow model report.
June 2014
NRC issued a draft Environmental Assessment (EA) pertaining to the License Amendment
Request (April 2012) for Revised Groundwater Protection Standards for review by other
governmental agencies.
August 2014
UNC submits proposed sentinel well locations north of the UNC Church Rock Mill Site
Section 36 boundary.
September 2014
EPA and NMED issue comments to NRC regarding August 2014 EA pertaining to the
License Amendment Request (April 2012) for Revised Groundwater Protection.
October 2014
UNC submits proposed potential cleanup levels to EPA: "Updated Overview of Draft
Attached Tables, Summary Comparisons of Upper Prediction Limits for Parameter
Concentrations in Background Groundwater to Site Cleanup Standards and Potential
ARARs for All Three Hydrostratigraphic.Units at the Church Rock Mill Tailings Site (March
29, 2015)."
March 2015
NRC issues License Amendment No. 52 on April 9, 2015 which approves the April 2012
license amendment request related to revised groundwater protection standards (based
on updated statistically calculated background threshold values). The three site
hydrostratigraphic units are addressed individually.
April 2015
EPA indicates that UNC may proceed with the SWSFS using the March 2015 proposed
potential cleanup levels.
September 2015
GE submits to NRC a license amendment request (October 22, 2015) to update the license
for progress and changes that have taken place with respect to corrective action program
and the on-going re-design and environmental review of the tailings disposal
impoundment to incorporate mine spoil. Some editorial and typographical corrections are
also proposed (including corrections to License standards).This license amendment
request was intended to withdraw and replace a previous request dated January 22, 2015.
October 2015
UNC submits to EPA a letter describing how the proposed monitoring well network on the
Navajo Reservation will be used to collect the hydrogeochemical information needed to
establish areas where future administrative controls would be applied, in support of a
future remedy.
April 2016
UNC Church Rock Uranium Mill Superfund Site
September 2018 .
Fifth Five-Year Review
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Chronology of Events for UNC and NECR Sites
Event
Date
EPA and the Navajo Nation approve the proposed monitoring well locations on the Navajo
Reservation and agree that UNC that should proceed with the plan to permit and install
monitoring wells north of the Section 36 boundary on the Navajo Reservation (email from
Janet Brooks to Roy Blickwedel, July 27, 2016).
July 2016
EPA requests quarterly reporting of northern Zone 3 monitoring well sampling, starting
with October 2016 monitoring event.
August 2016
GE/UNC requests (December 8, 2016, corrected February 13, 2017) to amend previous
license amendment request that was submitted on October 22, 2015. The amendment is
to remove well GW 2 as a POC well for the Southwest Alluvium. All other aspects of the
October 22, 2015 request remain the same.
February 2017
UNC submits to the Navajo Nation Department of Water Resources (Technical,
Construction and Operations Branch [TCOB]), a preliminary well drilling permit application
April 2017
UNC Church Rock Uranium'Mill Superfund Site
September 2018
Fifth Five-Year Review
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APPENDIX C
INTERVIEW RECORDS
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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INTERVIEW RECORD
Site Name: UNC-Church Rock Superfund Site
EPA ID#: NMD030443303
Subject: Fifth Five-Year Review
Time:
.2:00
Date:
11/1/2017
Type: Visit
Location of Visit:
Coyote Canyon Chapter House
Contact Made By:
Name: Ms. Janet Brooks
Title:
Remedial Project Manager
Organization:
EPA Region 6
Name: Mr. Angelo Ortelli
Mr. Steve Jetter
Title: Project Manager
Project Manager
Organization: NMED
Individual Contacted:
Name: Mr. /Ms. Sharon Warren
Also, Mr. Leroy and Ms. Thelma Beyal,
residents near Mill (Hardground Flats)
Title: Chapter Secretary
Organization:
Coyote Canyon Chapter
Telephone No:
Fax No:
E-Mail Address:
Street Address:
Summary Of Conversation
Question 1: What is your overall impression of the project? (general sentiment)
No opinion - Ms. Warren is not well informed about the project. She would really appreciate getting more
information and a site tour for the Chapter Council, interested community members, and herself.
Question 2: What effects have the site operations had on the surrounding community?
There has been an issue with work associated with mine site activities and detouring of traffic during
bridge construction. People locking access gates and preventing access to communities (Hardground Flats)
further up road. This is an issue for emergency response.
Question 3: Are you aware of any community concerns regarding the site or its operation and
UNC Church Rock Uranium Mill Superfund Site Fifth Five-Year Review
September 2018
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administration? If so, please give details.
Community is worried about wind born dust contamination and has a study of this been performed. Janet
explained that this was done at least locally in 1995. Based on the time since it was done, there was
concern that additional study should be performed.
