Region 8
Serving Colorado, Montana, North Dakota, South Dakota, Utah, Wyoming and 27 Tribal Nations
Superfund Program
National Information
Regional Information
Site Information
National Priorities List (NPL) History
Proposed Date
4/30/2003
Final Date
9/29/2003
Captain Jack
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Site Type: Active NPL City: Ward County: Boulder Street Address: T1N R73 W, SE 1/4 Sec. 12 Zip Code: 80481 EPA ID#: COD 981551427 Site ID#: 0800892 Site Aliases: Captain Jack Mill Congressional District(s): 02 |
Site Status & Updates
In June 2008, EPA and the Colorado Dept. of Public Health and Environment completed the Site's Final Remedial Investigation and Risk Assessment report and Feasibility Study report (RI/FS). The FS report contains a detailed analysis of remediation alternatives for various Site components. The Proposed Plan (PDF) presented EPA and CDPHE's preferred alternative for the remediation of the Site. A public meeting was held July, 2008, giving the community a chance to comment on the preferred remedy.
Overview of Selected Remedy
The selected remedy for cleaning up the Captain Jack Mill Superfund Site has two components, as it controls both surface and subsurface contamination sources.
To control subsurface contamination, the remedy (Alternative 3B in the Remedial Investigation / Feasibility Study) consists of an installed bulkhead, mine pool mitigation, and phased successive biochemical reactor treatment. The concrete bulkhead will plug the draining mine adit, impounding the mine water. The mine pool environment will have reduced oxygen levels, which, coupled with an injected caustic chemical, will increase the pH of the water to a neutral condition (Phase I). If necessary, after approximately two years of neutralization, the Colorado Department of Public Health and Environment may install a series of biochemical reactors outside of the mine (Phase II). The reactors use microorganisms to transform hazardous contaminants into non-hazardous substances. Following bioreactor treatment, the water would flow through wetlands for additional "polishing" treatment before entering Lefthand Creek. Because of uncertainties over the mine workings, there will be extensive groundwater monitoring once the bulkhead is installed.
Under the selected surface remedy (Alternative 2C), all waste will be excavated and placed in several onSite consolidation cells. The selected remedy calls for excavation of all Site material containing contaminants of concern in concentrations above the remedial action levels.
To contain the waste, each consolidation cell will have a cap. The caps will likely consist of a liner impervious to water, coarse material to prevent rainwater from seeping down and contacting the waste, and topsoil to support vegetation. Before the liner is placed on the waste, alkaline material would be mixed into the top six inches of the waste material to minimize acidic leaching. Officials will fully evaluate potential locations for the consolidation cells, as well as locations from which to borrow dirt for the cap, during the design phase.
Copies of the reports are available in both hard-copy and on electronic discs at the Site's Information Repositories in Ward, CO, and the public library in Boulder, CO.
Comments on the Proposed Plan were reviewed by the agencies and considered for the final remedy selection that was addressed in the Record of Decision, issued September 2008.
One of the main components of the Site is the Big Five Mine, located about 500 feet upstream from the mill. It consists of an adit (or tunnel), a large waste-rock pile and a setting pond. The tunnel is the main drainage conduit for acidic water leaving the mine.
Investigators recently discovered a roof-rock collapse and tunnel blockage 850 feet into the Big Five tunnel. Mine water has pooled behind the blockage. It is not known when the collapse occurred or how much pressure has built up behind it.
EPA has initiated an emergency response action. An emergency response is taken in response to a release or threat of release of a hazardous substance that could present an immediate or near-term threat to human health or the environment.
EPA has hired geo-technical experts to rehabilitate the tunnel so crews can safely get into the collapse area and attempt to drain off the pool mine water, thereby minimizing the potential for a sudden release to downstr
Mine water from behind the blockage will be drawn down and chemically neutralized in a controlled manner. While there is potential for discolored water in Lefthand Creek, no adverse effects are expected.
Regulatory agencies and local authorities are cooperating in the effort and will alert water customers immediately if any health concerns arise from the tunnel.
The web site for the Colorado Department of Public Health and Environment (CDPHE) has more information.
Visit the CDPHE Captain Jack Web Site
Site Description
The Captain Jack Mill Site is located at the headwaters of upper Left Hand Creek about 1.5 miles south of Ward in Boulder County, Colorado. The Site is in a narrow valley known as California Gulch. Mining for gold and silver in the region began in 1860 and ended in 1992.
The Site is comprised of the Big 5 Mine (the upper mine), Captain Jack, Ltd. mill, the Black Jack Mine (the lower portal), and other mines and waste features in the immediate surrounding area. The Big 5 Mine, located about 500 feet upstream from the mill, consists of an adit (tunnel), a large tailings pile and a settling pond. The mill works area includes several lagoons previously used for settlings tailings from the mill. The lower portal includes the Black Jack adit and the contents of a shed.
