Region 8

Summitville Mine

Summitville Mine site location map Site Type: Final NPL
City: Del Norte
County: Rio Grande
ZIP Code: 81132
EPA ID: COD983778432
SSID: 08Y3
Site Aliases: Summitville Consolidated Mine
Congressional District: 3

What's New?

Updated January 2015

Summitville Mine Superfund site first in nation to get power from a community solar garden

Antonito Community Solar Garden

The Summitville Mine water treatment plant sits high in the majestic mountains of southwestern Colorado, and EPA and the State of Colorado are seeking ways to reduce the electricity bill for treating the contaminated water that drains from the mine. The idea of installing solar panels at the mine never received much consideration as they would be covered by deep snow drifts much of the year. However, snow accumulation is no problem in the town of Antonito (approximately 40 miles to the south), so when EPA and the State heard that a community solar garden was being constructed in the town (on an old dump site), and that Summitville could receive energy from the project, the project team got excited. Colorado, the lead agency for the long-term operation and maintenance at the site, just signed a 10-kilowatt subscription (about 40 panels). All the electricity produced by those 40 panels will be credited to the Summitville electric bill as if the panels were located on the roof of the treatment plant. This subscription will generate enough electricity to power two and a half average homes, and will reduce global warming pollution by 15 metric tons per year. It will only cover a small portion of the treatment plant’s energy needs, but the State and EPA are hopeful that the opportunity to acquire a larger subscription will present itself soon.

The fourth five-year review of the Summitville Mine site will be conducted in 2015, with the five-year review report finalized no later than September 2015. Five-year reviews are conducted at sites where waste has been left in place. The purpose of the five-year review is to determine if the remedy is working and if it remains protective of human health and the environment. The third five-year review was completed in 2010 and the report is available in Site Documents.

The Summitville site achieved the site-wide construction completion milestone as documented in the Preliminary Close Out Report signed on September 30, 2013.

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Site Description

The Summitville Mine 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.

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. EPA immediately assumed responsibility of the site as an emergency response. On May 31, 1994 Summitville was placed on the National Priorities List (NPL) of Superfund sites.

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Site Risk

Media Affected Contaminants Source of Contamination
surface water, groundwater, soil copper, cadmium, manganese, zinc, lead, nickel, aluminum, iron mining

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 are then discharged and contaminate the Alamosa River system below the site. Surface water quality downstream of the mine has been degraded by low pH (acidic) water and by elevated levels of 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 having 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-going 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.

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Cleanup Progress

The work at the site since 1992 has included both emergency response actions and remedial response actions designed to slow the amount of acid mine drainage coming from the site. Work has been conducted by EPA and the Colorado Department of Public Health and Environment (CDPHE) working cooperatively. For manageability, the site was divided into these operable units (OUs) and emergency response actions:

Plugging of the Reynolds and Chandler Adits (Emergency Response)

  • OU0: Interim Water Treatment
  • OU1: Heap Leach Pad Detoxification/Closure
  • OU2: Mine Waste Excavation and Mine Pit Closure
  • OU3: South Mountain Groundwater (incorporated into OU5)
  • OU4: Site-Wide Reclamation
  • OU5: Final Site-Wide Remedy (including the Wightman Fork Diversion reconstruction).

Interim Records of Decision (RODs) were issued for OU0, OU1, OU2 and OU4 in December 1994. An interim ROD was not issued for OU3, South Mountain Groundwater, but OU3 was included in the subsequent scope of work for OU5. The ROD for OU5, Final Site-Wide Remedy, was issued in September 2001. An Explanation of Significant Differences (ESD) to the OU5 ROD was issued in August 2003, which addressed a change in the location for the proposed water treatment plant (WTP). An additional ESD to the OU5 ROD is under development, which is anticipated to document the postponement of the construction of a new repository for WTP sludge disposal and the reconstruction of the Wightman Fork Diversion (WFD) rundown structure. This future ESD, to the extent deemed necessary, also will incorporate additional Institutional Controls (ICs) at the site.

CDPHE led the largest interim measure to be implemented: site-wide reclamation and revegetation. In addition, CDPHE led the remedial investigation and feasibility study (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, and determined what final construction projects or long-term measures were necessary for the site. The RI/FS culminated with a site-wide Record of Decision (ROD) issued in the fall of 2001, and ultimately, the construction of a new water treatment system.

