Gold King Mine and Bonita Peak Mining District

Site History:

On August 5, 2015, EPA’s Superfund Removal program conducted an investigation and assessment of the Gold King Mine near Silverton, Colorado. While excavating above the old adit, pressurized water began leaking above the mine tunnel, spilling about three million gallons of contaminated water stored behind the collapsed material into Cement Creek, a tributary of the Animas River.

Use this link to see footage of the release:

The Bonita Peak Mining District (Site) was proposed for addition to the National Priority List (NPL) on April 7, 2016. A 68-day public comment period, during which EPA accepted comments from the public on the NPL proposal, closed on June 13, 2016. EPA officially added the Site to the NPL on September 9, 2016. The Site consists of 48 historic mines or mining-related sources where ongoing releases of metal-laden water and sediments are occurring within the Mineral Creek, Cement Creek and Upper Animas River drainages. Near Silverton, Colorado, these drainages join to form the Animas River, which flows into New Mexico and is used for drinking water, recreation and agricultural purposes.


The primary location of the Site is north of Silverton in southern Colorado. New Mexico is a downstream community impacted by the mines in Colorado.

Potential Trustees:

State of New Mexico
State of Colorado
State of Utah
Navajo Nation
Southern Ute Tribe


The Natural Resource Damage Trustees have not yet been established for the Site. Once a Trustee Council is established, the objective will be to determine if natural resources have been injured as a result of the release of hazardous substances from the Site and to use recovered damages to restore, rehabilitate, replace, or acquire the equivalent of the injured resources.

Additional information related to the Site and the Gold King Mine Spill (part of the Site) can be found at the New Mexico Environment Department Website: and several EPA websites:,

Case Status:

The ONRT is actively working on this Site in close collaboration with the New Mexico Environment Department and has been invited to participate in a Biological Technical Assistance Group based in EPA Region 8.  EPA hosted several public meetings in Colorado and Navajo Nation.  New Mexico is requesting a similar meeting for its citizens.

EPA Letter to ONRT-11-14-16

In January 2021, the State and the Mining Defendants reached a settlement that includes a payment of $1 million by the Mining Defendants to the Office of the New Mexico Natural Resource Trustee (“ONRT”) to implement natural resource restoration projects.

The New Mexico Office of the Natural Resources Trustee (ONRT) is seeking stakeholder input and ideas for restoration projects to be funded through a proposed $1 million settlement with Sunnyside Corporation and its parent companies, Kinross Gold Corporation and Kinross Gold, U.S.A., Inc., collectively referred to as the “Mining Defendants”.

Invitation to propose ideas for natural resource restoration projects related to 2015 Gold King Mine release

GKM Restoration Project Solicitation Public Webinar FINAL 2021.07.28

Natural Resource Damage Assessment Approach
Once the Trustee Council is formed, the Trustees will develop an approach for a cooperative natural resource damage assessment and evaluate restoration options to compensate for any identified resource injuries and service losses caused by Bonita Peak Mining District related releases of hazardous substances.

Preassessment Screen
The ONRT will issue a Preassessment Screen and Determination and a Notice of Intent to perform a natural resource damage assessment. To develop the Preassessment Screen, the ONRT is conducting a review of readily available information. Based on this review, ONRT may conclude that various operations at the Site resulted in the release of hazardous substances that have, or are likely to have, injured natural resources and that it was reasonable to proceed with a natural resource damage assessment.