Other mine wastes include waste material in Left Hand Creek and waste rock from the mine tunnels. In the 1890s there was a mining community known as Camp Frances.
Site Risk
Adit drainage was found to be highly acidic in July 1986. In September 1986 the Mine Safety Health Administration found improper storage of chemicals. EPA removed several drums of chemicals and concentrated mine wastes in March 1987.
The Colorado Mined Land Reclamation Board received reports of dumping of mine and mill wastes into Left Hand Creek in October 1992. At the same time a milky white substance in Left Hand Creek was reported. Tailings like material was observed entering Left Hand Creek from the unlined tailings ponds turning the creek a milky gray color for about 6 miles downstream.
Sampling found high levels of zinc, cadmium, copper and lead. The Left Hand Water District shut off their drinking water intake 15 miles downstream on Left Hand Creek. The Colorado Department of Public Health and Environment issued a Notice of Violation and a Cease and Desist Order. The Colorado Department of Minerals and Geology obtained a restraining order to prevent further mill operations.
CDMG determined in 1993 that there was a threat to the environment from the tailings through blowing dust, surface flooding, overflow of the tailings pond and subsurface groundwater percolation. They also determined that there were improperly stored drums and explosives. A 1997 EPA inspection found elevated levels of heavy metals in the soils from the Big 5 Mine tailings pile and pond and in the unlined lagoon at the Captain Jack mill. EPA also confirmed the findings of earlier elevated levels of metals in the Adit drainage.
Water and sediment samples from Left Hand Creek showed elevated concentrations of metals, including zinc, cadmium, copper and lead.
| Media Affected | Contaminants | Source of Contamination |
| Solid waste, soils, surface water | Zinc, cadmium, copper and lead | Wastes from mining and smelting operations |
Cleanup Progress
With the completion of the remedial investigation and feasibility study for the Site in the spring of 2008, CDPHE and EPA presented a proposed plan for alternatives for the design and construction of the Site remedy for public review and comment. Following a public comment period, a remedy was selected and a Record of Decision (ROD) produced. Following the ROD, design and construction of the remedy will begin.
Planned Activity: The following are the tentative timelines for activities:
- September 2008: Issuance of Record of Decision, which selects the final remedy
- 2009 - 2010: Remedial Design
- 2010 - 2012: Construction
- 2013 - 2014: Monitoring and evaluation of Subsurface remedy Phase I
- 2015 - 2017: Subsurface remedy Phase II (if necessary)
Community Involvement
CDPHE (the lead agency for the cleanup response), EPA and the Lefthand Watershed Oversight Group (LWOG) host meetings with community members to update them on Site activities and proposals. The proposed plan for the Site remedy will require a public hearing and public comment period.
Local citizen volunteers have formed the Lefthand Creek TAG Coalition (LCTC) to monitor the cleanup of the Captain Jack Mill Site. Those involved in the organization are residents who live downstream from the Site, drink Lefthand Water District water, or like to recreate around Lefthand Creek.
Aided by a Technical Assistance Grant (TAG) of $50,000 from the Environmental Protection Agency, LCTC hired an independent technical advisor to help interpret and comment on Site-related information.
Site Documents
Note: the following documents are Adobe PDF files (about PDF files)
Record of Decision, September 2008 (PDF, 247 pp, 8 MB
Proposed Plan, June 2008 (PDF, 18 pp, 495 kB)
The following VERY LARGE PDF files are on the Captain Jack ftp Site folder:
Feasibility Study PDF, 202 pp, 50 MB
Final Remedial Investigation and Risk Assessment PDF, 531 pp, 94 MB
Contacts
Linda Kiefer
Environmental Scientist
U.S. EPA
1595 Wynkoop Street
Denver, CO 80202 - 1129
303-312-6689
kiefer.linda@epa.gov
Karen Edson
EPA Community Involvement Coordinator
U.S. EPA
1595 Wynkoop Street
Denver, CO 80202 - 1129
303-312-6136
edson.karen@epa.gov
Mary Boardman
CDPHE State Project Officer
HMWMD - RD.B2
4300 Cherry Creek Drive South
Denver, CO 80246-1530
303-692-3413
mary.boardman@state.co.us
Mark Williams
Water Quality Program Coordinator
Boulder County Public Health
3450 Broadway
Boulder, CO 80423
303-441-1143
mwilliams@co.boulder.co.us
Proposed Rule Supporting Documentation
Documents are available at:
|
Boulder Public Library
11th & Arapahoe Boulder, CO 80302 (303) 441-3100 |
Boulder County Health Dept. Environmental Health Div. 3450 Broadway Boulder, CO 80304 (303) 441-1190 |
| EPA Superfund Records Center 1595 Wynkoop Street Denver, CO 80202-1129 (303) 312-6473 |
CDPHE Records Center 4300 Cherry Creek Drive South Denver, CO 80246-1530 (303) 692-3331 |