Community concerned that in-depth health study has not been performed. How many people have been
impacted - health wise from the uranium mining and mill activities?
Leroy Beyal had concern with what effects on livestock and deer eating contaminated food and how these
effects human consumption of the meat.
Question 4: Are you aware of any complaints, incidents or activities at the Site such as vandalism,
trespassing, or emergency response from local authorities? If so, please provide details.
No, none during this five-year period. Heard of issues with down fences and cattle trespasses from Red
Pond Road community but these occurred over five years ago.
Question 5: Do you feel well informed about the Site's activities and progress?
No - Coyote Canyon Chapter has not been kept informed on the UNC Mill Site remediation. We were
informed that Coyote Canyon is in the Fort Defiance Agency and not the Crownpoint/Eastern Agency which
includes the Pinedale and Church Rock Chapters which are closer to the Site.
Question 6: Do you have any comments, questions, or recommendations regarding the Site's
management or operation?
Ms. Warren recommended that there be more community involvement and updates with the Coyote
Canyon Chapter. This could take the form of fact sheet, meetings or simply email updates. At least semi-
annual meetings/updates should be considered. It is best to advertise on local Gallup radio channel (???)
in both English and Navajo.
Leroy Beyal recommended that presentation be visual in nature, show numbers, trends, satellite imagery,
etc.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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INTERVIEW RECORD
Site Name: UNC-Church Rock Superfund Site
EPA ID #: NMD030443303
Subject: Fifth Five-Year Review
Time:
9:40
Date:
11/2/2017
Type: Visit
Location of Visit:
Pinedale Chapter House
Contact Made By:
Name: Ms. Janet Brooks
Title:
Organization:
Remedial Project Manager
EPA Region 6
Name: Mr. Angelo Ortelli
Title:
Organization:
Steve Jetter
Project Managers
NMED
Individual Contacted:.
Name:
Title:
Organization: Member of
Ms. Joann Miller (Citizen 1)
Ms. Gladys Brody (Citizen 2)
Community Land Use Planning
Committee
Telephone No:
Street Address:
Fax No:
E-Mail Address:
Summary of Conversation
Question 1: What is your overall impression of the project? (general sentiment)
Both women are not familiar with what is going on at the site. They were glad to hear that the mine site
will be cleaned up and returned to productive use.
Question 2: What effects have the site operations had on the surrounding community?
People are still concerned with effects of mine discharge water had on animals that drank the water and
for people that consumed these animals
UNC Church Rock Uranium Mill Superfund Site Fifth Five-Year Review
September 2018
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Question 3: Are you aware of any community concerns regarding the site or its operation and
administration? If so, please give details.
There was concern expressed about livelihood of area residents. This included concern about downwinders
(effects on people living downwind from the mine and tailing disposal area) and concern with windblown
contamination. Concern was also expressed regarding people gathering wood from the area that is used
as firewood to heat homes. How they might be affected.
There was also concern for when large flood events occur in the arroyo that passes by the site and the
potential to release contamination or damage the repository.
Question 4: Are you aware of any complaints, incidents or activities at the Site such as vandalism,
trespassing, or emergency response from local authorities? If so, please provide details.
Neither women were aware of any incidents occurring at the site.
Question 5: Do you feel well informed about the Site's activities and progress?
No - Both women said they were not well informed about the-site activities or progress.
Question 6: Do you have any comments, questions, or recommendations regarding the Site's
management or operation?
Both women thought the should be more outreach and education about the site. Thought it would be
beneficial to educate the youth by providing educational material or outreach to area boarding schools.
They asked about how long is the long-term monitoring going to take place.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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INTERVIEW RECORD
Site Name: United Nuclear Corporation (UNC) Church
Rock Superfund Site
EPA ID No.: NMD030443303
Subject: Fifth Five Year Review
Time: Date:
Type: email solicitation
Location of Visit:
Contact Made By:
Name: Janet Brooks
Title: Remedial Project
Manager
Organization: EPA Region 6
Name: Steve Jetter
Title: Project Manager
Organization: NMED
Individual Contacted:
Name: Art Kleinrath
Title:
Organization: Department of Energy,
Office of Legacy Management
Telephone No: 970-248-6034
Fax No:
E-Mail Address: art.kleinrath@LM.doe.gov
Street Address: 2597 Legacy Way
City, State, Zip: Grand Junction, CO 81503
Summary Of Conversation
Question 1 - What is the U.S. Department of Energy's (DOE's) role on this project?
