Alto Mine
California · Calaveras County
Unconfirmed Gold Producer Mixed Underground/Surface
Documented shaft/adit evidence
Mixed Underground / Surface
Records documenting both surface and underground work. · 1280 records
Mixed surface/underground sites may include open cuts, pits, or glory holes alongside shafts or levels.
Catalog eligibility still requires underground evidence; surface-only properties are not treated as underground mines.
Altoona Mine
California · Trinity County
Unconfirmed Mercury Past Producer Mixed Underground/Surface
Documented shaft/adit evidence
American
California · Santa Clara County
Unconfirmed Mercury Past Producer Mixed Underground/Surface
Historical mapped workings available
American Canyon Placers
Nevada · Pershing County
Unconfirmed Gold Past Producer Mixed Underground/Surface
Historical mapped workings available
American Eagle
California · Mariposa County
Unconfirmed Copper Past Producer Mixed Underground/Surface
Historical mapped workings available
American Fiber Co.
Arizona · Gila County
Unconfirmed Asbestos Past Producer Mixed Underground/Surface
Documented adit evidence
American Girl Mine
California · Imperial County
Unconfirmed Gold Plant Mixed Underground/Surface
Historical mapped workings available
American Manganese Mine
Arizona · Gila County
Unconfirmed Manganese Past Producer Mixed Underground/Surface
Historical mapped workings available
American Prospect
Arizona · Mohave County
Unconfirmed Manganese Occurrence Mixed Underground/Surface
Anaco
California · San Bernardino County
Unconfirmed Zinc Occurrence Mixed Underground/Surface
Anderson Springs
California · Lake County
Unconfirmed Mercury Past Producer Mixed Underground/Surface
Historical mapped workings available
Angels Mine
California · Calaveras County
Unconfirmed Gold Past Producer Mixed Underground/Surface
Historical mapped workings available
Annie Laurie
California · Placer County
Unconfirmed Gold Past Producer Mixed Underground/Surface
Historical mapped workings available
Antelope Prospect
Nevada · Nye County
Unconfirmed Mercury Past Producer Mixed Underground/Surface
Antimony King Mine
Nevada · Churchill County
Unconfirmed Antimony Producer Mixed Underground/Surface
Historical mapped workings available
Antimony King Mine
Nevada · Lander County
Unconfirmed Antimony Past Producer Mixed Underground/Surface
Documented adit evidence
Apache & Dulcy Claims
Arizona · Maricopa County
Unconfirmed Manganese Past Producer Mixed Underground/Surface
Historical mapped workings available
Apache Manganese Mine
Arizona · Gila County
Unconfirmed Manganese Past Producer Mixed Underground/Surface
Historical mapped workings available
Apex No. 1 Claim
Nevada · Humboldt County
Unconfirmed Gold Occurrence Mixed Underground/Surface
Historical mapped workings available
Arcturus Mine
Nevada · Pershing County
Unconfirmed Tungsten Occurrence Mixed Underground/Surface
Documented adit evidence
Argo Pioneer
California · Mariposa County
Unconfirmed Gold Past Producer Mixed Underground/Surface
Documented shaft evidence
Argonaut
California · El Dorado County
Unconfirmed Gold Past Producer Mixed Underground/Surface
Documented adit evidence
Arizona Central Mine
Arizona · Greenlee County
Unconfirmed Copper Producer Mixed Underground/Surface
Historical mapped workings available
Arizona Commercial Mine
Arizona · Gila County
Unconfirmed Copper Past Producer Mixed Underground/Surface
Historical mapped workings available