TSF supports California’s new recommendation for Abandoned Mine Land cleanup

We are thrilled to see The California Legislative Analyst’s Office (LAO) recently published report “Improving California’s Response to the Environmental and Safety Hazards Caused by Abandoned Mines” which underscores the important work of TSF and project partners to protect public health from legacy mining hazards and advocate for increased investment in projects that work to remediate Abandoned Mine Lands (AMLs).

“This report is a clear statement of public interest in confronting the physical and environmental threats of AMLs. It acknowledges the systematic challenges that we encounter in addressing legacy impacts and gives directions for how to increase the pace and scale of mine remediation for greatest net benefit” says Carrie Monohan Ph.D., Program Director of TSF.

The LAO Report comes over a decade after TSF first elevated the issue of Mining’s Toxic Legacy, in 2008 to a joint hearing of three Assembly Committees: Environmental Safety and Toxic Materials, Natural Resources, and Water, Parks, and Wildlife. Since that time, TSF has led cutting edge pilot projects that identify best available technologies for cleanup of AMLs, held five biennial science and policy conferences addressing Gold Rush era impacts, and developed a regional strategy for identifying, assessing prioritizing, and remediating legacy mine impacts associated with mercury.

“We endorse the LAO recommendations and look forward to working with the legislature and the Newsom administration to enact some of these visionary ideas,” says Elizabeth Martin, CEO of TSF.

As a leading voice for the Sierra Nevada region, TSF is well-poised to move a campaign forward to adopt the actions the Legislative Analyst’s Office calls for in this report – the same actions TSF has been calling for throughout nearly two decades of service to the Sierra Nevada.

To read the full report on the California Legislative Analyst’s Office website, visit https://lao.ca.gov/Publications/Report/4258.


Abandoned Mine Lands (AMLs). remnant from California’s mining history have left behind a legacy of chemical and physical hazards that threaten public health and safety. It is estimated that there are 47,000 abandoned mines in California, many of which are concentrated at the epicenter of the California Gold Rush, the Sierra Nevada region.

The California Gold Rush has left a lasting mark on the Sierra Nevada. Today, the region is riddled with abandoned mine shafts and tunnels—and other dangers that may not be apparent at first glance. The mining and mineral-processing practices of the past were not subject to today’s environmental standards and have resulted in extensive contamination to the land and waters of California.

Using techniques including placer, hard rock, and hydraulic mining, millions of ounces of gold were extracted from the Sierra Nevada “Mother Lode” during the 19th and 20th centuries. Mining practices commonly included extensive use of mercury, which still contaminates the landscape. Abandoned mines have left behind toxic pits and acid mine drainage. Naturally occurring minerals, including arsenic and asbestos, were disturbed, crushed, and distributed throughout the region as gravels for road construction. Much of the land impacted by these activities is now publicly owned by state, federal, and local governments.