United Nuclear Corporation Superfund Site U.S. EPA Region 6
Surface Soil Operable Unit Proposed Plan /| Superfund Program
Gallup, New Mexico Dallas, Texas
July 20, 2012
Dates to Remember
Public Comment Period:
July 20, 2012 - September 21, 2012
The EPA and NMED will accept written comments on the
Surface Soil Operable Unit Proposed Plan during the 60-day
public comment period.
Public Meeting:
The EPA will hold two public meetings to explain the Surface
Soil Operable Unit Proposed Plan. Oral and written comments
will also be accepted at the meeting.
August 29, 2012
Pinedale Chapter House
1149 Mile Marker 5
Church Rock, New Mexico 87311
Meeting Starts: 6:00 pm.
August 30, 2012
Octavia Fellin Public Library
115 West Hill Avenue
Gallup, New Mexico 87310
Meeting Starts: 6:00 pm.
The Surface Soil Operable Unit Proposed Plan is also
located on the internet at:
http://www.epa.gov/region6/6sf/newmexico/united_nuclear/nm
_united_nuclear_proposed_plan.pdf
The Administrative Record File is available for viewing at:
Octavia Fellin Public Library
115 West Hill Avenue, Gallup, NM 87310
505.863.1291
Hours: 9:00 am to 8:00 pm Monday thru Thursday
10:00 am to 6:00 pm Friday
9:00 am to 6:00pm Saturday
Navaio Nation Superfund Office
Highway 264/43 Crest road
St. Michaels, Arizona 86511
928.871.6859
U. S. Environmental Protection Agency
announces the Surface Soil Operable Unit
Proposed Plan
This Surface Soil Operable Unit (OU) Proposed
Plan identifies the Preferred Alternative for
permanent disposal of low level threat mine
waste from the Northeast Church Rock Mine
Site (NECR Site) within the Tailings Disposal
Area located on the United Nuclear Corporation
Superfund Site (UNC Site; Figures 1 and 4).
This document is issued by the U.S.
Environmental Protection Agency (EPA), the
lead agency for site activities, after review by
the New Mexico Environment Department
(NMED), the support agency for site activities.
This Surface Soil OU Proposed Plan describes
the process used to evaluate remedial
alternatives regarding disposal of the low level
threat mine waste from the NECR Site at the
UNC Site. This Surface Soil OU Proposed Plan
deals only with a limited aspect of the surface
soil OU remedy at the UNC Site—the disposal
of low level mine waste from the NECR Site
within the Tailings Disposal Area of the UNC
Site and is taken as an intermediate step prior to
final remedial action for the surface soil OU at
the UNC Site (see Scope and Role of the
Response Action for further discussion). For the
purposes of this Surface Soil OU Proposed Plan,
the term mine waste refers to NECR Site soil
that is contaminated with hazardous substances
that are either radioactive or heavy metals.
The EPA is evaluating disposal alternatives at
the UNC Site in support of the Non-Time-
Critical Removal Action Memorandum for the
NECR Site signed September 29, 2011,
(hereafter referred to as the 2011 Non-Time-
Critical Removal Action Memorandum; EPA,
201 lb). In the 2011 Non-Time-Critical Removal
Action Memorandum, EPA decided to
permanently dispose of approximately
1,000,000 cubic yards of contaminated mine
waste from the NECR Site at the UNC Site, if
two things happened: Step one: EPA issues an
appropriate decision document consistent with
the National Oil and Hazardous Substances
Pollution Contingency Plan (40 CFR Part 300)
(NCP) process, including assessment of State
and community acceptance, where EPA selects
disposal of mine waste from the NECR Site
within the Tailings Disposal Area of the UNC
Site as a surface soil OU remedy for the UNC
Site, and Step two: the U.S. Nuclear Regulatory
llll IIMill Illl II
661940
008906
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfimd Site
July 20, 2012 Page 2 of 69
Commission (NRC)
agrees to amend United
Nuclear Corporation's
license to allow this
disposal.
This Surface Soil OU
Proposed Plan is part of
the NCP process (Figure
2) that will lead to EPA's
selection of the remedy
for the surface soil OU at
the UNC Site with respect
to the disposal of the low
level threat mine waste
from the NECR Site at the
UNC Site. The remedy
will be selected in
accordance with the NCP;
therefore, EPA will select
an alternative only after
consideration of the
public's comments. This
Surface Soil OU Proposed
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Figure 1: Northeast Church Rock Mine and United Nuclear Corporation site map
Figure 2: The Superfund Process
Site
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Community Involvement Activities Occur Throughout the Superfund Process
Enforcement Activities Occur Throughout the Superfund Process
008907
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Plan begins EPA's process to fulfill step one as
outlined in the 2011 Non-Time-Critical
Removal Action Memorandum (see previous
paragraph).
The NECR Site Consolidation Areas (Figure 3)
and the UNC Site Tailings Disposal Area
(Figure 4) will be treated as one for the purpose
of remediation. Section 104(d)(4) of the
Comprehensive Environmental Response,
Compensation, and Liability Act (CERC'LA),
42 U.S.C. § 9604(d)(4), allows EPA broad
discretion to treat noncontiguous facilities' as
one site for the purpose of taking response
actions. The only limitations prescribed by the
statute are that the facilities be reasonably
related "on the basis of geography" or "on the
basis of the threat, or potential threat to the
public health or welfare or the environment."
Once the decision is made to treat two or more
facilities as one site, wastes from the several
facilities could be managed in a coordinated
fashion at one of the facilities and still be an
"on-site" action, within the permit waiver of
CERCLA section 121(e)(1), 42 U.S.C. §
9621(e)(1) [See 55 Fed. Reg. 8666, 8690
(March 8, 1990)]. Because of the similarity of
threat posed by the mine waste in the areas on
the NECR Site where mine waste has been
deposited and consolidated (Consolidation
Areas) and the threat posed by the tailings in the
covered pits and landfills that make up the UNC
Site Tailings Disposal Area, and because of the
relative proximity of these facilities (less than 1
mile; Figure 1), EPA proposes to use its
authority under CERCLA Section 104(d)(4) to
temporarily combine the NECR Site
Consolidation Areas and the UNC Site Tailings
1 Under CERCLA, the term "facility" means (A) any building,
structure, installation, equipment, pipe or pipeline (including any
pipe into a sewer or publicly owned treatment works), well, pit,
pond, lagoon, impoundment, ditch, landfill, storage container,
motor vehicle, rolling stock, or aircraft, or
(B) any site or area where a hazardous substance has been
deposited, stored, disposed of, or placed, or otherwise come to
be located; but does not include any consumer product in
consumer use or any vessel.
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 3 of 69
Disposal Area. The combination of these two
areas, the NECR Site Consolidation Areas and
the UNC Site Tailings Disposal Area, is
temporary and for mine waste disposal purposes
only, because once all the mine waste from the
NECR Site Consolidation Areas has been
transferred to the UNC Site Tailings Disposal
Area, these facilities (i.e., the Consolidation
Areas and the Tailings Disposal Area) will no
longer be combined within the meaning of
Section 104(d)(4). Also, at no time will any of
the NECR Site, including the Consolidation
Areas be part of the UNC Site for National
Priorities List (NPL) purposes.2
This temporary combination of the two facilities
will facilitate the implementation of the
Preferred Alternative for the surface soil OU
remedial action at the UNC Site described in
this Surface Soil OU Proposed Plan, and it will
facilitate implementation of the selected
removal action for the NECR Site identified in
the 2011 Non-Time-Critical Removal Action
Memorandum (EPA, 2011b). By combining the
2 The NPL is "primarily ... an informational and management
tool . . . the listing process itself is not intended to define or
reflect the boundaries of. . . facilities or releases." 54 Fed. Reg.
41017-18 (1989)
| Arroyo * 1
Figure 3: NECR
Site
Ponds 1&2
NECR-2
008908
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Consolidation Areas and the Tailings Disposal
Area, the Preferred Alternative can be
implemented without State, Federal or local
permits as provided in CERCLA section 121(e),
42 U.S.C. § 9621(e). In addition, combination of
the Consolidation Areas and the Tailings
Disposal Area means that the action transferring
mine waste from the Consolidation Areas to the
Tailings Disposal Area will be an on-site action
that need not meet the requirements of the
procedures for planning and implementing off-
site response actions codified at 40 CFR §
300.440 (the "Off-site Rule"). In short, treating
the non-contiguous NECR and UNC Sites as
one for the purpose of disposing NECR mine
waste at the UNC Site "would be in the best
interests of achieving sound and expeditious
environmental cleanups." 55 Fed. Reg. 8666,
8691 (1990).
NRC License Amendment. Currently, United
Nuclear Corporation is addressing source
material and implementing on-site surface
reclamation actions at the UNC Site under the
direction of the NRC, pursuant to United
Nuclear Corporation's NRC license. Disposal of
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 4 of 69
mine waste from the NECR Site within the
Tailings Disposal Area at the UNC Site will
require acceptance by the NRC and is
contingent on an amendment of United Nuclear
Corporation's NRC license to allow for
disposal. NRC's agreement to amend the United
Nuclear Corporation's license to allow this
disposal will be necessary to fulfill step two as
outlined in the 2011 Non-Time-Critical
Removal Action Memorandum (see the second
paragraph of this document).
Removal Site Evaluation Report and EE/CA
adopted as RI/FS. This Surface Soil OU
Proposed Plan summarizes information that can
be found in greater detail in the Removal Site
Evaluation Report Northeast Church Rock Mine
Site (MWH, 2007; RSE), the Engineering
Evaluation and Cost Analysis Report Northeast
Church Rock Mine Site (EPA, 2009; EE/CA),
and other documents contained in the
Administrative Record file for the UNC Site.
The EPA has adopted the RSE and the EE/CA,
including without limitation the findings of the
RSE and the EE/CA, as the remedial
investigation and feasibility study for the
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008909
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surface soil OU remedial action at the UNC
Site. EPA and NMED encourage the public to
review these documents to gain a more
comprehensive understanding of the UNC Site,
NECR Site, and Superfund activities that have
been conducted.
The process of selecting a remedial action for a
NPL site includes a Remedial Investigation and
Feasibility Study (RI/FS). The purpose of the
RI/FS is to assess site conditions and evaluate
alternatives to the extent necessary to select a
remedy. Developing and conducting an RI/FS
generally includes the following activities:
project scoping, data collection, risk assessment,
treatability studies, and analysis of alternatives.
As explained in the following enumerated
paragraphs, the NECR EE/CA, which EPA has
adopted as the RI/FS for this UNC Site surface
soil OU fulfills the NCP requirements for an
RI/FS and the detailed analysis of alternatives.
Thus, an EE/CA serves an analogous function to
the RI/FS conducted for EPA remedial actions.
1) Remedial Investigation. As provided in
the NCP at 40 CFR § 300.430(d)(1), the
purpose of the remedial investigation is to
collect data necessary to adequately
characterize the site for the purpose of
developing and evaluating effective
remedial alternatives. To characterize the
site, the lead agency (in this case the lead
agency is EPA) shall, as appropriate,
conduct field investigations, including
treatability studies, and conduct a baseline
risk assessment.
The NECR EE/CA addresses site
characterization in Section 1.5 Source, Nature
and Extent of Contamination, which includes
the following sub-sections which describe field
investigations and studies of the NECR Site
mine waste—the waste that will be brought to
the UNC Site under EPA's preferred alternative:
• 1.5.1 Source: Radium and Uranium
Laden Mine Wastes
• 1.5.2 Areas of Concern
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 5 of 69
• 1.5.3 Soil Contamination
It is appropriate to use the information gathered
for the NECR EE/CA to characterize the release
that will be addressed at the UNC Site because
the mine waste characterized in the EE/CA is
the mine waste that will be brought to the UNC
Site.
Section 1.5 also includes subsection 1.5.5
Human Health Risk Evaluation which describes
the risk posed by the mine waste that is to be
brought to the UNC Site under EPA's preferred
alternative. If EPA were to undertake a baseline
human health risk assessment (BHHRA) for the
UNC Site as it exists today, based on previous
cleanup activities and ongoing monitoring data,
EPA anticipates that there would be no
significant risk. Consequently, a BHHRA for
the UNC Site would not provide useful
information. On the other hand, the human
health risk evaluation undertaken at the NECR
Site as part of the EE/CA provides pertinent
BHHRA information because it describes the
risk posed by the mine waste that EPA proposes
to bring to the UNC Site if no action were to be
taken to encapsulate or otherwise protect the
public from that mine waste. Accordingly, it is
more appropriate for EPA to rely on the Human
Health Risk Evaluation undertaken for the
NECR EE/CA than it would be for EPA to
undertake a BHHRA at the UNC Site.
2) Feasibility Study. As provided in the NCP
at 40 CFR § 300.430(e), the primary
objective of the feasibility study is to ensure
that appropriate remedial alternatives are
developed and evaluated such that relevant
information concerning the remedial action
options can be presented to a decision-maker
and an appropriate remedy selected. The
lead agency (the lead agency is EPA) may
develop a feasibility study to address a
specific site problem or the entire site. The
development and evaluation of alternatives
shall reflect the scope and complexity of the
remedial action under consideration and the
site problems being addressed. Development
008910
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of alternatives shall be fully integrated with
the site characterization activities of the
remedial investigation. The lead agency
shall include an alternatives screening step,
when needed, to select a reasonable number
of alternatives for detailed analysis.
For the UNC Site surface soil OU, the disposal
of the NECR mine waste at the UNC Site was
among the alternatives evaluated under the
screening criteria identified by the NCP at 40
CFR § 300.430(e)(7) (i.e., effectiveness,
implementability, and cost) in EPA's 2011 Non-
Time-Critical Removal Action Memorandum
for the NECR Site. That is, as appropriate, and
to the extent sufficient information was
available, the short and long-term aspects of the
criteria of effectiveness, implementability, and
cost were used to guide the development of the
alternatives considered for the disposal of the
NECR Site mine waste; thus, the NECR Site
2011 Non-Time-Critical Removal Action
Memorandum effectively applied the remedial
action screening criteria identified by the NCP
at 40 CFR § 300.430(e)(7) to the alternatives
considered. Those alternatives included the
alternative that EPA proposes as its preferred
alternative for the surface soil OU at the UNC
Site. The evaluation (i.e., the screening) of the
various alternatives is described in the NECR
EE/CA at section 4.0 Analysis of Alternatives.
In subsections 4.3, 4.4, 4.5, 4.6, and 4.7, the
screening criteria of effectiveness,
implementability, and cost are applied to each of
the alternatives considered. In NECR Site
EE/CA subsection 4.7, consolidation of the
NECR Site mine waste in disposal cells on the
UNC Site was evaluated for effectiveness,
implementability and cost—the three criteria
that the NCP prescribes for screening of
remedial action alternatives under 40 CFR §
300.430(e)(7).
3) Detailed analysis of alternatives. As part
of the NCP remedy selection process, a
detailed analysis shall be conducted on the
limited number of alternatives that represent
viable approaches to remedial action after
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 6 of 69
evaluation in the screening stage. The lead
and support agencies (at the UNC Site, EPA
and NMED are the lead and support
agencies, respectively) must identify their
applicable or relevant and appropriate
requirements (ARARs) related to specific
actions in a timely manner and no later than
the early stages of the comparative analysis.
The lead and support agencies may also, as
appropriate, identify other pertinent
advisories, criteria, or guidance (hereinafter
this material is referred to as TBC for "to be
considered") in a timely manner. This has
been done for the UNC Site, and the ARARs
and TBCs are listed in Table 1.
The part of the remedy selection process known
as the detailed analysis consists of an
assessment of individual alternatives against
each of nine evaluation criteria and a
comparative analysis that focuses upon the
relative performance of each alternative against
those criteria. The nine evaluation criteria are as
follows:
Threshold Criteria
1. Overall protection of human health and
the environment
2. Compliance with ARARs
Primary Balancing Criteria
3. Long-term effectiveness and permanence
4. Reduction of toxicity, mobility or volume
5. Short-term effectiveness
6. Implementability
7. Cost
Modifying Criteria
8. State acceptance
9. Community acceptance
In the NECR Site EE/CA, these nine criteria
were used to evaluate the various alternatives
for disposing of the NECR mine waste. The
disposal of NECR Site mine waste within
disposal cells in the Tailings Disposal Area at
the UNC Site was one of the alternatives
evaluated under the nine criteria. The parts of
the NECR Site EE/CA in which the alternatives
were evaluated under the nine evaluation criteria
can be found in the EE/CA at section 5.0
008911
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Comparative Analysis of Removal Action
Alternatives and its subsections.
After going through this remedy development
and selection process in the NECR Site EE/CA,
which in this particular case, as explained
above, has all the elements of the NCP remedial
action remedy selection process, EPA selected
disposal of the NECR mine waste in the
disposal cells in the Tailings Disposal Area at
the UNC Site. As explained in the 2011 Non-
Time-Critical Removal Action Memorandum,
however, that disposal is contingent upon
"issuance of an appropriate decision document
by EPA Region 6 consistent with the NCP, 40
CFR Part 300." As provided in the NCP at 40
CFR 300.430(e)(6), EPA must consider at least
a no-action alternative as part of the process of
selecting a remedy at an NPL site. Although a
no-action alternative was considered for the
NECR Site, the EE/CA did not consider a no-
action alternative for the UNC Site.
Accordingly, this Proposed Plan describes the
NCP-consistent analysis that EPA has
undertaken with respect to those two remedies:
1) no action to dispose of NECR mine waste at
the UNC Site, and 2) disposal of the NECR
mine waste within the disposal cells at the
Tailings Disposal Area at the UNC Site.
Public Comment. EPA is issuing this Surface
Soil OU Proposed Plan as part of its public
participation responsibilities under Section
300.430(f)(2) of the NCP. EPA, in consultation
with NMED, will consider the preferred
alternative as well as other alternatives
presented in this Surface Soil OU Proposed Plan
and will select the final remedy for the surface
soil OU remedial action at the UNC Site after
reviewing and considering all information
submitted during the 60-day public comment
period. EPA, in consultation with NMED, may
modify the response action presented in this
Surface Soil OU Proposed Plan based on new
information or community comments including
comments of Navajo tribal members and the
Navajo Nation Environmental Protection
Agency (NNEPA). Therefore, the public is
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 7 of 69
encouraged to review and comment on this
Surface Soil OU Proposed Plan.
SITE BACKGROUND
Location
The UNC Site is a non-operating uranium mill
located approximately 17 miles northeast of
Gallup, New Mexico, in McKinley County
(Figure 1). The UNC Site is generally
comprised of the former ore processing mill
facilities and a byproduct material (i.e., tailings)
disposal area (hereinafter, Tailings Disposal
Area: Figure 4), which cover about 25 and 100
acres, respectively. The UNC Site is owned by
United Nuclear Corporation and is located
within Section 2, Township 16 North, Range 16
West (EPA, 1988b). In addition to Section 2,
United Nuclear Corporation owns the land
located northeast of the UNC Site Tailings
Disposal Area that is within Section 36,
Township 17 North, Range 16 West and is
bounded on the north by the Navajo Nation
Indian Reservation (Figure 4). Sections 2 and 36
represent the Site Boundary. The area around
the UNC Site is sparsely populated and includes
Indian tribal trust land and Indian allotted land.
To the north of the UNC Site is another former
uranium mine identified as Northeast Church
Rock Quivira Mine Site (Figure 1). This is a
non-NPL site that is being addressed by EPA
under a separate action.
The NECR Site is a non-operating uranium
mine located within Sections 34 and 35 of
Township 17 North, Range 16 West and Section
3 of Township 16 North, Range 16 West at the
termination of State Highway 566,
approximately 17 miles northeast of Gallup,
New Mexico, in McKinley County (Figure 1). It
is just northwest of the UNC Site less than about
one mile away. The NECR Site is located within
an area of approximately 125 acres, the greater
part of which is located on lands held by the
United States in trust for the Navajo Nation
(EPA, 2011b).
According to the Red Water Pond Road
Community Association, there are eleven
008912
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households or home sites in the immediate
vicinity of the NECR and UNC Sites, including
48 families and 110 people (Figure 1).
Approximately 25 families reside along Pipeline
Road north of the UNC Site and approximately
12 families reside along State Highway 566
south of the UNC Site (EPA, 2009). Several
Navajo families have stated they collect herbs
and plants from the NECR Site and surrounding
area for ceremonial purposes. Apart from the
residential areas, the primary land use in the
area around the NECR Site and the UNC Site is
grazing for sheep, cattle, and horses. The nearest
ground water well is located 1.7 miles northeast
of the perimeter of the UNC Site and four
known operating wells are located within a four
mile radius of the UNC Site (EPA, 1988b).
Operation
The NECR Site is a historic uranium mine that
was operated by United Nuclear Corporation.
Following extensive uranium mineral
exploration in the 1950s and 1960s, mining
development began at the NECR Site in 1967
and ended in 1982. From approximately 1969 to
1986, large quantities of ground water were
pumped from the NECR mine and from the
Quivira mines to dewater the underground mine
workings (EPA, 201 lb). This mine water was
discharged to the local arroyo (known as
Pipeline Arroyo), which runs across the UNC
Site (Figures 1 and 4). A portion of the mine
discharge water infiltrated into the subsurface
and significantly re-saturated the near-surface
alluvium and Zone 1 and Zone 3 of the Upper
Gallup Sandstone Formation, creating an
artificially high water table beneath the UNC
Site (EPA, 2008).
The UNC Site includes a historic uranium mill
that was licensed to operate by the State of New
Mexico in May 1977. The mill operated from
1977 to 1982, and processed ore primarily from
two of United Nuclear Corporation's nearby
mines: Northeast Church Rock and Old Church
Rock. Uranium ore was processed at the facility
using a combination of crushing, grinding, and
acid-leach solvent extraction methods. The
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 8 of 69
milling operation produced acidic slurry of
ground rock and fluid (tailing) that was pumped
into the Tailings Disposal Area which consists
of three cells (Figure 4). An estimated 3.5
million tons of tailings were disposed in the
tailings impoundments (EPA, 1988a).
Previous Actions
History of EPA involvement at the UNC Site
EPA placed the UNC Site onto the National
Priorities List (NPL) of Superfund sites in 1983
[48 Fed. Reg. 40658 (Sept. 8, 1983)] because
contaminated liquids had seeped from the
tailings at the UNC Site and contaminated the
underlying ground water, and because there
were toxic emissions to surface water and air
(EPA, 1988b). Acidic liquids had seeped from
the tailings located in the unlined disposal cells
into the underlying alluvium deposits (referred
to as the Southwest Alluvium) and also into two
deeper zones (Zones 1 and 3) of the Upper
Gallup Sandstone Formation, contaminating the
ground water with heavy metals, radionuclides
such as uranium and radium, and other chemical
constituents.
