oEPA
United States
Environmental Protection
Agency
U.S. Environmental Protection Agency (EPA)
Callahan Mine Superfund Site
Brooksville, ME
EPA Superfund Community Involvement
Proposed Plan
You are Invited to Attend!
A public information meeting to learn about and
openly discuss the proposed plan will be held
July 9,2009. A Public Hearing with a Formal Com-
ment Session to provide citizens the opportunity to
enter official comments for the public record about
this proposed plan will be held on August 6,2009.
Public Information Meeting
July 9,2009
7:00 p.m.
Brooksvilie Town Office,
I Town House Road
Brooksville, ME
Public Hearing
August 6.2009
7:00 p.m.
Brooksvi lie Town Office,
I Town House Road
Brooksville, ME
Your Opinion Counts!!
EPA will be accepting public comment on this
cleanup proposal from July 10,2009 through
August 10,2009.You do not have to be a techni-
cal expert to comment. If you have a concern or
preference regarding EPA's proposed cleanup plan,
EPA wants to hear from you before making a final
decision on how to protect your community,
To provide comments on the
Proposed Plan,you may:
Offer oral comments during the public hearing
on August 6,2009 (see page 10 for details). Or
Send written comments postmarked no later
than
August 10,2009 to:
Edward Hathaway, RPM
U.S. EPA Region I
I Congress Street, Suite 1100 (HBT)
Boston, MA 02114-2023 Or
E-mail comments by August 10,2009 to:
h ath away, e d @ epa.gov
For further information about this meeting, call
EPA Community Involvement Coordinator Pam
Harting-Barrat (617) 918-1318, or toll-free at
1-888-372-7341 ext.81318.
The Cleanup Proposal for Callahan Mine
EPA proposes the following cleanup action, known as Alternative CMS2,for Operable
Unit I (OUI) and an Early Action for Operable Unit 2 (OU2). (Details regarding the
cleanup approach begins on page 7)
The Proposed OUI Cleanup Action consists oft
• Excavation of soil with PCS concentrations above the cleanup levels and disposal
of the PCB waste at an appropriate off-site facility;
• Excavation of soil within the Residential Use Area of the Site that contains lead
and arsenic above the residential cleanup levels
• Excavation of the waste rock/source materials in the Ore Pad, Waste Rock Pile 3
(WRP-3), and Mine Operations Area and subaqueous disposal in a confined
aquatic disposal (CAD) cell in the former mine pitWaste rock or soil commingled
with petroleum contamination will be disposed off-site;
• Dredging of the Southern Goose Pond mine waste hot spot and the adjacent
salt marsh sediments with contaminant concentrations above the cleanup levels
and subaqueous disposal in the CAD cell in the former mine pit;
• Capping of theTailings Impoundment with surface water diversion around and
a horizontal drain within theTailings lmpoundment.As part of the capping, the
Tailings Impoundment will be stabilized;
• Installation of a wetlands treatment system to treat the discharge of
contamination from the horizontal drain that will be installed within theTailings
Impoundment;
• Land use controls to prevent disturbance of the Tailings Impoundment cap,
treatment wetland, monitoring wells, CAD cell and any other component of
the OU I remedy; and
• Restoration of disturbed areas, including wetlands, and the possibility of mine
waste removal in Goose Cove and Goose Pond as part of the wetland mitigation
activities.
Long-term monitoring and maintenance would be performed to maintain the
effectiveness of the cleanup. EPA would perform a review of this remedial action
every five years.
The proposed Earty Action for OU2 would consist of fend use restrictions to prevent future
residential use or groundwater consumption for the areas of the former Callahan Mine
property portion of the Site that exceed the residential cleanup levels for soil or drinking
water risk levels.
EPA is also seeking public comment on EPA's finding under thelbxic Substances Control
Act (TSCA) regarding the PCB cleanup level to be used for the remedy. In addition, EPA
requests public comment on the Agency's finding that the cleanup represents the least
damaging practical alternative regarding potential impacts to wetlands. Page 7 contains
more detail regarding these items.
continued >
In accordance with Section 117 of die Comprehensive Environmental Response,
Compensation, and Liability Act, as amended (CERCLA) 42 U.S.C.§960I etseq.,the
taw that established the Superfund Program, dris document summarizes EPA's cleanup
proposal for the Callahan Mine Superfund Site. For detailed information regarding
the options evaluated for use at the Site, see die Callahan Mine Feasibility Study,
which is available for review at the Site information repositortes.The Site information
repositories are located at the Brooksvilie Library, Brooksville, Maine and at EPA's
Record Center at I Congress Street in Boston, MA (See page 10 for more details.)
SDMSDocID 452677
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A brief history of the
Call ah an Mine Site
•I
Int
• 1881 - 1964:
Intermittent mining operations occur
at the Site using underground shafts and
tunnels. About 10,000 tons were mined;
* 1965- 1968:
Site work began to prepare for open-pit
mining.Two dams were installed to drain
Goose Pond, and surface water was
diverted to Weir Cove;
* 1968- (972:
Mining operation removed approximate-
ly 5 million tons of waste rock to access
0,8 million tons of ore for processing.
The ore contained zinc, copper, lead, and
cadmium;
• 1972:
Mining operations ceased and the mine
pit measuring 600 feet in diameter and
300 feet deep was left in place.The
dams were breached to allow Goose
Pond to fill.The former mine pit remains
submerged within Goose Pond;
• 1987:
Four underground storage tanks were
removed;
* 1985:
Maine DEP completed Site Inspection
Prioritization Report;
.[999;
Maine DEP conducted Expanded Site
Inspection;
•2001:
EPA prepared Hazard Ranking Docu-
ment package to evaluate listing of the
Site on Superfund National Priorities
Ust;
* 2002:
Callahan Mine Superfund Site was added
to the National Priorities List
• 2004:
EPA began Remedial Investigation and
Feasibility Study (RI/FS);
• 2005:
State of Maine entered into Administra-
tive Order to complete RI/FS; and
• 2009:
OUI RI/FS completed and EPA issues
Proposed Plan.
What areas were
evaluated in the Rl?
The Callahan Mine Superfund Site (Site) is
located in the village of Harborside in the
Town of Brooksville, Maine.The Site is located
approximately 15 miles west of the Town of
Blue Hill and 35 miles west of the Town of
Bar Harbor on the northwest side of the
Cape Rosier peninsula on Penobscot Bay.
The Site includes the former Callahan Mine
property, an elongated 120-acre property
oriented north-south and accessed from
Goose Falls Road, Goose Pond and Goose
Cove. The Holbrook Island Sanctuary State
Park is immediately east of the Site. Private
residences and seasonal homes are located
adjacent to the former Callahan Mine
property on Old Mine Lane, Goose Falls Road
and Cape Rosier Road.
TheOUl Rl evaluated the entirestijdyaneashown
on Figure I .A substantial investigation program
was implemented to identify the nature and
extent of contamination and document threats
to human health and the environmentTable I lists
the investigations that were performed.The basic
conclusions of the OU I Rl are listed below:
• Mining and mining related activities
have left a legacy of contamination at
the Site. The land portions of the
Site include waste piles and access
roads that contain levels of
contamination higher than adjacent
areas and background concentrations;
* PCBs were detected in a small area
where the former ore processing facility
was located;
* Arsenic, cadmium, copper, lead,and zinc
are the contaminants most often
detected above background levels
and greater than health or ecological-
based screening levels for soil;
• Cadmium is the most significant
contaminant in groundwater with lead,
manganese, copper, zinc, and arsenic
also being detected above federal or
state criteria;
• Four areas within Goose Pond and
Goose Cove that were associated
with past mine operational activities
have the highest sediment concentrations
of copper, lead, and zinc at the Site;
• Copper and zinc were detected above
federal and state water quality criteria
in Goose Pond surface water
immediately adjacent to the Site;
• The sediment transport modeling
and Rl data suggest that the sediment
contamination is not migrating from
the Site to Penobscot Bay; and
• The Tailings Impoundment does not
meet safety criteria for long-term
stability.
How did the Site
become contaminated?
