Skip common site navigation and headers
United States Environmental Protection Agency
Region 8 - Superfund
  Serving Colorado, Montana, North Dakota, South Dakota, Utah, Wyoming and 27 Tribal Nations
Begin Hierarchical Links EPA Home > Region 8 > Superfund > Sites > Colorado Cleanup Sites > Active NPL Sites > Summitville Mine End Hierarchical Links


Superfund Basics

Risk Assessment



Congressional Reports

Public Liaison


Summitville Mine

Colorado, Rio Grande County, Congressional District #3,
EPA ID# COD 983778432

National Priorities List
Remedial Action Underway
April 2003


The Summitville Mine site covers about 1,400 acres of Rio Grande County. It lies some twenty miles southwest of Del Norte, high in the San Juan Mountains of southwestern Colorado. It is an abandoned gold mine that was leaking cyanide, acid and metal-laden mine water into the headwaters of the Alamosa River. The pollutants killed aquatic life and threatened the irrigated farmland downstream. The State of Colorado, citizens of the San Luis Valley and the U.S. EPA are working together to clean up the site.


Mining began at Summitville in the 1870s. In the 1980s, Summitville Consolidated Mining Company, Inc. (SCMCI) started large-scale surface gold mining, using the heap-leach process. Pyritic, gold-bearing ore was mined, crushed and stacked or heaped on a multi-layered, lined pad. A solution of sodium cyanide was used to leach gold from the ore. It was sprinkled on the heaped ore and allowed to percolate down through it. Then the sodium-cyanide solution was pumped to a facility that removed the gold. The mining greatly increased the acidity and dissolved metals in the surrounding streams, damaging aquatic life. Those dissolved metals include aluminum, copper, iron, manganese and zinc.


  • Backfilling mine waste into the existing open pits, which reduced water leaching into the ground;
  • Rinsing the heap-leach pad to reduce the cyanide;
  • Regrading and capping the heap-leach pad to reduce the seepage of snow melt and summer rain;
  • Plugging two mine adits (passages into the underground mine) to significantly reduce water flow from the mine workings;
  • Constructing a 90-million-gallon wastewater holding pond for treatment to remove metals and acidity;
  • Replanting 585 acres of mining-disturbed land.

Additional long term activities are ongoing: Retrofitting a water-treatment plant that is capable of treating 1000 gallons of water per minute. Monitoring surface water and seepage to evaluate the effectiveness of the water-control strategy.

Mine reclamation activities were completed in October 2001. They included constructing more
storm-water controls, and reshaping and replanting the mining-disturbed lands. The soils were
prepared with a mixture of crushed limestone and organic compost to help the grass seed grow in
the acidic soils. Some 585 acres have been restored. They now support plant and wildlife habitat. Studies have been completed of soil amendments; reclamation practices; exposure effects on livestock, wildlife and irrigated cropland.

The site was added to the Superfund National Priorities List in May 1994. So far, about $155 million has been spent on the Summitville project. Water quality of the Alamosa River downstream of the site has improved considerably. Residents have reported the return of aquatic life to impacted areas of the river.

As a result of these reports, CDPHE conducted a caged-fish experiment to see if rainbow trout would survive in various locations in the Alamosa River and the Terrace Reservoir. During the 96-hour exposure study, all of the rainbow trout survived. At the end of the study, the fish were released. This experiment has been viewed as one indication of water-quality improvement in the river and does not imply that remedial work there is complete.


The final site Remedial Investigation and Feasibility Study (RI/FS), led by CDPHE, were completed in summer 2001. After considering public comment, EPA and CDPHE selected a final remedy for the site in September 2001. The goal of the remedy is to restore both water chemistry and aquatic life in the Alamosa River and Terrace reservoir.

The final remedy includes:

  • containment of contaminated water from the mine
  • construction of a new water-treatment plant
  • possible construction of a large containment reservoir
  • contaminated ground water and surface water interceptor drains
  • site maintenance

Design of the water-treatment plan will continue throughout 2003, with construction beginning in 2004. It is scheduled to be completed in 2005.

Thus far, the Agency has recovered a small percentage of the cost from settlements with responsible parties, including Robert Friedland. The money will be used for ongoing cleanup actions at the site, and for restoration, acquisition, or replacement of natural resources. The majority of cleanup costs are being paid by the EPA Superfund program and the State of Colorado.


A group of concerned community members, has a Technical Assistance Grant (TAG) from EPA. The purpose of a TAG is to hire an independent technical advisor to review cleanup issues and help inform the community.

April 2003

[Active NPL Sites][Summitville Proposed Plan][Alamosa River Test][Summitville Photo][Summitville Waste Pond][Summitville Pad Cap][Summitville Contacts][Summitville Map]

Record of Decision (ROD) List

The table below lists all available documents for this site.  All full-text RODs are in PDF format.  To download a full-text ROD, right click on the link below and select Save Link As.  To view a full-text ROD or abstract, click the appropriate link below.  Please note that download time may be extended given the size of the full-text document.  File size is noted in kilobytes (K) or megabytes (M) next to each download link.   If file size exceeds 15 M, please request a customized RODS report.
About Adobe Portable Document Format

Fiscal Year
ROD Type ROD Date Operable Unit(s)    
1995 ROD 12/15/94  00  Abstract  Full-text [251K]
1995 ROD 12/15/94  01  Abstract  Full-text [189K]
1995 ROD 12/15/94  02  Abstract  Full-text [183K]
1995 ROD 12/15/94  04  Abstract  Full-text [194K]
Other Colorado RODs
Begin Site Footer

EPA Home | Region 8 Home | Privacy and Security Notice | Contact Us | Search EPA