In 1986, the NRC assumed responsibility for the
licensing and regulating of uranium mills within
the State of New Mexico at the request of the
Governor.
In 1988, EPA and NRC signed a Memorandum
of Understanding (MOU) regarding the UNC
Site [53 Fed. Reg. 37887 (September 28,
1988)]. The EPA and the NRC have overlapping
authority in connection with the UNC Site, and
the MOU was developed to help assure that
remedial actions occur in a timely and effective
manner. As stated in the MOU, NRC assumed
the role of lead regulatory agency for the
byproduct material disposal area (i.e., the
Tailings Disposal Area) reclamation and closure
activities with EPA monitoring all such
activities and providing review and comments
directly to NRC while EPA developed and
implemented its own site action requirements
for ground water contamination outside of the
Tailings Disposal Area in accordance with
008913
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CERCLA and the NCP. NRC's actions at the
UNC Site are taken pursuant to the Source
Materials License SUA-1475 (License) and the
Uranium Mill Tailings Radiation Control Act of
1978, 42 U.S.C. §7901 et seq. As stated in the
MOU, EPA may take remedial actions on the
UNC Site in order to fulfill its regulatory
requirements. In keeping with the MOU, EPA
has consulted with the NRC prior to issuing this
Surface Soil OU Proposed Plan.
After the UNC Site was listed on the NPL, EPA
conducted a ground water Remedial
Investigation and a Feasibility Study from 1984
through 1988. Based on the remedial
investigation findings, ground water in the
Southwest Alluvium, Zone 1, and Zone 3 had
been contaminated by acidic tailings seepage.
EPA issued a Ground Water Operable Unit
Record of Decision (ROD) in September 1988
selecting a remedy for the contaminated ground
water that included extraction of the ground
water and treatment by evaporation. Extraction
wells were completed in the Southwest
Alluvium, Zone 1, and Zone 3 downgradient of
the Tailings Disposal Area. The remedy selected
in the 1988 ROD also included ground water
monitoring in the Southwest Alluvium, Zone 1,
and Zone 3. EPA identified United Nuclear
Corporation as a potentially responsible party
(PRP) under CERCLA. EPA issued a CERCLA
Unilateral Administrative Order (UAO; Docket
No. CERCLA 6-11-89) to United Nuclear
Corporation, calling for United Nuclear
Corporation to implement the remedy as
selected in the ROD. The PRP constructed the
remedy in 1989, and continues to address
ground water contamination under the 1988
ROD. Ground water monitoring and extraction
wells are located at the boundary and
downgradient of the Tailings Disposal Area.
Ground water monitoring and remediation of the
contaminant plumes are ongoing and are being
conducted by United Nuclear Corporation under
the 1988 ROD. Ground water is not a
component of this Surface Soil OU Proposed
Plan, which addresses only the proposed
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 9 of 69
disposal of the NECR Site low level threat mine
waste at the UNC Site.
History of the NRC and NMED actions at the
UNC Site
United Nuclear Corporation undertook the
following actions under its NRC License (EPA,
2008). On July 16, 1979, the dam at the south
tailings disposal cell at the UNC Site failed
sending tons of radioactive tailings waste and
approximately ninety-three million gallons of
contaminated liquid into the Rio Puerco. The
flood left behind radioactive contaminants as
well as hazardous heavy metal contamination,
and contaminated the Rio Puerco. United
Nuclear Corporation repaired the dam shortly
after its failure, and cleanup of the resultant spill
was conducted according to criteria imposed by
state and federal agencies at that time.
Under the direction of NMED, initial corrective
actions to address ground water concerns began
with tailings seepage investigations and
neutralization of the acidic tailings. These
actions were performed from 1979 through
1982. Tailings neutralization included the
addition of ammonia and lime to the tailings.
The NMED also required that United Nuclear
Corporation remediate ground water in Zones 1
and 3. This remediation began in 1982 and
consisted of installing and operating wells to
extract tailings seepage, neutralizing the
extracted water, and discharging the neutralized
water into the tailings disposal cells (EPA,
1988b).
In 1986, the NRC assumed responsibility for the
licensing and regulating of uranium mills within
the State of New Mexico. United Nuclear
Corporation submitted a draft reclamation plan
to NRC in 1987 and the final plan was approved
in March 1991 (Canonie, 1991). The NRC
required decommissioning of the mill facility,
remediation of radium 226 (Ra-226)
contaminated soil, capping of the tailings cells,
installation of extraction wells, and construction
of evaporation ponds and an evaporation
system. Some of the key actions that were
008914
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completed included final remediation of
windblown tailings from Sections 2 and 36 in
1989 (United Nuclear Corporation, 1989), final
remediation of windblown tailings from Section
1 in 1990 (United Nuclear Corporation, 1990),
mill decommissioning in 1992 (United Nuclear
Corporation, 1993), final reclamation of the
North Cell in 1993 (Canonie, 1995), final
reclamation of the Central Cell in 1994
(Canonie, 1995), and final reclamation of the
South Cell in 1995 (Smith Environmental,
1996a). Construction of surface water control
structures around the perimeter of the Tailings
Disposal Area was completed in 1996 (Smith
Environmental, 1997). As stated in this 1996
report, the final remaining reclamation actions
include backfilling of the evaporation ponds,
capping of the evaporation pond area, and
completion of the final drainage swales at the
Tailings Disposal Area. The evaporation ponds
are currently used and are a part of the ongoing
ground water cleanup. Therefore, these final
reclamation actions will be completed after
remedial actions related to this surface soil OU
proposed action are completed and the
evaporation ponds are no longer necessary for
ground water cleanup.
History of EPA involvement at the NECR Site
United Nuclear Corporation undertook closure
activities between 1986 and 1988 under the
NRC Source Materials license for the UNC Site
including the closure of the ion exchange plant,
removal of sludge from the mine water
treatment ponds, and closure of the tailings sand
backfill areas. Radionuclide contaminated soil
and tailings sand from the NECR Site were
disposed at the UNC Site in conjunction with
UNC mill decommissioning and reclamation
activities. The NRC certified these closure
actions in 1989 and released the license areas of
the mine for unrestricted use (NRC, 1989).
The NECR Site is not on the NPL, and is
currently subject to EPA removal actions
(Figure 1). Consultations with the Navajo
Nation and the State of New Mexico in 2005
resulted in EPA taking the lead on the NECR
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 10 of 69
Site. NNEPA sent a letter to EPA dated March
22, 2005, formally requesting that EPA become
the lead agency, and EPA issued a letter
formally accepting NECR Site lead on
November 7, 2005 (EPA, 2011b).
EPA ordered a Removal Site Evaluation (RSE)
investigation, three time-critical removal actions
and one non-time-critical removal action related
to the NECR Site in the past five years. United
Nuclear Corporation was identified as the PRP,
and performed the investigation and these
removals with EPA, as described below (EPA,
2011b).
In September 2006, EPA entered into an
Administrative Order on Consent (AOC) with
United Nuclear Corporation. United Nuclear
Corporation performed a RSE at the NECR Site
and a Supplemental RSE, under oversight by
EPA and NNEPA. The RSE report and the
Supplemental RSE report were issued in
October 2007 (MWH, 2007) and February 2008
(MWH, 2008), respectively.
On April 18, 2007, EPA issued the NECR Site
Residential Action Memorandum, which called
for the cleanup of contamination in residential
areas located near the NECR mine. On May 4,
2007, EPA issued a unilateral administrative
order (UAO) to the United Nuclear Corporation.
The UAO required United Nuclear Corporation
to perform the cleanup described in the NECR
Site Residential Action Memorandum. Under
the terms of the UAO, United Nuclear
Corporation was required to transport and
dispose of contaminated soil that had been
excavated from the residential areas by EPA.
EPA also conducted the sampling to determine
the areas that needed to be addressed. Using the
EPA-established soil cleanup goal of 2.24
picocuries3 per gram (pCi/g) Ra-226, removals
3 Throughout this Surface Soil OU Proposed Plan, the term
picocurie is used to indicate the radiation associated with the
contaminants present. Radioactive elements are unstable and
become other elements known as "daughters" by giving off
008915
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were conducted for half-acre areas around four
home sites consistent with the Multi-Agency
Radiation Survey and Site Investigation Manual
guidance and procedures (EPA, 201 lb).
The RSE and Supplemental RSE reports
identified conditions that indicated an additional
removal action (i.e., in addition to the NECR
Site Residential Removal Action) will be
necessary to reduce or eliminate threats to
human health and the environment. Based on
this finding, the EPA issued an Engineering
Evaluation and Cost Analysis (EE/CA) Report
on May 30, 2009 (EPA, 2009). An EE/CA
identifies the objectives of the removal action
and analyzes the effectiveness,
implementability, and cost of various
alternatives that may satisfy these objectives.
The EE/CA for the NECR Site evaluated
removal action alternatives for the NECR Site
considering the nature of the contamination,
potential risks to human health and the
environment, and whether the alternatives were
protective considering future land use plans.
The EE/CA for the NECR Site identified the
removal action objectives, described five
removal action alternatives, and assessed the
effectiveness, implementability, and cost of
each of the five alternatives.
EPA signed the NECR Step-Out Area Interim
Removal Action Memorandum on July 23,
2009. Under a July 24, 2009, Administrative
Order on Consent (AOC) issued by EPA, United
Nuclear Corporation and General Electric
(UNC/GE) agreed to undertake the removal
action with EPA oversight. The 2009 removal
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 11 of 69
action used 2.24 pCi/g Ra-226 as a cleanup
goal. This was the same cleanup goal selected
for the 2007 NECR Site Residential Removal
Action. The work under the AOC included
demolition of existing mine buildings and
associated concrete slabs located within the
NECR-14 footprint; excavation and placement
onto the NECR-1 pile of approximately 109,800
cubic yards of soil from the Interim Removal
Step Out Area5 (Figure 1-Step Out Area #1),
including approximately 33,000 cubic yards
from the on-site arroyo known as the Unnamed
Arroyo (Figure 3); excavation and stockpiling of
approximately 4,000 cubic yards of
contaminated soil; backfilling and restoration of
depressions, culverts, and roads with new
imported materials; characterization of Red
Water Pond Road from Highway 566 to the
bridge by the Northeast Church Rock Quivira
Mine Site (Figure 1); and fencing, seeding and
other restoration activities (EPA, 2011b).
In response to additional supplemental RSE
work conducted in the spring of 2011, EPA
signed the NECR Time-Critical Removal
Action Memorandum for the Drainage East of
Red Water Pond Road (Step Out Area #2) on
September 26, 2011 (Figure 1-Step Out Area
#2). It is anticipated that UNC/GE will enter
into an agreement with EPA to undertake the
removal action with EPA oversight. In
accordance with the NECR Time-Critical
Removal Action Memorandum, the removal
action will use the same cleanup goal of 2.24
pCi/g Ra-226 that was used during the 2007 and
2009 Removal Actions. The work will include
excavation and placement onto the NECR Site
radiation. When one atom of an element becomes its daughter,
this is known as "decay". The curie (symbol Ci) is a unit of
radioactivity, defined as 1 Ci = 3.7* 1010 or 37,000,000,000
decays per second. This is roughly the activity of 1 gram of the
radium isotope 226Ra, a substance studied by the pioneers of
radiology, Marie and Pierre Curie, for whom the unit was
named. Pico here means one trillionth. A picocurie (pCi) is one
trillionth of the decays per second expected from a gram of the
radium isotope 226Ra. This turns out to be about 2.2 decays per
minute.
4 NECR 1 and 2 pads were concrete slab areas that held the ore
(including low-grade ore) that was mined from the NECR Mine.
The stockpiled ore was then transported from NECR 1 and 2
pads to the UNC Mill for processing. Former mining facility
buildings were also located in the NECR 1 area until they were
demolished in 2009. However, the material resulting from the
demolition remains on the NECR Site.
5 The part of the NECR Site that is located to the north and east
ofNECR Site and identified as Step Out Area #1 on Figure 1.
008916
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of approximately 30,000 cubic yards of soil
from the area east of Red Water Pond Road.
During all previously mentioned removal
actions and in close coordination with EPA
Community Involvement Coordinators,
UNC/GE arranged for temporary housing for
three households for approximately five months.
EPA also temporarily moved residents from six
additional households for approximately two
months.
EPA provided a 90-day public comment period
for the NECR EE/CA and received numerous
written public comments. During the comment
period, EPA held one public meeting (June 23,
2009) and two public hearings (July 7, 2009 and
August 25, 2009). All public meetings, hearings,
and dates of the comment period and its
extension were advertised in the Gallup
Independent and the Navajo Times. After the
official public comment period ended, EPA
continued community involvement efforts
during the following 24 months to listen and
respond to community, stakeholder and Navajo
Nation concerns. During this time frame, EPA
conducted ten additional community events,
including meetings, site tours, and workshops.
Over this extended 24 month period, EPA
performed additional data analyses based on
community comments and concerns received.
EPA performed additional evaluations on 11
alternate disposal locations that could
potentially be used for disposal of the NECR
Site mine waste (EPA, 201 la). These alternate
locations included licensed facilities, current
Uranium Mill Tailings Radiation Control Act of
1978 (UMTRCA) Sites with similar mine waste
disposal, and locations where new licensed
facilities potentially could be built (EPA,
201 la). As EPA reviewed the possible locations
where the NECR Site mine waste could be
disposed, EPA looked at the condition of the
location in question, and EPA researched the
legal and regulatory standards that would impact
whether additional disposal could occur at the
location in question. After consideration of the
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 12 of 69
administrative, legal and cost challenges
presented by each of the 11 alternate locations
reviewed, the UNC Site was identified as the
most suitable (EPA, 2011a). In addition, as
explained in the EE/CA and summarized in the
2011 Non-Time-Critical Removal Action
Memorandum for the NECR Site (EPA, 201 lb),
on-site disposal of the NECR Site mine waste at
the NECR Site was rejected by the Navajo
Nation and the community6.
The EPA and the other regulatory agencies
involved in the NECR cleanup share the
community's concerns that the design of the
NECR disposal cells at the UNC Site be robust
enough to protect against any migration of
contamination to the surrounding land, air,
surface water, or ground water. As a result,
various locations, other than the Tailings
Disposal Area and within the boundary of the
UNC Site, were evaluated to determine if these
locations could be used for disposal. Two areas
on the UNC Site were identified as potentially
large enough to accommodate the volume of
mine waste expected to be excavated from the
NECR Site. One location considered is found
just to the northeast of the Tailings Disposal
Area's North Cell (Figure 4). Disposal in this
location would not be acceptable as it would
require the plugging and abandonment of all
wells associated with the ongoing ground water
remedial action. The second location considered
lies within the decommissioned UNC Mill
Facility (Figure 4). EPA found the UNC Mill
Facility area to be too small to accommodate the
estimated volume of the NECR Site mine waste
that must be disposed there (EPA, 2010). In
such a small area, disposal and capping
activities would have required a slope too steep
to maintain for proper mine waste containment.
The UNC Mill Facility location also presented
6 In EPA's Action Memorandum for the Non-Time Critical
Removal Action at the NECR Site (September 2011), EPA
rejected any disposal on the NECR Site because of the
objections of the Navajo Nation and the local community.
008917
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additional challenges for long-term
protectiveness given its proximity to Hwy 566.
In response to concerns raised by the
community, EPA reviewed documents related to
the construction of the Tailings Disposal Area,
in order to determine the load effect that the
additional mine waste from the NECR Site
would have on the tailings already disposed in
the Tailings Disposal Area. Further, at the
request of EPA, United Nuclear Corporation
developed computer models that simulated what
would happen to the tailings in the Tailings
Disposal Area under various scenarios (Dwyer,
2011). The models showed that, due to
evapotranspiration, vertical drainage and the
lack of water recharge, excess free water no
longer existed within the tailings now located in
the Tailings Disposal Area. The modeling
indicated that the remaining water in the tailings
now located in the Tailings Disposal Area is
within the water storage capacity of the tailings
and will be held within the pore spaces. Any
reduction in the tailings' soil porosity due to the
loading or weight of the additional NECR mine
waste is not expected to create excess or new
free water that could be "squeezed" out. Based
on conservative evaluations of the tailings
profiles and model sensitivity analyses, adding
the mine waste from the NECR Site to the
tailings in the Tailings Disposal Area at the
UNC Site is not expected to result in the release
of additional tailings liquid into the ground
water or surrounding soil. Based on these
conclusions, disposal of the NECR Site mine
waste at the UNC Site Tailings Disposal Area is
not expected to interfere with or affect the
ongoing remediation efforts regarding tailings
or ground water at the UNC Site. EPA
recognizes the limitations of the simulations and
model results. During remedial design,
additional data will be collected and evaluated
to further refine, support, and verify these
conclusions.
EPA also reviewed the Mill Decommission
Report (UNC, 1993) and the Borrow Pit No. 2
Final Reclamation Report (Smith, 1996b).
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 13 of 69
These reports documented the placement of the
debris (e.g., concrete, steel, and wood) within
the Tailings Disposal Area. Based on this
documentation, it appears that the debris was
placed in the Tailings Disposal Area in layers,
flattened, mixed and covered with soil, and
compacted resulting in a stable cell that has had
negligible settling over the almost 20 years
since disposal. Consequently, it is expected that
the additional weight that the mine waste from
the NECR Site will add to the tailings that are
presently in the UNC Site Tailings Disposal
Area will have negligible consequences on the
stability of the tailings cells (EPA, 2011b).
Placement of mine waste within the Tailings
Disposal Area will be designed and constructed
in such a manner that promotes material
stability and reduces the potential for future
subsidence.
Following this extensive EE/CA public
involvement process, EPA signed the 2011
Non-Time-Critical Removal Action
Memorandum for the NECR Site on September
29, 2011. EPA responded to all public, State,
and Navajo Nation comments in a
Responsiveness Summary provided as
Attachment III to the 2011 Non-Time-Critical
Removal Action Memorandum (EPA, 201 lb).
The removal action described in the 2011 Non-
Time-Critical Removal Action Memorandum
calls for the excavation of mine waste from the
NECR Site and placement of the mine waste at
a location or a facility that EPA determines to
be acceptable for the receipt of CERCLA waste
under applicable laws. Using the information
gained during the public involvement process
and presented in the Responsiveness Summary,
the location selected for disposal in the 2011
Non-Time-Critical Removal Action
Memorandum, is the nearby UNC Site. Disposal
at the UNC Site, however, is contingent upon
both issuance of an appropriate decision
document for the UNC Site consistent with the
NCP, 40 CFR Part 300 (Step 1), and
modification of the license issued by the NRC
for the UNC Site (Step 2).
008918
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SITE CHARACTERISTICS
UNC Site
At the UNC Site, there are two agencies with
overlapping jurisdiction—EPA and NRC. As
stated in the MOU, NRC assumed the role of
lead regulatory agency for the Tailings Disposal
Area reclamation and closure activities with
EPA monitoring all such activities and
providing review and comments directly to
NRC while 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
NCP.
Ground Water
The Remedial Investigation Report (EPA,
1988a) discussed ground water contaminant
sources and migration pathways at the UNC
Site. Two major sources of recharge to the UNC
Site aquifers were identified: infiltration of
surface water within Pipeline Arroyo during
mine water discharge and tailings seepage water
from the active Tailings Disposal Area (Figure
4). To a lesser extent, direct precipitation
supplies recharge water to the aquifers.
The UNC Site is underlain by three aquifers.
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 14 of 69
From the geologically youngest to the oldest,
these units are referred to as: (1) Southwest
Alluvium (unconsolidated materials along
Pipeline Arroyo, having a maximum thickness
of approximately 150 feet (ft) and a maximum
width of approximately 4,000 ft); (2) Zone 3
(uppermost stratigraphic unit of the Upper
Gallup Sandstone, having a thickness of 70 to
90 ft in the area of the Tailings Disposal Area);
and (3) Zone 1 (lowest stratigraphic unit of the
Upper Gallup Sandstone, having a thickness of
80 to 90 ft in the area of the Tailings Disposal
Area). In some areas, Zones 1 and 3 are in
contact with the alluvium at the Tailing
Disposal Area. Zone 1 and Zone 3 are separated
by Zone 2. Zone 2 is a unit of coal and shale
approximately 15 to 20 ft thick which acts as an
aquiclude, strongly inhibiting vertical water
migration from Zone 3 to Zone 1 (EPA, 2008;
Figure 5).
From approximately 1969 to 1986, the large
quantities of ground water pumped from the
NECR and Quivira mines to dewater the
underground mine workings (EPA, 201 lb) was
discharged to Pipeline Arroyo, which runs
across the UNC Site (Figures 1 and 4). A
portion of the mine discharge water, estimated
at up to 250
gallons per
minute (EPA,
1988a),
infiltrated into
the subsurface
and
significantly re-
saturated the
Southwest
Alluvium, Zone
3, and Zone 1
creating an
artificially high
water table
beneath the
UNC Site (EPA,
2008).
base of tailings
(approximate)
Alluvium
ground surface
<2 8900-
w
c
0
1
> 88KH
i
Zone 3
Zone 1
Dilco
670th
500 1000 1600
Distance (feet)
2x vertical exaggeration
FIGURES
Northwest-looking view across the North Cell
2000
2500
Adopted from Figure 2 of the Technical
Memorandum Summarizing Two Reports on
Zone 3 Tailings Seepage Sourcing and
Groundwater Recharge, with Information
Update United Nuclear Corporation's
Church RockTailings Site, Gallup, New
Mexico by Chester Engineers for United
Nuclear Corporation.
008919
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In addition to mine water infiltration through
Pipeline Arroyo, tailings seepage water from the
active Tailings Disposal Area infiltrated and
contaminated all three aquifers. Seepage of
tailings liquids entered the Southwest Alluvium
from the three Tailings Disposal Area cells to
varying degrees. The mechanism responsible for
this transport is gravity flow of water through
the tailings into the Southwest Alluvium. Where
the Southwest Alluvium is absent, tailings
seepage has entered Zone 3 in the northeastern
portion of the North Cell where Zone 3 contacts
the tailings and Zone 1 in the eastern portion of
the Central Cell where Zone 1 contacts the
tailings (EPA, 1988b).
By 1986, all mine dewatering activity had
ceased. With the cessation of mine dewatering,
ground water recharge from this surface water
source through Pipeline Arroyo no longer
occurs (except during precipitation events).
Water levels in all three aquifers have continued
to decline. Current ground water levels in the
Southwest Alluvium, Zone 3, and Zone 1 are
below the bases of the Tailings Disposal Area
cells. Water level data from October 2002 show
as much as 40 to 70 ft of unsaturated alluvium
separating the tailings deposits from the ground
water present in the Southwest Alluvium
(USFilter, 2004). Water level data from October
2003 show at least 60 ft of unsaturated material
separates the bottom of the tailings from the
ground water found in Zone 3 (USFilter, 2004).
