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Little Boulder Creek

Prospect in Custer county in Idaho, United States with commodities Molybdenum, Tungsten, Lead, Zinc, Gold
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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. Host and associated rocks
  9. Nearby scientific data
  10. Ore body information
  11. Economic information about the deposit and operations
  12. Mining district
  13. Mineral rights holdings
  14. Land status
  15. Ownership information
  16. Reserves and resources
  17. Workings at the site
  18. Links to other databases
  19. Bibliographic references
  20. Reporter information

Geologic information

Identification information

Deposit ID 10192485
MRDS ID W014120
MAS/MILS ID 160370455
Record type Site
Current site name Little Boulder Creek
Alternate or previous names Boulder Creek Molybdenum Deposit, Little Boulder Creek Moly Deposit, Baker Lake Moly Deposit, Fuller and Baker, Boulder Creek, Baker Lake

Geographic coordinates

Point of reference Ore Body
Geographic coordinates: -114.5575, 44.0553 (WGS84)
Elevation 2600
Location accuracy 10(meters)
Relative position 33.5 MI SSW OF CHALLIS

Site location context

Political divisions (FIPS codes)

Custer(county)

Idaho(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Boulder Chain Lakes(quadrangle 1:24,000 scale)

White Cloud Peaks(quadrangle 1:100,000 scale)

Challis(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper Salmon(hydrologic unit)

Salmon(hydrologic accounting unit)

Lower Snake(hydrologic subregion)

Pacific Northwest(hydrologic region)

Federal lands

Sawtooth National Forest(National Forest)

National Forest FS(Type of land area)

FS(Federal land areas administered by FS)

Cecil D. Andrus-White Clouds Wilderness(Wilderness)

Wilderness FS(Type of land area)

FS(Federal land areas administered by FS)

Geographic areas

Country State County
United States Idaho Custer

Public Land Survey System information

Meridian Township Range Section Fraction State
Boise 008 N 016 E 3 Idaho

Commodities

Commodity Importance
Molybdenum Primary
Tungsten Critical Tertiary
Lead Tertiary
Zinc Critical Tertiary
Gold Tertiary

Materials information

Materials Type of material
Molybdenite Ore
Galena Ore
Sphalerite Ore
Calcite Gangue
Feldspar Gangue
Arsenopyrite Unknown
Biotite Unknown
Chlorite Unknown
Diopside Unknown
Epidote Unknown
Garnet Unknown
Hornblende Unknown
Pyrite Unknown
Quartz Unknown
Scheelite Unknown
Tremolite Unknown

Host and associated rocks

  • Host or associated Host
    Rock type
    Rock unit name Wood River Formation
    Stratigraphic age (youngest) Pennsylvanian
  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Limestone
    Stratigraphic age (youngest) Pennsylvanian
  • Host or associated Host
    Rock type Metamorphic Rock > Metasedimentary Rock > Quartzite
  • Host or associated Host
    Rock type Metamorphic Rock > Skarn (Tactite)
    Stratigraphic age (youngest) Eocene
  • Host or associated Associated
    Rock type Volcanic Rock (Aphanitic) > Intermediate Volcanic Rock > Andesite