The presence and widespread distribution of
arsenic, copper, lead, and zinc are attributed to:
spillage during transport, storage, and handling
of ore and ore concentrate; disposal of tailings
and waste rock; and contaminated wind blown
dustAlthough much of the waste rock removed
during development of the open pit did not
contain iron sulfide and low grade ore.other sub-
ore grade waste rock contained iron sulfide and
lesser amounts of copper, lead, and zinc-bearing
minerals. Use of waste rock for fill across the Site,
particularly for containment berms and site roads,
contributed to site contamination.
In addition, there is a relatively small area of
PCB contamination attributed to historical
transformer leakage as well as a relatively small
area of oil and gasoline contamination attributed
to leaking underground storage tanks removed in
1987. Both of these areas are located within the
Mine Operations Area. PCBs were detected at a
concentration up to 7,900 mg/kg. Four seasonal
residential lots within the Residential Use Area
of the Site have soil contaminated with arsenic
and lead.
Based on historical information, the primary
source of the sediment contamination in
Southern Goose Pond and the adjacent salt
marsh is overflow from theTailings Impoundment
— either through the decant pipe or via overflow
ditches at the northwest and southwest comers.
Overflow from the northwest comer was a
likely source of salt marsh contamination. A
sedimentation basin constructed in Southern
Goose Pond to contain overflow and decant
discharge from the Tailings Impoundment also
contributed to the sediment contamination.
Discharge of contaminated groundwater
through seeps and weathering of waste rock via
acid rock drainage, followed by surface water
transport of suspended and dissolved material,
likely contributed to sediment contamination.
Overflow from the tailings impoundment and
groundwater/seep discharge continue today.
At WRP-3, weathering of waste rock via acid
rock drainage followed by groundwater/seep
and surface water transport of suspended and
dissolved material also appear to be historical and
potentially ongoing contributors to the Goose
Pond estuary contamination.
The sediment contamination in Goose Cove
and Dyer Cove are believed to be a result of
mine operations. During early mine operation,
groundwater seepage into the pit and entrained
rock dust were pumped to an outfall in Goose
Cove. Because of concerns about sediment
accumulation in Goose Cove, Dyer Cove was
dammed off and used as a settling pond for de-
watering die open pit. Following settling, water
in Dyer Cove was pumped to the mine water
sump, where it was then pumped through a pipe
that discharged into Goose Cove. In addition,
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contaminated surface water runoff during and
after mine operations as wdl as the discharge of
contaminated groundwater are interpreted as
historical and ongoing contributors to Dyer Cove
sediment contamination.
During closure of the mine: the Goose Falls dam
was breached, restoring limited tidal exchange in
Goose Pond;the Marsh Creek dam was breached;
and the pit and estuary were re-floocled.Although
some rock and overburden debris were pushed or
blasted into the pit at the time of mine closure, the
pit remains submerged with a relatively thin mande
of accumulated sediment that drapes the former
roads and pit bottom. Figure 2 shows die areas of
die Site that were used in the mine operations.
Why is Cleanup Needed?
EPA has identified current and future potential
threats to human health and the environment at
the Callahan Mine SiteA detailed summary of the
threats can be found in the OUI RI/FS Reports.
The key findings are presented below.
Threats to Human Health:
• PCBs are present in the soil of the Mine
Operations Area at levels that are unsafe
for even occasional human contact;
• Lead and arsenic are present in the soil
at concentrations that are not safe for
year round residential exposure; and
• Groundwater in certain areas of the Site
is unsuitable for human consumption.
The most highly contaminated groundwater
is located beneath the Ore Pad.
Threats to the Environment:
• Sediments in Southern Goose Pond that
contain mine waste along with high
levels of copper, lead, and zinc, were found
to be acutely toxic to benthic
organisms;
• Lead and other metals were found to be
accumulating in biota at the Site, including
fish, crabs, clams, and salt grass;
• Food chain modeling identified the
sediments in Southern Goose Pond and
the adjacent salt marsh as a threat to insect
and fish-eating birds;
• Surface water contains copper and zinc
above levels that could adversely impact
aquatic organ isms; and
* Water discharging from the waste
areas (seeps), particularly WRP-3,
significantly exceeds levels that could
adversely impact aquatic organisms.
EPA has identified the above conditions as
an unacceptable threat to human health and
the environment. The OU I Feasibility Study
was developed to identify cleanup options to
protect human health and the environment
Scope and Role of
this cleanup action
The cleanup action presented in this Proposed
Ran will be the first cleanup action for the Callahan
Mine Site. EPA often implements a cleanup action in
phases or"Operabie Units".This allows for a focus
on the portions of the Site where more immediate
risk reduction is necessary and can provide more
time to better understand other areas of the Site,
For the Callahan Mine Site, EPA is creating two
Operable Units. Operable Unit I (OU I) will target
the following threats to human heafth and the
environment, which are shown in Figure 3:
• Soil and waste contaminated with
PCBs;
• Soil and waste that represent the most
significant threat to surface water,
sediments, and groundwater;
• Areas of sediment that were shown to
be acutely toxic and represent a food
chain threat; and
• Soil and waste contaminated with lead
and arsenic in areas with current
residential use.
An Early Action will also be implemented for
Operable Unit 2 (OU2).The OU2 Early Action
will address the future potential threat from
ingestion of gnoundwater or direct contact with
contaminated soil/waste within the former Callahan
Mine property portion of the Site.The Early Action
includes the implementation of land use restrictions
on the former Callahan Mine property portion of
the Site to:
• Prevent the installation of water supply
wells; and
• Prevent residential development
The area where institutional controls will be
implemented as part of Early Action for OU2 is
shown in Figure 4.
The remaining components of OU2 will address
site wide groundwater contamination and site
wide soil contamination. OU2 will also evaluate
the success of OU I to determine whether any
additional actions are necessary to achieve the
cleanup objectives for surface water and sediment
A supplemental Rl Report and revised Human
Health Risk Assessment (HHRA) and Baseline
Ecological Risk Assessment (BERA) reports may
be devetaped for OU2.
Remedial Action
Objectives for OU I
EPA develops Remedial Action Objectives
(RAOs) for each cleanup action. The specific
RAOs for OU I are presented in Section 2.2 of
the FS and are summarized below:
• Prevent contact with soil or waste
containing PCBs above the cleanup
levels;
• Prevent contact with soil or waste with
lead or arsenic above the cleanup levels
in the area of the Site with current
residential use;
• Prevent exposure of biota to sediment,
including the sediment/soil in the
salt marsh, with concentrations of copper,
lead, or zinc that may represent a threat
to insectivorous and piscivorous birds,
fish, and other aquatic organisms;
• Minimize impacts from waste rock and
tailings within the OU I area on
groundwater, surface water, and
sediment;
• Stabilize the Tailings Impoundment to
achieve acceptable stability criteria;
• Comply with the applicable or relevant
and appropriate federal and state
regulations (ARARs) that apply to the
cleanup action; and
• Minimize impacts of waste rock and
tailings within the OU I area on
groundwater, surface water, and
sediment
The RAOs for OU2 are listed on page 9.
Cleanup Levels
In addition to the RAOs, EPA also identified the
cleanup levels that will be used to determine if
the OU I cleanup action is protective of human
health and the environment The human health
based cleanup levels for soil were developed based
on the exposure assumptions used in the human
health risk assessment except for the residential
cleanup level for arsenic which was set at the
background levet.The cleanup levels for sediment
and wetlands were based on the ecological food
chain modeling and the sediment toxictty testing.
The cleanup levels for the OU I Remedial Action
are presented below:
Table 2
Human Health Based
Cleanup Levels
Soil Residential Recreational
Land Use Land Use
Arsenic
Lead
PCBs
I4mg/kg
375 mg/kg
Img/kg
Table 3
30 mg/kg
700 mg/kg
Img/kg
Cleanup Levels for
Sediment and Wetlands
Sediment Safe Level for
aquatic biota and birds
Copper
Lead
Zinc
790 mg/kg
710 mg/kg
5100 mg/kg
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Areas of the Site Where OUI
Cleanup Action is Necessary
The information from the OUI Rl, HHRA,
and BERA was used to identify the areas that
were evaluated in the OU I FS for cleanup.