Water level data from October 2012 show as
much as 17 to 29 ft of unsaturated material
separating the tailings deposits from the ground
water present in Zone 1 (Chester, 2012).
Presently, these conditions remain unchanged
and without a substantial rise in the water table,
contact between the ground water and the
tailings will not occur (Chester, 2011).
In short, since mine dewatering ceased
upgradient of the Tailings Disposal Area, and
since the tailings cells were reclaimed, the
ground water table lies as much as 17 to 70 ft
below the disposal cells in the Tailings Disposal
Area. This is important because it means that
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 15 of 69
mine waste from the NECR Site can be stored in
the cells at the Tailings Disposal Area without
direct contact with the ground water. In
addition, modeling of the tailings showed that,
due to evapotranspiration, vertical drainage and
the lack of water recharge, excess free water no
longer exists within the tailings now located in
the Tailings Disposal Area (Dwyer, 2011). The
remaining water in the tailings now located in
the Tailings Disposal Area is within the water
storage capacity of the tailings and will be held
within the pore spaces. Any reduction in the
tailings' soil porosity due to the loading or
weight of the additional NECR mine waste will
not create excess or new free water that could be
"squeezed" out. Based on conservative
evaluations of the tailings profiles and model
sensitivity analyses, adding the mine waste from
the NECR Site to the tailings in the Tailings
Disposal Area at the UNC Site is not expected
to result in the release of additional tailings
liquid into the ground water or surrounding soil.
Based on these conclusions, disposal of the
NECR Site mine waste at the UNC Site Tailings
Disposal Area is not expected to interfere with
or affect the ongoing remediation efforts
regarding tailings or ground water at the UNC
Site. EPA recognizes the limitations of the
simulations and model results. During remedial
design, additional data will be collected and
evaluated to further refine, support, and verify
these conclusions.
Extraction and evaporation of contaminated
ground water to remove contamination was
selected as the ground water remedy for the
UNC Site and documented in the 1988 EPA
ROD. Ground water monitoring and extraction
wells are located at the boundary and
downgradient of the Tailings Disposal Area.
Ground water monitoring and remediation of the
contaminant plumes are being conducted by
United Nuclear Corporation, are ongoing, and
will continue under the 1988 ROD as a separate
remedial action. Ground water is not a
component of this Surface Soil OU Proposed
Plan, which addresses only the proposed
disposal of the NECR Site low level threat mine
008920
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waste at the UNC Site. Mine waste disposal
within the Tailings Disposal Area is not
expected to interfere or affect the current ground
water remediation efforts. Mine waste disposal
will be designed and constructed to provide for
continued protection against contaminant
migration into the ground water (see Summary
of Remedial Alternatives section) in support of
ongoing ground water remediation efforts.
Tailings Disposal
The UNC mill was designed to process 4,000
tons of ore per day. The UNC mill used a
conventional crushing, grinding, and acid leach
solvent extraction method to extract uranium.
The average ore grade processed at the mill was
approximately 0.12 percent U3O8 (EPA, 1988).
The crushing, grinding, and milling processes
produced tailings that were an acidic waste of
ground ore and fluid. An estimated 3.5 million
tons of tailings were disposed in the unlined
impoundments (EPA, 1988) located within the
Tailings Disposal Area.
During the development of the Tailings
Reclamation Plan (Canonie, 1991), United
Nuclear Corporation's contractor, Canonie
Environmental Services Corp. (Canonie),
conducted extensive field investigations to
develop a comprehensive reclamation plan.
Based on characterization data collected from
the uranium ore in 1976, the mineral
composition of the ore host rocks was
determined to consist of 78 to79 percent quartz,
2 to 3 percent calcite, and 18 to 20 percent
kaolinite and feldspars. Accordingly, the tailings
would be expected to approximately reflect
these coarse to fine ratios of about 80 percent
coarse tailings (quartz/calcite) and 20 percent
fine tailings (kaolinite/feldspars: Canonie,
1991).
The coarse tailings typically produce lower
radon emissions than the fine grained fraction.
Field investigation data collected in 1986
showed the coarse tailings to have a range of
108 to 227 pCi/g radium with an average radium
content of 154 pCi/g. Data for the fine-grained
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 16 of 69
tailings showed a range of 285 to 1099 pCi/g
radium with an average radium content of 547
pCi/g. From 1993 through 1995 and in
accordance with the Tailings Reclamation Plan,
United Nuclear Corporation's contractors
performed reclamation action for the Tailings
Disposal Area. During reclamation actions, the
tailings were regraded so that coarse tailings or
other material (i.e., windblown tailings) covered
the fine-grained tailings to provide a minimum
seven-foot thickness of coarse tailings over the
fine-grained tailings. The purpose was to
minimize radon emissions from the tailings and
reduce the amount and thickness of soil that
would be needed to cover the Tailings Disposal
Area, including the coarse tailings which were
placed on top of the fine tailings. The tailings
disposal cell caps were constructed using 18 to
24 inches compacted soil which was overlain
with 3 inches of rock mulch. The final layer
consisted of compacted soil.
NECR Site
The NECR Site consists of two mine shafts, two
uranium ore waste piles, and several mine vent
holes. Operations at the NECR Mine left
uranium protore (low grade ore), waste rock,
and overburden after the mine was shutdown.
The mine wastes consists of uranium-bearing
waste rock that produces uranium daughter
products during decay7, in particular radium.
The decay process releases alpha, beta, and
gamma radiation. Radium can be found in air
and soil and produces airborne radon gas. For
the purposes of this Surface Soil OU Proposed
Plan, the term mine waste refers to NECR Site
7 In nuclear science, the decay chain refers to the radioactive
decay of different discrete radioactive isotopes. Decay occurs
when these isotopes emit particles. Most radioactive isotopes do
not decay directly to a stable state, but rather undergo a series of
decays until eventually a stable isotope is reached. Decay stages
are referred to by their relationship to previous or subsequent
stages. A parent isotope is one that undergoes decay to form a
daughter isotope. The daughter isotope may be stable or it may
decay to form a daughter isotope of its own. The intermediate
stages often emit more radioactivity than the original isotope.
One of uranium's daughter products is the more radioactive Ra-
226.
008921
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soil that is contaminated with hazardous
substances that are either radioactive or heavy
metals.
During the 2006 RSE field investigation of the
NECR Site, United Nuclear Corporation
performed scan and static gamma surveying and
surface [<0.5 feet below ground surface (ft bgs)]
and subsurface (>0.5 ft bgs) soil sampling. The
results of the gamma radiation surveys and soil
sampling indicated that surface and subsurface
soil contain high concentrations of Ra-226 and
uranium. For surface soil, Ra-226 values ranged
from 0.8 to 875 pCi/g and uranium values
ranged from 0.7 to 3,970 milligrams per
kilogram (mg/kg). For subsurface soil, Ra-226
values ranged from 0.6 to 438 pCi/g and
uranium values ranged from 0.7 to 760 mg/kg.
Soil sample results indicated that other stable
metals such as molybdenum, selenium and
vanadium were present. The sampling results
showed that concentration levels of these metals
were either below human health screening
levels8 or appeared to be within the
concentration range observed in the background
area and do not appear to be associated with
mining or milling operations. Exceptions to this
occurred at only one operational area, NECR-1,
where selenium was detected at a concentration
above background but below the human health
screening level. There were four detections of
molybdenum concentrations above background
(an undetectable concentration of molybdenum
was defined as "non-detect" for background) but
below the human health screening level at
NECR-1.
8 Soil screening is a tool developed by EPA to help standardize
and accelerate the evaluation and cleanup of contaminated soils
where future residential land use is anticipated. Soil screening
levels are contaminant concentrations which EPA uses to
identify areas needing further investigation. That is, if EPA
finds contaminant concentrations that exceed screening levels in
part of a contaminated site, EPA will take a closer look at that
area, conducting more sampling to determine whether there are
contaminants in that part of the site that should be remediated.
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 17 of 69
Arsenic was also detected in surface soil at
concentrations ranging from non-detect to 14.9
mg/kg, and it was detected in the subsurface soil
at concentrations ranging from non-detect
(<0.5) to 13.9 mg/kg. All sampling results found
arsenic soil concentrations to be at levels below
screening levels that EPA uses to determine
whether there would be a human health risk
associated with residential use of the area tested
due to the toxicity of arsenic that is not
associated with arsenic's carcinogenic
properties.9
Based on the results from the gamma radiation
surveys and soil sampling conducted by United
Nuclear Corporation, there is an estimated
871,000 cubic yards of mine waste at the NECR
Site that is to be addressed. The following
former operational areas were identified in the
2011 Non-Time-Critical Removal Action
Memorandum as areas of concern for mine
waste contamination at the NECR Site and are
referred to collectively as the Consolidation
Areas in this Surface Soil OU Proposed Plan
(Figure 3; EPA, 2011b):
• NECR 1 and NECR 2. NECR 1 and 2 pads
were concrete slab areas that held the ore
(including low-grade ore) that was mined
from the NECR Mine. The stockpiled ore
was then transported from NECR 1 and 2
pads to the UNC Mill for processing.
Former mining facility buildings were also
located in the NECR 1 area until they were
demolished in 2009. However, the material
resulting from the demolition remains on the
NECR Site.
• NECR-1 " Step-Out Area". The part of the
NECR Site that is located to the north and
east of NECR-1 is identified as the step-out
area. The Step-Out Area includes the former
trailer park, former fuel storage area,
9 Arsenic is both a systemic toxin and a carcinogen. The
screening level used here looked at the risk to human health
posed by arsenic as a systemic toxin.
008922
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sediment pond, ion exchange plant, and
other areas containing mine waste.
• Sandfills 1, 2 & 3. During closure of the
UNC Mill, the sandfill areas were used as
temporary staging grounds for tailings
material that had been processed through the
UNC Mill Site facility. The material was
staged in the sandfill areas until disposed of
in the mine stopes.10
• Ponds 1, 2, 3 and 3a, plus surrounding
areas affected by mine wastes, including
Unnamed Arroyo #1. The ponds held
stormwater and water pumped from the
NECR Site mine during dewatering. The
water was subsequently treated in the ponds
prior to discharge (under NPDES11 permit)
to the Unnamed Arroyo (Arroyo #1).
• Sediment Pad. The sediment pad was a
holding area for sediments that were
regularly removed from the ponds. The
sediment was held at the Sediment Pad until
transferred to the UNC Mill facility.
• Former Magazine Area. Storage area for
blasting materials for the mining operation.
• Vents 3 and 8 combined areas. The vents
were for the underground mining operation.
• Boneyard. Refuse and discarded equipment
from the NECR Mine were stored here.
• Non-Economic Material Storage Area. This
area was for storage of the mine overburden
and low-grade ore (unmarketable materials).
Note: The approximate 871,000 cubic yards is part of the
overall estimated 1,000,000 cubic yards of NECR mine
waste.
Principal Threat Waste
The NCP establishes an expectation that EPA
will use treatment to address the principal
threats posed by a site wherever practicable
(NCP §300.430(a)(l)(iii)(A)). In general,
principal threat wastes (PTWs) are those source
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United Nuclear Corporation Superfund Site
July 20, 2012 Page 18 of 69
materials considered to be highly toxic or highly
mobile which generally cannot be contained in a
reliable manner or would present a significant
risk to human health or the environment should
exposure occur. Conversely, non-principal
threat wastes are those source materials that
generally can be reliably contained and that
would present only a low risk in the event of
exposure. The manner in which principal threats
are addressed generally will determine whether
the statutory preference for treatment as a
principal element is satisfied. As presented in
the 2011 Non-Time-Critical Removal Action
Memorandum, all wastes containing either 200
pCi/g or more of Ra-226 and/or 500 milligrams
per kilogram (mg/kg) or more of total uranium
present a significant risk to human health should
exposure occur; therefore, based on the toxic
nature of these wastes, they are considered
PTW. The PTWs on the NECR Site are
primarily associated with Ponds 1, 2, and 3, and
the estimated volume is approximately 10,000
cubic yards (EPA, 201 lb). Under the 2011 Non-
Time-Critical Removal Action Memorandum
for the NECR Site (September 2011), the PTW
at the NECR Site would be reprocessed to
reclaim metals and radionuclides. If
reprocessing technologies are not technically
feasible, or are not available within a reasonable
What is a "PRINCIPAL THREAT"?
The NCP establishes an expectation that EPA will use treatment
to address the principal threats posed by a site wherever
practicable (NCP Section 300.430(a)(l)(iii)(A)). The "principal
threat" concept is applied to the characterization of "source
materials" at a Superfund site. A source material is material that
includes or contains hazardous substances, pollutants or
contaminants that act as a reservoir for migration of
contamination to groundwater, surface water or air, or acts as a
source for direct exposure. Contaminated groundwater generally
is not considered to be a source material; however, Non-
Aqueous Phase Liquids (NAPLs) in groundwater may be
viewed as source material. Principal threat wastes are those
source materials considered to be highly toxic or highly mobile
that generally cannot be reliably contained, or would present a
significant risk to human health or the environment should
exposure occur. The decision to treat these wastes is made on a
site-specific basis through a detailed analysis of the alternatives
using the nine remedy selection criteria. This analysis provides
a basis for making a statutory finding that the remedy employs
treatment as a principal element.
10 A stope is an open space left behind when wanted ore is
removed from an underground mine leaving behind an open
space known as a stope.
"National Pollution Discharge Elimination System, part of the
Clean Water Act.
008923
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time frame as determined by the On-scene
Coordinator handling the removal action at the
NECR Site, then the PTW will be disposed in a
facility, other than the UNC Site, that has been
determined by EPA to be acceptable under the
Off-site Rule, 40 CFR § 300.440. No PTW from
the NECR Site will be sent to the UNC Site.
This Surface Soil OU Proposed Plan for the
UNC Site addresses only whether the low level
threat mine waste from the NECR Site will be
disposed at the UNC Site as a surface soil OU
remedial action; accordingly, this Surface Soil
OU Proposed Plan is not concerned with the
PTW from the NECR Site. The waste
acceptance criteria for mine waste that will be
disposed at the UNC Site Tailings Disposal
Area are 200 pCi/g or less of Ra-226 and/or 500
mg/kg or less of uranium.
Similarity of Mine Waste found at the NECR
Site to Tailings found at the UNC Site
United Nuclear Corporation operated both the
NECR Mine and the UNC Mill. Mining
development began at the NECR Mine in 1967.
In 1977, the UNC Mill began receiving and
processing ore from the NECR Mine. Uranium
ore was processed at the UNC Mill using a
combination of crushing, grinding, and acid-
leach solvent extraction methods that produced
acidic slurry of ground rock and fluid (tailing)
that was pumped into the Tailings Disposal
Area at the UNC Site. Operations at the NECR
Mine left uranium protore (low grade ore),
waste rock, and overburden spread throughout
the NECR Site after the mine was shutdown.
The mine wastes at the NECR Site consist of
uranium-bearing waste rock that produces
uranium daughter products during decay, in
particular radium.
On January 29, 1979, the New Mexico
Environmental Improvement Division
authorized United Nuclear Corporation's use of
coarse sand tailings from the UNC Mill for
backfilling excavated mine stopes at the NECR
Mine. The tailings sands were stockpiled at
three locations prior to use as backfill in the
stopes. Rainfall runoff from the stockpile areas
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 19 of 69
was routed to four mine dewatering ponds,
where it was treated in an ion exchange circuit
prior to discharge into the nearby arroyo. Pond
sediments were periodically dredged and stored
on a muck pad located near the ponds, prior to
being transported to the UNC Mill for
processing and disposal within the Tailings
Disposal Area (NRC, 1989).
In 1988, under oversight of the NRC, United
Nuclear Corporation cleaned up the three
stockpile areas, the four ponds, and the muck
pad that were contaminated by uranium
byproduct (i.e., tailings) material12. Because
operations at the NECR Mine left non-
byproduct mine waste [uranium protore (low
grade ore), waste rock, and overburden]
throughout the NECR mine area, it was difficult
for United Nuclear Corporation to determine
whether areas were contaminated as a result of
uranium tailings material or whether the
contamination was indicative of the presence of
non-byproduct mine waste. This was
particularly true in areas where mine waste or
naturally radioactive rock outcropings masked
uranium tailings material contamination (NRC,
1989).
Identification of uranium tailings material could
not be determined by measuring the radium
content or using surface gamma surveys.
Because the milling process was over 90%
efficient at removing uranium, uranium would
be expected to be essentially absent from the
uranium tailings material while the radium
remained present. United Nuclear Corporation
used a uranium to radium ratio to distinguish
uranium tailings material from non-byproduct
mine waste (NRC, 1989). Consequently,
whenever this ratio was found in soil, United
Nuclear Corporation excavated the
contaminated soil until concentrations of radium
12 Uranium byproduct material means the tailings or wastes
produced by the extraction or concentration of uranium from
any ore processed primarily for its source material content. See
40 CFR 192.31.
008924
-------
at the bottom of the excavated area met the
cleanup level of 5 pCi/g Ra-226 above
background concentrations (NRC, 1989). United
Nuclear Corporation transported all soil
contaminated with uranium tailings material
from the NECR Site to the UNC Site for
disposal within the Tailings Disposal Area
(NRC, 1989).
Data for the primary contaminant of concern,
radium, are similar for the mine waste located at
the NECR Site and the tailings located at the
UNC Site. The data provided for the mine waste
at the NECR Site indicate that radium
concentrations range from 0.8 to 875 pCi/g for
surface soil and from 0.6 to 438 pCi/g for
subsurface soil. The average radium content of
the mine waste at the NECR Site is 30.4 pCi/g.
The data provided for the tailings at the UNC
Site indicate that radium concentrations range
from 108 to 227 pCi/g with an average radium
content of 154 pCi/g for coarse tailings and
range from 285 to 1099 pCi/g with an average
radium content of 547 pCi/g for fine-grained
tailings. As defined in the 2011 Non-Time-
Critical Removal Action Memorandum, all mine
waste that exceeds 200 pCi/g Ra-226 is
considered a principal threat waste and will not
be disposed on the UNC Site. Consequently,
Ra-226 concentrations in any mine waste that
would be taken from the NECR Site to the
Tailings Disposal Area at the UNC Site will be
lower than the Ra-226 concentrations present in
the tailings now disposed within the Tailings
Disposal Area.
The mine waste from NECR Site and tailings
from the UNC Site are similar because
contamination is derived from the same uranium
source material. Specifically, uranium tailings
sand was stockpiled and then used as backfill in
the stopes at the NECR Site. As explained
above, in 1988, the uranium tailings sand that
had been disposed on the surface of the NECR
Site was excavated under NRC oversight and
disposed within the Tailings Disposal Area at
the UNC Site. Consequently, the concentrations
of radium, the primary contaminant of concern,
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 20 of 69
in the contamination that remains at the NECR
Site, which is being addressed under the 2011
Non-Time Critical Removal Action for the
NECR Site, are within the same general range
as the concentrations of radium in the uranium
tailings material disposed at the UNC Site. In
addition, no mine waste exceeding 200 pCi/g
Ra-226 will be disposed at the UNC Site within
the Tailings Disposal Area.
SCOPE AND ROLE OF THE RESPONSE
ACTION
Because of the similarity of threat posed by the
mine waste in the areas on the NECR Site where
mine waste has been deposited and consolidated
(Consolidation Areas) and the threat posed by
the tailings in the covered pits and landfills that
make up the UNC Site Tailings Disposal Area,
as well as the relative proximity of these
facilities (less than 1 mile; Figure 1), EPA
proposes to use its authority under CERCLA
Section 104(d)(4) to temporarily combine the
NECR Site Consolidation Areas and the UNC
Site Tailings Disposal Area for the purpose of
remediation. The combination of these two
areas, the NECR Site Consolidation Areas and
the UNC Site Tailings Disposal Area, is
temporary and for mine waste disposal purposes
only.
The combination of the NECR Site
Consolidation Areas and the UNC Site Tailings
Disposal Area would be temporary, because
once all the mine waste from the NECR Site
Consolidation Areas has been transferred to the
UNC Site Tailings Disposal Area, these
facilities (i.e., the Consolidation Areas and the
Tailings Disposal Area) will no longer be
combined within the meaning of Section
104(d)(4). Also, at no time will any of the
NECR Site, including the Consolidation Areas
be part of the UNC Site for NPL purposes. The
UNC Site will continue to be the NPL site, and
it will not include the NECR Site. For example,
the NECR mine and surrounding area that make
up the NECR Site will not be considered when
construction completion, close-out, and delisting
of the UNC Site from the NPL are considered.
008925
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In accordance with EPA's 2011 Non-Time-
Critical Removal Action Memorandum, the
NECR Site removal action will be undertaken
pursuant to Section 104(a)(1) of CERCLA, 42
U.S.C. § 9604(a)(1), and Section 300.415 of the
NCP, 40 CFR § 300.415 to mitigate threats to
human health and the environment posed by the
presence of hazardous substances at the NECR
Site. The UNC Site remedial action will be
undertaken pursuant to Section 104(a)(1) of
CERCLA, 42 U.S.C. § 9604(a)(1), with the
remedy selected pursuant to the remedy
selection process described in the NCP at 40
CFR § 300.430. After EPA has evaluated
comments submitted regarding this Surface Soil
OU Proposed Plan, EPA's remedy selection will
be documented in the Surface Soil OU Record
of Decision (ROD). EPA's response to public
comments will be documented in a
Responsiveness Summary that is part of the
ROD.
This proposed remedial action, referred to as the
surface soil OU proposed remedial action, will
be taken as an intermediate step prior to final
remedial action for the surface soil OU at the
UNC Site. From 1992 to 1995, surface
reclamation actions for the Tailings Disposal
Area were completed under the oversight of the
NRC and resulted in the consolidation and
capping of the uranium byproduct material (i.e.,
tailings). Because of the similarity of the threat
posed by the mine waste in the areas on the
NECR Site where mine waste has been
deposited and consolidated (Consolidation
Areas) and the threat posed by the tailings
located in the UNC Site Tailings Disposal Area,
it is appropriate to manage these wastes from
the NECR Site and UNC Site together. The
mine waste from the NECR Site can be
collocated, disposed, and managed together with
the tailings in the UNC Site Tailings Disposal
Area to address potential health risks.
Collocation of the NECR Site mine wastes with
the UNC Site tailings will be consistent with
and supplemental to the Tailings Disposal Area
reclamation actions. The NECR Site mine waste
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 21 of 69
will be consolidated and disposed on top of the
tailings within the Tailing Disposal Area
followed by capping of the mine waste and
tailings. Once the NECR Site mine waste has
been disposed in the UNC Site Tailings
Disposal Area and all the mine waste and
tailings are capped, final reclamations actions,
including backfilling of the evaporation ponds,
capping of the evaporation pond area, and
construction of the final drainage swales at the
Tailings Disposal Area, will be completed.
