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Dewey Mine

Past Producer in Valley county in Idaho, United States with commodities Gold, Silver, Titanium
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Public Land Survey System information
  6. Commodities
  7. Materials information
  8. Alteration
  9. Host and associated rocks
  10. Nearby scientific data
  11. Ore body information
  12. Controls for ore emplacement
  13. Economic information about the deposit and operations
  14. Mining district
  15. Mineral rights holdings
  16. Land status
  17. Ownership information
  18. Reserves and resources
  19. Workings at the site
  20. Links to other databases
  21. Bibliographic references
  22. General comments
  23. Reporter information

Geologic information

Identification information

Deposit ID 10144753
MRDS ID W013899
MAS/MILS ID 0160850154
Record type Site
Current site name Dewey Mine
Alternate or previous names Dewey, Dewey-Sunnyside, Dewey Dome, Dewey Hill, Sunnyside, Golden Reef

Geographic coordinates

Point of reference Main Entrance
Geographic coordinates: -115.14565, 44.95768 (WGS84)
Elevation 2316
Location accuracy 10(meters)
Relative position THE PROPERTY IS 40 MILES FROM YELLOW PINE AND 19 MILES FROM THE STIBNITE MINING CAMP. THE ROAD FROM STIBNITE TO THE DEWEY MINE IS PASSABLE BY TWO-WHEEL DRIVE VEHICLES DURING THE SUMMER. THE DEWEY MINE IS LOCATED ON THE WEST SLOPE OF THUNDER MOUNTAIN, AT AN ELEVATION OF 7,500 FT EAST OF THE TOWN OF STIBNITE IN VALLEY COUNTY, ID.

Site location context

Political divisions (FIPS codes)

Valley(county)

Idaho(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Rainbow Peak(quadrangle 1:24,000 scale)

Pistol Creek(quadrangle 1:100,000 scale)

Challis(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Lower Middle Fork Salmon(hydrologic unit)

Salmon(hydrologic accounting unit)

Lower Snake(hydrologic subregion)

Pacific Northwest(hydrologic region)

Federal lands

Payette National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State County
United States Idaho Valley

Public Land Survey System information

Meridian Township Range Section Fraction State
Boise 019 N 011 E 29 C NW Idaho

Comments on the location information

  • NEAR HEAD OF MULE CREEK ON NW SLOPE OF THUNDER MOUNTAIN

Commodities

Commodity Importance
Gold Primary
Silver Secondary
Titanium Critical Tertiary

Materials information

Materials Type of material
Anatase Ore
Ilmenite Ore
Pyrargyrite Ore
Rutile Ore
Chalcedony Gangue
Clinoptilolite Gangue
Fluorite Gangue
Goethite Gangue
Jarosite Gangue
Kaolinite Gangue
Montmorillonite Gangue
Zircon Gangue

Alteration

  • (Local) Complex Clay - Mineral Alteration
  • (Local) Silicification

Analytical data

Result 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

Host and associated rocks

  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock
    Rock unit name Challis Volcanics
    Stratigraphic age (youngest) Eocene
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Felsic Volcanic Rock > Rhyolite
    Rock unit name Challis Volcanics
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Sandstone
    Rock unit name Challis Volcanics
  • Host or associated Host
    Rock type Volcanic Rock (Aphanitic) > Pyroclastic Rock > Volcanic Breccia (Agglomerate)
    Rock unit name Challis Volcanics

Nearby scientific data

Main Entrance (1) -115.14565, 44.95768
ListMap

Economic information

Ore body information

  • Thickness 42.67M
    Length 233.17M
    Width 60.96M

Controls for ore emplacement

  • Faulting
  • Breccia Zone

Comments on the geologic information

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

Economic information about the deposit and operations

Operation type Surface
Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant Yes
Discovery year 1894
Discoverer A. B. And L. J. Caswell, A. O. Huntley
Mining method Open Pit
Plant type Leach
Milling method Heap Leach-Electrowin

Comments on exploration

  • IN 1993 THE COMBINED COMPANIES ENTERED INTO AN AGREEMENT WITH U.S.M.X. TO DO EXPLORATION DRILLING ON THE DEWEY CLAIMS.

