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
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.
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.
California Gold
"Where to Find Gold in California" looks at the density of modern placer mining claims along with historical gold mining locations and mining district descriptions to determine areas of high gold discovery potential in California. Read more: Where to Find Gold in California.
