Mineral Resources and Mineral Hazards

The Mineral Resources and Mineral Hazards Program provides data about California's varied non-fuel mineral resources (such as metals and industrial minerals), naturally occurring mineral hazards (such as asbestos, radon, and mercury), and information about active and historic mining activities throughout the state. Program reports and maps are shared with governmental agencies, universities, repository libraries and are available for purchase from CGS. Older reports are available in paper; some newer reports are available in paper and digital formats compatible with commonly used Geographic Information System (GIS) software. 

The program is divided into two projects: the Mineral Resources Project and the Mineral Hazards Project.

Mineral Resources Project

The CGS Mineral Resources Project provides objective geologic expertise and information about California's diverse non-fuel mineral resources. 

Non-fuel mineral resources fall into three categories: metals, industrial minerals and construction aggregate.

  • Metals include gold, silver, iron and copper.
  • Industrial minerals include boron compounds, rare-earth elements, clays, limestone, gypsum, salt and dimension stone.
  • Construction aggregate includes sand and gravel, and crushed stone.

Maps, reports, and other data products developed by the staff assist governmental agencies, mining companies, consultants, and the public in recognizing, developing, and protecting important mineral resources.

The primary focus of the Mineral Resources Project is to classify lands throughout the state that contain regionally significant mineral resources as mandated by the Surface Mining and Reclamation Act of 1975 (SMARA).​

SMARA Mineral Land Classification Project

In 1975, the California legislature enacted the Surface Mining and Reclamation Act (SMARA). This act provides for the reclamation of mined lands and directs the State Geologist to classify (identify and map) the non-fuel mineral resources of the state to show where economically significant mineral deposits occur and where they are likely to occur based upon the best available scientific data. While reclamation of mined lands falls within the purview of our sibling Division of Mine Reclamation, the process of inventorying the non-fuel mineral resource​s of the state (called "mineral land classification") is a principal responsibility of the Mineral Resources Project.

Since its inception in 1978, the Mineral Land Classification Project has completed 97 classification studies covering about 34% of the state. Thirty two of these studies, covering about 25% of the state, contain resource areas that provide construction aggregate to over 90% of California’s population.

Mineral Resource Data and Reports

Non-fuel mineral resources occur in unique geological settings and, therefore, must be mined where they are found. Although land-use competition between mining and other interests is inevitable, it need not be contentious if adequate planning based on objective and accurate mineral resource data are made available to local land-use planners, elected decision makers, the mining industry, and the public.

The Mineral Land Classification Project provides objective classification maps, technical mineral resource data, and mineral-related economic investigations about economically exploitable non-fuel mineral resources in the state.

The information presented in classification reports is as accurate as is feasible to assemble at the time of the study. Mineral land planning decisions made today will impact future generations. The intent of classification is to assist lead agencies, planners, and the public in the wise use, management, and conservation of California’s mineral resources.

Although all mineral commodities mined in California are studied, special emphasis has been given construction aggregate because it is the state’s most important mineral commodity in terms of tonnage, value, and societal infrastructure. As California’s population continues to expand, the demand for minerals - especially building construction minerals such as aggregate - will similarly grow. Over 90% of these essential construction resources are transported by truck because unit trains and marine transport, although used, are currently uncommon in the state. Because such high-volume low-cost construction minerals are expensive to transport, and in order to minimize the environmental affects of trucking these resources from distant sources, it is beneficial - both economically and environmentally - that sand, gravel, and crushed stone resources be mined in reasonable proximity to growing communities.

Mineral Hazards Project

The Mineral Hazards Project provides maps, technical information and advice, and monitors activities about minerals-related environmental and public health issues such as naturally occurring heavy metals, asbestos, mercury and radon.

Staff often work with other state and federal departments to lend expertise about potential mineral hazards. Current projects underway include:

  • A CALFED​​-funded project to provide information on natural sources of mercury as well as mercury from historic mercury mining activities in the Cache Creek watershed in the Coast Ranges north of San Francisco. 
  • A statewide map of potential asbestos host rocks, per recommendations of the State Air Resources Board (ARB) Asbestos Task Force
  • Pilot project identifying areas more likely to contain naturally occurring asbestos (NOA) in western El Dorado County
    • This project now serves as a statewide model for NOA studies
  • Interagency agreement with Caltrans for data on NOA occurrence , useful in highway construction and maintenance projects. 
    • Includes development of NOA for use in training of Caltrans staff. ​
  • Statewide map and database of radon occurrence​ for California Department of Public Health (CDPH), including completed studies in Santa Barbara and Ventura counties that identified source rocks and soils associated with radon detected in homes and commercial buildings. 
  • Completed studies of radon occurrence in schools in various areas of the state. 
  • Contract with the U.S. Geological Survey (USGS) to provide updated information on certain precious- and base-metal mines throughout the state for use in mineral resource and environmental studies.

Contact Information

Mineral Resources and Mineral Hazards Program
801 K Street, MS 08-38
Sacramento, CA 95814
Phone: (916) 322-2719
Fax: (916) 324-6490
mrmhmp@consrv.ca.gov

Program Supervisor
Fred Gius, Supervising Geologist 
(916) 322-2719
fred.gius@conservation.ca.gov