The Keystone Group is a copper mine located in Inyo county, California.
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.
Keystone Group MRDS details
Site Name
Primary: Keystone Group
Secondary: Darwin-Keystone
Commodity
Primary: Copper
Secondary: Lead
Secondary: Silver
Secondary: Gold
Location
State: California
County: Inyo
District: Darwin
Land Status
Not available
Holdings
Not available
Workings
Not available
Ownership
Not available
Production
Year: 1941
Time Period: 1940 - 1941
Material type: ORE
Description: Ap_Grade: ^.04 Oz Au/Ton, 27.9 Oz Ag/Ton, 25 % Pb, .6 % Zn, 20 % Iron.
Deposit
Record Type: Site
Operation Category: Past Producer
Deposit Type: Vein
Operation Type: Unknown
Years of Production:
Organization:
Significant: N
Deposit Size: S
Physiography
Not available
Mineral Deposit Model
Not available
Orebody
Not available
Structure
Type: L
Description: Folds, Faults
Alterations
Not available
Rocks
Not available
Analytical Data
Not available
Materials
Ore: Galena
Gangue: Limonite
Gangue: Jasper
Gangue: Calcite
Comments
Comment (Production): REPORTED: 800 TONS OF SORTED ORE SHIPPED FROM LOWER WINZE AND ZONE BETWEEN THE TWO WORKINGS, ORE AVERAGED 15 % PB, 28 OZ AG/TON, MINOR GOLD.
Comment (Workings): LOWER WORKINGS; KEYSTONE ADIT, 626 FT. LONG, DRIFT 210 FT. LONG, 120 FT. OF CROSSCUTS, A 175 FT. STEEPLY INCLINED WINZE, SMALL STOPES. UPPER WORKINGS; MCDONALD ADIT. CAVED 145 FT. FROM PORTAL, 135 FT. OF DRIFTS, MINOR CROSSCUTS.
Comment (Geology): GEOL.DESC: MINE IS ON FOLDED AND FAULTED ROCK OF KEELER CANYON FORMATION. ROCKS ARE BROWN-WEATHERING SILTY LIMESTONE AND BLUE-GRAY LIMESTONE. LIMESTONE IS PARTLY ALTERED TO CALC-HORNFELS. DOMINANT FAULTS TREND BETWEEN N 70 E AND EAST, DIP STEEPLY.
Comment (Deposit): ORE IS HIGHLY OXIDIZED - POORLY EXPOSED, 2 - 10 FT. THICK. HAS BEEN EXPLOITED FOR STRIKE LENGTH OF 40 FT. UNDERGROUND.
References
Reference (Production): HALL & MACKEVETT, 1958 , P. 32 (SEE REF.)
Reference (Deposit): HALL, W. E. AND MACKEVETT, E. M., 1958 , ECONOMIC GEOLOGY OF THE DARWIN QUADRANGLE, INYO COUNTY, CALIFORNIA; DIV. OF MINES, SPECIAL REPORT 51 ; P. 31 - 32
California Gold
"Where to Find Gold in California" looks at the density of modern placer mining claims along with historical gold mining locations and mining district descriptions to determine areas of high gold discovery potential in California. Read more: Where to Find Gold in California.