Wightman Fork Diversion

Photo of the Wightman Fork Rundown Structure at the Summitville Mine Superfund Site
Wightman Fork Rundown Structure

The Wightman Fork Diversion (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 commingling of clean water with the stored contaminated water. During the hydrologic basin analysis conducted for the Summitville Mine site, the WFD was determined to be of inadequate size to pass the minimum 100-year precipitation event. In 2007, CDPHE 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, 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. 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 10 feet tall, 10 feet wide and 275 feet long.

The WFD has long been a bottleneck for water flows during spring runoff and storm events. This work on the WFD improves a major element of site surface water management. After the 2009 to 2012 spring runoff events, EPA and CDPHE noticed significant erosional damage to the Wightman Fork rundown structure and determined that the structure was inadequate to withstand high flood events. EPA’s Emergency Response team mobilized to the site in September 2012 and started to reconstruct a structure designed to convey 100-year rainfall event. Construction was completed in July 2013.

New Aluminum Standards Set for the Alamosa River

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 Mine 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.

The American Recovery and Reinvestment Act (ARRA)

In previous decades, the Summitville Mine discharged a large amount of copper and other metals contamination to Wightman Fork and the Alamosa River in the San Juan Mountains of Colorado. Now, thanks to the $17 million received from the American Resource and Recovery Act, we built a new water treatment plant to address the discharges. Funds from the act paid for 90 percent of the new water treatment system; the Colorado Department of Public Health and Environment (CDPHE) provided the remaining 10 percent. A wide range of techniques were used during the site cleanup from the consolidation and capping of mine waste, the containment and treatment of contaminated water, to the innovative use of green technology.

These actions will continue to improve the macro-invertebrate community, the trout population and the water quality in the Alamosa River.

The construction projects at Summitville provided more than 100 construction jobs in this area, and the cleanup significantly contributed to improving the water quality and restoring fish and aquatic life to the Alamosa River and Terrace Reservoir.

History 1992 to Present

1992-1994 EPA and CDPHE emergency response at abandoned Summitville Mine
1994-1995 HLP detoxification
1994 Reynolds adit bulkhead
1996 Cropsy Waste Pile, Beaver Mud Dump, SDI, and mine pit closures
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 (WRP) and site O&M
2006 Rule change before the Water Quality Control Commission for the Alamosa River
2008-2011 Wightman Fork and SDI improvement, installation of micro-hydro power
2011 Completed construction of new water treatment plant

Completed reconstruction of the Wightman Fork rundown structure; Summitville Mine site achieved the site-wide construction completion milestone

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Community Involvement

Community involvement plays an important role in the Superfund process. EPA uses a number of different tools and resources to promote effective, on-going, meaningful community involvement. The goals of the Superfund community involvement program are to:

  • Keep communities affected by sites informed throughout the cleanup process
  • Provide opportunities for communities to comment and offer their input about site cleanup plans
  • Facilitate the resolution of community issues tied to a site

The site is in a remote location at high elevation and no one lives on the site or within two miles of the site. Community outreach to the broader community will be conducted during the five-year review in 2015.

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EPA places a high priority on land reuse as part of its Superfund response program mission. The agency tries to select cleanup options that encourage and support future use of a site. EPA uses two fundamental methods to facilitate reuse of Superfund sites:

  • Exploring future uses before the cleanup remedy is implemented, an approach that gives the Agency the best chance of designing cleanup remedies to support the likely future use of a site.
  • Working with landowners and communities to remove barriers not considered necessary for the protection of human health or the environment at those sites where remedies are already in place.

One option for reuse is the siting of clean and renewable energy projects on contaminated (or formerly contaminated) lands. As part of this effort, EPA is evaluating the potential for energy projects on these properties and working with landowners and communities to identify ways to remove barriers to such projects.

Over the course of the summer field season, the site cleanup requires approximately 2,300 kilowatt hours of electrical power, costing CDPHE and EPA approximately $80,000. Energy costs for site operations likely will increase in the future. To add a measure of self-sufficiency and to support renewable energy, EPA and CDPHE have installed a hydro power plant at the site.

The inlet structure, penstock (a pipe that conveys water to the turbine) and foundation for the powerhouse were constructed in 2008. The powerhouse was built and a 35-kilowatt turbine was installed in the fall of 2010. The plant became operational in 2011 (see brochure below). The water entering the inlet structure flows through the penstock where it powers the turbine before re-entering. The hydro plant will provide a small percentage of the site’s energy needs and result in a reduction of carbon dioxide emissions during the roughly seven months it operates each year. Both EPA and CDPHE have pushed for the micro-hydro power plant installation and are looking for other opportunities to employ energy-efficient processes and operations at the Summitville Mine Superfund Site.