Nearby scientific data

Ore Body (1) -114.5575, 44.0553
ListMap

Economic information

Ore body information

  • Strike N20W
    Dip 80E
    Thickness 1000M
    Length 149M
    Width 150M
    Depth to top 2M
    Field Value
    MAS Matrix # 1
    MAS Column # 3
    Type of Orebody #1 STOCKWORK
    Shape of Orebody #1 TABULAR
    Primary mode of Origin HYDROTHERMAL
    Secondary mode of Origin CONT METASOMATIC
    Primary Ore Control FAULTING
    Secondary Ore Control IGNEOUS
    Degree of Wallrock Alter. SLIGHT
    Type of Wallrock Alter. #1 SILICIFICATION
    Type of Wallrock Alter. #2 PROPYLITIC
    Type of Wallrock Alter. #3 CARBONATE SILIC
    Strike And Dip N20W:80E
    Minimum Depth to Top 0
    Avg. Thick. Unconsol. Mat. 2
    Min. Thick. Unconsol. Mat. 0
    Date of Last Modification 830316
  • Strike N20W
    Dip 80E
    Thickness 300M
    Length 1250M
    Width 200M
    Depth to top 2M
    Field Value
    MAS Matrix # 2
    MAS Column # 3
    Type of Orebody #1 STOCKWORK
    Shape of Orebody #1 TABULAR
    Primary mode of Origin HYDROTHERMAL
    Secondary mode of Origin CONT METASOMATIC
    Primary Ore Control FAULTING
    Secondary Ore Control IGNEOUS
    Degree of Wallrock Alter. SLIGHT
    Type of Wallrock Alter. #1 SILICIFICATION
    Type of Wallrock Alter. #2 PROPYLITIC
    Type of Wallrock Alter. #3 CARBONATE SILIC
    Strike And Dip N20W:80E
    Minimum Depth to Top 0
    Avg. Thick. Unconsol. Mat. 2
    Min. Thick. Unconsol. Mat. 0
    Date of Last Modification 830316
  • Strike N20W
    Dip 80E
    Thickness 175M
    Length 760M
    Width 125M
    Depth to top 2M
    Field Value
    MAS Matrix # 3
    MAS Column # 3
    Type of Orebody #1 STOCKWORK
    Shape of Orebody #1 TABULAR
    Primary mode of Origin HYDROTHERMAL
    Secondary mode of Origin CONT METASOMATIC
    Primary Ore Control FAULTING
    Secondary Ore Control IGNEOUS
    Degree of Wallrock Alter. SLIGHT
    Type of Wallrock Alter. #1 SILICIFICATION
    Type of Wallrock Alter. #2 PROPYLITIC
    Type of Wallrock Alter. #3 CARBONATE SILIC
    Strike And Dip N20E:80E
    Minimum Depth to Top 0
    Avg. Thick. Unconsol. Mat. 2
    Min. Thick. Unconsol. Mat. 0
    Date of Last Modification 830316
  • Strike N20W
    Dip 80E
    Thickness 400M
    Length 1150M
    Width 325M
    Depth to top 2M
    Field Value
    MAS Matrix # 4
    MAS Column # 3
    Type of Orebody #1 STOCKWORK
    Shape of Orebody #1 TABULAR
    Primary mode of Origin HYDROTHERMAL
    Secondary mode of Origin CONT METASOMATIC
    Primary Ore Control FAULTING
    Secondary Ore Control IGNEOUS
    Degree of Wallrock Alter. SLIGHT
    Type of Wallrock Alter. #1 SILICIFICATION
    Type of Wallrock Alter. #2 PROPYLITIC
    Type of Wallrock Alter. #3 CARBONATE SILIC
    Strike And Dip N20W:80E
    Minimum Depth to Top 0
    Avg. Thick. Unconsol. Mat. 2
    Min. Thick. Unconsol. Mat. 0
    Date of Last Modification 830316
  • Area 700HA
    Field Value
    Total Surface Area (HA) 700
    Date of Last Modification 910418

Comments on the geologic information

  • THE BOULDER CREEK DEPOSIT IS A STOCKWORK MOLY DEPOSIT. THE WOOD RIVER SEDIMENTS WERE FRACTURED BY A ANCESTRAL LITTLE BOULDER FAULT ZONE, CREATING A ZONE OF WEAKNESS WHEREBY THE WHITE CLOUD STOCK WAS INTRUDED. THE SEDIMENTS WERE METAMORPHOSED AND ALTEREDY BY FLUIDS FROM THE STOCK. IN MORE INTENSLEY FRACTURED ZONES(NORTH AND SOUTH ORE ZONES) THE FRACTURES WERE HEALED BY MOLY RICH QUARTZ VEINLETS. SUBSEQUENT MOVEMENT ON THE LITTLE BOULDER FAULT (AND OTHER FAULTS) HAS PRODUCED THE PRESENT ORE BODY SHAPE. MOST OF THE MINERALIZATION IS CONFINED TO A DIOPSIDE RICH TACTITE (ZONE NEAREST TO INTRUSIVE). MOST OF THE MOLY(95%) IS FOUND IN QUARTZ RICH VEINLETS. MINOR AMOUNTS OF MOLY ARE DISSEMINATED THROUGHOUT THE ROCK. THE GRADE OF MINERALIZATION IS VERY UNIFORM ON THE SURFACE AND AT DEPTH. GRADE GRADUALLY DROPS OFF AS THE DISTANCE FROM THE INTRUSIVE INCREASES.
  • MOLYBDENITE IS THE SOLE ORE MINERAL. SCHEELITE IS FOUND THROUGHOUT THE DEPOSIT(.007 WO3), BUT IN AMOUNTS TOO SMALL TO RECOVER. A HIGHER GRADE SCHEELITE AREA (GRADE UNKNOWN) IS PRESENT IN THE BANDED TACTITE ZONE ON THE NE EDGE OF THE PROPOSED PIT. THIS MAY BE OF HIGH ENOUGH GRADE TO BE RECOVERABLE, BUT NOT ENOUGH INFORMATION IS KNOWN ABOUT IT AS YET.