The Department of Energy (DOE) has no formal role in the CERCLA process. It does perform all the work
under UMTRCA. That process including the O&M if any facility whether it be an active water remediation
or a facility for the disposal of mine waste is solely between USEPA and its responsible party.
Question 2 - What is your overall impression of the groundwater remediation effort at the site?
Southwest alluvium has only S04, manganese, chloride, nickel at all exceeding and none are very much over
the limits. The ground water that was polluted was not natural ground water. Primarily, the ground water
that was polluted was the manmade ground water that was pumped from the mines and which then
drained into the Southwest Alluvium and into the Zone 1 and into the Zone 3.
According to the US EPA website: "Four water wells are within a 4-mile radius, the nearest being 1.7 miles
northeast of the Site; however, nearby residents generally have used bottled water." (from site profile). It
would appear risk is mitigated.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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Question 3 - From your perspective, what effects have site operations had on the surrounding
community?
The NRC regulated clean-up caused awareness and maintained the apprehension of potential
contamination. The EPA activities have maintained that awareness. The EPA activities have provided much
more understanding and education to the public on the issue.
Question 4 - Are you aware of any community concerns regarding the site or its operation and
administration? If so, please provide details.
In regards to the Ground water only a general "is it safe?" concern. I also get a lot of feeling of "can we just
get it done".
Question 5 - Have there been routine communications or activities (e.g., site visits, inspections, reporting
activities, etc.) conducted by your office regarding the site? If so, please describe purpose and results.
Review and comment on documents: The DOE purpose in the review process is twofold, first to ensure the
intended end-state does not conflict with DOE future obligations under UMTRCA. Second is DOE-LM has
many years of experience with cells such as the UMTRCA cell and can provide useful history, expertise and
experience.
Question 6 - Is the ground-water remedy progressing in accordance with DOE's expectations or
requirements for the site? Please explain.
DOE expects the groundwater remedy to be completed and require no more monitoring at the time of NRC
termination of license and transfer to DOE.
Question 7 - Is the DOE aware of opportunities to optimize the operation, maintenance, or sampling efforts
UNC Church Rock Uranium Mill Superfund Site Fifth Five-Year Review
September 2018
-------
at the site?
DOE expects the groundwater remedy to be completed and require no monitoring under UMTRCA at the
time of NRC termination of license and transfer to DOE.
Question 8 - From DOE's perspective, have any of the changes in site operations had an effect on the.
protectiveness or effectiveness of the ground-water remedy? Please explain.
We do not know of any such changes. The Groundwater remedy is nearing its end of effectiveness.
Question 9 - Are you aware of any changes in DOE standards since the time the remedial.approach was
delineated which may call into question the protectiveness or effectiveness of the remedial approach?
The numerical standards for media (soil/water/flux) established by the NRC are and will be set by license '
amendment. All such standards are risk based and protective. DOE will set, subject to NRC concurrence,
operational parameters
Question 10 - Do you feel well informed about the site's activities and progress?
Yes we are kept informed.
Question 11 - Do you have and comments, suggestions, or recommendations regarding the site's
management or operation?
We do not have any additional input, because we are included in the development of the site.plans.so our
comments are made during that time.
UNG Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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INTERVIEW RECORD
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UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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Interview Faim
Paae3
in Ote SouSlwsest Alluvial system, active pumping was discontinued ti 2DD1 wfih EPA and NRC
approve ?o conduct an 1 B-monyi natural aftenuatlB?] 5esL The repwt, compteted in Decembe?
2C32, recommended the replacement of me current remedy with a natural attenuation remedy
for metals and radlonucldes, and a Technical impraeacaiiliny Waive? for si&fele and TDS. Tits
Soutfivsrest Alliwium compile® wfth af vfi tfie NRC groundwater proCECilon saandaids, and the
EPA E&ndafftfs fw an hazardous eonstSrerfiEv
Zane3pumpCng was dtecontkiLred &iO«cernber2MO with the approvalaTNRC. EPA
necogntzwl durfing me 1st Five-Year RevtEW otf 1398 Biat Zone 3 pumping was noQ effective, and
was pertiaps decrfmen&S to tfie con&nment of seepage-Impacted water In Zone 3. Approval to
cease pumping was granted in December 20DO, conditioned on the hstaflatton era sentinel
mortfiwlng well and the evaluation oJ obis' remedy Enhancement ailemash-es. Alternate
remedy enhancements were plot tested between 2flD3 and 2D12. None Have been Eucce&sai
in ertfiancfng me effecff/en&Es of She remedy sw veay fan®. However. ifie hydraulic iSactailing
test resisted in the'placement sf sane new extraction we Is thai avoid she problems assocte-Ed
wlBi iftefMiner purapfrig system. Pumpeig fiom Bie nEW Ztme 3 weBS contauee.
