Grey Claim

The Grey Claim is a chromium mine located in Napa county, California at an elevation of 1,201 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: Grey Claim

Commodity

Primary: Chromium
Tertiary: Rhodium
Tertiary: Iridium
Tertiary: Palladium
Tertiary: Platinum
Tertiary: Ruthenium

Location

State: California
County: Napa

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

Not available

Workings

Type: Surface/Underground

Ownership

Owner Name: W. B. Shepherd
Years: 1942 -

Owner Name: Anglo American Mining Co.
Years: 1942 -

Production

Year: 1918
Material type: ORE
Description: Ap_Grade: ^38-45% Cr2o3

Deposit

Record Type: Site
Operation Category: Past Producer
Operation Type: Unknown
Years of Production:
Organization:
Significant: N
Deposit Size: S

Physiography

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

Mineral Deposit Model

Model Name: Podiform chromite (minor)

Orebody

Form: CLOSELY PACKED LENSES

Structure

Type: L
Description: Shear Zone

Alterations

Not available

Rocks

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

Name: Peridotite
Role: Associated
Age Type: Associated Rock Unit
Age Young: Late Jurassic

Name: Peridotite
Role: Associated
Age Type: Associated Rock
Age Young: Late Jurassic

Analytical Data

Analytical Data: RH=11 PPB.
Analytical Data: RU=200 PPB
Analytical Data: IR=56 PPB
Analytical Data: PD=6 PPB
Analytical Data: 1 PGE ANALYSIS: PT=124 PPB

Materials

Ore: Chromite
Gangue: Olivine

Comments

Comment (Location): UTM GIVEN IS FOR PGE SAMPLE SITE COLLECTION. LAT/LONG GIVEN IS FOR PROSPECT SYMBOL IN NW/4 SEC. 13. UTM FOR THIS LOCATION IS 4295650N, 554660E

Comment (Production): CUTS BADLY CAVED IN 1942 AND NO ORE SEEN IN PLACE, BUT ABOUT 200 TONS OF ORE WERE STACKED NEAR WORKINGS

Comment (Deposit): AGGREGATE OF LENSES EXTENDS FOR 25 FT AND IS 3-6 FT WIDE AND 30 FT DEEP IN A SHEAR ZONE.

Comment (Workings): 8 FT SHAFT AT THE BOTTOM OF AN OPEN CUT 20 FT DEEP. TOPOGRAPHIC MAP SHOWS SEVERAL PROSPECT SYMBOLS IN AREA

References

Reference (Deposit): CARLSON, C.A., AND OTHERS, 1985, ANALYSES FOR PLATINUM-GROUP ELEMENTS IN SAMPLES FROM PODIFORM CHROMITE DEPOSITS, CALIFORNIA AND OREGON: U.S. GEOLOGICAL SURVEY OPEN-FILE REPORT 85-442, 14 P.

Reference (Deposit): DOW, D.H., AND THAYER, T.P., 1946, GEOLOGICAL INVESTIGATIONS OF CHROMITE IN CALIFORNIA: CALIFORNIA DIVISION OF MINES BULLETIN 134, PT. 2, CH. 1, P. 21.

Reference (Deposit): AVERITT, PAUL, 1945, QUICKSILVER DEPOSITS OF THE KNOXVILLE DISTRICT, NAPA, YOLO, AND LAKE COUNTIES, CALIFORNIA: CALIFORNIA JOURNAL OF MINES AND GEOLOGY V. 41, NO. 2, PL. 6.

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.