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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                      obtained -tram Maine Office
                                                                             Figure 1
                                                                 Site and Study Areas
                                                              Callahan Mine Superfund Site
                                                                         BrooksviJle, Maine
                                                              	MACTEC. Inc.

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        I
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                                  Figure 2
                      Historical Mine Features (1972)

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                    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

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           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

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                                   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

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             Wetland E
          i Stats Juri*dirti«i
         Special SignllcancBj
           Extant 
                                                                           Permanent Impact torn
                                                                                   DMtnlion Basin
                                                                           aitd Treatment 'jVetland
                                                                                                               Figure?
                                                                                                     Alternative CMS2

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   °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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