Rockfield Mine

The Rockfield Mine is a gold and silver mine located in Larimer county, Colorado at an elevation of 7,959 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: Rockfield Mine
Secondary: Unpatented Claims: Rodkfield
Secondary: Pendergast Tunnel
Secondary: Valentine Lod E
Secondary: Matchless Nos. 1 and 2

Commodity

Primary: Gold
Primary: Silver

Location

State: Colorado
County: Larimer
District: Manhattan District

Land Status

Land ownership: National Forest
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

Owner Name: S. A. And W. T. Pendergast
Home Office: Log Cabin
Years: 1941 -

Production

Not available

Deposit

Record Type: Site
Operation Category: Past Producer
Deposit Type: Vein
Operation Type: Unknown
Year First Production: 1937
Year Last Production: 1941
Discovery Year: 1916
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

Not available

Orebody

Not available

Structure

Type: R
Description: Front Range Uplift, Sherman Batholith

Type: L
Description: Poudre River Shear Zone, Elkhorn Creek Shear Zone

Alterations

Not available

Rocks

Name: Quartz Monzonite
Role: Associated
Age Type: Associated Rock Unit
Age Young: Pliocene

Name: Quartz Monzonite
Role: Associated
Age Type: Host Rock
Age Young: Neoproterozoic

Name: Quartz Monzonite
Role: Associated
Age Type: Associated Rock
Age Young: Pliocene

Analytical Data

Analytical Data: MILLING ORE FROM 1941 REPORTEDLY CONTAINED 18 OZ/TON AU AND 1.5 OZ /TON AG.

Materials

Ore: Pyrite

Comments

Comment (Location): SOUTH OF SEVENMILE CREEK BASED ON BLM RECORD OF PENDERGAST TUNNEL CLAIM RECORD. ELEV AND LAT-LONG GIVEN ARE FOR CENTER SW SEC. 29 ; INFO FROM LAND.ST :1980

Comment (Production): EXPLORATION AND DEVELOPMENT FROM 1923-36; PRODUCTION IN 1937 AND 1 941; NO PRODUCTION IN 1938-40.

Comment (Deposit): AIRPHOTOS INDICATE PROBABLE QUARTZ MONZONITE DIKE TRENDING N76 TO 82E THROUGH METAMORPHICS FROM N2 SE SEC. 30 ACROSS N EDGE OF SW SEC. 29 TO S2 S2 NE SEC. 29.

Comment (Workings): 900-FT CROSSCUT TUNNEL AND SHORT CROSSCUTS; SURFACE TRENCHES

References

Reference (Deposit): LOVERING, T.S., AND GODDARD, E.N., 1950, GEOLOGY AND ORE DEPOSITS O F THE FRONT RANGE, COLORADO: USGS PROF. PAPER 223, P. 285-286

Reference (Deposit): COLORADO DIV. MINES INF. REPT. AND ANNUAL OPERATOR REPT.

Reference (Production): COLORADO DIV. MINES ANN. OPERATOR REPTS.

Colorado Mining Photos

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