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Trinidad Mine

Past Producer in San Luis Obispo county in California, United States with commodity Chromium
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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. Nearby scientific data
  8. Economic information about the deposit and operations
  9. Land status
  10. Ownership information
  11. Production statistics
  12. Workings at the site
  13. Links to other databases
  14. Bibliographic references
  15. General comments
  16. Reporter information

Geologic information

Identification information

Deposit ID 10184459
MRDS ID W025018
MAS/MILS ID 0060790029
Record type Site
Current site name Trinidad Mine
Alternate or previous names La Trinidad
Related records 10111017

Geographic coordinates

Point of reference Main Entrance
Geographic coordinates: -120.68657, 35.36307 (WGS84)
Elevation 488
Location accuracy 100(meters)

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 029 S 012 E 33 SENE California

Commodities

Commodity Importance
Chromium Critical Primary

Nearby scientific data

Main Entrance (1) -120.68657, 35.36307
ListMap

Economic information

Economic information about the deposit and operations

Operation type Underground
Development status Past Producer
Commodity type Metallic
Significant No
Discovery year 1880
Year of first production 1880

Land status

Ownership category Military Reservation

Ownership information

  • Type Owner
    Owner Camp San Luis Obispo Military Res. Cal. National Guard
    Interest 100
    Home office California
    Year 1987

Production statistics

  • Year 1880
    Description Lump Ore Mined In 1880'S. 1400 Mt
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Chromium Chromium 1400mt
  • Year 1917
    Description Lump Ore Mined From 1917-1918 800 Mt
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Chromium Chromium 800mt
  • Year 1943
    Description Concentrates Produced From 1943-1944 850 Mt @ 45% With 3:1 Cr:Fe
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Conc. Chromium Chromium 850mt 45wt-pct
  • Year 1943
    Description Ore Mined From 1943-1944 4200 Mt
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Chromium Chromium 4200mt
  • Year 1943
    Description Lump Ore Mined From 1943-1944 50 Mt
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Chromium Chromium 50mt
  • Year 1954
    Description Concentrates Produced From 1954-1958 9000 Mt @ 47.5% - 2.7:1 Cr:Fe
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Conc. Chromium Chromium 9000mt 48wt-pct
  • Year 1954
    Description Ore Mined From 1954-1958 26200 Mt @ 16%
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Ore Chromium Chromium 26200mt 16wt-pct
  • Year 1954
    Description Lump Ore Mined From 1954-1958 2600 Mt @ 46% - 2.7:1 Cr:Fe
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Major Chromium Chromium 2600mt 46wt-pct

Comments on the reserve resource information

  • MAT 1 COL 1 TOTAL RESOURCES (C1+C2+C3+C4) MAT 1 COL 2 UPPER ORE BODY MAT 1 COL 3 LOWER ORE BODY MAT 1 COL 4 EAST POD MAT 1 COL 5 WEST POD MATRIX 2 COLUMN 1 REPRESENT 1990 ORE PRODUCTION MATRIX 2 COLUMN 2 REPRESENTS 1990 ORE PRODUCTION FROM TRINIDAD MINE AND INCLUDES DILUTION. MATRIX 2 COLUMN 3 REPRESENTS 1990 ORE PRODUCTION FROM LA PRIMERA MINE AND INCLUDES DILUTION MATRIX 3 COLUMN 1 REPRESENTS 1991 ORE PRODUCTION. ALL PRODUCTION IS FROM THE LA PRIMERA AND INCLUDES DILUTION. MATRIX 4 COLUMN 1 REPRESENTS 1992 ORE PRODUCTION. MATRIX 4 COLUMN 2 REPRESENTS 1992 ORE PRODUCTION FROM LA PRIMERA AND INCLUDES DILUTION. MATRIX 4 COLUMN 3 REPRESENTS 1992 ORE PRODUCTION FROM THE CASTRO MINE AND INCLUDES DILUTION. MATRIX 5 COLUMN 1 REPRESENTS 1993 ORE PRODUCTION. MATRIX 5 COLUMN 2 REPRESENTS 1993 ORE PRODUCTION FROM THE CASTRO MINE AND INCLUDES DILUTION. MATRIX 5 COLUMN 3 REPRESENTS 1993 ORE PRODUCTION FROM THE EUCALYPTUS MINE AND INCLUDES DILUTION. MATRIX 6 COLUMN 1 REPRESENTS 1994 ORE PRODUCTION. MATRIX 6 COLUMN 2 REPRESENTS 1994 ORE PRODUCTION FROM THE EUCALYPTUS MINE AND INCLUDES DILUTION. MATRIX 6 COLUMN 3 REPRESENTS 1994 ORE PRODUCTION FROM THE NORCROSS MINE AND INCLUDES DILUTION. MATRIX 7 COLUMN 1 REPRESENTS 1995-2000 ORE PRODUCTION AT 52,000 TPY. ALL PRODUCTION IS FROM THE NORCROSS MINE AND INCLUDES DILUTION. MATRIX 8 COLUMN 1 REPRESENTS 2001 ORE PRODUCTION. MATRIX 8 COLUMN 2 REPRESENTS 2001 ORE PRODUCTION FROM THE NORCROSS MINE AND INCLUDES DILUTION. MATRIX 8 COLUMN 3 REPRESENTS 2001 ORE PRODUCTION FROM THE SWEETWATER MINE AND INCLUDES DILUTION. MATRIX 9 COLUMN 1 REPRESENTS 2002 ORE PRODUCTION AND INCLUDES DILUTION. ALL 2002 PRODUCTION IS FROM THE SWEETWATER MINE.