These areas of the Site that represent the
most significant threats to human health and
the environment are the: mine waste source
areas; southern Goose Pond and salt marsh
sediments; and residential use area.These areas
are summarized below and are shown in the
Figure 3.
Mine Waste Source Areas
There are four significant mine waste source
areas at the Site:
• Ore Pad: This area covers about 2.1
acres and contains about 16,000 cubic
yards of waste rock. The Ore Pad is
considered to be the most significant
source of groundwater contamination
and a major contributor to surface water
contamination;
• Mine OperationsArearThis area covers
about 5.2 acres and contains about
44,000 cubic yards of waste rock. The
PCB contamination and waste oil
contamination is also located in this area;
• WRP-3: This area covers about 6.6
acres and contains about 216,000
cubic yards of waste rock. WRP-3 is
the most significant source of surface
water contamination and also contributes
to sediment contamination; and
• Tailings Impoundment: The outside
footprint of the Tailings Impoundment
covers about 21 acres and contains
about 716,000 cubic yards of material.
The tailings are believed to be the most
significant source of sediment
contamination. Seepage from theTailings
Impoundment also contributes to surface
water contamination. The Tailings
Impoundment does not meet standard
criteria for long-term stability.
Sediment, including Salt Marsh
Two areas of sediment that contain high levels of
copper, lead, and zinc along with mine waste have
been targeted for cleanup.These areas are:
• Southern Goose Pond Mine Waste
Hot Spot: This 10-acre area within the
75-acre Goose Pond is adjacent to WRP-3
and the Tailings Impoundment. Mine
waste, particularly tailings, have
accumulated in the sediments in this area.
The Southern Goose Pond mine
waste hot spot was identified as an area
that represents an unacceptable threat
to ecological receptors.
• Salt Marsh Mine Waste Hot Spot:
Seven acres of salt marsh are co-
located within the Southern Goose Pond
mine waste hot spot. Similar to the
Southern Goose Pond mine waste hot
spot, this area was also contaminated as a
result of tailings deposition. The Salt
Marsh mine waste hot spot was identified
as an area that represents an unacceptable
threat to ecological receptors.
Two other areas of contamination that were
not evaluated for cleanup as part of the
remediation are 1.5 acres of Goose Cove and
3.6 acres of Dyer Cove that contain mine waste
in the sediment.This is because the HHRA and
BERA did not identify these areas as presenting
a significant threat to human health or the
environment. Removal of the mine waste from
these areas will be considered one of the
potential wetland mitigation measures that may
be performed as part of the cleanup.
Residential Use Area
This area of the Site extends along the access
road leading from the former Callahan Mine
property and is of concern because lead
and arsenic were found in the road bed and
residential yards exceeding levels acceptable
for long-term residential contact.
Cleanup Alternatives
Evaluated for the OU I
Remedial Action at the
Callahan Mine Site
EPA considers a full range of alternatives to
clean up a Super-fund site before selecting a
remedy. Many options are screened out early
in the process because site-specific conditions
render them ineffective and/or technically or
administratively infeasible.Others are eliminated
because they are cost prohibitive to implement.
For the Callahan Mine Site, alternatives that
require the off-site transport of the waste
rock, sediment, or tailings were eliminated due
to cost and community concerns. In addition,
the only approach that was retained for the
sediment cleanup was excavation or dredging
because the site conditions would not allow
for in-place capping or monitored natural
recover/The cleanup alternatives that survived
the initial screening were subject to a detailed
evaluation and comparative analysis in the
OU I Feasibility Study for the Callahan Mine
Site (OUI FS).These cleanup alternatives are
summarized below.
Alternative CMS I - No Action
Alternative CMS I ,the No Action alternative, was
retained as a baseline with which to compare
the other alternatives, as required by CERCLA.
This alternative does not include remedial
action components to reduce the contribution
of site source areas to groundwater, surface
water, or sediment contamination. No action
would be taken to reduce, control, or eliminate
direct exposure risks to residents of seasonal
properties along Old Mine Lane. No action
would be taken to reduce, eliminate, or control
risks to ecological receptors in Goose Pond or
salt marsh areas. No institutional controls would
be implemented to prohibit potable use of site
groundwater or residential development of
the Site.The only activity required by CERCLA
under this alternative is to assess site conditions
at least every five years.The estimated present
value cost of CMS I is $ 19,000.
Alternative CMS2 -
Capping of Tailings Impoundment; Off-
Site Disposal of PCB and Petroleum1
Contaminated Soil; Subaqueous
Disposal of Source Area Material
(from the Ore Pad, Mine Operations
Area, and WRP-3), Residential Use
Area Soil, and Sediment in a Confined
Aquatic Disposal (CAD) Cell in the
Former Mine Pit
Alternative CMS2 includes:constructing surface
water diversions to reduce the amount of
upslope runoff flowing onto and infiltrating
the Tailings Impoundment; installation of a
low-permeability cover system to contain and
isolate theTailings Impoundment; installation of
a horizontal drain to facilitate the dewatering
of theTailings Impoundment and the collection
and treatment of the discharge from the
horizontal drain in a constructed wetland;
subaqueous disposal of WRP-3, Ore Pad, and
Mine Operations Area source material, and
Residential Use Area soil exceeding preliminary
remediation goals (PRGs) in a CAD cell in
the former mine pit; and off-site disposal of
material contaminated with PCBs and waste
commingled with petroleum. It is possible that
additional measures, including a toe shear key
or buttress would be identified during design
as a necessary component to stabilize the
Tailings Impoundment. Alternative CMS2 also
includes the dredging and subaqueous disposal
of sediments exceeding PRGs in southern
Goose Pond and the adjacent salt marsh in a
CAD cell in the former mine pit Dyer Cove
and Goose Cove sediments that contain mine
waste may also be dredged and disposed in the
CAD cell in the former mine pit as part of Site
restoration and wetland mitigation activities.
Additional components include institutional
controls, environmental monitoring, and
five-year reviews to control potential human-
health and ecological risks due to exposure to
contaminated waste material.
The estimated present value cost of CMS2 is
$22.8 million. Figure 5 shows the major features
ofCMS2.
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Alternative CMS3 -
Capping of Tailings Impoundment; Off-
Site Disposal of PCB and Petroleum1
Contaminated Soil; Capping of Source
Area Material (from the Ore Pad,
Mine Operations Area, WRP-3), and
Residential Use Area Soil; and disposal
of Sediment in a Confined Aquatic
Disposal (CAD) Cell in the Former
Mine Pit
Alternative CMS3 includes: constructing surface
water diversions to reduce the amount of
upslope runoff flowing onto and infiltrating
the Tailings Impoundment; installation of a
low-permeability cover system to contain and
isolate theTailings Impoundment; installation of
a horizontal drain to facilitate the dewatering of
theTailings Impoundment and the collection and
treatment of the discharge from the horizontal
drain in a constructed wetland; disposal of
WRP-3, Ore Pad, and Mine Operations Area
source material, and Residential Use Area soil
exceeding PRGs into an on-Site waste cell that
would then have a low permeability cover system
installed over the waste; and off-site disposal of
material contaminated with PCBs and waste
commingled with petroleum. It is possible that
additional measures, including a toe shear key
or buttress would be identified during design as
a necessary component to stabilize theTailings
Impoundment.Alternative CMS3 also includes
the dredging and subaqueous disposal of
sediments exceeding PRGs in southern Goose
Pond and the adjacent salt marsh in a CAD
cell in the former mine pit. Dyer Cove and
Goose Cove sediments that contain mine
waste may also be dredged and disposed in the
CAD cell in the former mine pit as part of Site
restoration and wetland mitigation activities.
Additional components include institutional
controls, environmental monitoring, and five-
year reviews.
The estimated cost of CMS3 is $25.5 million.
Figure 6 shows the major features of CMS3
Cleanup Alternatives
Evaluated for the OU2
Remedial Action at the
Callahan Mine Site
The only alternative considered for the Early
Action for OU2 at the Callahan Mine Site was
institutional controls.This is a targeted cleanup
action to limit contact with contaminated soil
and prevent consumption of groundwater
' At the Callahan Mine Site, petroleum waste
is intermixed with contaminated mine waste.
