Mason Mine

The Mason Mine is a tungsten, silver, and gold mine located in Larimer county, Colorado at an elevation of 5,719 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: Mason Mine
Secondary: Mason Ranch Mine

Commodity

Primary: Tungsten
Primary: Silver
Primary: Gold

Location

State: Colorado
County: Larimer
District: Masonville District

Land Status

Land ownership: Federal
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

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Producer
Deposit Type: Vein
Operation Type: Unknown
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

General Physiographic Area: Interior Plains
Physiographic Province: Great Plains Province
Physiographic Section: Colorado Piedmont

Mineral Deposit Model

Not available

Orebody

Not available

Structure

Type: R
Description: Front Range Uplift, Cheyenne Basin

Type: L
Description: Big Thompson Anticline, Milner Mountain Fault, Fletcher Hill (Buck Horn) Fault, Masonville Anticline, Buckhorn Syncline, Masonville Stock , Redstone Fault

Alterations

Alteration Type: L
Alteration Text: Hydrothermal Montmorillonite In Fractures

Rocks

Name: Tonalite
Role: Associated
Age Type: Host Rock
Age Young: Neoproterozoic

Name: Tonalite
Role: Associated
Age Type: Associated Rock
Age Young: Neoproterozoic

Name: Tonalite
Role: Associated
Age Type: Associated Rock Unit
Age Young: Neoproterozoic

Analytical Data

Analytical Data: HIGHER GRADE AU ORE IN SHAFT ASSAYED 2 OZ/TON AU.
Analytical Data: VEIN ASSAYED 0.02 TO 0.04 OZ/TON AU, 0.4 TO 0.6 OZ/TON AG

Materials

Ore: Scheelite
Ore: Pyrite
Gangue: Quartz
Gangue: Montmorillonite
Gangue: Hematite
Gangue: Epidote

Comments

Comment (Location): ON HILLSIDE ABOVE BUCKHORN CREEK 0.9 MILE NNW FROM MASONVILLE. ; INFO FROM LAND.ST :1980

Comment (Development): SHAFT ORIGINALLY PENETRATED SCHEELITE WHICH WAS THROWN ON DUMP. S HAFT FLOODED BEFORE HIGHER GRADE AU ORE COULD BE WORKED. CROSSCUT TUNN EL DRIVEN FROM BELOW TO WORK DEPOSIT.

Comment (Workings): MINE DEVELOPED BY 122-FT INCLINED SHAFT, 960-FT ADIT WITH 200 FT OF DRIFTS.

Comment (Deposit): NW-TRENDING FRACTURES CONTAINED EITHER MONTMORILLONITE OR MONTMOR ILLONITE-EPIDOTE-HEMATITE-QUARTZ. MOST NE-TRENDING FRACTURES CONTAINED MONTMORILLOMITE-OR MONTMORILLONITE-EPIDOTE. PYRITE CONCENTRATIONS FOUN D AT SLIGHT CHANGES IN STRIKE ALONG N30E-TRENDING FRACTURE

References

Reference (Deposit): BRADDOCK, W.A., AND OTHERS, 1970, GEOLOGIC MAP OF THE MASONVILLE QU ADRANGLE, LARIMER COUNTY, COLORADO: USGS MAP GQ-832.

Reference (Deposit): COBB, H.S., 1960, TUNGSTEN MINES OF COLORADO: COLORADO METAL MINING FUND BD., P. 49.

Reference (Deposit): WOLFE, J.A., 1953, GEOLOGY OF THE MASONVILLE MINING DISTRICT, LARIM ER COUNTY, COLORADO: COLORADO SCHOOL OF MINES M.SC. THESIS T-789.

Reference (Deposit): BELSER, CARL, 1956, TUNGSTEN POTENTIAL IN CHAFFEE, FREMONT, GUNNISO N, LAKE, LARIMER, PARK, AND SUMMIT COUNTIES, COLORADO: USBM IC-7748, P . 18.

Colorado Mining Photos

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