The O'Brien Mine is a chromium mine located in El Dorado county, California at an elevation of 1,440 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
Elevation: 1,440 Feet (439 Meters)
Commodity: Chromium
Lat, Long: 38.82611, -121.89639
Map: View on Google Maps
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.
O'Brien Mine MRDS details
Site Name
Primary: O'Brien Mine
Secondary: S-Bend Mine
Commodity
Primary: Chromium
Location
State: California
County: El Dorado
District: Garden Valley Area
Land Status
Not available
Holdings
Not available
Workings
Not available
Ownership
Owner Name: Margaret Bell, Grass Valley, Ca
Production
Year: 1942
Time Period: 1918-1942
Material type: ORE
Description: Cp_Grade: ^32-34% Cr2o3
Deposit
Record Type: Site
Operation Category: Past Producer
Operation Type: Unknown
Years of Production:
Organization:
Significant: N
Deposit Size: S
Physiography
General Physiographic Area: Pacific Mountain System
Physiographic Province: Pacific Border Province
Physiographic Section: California Coast Ranges
Physiographic Detail: Sierra Nevada Foothills
Mineral Deposit Model
Not available
Orebody
Form: POD, LENS
Structure
Type: L
Description: A Fault With Considerable Apparent Displacement Is Exposed In Lower Adit And On Surface.
Alterations
Alteration Type: L
Alteration Text: Serpentinization, Chloritization
Rocks
Name: Diorite
Role: Associated
Age Type: Associated Rock Unit
Age Young: Late Cretaceous
Analytical Data
Not available
Materials
Ore: Chromite
Gangue: Talc
Comments
Comment (Workings): WORKINGS CONSIST OF TWO ADITS, A GLORY HOLE, AND A SHALLOW WINZE.
Comment (Location): LOCATED ON STEEP, SE FACING HILLSIDE
Comment (Development): MINE LAST OPERATED 1942 BY VOLO MINING CO.
Comment (Geology): MINE OCCURS IN ULTRAMAFIC MASS EXPOSED IN WESTERN METAMORPHIC BELT OF SIERRA NEVADA FOOTHILLS.
References
Reference (Reserve-Resource): CDMG BULL 134, P. 156.
Reference (Deposit): STINSON, M.C., 1976, MINERAL PROPERTY REPORT, CDMG UNPUBLISHED REPORT.
Reference (Deposit): CDMG BULL 134, PT. 3, CHPT. 4, P. 156
Reference (Production): CDMG BULL 134, P. 156
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.
