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National Information |
Site Information |
National Priorities List (NPL) HistoryProposed Date Final Date |
Superfund Program
Summitville Mine
|
Site Type: Active NPL City: Del Norte County: Rio Grande Zip Code: 81132 EPA ID#: COD983778432 Site ID#: 0801194 Site Aliases: Summitville Consolidated Mine Congressional District: 3rd |
State of Colorado Summitville Mine Web Site
Site Description
The Summitville Mine Site (the "Site") is located 25 miles south of Del Norte, Colorado at an elevation of 11,500 feet above sea level in the San Juan Mountains of southwestern Colorado. The mine Site is situated south of Wightman Fork, a tributary of the Alamosa River, about two miles east of the Continental Divide. Mountain peaks surrounding the mine Site range between 12,300 and 12,700 feet elevation. The historic town of Summitville is just to the north of the mine Site on the other side of Wightman Fork. The area is traditionally subject to severe winters with heavy snowfall accumulating on steep slopes. Snow may often remain on the ground until late Spring or early Summer providing water in quantities sufficient to keep streams, including Wightman Fork, flowing year-round, and acting as a continual source of water entering the soil.
History
Gold and silver mining began at Summitville around 1870. Large-scale, open-pit mining began at the Site in 1984. The mine operator, Summitville Consolidated Mining Corp., Inc. (SCMCI), used cyanide heap leaching to extract precious metals from the ore. In this process, ore excavated from the mountain was crushed and placed onto the clay and synthetic-lined Heap Leach Pad (HLP). A sodium cyanide solution was then applied to leach out gold and silver.
Almost immediately after its construction in 1986, a leak was detected in the HLP. SCMCI abandoned the Site and announced it was filing for bankruptcy in December 1992. The EPA immediately assumed responsibility of the Site as an emergency response. On May 31, 1994, Summitville was placed on the National Priorities List (the "NPL") of Superfund Sites.
Site Risk
The chemicals of concern are heavy metals (copper, cadmium, manganese, zinc, lead, nickel, aluminum, iron) on Site and in the acid mine drainage.
Mining operations deforested and greatly disturbed most of the land area at the Site. Because of the highly mineralized character of the Site, almost all exposed earthen materials are capable of acid generation. This acid mobilizes the variety of metals that contaminate the Alamosa River system below the Site. Surface water quality downstream of the mine has been degraded by low pH (acidic water), and elevated dissolved solids and heavy metals (especially copper.)
Human exposure to these contaminants is limited, since no one lives on-Site or within two miles, and Site groundwater is not used for drinking. Drinking water wells for San Luis Valley residents living downstream of the Site have been sampled on numerous occasions and have never shown elevated metals concentrations associated with the Site. In 1997, the Agency for Toxic Substances and Disease Registry (ATSDR) released a Public Health Assessment that classified the Summitville Site as no apparent public health hazard. However, ecological impacts from Site contaminants have been considerable as the Alamosa River system below the Site cannot currently support aquatic life. Study is on-gong regarding potential adverse effects to agriculture and livestock from regular use of Alamosa River water. Preliminary results have indicated some uptake of metals in livestock and some agricultural soil degradation from irrigation; however, in both cases the effects have not been of a level that affects the viability of local farm products or impacts the food chain.
Cleanup Progress
Since 1992, EPA and the Colorado Department of Public Health and Environment (the "CDPHE") have initiated several interim projects designed to slow the amount of acid mine drainage coming from the Site. These interim projects have included 1) detoxifying, capping and revegetating the HLP; 2) removing waste rock piles and filling the mine pits; 3) plugging the adits or underground mine entrances; and 4) expanding the water runoff holding ponds and operating a water treatment plant on-site. The CDPHE led the largest interim measure to be implemented: Site-Wide Reclamation and Revegetation. In addition, the CDPHE led the Remedial Investigation and Feasibility Study (the "RI/FS") for the Site, beginning in 1998. The RI/FS evaluated the effectiveness of the interim measures that have been completed, or that remain ongoing at the Site, and determined what final construction projects or long-term measures must be added in order to wrap up the Site cleanup in the future. The RI/FS culminated with a site-wide Record of Decision (the "ROD") issued in the fall of 2001.
Completed and Ongoing Site Construction Work
Over the course of the summer field season, the Site cleanup requires approximately
2,300 kilowatt hours of electrical power, costing the state of Colorado and
EPA approximately $80,000. Energy costs for Site operations likely will increase
in the future. To defray the costs, to add a measure of self-sufficiency and
to support renewable energy, EPA and the State have embarked on design and installation
of a penstock (narrow pipe) and turbine. The penstock and turbine comprise a
microhydro power plant, which will capture the water power and convert it to
energy as it flows downhill from the Site. Penstock construction began this
year; turbine installation is planned for 2009. The elevation drops approximately
64 feet between the Water Treatment Plant discharge point and the Wightman Fork
downstream of the Summitville Dam Impoundment (the "SDI"). Once workers
construct the microhydro power plant, the water flowing from the water treatment
plant through the penstock into Wightman Fork will be 'harvested' for energy
to back-feed the power grid, offsetting power use at the Site. The penstock
pipeline is buried beneath Pinos Creek Road, north of the newly installed Wightman
Fork arched culverts. It will deliver Wightman Fork and SDI discharge water
to the turbine at approximately 10 cubic feet per second. The microhydro power
plant will generate approximately 56 kilowatts of energy for a cost savings
of $9,000 to $15,000 per year (i.e., the seven months of operation).
