The Dewhirst is a manganese mine located in Alameda county, California at an elevation of 3,100 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: 3,100 Feet (945 Meters)
Commodity: Manganese
Lat, Long: 37.57139, -121.63389
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.
Dewhirst MRDS details
Site Name
Primary: Dewhirst
Commodity
Primary: Manganese
Location
State: California
County: Alameda
Land Status
Not available
Holdings
Not available
Workings
Not available
Ownership
Owner Name: Mabel Newman
Years: 1950 -
Production
Not available
Deposit
Record Type: Site
Operation Category: 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
Mineral Deposit Model
Not available
Orebody
Not available
Structure
Not available
Alterations
Not available
Rocks
Not available
Analytical Data
Not available
Materials
Gangue: Glaucophane
Comments
Comment (Workings): OPEN CUT, DRIFT FROM WHICH A STOP EXTENDS ALMOST TO THE SURFACE
Comment (Location): LOCATED IN NE 1/4 SW 1/4 SECTION 22
Comment (Geology): GEOL.DESC: LENTICULAR ORE BODY OF SILICEOUS ORE UNDERLAIN CONFORMABLY BY 5 FT OF MASSIVE WHITE CHERT CONTAINING A FEW STREAKS OF MANGANESE OXIDE THAT RUN PARALLEL TO BEDDING. ABOVE ORE BODY ARE ABOUT 3 FT. OF MASSIVE CHERT WITH OCCASIONAL OBSCURE PARTINGS DUE TO THIN FILMS OF SHALE. THE ORE BODY AND MASSIVE CHERT ARE CUT BY NUMEROUS QUARTZ VEINS AND LIE ESSENTIALLY PARALLEL TO THE ENCLOSING THIN BEDDED CHERTS. THE MASSIVE CHERT ABOVE THE ORE BODY CONTAINS SMALL VEINLETS AND IMPREGNATIONS OF A BLUE AMPHIBOLE RESEMBLING GLAUCOPHANE.
Comment (Deposit): ADD. REF. NO.4. BULL. 140, P.66 PL.1 (GEOLOGY); NO.5. 25TH REPORT OF STATE MINERALOGIST, P. 436
Comment (Production): ABOUT 30 TONS OF ORE HAS BEEN EXTRACTED AND A SACKED FOR SHIPMENT. THIS MATERIAL IS ESTIMATED TO RUN OVER 20 PERCENT SILICA. THE ORE CONTAINS ABOUT 40 PERCENT MANGANESE AND 15-20 PERCENT SILICA.
References
Reference (Deposit): CALIF. JOUR. MINES & GEOL. V. 46, NO.2, APRIL 1950, P.343, PL. 58
Reference (Deposit): DOM BULL. 125, P.98
Reference (Deposit): BULL. 152, P.19-20
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.
