| Site Type: Long Term/National Priorities List (NPL) |
CALLAHAN MINING CORP
Map this site in Cleanups in My Community
| Brooksville (Cape Rosier),  Maine|
| Hancock County
| Street Address: ||Haborside |
| Zip Code: || 04617 |
| Congressional |
| EPA ID #: ||MED980524128 |
| Site ID #: ||0101028 |
| Site Aliases: |
| Site Responsibility: ||Federal, Potentially Responsible Parties |
| NPL LISTING HISTORY |
| Proposed Date ||09/13/2001|
| Final Date ||09/05/2002 |
The Callahan Mine site is located approximately 1,000 feet east-southeast of Harborside Village in the Town of Brooksville, Hancock County, Maine. The site is the former location of a zinc/copper open-pit mine. The mining operations were conducted adjacent to and beneath Goose Pond, a tidal estuary. The Callahan Mine was reputedly the only intertidal heavy metal mine in the world at the time of its operation. The property comprises 150 acres and is located in a coastal, rural setting on the Cape Rosier peninsula. The property abuts Goose Pond to the east, and private properties to the west, south, and north. Facility features include large waste piles (waste rock piles), a tailings pond, and mine operations buildings and structures. The open pit mine ceased operations in 1972 and was flooded by opening a dam at Goose Falls. The mine is currently under water and is subject to daily tidal exchange in Goose Pond. Goose Pond is connected to Goose Cove to the north by a reversing falls known as Goose Falls. Goose Cove is located on the southern part of Penobscot Bay.
The zinc/copper sulfide deposit was discovered in 1880 at low tide by a clam digger. The main components of this deposit were sphalerite and chalcopyrite, accompanied by abundant pyrite and lesser amounts of pyrrhotite. The first mine operated until 1887. Ore was mined from three shafts. Efforts were made to mine the ore sporadically through 1964. Callahan Mining Corporation geologists became interested in the potential of the property in 1964 and subsequently open pit mining operations commenced in 1968. Two dams were constructed at the saltwater inlet and freshwater inlet of Goose Pond. Fresh water that normally flowed into Goose Pond was diverted south to Wier Cove via a drainage ditch. Goose Pond was subsequently drained to allow for the excavation of the mine.
The open-pit mine was approximately 600 to 1,000 feet in diameter and 320 feet deep. Approximately 5 million tons of non-ore-bearing waste rock and 798,000 to 800,000 tons of ore-bearing rock were removed from the mine. Waste rock was removed and piled throughout the property, but predominantly in an area south of Dyer Cove. This area has been referred to as "Callahan Mountain," due to the large volume of waste rock located in this area. In addition, a large amount of marine clay (200,000 to 225,000 tons) was dumped on the lower portions of "Callahan Mountain" after a mud slide occurred at the open-pit mine. Dyer Cove, currently a small part of the Goose Pond estuary, was a fully enclosed area used to temporarily store water pumped from the open pit mine. Particulates were allowed to settle out prior to pumping the water from this cove to Goose Cove. Sediment-laden water from the mine was also pumped through a 16-inch pipe line, discharging directly into Goose Cove, north of Goose Pond.
Ore was trucked from the mine to an ore storage area. From here, the ore was loaded into a series of crushers and mills that reduced the rock to the consistency of fine sand and silt. The small particles containing zinc and copper were then recovered by a process called "flotation." The ore was passed through flotation cells into which chemicals were introduced that caused the minerals to float on bubbles. Chemicals that were used in the flotation process included dithiophosphate salts, aryl phophorodithioate, cyclohexanol, and cresol. The flotation process creates a "froth" which lifts (through surface tension) the mineral particles and depresses or allows the remaining rock to sink. The mineral rich froth was collected, washed, dried, and stockpiled in a portion of the mill where it awaited transportation to a smelter. The average ore grade was 1.30% copper, 4.91% zinc, 0.35% lead, and 0.50 ounces per ton of silver.
The remaining non-mineral particles and residues of the chemical reagents were discharged to the tailings pond. The approximately 11-acre tailings pond is located in the southern portion of the property, adjacent to Goose Pond. A series of dams were constructed as material was added to the tailings pond. The final height of the dam is 82 feet. Mining operations ceased in June 1972 due to the depletion of the mineral reserve. Milling ceased in July 1972.