Both the EPA and the state of Colorado have pushed for the microhydro power
plant installation and are looking for other opportunities to employ energy-efficient
processes and operations at the Summitville Mine Superfund Site.
Wightman Fork Diversion
The Wightman Fork Diversion (the "WFD") is a vestige of the early days of Summitville mining. Damming the low axis of the valley to store liquid wastes generated by mine operations disrupted the natural flow of the creek. The WFD then diverted Wightman Fork so it could bypass the contaminated water storage area, preventing co-mingling of clean water with the stored contaminated water. During the hydrologic basin analysis conducted for the Summitville Mine Superfund Site, the WFD was determined to be of inadequate size to pass the minimum 100-year recipitation event. In 2007, the state hired a consultant to design an upgrade to the WFD so it could safely hold flows from a 100-year precipitation event, and to route a 500-year precipitation event through the Summitville Dam Impoundment (SDI) spillway channel. Because of the diversion's proximity to the SDI dam, the State Engineer's Office reviewed and approved prospective designs.Following the Engineer's Office review, a contractor, American Civil Constructors, began construction on the approved design. Work began in 2008 and will continue through 2009. It involves upgrading the deteriorated and undersized culverts and channel with a combination of channel widening, hard-rock erosion control, sheet pile retaining walls, and emergency overflows from the diversion into the SDI. Most noticeably, workers installed two arched culverts around the SDI, each measuring ten feet tall, 10 feet wide and 275 feet long.
The WFD has long been a bottleneck for water flows during spring run-off and storm events. This work on the WFD improves a major element of Site surface water management.
New Aluminum Standards Set for the Alamosa River
The CDPHE's Hazardous Materials and Waste Management Division proposed changes
to the aluminum standards in Alamosa River segments 3A, 3B, 3C, 3D and 8. Because
of natural sources, the current acute and chronic numeric standards for aluminum
in these
segments cannot be met under any circumstance. Natural contributing sources
include mineralized terrain in the Stunner, Summitville and Jasper Altered Areas.
Human-induced sources include legacy mines in the Stunner, Summitville and Jasper
Altered Areas, as well as the Summitville Superfund Site.
After accounting for the reversible human-induced sources, CDPHE calculated
aluminum values that could be adopted as new, reasonable standards. The Water
Quality Control Commission accepted the proposed standards in June 2007. Ambient
(or existing conditions) standards apply to Alamosa River segments upstream
of Wightman Fork. Technology-based standards-which take into account the achievable
aluminum removal using a water treatment plant-apply to Alamosa River segments
downstream of Wightman Fork.
History 1992 to Present
| 1992-1994 | EPA and CDPHE Emergency Response at abandoned Summitville Mine |
| 1994 | Interim Record of Decision: 1: Water Treatment Plant, 2: Cropsy Waste Pile, Beaver Mud Dump, Summitville Dam Impoundment (the "SDI") and Mine Pits, 3. HLP, and 4. Reclamation |
| 1994-1995 | HLP Detoxification |
| 1994 | Reynolds Adit Bulkhead |
| 1996 | Cropsy Waste Pile, Beaver Mud Dump, SDI, and Mine Pit Closure |
| 1996-2000 | Modification to the existing Water Treatment Plant |
| 1994-1998 | Cropsy Valley restoration and revegetation |
| 1998 | HLP Cap complete |
| 1998 | Completion of HLP, North Waste Dump |
| 1998-2001 | Site-wide RI/FS |
| 2001 | Site-wide ROD |
| 2002 | Complete Site-wide Reclamation |
| 2004 | Complete Water Treatment Plant Design |
| 2004-2005 | Complete Contaminant Source Collection Structures |
| 2005 | CDPHE assumes lead role for Water Restoration Plan (the "WRP") and Site O&M |
| 2006 | Rule Change before the Water Quality Control Commission for the Alamosa River |
| 2008-2009 | Wightman Fork and SDI Improvement, Installation of Microhydro Power |
| 2010 est. | Begin Construction of new Water Treatment Plant |
Related Web Sites
Agency for Toxic Substances and Disease Registry (ATSDR) Public Health Assessment
Community Involvement
CDPHE (the lead agency for the cleanup response), hosts yearly meetings in the spring and fall to update the public about work accomplished for that year, and about upcoming projects.
There is an active Technical Assistance Grant (the "TAG") community
group that has been working with the Site managers for several years. The Riverkeepers
is another community group actively involved with the Site.
Site Documents
Note: the documents below are Adobe PDF files (About PDF files)December 2005 Fact Sheet PDF (8 pp, 610K)
Five Year Review Report - September
27, 2005 PDF ( 256 pp, 25MB)
Note: this links to a public ftp Site containing the very large PDF.
The best way to download the PDF file is to right-click on it, select Save Target
As, and select a folder in which to save the file.
Five Year Review Annual Update, March 2009 PDF (4 pp, 48K)
Summitville Community Involvement Plan, September 2005 PDF (45 pp, 475K)
Record of Decision, September 28, 2001 PDF (138 pp, 1.4MB, about PDF)
Five Year Review Report - August 3, 2000 PDF
(2MB)
Contacts
|
EPA |
Colorado |
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View Documents at: EPA Superfund Records Center Del Norte Public Library Conejos County ASCS Office |
Neighborhood group The Summitville TAG |