Although CERCLA does not regulate petroleum
cleanups, the commingled contaminated material
containing CERCLA waste and petroleum waste will
be cleaned up as part of the proposed CERCLA
remedy.
within the former Callahan Mine property area
of the Site until the final OU2 cleanup decision
is proposed and selected.
The OLJ2 Early Action would involve the
placement of land use restrictions on the Site
property to prevent use of the groundwater or
future residential development within the former
Callahan Mine property area of the Site.
How Does EPA
Choose a Cleanup Plan?
EPA uses nine criteria to evaluate alternatives
and select a final cleanup plan (called a remedial
action) that will achieve the statutory goals of
protecting human health and the environment,
maintaining protection overtime and minimizing
contamination.These nine criteria make up the
assessment process used for all Superfund
sites.
Of these nine criteria, protection of human
health and the environment and compliance
with applicable or relevant and appropriate
requirements (ARARs) are considered threshold
criteria that must be met for a candidate cleanup
alternative to be selected.The next five criteria,
called balancing criteria, are used to evaluate and
compare the elements of the alternatives that
meet the threshold criteria. This comparison
evaluates which alternative provides the
best balance of trade-offs with respect to
the balancing criteria. State and community
acceptance are considered modifying criteria
factored into the final balancing of all criteria
to a selected remedy. Consideration of state
and community comments may prompt EPA
to modify aspects of the preferred alternative
or decide that another alternative provides a
more appropriate balance. These criteria are
as follows:
Threshold Criteria
I. Overall Protection of Human Health
and the Environment. Will the alternative
protect human health and plant and animal
life from the contamination released by the
Site? The chosen cleanup plan must meet this
criterion.
2. Compliance with applicable or relevant
and appropriate requirements (ARARs).
Does the alternative meet all pertinent
federal environmental and state environmental
and facility citing statues, regulations, and
requirements? Is a waiver required? The chosen
cleanup plan must meet this criterion.
Balancing Criteria
3. Long-term Effectiveness and
Permanence. How reliable will the alternative
be for long-term protection of human health
and the environment? Is contamination likely
to present a potential risk again?
4. Reduction ofToxicity, Mobility, orVolume
through Treatment. Does the alternative
incorporate treatment to reduce the harmful
effects of the contaminants, their ability to
spread, and the amount of contaminated
material present?
5. Short-term Effectiveness. How soon will
the risks be adequately reduced? Are there
short-term hazards to workers, the community,
or the environment that could occur during the
cleanup process?
6. Implementability. Is the alternative
technically and administratively feasible? Are the
materials and services needed to implement the
cleanup alternative (e.g. treatment machinery,
space at an approved disposal facility) readily
available?
7. Cost. What is the cost of constructing and
maintaining the cleanup alternative? Capital
costs and the present value of all costs over
the anticipated life of the cleanup alternative
are presented.
Modifying Criteria
8. State Acceptance. Does the State agree
with the recommendations? This criterion
considers the state's preferences among or
concerns about the alternatives, including
comments on ARARs or the proposed use of
waivers. This criterion is addressed following
state input on the FS and Proposed Plan.
9. Community Acceptance. What
suggestions or modifications do residents of the
community offer during the comment period?
What are their preferences and concerns about
the alternatives? This criterion is addressed
following community inputs on the FS and
Proposed Plan.
Comparative Analysis
of Alternatives
After completion of the detailed evaluation
of alternatives, a comparative analysis of
the alternatives is performed to identify the
alternatives that satisfies the two threshold
criteria of protection of human health and the
environment and compliance with ARARs.The
alternatives are then assessed to determine
which option is the best based on the five
balancing criteria. The alternative detailed
analysis and comparative analysis can be found
in Sections 4 and 5 of the Callahan Mine OUI
FS Report, which is part of the Administrative
Record.The comparative analysis from the OU I
FS is summarized below.
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Threshold Criteria
I. Overall Protection of Human Health
and the Environment.
Alternative CMS I, the No Action Alternative,
would not eliminate, reduce, or control source
areas or potential future exposure to contaminants
exceeding PRGs and would not meet the RAOs.
Therefore, it is not protective of human health
and the environment and cannot be chosen as a
final remedy.
Alternatives CMS2 and CMS3 would each be
protective of human health and the environment
Both alternatives would eliminate the direct contact
and incidental ingestion risks from PCBs, arsenic,
and lead within the OUI areas through removal
and/or capping of this material.The PCBs will be
taken to an appropriate off-site facility and the
arsenic and lead in the residential area will either
be disposed of in the CAD cell in the former mine
pit (CMS2) or capped on-site (CMS3).The removal
of the Ore Pad material will also control the most
significant source of groundwater contamination.
The removal of the Ore Pad, Mine Operations
Area,andWRP-3 and either its disposal in the CAD
cell (CMS2) or on-site capping (CMS3) will also
remove and/or control significant sources of surface
water contamination. Removal of WRP-3 and
capping/stabilization of the Tailings Impoundment
would prevent these areas from acting as a source
of sediment and surface water contamination.
Removal of the sediments that were found to be
acutely toxic and which also represent a food chain
threat and disposal into the CAD cell will eliminate
that threat to the site biota. Both alternatives would
implement institutional controls to prevent site use
that could damage the components of the cleanup
(particularly capped areas and the CAD cell).
Alternatives CMS2 and CMS3 are very similar
in the degree to which they achieve protection
of human health and the environment CMS2 is
more protective due to the greater long-term
effectiveness afforded by placement of the material
in the mine pit vs. reliance on an on-site cover
system.
Both alternatives are equal with regard to
protecting wetlands resources. As required by
federal Executive Order 11990, entitled "Protection
of Wetlands," through this Proposed Plan the
public is invited to comment on the EPA's plans to
protect wetland resources through the proposed
remedial action.
2. Compliance with ARARs.
Alternative CMS), No Action, would not comply
with ARARs, therefore, it cannot be chosen as a
final remedy.
Alternatives CMS2 and CMS3 would comply with
the ARARs identified in the OU I Feasibility Study.
In particular, they would comply with the State of
Maine mining rules and Clean Water Act As part
of complying with the Toxic Substances Control
Act and its regulations, this Proposed Plan includes
an EPA finding that the I ppm cleanup level for
PCBs selected for in the remedy will not pose
an unreasonable risk of injury to health or the
environment
Balancing Criteria
3. Long-term Effectiveness
and Permanence.
Alternative CMS I, No Action, would not achieve
this criterion since there would be no actions to
protect human health or the environment
Both alternatives CMS2 and CMS3 would provide
long-term effectiveness and permanence. Both rely
on the use of a cover system and stabilization of
theTailings Impoundment Given the large quantity
of material and the difficulty in relocating tailings,
this is the more effective and permanent approach
to achieve the RAOs and comply with ARARs
for the Tailings Impoundment With maintenance,
cover systems provide reliable long-term controls.
Both CMS2 and CMS3 remove the PCBs and
transport the material to an appropriate off-site
disposal location.This will be a long-term effective
and permanent solution to prevent future contact
with PCBs at the Site. Both CMS2 and CMS3
excavate the sediments that represent a threat
to site biota. Subaqueous containment of the
material in a CAD cell in the former mine pit will
provide a high degree of long-term effectiveness
and permanence.The material will be placed well
below the rim of the mine pit and at a depth such
that no disturbance of this material should occur
due to tidal action, even during storm events. No
maintenance beyond institutional controls to
prevent deep water activities or dredging of this
location would be necessary. CMS2 relies on this
same approach to control the source material at
WRP-3, Ore Pad, Mine OperationsAreas (excluding
PCBs and petroleum contaminated material
which will be disposed of off-site), and arsenic
and lead waste removed from the residential use
areas. CMS3 would place WRP-3, Ore Pad, Mine
OperationsAreas (excluding PCBs and petroleum
contaminated material which will be disposed of
off-site), and arsenic and lead waste removed from
the residential areas in an on-site cell and install a
cover system as the long-term control.While this
is an acceptable cleanup approach, the reliance on
the long-term maintenance and periodic repairs
to the cover system may result in a slightly lower
degree of long-term effectiveness and permanence
forCMS3.
