Castro Mine

The Castro Mine is a chromium mine located in San Luis Obispo county, California at an elevation of 1,601 feet.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

Name: Castro Mine  

State:  California

County:  San Luis Obispo

Elevation: 1,601 Feet (488 Meters)

Commodity: Chromium

Lat, Long: 35.3736, -120.70750

Map: View on Google Maps

Satelite View

MRDS mine locations are often very general, and in some cases are incorrect. Some mine remains have been covered or removed by modern industrial activity or by development of things like housing. The satellite view offers a quick glimpse as to whether the MRDS location corresponds to visible mine remains.


Satelite image of the Castro Mine

Castro Mine MRDS details

Site Name

Primary: Castro Mine
Secondary: Castro Chrome Mine


Commodity

Primary: Chromium


Location

State: California
County: San Luis Obispo
District: Questa Pass


Land Status

Land ownership: Private
Note: the land ownership field only identifies whether the area the mine is in is generally on public lands like Forest Service or BLM land, or if it is in an area that is generally private property. It does not definitively identify property status, nor does it indicate claim status or whether an area is open to prospecting. Always respect private property.


Holdings

Type: Patented


Workings

Not available


Ownership

Owner Name: Ernest Vallmer Jr.
Percent: 100.0
Home Office: California
Info Year: 1976

Owner Name: Castro Chrome Associates-Last Operators
Info Year: 1976
Years: 1953 - 1957


Production

Year: 1942
Description: Concentrates Produced From 1942-1944 2550 Mt @ 42 Pct-2.7:1 Cr:Fe
Year: 1933
Description: Concentrates Produced 80 Metric Tons
Year: 1917
Description: Concentrates Produced From 1917-1919 3150 Metric Tons @ 40 Pct
Year: 1953
Description: Concentrates Produced From 1953-1957 15100 Mt @ 42 Pct-2.4:1 Cr:Fe


Deposit

Record Type: Site
Operation Category: Past Producer
Operation Type: Surface
Mining Method: Unknown
Year First Production: 1918
Discovery Year: 1876
Years of Production:
Organization:
Significant: N


Physiography

General Physiographic Area: Pacific Mountain System
Physiographic Province: Pacific Border Province
Physiographic Section: California Coast Ranges


Mineral Deposit Model

Not available


Orebody

Not available


Structure

Not available


Alterations

Not available


Rocks

Not available


Analytical Data

Not available


Materials

Unknown: Chromite
Unknown: Magnesite
Unknown: Magnetite
Unknown: Serpentine
Unknown: Talc


Comments

Comment (Reserve-Resource): MAT 1 COL 1 REPRESENTS TOTAL HIGH AND LOW GRADE RESOURCES. MAT 1 COL 2 REPRESENTS HIGH GRADE ORE. MAT 1 COL 3 REPRESENTS LOW GRADE ORE.

Comment (Deposit): CALCULATED AVERAGE GRADE OF 15111 LONG TONS SHIPPED IN 1953-1 .65 % CR2O3, 12.24%FE,2.32 TO 1 CR/FE RATIO. TOTAL PRODUCTION ESTIMATED TO BE OVER 111,168 LONG TONS OF 2 3. LOW PROBABILTY OF DISCOVERING NEW RESERVES BECAUSE OF EXT PAST EXPLORATION. INSUFFICIENT DATA FOR MATRIX CALCULATIONS. ANALYSIS BY CDMG IN 1976 GAVE FOLLOWING PERCENTAGES-DISSEMIN E=SI02 08.00,CR2O3 45.31,FEO 08.82,TOTAL FE 12.87,AL203 13.2 7.83,CR/FE 3.10. FE 11.67,AL203 12.99,MGO 20.48,CR/FE 2.69.BANDED ORE=S102 21 03 29.23,FEO 9.39,TOTAL FE 12.07,AL203 11.81,MGO 23.14,CR/FE

Comment (Environmental Factors): CHROMITE DEPOSITS IN THE CHORRO CREEK WATERSHED ARE NOT SULFIDES WITH POTENTIAL TO GENERATE ACID MINE DRAINAGE THOUGH THEY MAY ERODE CHROMIUM, ALUMINU, MAGNESIUM, IRON, MANGANESE, TITANIUM, CALCIUM, SILICON, AND NICKEL TO THE WATERSHED. METALS WHICH APPEAR TO BE ERODING FROM INACTIVE MINES INCLUDE MANGESIUM, 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.


References

Reference (Deposit): CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD, CENTRAL

Reference (Deposit): COAST REGION. SURFACE WATER DEGRADATION BY INACTIVE

Reference (Deposit): METAL MINES IN NORTHWEST SAN LUIS OBISPO COUNTY, CA,

Reference (Deposit): DECEMBER 1993 (P. 6-8).

Reference (Deposit): CALIF. STATE MINING BUR. BULLETIN 76, 1918, P. 167-169.

Reference (Deposit): CALIF. FOUR. MINES AND GEOL V. 37, 1941, P. 141, 161.

Reference (Deposit): U.S. GEOLOGICAL SURVEY BULLETIN 945-B, 1944, P. 34-37.

Reference (Deposit): U.S. BUREAU OF MINES RI 4783, 1951, P. 4-5.

Reference (Deposit): CALIF. DIV. MINES BULLETIN 134, 1953, PART II, CHAPT. 2,

Reference (Deposit): P. 60-61.


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