Threats and Contaminants
A study completed by the Maine Department of Marine Resources in 1975 examined bioaccumulation of trace elements in selected marine organisms located in Goose Cove. Levels of cadmium, copper, lead, and zinc were detected at several times to several orders of magnitude higher, in Goose Cove biota and sediments than in samples collected from other Maine midcoastal and river locations. The most recent sampling event was conducted by the Maine Department of Environmental Protection in October 1999. Soil samples, tailings pond samples, tailings pile samples, waste rock pile samples, sediment samples, and surface water samples were collected. Soil samples were collected from the mine entrance and the mine operations areas. Sediment samples were collected from Goose Pond, Dyer Cove, and Horseshoe Cove. Samples were submitted to the State of Maine Health and Environmental Testing Laboratory for metals analysis. The analytical results for these samples are used to associate hazardous substances with the sources and attribute hazardous substances to the site.
EPA completed a Human Health and Ecological Risk Assessment for Operable Unit 1. EPA has identified current and future potential threats to human health and the environment at the Callahan Mine Site. A detailed summary of the threats can be found in the OU1 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:
EPA has identified the above conditions as an unacceptable threat to human health and the environment. The OU1 Feasibility Study was developed to identify cleanup options to protect human health and 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 organisms; and
- Water discharging from the waste areas (seeps), particularly WRP-3, significantly exceeds levels that could adversely impact aquatic organisms.
For the Callahan Mine Site, EPA will be implementing the cleanup in three phases (know as operable units). Operable Unit 1 (OU1), which was described in the September 2009 Record of Decision, will target the following threats to human health and the environment:
- Soil and waste contaminated with PCBs; and
- Soil and waste contaminated with lead and arsenic in areas with current residential use.
Operable Unit 3, which as also described in the September 2009 Record of Decision, will target the following threats to human health and the environment:
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 groundwater 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:
- Soil and waste that represent the most significant threat to surface water, sediments, and groundwater (specifically Waste Rock Pile 3, Ore Pad, and Mine Operations Area);
- Areas of sediment that were shown to be acutely toxic and represent a food chain threat; and
The remaining components of OU2 will address site wide groundwater contamination and site wide soil contamination. OU2 will also evaluate the success of OU1 to determine whether any additional actions are necessary to achieve the cleanup objectives for surface water and sediment. A supplemental RI Report and revised Human Health Risk Assessment (HHRA) and Baseline Ecological Risk Assessment (BERA) reports may be developed for OU2.
In July 2009, EPA proposed the following cleanup action, known as Alternative CMS2, for Operable Unit 1 (OU1) and an early action for Operable Unit 2 (OU2).
- Prevent the installation of water supply wells; and
- Prevent residential development.
On September 30, 2009 EPA selected the following cleanup action, known as Alternative CMS2, for Operable Unit 1 (OU1) and an early action for Operable Unit 2 (OU2). The selected remedy for OU1 at the Callahan Mine Superfund Site was identified as Alternative CMS2 in the OU1 Feasibility Study and in the Proposed Plan. The selected remedy for OU1 includes the following major components:
- Performance of pre-design investigations and studies;
- Construction of 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 the Tailings Impoundment (cover material to be quarried from on-site);
- Installation of a horizontal drain, or other drainage methods (e.g., vertical wells or drains), to facilitate the dewatering of the Tailings Impoundment and the collection and treatment of the discharge from the horizontal drain, or other drainage methods (e.g., vertical wells or drains), in a constructed wetland (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);
- Subaqueous disposal of Waste Rock Pile-3, Ore Pad, and Mine Operations Area source material, and Residential Use Area soil exceeding cleanup levels in a confined aquatic disposal (CAD) cell in the submerged former mine pit in Goose Pond;
- Excavation and off-site disposal of material contaminated with polychlorinated biphenyls (PCBs) exceeding site-specific PCB cleanup levels and petroleum-contaminated soil commingled with CERCLA waste;
- Dredging and subaqueous disposal of sediments exceeding the sediment cleanup levels from southern Goose Pond and the adjacent salt marsh into the CAD cell in the former mine pit;
- Mitigation, restoration, and compensation for wetland impacts, including the dredging and subaqueous disposal of Dyer Cove and Goose Cove sediments that contain mine waste in the CAD cell in the submerged former mine pit, along with other measures that may be identified in remedial design;
- Implementation of institutional controls to prevent disturbance to the components of the remedy and long-term monitoring of compliance with the restrictions;
- Installation of monitoring wells;
- Performance of long-term operation and maintenance, and monitoring; and
- Performance of five-year reviews to continue to evaluate potential human-health and ecological risks due to exposure to contaminated waste material being permanently managed on-site.