CMS2, therefore, has a higher degree of long-term
effectiveness and permanence than either CMS3
or CMS I.
4. Reduction ofToxicity, Mobility, or
Volume through Treatment.
Alternative CMS I does not contain any components
to reduce the toxicity, mobility, or volume of
contaminants through treatment
Alternatives CMS2 and CMS3 rely on off-site
disposal rather than treatment for the principal
threat waste (PCBs) since the vast majority
of PCB contaminated material is below EPA's
guidance levels for treatment for PCBs and the
quantity of PCBs materials is too small to warrant
consideration of on-site treatment The major
components of CMS2 and CMS3 are source
control measures for large volumes of low level
threat wastes, which is consistent with EPA
guidance. In the event that the wetlands treatment
systems are installed, both CMS2 and CMS3 would
achieve some level of reduction in toxicity, mobility,
and volume through treatment as a result of the
sutfide reduction to immobilize the metals in the
treatment matrix
5. Short-term Effectiveness.
Alternative CMS I takes no actions so it does not
achieve the RAOs. It would, however, have the
lowest level of short-term impacts. Alternatives
CMS2 and CMS3 have short-term effects with
regard to the removal of the lead and arsenic
contamination in the residential use area. This
work would be scheduled to avoid periods when
the seasonal residents occupy these homes. The
homes themselves would not be altered by the
cleanup. For the common components of CMS2
and CMS3, there would also be similar short-term
impacts due to truck traffic transporting the PCB
and petroleum contaminated material off-site for
disposal and bringing the necessary materials to the
Site for the remediation activrties.There would also
be truck traffic associated with the importation of
the materials for the wetland treatment system
and, over the long-term, removal of contaminated
material from the treatment wetland systems.
The FS includes a remediation approach that
fully considered the community's concerns
regarding truck traffic. The cover systems would
be constructed using geosynthetic material, which
would require a relatively low volume of traffic,
along with the use of stone from an on-site quarry.
The use of on-site material eliminates several
thousand truck trips on local roads. In addition, the
fundamental approach to consolidate on-site under
a cap or CAD, eliminates tens of thousands of truck
trips that would be required on local road if the
waste material was transported off-site.
Both CMS2 and CMS3 would result in short-term
impacts to the wetland areas that are subject to
excavation. Some permanent loss of these areas
may occur to accommodate storm water control
structures and the wetland treatment system
associated with the cover system for theTailings
Impoundment The areas that are not subject to
permanent loss are expected to fully recover and
achieve a higher level of function and value post-
cleanup with the removal of the Site contaminants.
In addition, there will be a permanent loss of the
wedand areas that reside within the footprint of
theTailings Impoundment WRP-3, and the Mine
Operations Area. Some portion, and possibly all
of the wetland onWRP-l that contains the Stink
Cove sediments would also be lost, depending upon
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the amount of material from this area that may be
used for on-site restoration activities.There will be
short-term impacts to sub-tidal areas subject to
dredging or excavation. However, the permanent
removal of mine material from these areas will
create a long-term benefit to the environment.
Natural restoration is expected to occur relatively
quickly, in addition to any supplemental restoration
activity that may be implemented, such as die
establishment of eel-grass beds.
For CMS2 and CMS3,the time period to achieve
the RAOs will be shortThe RAOs will be achieved
once the source control and sediment activfties
are completed.
Overal I, C MS2 and C MS3 are equal in time needed
to achieve protection. CMS2 has a slightly lower
degree of short term impacts because CMS3
requires additional quantities of materials to
construct the second cover system.
6. ImplementabilitY
Alternative CMS I takes no action, other than five-
year reviews and therefore, would be technically
easy to implement Services and equipment are
available to implement Alternatives CMS2 and
CMS3. Construction of the cover systems would
require large volumes of soil/crushed stone which
is not currently available on site.On-stte quarrying
of non-suffide rock would be performed to obtain
material. None of these alternatives would interfere
with the ability to undertake additional remedial
actions.
The administrative feasibility of obtaining r^ulatory
approvals and the necessary permits for any
off-site actions is considered good to the extent
required for Alternatives CMS2 and CMS3. The
administrative process to obtain institutional
controls to protect the components of the remedy
(caps, treatment wetland, monitoring wells, the
CAD) also may be implemented for both CMS2
and CMS3. CM S2 an d CMS3 are eq ual wfth respect
to irnplementability.
7. Cost.
Of the two alternatives that would protect
human health and the environment and comply
with ARARs, CMS2 is the less expensive of the
alternatives that meet the threshold criteria.
Cost Category CMS I CMS2 CMS3
Capital Costs
(millions)
$0 $215 $24.1
Total Present $0.019 $22.8
Worth (30 yrs @ 7%)
{millions)
$25.5
Modifying Criteria
8. State Acceptance and
9. Community Acceptance.
ERfti an d Mai ne D EP have had substantive discuss ions
regarding the Site and the cleanup. EPA has received
input from the Maine DEP indicating that they are
supportive of the cleanup approach presented in
this proposed plan. Maine DEP supports CMS2 as
the Proposed Cleanup Option.
Community acceptance will be evaluated based on
the feedback received during the comment period.
EFA has worked closely with the community during
the entire Rl/FS. Numerous public meetings and fact
sheets have been released to provide the public
with a solid understanding of the Site conditions.
The cleanup alternatives reflect the community
input. In particular, significant efforts were made to
identify cleanup approaches that would minimize
truck traffic.
Public Notice of Determination that
the PCB Cleanup Level is Protective of
Human Health
EPA has made a finding under theToxic Substances
Control Act (TSCA) PCB Regulations at 40 CFR
Part 761, that the cleanup level of I ppm established
for PCBsatthis Site will not pose an unreasonable
risk of injury to health or the environment.
Public Notice of Unavoidable Impacts
to Wetlands and Aquatic Resources
EPA is seeking public comment
on the following:
In accordance with federal Executive Order
11990, entitled "Protection ofWetlands," EPA has
determined that there may be unavoidable adverse
impacts to wetiands and aquatic resources. To
the extent that federally regulated wetlands and
aquatic resources are located within and adjacent
to the Ore Pad, Mine Operations Area, Waste
Rock Pile-3, or the Tailings Impoundment, the
contaminated portions of Goose Pond and the
adjacent Salt Marsh may be removed and/or altered
as part of the cleanup actions,Wherever possible,
wedand areas will be restored, EPA has evaluated
the requirements of the applicable regulations,
including Section 404 of the Clean Water Act
and identified die proposed actions as the least
damaging practicable alternatives to protect
federally regulated wetland and aquatic resources
from exposure to contaminated sediments and
contaminated surface water,These wetland areas
at the Site are shown in Rgure 7. As part of the
remedial desjpi process, EPA will consider whether,
as mitigation for Site wedand alterations, EPA will
dredge approximately 1.5 acres of Goose Cove and
3.6 acres of Dyer Cove to remove mine wastes that
had been historically disposed of into these water-
bodies. The dredged mine waste will be disposed
of in die CAD cell.
Why Does EPA Recommend
the Preferred Cleanup
Alternatives Identified in
this Proposed Cleanup Plan?
EPA recommends the preferred cleanup alternative
presented below in this proposed cleanup
plan as the best balance of the criteria used to
evaluate various alternatives. This alternative is
recommended because it is protective of human
health and the environment, while at the same time
being the most cost effective way to achieve the
RAOs,The cleanup being proposed provides: both
short-term and long-term protection of human
health and the environment; attains all Federal
and State applicable or relevant and appropriate
requirements; utilizes permanent solutions to
the maximum extent practicable by eliminating
the most significant sources of surface water,
groundwater, and sediment contamination and
eliminates human contact with PCBs on site, as well
as lead, and arsenic in the OUI areas. In addition,
EPA has taken into consideration the input from
the local community in developing the cleanup
plan. The proposed cleanup approach targets the
use of on-site material to minimize local truck
traffic and reduce carbon emissions.The proposed
cleanup approach also allows for further studies
to determine if natural processes will result in the
cleanup of the portions of the Site outside the
OUI cleanup area.Thisincludes:65 of the 75 acres
of Goose Pond; 35 acres of the former Callahan
Mine property and 16 acres of Saft Marsh. This
phased cleanup approach targets the major threats
to human heakh and the environment.