Economic information about the deposit and operations

Operation type Surface
Development status Prospect
Commodity type Metallic
Deposit size Small
Significant Yes
Discovery year 1922
Milling method Flotation

Mining district

District name Little Boulder

Mineral rights holdings

Type of mineral rights Located Claim

Land status

Ownership category National Forest
Area name Challis National Forest

Ownership information

  • Type Owner
    Owner Asarco (American Smelting And Refining Co.)
    Interest 100
    Home office New York
    Year 1982
  • Type Owner
    Owner Grupo Mexico
    Interest 100
    Home office Avenida Baja California 200 Col. Roma Sur Mexico D.F. MEX 06760 Mexico
    First year 1999

Comments on the ownership information

  • PROPERTY CONSISTS OF 51 UNPATENTED CLAIMS IN THE SAWTOOTH NATIONAL RECREATION AREA.

Comments on the production information

  • ASARCO FROM 1968-1972 CONDUCTED AN INTENSIVE EXPLORATION PROGRAM ON THE PROPERTY. BUT ENVIRONMENTAL OBJECTIONS HAVE PREVENTED ANY FUTHER MAJOR EXPLORATION WORK. ONLY ASSESSMENT WORK HAS BEEN DONE ON THE CLAIMS SINCE 1972.

Reserves and resources

  • Type In-situ
    Estimate year 1979
    Measured 167000000mt ore
    Demonstrated 167000000mt ore
    Total resources 167000000mt ore
    Commodity Subtype Grade units Group Importance Year
    Molybdenum MoS2 0.15 wt-pct Molybdenum Major 1979
  • Type In-situ
    Estimate year 1974
    Measured 123000000mt ore
    Demonstrated 123000000mt ore
    Total resources 123000000mt ore
    Commodity Subtype Grade units Group Importance Year
    Molybdenum MoS2 0.15 wt-pct Molybdenum Major 1974

Comments on the reserve resource information

  • CAVANAUGH HAS 149000000 MT IN NORTH ORE ZONE AT .15% MOS2 AND 18000000 IN SOUTH ORE ZONE AT .15% MOS2. TSCHANZ HAS 91000000 MT IN NORTH ORE ZONE AT .16% MOS2. AND 32000000 MT IN SOUTH ORE ZONE AT .12% MOS2.
  • BECAUSE OF CONFLICTING TONNAGE FIGURES AND LACK OF INFORMATION ON HOW THE FIGURES WERE CALCULATED, NEW ONES WERE CALCULATED. FOR A COMPLETE DESCRIPTION OF HOW RESOURCE DATA WAS DERIVED SEE APPENDIX B-2 OF REPORT. MATRIX ONE (NORTH ORE ZONE) DEALS WITH ROCK GREATER THAN .15% MOS2 (.165% ON THE AVERAGE). 90% ROCK IS EXPOSED IN OUTCROP, OR IN DRILL HOLE, PROJECTED TO A DEPTH OF 7700 FEET THE BOTTOM ELEVATION OF DEEPEST DRILL HOLE. THE OTHER PROBABILITY LEVELS (75-25%) ARE BASED ON DEEPER PROJECTIONS OF THE ORE, AND ON PROJECTIONS OF THE EXPOSED ORE TO THE NORTH AND SOUTH(AREAS COVERED BY VOLCANICS AND TALUS.) MATRIX 2 (NORTH ORE ZONE) DEALS WITH ROCK GREATER THAN .05% MOS2 (.10% ON THE AVERAGE). THIS IS ROCK THAT MUST BE REMOVED IN ORDER TO EXTRACT THE 90% PROB ORE OF MATRIX 1. MATRIX 3 (SOUTH ORE ZONE) DEALS WITH ROCK GREATER THAN .15% (.165% ON THE AVERAGE). MATRIX 4 (NORTH ORE ZONE) IS THE TONNAGE PROPOSED FOR MINING IT IS MATRIX ONE 90% PROB ORE, PLUS THE MINERALIZED ROCK THAT MUST BE REMOVED IN ORDER TO EXTRACT THE 90% PROB. ORE. THE MINERALIZED ROCK THAT MUST BE REMOVED IS COMPOSED OF MATRIX 2 LOW GRADE ROCK AND SOME OF MATRIX ONE 75% PROB ROCK (19000000 MT)