Read more about this energy-saving innovation: Hydroelectric plant powers contaminated water treatment at former gold mine(1 pg, 318 K, About PDF).

Colorado, the lead agency for the long-term operation and maintenance at the site, signed a 10-kilowatt subscription (about 40 panels) at a community solar garden in January 2015. The community solar garden is located in the town of Antonito, located about 40 miles to the south and at a much lower elevation with much milder winters. All the electricity produced by those 40 panels will be credited to the Summitville electric bill as if the panels were located on the roof of the treatment plant. This subscription will generate enough electricity to power two and a half average homes, and will reduce global warming pollution by 15 metric tons per year. It will only cover a small portion of the treatment plant’s energy needs, but the State and EPA are hopeful that the opportunity to acquire a larger subscription will present itself soon.

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Land Use Controls and Other Institutional Controls

Land use controls are the most common type of institutional control (IC). ICs are administrative or legal controls that help reduce the likelihood for human exposure to contamination. ICs can also help protect the integrity of the remedy. Examples of ICs are:

  • Zoning ordinances
  • Environmental covenants
  • Deed notices
  • Well-drilling restrictions
  • Building permits
  • Informational advisories

Institutional control options are currently being developed for the site in order to provide long-term protectiveness of the remedy. These ICs will be documented in a modification to the record of decision for the site.

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Five-Year Reviews

EPA or the lead agency conducts five-year reviews following the start of a Superfund cleanup when contamination is left on the site. These reviews are repeated every five years. We use these reviews to determine:

  • How the remedy is working
  • If the remedy remains protective of human health and the environment

CDPHE (the lead agency for the cleanup response) with EPA’s oversight conducted the third five-year review in 2010. The report is posted in Site Documents below. The second five-year review for the site will be completed no later than September 2015.

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Site Documents

You will need Adobe Reader to view some of the files on this page. See EPA’s About PDF page to learn more

Preliminary Close Out Report, September 2013

Remedial Action Completion Report (text, tables and figures only), September 28, 2012

Brochure: Micro-hydroelectric Power Generation at Summitville, August 23, 2011

Update to the Five-Year Review, January 2011

Third Five-Year Review Report (PDF), September 2010 (102 pp, 788 K)

Summitville Community Involvement Plan, September 2005

Explanation of Significant Differences for OU5, August 1, 2003

OU5 Record of Decision (PDF), September 28, 2001 (87 pp, 1.4 MB)

OU4 Record of Decision (PDF), December 15, 1994 (87 pp, 194 K)

OU2 Record of Decision (PDF), December 15, 1994 (73 pp, 181 K)

OU1 Record of Decision (PDF), December 15, 1994 (80 pp, 188 K)

OU0 Record of Decision (PDF), December 15, 1994 (110 pp, 252 K)

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Fran Costanzi
Remedial Project Manager
U.S. Environmental Protection Agency, Region 8
1595 Wynkoop Street (8EPR-SR)
Denver, CO 80202-1129
800-227-8917 ext. 312-6571 (toll free Region 8 only)

Site Document Repositories:

Del Norte Public Library
790 Grand Avenue
Del Norte, CO 81132

Colorado Department of Public Health and Environment
HMWMD Records Center
4300 Cherry Creek Drive South
Denver, Colorado 80246-1530
888-569-1831 ext. 3331 (toll free)
303-759-5355 FAX
By appointment only

EPA Superfund Records Center
1595 Wynkoop Street
Denver, CO 80202-1129
To request copies of administrative record documents call:
800-227-8917 ext. 312-7273 (toll free Region 8 only)


Mark Rudolph
State Project Manager
Colorado Department of Public Health and Environment
4300 Cherry Creek Drive South
Denver, CO 80246-1530
888-569-1831 ext. 3311 (toll-free)

Warren Smith
Community Relations Manager
Colorado Department of Public Health and Environment
4300 Cherry Creek Drive South
888-569-1831 ext. 3373 (toll free)

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Photo/Video Gallery

Click on a thumbnail below to view the full size image.

Remedial action work begins
Sept. 13, 2009
Drilling caissons, preparing the surface
Sept. 30, 2009
Drilling caissons, preparing surface for WTP foundation
Sept. 30, 2009
Protecting the WTP foundation
Nov. 3, 2009
Conceptual model of completed WTP

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Summitville Mine site at the Colorado Department of Public Health and Environment Exit

ATSDR Public Health Assessment, August 5, 1997

U.S. Fish and Wildlife Service: Alamosa River Watershed – Summitville

USGS: The Summitville Mine and its Downstream Effects

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