Workings at the site

  • Type of workings Surface
    Area 20HA
    Field Value
    MAS Development Schedule # 1
    Mining Record # 1
    Status of Mining Method PROPOSED
    Mining Method STRIP-HILLSIDE
    Swell Factor .65
    Percent Waste Rock 77.4
    Avg. Overburden Thickness 30
    Primary Material Cover SAND, GRAVEL
    Percentage 0
    Secondary Material Cover M-HARD ROCKS
    Percentage 0
    Hardness of Ore M-HARD ROCKS
    Avg. Bench Height (meters) 0
    Max. Pit Slope (degrees) 45
    Capacity 200
    Capacity Units MT ORE/DAY
    Preprod. Stripping Vol. 240
    Unit Production Cost 4.1
    Units of Production $/MT ORE
    Operating Days per Year 260
    Operating Shifts per Day 1
    Year of Information 1987
  • Type of workings Surface
    Area 20HA
    Field Value
    MAS Development Schedule # 1
    Mining Record # 2
    Status of Mining Method PROPOSED
    Mining Method STRIP-HILLSIDE
    Swell Factor .65
    Percent Waste Rock 77.4
    Avg. Overburden Thickness 30
    Primary Material Cover SAND, GRAVEL
    Percentage 0
    Secondary Material Cover M-HARD ROCKS
    Percentage 0
    Hardness of Ore M-HARD ROCKS
    Avg. Bench Height (meters) 0
    Max. Pit Slope (degrees) 45
    Capacity 200
    Capacity Units MT ORE/DAY
    Preprod. Stripping Vol. 0
    Unit Production Cost 5.83
    Units of Production $/MT ORE
    Operating Days per Year 260
    Operating Shifts per Day 1
    Year of Information 1987
  • Type of workings Surface
    Area 20HA
    Field Value
    MAS Development Schedule # 1
    Mining Record # 3
    Status of Mining Method PROPOSED
    Mining Method STRIP-HILLSIDE
    Swell Factor .65
    Percent Waste Rock 77.4
    Avg. Overburden Thickness 30
    Primary Material Cover SAND, GRAVEL
    Percentage 0
    Secondary Material Cover M-HARD ROCKS
    Percentage 0
    Hardness of Ore M-HARD ROCKS
    Avg. Bench Height (meters) 0
    Max. Pit Slope (degrees) 45
    Capacity 200
    Capacity Units MT ORE/DAY
    Preprod. Stripping Vol. 0
    Unit Production Cost 5.83
    Units of Production $/MT ORE
    Operating Days per Year 260
    Operating Shifts per Day 1
    Year of Information 1987
  • Type of workings Surface
    Area 20HA
    Field Value
    MAS Development Schedule # 1
    Mining Record # 4
    Mining Method STRIP-HILLSIDE
    Swell Factor .65
    Percent Waste Rock 77.4
    Avg. Overburden Thickness 30
    Primary Material Cover SAND, GRAVEL
    Percentage 0
    Hardness of Ore SAND, GRAVEL
    Avg. Bench Height (meters) 0
    Max. Pit Slope (degrees) 45
    Capacity 200
    Preprod. Stripping Vol. 0
    Unit Production Cost 5.83
    Units of Production $/MT ORE
    Operating Days per Year 260
    Operating Shifts per Day 1
    Year of Information 1987
  • Type of workings Surface
    Area 20HA
    Field Value
    MAS Development Schedule # 1
    Mining Record # 5
    Status of Mining Method PROPOSED
    Mining Method STRIP-HILLSIDE
    Swell Factor .65
    Percent Waste Rock 77.4
    Avg. Overburden Thickness 30
    Primary Material Cover SAND, GRAVEL
    Percentage 0
    Secondary Material Cover M-HARD ROCKS
    Percentage 0
    Hardness of Ore M-HARD ROCKS
    Avg. Bench Height (meters) 0
    Max. Pit Slope (degrees) 45
    Capacity 200
    Capacity Units MT ORE/DAY
    Preprod. Stripping Vol. 0
    Unit Production Cost 5.83
    Units of Production $/MT ORE
    Operating Days per Year 260
    Operating Shifts per Day 1
    Year of Information 1987
  • Type of workings Surface
    Area 20HA
    Field Value
    MAS Development Schedule # 1
    Mining Record # 6
    Mining Method STRIP-HILLSIDE
    Swell Factor .65
    Percent Waste Rock 77.4
    Avg. Overburden Thickness 30
    Primary Material Cover SAND, GRAVEL
    Percentage 0
    Hardness of Ore SAND, GRAVEL
    Avg. Bench Height (meters) 0
    Max. Pit Slope (degrees) 45
    Capacity 200
    Preprod. Stripping Vol. 0
    Unit Production Cost 5.83
    Units of Production $/MT ORE
    Operating Days per Year 260
    Operating Shifts per Day 1
    Year of Information 1987
  • Type of workings Surface
    Area 20HA
    Field Value
    MAS Development Schedule # 1
    Mining Record # 7
    Status of Mining Method PROPOSED
    Mining Method STRIP-HILLSIDE
    Swell Factor .65
    Percent Waste Rock 77.4
    Avg. Overburden Thickness 30
    Primary Material Cover SAND, GRAVEL
    Percentage 0
    Secondary Material Cover M-HARD ROCKS
    Percentage 0
    Hardness of Ore M-HARD ROCKS
    Avg. Bench Height (meters) 0
    Max. Pit Slope (degrees) 45
    Capacity 200
    Capacity Units MT ORE/DAY
    Preprod. Stripping Vol. 0
    Unit Production Cost 2.37
    Units of Production $/MT ORE
    Operating Days per Year 260
    Operating Shifts per Day 1
    Year of Information 1987
  • Type of workings Surface
    Area 20HA
    Field Value
    MAS Development Schedule # 1
    Mining Record # 8
    Mining Method STRIP-HILLSIDE
    Swell Factor .65
    Percent Waste Rock 77.4
    Avg. Overburden Thickness 30
    Primary Material Cover SAND, GRAVEL
    Percentage 0
    Hardness of Ore SAND, GRAVEL
    Avg. Bench Height (meters) 0
    Max. Pit Slope (degrees) 45
    Capacity 200
    Preprod. Stripping Vol. 0
    Unit Production Cost 2.37
    Units of Production $/MT ORE
    Operating Days per Year 260
    Operating Shifts per Day 1
    Year of Information 1987