SenfcneJ weas "or zone 3 have been proposed for placement on Bie Navajo Reservation, and
are afirentfy In the permitting process. The weds wHt a1 so be used to conftm the groundwater
flow model
QuasiieiJ - Dili3ha Bronaimtsrranisdj-aiiKtemas expected raia ScnfimvrAILavinaiandZcaa S?
Hctv wall did the groradsrEtsr moody pssfene?
Ttie groundwater pumping remedy has achieved skpifflcant desalination or the Impaled
grounfflrater in each area. As annotated in the June 159S Recad of Oecfsion (ROD} ana the
inHst Ff«'e-fea? Re-.tew, and as substantiated (n the varfcus te<3inlca£ reports for ffle site,
groundwater pumping has reaped the Emits or its eJTecCven&ss. in as three groundwater target
areas ilstfier groundwater pump&ig will haw no additional, appredaKe, benettctal eiTect m
achieving cleanup goa& beyond tits natural processes thas are accurrttg. The remedy Has
ftmcfioned as well as was expected wfien EPA chose Lt In the RO£>_
As a praeUcat mailer, EPA expec-ed sftat H wotfd be necessary to reevaluate the performance
goalsaHtwereestabESiedmtheROD. EPA expect uiat significant desaasationi or the
Impacted media could occur and tfial It would be necessary to change the performance goals
that were estaKished fn site iROD. Despae =ns anticipated tecJintfogjca! [imitations,
grauntfv/ater quality In llse olfsfte portion of zone 11s in compliance vstth ate NRC
-------
Tntprmgw FqEHL
Pap 3
T8ie remedy ftincboned as wei as was expected amen EPA chose R m the Jiuie 1536 Record or
Decision {ROD). Wlifle the groundwater pumping remedy has not attained aft of the rem escort
goals got were establssiec irv the Record off Decision (ROD), ttis was anKSpatea tn ma ROD.
EPA expKSed aiat sigiifffiGanf? desatisation: of the impacted mesea could occur anififtat li woitfd
be necessary to change ttie performance goals thai were efia&llshsd in the ROO.
UNC lias expended fremertdOK effort ants resources to enhance fits effectiveness or EPA's
selected renietfy Tor Zone 3 as ffecorrenentfed in (he 2nd Five-Year Review. While UNCs
efforts nave Improved upon the oftgftal remedial design, they too are reacsurtg ate Built ortrreff
eTfeoUreness. Migration of the zone 3 pnene has been slowed, tout fi lalii oniy cease !d morale
when certain natural ftyiEauac ranees arc balanced by the chemical reactions that are
attenuating and restricting the fnovemen? of tfte seepage-Impaled water. A3 Oils point
continued tfawngratfent migration can no longer be altered by i&ng hyiQaiiBc modifications [Le.
pumping^ due to the d$ of the geotogte strata watiin wtiKSi 5he groundwater moves. UNC has .
nod Identflled other proven. innovative, cs emerging technologies that urn achieve dsanup goals
in Zone 3 Because or declining saturated thicknesses, 'Jie alteration or arto&ic sant£s&ne to
day, encrustation;; and the resuaant poiw Steniatlon yl&ds.
PisTifilng from Zc?ie 3 wells conteiues, albeit H at a consistently decking ylea. Groundwater
recovery from an Zone 3 psumpfngwels comKned was a&oiti 2.3 gaOons per minute for about
the same as a gasden hose tuned on row) at Site Sfne or the last Five-year Review. it is how
about 1.4 gpm. The pro portion or seepage-tmpaxsed water Feay.eretf to bacfcrpoiBid water
recovered! fe steafflty sliHllng towards the latter. The groundwater recovery Is rapidly meeting Ots
limits or any beneficial etreei IT fi has not affleady reacted that pout.
Qnasaca 5 - Whii dcsi ths mcaitciiaE data shear? Doing operation End povt cpastiea of tha ntmfrdial
iyrtaiEi, Trfire &ejb tumdj Antral centamimzit LstbLi docnjiiiac otst tica?
Descriptions of contaminant trends def>end on the compound consiaerea ana wttether one is
discussing Zone 1. Z)one 3, or the Soiritwresl Muvlisit, and so the annual rewfew re parte should
be consulted for detailed answers to ircs question, m general, the bends aw hazardous
consUtuervts had diminished both with distance from the laltngs disposal area and through ®ne
and readied asymptotic contstions &e?&ns grounawater recovery ceased in Zone 1 and the
Southwest Alluvium. The concentrations stice pumping was terminated remain stattfe, and are
the rss&l oT the naSinai capacfiy oT tna formation id fcnmobli&a the Jiazardois constituents
rather than the former pumping thai tocft place.
