Boulder Mine

The Boulder Mine is a silver mine located in Custer county, Colorado at an elevation of 8,051 feet.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

Satelite View

MRDS mine locations are often very general, and in some cases are incorrect. Some mine remains have been covered or removed by modern industrial activity or by development of things like housing. The satellite view offers a quick glimpse as to whether the MRDS location corresponds to visible mine remains.

Site Name

Primary: Boulder Mine
Secondary: Boulder-Buffalo

Commodity

Primary: Silver
Secondary: Manganese
Secondary: Iron

Location

State: Colorado
County: Custer
District: Silver Cliff

Land Status

Land ownership: BLM Administrative Area
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.

Holdings

Not available

Workings

Type: Surface

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Past Producer
Operation Type: Surface
Discovery Year: 1895
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

General Physiographic Area: Rocky Mountain System
Physiographic Province: Southern Rocky Mountains

Mineral Deposit Model

Model Name: Epithermal veins

Orebody

Not available

Structure

Type: R
Description: Silver Cliff Volcanic Center, Wet Mtns, Wet Mtn Valley

Type: L
Description: Large Nw-Trending Fault

Alterations

Alteration Type: L
Alteration: argillic
Alteration Text: Weak Argillization

Rocks

Name: Clay, Mud
Role: Associated
Age Type: Associated Rock Unit
Age Young: Oligocene

Name: Clay, Mud
Role: Associated
Age Type: Associated Rock
Age Young: Oligocene

Name: Clay, Mud
Role: Associated
Age Type: Host Rock
Age Young: Miocene

Analytical Data

Not available

Materials

Ore: Cerargyrite
Ore: Psilomelane
Ore: Ocher
Gangue: Kaolin

Comments

Comment (Location): NE OF GEYSER MINE NORTH OF UNNAMED TRIBUTARY TO CHLORIDE GULCH ; INFO FROM LAND.ST :(1976)

Comment (Development): THE BOULDER AND BUFFALO HUNTER MILL WAS ERECTED TO TREAT ORES FROM BOTH MINES

Comment (Workings): SEVERAL CUTS

Comment (Geology): ORE OCCURS IN CONCENTRIC SHELLS SURROUNDING SPHERULITES IN PARTLY DECOMPOSED ZONE

References

Reference (Deposit): CROSS, WHITMAN, 1896, GEOLOGY OF SILVER CLIFF AND THE ROSITA HILLS, COLORADO: USGS 17TH ANN. REPORT, PT 2, P. 263-403.

Reference (Deposit): EMMONS, S.F., 1896, THE MINES OF CUSTER COUNTY, COLORADO: USGS 17TH ANN. REPORT, PT 2, P. 405-472.

Reference (Deposit): SHARP, W.M., 1978, GEOLOGIC MAP OF THE SILVER CLIFF AND ROSITA VOLCANIC CENTERS, CUSTER COUNTY, COLORADO: USGS MAP I-1081.

Colorado Mining Photos

Check out this collection of Colorado's best historic mining photos: Incredible Photos of Colorado Mining Scenes.