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Keystone-Union

Producer in Calaveras county in California, United States with commodities Copper, Silver, Gold
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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. Mineral occurrence model information
  10. Host and associated rocks
  11. Nearby scientific data
  12. Geologic structures
  13. Ore body information
  14. Controls for ore emplacement
  15. Economic information about the deposit and operations
  16. Mining district
  17. Production statistics
  18. Workings at the site
  19. Links to other databases
  20. Bibliographic references
  21. General comments
  22. Reporter information

Geologic information

Identification information

Deposit ID 10028813
MRDS ID M006028
Record type Site
Current site name Keystone-Union
Alternate or previous names Calaveras Copper
Related records 10235156

Geographic coordinates

Geographic coordinates: -120.64379, 37.9763 (WGS84)
Relative position IN THE TOWN OF COPPEROPOLIS; NE1/4 SW1/4 OF SEC. MAP GP-561. ELEV: 1000'

Site location context

Political divisions (FIPS codes)

Calaveras(county)

California(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Copperopolis(quadrangle 1:24,000 scale)

Oakdale(quadrangle 1:100,000 scale)

San Jose(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper Stanislaus(hydrologic unit)

San Joaquin(hydrologic accounting unit)

San Joaquin(hydrologic subregion)

California(hydrologic region)

Geographic areas

Country State County
United States California Calaveras

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 002N 012E 34 California

Commodities

Commodity Importance
Copper Primary
Silver Secondary
Gold Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrite Ore
Quartz Gangue

Alteration

  • (Local) Chloritization

Analytical data

Result TENOR
Result 1 - 18 % CU, MOST HIGHER THAN 2 %

Mineral occurrence model information

Model code 184
USGS model code 28a
Deposit model name Massive sulfide, kuroko
Mark3 model number 93

Host and associated rocks

  • Host or associated Associated
    Rock type Metamorphic Rock > Serpentinite
    Stratigraphic age (youngest) Late Jurassic
  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Slate
  • Host or associated Host
    Rock type Metamorphic Rock > Schist

Nearby scientific data

(1) -120.64379, 37.9763
ListMap

Economic information

Geologic structures

Type of structure Local
Structure description Fault; East Dipping On Eastern Boundary Of Serpentine Body. Appears Continuous With "Footwall Fault" Of North Keystone Mine. Talcose Gouge With Disseminated Magnetite. Displacement Decreases Southward, 100 Ft. Displacement, Quartz Diorite Intrusion Near Stockton Road.

Ore body information

  • General form LENTICULAR
    Thickness 10.06M
    Length 106.68M

Controls for ore emplacement

  • 1. Zone Of Chloritization, 2. Fault

Comments on the geologic information

  • GEOL.DESC: SIMILAR TO THE NORTH KEYSTONE MINE AREA, DARK BLUE-GRAY ARGILLACEOUS SLATE, GREEN SCHIST AND GREENSTONE, BEDDED TUFF, HORNSTONE AND VOLCANIC BRECCIA. MOST HAVE WELL DEVELOPED SCHISTOSITY OR CLEVAGE DIPPING STEEPLY EASTWARD. 200 FT. WEST IS LARGE GRANODIORITE INTRUSION, LENTICULAR, 2,000 FT. LONG, 240 FT. WIDE. SERPENTINE BODY 1,730 FT. LONG AND 85 FT. WIDE LIES EAST OF GRANODIORITE BODY.

Economic information about the deposit and operations

Development status Producer
Commodity type Metallic
Deposit size Large
Significant No
Production years 1861 - 1946

Mining district

District name Copperopolis Mines

Production statistics

  • Year 1861
    Period 1861 -
    Material ORE
    Accuracy Accurate
    Description Cp_Grade: ^317 Oz Au, 28,945 Oz Ag 62,600 ,131 Lbs Cu.
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Copper Copper 2795mt
    Ore Silver Silver 817300g
    Major Ore Gold Gold 8950g

Comments on the production information

  • MORE DETAIL PRODUCTION VALUES CAN BE OBTAINED IN HEYL, G.R., 1948 , P. 96 - 97 .

Workings at the site

  • Type of workings Underground
    Overall depth 411.48M

Comments on the workings information

  • 6 SHAFTS; NORTH TO SOUTH, 1)KEYSTONE-DISCOVERY, 2)KEYSTONE, 3)UNION NO. 1, 4)UNION NO. 2, 5)UNION NO. 3, 6)SOUTH UNION. DEVELOPED ALONG 2,000 FT. LENGTH OF MINERALIZED ZONE.

Reference information

Bibliographic references

  • Deposit

    HEYL, G.R., 1948 , ORE DEPOSITS OF COPPEROPOLIS, CALAVERAS COUNTY, CALIFORNIA; COPPER IN CALIFORNIA BULL. 144 ; DIV. OF MINES, P. 106 - 108 , P. 96 - 97 .

  • Deposit

    EC. MINERAL MAP NO. 6

  • Production

    HEYL, G.R., 1948 , P. 96 - 97 (SEE REF.)

General comments

Subject category Comment text
Deposit ORE BODIES LIE PARALLEL TO FOLIATION, STEEP NORTH RAKE, PITCH LENGTH 600 FT OR 1200 FT.
Deposit ADD. REF.NO.4. CALIF. B. 145, PL. 2; V. 53, NOS. 3 & 4, P. 427; EC. MIN. MAP NO. 7, 1957; COUNTY REPT. NO. 2, P. 24-27, 131 AND PL. D; USGS MR-34; MANUAL OF WAR MINERALS OF COUNTIES OF NORTHERN CALIFORNIA, 2ND ED., SEPT. 1, 1944, P. 26; CALIF. B. 176, P. 170, 171, 174

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JUN-1972 Gere, W. U.S. Geological Survey
Updater 01-JUN-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.

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.