This surface soil OU remedial action at the
UNC Site will be consistent with and
supplemental to actions that will be necessary
for NPL site completion and for deletion of the
site from the NPL under CERCLA. This surface
soil OU remedial action will address disposal of
approximately 1,000,000 cubic yards of mine
waste. This includes approximately 871,000
cubic yards from the removal action described
in the 2011 Non-Time-Critical Removal Action
Memorandum for the NECR Site, 109,800 cubic
yards from a removal action at the NECR Site
that predates the 2011 Non-Time-Critical
Removal Action Memorandum for the NECR
Site, and an estimated 30,000 cubic yards to be
excavated as part of a separate time-critical
removal action at the NECR Site. The estimated
1,000,000 cubic yards of mine waste from the
NECR Site is approximately 1.35 million tons13.
It is estimated that approximately 3.5 million
tons of tailings have been disposed within the
Tailings Disposal Area at the UNC Site. The
1.35 million tons of mine waste from the NECR
Site represents an approximate volume increase
within the Tailings Disposal Area of 38%.
This surface soil OU remedial action does not
include approximately 10,000 cubic yards of
PTW addressed in the 2011 Non-Time-Critical
13 The estimated volume of mine waste at the NECR site being
considered for disposal at the UNC Site within the Tailings
Disposal Area is approximately 1 million cubic yards. A
conversion factor of 1.35 cubic yards per tons was used to
convert the volume from cubic yards to tons.
008926
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Removal Action Memorandum for the NECR
Site. The waste acceptance criteria for mine
waste that will be disposed at the UNC Site
Tailings Disposal Area are 200 pCi/g or less of
Ra-226 and/or 500 mg/kg or less of uranium.
This surface soil OU remedial action at the
UNC Site is independent of the ground water
remedial actions that are undertaken by United
Nuclear Corporation under the EPA's 1988
ROD for the UNC Site. Ground water
monitoring and extraction wells are located at
the boundary and downgradient of the Tailings
Disposal Area. Ground water monitoring and
remediation of the contaminant plumes is
ongoing and will continue under the 1988 ROD
as a separate remedial action. Ground water is
not a component of this Surface Soil OU
Proposed Plan, which addresses only the
proposed disposal of the NECR Site low level
threat mine waste at the UNC Site. Mine waste
disposal within the Tailings Disposal Area is not
expected to interfere or affect the current ground
water remediation efforts. Mine waste disposal
will be designed and constructed to provide for
continued protection against contaminant
migration into the ground water (see Summary
of Remedial Alternatives section) in support of
ongoing ground water remediation efforts.
The Surface Soil OU preferred alternative
proposes the permanent disposal of mine waste
from the NECR Site Consolidation Areas within
the Tailings Disposal Area at the UNC Site.
Accordingly, EPA will issue a final Record of
Decision consistent with CERCLA and the NCP
for all portions of the UNC Site, including those
areas being addressed by the NRC before the
UNC Site is deleted from the NPL. All mine
waste from the NECR Consolidation Areas and
the tailings located within the Tailings Disposal
Area at the UNC Site, will be contained on the
UNC Site for perpetuity. It is expected that there
would be a transfer of the UNC Site to the
Department of Energy's (DOE's) Long-Term
Surveillance and Maintenance Program under
DOE's Office of Legacy Management. Under
this DOE program, the UNC Site would be
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 22 of 69
maintained and managed under the DOE to
provide for continued containment and
protectiveness.
NRC License Amendment, Step Two: In that
the UNC Site is under EPA and NRC
jurisdiction and as outlined in the 2011 Non-
Time Critical Removal Action Memorandum,
disposal of mine waste from the NECR Site
within the Tailings Disposal Area at the UNC
Site is contingent on two actions.
Step one: EPA issues an appropriate decision
document consistent with the National Oil and
Hazardous Substances Pollution Contingency
Plan (40 CFR Part 300) (NCP) process,
including assessment of State and community
acceptance, where EPA selects disposal of mine
waste from the NECR Site within the Tailings
Disposal Area of the UNC Site as a surface soil
OU remedy for the UNC Site. This Surface Soil
OU Proposed Plan begins EPA's process to
fulfill step one.
Step two: Disposal of mine waste from the
NECR Site within the Tailings Disposal Area at
the UNC Site will require acceptance by the
NRC and is contingent on an amendment of
United Nuclear Corporation's NRC license to
allow for disposal. The license amendment
process will begin when United Nuclear
Corporation submits for NRC review and
evaluation a request for an amendment of its
NRC license to accommodate disposal of mine
waste from the NECR Site within the Tailings
Disposal Area at the UNC Site. NRC's
agreement to amend the United Nuclear
Corporation's license to allow this disposal will
be necessary to fulfill step two.
SUMMARY OF SITE RISKS
At a Superfund site, where EPA is responding to
contamination, the NCP calls for a site-specific
baseline human health risk assessment (HHRA)
to be conducted, as appropriate, as part of the
remedial investigation (Section 300.430(d)(1)).
The NCP states that the baseline risk assessment
should characterize the current and potential
008927
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threats to human health and the environment
that may be posed by contaminants (Section
300.430(d)(4)). The results of the baseline
human health risk assessment will help establish
acceptable exposure levels for use in developing
What is Risk and How is it Calculated?
A CERCLA human health risk assessment estimates the "baseline
risk." This is an estimate of the likelihood of health problems
occurring if no cleanup action were taken at a site. To estimate the
baseline risk at a CERCLA site, EPA identifies a four-step
process:
Step 1: Identify Chemicals of Concern
Step 2: Estimate Exposure
Step 3: Assess Potential Health Effects
Step 4: Characterize Site Risk
In Step 1, the risk assessor compiles all the chemical data for a
site to identify what chemicals were detected in each medium (i.e.
soil and groundwater). Chemicals that are detected frequently at
high concentrations, or are considered highly toxic, are
considered "chemicals of concern" and are evaluated in the risk
assessment.
In Step 2, the risk assessor considers the different ways that
people might be exposed to the contaminants identified in Step 1,
the concentrations that people might be exposed to, and the
potential frequency and duration of exposure. Using this
information, the risk assessor calculates a "reasonable maximum
exposure" (RME) scenario, which portrays the highest level of
human exposure that could reasonably be expected to occur.
In Step 3, the risk assessor compiles toxicity information on each
chemical, including numeric values for assessing cancer and
noncancer adverse health affects. The EPA identifies two types of
risk: cancer risk and noncancer risk. The likelihood of any kind of
cancer resulting from a CERCLA site is generally expressed as an
upper bound probability; for example, a " 1 in 10,000 chance." In
other words, for every 10,000 people that could be exposed, one
extra cancer may occur as a result of exposure to site
contaminants. An extra cancer case means that one more person
could get cancer than would normally be expected to from all
other causes. This extra cancer risk due to the site contaminants is
also referred to in this proposed plan as an excess lifetime cancer
risk. For non-cancer health effects, the risk assessor calculates a
"hazard index." The key concept here is that a "threshold level"
measured usually as a hazard index of less than 1) exists below
which noncancer health effects are no longer predicted.
In Step 4, the risk assessor uses the exposure information from
Step 2 and toxicity information from Step 3 to calculate potential
cancer and noncancer health risks. The results are compared to
EPA acceptable levels of risk to determine whether site risks are
great enough to potentially cause health problems for populations
at or near the CERCLA site.
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 23 of 69
remedial alternatives.
Since the action contemplated in this Surface
Soil OU Proposed Plan is a response to
contamination that was found at the NECR Site,
the pertinent baseline HHRA is the one that was
prepared for the NECR Site. As part of the
NECR Site evaluation and under EPA
supervision, United Nuclear Corporation
performed a baseline HHRA, along with a
conceptual site model, and a screening level
human health risk assessment. The results of
the baseline HHRA are specific to the NECR
Site, are summarized here, and can be found in
more detail in the RSE Report, the EE/CA, and
the 2011 Non-Time-Critical Removal Action
Memorandum for the NECR Site.
The baseline HHRA for the NECR Site focused
on the potential for human health effects from
exposure to contaminants at the NECR Site
through external radiation from soil and
sediment; incidental ingestion, direct contact,
and inhalation of soil and sediment; and
ingestion of homegrown produce and locally-
raised meat and eggs. The populations
characterized for the risk assessment included
current and future off-site residents, current and
future on-site maintenance worker, future on-
site resident, and future livestock grazer.
The baseline HHRA for the NECR Site
identified unacceptable excess lifetime cancer
risk associated with Ra-226 and unacceptable
excess non-cancer risk associated with uranium.
Ra-226 and uranium are identified as the
contaminants of concern (COCs). The excess
lifetime cancer risk associated with Ra-226 was
estimated at 1 xlO"2, which means that one
person out of 100 persons could be expected to
develop cancer, attributable to the NECR Site,
over a lifetime of exposure. The excess non-
cancer risk associated with uranium was
estimated as high as 24. Since 24 exceeds 1,
there is a potential for adverse health effects
from potential exposure.
008928
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The 2011 Non-Time-Critical Removal Action
Memorandum for the NECR Site set the NECR
Site cleanup level for Ra-226 as 2.24 pCi/g and
the NECR cleanup level for uranium as 230
mg/kg.
On the NECR Site, mine waste has been
excavated and deposited in certain areas where
it is consolidated with mine waste from other
parts of the NECR Site. These areas are referred
to as the Consolidation Areas. Because of the
similarity between the threat posed by the mine
waste now located in the Consolidation Areas
on the NECR Site and the threat posed by the
tailings located in the UNC Site Tailings
Disposal Area, these mine wastes can be
collocated, disposed, and managed together to
address potential health risks. This Surface Soil
OU Proposed Plan proposes collocating and
disposing of the mine waste from the NECR
Consolidation Areas with the tailings already on
the UNC Site in the Tailings Disposal Area.
As described previously, EPA reviewed
documents related to the construction of the
Tailings Disposal Area, in order to determine
the load effect that the additional mine waste
from the NECR Site would have on the tailings
already disposed in the Tailings Disposal Area
as well as documentation related to current
ground water conditions (see Site Background.
Previous Actions. History of EPA Involvement
at the NECR Site and Site Characteristics. UNC
Site. Ground Water). Based on conservative
evaluations of the tailings profiles and model
sensitivity analyses (Dwyer, 2011) as well as
review of disposal cell settlement data (UNC,
1993; Smith, 1996b), the added mine waste is
not expected to result in the release of
additional tailings liquid into the ground water
or surrounding soil, is not expected to interfere
or affect the current tailings or ground water
remediation efforts that are currently ongoing,
and is not expected to affect the stability of the
tailings disposal cells. Current ground water
elevation data show that the tailings are not in
direct contact with the water table in the
Southwest Alluvium, Zone 3, or Zone 1.
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superjund Site
July 20, 2012 Page 24 of 69
Based on the RSE and the EE/CA, EPA
determined that actual or threatened releases
from the NECR Site, if not addressed by
implementing the response action outlined in the
2011 Non-Time-Critical Removal Action
Memorandum may continue to present an
imminent and substantial endangerment to
public health and the environment. This
What are the "Contaminants of Concern"?
The EPA and NMED have identified contaminants in soil that
pose the greatest potential risk to human health and the
environment. Adverse affects described below are dependent on
chemical concentration and exposure duration.
Radionuclides: As uranium breaks down over time, it turns into
radium. Radium is a radioactive substance that occurs in two
forms, which are also called isotopes, Ra-226 and Ra-228. As
radium breaks down over time, it releases alpha, beta and
gamma radiation. Radium may be found in air, water and soil
and plants may absorb radium in the soil. Breathing in high
levels of radium can cause adverse effects to the blood (anemia)
and eyes (cataracts). Radium releases alpha radiation, which can
have toxic health effects on the lungs. Ra-226 also has been
shown to affect the teeth, causing an increase in broken teeth and
cavities. Exposure to high levels of radium results in an
increased incidence of bone, liver, and breast cancer. The
U.S.EPA and the National Academy of Sciences, Committee on
Biological Effects of Ionizing Radiation, have stated that radium
is a known human carcinogen that can cause cancer (AT SDR,
1999). Inhalation of radium contaminated particulates is of
particular concern. Radium emits alpha radiation, which, when
inhaled, becomes a source of ionizing radiation in the lung and
throat, possibly leading to toxic effects.
Radon: Radon is a naturally occurring gas that comes from
radioactive uranium in soil and rocks. Radioactive materials like
uranium break down and change over time. Uranium
disintegrates into radium, and after more time, radium
disintegrates into radon. Since radon is a gas, it moves around
easily through soil and flows from the ground into the
atmosphere or into homes, schools, and other buildings. Radon
gas is odorless, tasteless and transparent, but it can cause health
problems. Radon releases alpha particles as it continues to break
down. Alpha particles can penetrate lung tissue and cause
damage. Breathing in too many alpha particles can cause serious
health consequences, including lung cancer. The EPA,
Department of Health and Human Resources, and International
Agency for Research on Cancer consider radon to be a human
carcinogen (ATSDR, 2008). In colder climates where people
heat their homes, the warmer air rises. This creates higher
pressure upstairs and lowers pressure downstairs. This pressure
difference creates a low power vacuum that can suck up radon
from the soil underneath the house. This is a major reason why
there are elevated levels of radon in some buildings.
008929
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determination led to the issuance of the 2011
Non-Time-Critical Removal Action
Memorandum (EPA, 201 lb) for the NECR Site,
which calls for disposal of the NECR mine
waste at the UNC Site contingent upon EPA's
issuance of an appropriate decision document by
EPA Region 6 consistent with the NCP. EPA
has determined that the Preferred Alternative
identified in this Surface Soil OU Proposed
Plan, or some other remedial action alternative
that addresses the contamination assessed in the
baseline HHRA, is necessary to protect public
health or welfare or the environment from actual
or threatened releases of hazardous substances
into the environment.
REMEDIAL ACTION OBJECTIVES AND
PRELIMINARY REMEDIATION GOALS
This section of the Surface Soil OU Proposed
Plan provides the basis for evaluating the
remedial alternatives presented in the section,
Summary of Remedial Alternatives. When
determining which remedial alternative to
select at a Superfund site, the NCP requires that
EPA establish remedial action objectives.
Remedial action objectives are to specify
contaminants of concern, media (e.g., soil,
water, air), potential exposure pathways, and
remediation goals.
Remediation goals consist of medium-specific
chemical concentrations that are protective of
human health and the environment and serve as
goals for the remedial action. To protect human
health, EPA has set the acceptable risk range
for carcinogens at Superfund Sites from 1 in
10,000 to 1 in 1,000,000 (expressed as 1 x 10"4
to 1 x 10"6). A risk of 1 in 1,000,000 (1 x 10"6)
means that one person out of one million
people could be expected to develop cancer as
a result of a lifetime exposure to the site
contaminants. Where the aggregate risk from
COCs based on existing applicable or relevant
and appropriate requirements (ARARs)
exceeds lxl0"4, or where remediation goals are
not determined by ARARs, EPA uses the
lxl 0"6 as a point of departure for establishing
preliminary remediation goals. This means that
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 25 of 69
a cumulative risk level of lxl0"6 is used as the
starting point (or initial "protectiveness" goal)
for determining the most appropriate risk level
that alternatives should be designed to attain.
Factors related to exposure, uncertainty and
technical limitations may justify modification of
initial cleanup levels that are based on the 1x10"
6 risk level.
The remediation goals described in this Surface
Soil OU Proposed Plan are specific to the
disposal and containment of mine waste and
tailings within the Tailings Disposal Area.
Under Clean Air Act rulemaking establishing
National Emission Standards for Hazardous Air
Pollutants (NESHAPs) for NRC licensees,
Department of Energy facilities, and many other
What are Remediation Goals?
Remediation Goals for Carcinogens - To protect human
health, EPA has set the acceptable risk range for carcinogens at
Superfund Sites from 1 in 10,000 to 1 in 1,000,000 (expressed as
1 x 10"4 to 1 x 10~6). A carcinogen is a substance that causes
cancer or is believed to cause cancer based on scientific studies.
A risk of 1 in 1,000,000 (1 x 10"6) means that one person out of
one million people could be expected to develop cancer as a
result of a lifetime exposure to the site contaminants. Where the
aggregate risk from Contaminants of Concern (COCs) based on
existing Applicable or Relevant and Appropriate Requirements
(ARARs) exceeds 1 x 10~4, or where remediation goals are not
determined by ARARs, EPA uses the 1 x 10"6 as a point of
departure for establishing preliminary remediation goals. This
means that accumulative risk level of 1 x 10~6 is used as the
starting point (or initial "protectiveness" goal) for determining the
most appropriate risk level cleanup alternatives should be
designed to attain. Factors related to exposure, uncertainty and
technical limitations may justify modification of preliminary
remediation goals levels that are based on the 1 x 10"6 risk level.
Remediation Goals for Toxic Non-Carcinogens - For toxic
COCs that are not known to cause cancer, the toxicity assessment
is based on the use of reference doses (RfDs) whenever available.
A reference dose is the concentration of a chemical known to
cause health problems. The estimated potential site-related intake
of a compound is compared to the RfDs in the form of a ratio,
referred to as the hazard quotient (HQ). If the F1Q is less than one,
no adverse health effects are expected from potential exposure.
When environmental contamination involves exposure to a
variety or mixture of compounds, a hazard index (HI) is used to
assess the potential adverse effects for this mixture of
compounds. The HI represents a sum of the hazard quotients
calculated for each individual compound. HI values that approach
or exceed one generally represent an unacceptable health risk that
requires remediation.
008930
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kinds of sites, EPA determined that radon
emissions of 20 picocuries per square meter per
second (pCi/m2s) results in a maximum
individual risk of 1.8 x 10"4 and concluded that a
risk level of "1.8 x 10"4 is essentially equivalent
to the presumptively safe level of 1 x 10"4." [54
Fed. Reg. at 51673 (December 15, 1989)]. The
remediation goal for radon represents a 1 x 10"4
risk and is set in accordance with the established
Clean Air Act NESHAP which is also consistent
with Uranium Mill Tailings Radiation Control
Act requirements.
The remediation goals described in this Surface
Soil OU Proposed Plan are preliminary
remediation goals because the actual
remediation goals will be selected in EPA's
Surface Soil OU Record of Decision.
Remedial Action Objectives. The RAOs for
this Surface Soil OU proposed action are:
• Prevent exposure to current and future
human and ecological receptors from
external radiation, ingestion, dermal contact,
and inhalation (i.e., inhalation of associated
gas or dust) of soil, mine waste, and tailings
contained within the Tailings Disposal Area
containing concentrations of radionuclides
and their daughter products that exceed
preliminary remediation goals.
• Prevent migration [on-site and off-site into
soil, sediment, ground water, air (as gas or
dust), and surface water] of soil, mine waste,
and tailings located within the Tailings
Disposal Area containing concentrations of
radionuclides and their daughter products
such that exposure to current and future
human and ecological receptors from
external radiation, ingestion, dermal contact,
and inhalation (i.e., inhalation of associated
gas or dust) of soil, mine waste, and tailings
does not exceed preliminary remediation
goals.
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 26 of 69
• Prevent the migration of concentrations of
contaminants located in the soil, mine waste,
and tailings contained within the Tailings
Disposal Area to ground water where the
migration of those contaminants would
result in ground water concentrations that
exceed remediation goals established in
EPA's 1988 ROD for the Ground Water
Operable Unit (including any amendment),
and, through this action, prevent human and
ecological receptors from being exposed to
ground water with concentrations of
contaminants that exceed remediation goals
established in the 1988 ROD, including any
amendment.
These RAOs pertain to this surface soil OU
proposed action which includes the construction
(or reconstruction) of parts of the Tailings
Disposal Area on the UNC Site to contain the
mine waste from the NECR Site.
Preliminary Remediation Goals:
• Radionuclides and their daughter products in
soil, mine waste, and tailings contained
within the Tailings Disposal Area will not
release radon-222 emissions from residual
radioactive material to the atmosphere in
exceedance of an average14 release rate of
20 picocuries per square meter per second
(pCi/m2s)15 [40 CFR §§ 192.02(b)(1) and
192.32(b)(1)(h)],
14 This average shall apply to the entire surface of each disposal
area over periods of at least one year. Radon will come from
both uranium byproduct materials and from materials used to
cover the uranium byproduct materials. Radon emissions from
materials used as a cover should be estimated as part of
developing a closure plan for each site. The standard, however,
applies only to emissions from uranium byproduct materials to
the atmosphere [ 192,32(b)( 1 )(ii)].
15 Under Clean Air Act rulemaking establishing NESHAPs for
NRC licensees, Department of Energy facilities, and many other
kinds of sites, EPA concluded that a risk level of "1.8 x 10"4 is
essentially equivalent to the presumptively safe level of 1 x 10"
4." 54 Fed. Reg. at 51673 (December 15, 1989).
008931
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• Radionuclides and their daughter products in
soil, mine waste, and tailings contained
within the Tailings Disposal Area will not
release radon-222 emissions from residual
radioactive material to the atmosphere that
will increase the annual average
concentration of radon -222 in air at or
above any location outside the disposal site
by more than one-half picocurie per liter [40
CFR § 192.02(b)(2)],
• Migration of contaminants from the Tailings
Disposal Area shall not result in ground
water concentrations that exceed
remediation goals established in EPA's 1988
ROD for the Ground Water Operable Unit,
including any amendment.
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 27 of 69
respect to migration and all exposure routes
including external radiation, ingestion, dermal
contact, and inhalation.
The parts of the Tailings Disposal Area that are
to contain the mine waste from the NECR Site
will be designed and constructed to meet the
RAO's (including the Preliminary Remediation
Goals) and to meet ARARs found in 40 CFR
Part 192, Subparts A and D; 40 CFR Part 264
Subparts G and K; and 40 CFR Part 61 Subpart
H, Subpart Q, and Subpart T (Table 1). The
final list of UNC Site ARARs will be presented
in the Final Surface Soil OU ROD.
Furthermore, the parts of the Tailings Disposal
Area where the mine waste from the NECR Site
is disposed will be closed in such a manner that
they will control, minimize or eliminate, to the
extent necessary to protect human health and the
environment, post-closure escape of hazardous
waste, hazardous constituents, leachate,
contaminated run-off, or hazardous waste
decomposition products to the ground or surface
water or to the atmosphere and be effective for
one thousand years, to the extent reasonably
achievable, and, in any case, for at least 200
years. [40 CFR §§ 192.02(a), 192.32(b)(1),
264.111(a), 264.111(b), 264.228(b)(1),
264.228(b)(3), and 264.228(b)(4)],
SUMMARY OF REMEDIAL
ALTERNATIVES
As described previously, EPA performed
additional evaluations on 11 alternate disposal
locations that could potentially be used for
disposal of the NECR Site mine waste as well as
various locations, other than the Tailings
Disposal Area, within the boundary of the UNC
Site (see Site Background. Previous Actions.
