Mining’s Toxic Legacy

The Sierra Fund’s report Mining’s Toxic Legacy is the first comprehensive evaluation of what happened during the Gold Rush. This 85-page report, published in March 2008, includes: the cultural, health, and environmental impacts of the 19th century extractive era; the obstacles that lie in the way of addressing these impacts; and a strategic plan of action for cleaning up the Sierra Nevada, the headwater source of more than 60% of California’s drinking water.

The Gold Rush changed California demographics as indigenous people were dislocated and mining towns appeared and disappeared across the Sierra Nevada Mountains. A less recognized consequence of the California Gold Rush was the massive environmental destruction that took place, which still plagues the Sierra today.

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Mining’s Toxic Legacy discusses the environmental impacts of historic mining techniques, such as using hydraulic monitors to wash away the sides of mountains, or hard rock mines that dug hundreds of miles of tunnel through rock. It documents the widespread distribution of contamination associated with mining, including mercury used for gold mining, and naturally occurring toxic minerals such as arsenic and asbestos in mine tailings that were crushed and redistributed throughout the region.


This report was created from over two years of research and review, working with partners from state, federal, and tribal governments as well as from the academic, health, and environmental communities. The purpose of this report is to present information on the nature and extent of mining toxics in the Sierra, the problems they pose to human and environmental health, and recommendations for action to address these problems. This is accomplished by examining the best available science from the perspective of communities in the Gold Country, and directing the results to regional nonprofit organizations and local, state, federal, and tribal governments.


The Sierra Fund 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 Abandoned Mine Lands, held five biennial science and policy conferences addressing Gold Rush era impacts, and developed a regional Headwater Mercury Source Reduction strategy for identifying, assessing, prioritizing, and remediating legacy mine impacts associated with mercury.

Next Steps

The California Legislative Analyst’s Office (LAO) August 2020 report “Improving California’s Response to the Environmental and Safety Hazards Caused by Abandoned Mines” underscores the important work of The Sierra Fund and project partners to protect public health from legacy mining hazards and advocates for increased investment in projects that work to remediate Abandoned Mine Lands (AMLs). Sound policies and programs that support the remediation of AMLs in the headwaters are critical for ensuring there is the funding and the will to address Mining’s Toxic Legacy. The Sierra Fund will meet with state leadership to forge partnerships leading to the implementation of recommendations cited by the LAO report.

Project Funders

Rose Foundation for Communities and the Environment
The Abandoned Mine Alliance