Reference information

Bibliographic references

  • Deposit

    CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD, CENTRAL

  • Deposit

    COAST REGION. SURFACE WATER DEGRADATION BY INACTIVE

  • Deposit

    METAL MINES IN NORTHWEST SAN LUIS OBISPO COUNTY, CA,

  • Deposit

    DECEMBER 1993 (P. 6-8).

  • Deposit

    CALIF. STATE MINING BUR. BULLETIN 76, 1918, P. 171.

  • Deposit

    CALIF. JOUR. MINES AND GEOL. V. 37, 1941, P. 163.

  • Deposit

    U.S. BUREAU OF MINES RI 4783, 1951, P. 5-6.

  • Deposit

    CALIF. DIV. MINES BULLETIN 134, 1953, PART II, CHAPT. 2,

  • Deposit

    P. 63-64.

General comments

Subject category Comment text
Environmental Factors CHROMITE DEPOSITS IN THE CHORRO CREEK WATERSHED ARE NOT SULFIDES WITH POTENTIAL TO GENERATE ACID MINE DRAINAGE THOUGH THEY MAY ERODE CHROMIUM, ALUMINUM, MAGNESIUM, IRON, MANGANESE, TITANIUM, CALCIUM, SILICON, AND NICKEL TO THE WATERSHED. METALS WHICH APPEAR TO BE ERODING FROM INACTIVE MINES INCLUDE MAGNESIUM, IRON, NICKEL, AND CHROMIUM. SAN LUISITO CREEK, PENNINGTON CREEK, AND UPPER CHORRO CREEK APPEAR TO BE THE MOST HEAVILY MINE-IMPACTED TRIBUTARIES IN THE CHORRO CREEK WATERSHED.

Reporter information

Type Date Name Affiliation Comment
Reporter 05-DEC-1994 Wetzel, Nicholas U.S. Bureau of Mines

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.