(ft Zone 3, concentrations o7 regula-ed canEtmientB have been stable Star severs! years.
ConcEfi&atlonB at regu&tsd constituent may vary tn response to variations m the pimping
corfflgurattei which Is routinely modeled to promote ate recovery ol seepage-impacted
groum&sater and mtatrnts ttie recovery or background gioiinffisater. As reported a&ove, tlte .
proportion or non-tmpaeied groundwater recovery to seepage-Impacted groundwater recovery is
unavoidably Increasing as the saturated thickness de<£nes. Tte limited giou?i floater recovery
that ifflC is currently able to accomplish is sidTlclent to capage seepage-impactedi water at the
UNC Church Rock Uranium Mill Superfund Site
September 2018-
Fifth Five-Year Review
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lEterviewForai
PaEB3
leading edgs of fenpacts, bid Is not and wll not ever be capatee of aailevlng elthef a&e cisreflt
NRC groiHiitoatES- pnfisction standads or trie CPA's ROD standards aasent die cxsnptets
dEwatering of zone 3 which is tecJinoa>g!raiiy impracaicaBie.
Some of the EPA-fnandateffl otKisiKuantE-of-concem, sudi 3S siSfats and ntanganEse. are
MntnffleiS solely by equSJbration wfth naturally occurring rntiera& m tlie ftsrciatlon tfcat the watB?
moves cirwigft. As a consequence, tte monttoetng eata S&r aieEe cohsa&rents are iremaiftabty
stable throaig?) ante. R was WRCs conclusfon In t953 that these con&t&Knte are inappropriate
for detEimfnlng Bie eflectiweness of the groundwater corrective acton program.
QlUSdCfi 6 " FlC3 yCfl? penpSCtivSk, lui^S soy flf liu im^U'g.'tg SBnudl&l nre.,FMSflftsp[aizL
First, let me explain tfie Genejal Etacffic Company's (GE's) role on this project. to September
1S97 UNC was acquired by a company that was Itt turn acqu&ed by GE, and as a result UNC
bEcazne a whoGy-oumed, [indirect su&Sdlajy of GE. GE Corporate Environmental Programs was
retailed thraugji a separate aam&iistrative services agreement to assist UNC baft tE<2inicatty
and administratively waai environments* issues at Cfisirch Rocfc.
As tsGE's pejspecflve, a is certain thai die current remedy Has reached the Ifnlts of
effectiveness ror Zone i and the Southwest Alluvium. Miaecvefr, the remedial systems have
achieves what was anticipated In the ROD. Water palRy due & taiBigs seiepage has generally
remained statrte or fcnproved since tlis ce&safian of pisrcplng cperadons In both iftase unBs.
UNC bsnevas bsat t!ia termination of groundwater coitkOvb acaona in Zom 1 and tits
Southwest Altuy&nn Is Dong ovardua.
En Zona 3. the new pisnping configuration wfticai was adopted efnce Ore last ave-year review
has slowed the rate at atiteh seepage-impacted water can migrate. This has been beneftc&l
because it allowed natural restoraave processes to &e more effective. Over. Bie past few years.
UNC lias adju£Ed the oorfflgiffatlDn by addftg welfe and rcmotfng tsisr. as needed to maximize
hyi&auEc control over Bie seepage-impacted water. UNC also fcijecteffi ailattnaylntD the
seepage stool to h£p neutralize the seepage-flmpactetf watec however, it tos necessary to
cease the aifcallnSy inaction because of Els tendency to promote tfce retention of isantam in
solution. Currant groundwater recovery from all Zone 3 pumping wefls combined fe aaout 1.4
gaflorts per minute, and this tats te in steady iSedtne. It win be necessary to cJtanga the
remadiaJ goals andtar to tnvofce other administrative eontroEa. supported by esntine] waa
monitoring, for the CERCLA process to attain closure and ton the site to be transferred to
the DOE lor Bong-term stewardship.