Mining district

District name Thunder Mountain District

Mineral rights holdings

Type of mineral rights Located Claim
Type of mineral rights Patented
Type of mineral rights Private Lease

Land status

Ownership category National Forest
Area name Payette National Forest
Ownership category National Primitive Area
Area name Idaho Primitive Area

Ownership information

  • Type Owner
    Owner Thunder Mountain Gold, Inc.
    Interest 50
    Home office Washington
    Year 1996
    First year 1992
  • Type Owner
    Owner Dewey Mining Co.
    Interest 50
    Home office Idaho
    Year 1996
    First year 1992
  • Type Operator
    Owner USMX, Inc.
    Home office Colorado
    Year 1996
    First year 1993
  • Type Owner-Operator
    Owner Dewey Mining Co.
    Interest 100
    Home office Idaho
    Year 1996
    Last year 1992
  • Type Owner-Operator
    Owner Golden Reef Mining Co.
    ID 1001565
    Interest 100
    Home office P. O. Box 8007, Boise, Id 83707
    Year 1981

Comments on the ownership information

  • 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.

Comments on the production information

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

Reserves and resources

  • Type In-situ
    Estimate year 1973
    Inferred 3374000mt ore
    Total resources 3374000mt ore
    Commodity Subtype Grade units Group Importance Year
    Gold 3.105 g/mt Gold Major 1973
    Silver 18.353 g/mt Silver Minor 1973
  • Type In-situ
    Estimate year 1996
    Demonstrated 4264000mt ore
    Total resources 4264000mt ore
    Commodity Subtype Grade units Group Importance Year
    Gold Au 1.71 g/mt Gold Major 1996
  • Type In-situ
    Estimate year 1996
    Total resources 4799007mt ore
    Commodity Subtype Grade units Group Importance Year
    Gold Au 1.61 g/mt Gold Major 1996

Workings at the site

  • Type of workings Surface/Underground
    Length 609.6M
    Overall depth 73.15M
    Field Value
    MAS Development Schedule # 1
    Mining Record # 1
    Status of Mining Method ACTUAL
    Mining Method OPEN PIT
    Capacity 4000
    Capacity Units MT ORE/DAY
    Operating Days per Year 225
    Operating Shifts per Day 2
    Year of Information 1996

Comments on the workings information

  • 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.

Comments on other economic factors

  • PROPERTY COULD BE DEVELOPED INTO MINE BY 1997 WITH AN ESTIMATED 5 YEAR LIFE.

Comments on development

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

Reference information

Bibliographic references

  • 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.

  • Reserve-Resource

    MINERAL RESOURCES OF THE IDAHO PRIMITIVE AREA AND VICINITY, IDAHO, GEOLOGICAL SURVEY BULLETIN 1304, 1973, PG. 60-61, AND 68-76.

  • Production

    SHENON, P. J., AND ROSS, C. P., 1936, IDAHO BUREAU OF MINES AND GEOLOGY PAMPHLET 33, P. 38.

  • 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.

  • Deposit

    USBM, 1975, ACTIVITY OF IDAHO MINING PROPERTIES 1974, USBM, BOISE, IDAHO, 61 P.

  • Reserve-Resource

    RANDOL MINING DIRECTORY, 1996/97, U.S. MINES & MINING COMPANIES, P195.

  • 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.

  • Deposit

    1927 OTHER IDAHO BUREAU OF MINES AND GEOLOGY PAMPH 25

  • Reserve-Resource

    AMERICAN MINES HANDBOOK, 1997, P 271.

  • Deposit

    1936 RECON IDAHO BUREAU OF MINES AND GEOLOGY PAMPH 44

  • Deposit

    RANDOL MINING DIRECTORY, 1994/95, U.S. MINES & MINING COMPANIES, P269.

  • Deposit

    AMERICAN MINES HANDBOOK, 1997, PP. 263, 271.

General comments

Subject category Comment text
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:

Reporter information

Type Date Name Affiliation Comment
Reporter 29-JUL-97 Buckingham, David A. U.S. Bureau of Mines
Reporter 01-APR-74 Miller, Pat J. U.S. Geological Survey

Beyond USGS

Supplemental information added by qvyshift.com. Not part of the original USGS MRDS record.

Current status (per MSHA)

StatusAbandoned since 08/01/1984
MSHA mine ID1001565
Mine name (MSHA)Dewey Mine
Current operatorGolden Reef Mining Company
Mine typeSurface (Metal / non-metal)

MSHA cross-reference per the original MRDS record. Mine status and operator reflect MSHA's last published Mines export (February 2025); MSHA's public bulk feed has been unavailable since, so this may be out of date. See the Mine Data Retrieval System for current status.

Open MSHA's Mine Data Retrieval System for inspections, accidents, and violations for this mine.

External references

Maps centered on this site