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

La Primera

Past Producer in San Luis Obispo county in California, United States with commodity Chromium
Map
XML
JSON
KML
C
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. Economic information about the deposit and operations
  13. Land status
  14. Ownership information
  15. Workings at the site
  16. Links to other databases
  17. Bibliographic references
  18. General comments
  19. Reporter information

Geologic information

Identification information

Deposit ID 10103912
MRDS ID M100576
Record type Site
Current site name La Primera
Alternate or previous names Hardface Group 1950's
Related records 10286703

Geographic coordinates

Geographic coordinates: -120.68764, 35.35858 (WGS84)
Elevation 411
Relative position APPROX. 9 KM NNW OF SAN LUIS OBISPO, CA.

Site location context

Political divisions (FIPS codes)

San Luis Obispo(county)

California(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

San Luis Obispo(quadrangle 1:24,000 scale)

San Luis Obispo(quadrangle 1:100,000 scale)

San Luis Obispo(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Central Coastal(hydrologic unit)

Central California Coastal(hydrologic accounting unit)

Central California Coastal(hydrologic subregion)

California(hydrologic region)

Federal lands

ST(Federal land areas administered by ST)

Geographic areas

Country State County
United States California San Luis Obispo

Public Land Survey System information

Meridian Township Range Section Fraction State
Mount Diablo 029S;029S;029S 012E;012E;012E 33;33;33 SW; NE; SE California

Comments on the location information

  • MINE LOCATED ON SMALL SPUR HEADING SOUTH OFF THE SANTA LUCIA RANGE. ; INFO FROM LAND.ST :(1975)

Commodities

Commodity Importance
Chromium Critical Primary

Comments on the commodity information

  • LUMP ORE (1950'S) AVERAGED 44.6% CR2O3, 11% FE, CR TO FE RATIO 2.6

Materials information

Materials Type of material
Chromite Ore

Analytical data

Result CONCENTRATES (1950'S) AVERAGED 45.8% CR2O3, 13.2% FE, CR TO FE RATIO 2.3.

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Ultramafic Intrusive Rock
  • Host or associated Host
    Rock type Plutonic Rock > Ultramafic Intrusive Rock > Peridotite > Dunite
    Rock unit name Franciscan;Knoxville
    Rock description Franciscan;Knoxville

Nearby scientific data

(1) -120.68764, 35.35858
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description Volc. And Sed. Rocks Folded Into Syncline

Ore body information

  • General form LENSE
    Strike N 37 E
    Dip 10 N
  • General form LENSE
    Dip 10 N

Comments on the geologic information

  • ULTRAMAFIC AND DIABASE INTRUSIVE BODIES USUALLY 4-5 KM LONG AND 1 KM THICK, ARE ELONGATE, AND NW-SE TRENDING. ULTRAMAFIC BODY CONTAINING MOST OF CHROMITE EXPOSED CONTINUOUSLY FOR 16 KM.

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant No
Discovery year 1885
Year of first production 1885
Year of last production 1958

Land status

Ownership category National Forest

Ownership information

  • Type Operator
    Owner Pierce Brothers, Morro Bay, Ca.
  • Type Owner
    Owner Mineral Rights Held By Arther E. Schwartz
    Home office C/O K. Pierce, Trinidad Mining Co., Inc., 434 Monterey St, Morro Bay, Ca. 93442

Workings at the site

  • Type of workings Surface
    Overall depth 6M
    Overall length 45.72M
    Overall width 30M

Comments on the workings information

  • WORKINGS SEEN IN 1975 CONSISTED OF A LARGE PIT AND EXISTANCE DUMPS.

Reference information

Bibliographic references

  • Deposit

    STINSON, M.C., 1975, CDMG MINERAL PROPERTY REPORT, UNPUBLISHED

  • Production

    CDMG MINERAL PROP. REPORT, UNPUBLISHED.

General comments

Subject category Comment text
Deposit A 0.2 M THICK LAYER OF MASSIVE CHROMITE EXPOSED IN PIT FLOOR AND WALLS.
Deposit Discovery Year: 1880'S

Reporter information

Type Date Name Affiliation Comment
Reporter 01-MAR-1982 Oster, Karel L. (Albers, John P.) 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.