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Pioneer - Lilyama

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

Geologic information

Identification information

Deposit ID 10029708
MRDS ID M007430
Record type Site
Current site name Pioneer - Lilyama
Alternate or previous names Little Emma, Volo

Geographic coordinates

Geographic coordinates: -120.96825, 38.83517 (WGS84)
Relative position W1/2 SW1/4. NR. W1/4 COR. (LILYAMA)

Site location context

Political divisions (FIPS codes)

El Dorado(county)

California(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Coloma(quadrangle 1:24,000 scale)

Placerville(quadrangle 1:100,000 scale)

Sacramento(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

South Fork American(hydrologic unit)

Lower Sacramento(hydrologic accounting unit)

Sacramento(hydrologic subregion)

California(hydrologic region)

Geographic areas

Country State County
United States California El Dorado

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 011N 009E 03 California

Commodities

Commodity Importance
Copper Primary
Gold Secondary
Silver Secondary
Iron Tertiary
Tungsten Critical Tertiary

Materials information

Materials Type of material
Chalcopyrite Ore
Idocrase Ore
Pyrite Ore
Epidote Gangue
Garnet Gangue
Magnetite Gangue
Quartz Gangue

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite
  • Host or associated Host
    Rock type Metamorphic Rock > Hornfels

Economic information

Geologic structures

Type of structure Local
Structure description Faults, Joints: Lilyama Area, Member Faults Trend Approximately East And Dip 42 - 65 South, With Apparent Displacements Of Less Than 5 Ft.

Ore body information

  • General form PODS
    Width 30.48M

Controls for ore emplacement

  • Faults, Joints

Comments on the geologic information

  • GEOL.DESC: MOST WIDESPREAD ROCK IN THE STOCK IS A MED. TO COARSE GRAINED HORNBLENDE GRANODIORITE. A LIGHTER COLORED FACIES OF GRANODIORITE, NEARLY DEVOID OF MAFIC MINERALS UNDERLIES A LARGE AREA SE OF THE MINES. SYENITE PORPHYRY IS PRESENT AS A NARROW DIKE INTRUDING HORNFELS IN LOWER TUNNEL OF LILYAMA MINE. THE ADIT ALSO EXPOSES AN IRREGULAR DIKE OF DARK HORNBLENDE DIORITE WHICH IS PENETRATED BY STRINGERS OF GRANODIORITE. THE MOST PREVALENT METAMORPHIC ROCK IS THE FINE - GRAINED HORNFELS - LIGHT GRAYGREEN TO BLACK IN COLOR AND LOCALLY CONTAINING LARGE BIOTITE FLAKES. A GARNET QUARTZITE WITH A FINE - GRAINED SACCHAROIDAL TEXTURE CROPS OUT DIRECTLY ABOVE LILYAMA MINE WORKINGS. AT THE PIONEER MINE, A COARSELY CRYSTALLINE WHITE MARBLE IS THE IMPORTANT ROCK TYPE, IT TRENDS SLIGHTLY WEST OF NORTH, DIPS NEARLY VERTICAL AND IS NOT CONTINUOUS.

Economic information about the deposit and operations

Development status Producer
Commodity type Metallic
Deposit size Medium
Significant No
Production years 1944 - 1946

Ownership information

  • Type Operator
    Owner Wilcox - Lilyama Mining Co. (F.R. Wicks, Mgr.)

Production statistics

  • Year 1946
    Period - 1946
    Material ORE
    Accuracy Accurate
    Description Cp_Grade: ^Avg. 2.5 % Cu.
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Ore Copper Copper 3wt-pct

Comments on the production information

  • 1860'S WORKED AS 2 SEPERATE MINES, MAIN COPPER DEPOSIT DISCOVERED 1889 - 1890. 1955 REHABILITATED THE MINE, SOME ORE HAS BEEN PRODUCED AND STOCKPILED AWAITING COMPLETION OF WORK ON MILL. PRODUCTION TABLE FIGURES ARE FROM THE LILYAMA MINE.

Workings at the site

  • Type of workings Underground
    Overall depth 40.23M

Comments on the workings information

  • LILYAMA MINE: 4 ADITS TOTAL LENGTH GREATER THAN 1,000 FT., DEVELOPED THROUGH VERTICAL RANGE OF 132 FT., NOT CONNECTED UNDERGROUND. PIONEER MINE: 4 SHAFTS AND AN ADIT, OF THESE ONLY ONE 80 FT. SHAFT AND A SHORT CROSSCUT WERE ACCESSIBLE.

Reference information

Bibliographic references

  • Deposit

    CLARK, W. B. AND CARLSON, D. W., 1956 : MINES AND MINERAL RESOURCES, EL DORADO COUNTY, CA.: CALIF. JOUR. MINES AND GEOLOGY, VOL. 52 , NO. 4 : DIV. OF MINES, P. 397 - 398 , 482 .

  • Deposit

    COX, M. W., ETAL, 1948 : GEOLOGY OF THE LILYAMA AND PIONEER MINES, EL DORADO COUNTY, CA.: COPPER IN CALIFORNIA BULL. 144 : DIV. OF MINES, P. 43 - 47 .

  • Deposit

    IN 1957, PRODUCED ALL OF THE COUNTY'S RECOVERABLE COPPER AND APPRECIABLE AMOUNTS OF GOLD AND SILVER -- U.S. BUREAU OF MINES MIN. YEARBOOK 1957, V. 3, P. 216

  • Production

    COX, M. W., ETAL, 1948 , P. 44

General comments

Subject category Comment text
Deposit TACTITE PODS WHICH RANGE IN SIZE FROM SMALL PODS TO THOSE 100 OR MORE FT. IN WIDTH. THE SULFIDES OCCUR AS IRREGULAR MASSES OR VEINLETS AND ARE ASSOCIATED WITH ABUNDANT EUHEDRAL MAGNETITE CRYSTALS.
Deposit THE ORE BODIES ARE THOSE PARTS OF THE TACTITE THAT CONTAIN COMMERCIAL AMOUNTS OF CHALCOPYRITE AND BORNITE. THE PIONEER MINE IS ABOUT 2,000 FT. FROM THE LILYAMA. V. 34, NO. 3, PL. II SHOWS THE PIONEER AS AN UNPATENTED CLAIM OF 20.65 ACRES.

Reporter information

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