Dewey Mine

The Dewey Mine is a gold mine located in Valley county, Idaho at an elevation of 7,598 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: Dewey Mine
Secondary: Dewey
Secondary: Dewey-Sunnyside
Secondary: Dewey Dome
Secondary: Dewey Hill
Secondary: Sunnyside
Secondary: Golden Reef

Commodity

Primary: Gold
Secondary: Silver
Tertiary: Titanium

Location

State: Idaho
County: Valley
District: Thunder Mountain District

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: Payette National Forest

Holdings

Type: Private Lease
Type: Patented
Type: Located Claim

Workings

Type: Surface/Underground

Ownership

Owner Name: Golden Reef Mining Co.
Company ID: 1001565
Percent: 100.0
Home Office: P. O. Box 8007, Boise, Id 83707
Info Year: 1981

Owner Name: Dewey Mining Co.
Percent: 100.0
Home Office: Idaho
Info Year: 1996

Owner Name: USMX, Inc.
Home Office: Colorado
Info Year: 1996
Years: 1993 -

Owner Name: Thunder Mountain Gold, Inc.
Percent: 50.00
Home Office: Washington
Info Year: 1996
Years: 1992 -

Owner Name: Dewey Mining Co.
Percent: 50.00
Home Office: Idaho
Info Year: 1996
Years: 1992 -

Production

Not available

Deposit

Record Type: Site
Operation Category: Past Producer
Plant Type: Leach
Operation Type: Surface
Mining Method: Open Pit
Milling Method: Heap Leach-Electrowin
Discovery Year: 1894
Discovery Method: Ore-Mineral In Place
Years of Production:
Organization:
Significant: Y
Deposit Size: S

Physiography

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

Mineral Deposit Model

Not available

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration: Silicification

Alteration Type: L
Alteration: Complex Clay - Mineral Alteration

Rocks

Name: Clastic Sedimentary Rock
Role: Host
Age Type: Host Rock
Age Young: Eocene

Analytical Data

Analytical Data: ASSAYS OF 7 SAMPLES AVERAGED 0.11 TROY OZ AU AND 0.25 TROY OZ AG/TON. AVERAGE GRADE ALL SEDIMENTS 0.02 OZ AU AND 0.23 OZ AG/TON

Materials

Ore: Pyrargyrite
Ore: Anatase
Ore: Rutile
Ore: Ilmenite
Gangue: Montmorillonite
Gangue: Kaolinite
Gangue: Jarosite
Gangue: Zircon
Gangue: Fluorite
Gangue: Clinoptilolite
Gangue: Chalcedony
Gangue: Goethite

Comments

Comment (Production): 1896 - 1942. TOTAL AU AND AG PRODUCTION ESTIMATED MORE THAN $445,000 (MOSTLY PRIOR TO 1908).

Comment (Deposit): THIS PROPERTY IS ADJACENT TO THE THUNDER MOUNTAIN PROPERTY. USMX FOCUSED DEVELOPMENT DRILLING ON PROPERTY, 1994. OTHER TARGETS IN THE AREA INCLUDED POWDER CABIN; GOLD BUG EXT; & LIGHTNING PEAK:

Comment (Geology): GOLD OCCURS IN DISSEMINATED, VEIN, AND PLACER DEPOSITS. MARGINAL RESERVES TOTAL 3,719,000 TONS AVERAGING 0.13-0.18 OUNCES GOLD PER TON.

Comment (Economic Factors): PROPERTY COULD BE DEVELOPED INTO MINE BY 1997 WITH AN ESTIMATED 5 YEAR LIFE.

Comment (Development): 10 - STAMP MILL; 13 CLAIMS, INCLUDING SEVERAL FRACTIONS, TOTAL 141.26 ACRES ; ECON.COM: 1909 MUDFLOW MAY REMOBILIZE

Comment (Workings): MILL, 2 MAIN HAULAGE LEVELS, 2 INTERMEDIATE LEVELS, SEVERAL ADITS. ONE STOPE WAS 10 SQUARE SETS HIGH, 46 SQUARE SETS LONG. ALL STOPES WERE BIG.

Comment (Geology): CARBONACEOUS MUDFLOW BRECCIA AVERAGED 0.05 OZ AU AND 0.18 OZ AG/TON; CARBONACEOUS VOLCANIC SANDSTONE AVERAGED 0.05 OZ AU AND 0.32 OZ AG/TON.

Comment (Location): NEAR HEAD OF MULE CREEK ON NW SLOPE OF THUNDER MOUNTAIN

Comment (Exploration): IN 1993 THE COMBINED COMPANIES ENTERED INTO AN AGREEMENT WITH U.S.M.X. TO DO EXPLORATION DRILLING ON THE DEWEY CLAIMS.

Comment (Ownership): IN MARCH OF 1992 THUNDER MOUNTAIN GOLD AND DEWEY MINING COMPANY ENTERED INTO AN AGREEMENT TO COMBINE THE MAJORITY OF THE CLAIM GROUPS IN THE THUNDER MOUNTAIN GOLD MINING DISTRICT, INTO THE THUNDER MOUNTAIN PROJECT. THE DEWEY WILL BE THE FIRST MINE. USMX (THE LESSEE) WILL OPERATE THE MINE USING A CONTRACT MINER.

References

Reference (Deposit): AMERICAN MINES HANDBOOK, 1997, PP. 263, 271.

Reference (Deposit): RANDOL MINING DIRECTORY, 1994/95, U.S. MINES & MINING COMPANIES, P269.

Reference (Reserve-Resource): AMERICAN MINES HANDBOOK, 1997, P 271.

Reference (Reserve-Resource): RANDOL MINING DIRECTORY, 1996/97, U.S. MINES & MINING COMPANIES, P195.

Reference (Deposit): CATER, F. W., AND OTHERS, 1973, MINERAL RESOURCES OF THE IDAHO PRIMITIVE AREA AND VICINITY, IDAHO: U. S. GEOLOGICAL SURVEY BULL. 1304, 431 P.

Reference (Deposit): 1936 RECON IDAHO BUREAU OF MINES AND GEOLOGY PAMPH 44

Reference (Reserve-Resource): MINERAL RESOURCES OF THE IDAHO PRIMITIVE AREA AND VICINITY, IDAHO, GEOLOGICAL SURVEY BULLETIN 1304, 1973, PG. 60-61, AND 68-76.

Reference (Deposit): 1927 OTHER IDAHO BUREAU OF MINES AND GEOLOGY PAMPH 25

Reference (Deposit): USBM, 1975, ACTIVITY OF IDAHO MINING PROPERTIES 1974, USBM, BOISE, IDAHO, 61 P.

Reference (Deposit): ROSS, C. P., 1927 , ORE DEPOSITS IN THE TERTIARY LAVA IN THE SALMON RIVER MOUNTAINS, IDAHO: IDAHO BUREAU OF MINES AND GEOLOGY PAMPHLET 25 , 20 P.

Reference (Production): SHENON, P. J., AND ROSS, C. P., 1936, IDAHO BUREAU OF MINES AND GEOLOGY PAMPHLET 33, P. 38.

Reference (Deposit): SHENON, P. J., AND ROSS, C. P., 1936, GEOLOGY AND ORE DEPOSITS NEAR EDWARDSBURG AND THUNDER MOUNTAIN, IDAHO: IDAHO BUREAU OF MINES AND GEOLOGY PAMPHLET 44, 45 P.

Idaho Gold

"Where to Find Gold in Idaho" 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 Idaho. Read more: Where to Find Gold in Idaho.