History of EPA Involvement at the NECR Site).
After consideration of the administrative, legal
and cost challenges presented by each of the 11
alternate locations reviewed, the UNC Site was
identified as the most suitable (EPA, 201 la). In
addition, as explained in the EE/CA and
summarized in the 2011 Non-Time-Critical
Removal Action Memorandum for the NECR
Preliminary Remediation Goals
Contaminant
of Concern
Preliminary Remediation Goals
Radon-220
and Radon
222
Average1 release rate of 20
picocuries per square meter per
second (pCi/m2s)
Radon-220
and Radon
222
annual average concentration in air
at or above any location outside the
disposal site does not increase by
more than one-half picocurie per
liter
'This average shall apply to the entire surface of each disposal area
over periods of at least one year, but short compared to 100 years.
Radon will come from both uranium byproduct materials and from
covering materials. Radon emissions from covering materials should
be estimated as part of developing a closure plan for each site. The
standard, however, applies only to emissions from uranium byproduct
materials to the atmosphere [192.32(b)(l)(ii)l.
Although the preliminary remediation goals in
the preceding bulleted items are expressed in
terms of concentrations of contaminants
in the atmosphere or in terms of the
concentrations of migrating contaminants from
the Tailings Disposal Area that could result in
ground water contamination that exceeds the
remediation goals in the 1988 ROD, including
any amendment, the concentrations that protect
the ambient air in combination with the UNC
Site use restrictions and the installation of the
cap for containment will be protective with
008932
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Site (EPA, 201 lb), on-site disposal of the
NECR Site mine waste at the NECR Site was
rejected by the Navajo Nation and the
community16. The two areas on the UNC Site
identified as potentially large enough to
accommodate the volume of mine waste were
determined to be unacceptable. One location
considered would not be acceptable as it would
require the plugging and abandonment of all
wells associated with the ongoing ground water
remedial action while the second location was
determined to be too small to accommodate the
volume of the NECR Site mine waste that must
be disposed there (EPA, 2010).
As described previously, EPA reviewed
documents related to the construction of the
Tailings Disposal Area, in order to determine
the load effect that the additional tailings from
the NECR Site would have on the tailings
already disposed in the Tailings Disposal Area
as well as documentation related to current
ground water conditions (see Site Background.
Previous Actions. History of EPA Involvement
at the NECR Site and Site Characteristics. UNC
Site. Ground Water). Based on conservative
evaluations of the tailings profiles and model
sensitivity analyses (Dwyer, 2011) as well as
review of disposal cell settlement data (UNC,
1993; Smith 1996b), the added mine waste is
not expected to result in the release of additional
tailings liquid into the ground water or
surrounding soil, is not expected to interfere or
affect the current mine waste or ground water
remediation efforts that are currently ongoing,
and is not expected to affect the stability of the
tailings disposal cells. Current ground water
elevation data show that the tailings are not in
direct contact with the water table for the
Southwest Alluvium, Zone 3, or Zone 1.
16 In EPA's Action Memorandum for the Non-Time Critical
Removal Action at the NECR Site (September 2011), EPA
rejected any disposal on the NECR Site because of the
objections of the Navajo Nation and the local community.
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 28 of 69
Given the limited availability of land within the
UNC Site boundary, the only location for NECR
mine waste disposal at the UNC Site, would be
within the UNC Tailings Disposal Area. Based
on conservative evaluations of the tailings
profiles and model sensitivity analyses as well
as review of disposal cell settlement data,
adding the NECR mine waste to the Tailings
Disposal Area is not expected to result in the
release of additional tailings liquid into the
ground water or into the surrounding soil.
Furthermore, adding the NECR mine waste to
the Tailings Disposal Area is not expected to
interfere or affect the ongoing mine waste or
ground water remediation efforts at the UNC
Site, nor is it expected to affect the stability of
the tailings disposal cells. EPA recognizes the
limitations of the simulations and model results.
During remedial design, additional data will be
collected and evaluated to further refine,
support, and verify these conclusions.
This surface soil OU remedial action at the
UNC Site is independent of the ground water
remedial actions that are undertaken by United
Nuclear Corporation under the EPA's 1988
ROD for the UNC Site. Ground water is not a
component of this Surface Soil OU Proposed
Plan, which addresses only the proposed
disposal of the NECR Site low level threat mine
waste at the UNC Site. Ground water
monitoring and extraction wells are located at
the boundary and downgradient of the Tailings
Disposal Area. Ground water monitoring and
remediation of the contaminant plumes is
ongoing and will continue under the 1988 ROD
as a separate remedial action. Mine waste
disposal within the Tailings Disposal Area is not
expected to interfere or affect the current ground
water remediation efforts. Mine waste disposal
will be designed and constructed to provide for
continued protection against contaminant
migration into the ground water (see Summary
of Remedial Alternatives section) in support of
ongoing ground water remediation efforts.
A total of two remedial alternatives are being
considered for the UNC Site with regards to
008933
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disposal of the mine waste from the NECR Site
in the Tailings Disposal Area. These two
alternatives are evaluated below in this Surface
Soil OU Proposed Plan against the nine NCP
criteria found at 40 CFR § 300.430(e)(9)(iii).
The Preferred Alternative for the UNC Site is
Alternative 2: On-site Disposal at the UNC Site
within the Tailings Disposal Area.
Alternative 1: No Action Alternative
Regulations governing the Superfund program
require that the "no action" alternative be
evaluated to establish a baseline for comparison.
Under the no action alternative, the UNC Site
Tailings Disposal Area would not be used as the
disposal area for the NECR Site mine waste.
This would have no impact on the UNC Site in
that the UNC Site would remain as it is now.
Alternative 2: On-site Disposal at the UNC
Site within the Tailings Disposal Area
Alternative 2 includes the transportation,
consolidation, and disposal of NECR Site mine
waste at the UNC Site within the Tailings
Disposal Area.
The implementation of Alternative 2 will
include the following elements:
• Site Controls and Security: During response
activities access will be restricted by
construction of a temporary fence. Domestic
livestock or unauthorized persons would not
be allowed to enter.
• Site preparation activities include an
underground utility survey to identify and/or
verify the location of subsurface utilities in
areas scheduled for consolidation and
disposal; identification of heavy equipment
routes; and temporary stockpiling activities.
These temporary stockpiling activities refer
to an area where mine waste will be placed
in preparation for placement within the
Tailings Disposal Area. A land survey will
be completed to delineate the parts of the
Tailings Disposal Area that will be used for
mine waste disposal. Site construction
activities necessary to prepare the site for
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 29 of 69
mine waste placement will be completed.
Existing structures such as culverts, catch
basins, foundations, and vaults will be
decontaminated where practical,
disassembled for future use, demolished for
removal, or included within the disposal
area.
• Trained and experienced labor will be used
to transport and manage the mine waste.
Special certifications and health and safety
training requirements to comply with
Occupational Safety and Health
Administration, radiation, and hazardous
material handling requirements will be
maintained throughout the project.
Graduates trained and certified under the US
EPA Superfund Jobs Training Initiative will
also be eligible for hiring for identified
positions.
• Transportation of all mine waste will be
transported in such a manner to mitigate the
production of dust, including the use of
covers and/or dust suppression actions. A
transportation plan will be used to identify
the routes of travel, times of operation, and
traffic rules. Emergency spill containment
and cleanup contingencies would also be
included in the transportation plan to address
mine waste spills.
• Temporary on-site facilities for proj ect
management and project controls will be
mobilized to the UNC Site for the duration
of the project. Temporary facilities will be
constructed for the decontamination of
personnel and equipment and the storage of
decontamination equipment (e.g., tools,
salvageable equipment, passenger vehicles
and heavy equipment), and mine waste.
• Natural and cultural resources will be
surveyed by a Navajo Nation archeologist
and the State and Tribal Historic
Preservation Officer will be consulted in
accordance with the National Historic
Preservation Act. Local residents will be
consulted as part of this process.
• Perimeter air monitoring stations will be
positioned and operated to monitor
008934
-------
emissions during site preparation,
construction, stockpiling, loading of bulk-
carriers, stockpile management,
consolidation, cover construction and
restoration. Dust suppression controls will
be implemented to maintain a safe working
environment and to protect human health
and the environment.
• Stormwater and Erosion Control: Disturbed
areas will be graded to reduce scouring and
erosion potential using gentle slopes,
terraces, earthen ridges and catch drains
(swales) as necessary. These controls will
also be used to minimize the potential for
ponded water, reduce the risk of percolation
from ponded water, and divert water away
from open disposal locations, construction
zones, and exposed mine waste. The
drainage patterns in the disturbed areas will
be integrated with the existing topography
and drainage patterns to the extent possible.
During construction activities, stormwater
controls may include stormwater control
channels (header), weirs, spillways, catch
basins, check dams, and sediment basins.
These controls will be implemented to
maintain a safe working environment, to
protect human health and the environment,
mitigate off-site migration of mine waste,
and protect response construction actions.
• Waste Volume: Approximately 871,000
cubic yards from the removal action
described in the 2011 Non-Time-Critical
Removal Action Memorandum for the
NECR Site, 109,800 cubic yards from a
removal action at the NECR Site that
predates the 2011 Non-Time-Critical
Removal Action Memorandum for the
NECR Site, and an estimated 30,000 cubic
yards to be excavated as part of a separate
time-critical removal action at the NECR
Site will be interred at the Tailings Disposal
Area and capped. Although the additional
109,800 and 30,000 cubic yards volume was
not included in the EE/CA, the additional
volume and associated cost are minimal
compared to the overall volume and cost
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 30 of 69
evaluated. In addition the added expense is
within the EE/CA's margin of error. Based
on this, the additional volume and cost are
considered included and addressed under
this alternative. The waste acceptance
criteria for mine waste that will be disposed
at the UNC Site Tailings Disposal Area are
200 pCi/g or less of Ra-226 and/or 500
mg/kg or less of uranium.
• Team Coordination: The UNC Site is under
EPA and NRC jurisdiction. As outlined in
the 2011 Non-Time Critical Removal Action
Memorandum, disposal of mine waste from
the NECR Site within the Tailings Disposal
Area at the UNC Site is contingent on two
actions being taken. This Surface Soil OU
Proposed Plan begins EPA's process to
fulfill step one: issuance of an appropriate
decision document consistent with the NCP.
Step two involves United Nuclear
Corporation's submittal of a request for an
amendment to its NRC license. The
amendment, if granted by NRC, after its
review and evaluation, would accommodate
disposal of mine waste from the NECR Site
within the Tailings Disposal Area at the
UNC Site. NRC's agreement to amend the
United Nuclear Corporation's license to
allow this disposal will be necessary to
fulfill step two as described in the 2011
Non-Time-Critical Removal Action
Memorandum. Once all required actions are
completed per the terms of the NRC license,
it is expected that there would be a transfer
of the UNC Site to the DOE's Long-Term
Surveillance and Maintenance Program
under DOE's Office of Legacy
Management. Under this DOE program, the
UNC Site would be maintained and
managed under the DOE to provide for
continued containment and protectiveness.
Close coordination with the NRC, DOE,
EPA Region 9, NNEPA, the community,
and the State of New Mexico will be
required to create an acceptable design that
incorporates the NECR mine waste into the
existing UNC Tailings Disposal Area,
008935
-------
complies with the NRC/DOE permit
requirements, and complies with EPA and
State regulations.
• Cap Design Criteria: Although the final
design may vary, the major elements of the
structure are not expected to be significantly
different than those presented here. The cap
design will be based on comprehensive
planning, site-specific risk analysis, and
ARARs. Cap design and cost estimates for
Alternative 2 are based on the following
elements:
o cap longevity designed for a minimum
of 200 years with minimal
maintenance and for effectiveness up
to one thousand years, to the extent
reasonably achievable [40 CFR §§
192.02(a), 192.32(b)(l)(i), and
264.111(a)];
o a sufficient clean (uncontaminated)
soil layer to provide assurance that
releases in the form of Radon-220 and
-222 will not exceed an average
release rate of 20 picocuries per meter
squared per second [40 CFR §§
192.02(b)(1) and 192.32(b)(1)(h)], and
will not increase the annual average
concentration of radon-220 and -222 in
air at or above any location outside the
disposal site by more than one-half
picocurie per liter [40 CFR §
192.02(b)(2)];
o cap construction to protect the mine
waste, reduce the potential for leachate
development, and prevent
contaminated runoff by limiting
infiltration of precipitation and by
providing erosion protection and
durability [40 CFR §§ 192.32(b)(1),
264.111(a), 264.111(b) 264.228(b)(1),
264.228(b)(3), and 264.228(b)(4)];
o cap slope, shape and drainage
construction to ensure stability and
minimize the effects of erosion, root
intrusion, and animal destruction [40
CFR §§ 192.32(b)(1), 264.111(a),
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 31 of 69
264.111(b) 264.228(b)(1),
264.228(b)(3), and 264.228(b)(4)];
o use of biosolids or top soil to facility
vegetation growth;
o the use of vegetation to emulate the
structure, function, diversity, and
dynamics of the native community to
maximize resilience and sustainability;
o erosion modeling to determine
effectiveness of cap design; and,
o a low permeability layer (liner) will be
placed between the NECR mine waste
and the tailings currently disposed
within the Tailings Disposal area.
[This layer will be constructed to
eliminate the possibility that the layer
will collect water and produce a
"bathtub effect". This layer will be
constructed of natural materials, not
synthetic, to eliminate the sudden
failure risk associated with punctures
and rips. This layer will be compacted
to meet a hydraulic conductivity17 of
no more than 1 x 10"7 centimeters per
second (cm/s)].
The UNC Site currently has three tailings
disposal cells containing an estimated 3.5
million tons of tailings covering approximately
100 acres. The estimated 1,000,000 cubic yards
of mine waste from the NECR Site is
approximately 1.35 million tons18. The 1.35
million tons of mine waste from the NECR Site
represents an approximate volume increase
within the Tailings Disposal Area of 38%.
For cost estimating purposes, the two remedial
action alternatives described in this Surface Soil
17 Hydraulic conductivity is defined as the rate of movement of
water through a porous medium. A hydraulic conductivity of 1
x 10"7 cm/s indicates that water will move at a rate of 0.0000001
centimeters over a time of one second.
18 The estimated volume of mine waste at the NECR site being
considered for disposal at the UNC Site within the Tailings
Disposal Area is approximately 1 million cubic yards. A
conversion factor of 1.35 cubic yards per tons was used to
convert the volume from cubic yards to tons.
008936
-------
OU Proposed Plan assume that NECR mine
waste would be added to the NRC-regulated
North and Central Cells at the UNC Site. A new
cap would be constructed over the mine waste
once it is added to the cells, which would add
additional height and protection against
infiltration. Figure 6 provides an example of a
generalized conceptual drawing showing one
possible outcome for the Tailings Disposal Area
after placement of the NECR mine waste. Final
design specifications, mine waste placement,
and the disposal configuration will be completed
during remedial design.
Under the NCP (40 CFR §300.430(f)(4)(ii)) and
CERCLA, if a remedial action is selected that
results in hazardous substances, pollutants, or
contaminants remaining at the site above levels
that allow for unlimited use and unrestricted
exposure, the lead agency shall review such
action no less often than every five years after
the initiation of the selected remedial action.
Since under Alternative 2, NECR mine waste
will be disposed on the UNC Site within the
Tailings Disposal Area, five year reviews will
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfimd Site
July 20, 2012 Page 32 of 69
be required. The capped area will require
Operation and Maintenance (O&M) activities as
necessary including cap inspections and
maintenance for continued cap stability, erosion
protection, and contaminant containment. In
addition, although ground water is not a
component of this Surface Soil OU Proposed
Plan, which addresses only the proposed
disposal of the NECR Site low level threat mine
waste at the UNC Site, ground water monitoring
and remediation of the contaminant plumes will
continue under the 1988 ROD as a separate
remedial action. The actions called for by the
1988 ROD include monitoring and reporting to
document potential contaminant migration and
to ensure compliance with ground water
remediation goals established under the 1988
ROD and any amendments to that ROD.
Alternative 2 supports the future reuse options
of residential and grazing for the NECR Site.
Alternative 2 will achieve all RAOs for the
UNC Site by preventing exposure through the
use of engineering controls (e.g., capping the
mine waste and tailings and fencing), by
UNC OFFICES
A* jO
/ Jy
* Jy
jf/
CENTRAL CELL
SOUTH CELL
EVAPORATION
PONDS
NEW MATERIAL/MINE WASTE
EXISTING TAIUNGS OlSPOSVU. AREA
EVAPORATION
PONDS
Section A (View from Evaporators Ponds)
LEGEND
EXISTING ROADS
FINISHED GROUND SURFACE
TAILINGS DISPOSAL AREA
fc
¦ ""'^,,1 - ' '
&ope??*
t
!
l.J J NEW MATERIAL/MINE WASTE
In I 1 1 ¦ - > - - u TAILINGS COVER SURFACE
DISTANCE Ft
Figure 6: Possible placement of mine waste at United Nuclear Corporation Mill Site
(unc) BSS».n
Mc* U-EY COOTY W MEX CO >¦>
NECR REMOVU ACT CM
HC
NORTH AMD CENTRAL CELL * DOMED SURFACE
MWH
FEB 2012
CONCEPTUAL ONLY - NOT FOR CONSTRUCTION PURPOSES (MODIFIED BY EPA FOR PROPOSED PLAN)
008937
-------
monitoring migration of contaminants at the
UNC Site and Tailings Disposal Area
boundaries, by enforcement of institutional
controls (IC) and site access restrictions, and by
the performance of site O&M. Under CERCLA,
the UNC Site will be restricted from uses other
than long-term care of the Tailings Disposal
Area. This means that residential, industrial, and
grazing uses will be prohibited. It is expected
that there would be a transfer of the UNC Site to
the DOE's Long-Term Surveillance and
Maintenance Program under DOE's Office of
Legacy Management. Under this DOE program,
the UNC Site would be maintained and
managed under the DOE to provide for
continued containment and protectiveness.
Currently, United Nuclear Corporation is
addressing source material and on-site surface
reclamation at the UNC Site under the direction
of the NRC, pursuant to United Nuclear
Corporation's NRC license. Under the license,
the NRC has released the mill facility and
buildings for unrestricted use. Currently, the
mill facility and buildings are being used by mill
personnel. The NRC has, pursuant to its license,
restricted use of the Tailings Disposal Area at
the UNC Site. The United Nuclear
Corporation's NRC license is an effective IC.
Under NRC's license termination process, the
site owner (in this case United Nuclear
Corporation) transfers title of the site to DOE
for long-term custody and care. DOE then
becomes the perpetual custodian of the UNC
Site under an NRC general license through the
Long-Term Surveillance and Maintenance
Program under DOE's Office of Legacy
Management (10 CFR § 40.28). This general
license to DOE is perpetual [10 CFR §
40.28(b)], Under the Legacy Management
Program, DOE conducts and maintains the site
to ensure remedy protectiveness. At the time
that the site owner's license terminates, the
UNC Site is expected to be transferred to DOE
under a general license allowing no other
permitted use of the UNC Site other than long-
term care of the disposal area. Once the UNC
Site is being managed by DOE under its general
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 33 of 69
license from the NRC, the general license will
serve as the IC. No other use of the UNC Site,
other than long-term care, will be permitted
unless the NRC grants a specific license
allowing such use of the surface or subsurface
[10 CFR § 40.28(d)],
The EPA will work closely with the NRC and
DOE to identify the necessary and appropriate
ICs as well as the process under which they will
be put in place and enforced. If the NRC does
not transfer all areas of the UNC Site to DOE at
the time that the UNC Site owner's license is
terminated, EPA will re-evaluate the need for
ICs and O&M activities for these areas since
DOE would not be managing these areas of the
UNC Site under these circumstances.
EVALUATION OF ALTERNATIVES
1. Overall Protection of Human Health and the
Environment
Alternative 1, the No Action Alternative, is
protective of human health and the environment
at the UNC Site to the extent that the status quo
at the UNC Site is protective. As noted in the
2011 Non-Time-Critical Removal Action
Memorandum, hazardous substances from the
NECR Site, if not addressed, may continue to
present an imminent and substantial
endangerment to public health or welfare or the
environment at NECR.
Alternative 2 will provide protection of human
health and the environment by eliminating,
reducing, and controlling risk through
containment using engineering controls and
restricting site use through ICs.
2. Compliance with ARARs
Alternative 1 does not change current UNC Site
conditions.
Alternative 2 will be designed and implemented
to meet Applicable or Relevant and Appropriate
Requirements (collectively ARARs) as those
terms are defined at 40 CFR § 300.5. Among
the ARARs it will meet are the requirements of
the National Emission Standards for Hazardous
008938
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfimd Site
July 20, 2012 Page 34 of 69
Air Pollutants [40 CFR §§61.92, 61.192,
61.222(a) and (b)] and the New Mexico
Administrative Code (NMAC) regulation of
non-coal mining which establishes requirements
for mine reclamation and close-out plans at
section 19.10.5.507A,19.10.6.603.A andB,
19.10.6.603.CI through 9, and 19.10.6.603.D
through H NMAC. Construction and materials
management will meet the following ARARs:
the Clean Water Act National Pollution
Discharge Elimination System stormwater
discharge [40 CFR §§ 122.26(c)(l)(i), 122.41,
122.42(a), 122.44(a)(1) and 40 CFR §
125.3(c)(3)] and the Uranium Mill Tailings
Radiation Control Act [40 CFR §§ 192.02(b)(1),
192.02(b)(2), 192.32(b)(1), 192.32(b)(l)(i), and
192.32(b)(1)(h)].
Nine Evaluation Criteria for CERCLA Remedial Alternatives
Overall Protection of Human Health and the Environment
determines whether an alternative eliminates, reduces, or
controls threats to public health and the environment through
institutional controls, engineering controls, or treatment.
Compliance with Applicable or Relevant and Appropriate
Requirements (ARARs) evaluates whether the alternative
meets Federal and State environmental statutes, regulations,
and other requirements that pertain to the site, or whether a
waiver is justified.
Long-term Effectiveness and Permanence considers the
ability of an alternative to maintain protection of human health
and the environment over time.
Reduction of Toxicity, Mobility, or Volume of
Contaminants through Treatment evaluates an alternative's
use of treatment to reduce the harmful effects of principal
contaminants, their ability to move in the environment, and the
amount of contamination present.
Short-term Effectiveness considers the length of time needed
to implement an alternative and the risks the alternative poses
to workers, residents, and the environment during
implementation.