A Closer Look at EPA's Cleanup
Proposal
EPA has selected a cleanup plan for OU I at the
Callahan Mine Site to protect human health and
the environment The cleanup pbn is summarized
below and presented in detail in the FS:
Alternative CMS2 - Capping ofTailings
Impoundment; Off-Site Disposal of
PCB and Petroleum Contaminated
Soil; Subaqueous Disposal of Source
Area Material (from the Ore Pad,
Mine Operations Area, and WRP-
3), Residential Use Area Soil, and
Sediment in a Confined Aquatic
Disposal (CAD) cell in the Former
Mine Pit
This alternative would consist of the following key
components:
• Pre-design Investigations and Studies;
• Tailings Impoundment Cover System with
stabilization measures, possibly including a
toe shear key or buttress;
• Horizontal drain wrthinlailinjp Impoundment
and passive treatment of the discharge from
the horizontal drain in a constructed
wetland; 7
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• Excavation and subaqueous disposal of
WRP-3,Ore Pad.and Mine OperationsArea
source material in the CAD cell in the
former mine pit;
• Excavation of soil containing arsenic and lead
above the cleanup levels in the Residential
Use Area of the Site and subaqueous
disposal in the CAD cell in the former mine
pit;
• Excavation and off-site disposal of PCB-
contaminated soil exceeding PRGs;
• Excavation and off-site disposal of petroleum-
contaminated soil commingled with
CERCLA waste;
• Dredging of Goose Pond and salt marsh
sediment exceeding PRGs and subaqueous
disposal in the CAD cell in the former mine
pit;
• Establishment of institutional controls
to protect the components of the
remedy (including caps, treatment
wetlands, monitoring well, and the CAD
cell)
• Wetland restoration and mitigation,
which may include dredging and
subaqueous disposal in the CAD cell of
mine waste located in Goose Cove and
Dyer Cove;
• Installation of monitoring wells;
• Long-term operation and maintenance;
and monitoring, including institutional
control inspections; and
• Five-year reviews.
Figure 5 is an alternative remedy map showing
the major components of this alternative.
Pre-design Investigations
and Studies
A series of pre-design studies would be
performed to support the design of the
Remedial Action. Examples of pre-design that
may be performed are listed below:
• Topographic survey;
• Pre-excavation sampling to refine
estimates of the extent of PCB
contamination at the Mine Operations
area;
• Pre-dredge sampling to refine estimates
of the extent of sediment contamination
exceeding PRGs;
• Pre-excavation sampling to refine
estimates of the extent of petroleum
contamination at the Mine Operations
area;
• Geotechnical pre-design investigation(s);
• Borings within theTailings Impoundment
to characterize physical properties and
spatial variability of tailings in cut/fill areas
(excavations, construction traffic,
settlement, dewatering, etc.);
• Borings along and adjacent to the toe of
the Tailings Impoundment berm to
characterize physical properties and
spatial variability of estuarine deposits
and native clay soils (long-term and short-
term global stability evaluations, design
of toe improvements, etc.);
• Borings along and adjacent to the toe
of WRP-3 to characterize estuarine
deposits and native clay soils (short-term
global stability evaluation, construction-
related issues, etc.);
• Bench scale and pilot scale testing of the
wetland treatment system; and
• An assessment of wetland mitigation
requirements and design options.
Tailings Impoundment Cover System
and Stabilization Measures
Alternative CMS2 would include regrading the
tailings surface and berm to reduce modeled
instability beneath and immediately behind the
berm that could contribute to berm failure,
and installing a low-permeability cover system.
Additional measures, including a shear key
or buttress could be included if determined
necessary during the design.The cover system
would include surface water diversions along
its western edge to reduce the amount of
upslope runoff potentially infiltrating under
the edge of the cover system and infiltrating
theTailings Impoundment.The existing access
road along the toe of the tailings impoundment
berm would be retained and connected with
the WRP-3 Haul Road after removal ofWRP-
3 to provide construction, maintenance, and
long-term inspection/monitoring access to the
area along the toe of the tailings impoundment
berm.
The re-contoured surface would be capped with
a low-permeability cover system to minimize
infiltration/recharge and prevent human and
ecological receptor contact with exposed
tailings. The cover system is shown on Figure
8 and would consist of, from bottom to top: a
cushion layer of regraded tailings or /2-inch or
less of crushed stone;a40-mil geomembrane;a
geocomposite drainage layer; and approximately
15 inches of crushed stone.The design, however,
would determine the actual thickness of the
membrane most appropriate for a stone cover
and whether a geosynthetic cushion would
be needed to protect the geomembrane.The
crushed stone would be obtained on-site by
quarrying rock from the area west of the Ore
Pad Haul Road and crushing it. This on-site
quarrying and crushing approach was chosen
to minimize the amount of heavy-truck traffic
bringing material onto the site over the narrow
and twisting local roads.The estimated volume
of required crushed stone is 53,400 cubic yards.
Therefore, on-site quarrying would eliminate
the equivalent of 3,814 truck loads of material A
vegetative layer on the cover system is not being
proposed in order to eliminate truck traffic
needed to import large volumes of soil/loam.
With a low-permeability cover to reduce
infiltration, the seepage of contaminated
groundwater along the toe of the Tailings
Impoundment berm is expected to decrease as
groundwater within the Tailings Impoundment
slowly drains.To further reduce adverse impacts
on Goose Pond surface water and salt marsh
areas, a horizontal drain would be installed,
running south to north, within the tailings just
above the clay/till layer, and near the eastern
edge of the Tailings Impoundment to capture
water draining from the tailings. The drain
would provide several benefits compared to
the capture of surface water in the ditch at
the toe of the berm: reducing the estimated
time needed to dewater near the Tailings
Impoundment by about a third; improving
capture of tailings drainage and reducing capture
of run-off; and the amount of water requiring
subsequent treatment.
A passive treatment system using an anaerobic
wetlands system would be used to treat the
water from the horizontal drain and a pilot-
scale treatability test would be implemented.
Up to approximately I acre appears available
northeast of the Tailings Impoundment, while
perhaps two acres are available within the
property boundary at the southeast corner,
for the placement of the wetland treatment
system and storm water basins. Use of either
area would require clearing and excavating of
land, some of which is existing wetland.
Excavation and Disposal of WRP-3,
Ore Pad, and Mine Ops Area Source
Material in a CAD Cell in the Former
Mine Pit
Source material for groundwater contamination
and surface runoff contamination with metals at
WRP-3 (including portions of the WRP-3 Haul
Road), Ore Pad, and Mine Operations Area
would be excavated and subject to subaqueous
disposal in a CAD cell in the former mine pit.
Horizontal boundaries for the excavation would
be delineated based on interpretation of Rl data
as to the areas with the greatest potential to
contribute to groundwater and surface water
contamination. In addition, a 200-foot-wide
strip at the western edge of WRP-2 between
the Ore Pad and the Mine Operations Area
would also be excavated. The vertical limit of
excavation would be based on the PRGs for
cleanup of the recreational areas. These PRGs
have been chosen with the goal that these
areas would not require further remediation
under OU 2. Excavation would be performed
with conventional earth moving equipment.
Excavated material would most likely be
transported to the mine pit by a combination of
trucks and a floating conveyor system to deliver
material to the approximate center of the pit. If
fill material is needed as subgrade material for
the Tailings Impoundment cap, some material
designated for disposal in the mine pit may be
used under the cap.
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Excavation of Residential Use Area
Surface Soil and Disposal in a CAD
Cell in the Former Mine Pit
Surface soil exceeding the PRGs (see Table
2) at residential lots along Old Mine Lane
would be excavated to a depth at which PRG
exceedances no longer occur, and disposal in a
CAD cell in the former mine pit. If fill material
is needed under the Tailings Impoundment cap,
some material designated for disposal in the
mine pit may be used under the cap. At the
completion of the remediation the area will be
available for unrestricted residential use based
on the lack of any CERCLA risk from either
soil or groundwater contamination.