The OU2 Early Action would consist of land 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.
In 2010, EPA separated the OU1 Record of Decision activities into two components. The cleanup of the PCB contamination and the cleanup of the residential properties will remain OU1. The remaining components of the OU1 ROD, which includes the sediment excavation, waste rock excavation, disposal in the CAD cell, and cover system for the tailings impoundment will all become OU3. OU2 remains the component that will address groundwater contamination. EPA completed the cleanup of the residential properties with lead and arsenic contamination in 2011. EPA also completed the majority of the PCB excavation and disposal work in 2012. EPA completed the OU1 cleanup for the residential properties and PCB contamination in 2013.
EPA completed an Explanation of Significant Differences (ESD) for the Callahan Mine Superfund Site in September 2013. The This ESD documents the following changes to the OU1 ROD:
· Separation of the OU1 ROD components into two operable units, with the re-defined OU1 consisting of the: arsenic, lead, and thallium cleanup of the Residential Use Area; waste rock removal from the Ore Pad and portions of the former Mine Operations Area; and cleanup of the PCB contamination within the former Callahan Mine property. OU3 consists of the remaining components of the OU1 ROD;
· Expansion of the OU1 Residential Use Area cleanup to include one additional property which was found to contain soil contaminated with arsenic, lead, and thallium above the site-specific cleanup levels;
· Excavation and off-site disposal of a greater quantity of soil contaminated with PCBs than anticipated in the OU1 ROD, and on-site consolidation of a portion of the PCB contaminated soil (soil with PCBs greater than 1 ppm but less than 10 ppm) into the Tailings Impoundment for placement under the Tailings Impoundment cover system;
· Consolidation of the Residential Use Area soil into the Tailings Impoundment for placement under the Tailings Impoundment cover system; and
· Excavation of the waste rock at the Mine Operations Area and Ore Pad, and consolidation of such excavated material into the Tailings Impoundment for placement under the Tailings Impoundment cover system.
Response Action Status
|Operable Unit 1 and Operable Unit 3 Remedial Investigation and Feasibility Study ||Completed in 2009 along with Record of Decision for Operable Unit 1 and Operable Unit 3. |
|Operable Unit 1 Remedial Design ||Completed in 2010. |
|Operable Unit 1 Remedial Action ||Initiated in 2010 and was completed in 2013. The contaminated mine waste have been removed from the residential use area and this component of the OU1 cleanup is complete. The cleanup of the PCB contamination on the former Callahan Mine Corp property was completed in 2013. |
|Operable Unit 2 Remedial Investigation and Feasibility Study ||The Operable Unit 2 investigation program is expected to continue until the Operable unit 3 cleanup is completed. |
|Operable Unit 3 Remedial Design ||The design for the Operable Unit 3 Remedial Action is ongoing. The design for the tailing impoundment and horizontal drain component of OU3 was completed in 2015. The design for the waste area and sediment excavation and consolidation in the former mine pit is ongoing and is expected to continue through 2016. |
Remedial Investigatory efforts to determine the nature and extent of the contamination at the site began in November 2004. In June 2005, EPA, Maine DEP, and the Maine DOT entered into an enforcement agreement to allow the State of Maine to perform the investigation program. EPA and Maine DEP will be providing oversight. The investigation program will continue through 2008. A set of documents summarizing the work and assessing the potential risk at the Site will be completed in 2009. Additional site investigation activities were completed in 2007 and 2008. The Remedial Investigation Report, including the Human Health Risk Assessment and Baseline Ecological Risk Assessment, were completed in April 2009. The Feasibility Study was completed in July 2009. EPA released a Proposed Plan describing the cleanup approach for OU1 and the Early Action for OU2 in July 2009.