Implementability considers the technical and administrative
feasibility of implementing the alternative, including factors
such as the relative availability of goods and services.
Cost includes estimated capital, periodic, and annual
operations and maintenance (O&M) costs, as well as present
worth cost. Present worth cost is the total cost of an alternative
over time in terms of today's dollar value. Cost estimates are
expected to be accurate within a range of +50 to -30 percent.
State/Support Agency Acceptance considers whether the
State and USEPA agree with the analyses and
recommendations, as described in the RI/FS and Proposed
Plan.
Community Acceptance considers whether the local
community agrees with the analyses of the alternatives and
preferred alternative. Comments received on the Proposed
Plan are an important indicator of community acceptance.
]
A
A
• What it SAYS
Overall Protection of
Human Health and the
Environment
Compliance with
ARARs
Long-Term
Effectiveness and
Permanence
Reduction of Toxicity,
Mobility or Volume
through Treatment
Short-Term
Effectiveness
Implementability
State Acceptance
Community Acceptance
What it MEANS
Docs the Remedy PROTECT people
and the environment?
Duet it C0MPIY with ,i I applir Jhle
federal, state and local LAWS?
Will it continue to be protective in the
FUTURE?
Is the nasty ituff DESTROYED,
RCDUCCDor CONTAINED?
Can EPA Protect Community. Workers
and Environment during
ColStruction?
Qn epa actually build iw
How much does it COST? Considering
both INITIAL capita cost! aid
ONGOING operating costs.
EPA receives comments from State
after proposed plan is issued. May
influence modifications to proposed
remedy.
EPA receives comments from
commjnity on proposed plan. May
influence mudifiidliiro lu remedy
008939
-------
The UNC Site preliminary list of ARARs is
provided in Table 1. The final list of ARARs
will be presented in the Final Surface Soil OU
ROD.
In addition to ARARs, this remedial action will
meet the following laws to the extent they are
pertinent: the Endangered Species Act, 16
U.S.C. §§ 1531 et seq:, The Native American
Graves Protection and Repatriation Act, 25
U.S.C. §§ 3001 et seq; the National Historic
Preservation Act, 16 U.S.C. §§ 470 et seq;
Archeological Resources Protection Act of
1979, 16 U.S.C. §§47000-47011; and American
Indian Religious Freedom Act, 42 U.S.C. §§
1996 et seq.
3. Long-term Effectiveness and Permanence
Alternative 1 does not change current UNC Site
conditions.
Alternative 2 will provide for long-term
effectiveness and permanence through the
disposal of mine waste within the Tailings
Disposal Area at the UNC Site. Final disposition
of the mine waste will require the construction
of a cap that will contain the mine waste,
prevent direct exposure, limit water infiltration,
and mitigate off-site migration. Cap
construction is a proven and effective
technology for management of contamination
by eliminating the exposure pathway; however,
this technology does not reduce the magnitude
of the residual risk or overall risk of the
contamination that is capped. The long-term
effectiveness and permanence of this alternative
is dependent on future maintenance activities
that ensure cap stability, integrity, and longevity
as well as the enforcement of ICs restricting site
use.
In response to concerns raised by the
community, EPA reviewed documents related to
the construction of the Tailings Disposal Area,
in order to determine the load effect that the
additional tailings from the NECR Site would
have on the tailings already disposed in the
Tailings Disposal Area. Further, at the request
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 35 of 69
of EPA, United Nuclear Corporation developed
computer models that simulated what would
happen to the tailings in the Tailings Disposal
Area under various scenarios (Dwyer, 2011).
The models showed that, due to
evapotranspiration, vertical drainage and the
lack of water recharge, excess free water no
longer existed within the tailings now located in
the Tailings Disposal Area. The remaining
water in the tailings now located in the Tailings
Disposal Area is within the water storage
capacity of the tailings and will be held within
the pore spaces. Any reduction in the tailings'
porosity due to the loading or weight of the
additional NECR mine waste will not create
excess or new free water that could be
"squeezed" out. Based on conservative
evaluations of the tailings profiles and model
sensitivity analyses, adding the mine waste from
the NECR Site to the tailings in the Tailings
Disposal Area at the UNC Site is not expected
to result in the release of additional tailings
liquid into the ground water or surrounding soil.
Based on these conclusions, disposal of the
NECR Site mine waste at the UNC Site Tailings
Disposal Area is not expected to interfere with
or affect the ongoing remediation efforts
regarding tailings or ground water at the UNC
Site. EPA recognizes the limitations of the
simulations and model results. During remedial
design, additional data will be collected and
evaluated to further refine, support, and verify
these conclusions.
EPA also reviewed the Mill Decommission
Report (UNC, 1993) and the Borrow Pit No. 2
Final Reclamation Report (Smith, 1996b).
These reports documented the placement of the
debris (e.g., concrete, steel, and wood) within
the Tailings Disposal Area, and described the
debris. Based on this documentation, it appears
that the debris was placed in the Tailings
Disposal Area in layers, flattened, mixed and
covered with soil, and compacted resulting in a
stable cells that have had negligible settling over
the almost 20 years since disposal.
Consequently, it is expected that the additional
weight that the mine waste from the NECR Site
008940
-------
will add to the tailings that are presently in the
UNC Site Tailings Disposal Area will have
negligible consequences on the stability of the
tailings cells (EPA, 2011b). Placement of mine
waste within the Tailings Disposal Area will be
designed and constructed in a manner that
promotes material stability and reduces the
potential for future subsidence.
4. Reduction of Toxicity. Mobility, or Volume
of Contaminants through Treatment
Alternative 1 does not change current UNC Site
conditions
Alternative 2: The NCP establishes an
expectation that EPA will use treatment to
address the principal threats posed by a site
wherever practicable [NCP at 40 CFR
§300.430(a)(l)(iii)(A)]. In general, PTWs are
those source materials considered to be highly
toxic or highly mobile which generally cannot
be contained in a reliable manner or would
present a significant risk to human health or the
environment should exposure occur.
Conversely, non-principal threat wastes are
those source materials that generally can be
reliably contained and that would present only a
low risk in the event of exposure. The manner in
which principal threats are addressed generally
will determine whether the statutory preference
for treatment as a principal element is satisfied.
No PTW from the NECR Site will be sent to the
UNC Site. This Surface Soil OU Proposed Plan
for the UNC Site addresses only low level threat
mine waste from the NECR Site is not
concerned with the PTW from the NECR Site;
therefore, treatment is not a principal element of
Alternative 2.
5. Short-term Effectiveness
Alternative 1 does not change current UNC Site
conditions.
Alternative 2: The design process and time
frame for Alternative 2 will require a detailed
design for the cap structure for mine waste
disposal within the Tailings Disposal Area at the
UNC Site. Additional coordination, design, and
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 36 of 69
preparation time related to the NRC license
amendment process (Step Two) also will be
required. Alternative 2 offers short-term
effectiveness in terms of construction and
transportation management to protect the
community, site worker, and environment over
the estimated four years of remedial action and
construction time.
Alternative 2 involves substantial construction-
related activity over an extended period of time
and requires management and engineering
actions to protect the community and the on-site
workers. Potential risks related to transportation
and disposal of mine waste and potential
fugitive dust emissions may be encountered.
During transportation and material handling
activities, dust suppression measures will be
conducted to reduce fugitive dust emissions and
associated impacts to the nearby community. In
addition, perimeter air monitoring stations will
be positioned and operated to monitor emissions
during construction activities to maintain a safe
working environment and to protect human
health and the environment. Potential exposure
and protection procedures for workers engaged
in these activities will be addressed in a health
and safety plan. Workers in the controlled areas
will wear the appropriate safety equipment and
implement safety practices such as air
monitoring and access control for authorized
personnel only. Site construction activities will
also include storm water management to
mitigate the potential for off-site migration of
mine waste during weather events. Alternative 2
provides a great degree of short-term
effectiveness for the on-site worker and the
local community.
Alternative 2 involves the transportation of mine
waste. This activity may result in some
inconvenience for and directly impact the local
residents during the construction time frame and
includes nuisance construction noise, increased
truck traffic on local roads, potential traffic
detours or re-routing, and potential accidents or
spills. Mitigation efforts may include using dust
suppression measures, restricting hours of
008941
-------
operation as necessary, and air monitoring. Bulk
carriers hauling mine waste would be securely
covered and weighed to document compliance
with total and axle load limits. A transportation
plan will be used to identify the routes of travel,
times of operation, and traffic rules. Emergency
spill containment and cleanup contingencies
would also be included in the transportation
plan to address mine waste spills. The short
travel distance under Alternative 2 could
potentially reduce construction time, reduce
transportation incidents on public roadways, and
reduce the estimated trucking emissions based
on total distance traveled. Based on these factors
Alternative 2 provides a great degree of short-
term effectiveness to the public.
In addition, as provided in the 2011 Non-Time-
Critical Action Memorandum, voluntary
alternative housing options will be offered to
those residents significantly impacted by
disruptions associated with the removal action.
Alternative 2 provides for short-term
effectiveness through the implementation of
plans, processes, and procedures that will reduce
the likelihood of exposure and meet RAOs
within a reasonable time frame.
6. Implementabilitv
Alternative 1 does not change current UNC Site
conditions.
Alternative 2 is technically feasible and would
require conventional techniques, materials or
labor for transportation and disposal. The site is
readily accessible, and roadway improvements
can be made to optimize access for equipment,
materials and labor. Disposal would be
scheduled and performed in a manner to
maximize work flow, minimize multiple mine
waste handling actions, and ensure worker and
public safety. Engineering controls for fugitive
dust and site monitoring would be utilized to
protect off-site areas. Stormwater and surface
water controls and improvements will be
developed and implemented to secure the area
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 37 of 69
during extreme storm events and mitigate off-
site migration.
Mine waste disposal and cap construction is a
proven and effective technology that can be
implemented using a variety of conventional
equipment and materials. Heavy equipment
needed for this project, such as scrapers,
excavators, dozers, loaders, compactors, and/or
bulk carriers, are commercially available.
Continued maintenance, repair, optimization,
and monitoring actions can be accomplished
using a variety of conventional and
commercially available equipment. Construction
materials for the cap and site restoration
activities are commercially available. In
addition, working space (temporary construction
office trailers), utilities (power, drinking water,
and telephone), portable sanitary services, and
refuse disposal are available.
Trained and experienced labor is available for
work activities. Special certifications and health
and safety training requirements to comply with
Occupational Safety and Health Administration,
radiation, and hazardous material handling
requirements are available and will be
maintained throughout the project.
Transportation of mine waste is required by
Alternative 2 which is subject to additional
considerations. Securing an adequate number of
specialized transporters with sufficient trucking
resources may be limited, and any delays in
excavation and loading may jeopardize the
availability or commitment by the transporters.
Alternative 2 is expected to require a high level
of effort to administratively implement the
remedial action. Implementation of this action
will require administrative coordination among
United Nuclear Corporation, DOE, NRC, EPA
Region 9, EPA Region 6, NNEPA, the
community, and the State of New Mexico. The
UNC Site is under EPA and NRC jurisdiction.
As outlined in the 2011 Non-Time Critical
Removal Action Memorandum, disposal of
mine waste from the NECR Site within the
008942
-------
Tailings Disposal Area at the UNC Site is
contingent on two actions being taken. This
Surface Soil OU Proposed Plan begins EPA's
process to fulfill step one: issuance of an
appropriate decision document consistent with
the NCP. Step two involves United Nuclear
Corporation's submittal of a request for an
amendment to its NRC license. The amendment,
if granted by NRC, after its review and
evaluation, would accommodate disposal of
mine waste from the NECR Site within the
Tailings Disposal Area at the UNC Site. NRC's
agreement to amend the United Nuclear
Corporation's license to allow this disposal will
be necessary to fulfill step two as described in
the 2011 Non-Time-Critical Removal Action
Memorandum.
7. Cost
Alternative 1 does not change current UNC Site
conditions.
Alternative 2: An order of magnitude cost
estimate was developed for Alternative 2. The
cost estimate was prepared for assistance with
comparing the relative costs between the various
remedial alternatives and is considered accurate
only to +50/-30 percent. For cost and evaluation
purposes, Operation and Maintenance (O&M)
activities were estimated over a 30 year period.
The 30 year time frame was chosen for
consistency and comparison purposes and does
not limit or alter the requirements for O&M into
the future. In addition, a discount factor of 7%
was used to calculate the present worth of costs.
The cost of Alternative 2 ($41.5 million)
includes the transportation of low level threat
mine waste from the NECR site and disposal of
that low level threat mine waste within the
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 38 of 69
Tailings Disposal Area at the UNC Site. The
estimated cost for Alternative 2 is subject to
substantial cost fluctuations related to changes
in fuel cost and transportation labor market
rates. Alternative 2 is considered cost-effective
based on an evaluation of its costs, proportional
to its overall effectiveness. See 40 CFR §
300.430(f)(l)(ii)(D).
8. State/Support Agency Acceptance
The State of New Mexico generally supports the
Preferred Alternative (NMED, 2012).
9. Community Acceptance
Community acceptance of the preferred
alternative will be evaluated after the public
comment period ends and will be described in
the responsiveness summary in the UNC Site
Surface Soil OU ROD.
SUMMARY OF THE PREFERRED
REMEDIAL ALTERNATIVE
Based upon consideration of the requirements of
CERCLA and the detailed analysis of
alternatives using the nine CERCLA evaluation
criteria the Preferred Alternative for mine waste
disposal is Alternative 2: On-site Disposal at the
UNC Site within the Tailings Disposal Area.
The Preferred Alternative is selected because it
provides protection of human health and the
environment, provides a great degree of long-
term effectiveness and permanence, and is
considered cost effective. Additionally, as
summarized in the NECR Site 2011 Non-Time-
Critical Removal Action Memorandum, on-site
disposal of the NECR Site mine waste at the
NECR Site was rejected by the Navajo Nation
and the community while off-site disposal at a
regulated facility was found to be cost
prohibitive and less cost effective than disposal
Summary of Remedial Alternatives and Estimated Cost
Alternative and Description
Estimated
Capital
Cost
Estimated
Annual
O&M
Estimated
Present Worth
Cost
Estimated
Construction
Timeframe
Alternative 1: No Action
Alternative
$0.00
Not
Applicable
Not Applicable
Not Applicable
Alternative 2: On-site
Disposal within the Tailings
Disposal Area
$40,337,281
$1,227,767
$41,565,048
4 Years
008943
-------
at the UNC Site. In addition, a post EE/CA
analyses of 11 other alternate disposal locations
determined that (EPA, 201 la) given the
administrative, legal and cost challenges
presented by each of the 11 locations, the UNC
Site was identified as the most suitable (EPA,
2011a).
The Preferred Alternative will adequately
protect human health and the environment and
comply with ARARs by eliminating, reducing
and controlling exposures to human and
ecological receptors through mine waste
disposal and containment of soil, mine waste,
and tailings within the Tailings Disposal Area at
the UNC Site and the enforcement of UNC Site
use restrictions. The Preferred Alternative meets
the RAOs through reduction of potential human
health risk levels such that exposure to mine
waste through external radiation, ingestion,
direct contact and inhalation does not exceed the
risk range. In addition, disposal and containment
reduces potential ecological risk levels for
terrestrial receptors such that the external
radiation, ingestion, direct contact, and
inhalation exposure pathways are incomplete.
UNC Site use restrictions will prohibit the
residential, industrial, or grazing use and will
restrict unauthorized access.
The Preferred Alternative is expected to achieve
substantial long-term effectiveness and
permanence through containment of the mine
waste. The Preferred Alternative is anticipated
not to pose any unacceptable short-term risks to
on-site workers, the community, or the
environment due to the implementation of
mitigation efforts to control off-site contaminant
migration (e.g., dust suppression actions or
stormwater/erosion controls). No cross-media
impacts are expected due to transportation and
disposal actions. The Preferred Alternative can
be implemented using common construction
practices and commercially available equipment
and services. The Preferred Alternative is
expected reach RAOs within a reasonable time
frame.
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 39 of 69
The NECR Site Consolidation Areas and the
UNC Site Tailings Disposal Area will be treated
as one for the purpose of remediation. Section
104(d)(4) of the CERCLA, 42 U.S.C. §
9604(d)(4), allows two or more noncontiguous
facilities that are reasonably related on the basis
of geography, or on the basis of the threat or
potential threat to the public health or welfare or
the environment, to be treated as one for the
purpose of remediation. Because of the
similarity of threat posed by the mine waste in
the areas on the NECR Site where mine waste
has been deposited and consolidated
(Consolidation Areas) and the threat posed by
the tailings in the covered pits and landfills that
make up the UNC Site Tailings Disposal Area,
as well as the relative proximity of these
facilities (less than 1 mile) EPA proposes to use
its authority under CERCLA Section 104(d)(4)
to temporarily combine the NECR Site
Consolidation Areas and the UNC Site Tailings
Disposal Area. The combination of these two
areas, the NECR Site Consolidation Areas and
the UNC Site Tailings Disposal Area is
temporary, and it is for waste disposal purposes
only.
The facilities that would be combined under
EPA's Section 104(d)(4) authority include the
areal extent of contamination at the
Consolidation Areas and the areal extent of
contamination at the UNC Site Tailings
Disposal Area and all suitable areas in very
close proximity to the contamination in both
areas necessary for implementation of the
response action. This temporary combination of
the two facilities will facilitate the
implementation of the Preferred Alternative for
the surface soil OU remedial action at the UNC
Site described in this Surface Soil OU Proposed
Plan, and it will facilitate the selected removal
action for the NECR Site identified in the 2011
Non-Time-Critical Removal Action
Memorandum for the NECR Site (EPA, 201 lb).
By combining the Consolidation Areas and the
Tailings Disposal Area, the Preferred
Alternative can be taken without State, Federal
or local permits as provided in CERCLA section
008944
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121(e), 42 U.S.C. § 9621(e). In addition,
combination of the Consolidation Areas and the
Tailings Disposal Area means that the action
transferring mine waste from the Consolidation
Areas to the Tailings Disposal Area will be an
on-site action that need not meet the
requirements of the procedures for planning and
implementing off-site response actions codified
at 40 CFR § 300.440 (the "Off-site Rule). In
short, treating the non-contiguous NECR and
UNC Sites as one for the purpose of disposing
NECR mine waste at the UNC Site "would be in
the best interests of achieving sound and
expeditious environmental cleanups." 55 Fed.
Reg. 8666, 8691 (1990).
Alternative 2 supports the future reuse options
of residential and grazing for the NECR Site and
will achieve all RAOs for the UNC Site by
preventing exposure through the use of
engineering controls (e.g., capping the mine
waste and tailings and fencing), by monitoring
migration of contaminants at the UNC Site and
Tailings Disposal Area boundaries, by
enforcement of institutional controls (IC) and
site access restrictions, and by the performance
of site O&M. Under CERCLA, the UNC Site
will be restricted from uses other than long-term
care of the Tailings Disposal Area, including
residential, industrial, and grazing uses.
Unauthorized access will be prohibited expect
for Long-Term Surveillance and Maintenance
Program maintenance personnel working under
DOE's Office of Legacy Management. Under
this DOE program, the UNC Site would be
maintained and managed under the DOE to
provide for continued containment and
protectiveness.
Currently, United Nuclear Corporation is
addressing source material and on-site surface
reclamation at the UNC Site under the direction
of the NRC, pursuant to United Nuclear
Corporation's NRC license. Under the license,
the NRC has released the mill facility and
buildings for unrestricted use. Currently, the
mill facility and buildings are being used by mill
personnel. The NRC has, pursuant to its license,
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 40 of 69
restricted use of the Tailings Disposal Area at
the UNC Site. The license is an effective
institutional control (IC). Under NRC's license
termination process, the site owner (in this case
United Nuclear Corporation) transfers title of
the site to DOE for long-term custody and care.
DOE then becomes the perpetual custodian of
the UNC Site under an NRC general license
through the Long-Term Surveillance and
Maintenance Program under DOE's Office of
Legacy Management (10 CFR § 40.28). This
general license to DOE is perpetual [10 CFR §
40.28(b)], Under the Legacy Management
Program, DOE conducts and maintains the site
to ensure remedy protectiveness. At the time
that the site owner's license terminates, the
UNC Site is expected to be transferred to DOE
under a general license allowing no other
permitted use of the UNC Site other than long-
term care of the disposal area. Once the UNC
Site is being managed by DOE under its general
license from the NRC, the general license will
serve as the IC. No other use of the UNC Site,
other than long-term care, will be permitted
unless the NRC grants a specific license
allowing such use of the surface or subsurface
[10 CFR § 40.28(d)],
The EPA will work closely with the NRC and
DOE to identify the necessary and appropriate
ICs as well as the process under which they will
be put in place and enforced. If the NRC does
not transfer all areas of the UNC Site to DOE at
the time that the UNC Site owner's license is
terminated, EPA will reevaluate the need for ICs
and O&M activities for these areas since DOE
would not be managing these areas of the UNC
Site under these circumstances.
Through this process, NECR mine waste will be
disposed within the Tailings Disposal Area at
the UNC Site reducing the mine waste footprint
by creating one consolidated location requiring
long-term maintenance and management for
continued protection of human health and the
environment. Consolidation of similar mine
waste is consistent with the current UNC
disposal action, can be managed using the same
008945
-------
remediation technology as the UNC tailings, is
not expected to cause or promote adverse affects
due to loading (Dwyer, 2011), is protective of
human health and the environment, and is
expected to be maintained by DOE in the long-
term. This surface soil OU proposed action is
consistent with and supports the 2011 Non-
Time-Critical Removal Action Memorandum as
well as the reasonably anticipated future land
use of residential and grazing for the NECR
Site. The Preferred Alternative will require
long-term monitoring, Site inspections, and
O&M to ensure the Tailings Disposal Area is
appropriately managed and maintained for
continued protection of human health and the
environment. In addition, a remedy review will
be conducted by EPA every five years as
provided in 40 CFR §300.430(f)(4)(ii) to
determine whether the site continues to be
protection of human health and the
environment.
Although, ground water is not a component of
this Surface Soil OU Proposed Plan, which
addresses only the proposed disposal of the
NECR Site low level threat mine waste at the
UNC Site, ground water monitoring and
remediation of the contaminant plumes is
ongoing and will continue under the 1988 ROD
as a separate remedial action. Mine waste
disposal within the Tailings Disposal Area is not
expected to interfere or affect the current ground
water remediation efforts. Mine waste disposal
will be designed and construction to provide for
continued protection against contaminant
migration into the ground water (see Summary
of Remedial Alternatives section) in support of
ongoing ground water remediation efforts.