QnaBjai ? - Are there any trend-; that shew cantasninani lavah ianBaiiag er ihat sdicgtB contsmsd
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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loterpiew Fomi
Pap 3
mrptrvrtnn ivFt^Ka rrr/nn/t-rrTihir pf—tip in ifha throe. aq^aftg arras? Plflaift CipLsill
There are no water quality SreidE, which are aCrQutaKe to the seepage or tailing s-lmpatSKl
water, io tidtea^ thafl coniaMnaiii levels are increasing in anyoTitie remedial target areas
(none of which may be considered aquifers). Vaiotlons In contaminant wmcentraaons are
afivays expiatned by naiurai processes thai are uiwelaiEd So talEngs-seepage. SEnce me 1st
Rve-Yeai Review, the areas oT impastf have teen staKs to declining in. esSenL
tn the last Flv&-Y&ar R&vlew. we reconunendBd that torts queattoa be revised to be mora
mBantaghd; howsvsr, that suggestion seams to liave been dismissed Tlia qu&stlon thai
should be asked now and in the future la not whetltBr contaminant levefa increased or
decreased. mil ratnsr, whether the changes are attributable to tailings saepage; and
second whether those changes an within the range of concentrations that axe naturally
en count arsd Iri tits background watar. Tlraes two qfUiBstlane are Jar mora meaningful as a
basis for tfaelslon-making, and the answers to there indicate that the remedy la
protective and should terniinsted.
Quavica S - Frnin GE's psrspsctva, ini* any of -is cimcs; in. liw ojsratioaj had an of&ct an tiis
proisetivsnais ci aQsctrveasu oftLa prcioil-iintsff ramflip? Pfaass «xplain.
The cessation of paimping has noi affected pratectfoeness. The ramefflation remans protective
of human heaflh and the environment The remedy functioned asssll as was expected when
EPA chose It in the June I9BB Record of Decisis?) {HOD). EPA expected thai significant
desa&satlofi or the impacted meffia wuifid limit or end Hie abffiy to achieve ErcprcvKTreni in
grounffisater quality yuoisgji continued pumping, and thai It would be necessary to change the
pertorniance goafs thai were established In the ROD.
GE bsDevss that it fs the aiteruisave capacity of the naSisal sy£Em. mora than me pumping
remedy, which has pnxtused most ol the remedial progress that has aee?i observed m the
Southwest Alluvium and &i Zone 1. The sSaaie wa3e? cftsmlstey thai has occurred pcst-
shutdown aP.e®5s to lite coiwausloit.
As for zone 3, UNC remains wining io recover seepaipe-lmpac-Ed groun^-A-ater unffi n fc no
longer practicable 'o ffioso, and to asSsl EPA to e&iaaiteh off-site admEilstratlve oorrtrote. The
pending fn&tallatton of sentlnei wells in Zone 3 Is part?y to support the aflMnlstratfre cortircte.
The demitton oJ "practfcabfe" should be based upon an sautiy id susta&abry pump seepage-
Impac-Ed water In sufReSent qusjrtltSes -a mHgate seepagE-rrigraHon. it appears that ?fts
recovery system ts very close to, or at, this limit The ejidpolnl cannot be based upon the .
Hinent ROD slandaids; those levels quite slmpiy can never be achieved.
Qassliaa 9 - Frees vrnuparrpecfeva, •siiit affect; krm jita 0parz.icn.1h2d aa the '.imuamrffng ctiiimiiiiiMv?
Reiaaore latth She smrpunfling community lave bEen productive and posittve.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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TntPTvipw Form
PsebJ
QuaiticnJO - Ar#},vuznra»ofanycBEamG3ity ccsceniaraBaiding 'din titacrib^Hsatifflianit
adimnktRoica? If so, ploasa proviSs dotaDs.
UNC fs nsfl aware or any community concerns regarffirtg site operations.
Qiw^ticii 31 - Kava thar« wen any ccziqilafzirs, vktlatkxiu, ar cthar incidsBft; raliSd1c "is siia That rsqnira
a rapcou. by yanr c&£4? I? so, pLoass dascnba tbfl svanb an/3 isralts of tfaa i-cipansai. .
None.
Qnradca 12 - Da yea havs aad comEsnti!, ssgBBStiaiu, or iscocassaditscai: rsfiitLina t2» prcj&c!?
EPA recognized as earty as Hie 1S36 ROD and as fate as ate FTret 5-year Review ft 1953, maa
technical Qnnltatfons would be reached wasi reEpecd to meeting She goals thai were established
for ate site. in the Fires 5-year revfew tn 1 &9S, EPA validated ma technical Enttaaans mat Q
anticipated In the ROD rnaie side mat lite s-axetfiolders are asytivolvefl. However, ttie
supplemental FS vim nol cihange what EPA antedated 25 yeare ago tn Qie ROD. As staled In
Appendix A or the HOD: 'However, opsrstional results may demonstrate tfia! it Is
tecftidcsray lnu>racttc& Co aefaleve aD elearcup Esvete in a raasonaatie' time period, and a
waiver to meeting esftatn contaminant
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iEteniewFomi
Pan? 3
cfesfiup goals cannot fcs met, asid tsial waW&s and otm® sdnflnSSraEve Soots am Biare to be
adopted Before the Cfwjrch Rock Mill can be transferred so the Depadm^it & Energfs Long-
term Stewasi&h^ Pnqr^
UNC understands maa USEPA may evsiusle institutional earn rate as a potentfas supplement tp
me ROD, Ki affldlBore to or Hi axn&lnallan wltsi Hie adaption cr xratura] aflemjataKi mechanisms.
