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Welcome to the Abandoned Mine Lands Unit

About US

A core team of geologists and scientists that compile a statewide database of abandoned mines and remediate public safety hazards posed by these mines.  Remediation projects are accomplished by working with local, regional, state, and federal partners and can utilize registered geologists, revegetation specialists, and environmental planners from within OMR. The AMLU was created in 1997 to prepare a report to the governor and legislature on the "magnitude and scope" of the abandoned mine lands issue in California. This report was completed in June 2000 and is available electronically on this website (please click here).

California Abandoned Mine Lands Program Fact Sheets (PDF)

The AMLU's work has been recognized with the Fix A Shaft Today! Award from the federal Bureau of Land Management.  For more information, click here


California AML Information

AMLU estimates of the number of abandoned mines in California include the following:

  • Approximately 165,000 mine features* on more than 47,000 abandoned mine sites exist statewide.

  • More than 39,400 abandoned mines (84 percent of 47,000 sites) present physical safety hazards, and approximately 5,200 (11 percent) present environmental hazards.

  • More than 62,000 abandoned mine features (38 percent of 165,000 features) are hazardous openings.

  • Federal lands contain approximately 67 percent of the abandoned mines in the State (primarily on Bureau of Land Management, National Park Service, and U.S. Forest Service property). Approximately 31 percent are on private lands, and about 2 percent are on State or local lands.

    * A feature is a single human-made object or disturbance associated with mining, such as a shaft or adit (vertical or horizontal opening), tailings, machinery and facilities, etc. A mine can be comprised of one or more features.

For a statewide map showing California abandoned mines, including remediated, inventoried and U.S. Geological Survey mapped mine feature locations, please click here.

Stay Out, Stay Alive!

We have a toll free number, 877-OLD-MINE, that the public may call to report abandoned mines. While we try to perform field visits to reported sites as soon as possible, resource constraints and other obligations limit the availability of staff.

Additional "Stay Out, Stay Alive" information is available on the website of the federal Mine Safety and Health Administration (MSHA).

AMLU Inventories

Since 1997, the AMLU has conducted field inventories of more than 57,000 mine features on more than 4,200 abandoned mine sites on public and private lands in California.  This field inventory program is designed to accurately locate abandoned mines and to provide a preliminary assessment of any health and safety hazards observed.  

AMLU remediations

Since 2002, the AMLU has helped to remediate more than 1,300 hazardous abandoned mine features, in partnership with more than two dozen local, state and federal partners.  Most AMLU projects involve the remediation of physical hazards. Techniques to remediate hazardous mine openings and associated debris include:  wire fencing; backfills; polyurethane foam (PUF) closures; bat-compatible gates, cupolas, and culvert gates; other closures, including blasting shut, fitting with concrete plugs or steel caps, etc.; demolition of unstable structures; and removal of hazardous debris and trash.  All work is conducted in accordance with California Environmental Quality Act (CEQA) or National Environmental Policy Act (NEPA) environmental reviews, which are performed by the land-owning agencies.

To see some examples of AMLU Remediations, please click here.
For a list of remediation partners, click

California Abandoned Mine Lands Forum

The Department of Conservation convenes the California Abandoned Mine Lands Forum to provide a venue for discussion and coordination on water quality, safety and environmental hazard issues that agencies and other groups face with their abandoned mine land remediation projects in California.  For schedules, agendas, minutes, and charter, click here.






Principal Area of Mine Pollution (PAMP) & Topographically Occuring Mine Symbols (TOMS)

        To request the PAMP and TOM datasets please contact:    
            Sarah Reeves
            Engineering Geologist