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Dewhirst

Producer in Alameda county in California, United States with commodity Manganese
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Public Land Survey System information
  6. Commodities
  7. Materials information
  8. Nearby scientific data
  9. Ore body information
  10. Economic information about the deposit and operations
  11. Ownership information
  12. Links to other databases
  13. Bibliographic references
  14. General comments
  15. Reporter information

Geologic information

Identification information

Deposit ID 10109081
MRDS ID M004668
Record type Site
Current site name Dewhirst
Related records 10186918

Geographic coordinates

Geographic coordinates: -121.63492, 37.5713 (WGS84)
Elevation 945
Relative position E. SIDE OF CEDAR MOUNTAIN RIDGE, ABOUT 800 FT. N.E. OF A KNOLL

Site location context

Political divisions (FIPS codes)

Alameda(county)

California(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Mendenhall Springs(quadrangle 1:24,000 scale)

Stockton(quadrangle 1:100,000 scale)

San Jose(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

San Francisco Bay(hydrologic unit)

San Francisco Bay(hydrologic accounting unit)

San Francisco Bay(hydrologic subregion)

California(hydrologic region)

Geographic areas

Country State County
United States California Alameda

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 004S 003E 22 California

Comments on the location information

  • LOCATED IN NE 1/4 SW 1/4 SECTION 22

Commodities

Commodity Importance
Manganese Critical Primary

Materials information

Materials Type of material
Glaucophane Gangue

Nearby scientific data

(1) -121.63492, 37.5713
ListMap

Economic information

Ore body information

  • Strike W
    Dip 50 S
    Thickness 0.91M

Comments on the geologic information

  • 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.

Economic information about the deposit and operations

Development status Producer
Commodity type Metallic
Deposit size Small
Significant No

Ownership information

  • Type Owner
    Owner Mabel Newman
    First year 1950

Comments on the production information

  • 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.

Comments on the workings information

  • OPEN CUT, DRIFT FROM WHICH A STOP EXTENDS ALMOST TO THE SURFACE

Reference information

Bibliographic references

  • Deposit

    CALIF. JOUR. MINES & GEOL. V. 46, NO.2, APRIL 1950, P.343, PL. 58

  • Deposit

    DOM BULL. 125, P.98

  • Deposit

    BULL. 152, P.19-20

General comments

Subject category Comment text
Deposit ADD. REF. NO.4. BULL. 140, P.66 PL.1 (GEOLOGY); NO.5. 25TH REPORT OF STATE MINERALOGIST, P. 436

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JUN-1972 Gere, W. U.S. Geological Survey
Updater 01-APR-1977 Von Dohlen, E.; Albers, J. U.S. Geological Survey

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Maps centered on this site

Authoritative California resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.