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Central Eureka

Producer in Amador county in California, United States with commodities Gold, Silver, Iron, Zinc, Lead, Copper
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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. Land status
  15. Ownership information
  16. Links to other databases
  17. Bibliographic references
  18. General comments
  19. Reporter information

Geologic information

Identification information

Deposit ID 10028222
MRDS ID M005088
Record type Site
Current site name Central Eureka
Related records 10187647

Geographic coordinates

Geographic coordinates: -120.79796, 38.38296 (WGS84)
Relative position AT THE TOWN OF SUTTER CREEK

Site location context

Political divisions (FIPS codes)

Amador(county)

California(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Amador City(quadrangle 1:24,000 scale)

San Andreas(quadrangle 1:100,000 scale)

Sacramento(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper Mokelumne(hydrologic unit)

San Joaquin(hydrologic accounting unit)

San Joaquin(hydrologic subregion)

California(hydrologic region)

Geographic areas

Country State County
United States California Amador

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 006 011E 08 California

Comments on the location information

  • SW 1/4

Commodities

Commodity Importance
Gold Primary
Silver Primary
Iron Tertiary
Zinc Critical Tertiary
Lead Tertiary
Copper Tertiary

Comments on the commodity information

  • GOLD ALLOYED WITH SILVER IN FREE-MILLING STATE OR GOLD DISSEMINATED WITH PYRITE; PYRITE AND ARSENOPYRITE COMMON, SPHALERITE, CHALCOPYRITE AND GALENA MINOR.

Materials information

Materials Type of material
Chalcopyrite Ore
Galena Ore
Gold Ore
Pyrite Ore
Silver Ore
Sphalerite Ore
Albite Gangue
Ankerite Gangue
Quartz Gangue

Alteration

  • (Local) Hydrothermal Alteration Of Meta-Andesite Causing Blocky Meta-Andesite To Mix With Quartz In Ore Veins; Meta-Andesite Altered To Schist In Places.

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Slate
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite

Nearby scientific data

(1) -120.79796, 38.38296
ListMap

Economic information

Ore body information

  • General form TABULAR/PINCH AND SWELL
    Strike N 40 W
    Dip 71 NE
    Thickness 6.1M
    Depth to top 0M

Controls for ore emplacement

  • Shear Zone

Comments on the geologic information

  • GEOL.DESC: ORE BODIES CONSIST OF QUARTZ-ANKERITE-ALBITE AND MASSIVE QUARTZ STRINGERS, LENSES AND VEINS. IN UPPER PORTION OF MINE ORE BODIES IN BLACK SLATE AT CONTACT WITH META-ANDESITE; META-ANDESITE HANGING WALL BUT BOTH IT AND SLATE FOUND ON BOTH WALLS DUE TO VEINS CROSSING INTERBEDDED LENSES OF BOTH ROCK TYPES. ORE VEIN AT DEPTH IS A BLACK GOUGE WITH QUARTZ STRINGERS. AVERAGE THICKNESS OF MINERALIZED BLACK GOUGE ZONE 8 FT. ONE ORE BODY PARALLEL TO ORE VEIN 420 FT. LONG, 280 FT. WIDE; LARGE WEDGE 850 FT. LONG, 35 FT. WIDE AND AS GREAT AS 125 FT. CONTAINS SEVERAL ORE LENSES.

Economic information about the deposit and operations

Development status Producer
Commodity type Metallic
Deposit size Large
Significant No
Discovery year 1855

Land status

Ownership category Private

Ownership information

  • Type Operator
    Owner Central Eureka Mining Co.

Comments on the production information

  • CENTRAL EUREKA , ORIGINALLY "SUMMIT" WORKED FROM 1855-1875; REOPENED IN 1895 AS CENTRAL EUREKA; OPERATED INTERMITTENTLY UNTIL 1924 WHEN CONSOLIDATED WITH OLD EUREKA WHICH HAD BEEN WORKED INTERMITTENTLY SINCE 1852. WORKED INTERMITTENTLY FROM 1930 TO 1942; MINING RESUMED IN 1946 BUT LITTLE DONE UNTIL 1948. PRODUCED 39,440 TONS OF ORE YIELDING MORE THAN $500,000 IN GOLD AND SILVER IN 1951. TOTAL PRODUCTION (BOTH MINES) $36,000,000 APPROX. TO END OF 1951. GOLD ALLOYED WITH SILVER IN FREE-MILLING STATE OR DISSEMINATED IN PYRITE, PYRITE AND ARSENOPYRITE ARE COMMON, SPHALERITE, CHALCOPYRITE, AND GALENA ARE PRESENT IN MINOR AMOUNTS

Comments on the workings information

  • 2 INCLINED SHAFTS AVERAGING 65 DEGREES 4855 AND 3500 FT.; 3500 FT. SHAFT WITH WINZE AT BASE TO 4150 FT., WATER CONFINED TO THIS SHAFT; LEVELS AT 2900 , 3100 , 3400 , 3500 , 3600 , 3700 , 3800 , 3900 , 4150 , FT. WITH TOTAL OF SEVERAL THOUSAND FT. OF DRIFTS; DUE TO CONSIDERABLE GOUGE ON WALLS OF MOST LEVELS, STOPES TIMBERED CLOSE TO FACE; CUT AND FILL METHOD OF STOPING USED.

Reference information

Bibliographic references

  • Deposit

    CARLSON, D.W. AND CLARK, W.B., 1954 , MINES AND MIN. RES. OF AMADOR COUNTY, CAL.: CJMG VOL. 50 , P. 173

  • Deposit

    LOGAN, C.A., 1934 , MOTHER LODE GOLD BELT OF CAL.: CBM BULL. 108 , P. 74 - 80 .

  • Deposit

    USGS PROF. PAPER 157, P. 59-62

  • Production

    CARLSON, D.W. AND CLARK, W.B., 1954

General comments

Subject category Comment text
Deposit OLD EUREKA MINE INCORPERATED WITH CENTRAL EUREKA MINE; BOTH OPERATED SEPARATELY UNTIL 1924 WHEN THEY MERGED.
Deposit Discovery Year: 1850'S

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JUN-1972 Gere, W. U.S. Geological Survey
Updater 01-APR-1978 Tatkin, T.; 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.