A public comment period began July 10, 2009 and ended on September 10, 2009. EPA held a public hearing on August 6, 2009. After consideration of the public input, EPA documented the OU1 cleanup decision in a Record of Decision signed on September 30, 2009.
In 2010, the Remedial Design for Operable Unit 1 was completed. The Remedial Action for Operable Unit was also initiated in 2010. In 2011, EPA completed the cleanup of the residential properties contaminated with arsenic and lead. In 2011, EPA also made substantial progress with the excavation and removal of the PCB contamination in the former Mine Operations Area. The Operable Unit 1 cleanup was completed in 2013. The design for the tailings impoundment and horizontal drain component of the OU3 cleanup was completed in 2015. The design for the waste area and sediment excavation and consolidation in the former mine pit is ongoing and is expected to continue through 2016.
Current Site Status
The implementation of the Operable Unit 1 cleanup action is complete. The Remedial Design for tailings impoundment and horizontal drain component of Operable Unit 3 was completed in 2015. The design for the remaining components of Operable Unit 3 and the Remedial Investigation for Operable Unit 2 will also continue in 2015 and into 2016.
Links to Other Site Information
Maps and Photos:
Newsletters & Press Releases:
Federal Register Notices:
Reports and Studies:
|Press Releases about this project   |
|Callahan Mining Corporation, A Proposed Superfund Site, June 11, 2002 (605 KB)   |
|Community Update, April 2005   |
|Community Update, July 2005   |
|Community Update: Remedial Investigation Field Work to Continue, June 2006 (9.87 MB)   |
|Community Update: Final Phase of Remedial Investigation Field Work, August 2007 (498 KB)   |
|Community Update, April 2009 (1.98MB)   || |
|Public Information Meeting for Proposed Cleanup Plan, July 09, 2009 (9.37 MB)   |
|Community Update, April 2010 (999 KB)   |
|Public Meeting Update, July 18, 2012 (2.15 MB)   |
|Final Hazard Ranking System Package, July 16, 2001 (2,344KB)   |
|Conceptual Model and RI/FS SOW, April 2003 (1,518KB)   |
|Final Public Health Assessment, April 17, 2003 (1,832KB)   |
|Draft Remedial Investigation (RI) Data Report, June 2005 (102 MB)   |
|Final Remedial Investigation Report, Executive Summary, April 1, 2009 (5.70 MB)    |
|Final Feasibility Study (FS) Report: Executive Summary, July 01, 2009 (10.01 MB)   |
|Final Feasibility Study (FS) Report, July 01, 2009 (Opening file is 23.5 MB with links to additional PDFs)   |
|Proposed Plan, July 01, 2009 (4.02 MB)   |
|Final Basis of Design Report - OU 1, September 23, 2010 (5.52 MB)   |
|Remedial Action (RA) Completion Report, September 26, 2013 (13.6 MB)   |
OSRR Records and Information Center, 1st Floor, 5 Post Office Square, Suite 100 (HSC), Boston, MA 02109-3912 (617) 918-1440
|EPA Remedial Project Manager: ||Ed Hathaway |
|Address: ||US Environmental Protection Agency|
5 Post Office Sq., Suite 100
Mail Code: OSRR07-1
Boston, MA 02109 - 3912
|Phone #: ||617-918-1372 |
|E-Mail Address: ||firstname.lastname@example.org |
|EPA Community Involvement Coordinator: ||Pamela Harting-Barrat |
|Address: ||US Environmental Protection Agency|
5 Post Office Sq., Suite 100
Mail Code: ORA20-1
Boston, MA 02109-3912
|Phone #: ||617-918-1318 |
|E-Mail Address: ||email@example.com |
|State Agency Contact: ||Naji Akladis |
|Address: ||Maine Department of Environmental Protection|
Station 17, State House
Augusta, ME 04333
|Phone #: ||207-287-7709 |
|E-Mail Address: ||firstname.lastname@example.org |