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TOMS:  Topographically Occurring Mine Symbols


In 1998, the Office of Mine Reclamation began inventorying abandoned mined lands as part of a program to produce a report describing the "scope and magnitude" of abandoned mine issues in California. To support this effort, the Office began digitizing mining features from scanned USGS topographic quadrangles. Each of the 7.5-minute USGS topographic quadrangles was examined and all mining features were digitized and annotated with information derived from the map. Positional accuracy was reliant on the accuracy of the original source maps. Human digitization of the mining symbols has likely added slight deviations from the original source map, though no formal method has been undertaken to quantify this additional error. In 2001, we completed the digitizing process for all 7.5-minute topographic quadrangles covering the state.

The Office of Mine Reclamation is pleased to be able to release these data for public use. We hope the data will prove to be a valuable resource to other government agencies and interested parties working towards the reclamation of California's abandoned mine lands. However, the State of California, Department of Conservation makes no warranty, express or implied, as to the accuracy of these data nor the suitability of the data for any particular use. Distribution of these data is intended for informational purposes and should not be considered authoritative or relied upon for navigation, engineering, legal, or other site-specific uses, including but not limited to the obligations of sellers of real property and their disclosure obligations under California law.

Spatial Data

The spatial data are available as a set of ESRI shapefiles compressed in a ZIP archive file (approx. 3.6 mb). The archive contains shapefiles for point, line and polygon features. Additionally, as a convenience, an ArcView legend file is provided for each shapefile. The archive also contains this html file, FGDC metadata, and the textual metadata for the scanned digital raster graphics (DRG's) that were the source for the "TOMS" data set. FGDC metadata are included for all the formats listed below.

The Department makes no warranty of any kind, express or implied, nor assumes any legal liability or responsibility for the integration of the information, programs or software into any other personal or private computer system or hardware. The user of this information assumes any and all risks and understands that this information is provided on an “as is” basis. All warranties of any kind, express or implied, including but not limited to the implied warranties of merchantability, fitness for a particular purpose, freedom from contamination by computer viruses, and non-infringement of proprietary rights are disclaimed.

        Note: If you want information on the location of abandoned mines, but don't have the necessary software to view
        the TOMS data set, either of the following easy-to-use websites may have information:


Several variants of metadata are available:

Reporting Errors

If you have found errors of omission or comission in these data sets, you may send a report to the Office of Mine Reclamation. Please include the following information:

  • A subject line clearly referencing the "TOMS" data set.

  • The name of the quandrangle(s) where the error was found.

  • The "QUADCODE" for the quadrangle(s) where the error was found.

  • A brief description of the error

  • Your name, address, affiliation, telephone and email so that we may contact you if we have questions

Contact Information

Office of Mine Reclamation
Abandoned Mine Lands Unit
801 K St., MS 09-06
Sacramento, CA 95814

Telephone: (916) 323-9198

National Association of Abandoned Mine Programs | California Geological Survey | State Mining & Geology Board
Department of Toxic Substances Control | California State Lands Commission
Bureau of Land Management | Mine Safety & Health Administration
Office of Surface Mining |  | U.S. Environmental Protection Agency 
U.S. Forest Service | U.S. Geological Survey