Based on the information currently available,
the EPA believes the Preferred Alternative
meets the threshold criteria and provides the
best balance of tradeoffs between the two
alternatives with respect to the balancing and
modifying criteria. The Preferred Alternative is
expected to satisfy the statutory requirements of
CERCLA § 121(b) by being protective of
human health and the environment, complying
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 41 of 69
with ARARs, and utilizing permanent solutions
and alternative treatment technologies to the
maximum extent practicable.
In general, PTWs are those source materials
considered to be highly toxic or highly mobile
which generally cannot be contained in a
reliable manner or would present a significant
risk to human health or the environment should
exposure occur. Conversely, non-principal
threat wastes are those source materials that
generally can be reliably contained and that
would present only a low risk in the event of
exposure. No PTW from the NECR Site will be
sent to the UNC Site; therefore, this Surface
Soil OU Proposed Plan for the UNC Site
addresses only the low level threat mine waste
from the NECR Site. The waste acceptance
criteria for mine waste that will be disposed at
the UNC Site Tailings Disposal Area are 200
pCi/g or less of Ra-226 and/or 500 mg/kg or
less of uranium. Because no PTW from the
NECR Site will be sent to the UNC Site under
Alternative 2, this remedy need not meet the
statutory preference for the selection of a
remedy that involves treatment as a principal
element. The Preferred Alternative can change
in response to public comment or new
information.
COMMUNITY PARTICIPATION
The EPA and NMED provide information
regarding the cleanup of the UNC Site to the
public through public meetings, the
Administrative Record file for the Site, and
announcements published in the Gallup
Independent and Navajo Times. The EPA and
NMED encourage the public to gain a more
comprehensive understanding of the Site and the
Superfund activities that have been conducted.
The dates for the public comment period; the
date, location, and time of the public meeting;
and, the locations of the Administrative Record
files are provided on the front page of this
Surface Soil OU Proposed Plan.
008946
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 42 of 69
For further information on the United Nuclear Corporation
Superfund Site, please visit the locations identified on Page 1 to view
various site documentation or contact:
Ms. Katrina Higgins-Coltrain
Mr. Earle Dixon
Remedial Project Manager
Project Manager
EPA Region 6
New Mexico Environment Department
1445 Ross Avenue
1190 Saint Francis Drive
Dallas, Texas, 75202
Santa Fe, New Mexico, 87505
(214) 665-8143
(505) 827-2890
coltrain.katrina(2),epa. gov
earle. dixon@state. nm. us
Mr. Jason McKinney
Community Involvement Coordinator
EPA Region 6
1445 Ross Avenue
Dallas, Texas, 75202
(214) 665-8132
mckinney. j ason@epa. go v
008947
-------
References
Agency for Toxic Substances and Disease
Registry, 2011. Radium, Division of Toxicology
and Environmental Medicine ToxFAQs™. July
1999.
Agency for Toxic Substances and Disease
Registry, 2011. Radon, Division of Toxicology
and Environmental Medicine ToxFAQs™.
September 2008.
Canonie Environmental Services Corporation,
1991. Tailings Reclamation Plan as approved by
NRC March 1, 1991 License No. SUA-1475
Volumes 1 through 3, prepared for United
Nuclear Corporation, Church Rock Facility,
Gallup, New Mexico. August 30, 1991.
Canonie Environmental Services Corporation,
1995. As-Built Report, Central Cell Final
Reclamation, prepared for United Nuclear
Corporation, Church Rock Facility, Gallup,
New Mexico. June 20, 1995.
Chester Engineers, 2011. Technical
Memorandum Summarizing Two Reports on
Zone 3 Tailings Seepage Sourcing and
Groundwater recharge, with information
Update. August 18, 2011.
Chester Engineers, 2012. Email
correspondence: Zone 1 Question. April 23,
2012.
Dwyer, Stephen F., 2011. Evaluation of
Consolidation And Water Storage Capacity
Related To Placement Of Mine Material on the
Existing UNC Mill Site Tailings Impoundment.
May 2011.
New Mexico Environment Department, 2012.
Final Review of the Surface Soil Operable Unit
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 43 of 69
Proposed Plan for United Nuclear Corporation
Superfund Site. July 9, 2012.
MWH, 2007. Final Removal Site Evaluation
Report, Northeast Church Rock Mine Site,
prepared for United Nuclear Corporation.
October 1, 2007.
MWH, 2008. Supplemental Removal Site
Evaluation data tables, Northeast Church Rock
Mine Site, prepared for United Nuclear
Corporation. February 2008.
Smith Environmental Technologies
Corporation, 1996a. As-Built Report, South Cell
Final Reclamation, prepared for United Nuclear
Corporation, Church Rock Facility, Gallup,
New Mexico. April 22, 1996.
Smith Environmental Technologies
Corporation, 1996b. As-Built Report, Borrow
Pit No. 2 Final Reclamation, prepared for
United Nuclear Corporation, Church Rock
Facility, Gallup, New Mexico. August 28, 1996.
Smith Environmental Technologies
Corporation, 1997. As-Built Report, 1996 Final
Reclamation Construction, prepared for United
Nuclear Corporation, Church Rock Facility,
Gallup, New Mexico. March 28, 1997.
United Nuclear Corporation, 1989. Windblown
Tailings Cleanup Verification Report, license
No. SUA-1475. December 21, 1989.
United Nuclear Corporation, 1990. Windblown
Tailings Cleanup Verification Report, license
No. SUA-1475. November 21, 1990.
United Nuclear Corporation, 1993. Mill
Decommissioning report, license No. SUA-
1475. April 1, 1993.
U.S. Environmental Protection Agency, 1988a.
Remedial Investigation United Nuclear
008948
-------
Corporation Church Rock Site, Volumes 1 and
2. August 1988.
U.S. Environmental Protection Agency, 1988b.
Record of Decision Ground Water Operable
Unit. September 30, 1988.
U.S. Environmental Protection Agency, 2008.
Third Five-Year Review for the United nuclear
Corporation Ground Water Operable Unit,
Church Rock, McKinley County, New Mexico.
September 17, 2008.
U.S. Environmental Protection Agency, 2009.
Engineering Evaluation/Cost Analysis Northeast
Church Rock Mine Site, Gallup, New Mexico.
May 30, 2009.
U.S. Environmental Protection Agency, 2010.
Estimate Waste Cell Configuration at UNC
Office Area. November 1, 2010.
Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 44 of 69
and Potential Cell Sourcing to the Zone 3
Plume, Church Rock Site, Gallup, New Mexico.
January 19, 2004.
U.S. Nuclear Regulatory Commission, 1989.
Cleanup of Tailings at the Northeast Church
Rock Mine. Memorandum for Docket No. 40-
8907 from NRC Region IV, Uranium Recovery
Field Office, Denver, Colorado. October 31,
1989.
U.S. Nuclear Regulatory Commission, 2000.
NRC Regulatory Issue Summary 2000-23
Recent Changes to Uranium Recovery Policy.
November 30, 2000.
U.S. Environmental Protection Agency, 2011a.
Northeast Church Rock - Post EE/CA Analysis
of Alternatives, Alternative Off-Site Disposal
Locations. September 27, 2011.
U.S. Environmental Protection Agency, 2011b.
Action Memorandum: Request for a Non-Time-
Critical Removal Action at the Northeast
Church Rock Mine Site, McKinley County,
New Mexico, Pinedale Chapter of the Navajo
Nation. September 29, 2011.
U.S. Environmental Protection Agency and U.S.
Nuclear Regulatory Commission, 1988.
Memorandum of Understanding for Remedial
action at the UNC-Church Rock Uranium Mill
in McKinley County, New Mexico. Signed
August 26, 1988, and published September 28,
1988, 53 Fed. Reg. 37887.
USFilter, 2004. Rationale and Filed
Investigation Work Plan to Evaluate Recharge
008949
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Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Chemical-Specific ARARs and "to be considered" (TBC) Information
Media
Requirement
Requirement Synopsis
Status and
Rationale
Residual
Radioactive
Material
FEDERAL
Uranium Mill Tailings
Radiation Control Act of
1978 (UMTRCA),
as amended - Regulations at
40 CFR
§ 192.02(b)(1) and (2)
§ 192.02(c)
§ 192.02(d)
§ 192.32(a)(1) and (2)
§ 192.32(a)(4)(n)
§ 192.32(b)(1)(H)
Protect the public and the environment
from uranium mill tailings prior to
closure and post-closure
Substantive
requirements are
relevant and
appropriate to on-
site disposal
activities
involving residual
radioactive
material.
40 CFR §
192.02(c) and §
192.32(a)(2) are
relevant and
appropriate;
however, aspects
of these
regulations related
to ground water
are being
addressed under
the ground water
operable unit
record of decision
remedial action.
Air
FEDERAL
Clean Air Act (CAA) -
National Emission Standards
for Hazardous Air Pollutants
(NESHAPs)
40 CFR §61.92
Regulates airborne emissions of
radionuclides to nearest off-site
receptor during cleanup of Federal
facilities and licensed U.S. NRC
facilities. Emissions of radionuclides
cannot exceed 10 milli-Roentgen-
Equivalent-Man per year (mrem/yr).
Substantive
requirements are
applicable to
activities during
the remedial
action.
008950
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United Nuclear Corporation Superfund Site
July 20, 2012 Page 46 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Chemical-Specific ARARs and "to be considered" (TBC) Information
Media
Requirement
Requirement Synopsis
Status and
Rationale
Air
FEDERAL
Clean Air Act (CAA) -
National Emission Standards
for Hazardous Air Pollutants
(NESHAPs)
40 CFR
§ 61.192
§ 61.222(a) and (b)
Regulates airborne emissions of radon
from DOE facilities. A facility shall
emit no more than 20 picocuries per
square meter per second [pCi/(m2 -sec)
(1.9 pCi/(ft2 -sec)] of radon-222 as an
average for the entire source, into the
air. Once a uranium mill tailings pile or
impoundment ceases to be operational
it must be disposed of and brought into
compliance with this standard within
two years of the effective date of the
standard. If it is not physically possible
for an owner or operator to complete
disposal within that time, EPA shall,
after consultation with the owner or
operator, establish a compliance
agreement which will assure that
disposal will be completed as quickly
as possible.
Substantive
requirements
applicable to
activities during
Long-term
Stewardship after
closure.
Air
FEDERAL
Clean Air Act (CAA) -
National primary and
secondary ambient air quality
standards
40 CFR
§ 50.6
§ 50.7
National primary ambient air quality
standards define levels of air quality
with an adequate margin of safety, to
protect the public health. Regulates
airborne emissions of particulate matter
having an aerodynamic diameter less
than or equal to a nominal 10
micrometers or having an aerodynamic
diameter less than or equal to a
nominal 2.5 micrometers.
Substantive
requirements
applicable to
activities during
remedial action.
Air
STATE
New Mexico Air Quality
Control Act
§ 20.2.3 NMAC -
Ambient Air Quality Standards
Establishes ambient air quality
standards, performance standards for
specific sources of air pollutants, and
specifies monitoring methods
Substantive
requirements are
applicable during
remedial action.
Water
STATE
New Mexico Water Quality
Act
§20.6.2.2101 NMAC -
New Mexico Water Quality
Ground and Surface Water
Protections
Establishes water quality standards and
regulation limits on biochemical
oxygen demand, chemical oxygen
demand, settleable solids, fecal
coliform, and pH in effluent.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
008951
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United Nuclear Corporation Superfund Site
July 20, 2012 Page 47 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Chemical-Specific ARARs and "to be considered" (TBC) Information
Media
Requirement
Requirement Synopsis
Status and
Rationale
Water
STATE
New Mexico Water Quality
Act
Antidegradation Policy and
Implementation Plan for
Surface Water
§ 20.6.4.8.A(1) NMAC
Requires that existing instream water
uses are maintained and protected and
that no further water quality
degradation occur that would interfere
with or become injurious to existing
uses.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§20.6.4.12 NMAC
Describes general requirements for
compliance to meet water quality
standards, including monitoring
requirements. Also establishes the
minimum quantification level (MQL)
as the water quality standard in cases
where the numeric standard is below
the MQL.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§20.6.4.13 NMAC
General Surface Water Criteria -
Applicable to all surface water at all
times, unless a specific standard is
provided elsewhere in these
regulations.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§ 20.6.4.13.A NMAC
General Criteria - Bottom Deposits:
Requires that surface waters are free of
contaminants that will settle and
damage or impair benthic life or
significantly alter the bottom. These
requirements are applicable for any
remedial action that could cause
sedimentation or deposits into streams.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§ 20.6.4.13.B NMAC
General Criteria - Floating Solids,
Oils, and Grease: Requires that surface
waters are free from oils, scum, grease
and other floating material.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
008952
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 48 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Chemical-Specific ARARs and "to be considered" (TBC) Information
Media
Requirement
Requirement Synopsis
Status and
Rationale
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§ 20.6.4.13.CNMAC
General Standard - Color: Prohibits
the creation of any unnatural,
undesirable color or one that can
impair use off water by aquatic life.
These requirements are applicable if
any discharge would create color in
receiving water.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§ 20.6.4.13.D NMAC
General Criteria - Organoleptic
Quality: Prohibits impact of
unpalatable flavor to fish or offensive
odor. These requirements are
applicable if any remedial alternative
would create a discharge capable of
such impacts
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§ 20.6.4.13.E NMAC
General Standard - Plant Nutrients:
Prohibits the presence of plant nutrients
at concentrations that will produce
undesired aquatic life.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§ 20.6.4.13.F NMAC
General Standard - Toxic Pollutants:
Requires that surface water of the state
of New Mexico be free of toxic
pollutants in amounts, concentrations,
or combinations that affect the
propagation of fish.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§ 20.6.4.13.GNMAC
General Standard - Radioactivity:
Prohibits the radioactivity of surface
water from exceeding the criteria set
forth in the New Mexico Radiation
Protection Regulations.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§ 20.6.4.13.H NMAC
General Standard - Pathogens:
Requires that surface water be free of
pathogens.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
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Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Chemical-Specific ARARs and "to be considered" (TBC) Information
Media
Requirement
Requirement Synopsis
Status and
Rationale
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§20.6.4.13.1 NMAC
General Criteria - Temperature:
Prohibits the increase in temperature,
as measured from above the point of
discharge, by more than 2.7°C in a
stream (in addition to meeting
maximum temperature standards in §
20.6.4.101-899 NMAC). These
requirements are applicable to any
discharge to a stream/river.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§20.6.4.13.J NMAC
General Criteria - Turbidity: Prohibits
reduction in light transmission such
that aquatic life is impaired or there is a
substantial visible contrast with the
natural appearance of water. These
requirements are applicable to any
discharge that could increase turbidity.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§ 20.6.4.13.K NMAC
General Criteria - Total Dissolved
Solids: Requires that total dissolved
solids (TDS) attributable to other than
natural causes do not damage or impair
the normal growth, function or
reproduction of animal, plant, or
aquatic life.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§ 20.6.4.13.L NMAC
General Criteria - Dissolved Gases:
Requires that surface water be free of
nitrogen and other dissolved gases at
levels above 110% saturation.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
Water
STATE
New Mexico Water Quality
Act
Standards for Interstate and
Intrastate Surface Waters -
Water Quality Criteria
§20.6.4.900 NMAC-A,
C,D,F,G, H2
Establishes water quality standards that
consist of designated use(s) of surface
water, water quality criteria necessary
to protect use(s), and an anti-
degradation policy.
Substantive
requirements are
relevant and
appropriate to
protecting surface
water from runoff.
008954
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United Nuclear Corporation Superjund Site
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Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Chemical-Specific ARARs and "to be considered" (TBC) Information
Media
Requirement
Requirement Synopsis
Status and
Rationale
Soil/Mine
waste
FEDERAL
RCRA Manifest Requirements
40 CFR Part 262 Subpart B
Cradle to grave manifesting for mine
waste taken from NECR Site for
disposal at UNC Site Tailings Disposal
Area
The preamble to
the NCP and EPA
guidance calls for
manifesting of
transported waste
when CERCLA
section 104(d)(4)
is used to combine
sites.
008955
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Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Action-Specific ARARs and TBC Information
Media/
Activity
Requirement
Requirement Synopsis
Status and Rationale
Residual
Radioactive
Material
FEDERAL
Uranium Mill Tailings Radiation
Control Act of 1978 (UMTRCA),
as amended - Regulations at 40
CFR
§ 192.02(a)
Protect the public and the
environment from
residual radioactive
material.
Substantive requirements
are relevant and
appropriate to on-site
disposal activities
involving residual
radioactive material.
Residual
Radioactive
Material
FEDERAL
Uranium Mill Tailings Radiation
Control Act of 1978 (UMTRCA),
as amended - Regulations at 40
CFR
§ 192.32(a)(3)(i)
Protect the public and the
environment from
uranium mill tailings
impoundments that are
nonoperational through
the placement of a radon
barrier.
Substantive requirements
are relevant and
appropriate to on-site
uranium mill tailings
impoundments that are
nonoperational.
Residual
Radioactive
Material
FEDERAL
Uranium Mill Tailings Radiation
Control Act of 1978 (UMTRCA),
as amended - Regulations at 40
CFR
§ 192.32(a)(4)(i)
Protect the public and the
environment from
uranium mill tailings
impoundments that are
nonoperational through
monitoring the
effectiveness of the radon
barrier.
Substantive requirements
are relevant and
appropriate to on-site
uranium mill tailings
impoundments that are
nonoperational.
Residual Non-
Radioactive
Material
FEDERAL
Uranium Mill Tailings Radiation
Control Act of 1978 (UMTRCA),
as amended - Regulations at 40
CFR
§ 192.32(b)(1)
§ 192.32(b)(l)(i)
Protect the public and the
environment from
nonradiological hazards.
Substantive requirements
are relevant and
appropriate to on-site
surface impoundments
containing radiological
and nonradiological
hazards.
Hazardous
Wastes
FEDERAL
Resource Conservation and
Recovery Act (RCRA) of 1976,
as amended - Regulations at
40 CFR
§ 264.111(a)
§ 264.111(b)
Provides for general
closure performance
standards for disposal of
nonradiological hazards.
Substantive requirements
are relevant and
appropriate to on-site
surface impoundments
containing radiological
and nonradiological
hazards.
Hazardous
Wastes
FEDERAL
Resource Conservation and
Recovery Act (RCRA) of 1976,
as amended - Regulations at
40 CFR
§ 264.228(a)(2)(i)
§ 264.228(a)(2)(h)
§ 264.228(a)(2)(m)
Provides for closure
performance standards
for disposal of
nonradiological hazards
in surface
impoundments.
Substantive requirements
are relevant and
appropriate to on-site
surface impoundments
containing radiological
and nonradiological
hazards.
008956
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 52 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Action-Specific ARARs and TBC Information
Media/
Activity
Requirement
Requirement Synopsis
Status and Rationale
Hazardous
Wastes
FEDERAL
Resource Conservation and
Recovery Act (RCRA) of 1976,
as amended - Regulations at
40 CFR
§ 264.228(b)(1)
§ 264.228(b)(3)
§ 264.228(b)(4)
Provides for post-closure
requirements for
nonradiological hazards
left in surface
impoundments after
closure.
Substantive requirements
are relevant and
appropriate to on-site
surface impoundments
containing radiological
and nonradiological
hazards after closure.
40 CFR § 264.228(b)(3)
is relevant and
appropriate; however,
aspects of this regulation
related to ground water
are being addressed
under the ground water
operable unit record of
decision remedial action.
Soils
FEDERAL
Surface Mining Control and
Reclamation Act of 1977
(SMCRA), as amended ~
Regulations at 30 CFR
§ 816.95(a) and (b)
§ 816.111 (a), (b), and (c)
Establishes a program for
stabilization of surface
areas and revegetation
requirements
Substantive requirements
are relevant and
appropriate for protecting
the cap against erosion.
Air
FEDERAL
Surface Mining Control and
Reclamation Act of 1977
(SMCRA), as amended ~
Regulations at 30 CFR
§ 780.15(b)
Establishes a program for
fugitive dust control and
monitoring.
Substantive requirements
are relevant and
appropriate during
remedial action.
Radioactive
Material
FEDERAL
License Requirements for Land
Disposal of Radioactive Waste -
Regulations at
10 CFR
§61.41
§61.44
§61.51
§61.52
§61.53
Provides a variety of
performance objectives
and technical
requirements related to
land disposal.
Substantive requirements
applicable to activities
related to on-site disposal
of radioactive materials.
Aspects of these
regulations related to
ground water are being
addressed under the
ground water operable
unit record of decision
remedial action.
008957
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superjund Site
July 20, 2012 Page 53 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Action-Specific ARARs and TBC Information
Media/
Activity
Requirement
Requirement Synopsis
Status and Rationale
Water
FEDERAL
CWA -
Section 402, National Pollutant
Discharge Elimination System
(NPDES) Stormwater discharges -
40 CFR
§125.3(c)(3)
§125.3(d)(1), (2) and (3)
§125.3(e)
§125.3(f)
§125.3(h)
On-site discharges from
site are required to meet
the substantive CWA
requirements, including
discharge limitations,
monitoring and best
management practices
Substantive requirements
are applicable during site
remedial action activities.
Water
FEDERAL
CWA -
Section 402, National Pollutant
Discharge Elimination System
(NPDES) Stormwater discharges -
40 CFR
§ 122.26(c)(l)(i)
§ 122.41
§ 122.42(a)
§ 122.44(a)(1)
§ 122.44(e)
§ 122.44(i)(4)
§ 122.44(k)(2) and (k)(4)
On-site discharges from
site are required to meet
the substantive CWA
requirements, including
discharge limitations,
monitoring and best
management practices
Substantive requirements
are relevant and
appropriate if site runoff
is channeled directly to a
surface water body via
ditch, culvert, storm
sewer, or other means.
Solid Waste
STATE
New Mexico Solid Waste Act
Maximum Size, Siting Criteria,
Design Criteria.
§ 20.9.4.9 NMAC
Establishes siting criteria
for municipal, special
waste, and construction
and demolition waste
landfills and monofills
(scrap tires or asbestos
waste). Special waste is
defined as solid waste
with unique handling,
transportation or disposal
requirements to assure
protectiveness.
Substantive requirements
are relevant and
appropriate during
remedial action.
Solid Waste
STATE
New Mexico Solid Waste Act
Maximum Size, Siting Criteria,
Design Criteria.
§ 20.9.4.13.A.2 NMAC
§ 20.9.4.13.B NMAC
§ 20.9.4.13.E.l.a NMAC
Establishes design
criteria for municipal
landfills, special waste
landfills, and monofills.
Provides specific
requirements for liners.
Substantive requirements
are relevant and
appropriate for remedial
action.
008958
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superjund Site
July 20, 2012 Page 54 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Action-Specific ARARs and TBC Information
Media/
Activity
Requirement
Requirement Synopsis
Status and Rationale
Solid Waste
STATE
New Mexico Solid Waste Act
Maximum Size, Siting Criteria,
Design Criteria.
