1. Mineral Resources
  2. Online Spatial Data
  3. Mineral Resource Data System (MRDS)

Duncan

Past Producer in Mariposa county in California, United States with commodities Gold, Silver
Map
XML
JSON
KML
B
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. Host and associated rocks
  9. Nearby scientific data
  10. Ore body information
  11. Economic information about the deposit and operations
  12. Ownership information
  13. Production statistics
  14. Workings at the site
  15. Links to other databases
  16. Bibliographic references
  17. General comments
  18. Reporter information

Geologic information

Identification information

Deposit ID 10030938
MRDS ID M009441
Record type Site
Current site name Duncan
Alternate or previous names Lost Douglas
Related records 10163739

Geographic coordinates

Geographic coordinates: -120.21682, 37.49076 (WGS84)
Elevation 282
Relative position 7 1/2 MI. NW OF CATHEY'S VALLEY

Site location context

Political divisions (FIPS codes)

Mariposa(county)

California(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Indian Gulch(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 005S 016E 16,21 California

Comments on the location information

  • SHORT DISTANCE W OF COMMON 1/4 COR. ON MT. BULLIAN R

Commodities

Commodity Importance
Gold Primary
Silver Secondary

Comments on the commodity information

  • LAST ORE MILLED WAS OF MARGINAL GRADE.

Materials information

Materials Type of material
Gold Ore
Pyrite Ore
Silver Ore

Host and associated rocks

  • Host or associated Host
    Rock type Metamorphic Rock > Hornfels
    Stratigraphic age (youngest) Late Jurassic
  • Host or associated Host
    Rock type Metamorphic Rock > Metavolcanic Rock > Mafic Metamorphic Rock > Greenstone
  • Host or associated Host
    Rock type Metamorphic Rock > Schist

Nearby scientific data

(1) -120.21682, 37.49076
ListMap

Economic information

Ore body information

  • General form PINCH & SWELL
    Strike N 50 W
    Dip 45 NE
    Thickness 1.52M

Comments on the geologic information

  • GEOL.DESC: VEIN MEASURED AT SURFACE, 2 - 5 FT. ACROSS. WALL ROCKS ARE SCHISTOSE GREENSTONE, QUARTZ BIOTITE SCHIST AND QUARTZ BIOTITE HORNFELS.

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant No
Discovery year 1870
Production years 1897 - 1898 , 1927 , 1932 - 1935

Ownership information

  • Type Operator
    Owner George D. Turner

Production statistics

  • Year 1927
    Material AU
    Accuracy Accurate
    Description Ap_Grade: ^ .14 Oz/Ton Ag
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Silver Silver 4g/mt
  • Year 1927
    Material ORE
    Accuracy Accurate
    Description Ap_Grade: ^.45 Oz/Ton Au
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Ore Gold Gold 13g/mt
  • Year 1935
    Period - 1935
    Material ORE
    Accuracy Accurate
    Description Cp_Grade: ^.08 Oz/Ton Au .04 Oz/Ton Ag
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Silver Silver 1g/mt
    Major Ore Gold Gold 2g/mt

Comments on the production information

  • PRODUCTION RECORDS INCOMPLETE. IN 1897- 98, 246 OZ. OF GOLD RECOVERED FROM UNKNOWN QUANTITY OF ORE; IN 1927, 500 TONS OF ORE YIELDED 219.82 OZ. GOLD AND 70 OZ. SILVER. FROM 1932-1935, 1146 TONS OF ORE YIELDED 90 OZ. GOLD AND 45 OZ. SILVER. IDLE SINCE LATE 1930'S AND NO EQUIPMENT ON PROPERTY.

Workings at the site

  • Type of workings Surface/Underground
    Area 17.807HA
    Overall length 777.24M

Comments on the workings information

  • SERIES OF OPEN PITS AND CAVED SHAFTS STRUNG OUT ALONG THE VEIN FOR NEARLY 1/2 MILE. MAIN SHAFT 325' IN 1935.

Reference information

Bibliographic references

  • Deposit

    BOWEN, O. E., JR., & GRAY, H., JR., 1957 , MINES AND MINERAL DEPOSITS OF MARIPOSA COUNTY, CALIF.: CALIF. JOUR. MINES & GEOL., VOL. 53 , NOS. 1 & 2 , P. 96 , 256 .

  • Deposit

    LAIZURE, C. MCK., 1928 , S. F. FIELD DIV. - MARIPOSA COUNTY: 24TH REPORT STATE MINERALOGIST, VOL. 24 , NO. 2 , P. 85 .

  • Production

    BOWEN AND GRAY, 1957

General comments

Subject category Comment text
Deposit VEIN, POCKETS, ORE SHOOTS
Deposit ONE PATENTED CLAIM. MINE IS NOTED FOR ITS POCKETY CHARACTER.

Reporter information

Type Date Name Affiliation Comment
Reporter 01-JUN-1973 Gere, W. U.S. Geological Survey
Updater 01-DEC-1978 Hayden, F. (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.