Technical JmpractleaKBty Waivers or rnoffiTted cleanup standards for the Cfcjrch Rock S3e. As
EPA Ie aaare,, UNC vrartas wtm the NavaJlo Nation Tram 20D1 to 2 BO 3 to devE&p a?i [nstSSiriliHTsf
comtrDS pan tb prevent jpcGESitlal exposure to seepage-impaled water. MeSfter me proposed
Trt&af Re&oliEthwi nog- the eznrtrasimerc&i slgn/Hif-way mat was aerelopeiS ftas (sen ftumany
responded to gfice Biey were first proposed mcoe tsian HQ years ago. Gften mat B is uraeaisaJc
to consider Itis background grMintf«ster as a v&Ke source &? water for Haitian asidibr asilmal
Gonsumptfon at present pr In tsie ftrtairfe, UNC continues So believe admlnfeira&va controfe should
be considered as ps3 off me IBnal remetify. Ra- Lis past UNC Itas demKisdateS its wflllngne&s
ovEff the past 20 years so word cooperative^ wtth all partes ?o ibrge an outcome mat Benefits
lowf resfiJents. Ttt& las Lnelufied an offles1 made moae than 15 years ago Id provide tor asi ,
alternative water soim?e to neaay residents shoultf they not lave access So viable supplies
either stock watering or domestic consumption because of the naturally poo? water quaOty In
me region.
Ttianfcyou 'orafloafng us so sharemi'r perspective during mis Sffih Syeasrseiview.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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APPENDIX D
DOCUMENTS REVIEWED
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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Documents Reviewed
Chester Engineers, 2009. Revised Submittal: Site-Wide Supplemental Feasibility Study Part II, United Nuclear
Corporation, Church Rock Tailings Site, Church Rock, New Mexico. July 2009.
Chester Engineers, 2011b, Revised Site-Wide Supplemental Feasibility Study Parts I and II, Church Rock
Site, Church Rock, New Mexico. April 26, 2011.
Chester Engineers, 2012. Updated Baseline Human Health Risk Assessment-Final, Church Rock Site, Church
Rock, New Mexico. August 2012.
Chester Engineers, 2014. Annual Review Report-2013, Groundwater Corrective Action, Church Rock
Site, Church Rock, New Mexico. January 2014.
Chester Engineers, 2014. Groundwater Flow Model of the Church Rock Site and Local Area, Church Rock,
New Mexico - Revised. June 2014.
Chester Engineers, 2015. AnnualReview Report-2014, Groundwater Corrective Action, Church Rock
Site, Church Rock, New Mexico. January 2015.
Chester Engineers, l2015. Email from Robert Warren (Chester Engineers) to Janet Brooks (EPA-RPM),
Subjert: Updated UPL95 summary tables. Attached Tables and Summary Comparisons of Upper
Prediction Limits for Parameter Concentrations in Background Groundwater to Site Cleanup Standards
and Potential ARARs for All Three Hydrostratigraphic Units at the UNC Church Rock Mill Tailings Site.
March 29, 2015.
Chester Engineers, 2016. Annual Review Report-2015, Groundwater Corrective Action, Church Rock
Site, Church Rock, New Mexico. February 2016.
Chester Engineers, 2017a. Working Draft Revised Site-Wide Supplemental Feasibility Study Part III, United
Nuclear Corporation, Church Rock Tailings Site, Church Rock, New Mexico. January 2017.
Chester Engineers, 2017b. Annual Review Report-2016, Groundwater Corrective Action, Church Rock
Site, Church Rock, New Mexico. February 2017.
General Electric Company (by Roy S. Blickwedel), 2006. Regulatory Significance of the Occurrence and
Distribution of Dissolved Uranium in Groundwaters of the Southwest Alluvium, Church Rock Site, New
Mexico. ADAMS Accession Number ML061000082. March 2006.
General Electric Company, 2012, Letter to NRC, Subject: License Amendment Request for Revised
Groundwater Protection Standards based on Updated Background Concentrations, Source Materials
License SUA-1475, Groundwater Corrective Action Program, United Nuclear Corporation Church Rock
Mill and Tailings Site. April 17, 2012.
Hatch-Chester, 2018. Annual Review Report-2017, Groundwater Corrective Action, Church Rock Site,
UIMC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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Church Rock, New Mexico. January 2018.