§ 20.9.4.14.A NMAC
§ 20.9.4.14.B.l, B.2, andB.3
NMAC
Provides testing and
quality control
requirements for
geosynthetic and soil
liners and final covers.
Substantive requirements
are relevant and
appropriate for remedial
action.
Solid Waste
STATE
New Mexico Solid Waste Act
Closure and Post-Closure
Requirements
§ 20.9.6.9.A.2 NMAC
§ 20.9.6.9.A.3 NMAC
Establishes closure and
post-closure
requirements for
municipal and special
waste landfills, including
cover thickness,
hydraulic conductivity,
erosion control and
revegetation.
Substantive requirements
are relevant and
appropriate for remedial
action completion.
Solid Waste
STATE
New Mexico Solid Waste Act
Closure and Post-Closure
Requirements
§20.9.6.12 NMAC
Establishes general
closure and post-closure
requirements for other
solid waste facilities,
including dismantling of
structures and other man-
made features.
Substantive requirements
are relevant and
appropriate for remedial
action completion.
008959
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superjund Site
July 20, 2012 Page 55 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Action-Specific ARARs and TBC Information
Media/
Activity
Requirement
Requirement Synopsis
Status and Rationale
Mining
STATE
New Mexico Mining Act
§ 19.10.5.507. A NMAC -
Regulation of Non-Coal Mining
Soil and Cover Materials.
Establishes performance
and reclamation
standards and
requirements. Requires
reclamation to a
condition that allows for
re-establishment of a
self-containing
ecosystem appropriate
for the life zone of the
surrounding areas
following closure, unless
conflicting with the
approved post-mining
land use. Provides for
waiver for open pit or
waste unit, if the open pit
or waste unit meets all
applicable federal and
state laws, regulations,
and standards for air,
surface water, and
ground water protection
following closure and
will not pose a current or
future hazard to public
health or safety.
Substantive requirements
are relevant and
appropriate for remedial
action completion.
Mining
STATE
New Mexico Mining Act
§ 19.10.6.603.A and B NMAC
§ 19.10.6.603.C.l through .9
NMAC
§ 19.10.6.603 .D through H NMAC
Soil and Cover Materials.
Establishes performance
and reclamation
standards for new mining
operations, including
impoundments.
Substantive requirements
are relevant and
appropriate for remedial
action completion.
008960
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superjiind Site
July 20, 2012 Page 56 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Action-Specific ARARs and TBC Information
Media/
Activity
Requirement
Requirement Synopsis
Status and Rationale
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2001 NMAC
Casing and Sealing of
Drilling Holes: General
Requirements: Requires
exposed underground
openings to be cased,
sealed, or otherwise
managed to prevent acid
or other toxic drainage
from entering ground or
surface water.
TBC during any
investigation work in and
around the site.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2003 NMAC
Casing and Sealing of
Drilling Holes and
Underground Openings -
Permanent: Requires
that permanent measures
are employed to prevent
acid or other toxic
drainage from entering
ground or surface water
from exposed
underground openings.
TBC during any
investigation work in and
around the site.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2005.E NMAC
Topsoil Substitutes and
Supplements: Selected
overburden material may
be substituted or may be
used as a supplement to
topsoil if determined by
the Director of the
administering state
agency that the resulting
soil medium is equal to
or more suitable for
sustaining vegetation.
TBC during remedial
action.
008961
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 57 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Action-Specific ARARs and TBC Information
Media/
Activity
Requirement
Requirement Synopsis
Status and Rationale
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2007 NMAC
Topdressing:
Redistribution -
Regraded land shall be
done in a manner that
will eliminate slippage,
achieve an approximate
uniform thickness,
prevent compaction and
is protected from erosion
before and after it is
seeded.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2008 NMAC
Topdressing: Nutrients
and Soil Amendments -
Requires that nutrients
and amendments be
applied to support the
revegetation
requirements.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2009.A, .B, .C, .D.l,
D.2, .D.4, .E.l, .E.2, andE.3
NMAC
Hydrologic Balance:
General Requirements -
Establishes actions to
prevent or minimize
water pollution. In no
case shall federal and
state water quality
statutes, regulations,
standards or effluent
limitations be violated.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2010 NMAC
Hydrologic Balance:
Water Quality Standards
and Effluent Limitations
- Requires that all
surface flow that leaves
the disturbed area shall
be made in compliance
with all applicable state
and federal water quality
statutes and regulations.
TBC during remedial
action.
008962
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 58 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Action-Specific ARARs and TBC Information
Media/
Activity
Requirement
Requirement Synopsis
Status and Rationale
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2011 NMAC
Hydrologic Balance:
Diversion and
Conveyance of Overland
Flow - Overland flows
from undisturbed areas
may be diverted from
disturbed areas if
required as necessary to
minimize erosion, to
reduce the volume of
water to be treated, and
to prevent or remove
water from contact with
acid- or toxic-forming
materials.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2013 NMAC
Hydrologic Balance:
Sediment Control
Measures - Requires
prevention, to the extent
possible, of additional
contribution of sediment
to streamflow or to run-
off outside the permit
area.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2014 NMAC
Hydrologic Balance:
Sedimentation Ponds -
Establishes standards for
sediment pond design,
sizing, construction and
maintenance.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2015 NMAC
Hydrologic Balance:
Discharge Structures -
Requires that discharges
from sediment ponds,
impoundments, dams,
embankments and
diversions shall be
controlled by energy
dissipaters, riprap
channels and other
devices.
TBC during remedial
action.
008963
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 59 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Action-Specific ARARs and TBC Information
Media/
Activity
Requirement
Requirement Synopsis
Status and Rationale
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2016 NMAC
Hydrologic Balance:
Acid Forming and Toxic
Forming Spoil -
Requires that drainage
from acid-forming
materials into ground and
surface water be avoided
and water is prevented
from coming into contact
with acid-forming spoil
in accordance with §
19.8.20.2056 NMAC.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2017 NMAC
Hydrologic Balance:
Permanent and
Temporary
Impoundments -
Establishes sizing and
construction standards
based on impoundment
classification. Static and
seismic safety factors for
impoundments are
relevant and appropriate
to similar structures.
Establishes minimum
static factor of safety
(FOS) of 1.3 for
impoundments.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2018 NMAC
Hydrologic Balance:
Ground Water Protection
- Establishes
requirements to control
the effects of mine
drainage and other mine
disturbances in such a
manner as to prevent or
control discharge of acid,
toxic or otherwise
harmful mine drainage
waters into ground water
systems and to prevent
adverse impacts on such
ground water systems.
TBC during remedial
action.
008964
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 60 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Action-Specific ARARs and TBC Information
Media/
Activity
Requirement
Requirement Synopsis
Status and Rationale
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2034 NMAC
Disposal of Excess
Spoils: General
Requirements - Requires
that spoil be placed in a
controlled manner to
ensure that leachate and
surface runoff from the
fill will not degrade
surface or ground water
or exceed the effluent
limitations and stability
of the fill and the land
mass are suitable for
reclamation and
revegetation.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2037 NMAC
Disposal of Excess
Spoils: Durable Rock
Fills - Establishes
standards for stability
(Factor of Safety), slope
gradient and surface
water diversion channel
sizing.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2050 NMAC
Air Resources Protection:
Fugitive Dust - Requires
that operators plan and
employ fugitive dust
control measures as an
integral part of site
reclamation operations.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2055 NMAC
Backfilling and Grading:
General Requirements -
Establishes minimum
requirements for
backfilling and grading
slopes.
TBC during remedial
action.
008965
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 61 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Action-Specific ARARs and TBC Information
Media/
Activity
Requirement
Requirement Synopsis
Status and Rationale
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2056 NMAC
Backfilling and Grading:
Covering Coal and Acid-
and Toxic-Forming
Material - Requires that
exposed acid- and toxic-
forming materials be
adequately covered with
non-toxic and non-
combustible materials.
Where necessary to
protect against adverse
effects on plant growth
from upward migrating
salts, erosion, and
formation of acid or toxic
seeps; and to provide an
adequate depth for plant
growth; the Director shall
specify thicker amounts
of cover using non-toxic
materials.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2059 NMAC
Regrading or Stabilizing
Rills and Gullies -
Requires that surface
areas be protected and
stabilized to effectively
control erosion.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2060 NMAC
Revegetation: General
Requirements - Requires
that all land effected by
mining shall be
revegetated to provide a
diverse, effective and
permanent vegetative
cover of the same
aspection native to the
area of disturbed land.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2061 NMAC
Revegetation: Introduced
Species - Allows for
introduced species to be
used for native species, if
approved.
TBC during remedial
action.
008966
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 62 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Action-Specific ARARs and TBC Information
Media/
Activity
Requirement
Requirement Synopsis
Status and Rationale
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2062 NMAC
Revegetation: Timing -
When necessary to
control erosion, any
disturbed area shall be
seeded and planted, as
contemporaneously as
practicable with the
completion of backfilling
and grading, with a
temporary cover of small
grains, grasses or
legumes until a
permanent cover is
established.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2063 NMAC
Revegetation: Mulching
and Other Soil
Stabilizing Practices -
Requires the use of
suitable mulch and other
soil stabilizing practices
on all regraded and
topdressed areas to
control erosion, promote
germination of seeds, or
increase the moisture
retention capacity of the
soil.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2065 NMAC
Revegetation: Standards
for Success - Establishes
vegetative success
measures for ground
cover and productivity.
TBC during remedial
action.
Mining
STATE
New Mexico Surface Mining Act
Coal Mining Regulations
§ 19.8.20.2066 NMAC
Revegetation: Tree and
Shrub Stocking -
Establishes standard of
success for tree and shrub
stocking.
TBC during remedial
action.
008967
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superfund Site
July 20, 2012 Page 63 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Location-Specific ARARs and TBC Information
Media
Requirement
Requirement Synopsis
Status and Rationale
Cultural
Resources
FEDERAL
The Native American Graves
Protection And Repatriation
Act -
25 United States Code (USC)
Section 3001 et seq and its
regulations Title 43 CFR Part
10.
Protects Native American
graves from desecration
through the removal and
trafficking of human remains
and cultural items including
funerary and sacred objects.
Substantive requirements
applicable if Native
American burials or
cultural items are
identified within area to be
disturbed
Cultural
Resources
FEDERAL
National Historic
Preservation Act -
16 USC 470 etseq; 36 CFR
Part 800
Provides for the protection of
sites with historic places and
structures
Substantive requirements
applicable if eligible
resources identified within
area to be disturbed
Cultural
Resources
FEDERAL
Archeological Resources
Protection Act of 1979 -
16 USC Sections 47000-47011;
43 CFR Part 7
Prohibits removal of or
damage to archaeological
resources unless by permit or
exception
Substantive requirements
applicable if eligible
resources are identified
within area to be disturbed
Cultural
Resources
FEDERAL
American Indian Religious
Freedom Act-
42 USC Section 1996 et seq.
Protects religious, ceremonial,
and burial sites, and the free
practice of religions by Native
American groups.
Substantive requirements
applicable if Native
American sacred sites are
identified within area to be
disturbed.
Wildlife
FEDERAL
ESA-
7 USC Section 136;
16 USC Sections 15331-1548,
Title 50 CFR Parts 17 and 402
Regulates the protection of
threatened and endangered
species or critical habitat of
such species
Substantive requirements
applicable if protected
species are identified
within area to be disturbed
Wildlife
STATE
NMSA 1978, §§ 17-2-37
through 17-2-46
Threatened and Endangered
Species. Provides for the
regulation and protection of
threatened and endangered
species.
Substantive requirements
applicable if protected
species are identified
within the area to be
disturbed
Wildlife
STATE
NMSA 1978, § 75-6-1
Endangered Plant Species.
Provides for the regulation
and protection of threatened
and endangered plant species.
Endangered plant species
means any plant species
whose prospects of survival
within the state are in
jeopardy or are likely within
the foreseeable future.
Substantive requirements
applicable if protected
species are identified
within the area to be
disturbed
008968
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superjund Site
July 20, 2012 Page 64 of 69
Table 1: Preliminary list of Applicable or Relevant and Appropriate Requirements.
Location-Specific ARARs and TBC Information
Media
Requirement
Requirement Synopsis
Status and Rationale
Wildlife
STATE
Title 19 Chapter 21 NMAC
Threatened and Endangered
Plants. Establishes
requirements for the
protection of threatened and
endangered flora and fauna.
Substantive requirements
applicable if protected
species are identified and
within the area to be
disturbed
Cultural
Resources
STATE
NMSA 1978, §§ 18-6-1
through 18-6-27
Historic Building Structures,
Sites, or Artifacts. Provides
for the preservation,
protection, and enhancement
of structures, sites, and
objects of historical
significance within the state.
Substantive requirements
applicable if protected
areas are identified and
within the area to be
disturbed
Cultural
Resources
STATE
NMSA 1978, §§ 18-8-1
through 18-8-8
Prehistoric or Historic Sites.
Provides for the acquisition,
stabilization, restoration or
protection of significant
prehistoric or historic sites.
Substantive requirements
applicable if protected
areas are identified and
within the area to be
disturbed.
Cultural
Resources
STATE
§ 4.10.12 NMAC
Prehistoric or Historic Sites.
Provides for the
implementation of the Act.
Substantive requirements
applicable if protected
areas are identified within
the area to be disturbed.
008969
-------
ACRONYMS
AOC
Administrative Order on Consent
ARARs
Applicable or Relevant and Appropriate Requirements
CERCLA
Comprehensive Environmental, Response, Compensation, and Liability Act
CFR
Code of Federal Regulation
COC
Contaminant of Concern
DOE
Department of Energy
EE/CA
Engineering Evaluation and Cost Analysis
EPA
U.S. Environmental Protection Agency
FR
Federal Register
HHRA
Human Health Risk Assessment
HI
Hazard Index
ICs
Institutional Controls
mg/kg
milligram per kilogram
MOU
Memorandum of Understanding
NCP
National Oil and Hazardous Substances Pollution Contingency Plan
NECR
Northeast Church Rock
NMED
New Mexico Environment Department
NNEPA
Navajo Nation Environmental Protection Agency
NPDES
National Pollution Discharge and Elimination System
NPL
National Priorities List
NRC
U.S. Nuclear Regulatory Commission
O&M
Operations and Maintenance
OU
operable unit
pCi/g
picocurie per gram
PRP
Potentially Responsible Party
PTW
Principal Threat Waste
Ra-226
Radium 226
RAOs
Remedial Action Objectives
RCRA
Resource Conservation and Recovery Act
ROD
Record of Decision
RSE
Removal Site Evaluation
UAO
Unilateral Administrative Order
UNC
United Nuclear Corporation
UNC/GE
United Nuclear Corporation/General Electric
U.S.C.
United States Code
008970
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Surface Soil Operable Unit Proposed Plan
United Nuclear Corporation Superjund Site
July 20, 2012 Page 66 of 69
GLOSSARY OF TERMS
Administrative Record - The body of documents available to the public associated with
characterization and remedy selection at a site.
Applicable or relevant and appropriate requirements (ARARs) - ARARs are the Federal and
State environmental laws that a selected remedy will meet. These requirements may vary among
Sites and alternatives.
Baseline Risk Assessment - An evaluation of the potential threat to human health and the
environment in the absence of any remedial action.
Byproduct Material - waste and tailings produced by the processing of ore for its uranium or
thorium content. Most of this material is created by uranium recovery and is primarily mill
tailings.
Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) -
Was enacted by Congress on December 11, 1980. This law created a tax on the chemical and
petroleum industries and provided broad Federal authority to respond directly to releases or
threatened releases of hazardous substances that may endanger public health or the environment.
Contaminants of Concern - Those chemicals associated with the Site or Site activities that may
represent a risk to human health or the environment.
Department of Energy, Office of Legacy Management - This office was established in
December 2003 to manage its responsibilities associated with the legacy of World War II and the
Cold War. This legacy includes radioactive and chemical waste, environmental contamination,
and hazardous material. The DOE program provides for long-term surveillance and maintenance,
records management, work force restructuring and benefits continuity, property management,
land use planning, and community assistance.
Engineering Controls - Controls that are engineered to manage environmental or human health
risk by limiting access and/or preventing exposure to contaminants of concern on the property.
These may include such things as fences, signs, or soil covers over contaminated materials.
Excess Lifetime Cancer Risk - Cancer risks posed by a contaminated site in excess of the
lifetime probability of developing cancer from other causes.
Ground water - Underground water that fills pores in soils or openings in rocks to the point of
saturation. Ground water is often used as a source of drinking water via municipal or domestic
wells.
Human Health Risk Assessment - A study that determines and evaluates excess lifetime risk
that site contamination poses to human health.
Institutional Controls (ICs) - Institutional controls are actions, such as legal controls, that help
minimize the potential for human exposure to contamination by ensuring appropriate land or
resource use.
NRC License - Through the licensing process, the U.S. Nuclear Regulatory Commission (NRC)
authorizes an applicant to conduct any or all of the following activities: Construct, operate, and
decommission commercial reactors and fuel cycle facilities; possess, use, process, export and
import nuclear materials and waste and handle certain aspects of their transportation; and/or site,
design, construct, operate, and close waste disposal sites.
Milligram per Kilogram (mg/kg) - A unit of measurement equivalent to one milligram of
contaminant per kilogram of solid (typically soil).
Monitoring - Ongoing collection of information about the environment that helps gauge the
effectiveness of a cleanup action.
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National Oil and Hazardous Substance Pollution Contingency Plan (NCP) - Regulations
governing cleanups under EPA's Superfund program.
National Priorities List (NPL) - The NPL is the list of national priorities among the known
releases or threatened releases of hazardous substances, pollutants, or contaminants throughout
the United States and its territories. The NPL is intended primarily to guide the EPA in
determining which Sites warrant further investigation.
U.S. Nuclear Regulatory Commission - The NRC was created as an independent agency by
Congress through the establishment of the Energy Reorganization Act of 1974 to ensure the safe
use of radioactive materials for beneficial civilian purposes while protecting people and the
environment. The NRC regulates commercial nuclear power plants and other uses of nuclear
materials, such as in nuclear medicine, through licensing, inspection and enforcement of its
requirements.
picocurie per gram (pCi/g) - A curie (symbol Ci) is a measurement of radioactivity and is
defined as 37 billion (37,000,000,000 ) disintegrations per second (1 Ci = 3.7* 1010). This is
roughly the activity of 1 gram of the radium isotope 226Ra, a substance studied by the pioneers
of radiology, Marie and Pierre Curie, for whom the unit was named. Picocurie (pCi) is 1 million
millionth of a curie (1 x 10"12 Ci). Picocurie per gram is the measurement of radioactivity per
gram of material.
Preferred Alternative - Proposed remedial alternative that meets NCP evaluation criteria and is
supported by regulatory agencies.
Present Worth Cost - A method of evaluation of expenditures that occur over different time
periods. By discounting all costs to a common base year, the costs for different remedial action
alternatives can be compared on the basis of a single figure for each alternative. When
calculating present worth cost for Superfund sites, total operations & maintenance costs are to be
included.
Radium-226 - decay product of Uranium-238.
Radiation - energy that travels in the form of waves or high speed particles.
Radioactive Decay - process where an unstable radionuclide emits energy or particles resulting
in transformation of the radionuclide into another radionuclide.
Radioactivity -the property of some atoms that causes them to spontaneously give off energy as
particles or rays. Radioactive atoms emit ionizing radiation when they decay.
Radon-222 - decay product of Radium-226.
Record of Decision (ROD) - A formal document that is a consolidated source of information
about a Superfund site, the remedy selection process, and the selected remedy.
Receptor - An organism that receives, may receive, or has received environmental exposure to a
chemical.
Remedial Action - Action(s) taken to correct or remediate contamination.
Remedial Action Objectives (RAOs) - Specific goals for protecting human health and the
environment. RAOs are developed by evaluating ARARs that are protective of human health and
the environment and the results of the remedial investigations, including the human and
ecological risk assessments.
Removal Action - A short-term immediate action taken to address releases of hazardous
substances that require expedited response.
Resource Conservation and Recovery Act (RCRA) - The Federal act that established a
regulatory system to track hazardous wastes from the time they are generated to their final
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disposal. RCRA also provides for safe hazardous waste management practices and imposes
standards for transporting, treating, storing, and disposing of hazardous wastes.
Tailings - the remaining portion of the metal-bearing ore after some or all of such metal, such as
uranium, has been extracted.
United Nuclear Corporation and United Nuclear Corporation/GE - operator of the NECR
Mine and UNC Mill and is now an indirect subsidiary of General Electric Corporation ("GE").
Operable Unit - term used to designate each separate action taken at a Superfund Site.
Uranium Mill Tailings Radiation Control Act - To provide for the disposal, long-term
stabilization, and control of uranium mill tailings in a safe and environmentally sound manner
and to minimize or eliminate radiation health hazards to the public, Congress enacted the
Uranium Mill Tailings Radiation Control Act of 1978 (UMTRCA). This Act established two
programs to protect the public and the environment from uranium mill tailings: Title 1 and Title
2 programs. The UMTRCA Title I program established a joint Federal/State-funded program for
remedial action at abandoned mill tailings sites where tailings resulted largely from production
of uranium for the weapons program. Under Title I, the Department of Energy (DOE) is
responsible for cleanup and remediation of these abandoned sites. The NRC is required to
evaluate DOE's design and implementation and, after remediation, concur that the sites meet
standards set by the Environmental Protection Agency (EPA). The UMTRCA Title II program is
directed toward uranium mill sites licensed by the NRC or Agreement States in or after 1978.
Title II of the Act provides the NRC authority to control radiological and non-radiological
hazards; the EPA authority to set generally applicable standards for both radiological and non-
radiological hazards; and the eventual State or Federal ownership of the disposal sites, under
general license from NRC. The UNC Site falls under the Title 2 program.
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USE THIS SPACE TO WRITE YOUR COMMENTS
Your input on the Surface Soil Operable Unit Proposed Plan for the UNC Site is important to the
EPA and NMED. Comments provided by the public are valuable in helping the EPA and NMED
select a final cleanup remedy for the Site. You may use the space below to write your comments,
then fold and mail. Comments must be postmarked by September 21. 2012. If you have any
questions about the comment period, please contact Katrina Higgins-Coltrain at (214) 665-8143
or through EPA's toll-free number at 1-800-533-3508, Jason McKinney at (214) 665-8132 or
through EPA's toll-free number at 1-800-533-3508, or Earle Dixon, NMED, at 505-827-2890.
Those with electronic communications capabilities may submit their comments to the NMED or
EPA via Internet at the following e-mail addresses: coltrain.katrina@epa.gov,
mckinney.jason@epa.gov, or earle.dixon@state.nm.us.
Name _
Address
City
State
Zip
008974
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