Graysill Mine

The Graysill Mine is a vanadium and uranium mine located in San Juan county, Colorado at an elevation of 10,879 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

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.

Site Name

Primary: Graysill Mine
Secondary: Graysill Group
Secondary: Claims: Graysill 1-9

Commodity

Primary: Vanadium
Primary: Uranium

Location

State: Colorado
County: San Juan
District: Hermosa Peak Area

Land Status

Land ownership: National Forest
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.
Administrative Organization: San Juan N. F.

Holdings

Not available

Workings

Not available

Ownership

Owner Name: Vanadium Corp. Of America
Home Office: Durango, Co.
Years: 1967 -

Production

Year: 1971
Time Period: 1950-1971
Description: Cp_Grade: ^2.41% V2o5, 0.08% V3o8 (Graysill No.2)
Year: 1971
Time Period: 1950-1971
Description: Cp_Grade: ^1.907% V2o5, 0.049% V3o8 (Graysill No. 1)

Deposit

Record Type: Site
Operation Category: Past Producer
Operation Type: Unknown
Year First Production: 1947
Discovery Year: 1945
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

General Physiographic Area: Rocky Mountain System
Physiographic Province: Southern Rocky Mountains

Mineral Deposit Model

Not available

Orebody

Not available

Structure

Type: R
Description: San Juan Uplift

Type: L
Description: Rico Dome, Unnamed Faults

Alterations

Not available

Rocks

Name: Rhyodacite
Role: Associated
Age Type: Host Rock Unit
Age Young: Late Jurassic

Name: Rhyodacite
Role: Associated
Age Type: Host Rock
Age Young: Late Jurassic

Name: Rhyodacite
Role: Associated
Age Type: Associated Rock
Age Young: Pliocene

Analytical Data

Not available

Materials

Ore: Roscoelite
Ore: Carnotite

Comments

Comment (Production): PARTIAL PRODUCTION RECORD. PRODUCTION PRIOR TO 1950 UNKNOWN; NO PRODUCTION IN 1954; NO CDM PRODUCTION FIGURES AFTER 1964; EXPLORATION AND DEVELOPMENT CITED BY CDM RECORDS FOR 1960-1963, 1965-1967.

Comment (Development): DEPOSIT DISCOVERED IN 1945 BY EXPLORATORY DRILLING. FOUR TUNNELS DEVELOPED BY 1947, AND FIVE ADDITIONAL TUNNELS BY 1949. DEPOSIT MINED BY ROOM-AND-PILLAR METHODS, WITH SOME TUNNELS EVENTUALLY CONNECTING THROUGH CROSSCUTS AND LARGER ROOMS. ORE FIRST SHIPPED TO VANADIUM COMPANY OF AMERICA'S REDUCTION PLANT IN NATURITA, BUT BY 1950S ORE WAS SHIPPED TO TO VCA'S DURANGO MILL, A SALT ROAST-CARBONATE LEACH-ACID LEACH EXTRACTION PLANT. EXPLORATION AND DEVELOPMENT, ASSESSMENT, AND REHAB DONE IN 1960-63 AND 1965-67.

Comment (Deposit): ROSCOELITE ORE AND POSSIBLY CARNOTITE ASSOCIATED WITH CARBON TRASH IN ESSENTIALLY FLAT-LYING ENTRADA SANDSTONE IN LAYER 2 TO 6 FT THICK. MINERALIZATION MAY HAVE BEEN INFLUENCED BY PROXIMITY OF SILLS AROUND HERMOSA MTN, SLIDEROCK RIDGE, AND WEST SIDE OF GRAYSILL MTN. FAULTS IN MINE AREA TREND N 20 AND 70 E.

Comment (Workings): SURFACE EXCAVATION; NINE TUNNELS FROM 75 TO 500 IN LENGTH, SOME INTERCONNECTED BY CROSSCUTS AND ROOMS AND PILLARS

Comment (Location): (LAND STATUS AND ADMINISTRATIVE AREA LOCATIONS CALCULATED USING GIS OVERLAY ANALYSIS FOR SAN JUAN N. F.). NW OF GRAYSILL MTN NEAR HEAD OF HERMOSA CREEK 0.4 MILE SOUTH OF BOLAM PASS. CLAIMS PROBABLY EXTEND INTO ADJACENT UNSURVEYED SECTIONS AND INTO DOLORES CO. ; INFO FROM LAND.ST :1975

References

Reference (Deposit): NELSON-MOORE, J.L., AND OTHERS, 1978, RADIOACTIVE MINERAL OCCURRENCES OF COLORADO AND BIBLIOGRAPHY: CGS BULL. 40, P. 398.

Reference (Deposit): CROSS, WHITMAN, AND HOLE, A.D., 1910, DESCRIPTION OF THE ENGINEER MOUNTAIN QUADRANGLE: USGS FOLIO 171.

Reference (Deposit): FINCH, W.I., 1967, GEOLOGY OF EPIGENETIC URANIUM DEPOSITS IN SANDSTONE IN THE UNITED STATES: USGS PROF. PAPER 538, P. 141.

Reference (Deposit): COLORADO DIV. MINES INF. REPTS. AND ANNUAL OPERATOR REPTS.

Reference (Deposit): PRATT, W.P., 1976, PRELIMINARY GEOLOGIC MAP OF THE HERMOSA PEAK QUADRANGLE, DOLORES, SAN JUAN, LA PLATA, AND MONTEZUMA COUNTIES, COLORADO: USGS OF-76-314.

Reference (Production): COLO. DIV. MINES ANNUAL OPERATOR REPTS. (1950-1964 ANNUALS); NELSON-MOORE, 1978, P.398 (CUMULATIVES)

Colorado Mining Photos

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