Workings at the site

  • Type of workings Surface
    Area 108HA
    Field Value
    MAS Development Schedule # 1
    Mining Record # 1
    Status of Mining Method PROPOSED
    Mining Method OPEN PIT
    Percent Waste Rock 55.7
    Avg. Overburden Thickness 2
    Primary Material Cover SAND, GRAVEL
    Hardness of Ore HARD ROCKS
    Avg. Bench Height (meters) 15
    Max. Pit Slope (degrees) 45
    Capacity 22680
    Capacity Units MT ORE/DAY
    Preprod. Stripping Vol. 926.119
    Unit Production Cost 2.83
    Units of Production $/MT ORE
    Operating Days per Year 350
    Operating Shifts per Day 3
    Year of Information 1982

Reference information

Bibliographic references

  • Deposit

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

  • Reserve-Resource

    TSCHANZ, C.M., 1974, MINERAL RESOURCES OF THE EASTERN PART

  • Reserve-Resource

    U.S.G.S. OPEN FILE REPORT, 648 P.

  • Deposit

    ANDERSON, 1952, MULTIPLE EMPLACEMENT OF THE IDAHO BATHOLITH, JOUR. OF GEOLOGY, V. 60, P 255-265.

  • Deposit

    ARMSTRONG, 1978, K-AR DATES FOR MINERALIZATION IN THE WHITE CLOUD-CANNIVAN PORPHYRY MOLYBDENUM BELT OF IDAHO AND MONTANA: ECON. GEOL., V. 73, NO. 1 P 94-108

  • Deposit

    BARNES, F.D., 1971, A SUMMARY OF GEOLOGY, KNOWN MINERAL RESOURCES, AND MINING HISTROY OF THE WHITE CLOUD MTS., ID., U.S. BLM REPORT.

  • Deposit

    BALLA, J.C., 1981, PERSONAL COMMUN., ASARCO INC.

  • Deposit

    BALLA, J.C., 1980, GEOLOGY OF THE LITTLE BOULDER CREEK DEPOSIT, CUSTER COUNTY, IDAHO(ABS.) PROCEEDINGS OF THE SYMPOSIUM ON MINERAL DEPOSITS OF THE PACIFIC N.W., U.S.G.S. OPEN FILE REPORT, 81-355.

  • Deposit

    BENNETT, E.H., 1981, IDAHO BUREAU OF MINES AND GEOLOGY, PERSONAL COMMUN.

  • Deposit

    BENNETT, E.H., 1973, PETROLOGY AND TRACE ELEMENT DISTRIBUTION OF THE WHITE CLOUD STOCK: PHD THESIS, UNIV. OF IDAHO, 172 P.

  • Deposit

    BLM, BOISE, IDAHO, 1981, MASTER TITLE PLATS.

  • Deposit

    DWYER, CHARLES, 1970, A PRELIMINARY STUDY OF AERIAL TRAMWAY ACCESS AND TRANSPORT FOR A PROPOSED MINING OPERATION IN THE CHALLIS NATIONAL FOREST, A USFS REPORT.

  • Deposit

    CAVANAUGH, PAT, 1979, THE GEOLOGY OF THE LITTLE BOULDER CREEK MOLYBDENUM DEPOSIT, CUSTER COUNTY, IDAHO, M.S. THESIS, UNIV. OF MONTANA.

  • Deposit

    CLARK, K.F., 1972, STOCKWORK MOLYBDENUM DEPOSITS IN THE WESTERN CORDILLERA OF NORTH AMERICA: ECON. GEOL., VOL 67, NO. 6, P. 731-758.

  • Deposit

    CREASEY,S.C., 1944, PRELIMINARY REPORT ON THE BOULDER CREEK (BRONTON) MOLYBDENUM DEPOSIT, CUSTER COUNTY, IDAHO, U.S.G.S. WAR MINERALS REPORT (UNPUBLISHED).

  • Deposit

    GREEN, W.R.,1972, DELINEATION OF MINERAL BELTS OF NORTHERN AND CENTRAL IDAHO: IDAHO BUR. OF MINES AND GEOLOGY INFO. CIRCULAR 22, 8P.

