Eagle Mine Superfund Site MonitoringThe Eagle Mine site is located in Eagle County between the towns of Minturn and Red Cliff. The site is comprised of an inactive mining and milling facility, associated waste rock and former roaster pile areas, a consolidated tailings pile, the abandoned Town of Gilman, Belden mill area, Rex Flats, Rock Creek Canyon and the Maloit Park wetlands. The Eagle River, Cross Creek and several other Eagle River tributaries run through the site. It was designated as one of Colorado’s “Superfund” hazardous waste sites by the U.S. Environmental Protection Agency (EPA) in 1986.

The Issue

Eagle Mine Superfund Site MonitoringERWC monitors the health of the river below the site, but does not conduct the clean up. ERWC – Eagle Mine Limited – Eagle Mine Limited is a separate non-profit organization created to inform the community about clean up efforts. The grant to provide public information regarding the Eagle Mine Superfund Site was initially sought by the Eagle River Watershed Council. Due to EPA rules regarding Technical Assistance Grants, it became necessary to form a separate non-profit from the Eagle River Watershed Council. EML is that separate nonprofit corporation.

An overview of ERWC’s monitoring efforts are described below. To learn more about the Superfund Site cleanup, please visit our Eagle Mine Superfund Site webpage.

Latest Updates

In 2014, ERWC coordinated two important meetings regarding the Eagle Mine cleanup. The first was a Watershed Wednesday with CBS, Newfields and Environ giving a community update on the cleanup effort. The meeting was open to the public and was a great way for people to understand the cleanup from all sides.

A few weeks after that presentation, Eagle Mine Limited and ERWC coordinated a meeting of Colorado Department of Public Health & Environment (CDPHE), Environmental Protection Agency (EPA) and local stakeholders to receive an update on the Focused Feasibility Study and Proposed Plan. The powerpoint presentations and meeting minutes are included below:


Water Quality in the Eagle River below the Eagle Mine is impaired by high levels of zinc, copper, and cadmium, which impair aquatic life. Currently the river from Red Cliff to the confluence with Gore Creek and through the Eagle Mine Site supports a brown trout population which is somewhat impaired by concentrations of these heavy metals. Water quality in this reach does not meet the table value standards for Cold Water Aquatic life (Class 1) set by the Colorado Water Quality Control Commission with regard to these heavy metals. As a result, sculpin, a native fish, do not inhabit the Eagle River from Belden downstream to the confluence with Gore Creek. Very few rainbow trout are found in this reach either.

Eagle Mine Superfund Site MonitoringOn June 9, 2008, the Colorado Water Quality Control Commission held a hearing to reconsider water quality standards in the Colorado River basin, including the Eagle River. The water quality standards adopted by the Commission will be a pertinent issue in the 5 year review of Superfund Site activities. In the 5 year Superfund site review, CBS, as a responsible party, and the Hazardous Materials and Waste Management Division will attempt to arrive at an agreement that defines future cleanup that will be required. In these negotiations, the Hazardous Materials and Waste Management Division seeks further cleanup activities that are expected to result in a reduction of zinc loading to the river from the current 120 pounds per day to between 37 and 41 pounds per day.

While this level of reduction will certainly cause an improved aquatic environment and healthier brown trout population, it is not expected that water quality will be improved to the extent necessary for the Eagle River to support a healthy rainbow trout population in the reach between the Eagle Mine and Gore Creek. To better understand how zinc determines what fish will be present in the river check out this slide presentation.

Water Quality Monitoring

ERWC monitors the water quality in the Eagle River at three sites below the mine on a monthly basis. You can learn more about that on our River Watch of Colorado page.

Biological Health Monitoring

Since 1989 the Hazardous Material and Waste Management Division of the State Health Department asked Colorado Parks and Wildlife (CPW) to sample the Eagle River for fish. Sampling means collecting as many fish as possible which inhabit a defined river. Each fish collected is measured and examined. The collection process is accomplished by introducing a mild electric current into the water to attract and temporarily stun the fish so that they may be safely and quickly netted.

A number of sites were monitored — above the Eagle Mine, at the mine, and several sites below the mine. The river has been sampled each April from 1990 through the current year.

Fish sampling, in other rivers, is not normally done in the spring; however spring sampling demonstrates the impact of the high metal ion concentrations on the fish present in the winter months. The sole reason behind the sampling program was to assess the efficacy of the Eagle Mine CERCLA (Comprehensive Environmental Response, Compensation, and Liability Act, more commonly known as Superfund) cleanup project.

A number of sites are sampled: a control site at Arrowhead, at just north and south of Minturn, just below Two Elk Creek, at Two Elk Creek, just below the effluent of the mine water treatment plant, at the mine, and at the confluence of the Eagle and the Homestake near Red Cliff.