Excavation and Off-Site Disposal of
PCB-Contaminated Soil
Soil with PCBs exceeding a concentration of
I ppm would be excavated and segregated
in temporary stockpiles for testing prior to
disposal. Current estimates are that up to 2,197
cubic yards of soil would exceed I ppm PCBs.
An estimated 220 cubic yards of soil would
exceed 50 ppm. Excavated material with PCBs
concentrations equal to or greater than 50
ppm would be disposed of in a hazardous waste
landfill permitted for PCB disposal (or at a PCB
disposal facility approved under 40 CFR Part
761). Excavated material with concentrations
above I ppm but less than 50 ppm would be
disposed of at an appropriate off-site facility.
Dredging of Sediment Hot Spots
in Southern Goose Pond and the
Adjacent Salt Marsh Sediment and
Disposal in a CAD Cell in the
Former Mine Pit
The sediments exceeding the PRGs in Table 3
that are located in Southern Goose Pond and
Salt Marsh would be dredged and disposed
in the CAD cell in the former mine pit. Dyer
Cove and Goose Cove sediments may also be
dredged and disposed in the CAD cell in the
former mine pit as part of wetland mitigation
activities. The OUI FS assumed the use of a
hydraulic dredge that pumps dredged material
directly to the mine pit through high-density
polyethylene piping. This would eliminate the
need for on-shore handling, dewatering, and
the construction of an upland confined disposal
facility.A drop tube would be used to lower the
actual discharge point and reduce entrainment
of material in the upper portion of the water
column. Silt curtains would be placed around
the mine pit to reduce the potential for turbid
water to migrate to other areas of Goose
Pond. Proper selection and operation of dredge
equipment along with water quality monitoring
will help minimize migration of suspended
material from the dredge site. In addition, silt
curtains will be used as appropriate to minimize
migration of suspended material from the area
being dredged.
Dredged material will be placed below the
mixing boundary in the former mine pit to
prevent long-term contamination of surface
water in the remainder of Goose Pond.
Information gathered during the Rl identified
a mixing boundary within the 300-foot deep
mine pit about 30 feet below mean sea level.
Water below this boundary does not mix
with the upper waters of Goose Pond. Source
material placed below this boundary would
not be expected to contaminate surface water
in the remainder of Goose Pond.The available
data indicate that the mine pit can hold up to
1,300,000 cubic yards of source material and
dredged sediment without filling above the
mixing boundary. This is more than adequate
to hold the estimated 101,000 cubic yards of
sediment and 347,000 cubic yards of source
material and soil identified for disposal in the
former mine pit.This volume would only fill the
pit to an estimated depth of 120 feet below
sea level.The estimated level of fill in the mine
pit after implementation of CMS2 is shown in
Figure 8.
Backfilling of dredged areas in Goose Pond
is not planned. This is primarily because the
mine waste has artificially filled Goose Pond
and removal would partially re-establish the
pre-mine hydrology.The salt marsh, excavated
or disturbed during remedial activities, would
be restored and any permanent loss of area
or function would be included in the wetland
mitigation component of the cleanup.
Wetland Mitigation
Implementation of Alternative CMS2 would
result in alteration of upland Wetlands B, C, D,
and E; coastal; and subtidal wetlands.The levels
of compensatory wetland mitigation will be
established during the design. One mitigation
concept is to remove the mine waste deposits
from Goose Cove and Dyer Cove and place
that material in the CAD cell in the former
mine pit to allow these areas to be restored
to depth and habitat type comparable to pre-
mining conditions. Removal of this material
would also reduce the contaminant levels in
those areas.
Institutional Controls
As part of this alternative, institutional
controls would be implemented to prevent
any disturbance of the Tailings Impoundment
cover system or the CAD cell in the former
mine pit.
Long-Term Operation,
Maintenance, and Monitoring
Anticipated maintenance activities would
be expected to include: maintenance of the
low-permeability cover system at the Tailings
Impoundment; maintenance of storm water
diversions and drainage structures to prevent/
repair erosion damage; possible removal
of contaminated media and the addition of
clean to the treatment wetland; possible
repair of reconstructed salt marsh, and repair/
replacement of damaged monitoring wells. A
long-term monitoring plan would be developed
to evaluate the success of the cleanup actions.
This plan would include groundwater, surface
water, sediment, and biota monitoring and
would also collect data to support the Five-Year
Reviews. Inspections of the Site and verification
that the proper notices and restrictions are in
place at the local governmental offices would
also be included to verify that the institutional
controls have not been violated.
Five-Year Reviews
Under CERCLA§ 121 (c), 42USC §9621 (c), any
remedial action that results in contaminants
remaining on-site at concentrations above those
allowing unlimited exposure and unrestricted
use must be reviewed at least once every five
years. Five-year reviews will be performed to
determine whether the implemented OU I
remedy continues to be protective of human
health and the environment, or whether the
implementation of additional remedial action
is appropriate.
Summary of cost
The present worth for Alternative CMS2, based
on a 7 percent discount rate and a 30-year
duration, is estimated to be $22,839,800.
OU 2 Early Cleanup Action
EPA has identified the need for an Early
Action for the OU2 area. Specifically, since the
finalization of the OU2 RI/FS and selection of
an OU2 cleanup action is dependent upon the
completion of the OUI Remedial Action, many
years will pass before an OU2 cleanup can be
implemented. The Callahan Mine Superfund
Site Human Health Risk Assessment identified
the future consumption of contaminated
groundwater and the direct contact with lead
and arsenic contaminated soil in a residential
setting as potential threats to human health.To
address this threat to human health, EPA will
implement an early cleanup action to prevent
residential development or groundwater use
within the former Callahan Mine portion of
the Site.
The Remedial Action Objectives for the early
cleanup action are:
• Prevent exposure to soil or waste with
concentrations of lead or arsenic above
the Site specific cleanup levels for future
residential use within the former Callahan
Mine portion of the Site; and
• Prevent ingestion of bedrock groundwater
in excess of federal safe drinking water
act Maximum Contaminant Levels
(MCLs); Maximum Contaminant Level
Goals (MCLGs); State of Maine Maximum
Exposure Guidelines; or EPA risk
standards within the former Callahan
Mine portion of the Site.
The design for the early cleanup action will identify
the extent of the former Callahan Mine portion
of the Site that exceeds the residential PRGs for
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arsenic and lead developed for the OUI cleanup
and the extent of groundwater that exceeds MCL&
MCLGs, MEGs, or risk based standards in the
absence of these. Figure 4 shews the extent of the
area of the former Callahan Mine portion of the
Site that would be subject to institutional controls
using the existing Site data.
The early cleanup action will include the placement
of land use restrictions that run with die land
to effectively prevent future residential use or
installation of water supply wells within die former
Callahan Mine portion of the Site. Restrictive
covenants are the primary mechanism to achieve
this objective with local and/or state ordinances or
zoning to supplement the property restriction.
Because the only RAOs are to prevent the use of
the Site and not restore groundwater or contain/
remove contaminated soil, no other technologies
or alternatives were considered, other than No
Action. The OU2 Feasibility Study will develop
and analyze technologies with respect to any
groundwater restoration,migration control,orsoil
remediation^ very simplified nine criteria analysis
was performed in Section 6 of the OU I FS for
No Action and Institutional Controls for an earty
cleanup action for OU2.
EPA has determined that a cleanup action is
appropriate for OU2 at the Callahan Mine
Superfund Site.The Early Action provides the best
balance of the NCR criteria to ensure protection
of human health prior to the implementation of
the OU2 response action.The Earty Action may
be the only remedial action for OU2 or may be
the first component of additional remedial actions
that will be evaluated in the OU2 Feasibility Study
and selected in a future OU2 ROD.
How You Can Comment
On EPA's Cleanup Proposal?
