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Abandoned Mine Lands

Gold mining in the Sierra Nevada was the catalyst for the rapid growth and development of California. The historic California Gold Rush, beginning in 1849, brought a rapid increase in the population of the State, contributing to the growth of cities and communities within and outside the Region and changing our landscapes and waterways. The remnants of the historic Gold Rush and mining activities of the past are still with us today in many forms including historic mining communities and features, such as mine shafts, tunnels, and open scars on the land and water conveyances. There are other aspects of our mining legacy that are more difficult to see. Toxic substances associated with legacy mining, in particular mercury, have far reaching impacts to water quality and water supply. These toxic substances are carried within the waterways of the Region downstream to water storage facilities, the Sacramento-San Joaquin Bay Delta and the San Francisco Bay.


Mining activities from the past found on abandoned mine lands have the potential to impact the residents of the Sierra Nevada and the State of California in the following ways:

  • Water quality impairment and health impacts from toxic substances - mercury is of particular concern;
  • Sedimentation impacting waterways and storage facilities; and,
  • Physical hazards to people and animals from abandoned mine features.

The Sierra Nevada contains a large volume of the 47,000 identified abandoned mines in the state. The SNC is committed to working with our partners and other state and federal agencies to:

  • Support efforts to reduce the amount of mercury within the Region’s waterways, thereby reducing impacts to downstream populations and communities.
  • Assess existing programs and investigate the potential for new programs to address AML issues and seek opportunities to leverage these efforts on behalf of the Sierra.
  • Continue and build upon ongoing efforts to increase awareness and understanding of AML issues and the importance of remediation.

Successful remediation of the problems associated with AMLs in the Sierra Nevada Region will benefit water quality and water reliability throughout California.

Download our Abandoned Mine Lands Fact Sheet.

California Abandoned Mine Lands Prioritization Tool

The SNC in partnership with the Department of Conservation and the University of California, Davis, and members of the multi-agency California Abandoned Mine Lands Agency Group (CAMLAG) have developed Phase 1 of the California Abandoned Mine Lands Prioritization Tool (CAMPT). Phase 1 CAMPT provides a solid foundation for the next phase: full implementation of a statewide, multi-agency accessible tool.