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Frequently Asked Questions



What is the CA AML Program?
As the Golden State, California has an extensive history of mining for precious metals and minerals, including the largest gold rush in American history.  The impact of historic mining resulted in a substantial legacy of abandoned mines statewide.  California’s AML program is a cooperative conservation program that remediates abandoned hard rock mines containing contaminated mine tailings and physical safety hazards such as open mine shafts.  The California AML program activities are funded in the range of $3-$4 million annually.  ARRA funding stimulated the program with approximately $8.8 million in 2010.

What is the objective of the AML program?
The AML program’s overall objective is to support core BLM programs by mitigating physical safety hazards at abandoned mine land sites on or affecting BLM-managed lands, and by remediating the impacts of contaminated mine waste on water quality and the environment.

How many AML sites are there?
In California it is estimated that there are approximately 50,000 abandoned mines, and about 18,000 of these abandoned mines are believed to be located on BLM-managed lands. Over 3,000 of these sites contain hazardous mine openings and 1,000 likely impact water quality.

California AML Program Accomplishments
- 3,400 AML’s have been evaluated or characterized since 2005; 1080 characterized in 2010.
- 750 physical safety hazards secured since 2005; 293 remediated in 2010.
- 26 AML’s remediated for water quality since 2005; 14 remediated/evaluated in 2010. 

What hazards are associated with AML sites?
- Environmental hazards: Contaminated mine tailings that contain mercury, arsenic and/or acid mine drainage threaten water supplies, communities and habitat.

  • Current Project – The Deer Creek AML cleanup project located in the Nevada City area is currently undergoing a study to investigate the impacts of historic mining and associated contamination of mercury on BLM lands.  The Sierra Fund is a partner on this project.

- Physical hazards: Unsecured AML sites pose a risk of death or serious injury resulting
from falls down open mine shafts.

  • Current Project – Physical safety hazard remediation work performed by the California Department of Conservation as part of an Assistance Agreement with BLM during the first half of FY11 included closing approximately 110 AML features in the Johannesburg/Randsburg area of the California Desert.

How are sites selected as priorities?
BLM’s highest priorities are for areas with AML sites located in close proximity to populated places (e.g. schools, subdivisions, recreational areas, communities) and high use areas such as roads and trails.   The strategy for the CA AML program is to remediate all physical safety hazard features within one-quarter mile of a populated place.  This work is approximately 30% complete. 

Our partners are integral to the success of the AML program. We work with over 20 federal, state, and local partners as well as private organizations to help us achieve our goals. The Department of Conservation - Office of Mine Reclamation assists the program in our inventory efforts as well as providing expertise in securing physical safety hazards. Other partners include the U.S. Geological Survey, U.S. Army Corp of Engineers, National Park Service, and the U.S. Forest Service, State regional water boards, and mining companies.

Budget and Funding Needs
Over the past ten years the California AML program has received more than $30 million dollars. In fiscal year 2010 the AML program received over $12 million dollars. The combined cost to address the large environmental AML sites such as the Rand Historic Mining District will require over $100 million dollars. In addition, the inventory and physical safety hazard securitization will require over $30 million dollars in funding.




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