To provide an opportunity for public input on
the OUI Proposed Plan, EPA will hold a 30-day
public comment period, from July 10, 2009 to
August 10,2009. EPA will hold an informational
meeting on July 9,2009 prior to the start of the
public comment period. EPA will accept formal
written comments and hold a public hearing
on August 6, 2009. EPA uses this public input
to improve the cleanup proposal.Your formal
input and ideas will become part of the official
public record.The transcript of comments and
EPA's written responses will be documented in
a Responsiveness Summary when EPA releases
the final cleanup decision.
There are three different ways in which
individuals can express their comments on this
Proposed Plan:
Comments can be submitted in
writing to EPA by August 10,2009 to:
Edward Hathaway, RPM
U.S. EPA Region I
I Congress Street, Suite I 100 (HBT)
Boston, MA 02II4-2023
Comments can be sent to the EPA
RPM by email at: hathaway.ed@epa.gov by
August 10,2009.
Comments can be spoken into the
official public record during the public
hearing on August 6,2009.
EPA encourages anyone with a concern or who
favors the cleanup plan.to express their opinion
during the comment period. All comments are
welcome. Any of the three mechanisms above
are acceptable for providing comments and all
of the comments are given equal weight.
Two types of public meetings will occur with
respect to the OUI Proposed Plan.The first
will be an informational meeting to explain
the proposed OUI cleanup and answer any
questions that may arise.This meeting will focus
on a discussion of the OU I Proposed Plan
and RI/FS and is considered informational only.
Comments that are made during this meeting
will not be part of the "official record." The
second type of meeting, a public hearing, will
occur during the official comment period-Atthis
meeting, EPA will provide a brief summary of the
cleanup proposal and then the floor will be open
for spoken comments.A stenographer will be
present to record all of the comments offered
during this comment session.Comments made
must be limited in duration in order to allow
all individuals present to have an opportunity
to speak their comments into the record. EPA
does not respond to any of the comments made
at the public hearing other than to indicate the
time limits or request clarification.At the close
of the formal comment session, if time permits,
EPA will be available to answer questions.
Although EPA's Early Action for OU2 is not a final
agency remedial action subject to formal public
comment, any feedback the public wishes to
provide on the proposed early action during the
OUI public comment period will be accepted
and will be considered before a final decision
on implementing the proposed early action for
OU2 is made.The comment period will last for
thirty days unless an extension is requested,
EPA will typically allow a thirty day extension,
if requested. Once the comment period has
ended, EPA will assemble and evaluate all of the
submitted comments. Appropriate revisions to
the final selected OU I remedy Plan will be made
based on these comments. EPA will then sign
the OUI Record of Decision (ROD) describing
the chosen cleanup plan.The OUI ROD and a
summary of responses to public comments will
be made available to the public at the public
repositories. The final decision on the OU2
Early Action, including any responses to public
comments, will also be made available at the
public repositories.
For More Information
about the Cleanup:
The Administrative Record is a collection
of documents generated during the
investigation of the Callahan Mine Site
that form the basis for selection of the
cleanup action.The Administrative Record
can be found at the following locations:
EPA Records Center
I Congress Street, Suite 1100,
Boston, MA 02114-2023
(617)918-1453
Hours:
10:00 a.m.-noon. 2:00 p.m.-5:00 p.m.
Brooksville Public Library
I Town House Road,
Brooksville, ME 04617
(207) 326-4560
Hours:
Monday and Wednesday:
9 a.m. to 5p.m.
Thursday Evening: 6 p.m. to 8 p.m.
Saturday: 9 a.m. to 12 noon
Additional information about the Callahan
Mine Site is also available on the EPA
New England website: www.epa.gov/ne/
superfund/sites/callahan
(type Callahan Mine into the search box).
If you have any questions
about the Callahan Mine
Site, please contact:
Ed Hathaway
EPA Remedial Project Manager
617-918-1372
hathaway.ed@epa.gov; or
Pam Harting-Barrat
EPA Community Involvement
617-918-1318
harting-barrat.pamela@epa.gov
10
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r
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', / "* : i
fi*. u r /•
^•• -
T 2J Q€G scalr distal Inpographic map
obtained -tram Maine Office
Figure 1
Site and Study Areas
Callahan Mine Superfund Site
BrooksviJle, Maine
MACTEC. Inc.
-------
I
biLJI
Figure 2
Historical Mine Features (1972)
-------
PCB Contaminated
Area of Petroleum
ContaninaUd S-:>il
Failirg- Iw'^taid C f
OU1 Remediaoon Areas:
["_7J Ore Pad
! I Mine Opefafioiis Area
_ »_I Tailings I mpaundment
^H Goose "•:" a and Goose Cove Sediment
. J G«JS9 Penti Salt .Marsh
ock Pile 3
Figure 3
OU1 Remediation Areas
Legend
Batfivmetrlc Contour
-------
a " =2
-------
Confined Aquae
l inAR) Toll
j Quarry .a/ea
for Constructicr
Material
Stink Cove
Segment to
VUetland Restofatior
s of Readlj
' Af^oa i ant Har m
Goose Pond
Salt Marsh
apTamnjs VMIandC
nl M .
I I '.'me OpefatiofiaAiea
I JQr^
I I failings I
I I Waste RKk Pile 3
I I Trsdenlial Use Are
I I roosc Po
Figures
Alternative CMS2
Legend
Balhvmefrii" Contour
-------
Goosa Cove
Sediment
Confined Aquatic
l (HAH) Tell I.
ntial Us*
| Area of Site
ir'.vr'.^i L''^-?n1j on Bo sin , —r—^
and Treattnant Wetland \
Goose Pood
Salt Muf.il i
• _ : :- - • ( - .. ,1 • l
CJU1 -ie mediation Areas:
I I
I I railings ImpoundmeH
I IWas1eRockPile3
I I Residential Us« Area
I I I'cors F'ono iedinrft
I 1 ;;c.?rc Pone Salt Ma-=h
.x'^fcmtHcgt /
f • '. ,' 1
Legend
Rathvm*1rir Hnnlniir
Figure 6
Alternative CM S3
-------
Wetland E
i Stats Juri*dirti«i
Special SignllcancBj
Extant
Permanent Impact torn
DMtnlion Basin
aitd Treatment 'jVetland
Figure?
Alternative CMS2
-------
°r
-10
-50
-100
-150
-200
-250
-3DO1-
ALTERNATIVE CMS2 THICKNESS OF F1LL
-IN PIT APPROXIMATELY ISO FT. DEPTH
BELOW MSL APPROXIMATELY 120 FT.
ALTERNATIVE CMS3 THICKNESS OF RU-
IN PfT APPROXIMATELY 70 FT. DEPTH
BELOW MSL APPROXIMATELY 230 FT.
MIXING DEPTH IN GOOSE POND
-60 MSL 982.000 CY
-80 MSL 777,000 CY
-100 MSL 608,000 CY
-120 MSL 471.000 CY
BEDROCK
BEDROCK
WEST TO EAST CROSS-SECTION THROUGH MINE PIT
40 80
9_E
SCALE IN FEET
160
27" TOTAL DEPTH
(FINAL THICKNESSES OF
STONE. GEOSYNTHETICS,
AND CUSHION LAYER
WILL BE IDENTIFIED
DURING DESIGN.)
TAILINGS
FINAL GRADE
DRAINAGE GEOCOMPOSITE
40-MIL LLDPE GEOMEMBRANE
15" PROTECTION LAYER
(CRUSHED STONE DH=6")
12" CUSHION LAYER
-(CRUSHED STONE, OR
TAILINGS. IF SUITABLE)
SUBGRADE
INFILTRATION BARRIER CAP
NTS
DEL 061 MS
CALLAHAN MINE SUPERFUND SITE
BROOKSVILLE. MAINE
JTMACTEC
CAD CELL AND TAILINGS IMPOUNDMENT
COVER SYSTEM
Project 3612-06-2047.30
Figure 8
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vvEPA
Protection U.S. Environmental Protection Agency (EPA)
Agency
Callahan Mine Superfund Site
Brooksville, ME
You are Invited to Attend!
Public Information Meeting
July 9,2009
7:00 p.m.
Brooksville Town Office,
I Town House Road
Brooksville, ME
Public Hearing
August 6,2009
7:00 p.m.
Brooksville Town Office,
I Town House Road
Brooksville, ME
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