New Mexico Environment Department, 2014. Letter from Jerry Schoeppner, Chief (Ground Water Quality
Bureau) to Thomas McLaughlin, Project Manager (U.S. Nuclear Regulatory Commission). Response to 8/15/2014
Nuclear Regulatory Commission (NRC) Draft Environmental Assessment (EA) for the Proposed Amendment
Request for United Nuclear Corporation (UNC), Church Rock Mill Site, Source Materials License SUA-1475.
October 28, 2014.
U.S. Environmental Protection Agency (EPA), 1988. Record of Decision, United Nuclear Corporation,
Ground Water Operable Unit, McKinley County, New Mexico. EPA R06-R88-44, Region 6. September
1988. .
U.S. EPA, 2001. Comprehensive Five-Year Review Guidance, Office of Solid Waste and Emergency
Response, EPA 540-R-01-007, OSWER No. 9355.7-03B-P. June 2001.
U.S. EPA, 2013. Fourth Five-Year Review Report for the United Nuclear Corporation Ground Water
Operable Unit, Church Rock, McKinley County, New Mexico, September 2013.
U.S. EPA, 2013. Memorandum (13-R06-001): Comments on background ground water conditions in the
Southwest Alluvium and Zones 1 and 3 of the Upper Gallup Sandstone at the United Nuclear Corporation Church
Rock Mill and Tailings Site, Church Rock, New Mexico. National Risk Management Research Laboratory,
Ground Water and Ecosystems Restoration Division, Office of Research and Development (ORD).
From Ralph Ludwig and Robert Ford to Janet Brooks. March 25, 2013.
U.S. EPA, 2013. Record of Decision, United Nuclear Corporation, McKinley County, New Mexico. EPA
ID: NMD030443303, Operable Unit: OU02, Surface Soil Operable Unit. EPA Region 6, Document No.
681353. March 29, 2013.
U.S. EPA, 2016a. Transmittal of the Five-Year Recommended Template, Office of Superfund Remediation and
Technology Innovation. OSWER, OLEM-9200.0-89. January 20, 2016. Updated October 11, 2016.
U.S. EPA, 2016b. Letter from Alexis Strauss, Acting Regional Administrator, EPA Region 9 to The Honorable
Russell Begeye, President, Navajo Nation Abandoned Uranium Mines on the Navajo Nation. July 18, 2016.
U.S. Nuclear Regulatory Commission, 2015. Letterfrom Andrew Persinko, Deputy Director (NRC, Division of
Decommissioning, Uranium Recovery, and Waste Programs) to Roy Blickwedel (General Electric Company).
License Amendment Request for Revised Groundwater Protection Standards Based on Updated Background
Concentrations, Source Materials License SUA-1475, Groundwater Corrective Action Program, United
Nuclear Corporation Church Rock Mill and Tailings Site. License Number SUA-1475, Amendment No. 52.
April 9, 2015.
Weimer, W.C., R.R. Kinnison, J.H. Reeves, 1981. Survey of Radionuclide Distributions Resulting from the Church
Rock, New Mexico, Uranium Mill Tailings Pond Dam Failure. Prepared by the Pacific Northwest Laboratory for
Division of Waste Management, Office of Nuclear Material Safety and Safeguards, U.S. Nuclear Regulatory
Commission, Washington D.C. NUREG/CR-2449, PNL-4122. December 1981.
UNC Church Rock Uranium Mill Superfund Site
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Fifth Five-Year Review
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APPENDIX E
SITE PHOTOGRAPHS
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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Photograph 1: The gated and secured site access road to the tailings disposal cells and ground water
remedial action target areas.
Photograph 2: Southeast view across the lined evaporation ponds on the south cell. lV>nds contain mostly
supplemental water from the facility supply well, and less than 5 percent from ground water extraction.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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Photograph 3: North view across Pipeline Arroyo, shows the close proximity of Wells GW-2 (south
side) and GW-3 (north side) to the severely eroded and sloughed embankments.
Photograph 4: North view across Pipeline Arroyo, shows the close proximity of Well GW-3 (north
side) to the severely eroded and sloughed embankment, prohibiting sampling due to safety concerns.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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Photogi-aph 5: Southwest view of Pipeline Arroyo, downstream of the "Nick Point", that shows the
severely eroded and sloughed embankments.
Photograph 6: Southeast view of a bend in Pipeline Arroyo at the "Nick Point", that shows the
continual undercutting and erosion of the embankment.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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Photograph 7: North view across the northwest ground water remedial action area, that shows the
Zone 3 ground water extraction wells.
UNC Church Rock Uranium Mill Superfund Site
September 2018
Fifth Five-Year Review
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