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Pocohontas

Past Producer in Mariposa county in California, United States with commodities Copper, Gold, Silver
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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. Alteration
  9. Host and associated rocks
  10. Nearby scientific data
  11. Ore body information
  12. Controls for ore emplacement
  13. Economic information about the deposit and operations
  14. Ownership information
  15. Production statistics
  16. Links to other databases
  17. Bibliographic references
  18. General comments
  19. Reporter information

Geologic information

Identification information

Deposit ID 10031051
MRDS ID M009622
Record type Site
Current site name Pocohontas

Geographic coordinates

Geographic coordinates: -120.06431, 37.3441 (WGS84)
Elevation 610
Relative position NW 1/4 SEC. 12 , 1 MILE NORTH OF WHITE ROCK SCHOOL

Site location context

Political divisions (FIPS codes)

Mariposa(county)

California(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Illinois Hill(quadrangle 1:24,000 scale)

Merced(quadrangle 1:100,000 scale)

San Jose(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Fresno River(hydrologic unit)

San Joaquin(hydrologic accounting unit)

San Joaquin(hydrologic subregion)

California(hydrologic region)

Geographic areas

Country State County
United States California Mariposa

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 007S 017E 01,12,14 California

Commodities

Commodity Importance
Copper Primary
Gold Secondary
Silver Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrite Ore
Pyrrhotite Ore
Sphalerite Ore
Quartz Gangue

Alteration

  • (Local) Hydrothermal

Analytical data

Result 6 - 12 % CU, $2.50/TON AU ( 1902 PRICE

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Schist

Nearby scientific data

(1) -120.06431, 37.3441
ListMap

Economic information

Ore body information

  • General form LENTICULAR
    Strike N 35 - 45 W
    Dip 65 - 80 NE

Controls for ore emplacement

  • Shear Zone

Comments on the geologic information

  • GEOL.DESC: WALL ROCKS CONSIST PRINCIPALLY OF QUARTZ - BIOTITE HORNFELS, QUARTZ - BIOTITE AND QUARTZ - BIOTITE - ANDALUSITE SCHIST. ALONG MINERALIZED ZONE, A SHEET OF HORNBLENDE RICH GRANITIC ROCK INTRUDED PARALLEL TO SCHISTOSITY. THIN SHEETS OF BIOTITE QUARTZ DIORITE PENETRATE SCHIST NEAR MINE OPENINGS. A STOCK OF BIOTITE QUARTZ DIORITE CROPS OUT LESS 400 FT. SE. OF MAIN SHAFT.

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Deposit size Medium
Significant No
Discovery year 1862
Production years 1902 - 1913

Ownership information

  • Type Operator
    Owner Eben N. Briggs (Estate)
    Home office C/O L. M. Olds

Production statistics

  • Year 1916
    Material ORE
    Accuracy Accurate
    Description Ap_Grade: ^Avg. 2.8% Cu
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Copper Copper 3wt-pct

Comments on the production information

  • $30,000 CU IN A THREE - YEAR PERIOD IN EARLY 1900'S.

Comments on the reserve resource information

  • ESTIMATION NOT POSSIBLE DUE TO CONDITIONS OF MINE WORKINGS. NUMEROUS GOSSAN OUTCROPPINGS, AND SHEAR ZONES PARALLEL TO PRINCIPAL ORE ZONE HAVE NOT BEEN THOROUGHLY PROSPECTED. NO INDICATIONS OF LOWERING IN THE GRADE OF ORE WITH DEPTH.

Comments on the workings information

  • WORKINGS AS OF 1954 : 7 SHAFTS FROM 15 - 75 FT. DEEP AND TUNNEL DRIVEN NW. MOST SHAFTS INCLINED STEEPLY SE.

Reference information

Bibliographic references

  • Deposit

    BOWEN, O. E. AND CLIFFTON, G. H., 1957 , MINES AND MINERAL RESOURCES OF MARIPOSA COUNTY, CALIFORNIA, CALIF. JOUR. MINES AND GEOLOGY, VOL. 53 , NO. 1 & 2 , P. 67 - 69 , P. 230 .

  • Deposit

    ERIC, J. H., 1948 , COPPER IN CALIFORNIA BULL. 144 ; DIV. OF MINES, P. 269 .

  • Production

    BOWEN, AND CLIFFTON, 1957 , P. 68 (SEE REF.)

General comments

Subject category Comment text
Deposit Discovery Year: EARLY 1860'S
Deposit SULFIDE ORE OCCURS IN A GANGUE OF BRECCIATED WALL ROCK AND INTRODUCED QUARTZ. ONE SHOOT

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JUN-1973 Gere, W. U.S. Geological Survey
Updater 01-JUL-1978 Fraticelli, L. A. (Albers, J.) U.S. Geological Survey

Beyond USGS

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

External references

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.