Adeline
California · Calaveras County
Unconfirmed Gold Past Producer Underground
Historical mapped workings available
Underground
Records whose USGS work type documents underground workings. · 3432 records
In mining terminology, underground workings are excavations accessed by shafts, adits, tunnels, or inclines beneath the surface.
Many USGS MRDS records state “Underground” without naming a specific shaft or adit. UndergroundMines preserves that distinction rather than inventing feature types.
Adjust Mine
Arizona · Pinal County
Unconfirmed Lead Producer Underground
Documented shaft evidence
Advance
California · Alpine County
Unconfirmed Silver Past Producer Underground
Historical mapped workings available
Advance Consolidated
California · Shasta County
Unconfirmed Gold Past Producer Underground
African Prospect
Arizona · Mohave County
Unconfirmed Gold Occurrence Underground
Historical mapped workings available
After Thought
California · Calaveras County
Unconfirmed Gold Past Producer Underground
Documented shaft evidence
Afterthought
California · Shasta County
Unconfirmed Copper Past Producer Underground
Historical mapped workings available
Ajax
California · Shasta County
Unconfirmed Gold Past Producer Underground
Ajax Mine
Arizona · Pinal County
Source Corroborated Lead Producer Underground
Documented shaft/adit evidence
Akers Group
California · Shasta County
Unconfirmed Copper Past Producer Underground
Akron Claim
Nevada · Clark County
Mindat Confirmed Zinc Past Producer Underground
Documented shaft evidence
Al and Hal Mine
Arizona · Gila County
Unconfirmed Copper Producer Underground
Historical mapped workings available
Al Mono
California · Mono County
Unconfirmed Gold Past Producer Underground
Alabama
California · Placer County
Unconfirmed Gold Past Producer Underground
Documented shaft evidence
Alabama
California · Tuolumne County
Unconfirmed Gold Producer Underground
Documented shaft/adit evidence
Alabaster Cave
California · El Dorado County
Unconfirmed Copper Past Producer Underground
Aladdin Group
Nevada · Elko County
Unconfirmed Copper Past Producer Underground
Historical mapped workings available
Alameda
California · Mariposa County
Unconfirmed Gold Past Producer Underground
Documented adit evidence
Alameda
California · Tuolumne County
Unconfirmed Gold Past Producer Underground
Documented shaft/adit evidence
Alarid Prospect
California · Mariposa County
Unconfirmed Gold Past Producer Underground
Historical mapped workings available
Alaska
California · Sierra County
Unconfirmed Gold Past Producer Underground
Historical mapped workings available
Alaska
California · Nevada County
Unconfirmed Gold Past Producer Underground
Alaska Mine
Arizona · Yavapai County
Unconfirmed Gold Producer Underground
Documented shaft evidence
Alaskan Mine
Arizona · La Paz County
Unconfirmed Gold Past Producer Underground
Documented adit evidence