  • Deposit

    HAYDEN, TERRY, 1981, PERSONAL COMMUN., PLACER AMAX INC.

  • Deposit

    JONES, JEFF, 1981, SAWTOOTH NRA, PERSONAL COMMUN.

  • Deposit

    KESTON, NORMAN, 1970, 'THE WHITE CLOUDS ISSUE', WESTERN MINING NEWS.

  • Deposit

    KING, R.U., 1970, MOLYBDENUM IN THE U.S.: USGS MINERAL INV. RESOURCES MAP MR-55, 21P.

  • Deposit

    KIRKEMO, J., 1965, INVESTIGATIONS OF MOLYBDENUM DEPOSITS IN THE CONTERMINOUS U.S., 1942-1960:USGS BULL. 1182-E P. E54-55.

  • Deposit

    MARVIN, R.F., 1973, LATE CRETACEOUS AGE FOR MOLYBDENITE MINERALIZATION IN CUSTER CO., IDAHO:ISOCHRON/WEST, NO. 7 P.1

  • Deposit

    MINARIK, ROD, 1982, CLIMAX CORP., PERSONAL COMMUN.

  • Deposit

    MOTZER, WILLIAM, 1978, VOLCANIC STRATIGRAPHY OF AN AREA EAST OF THE WHITE CLOUD PEAKS, SAWTOOTH NRA, CUSTER CO., IDAHO, M.S. THESIS, UNIV OF IDAHO.

  • Deposit

    PAY DIRT, 1981,'ASARCOS RENEWED INTEREST IN IDAHO MOLY REKINDLES OPPOSITION', AUGUST 1981.

  • Deposit

    ROSS, C.P., 1937, GEOLOGY AND ORE DEPOSITS OF THE BAYHORSE REGION, CUSTER CO, IDAHO: USGS BULL. 877, 161 P.

  • Deposit

    SAVAGE, C.N., 1970, EVALUATION OF MINERALS AND MINERAL POTENTIAL OF THE SALMON RIVER DRAINAGE BASIN IN IDAHO: ID. BUREAU OF MINES AND GEOLOGY PAMPHLET 147, 64 P.

  • Deposit

    SHAFFER, LYSLE, 1943, BOULDER CREEK MOLYBDENUM DEPOSIT, USBM WAR MINERALS REPORT, UNPUBLISHED.

  • Deposit

    THE MINING RECORD, 1981,'AMERICAN MINE CLAIMS STATUS IS UNCHANGED', AUGUST 1981.

  • Deposit

    THE MINING RECORD, 1981, 'ASARCO WILL NOT SUBMIT OPERATING PLAN', NOVEMBER 1981.

  • Deposit

    TSCHANZ, C.M., 1986, MINERAL RESOURCES OF THE EASTERN PART OF THE SAWTOOTH N.R.A., CUSTER AND BLAINE COS., IDAHO: U.S. GEOLOGICAL SURVEY BULLETIN 1545-E, P. 243.

  • Deposit

    USBM, MINERAL PROPERTY FILE, WFOC, 0160370455.

  • Deposit

    VISGER, FRANK, 1974, THE GEOLOGY OF THE UNCLE JESS MOLYBDENITE DEPOSIT, CUSTER CO., IDAHO, M.S. THESIS, EASTERN WASHINGTON STATE COLLEGE.

  • Deposit

    KING, R.U., 1964, IDAHO BUREAU OF MINES AND GEOLOGY SPECIAL REPORT NO. 1, P 137.

  • Deposit

    CAVANAUGH, PAT, 1982, PERSONAL COMMUNICATION

  • Deposit

    U.S.B.M., MINE MAP FILE, SEQ NO. 0160370455, W.F.O.C.

Reporter information

Type Date Name Affiliation Comment
Reporter 1975-10-01 Murphy, Lyn S.; Miller, Pat U.S. Geological Survey
Reporter 1995-03-01 Benjamin U.S. Bureau of Mines

Beyond USGS

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

Operator history (post-MRDS)

MRDS records operators as of each record's last update (≤ 2019). Some of the operators listed here have since changed hands or dissolved:

  • Asarco (American Smelting And Refining Co.) — acquired by Asarco LLC, subsidiary of Grupo México (2009)
    American Smelting and Refining Co. Filed Chapter 11 in 2005; acquired out of bankruptcy by Grupo México in 2009.

Curated by qvyshift.com from publicly-reported M&A activity (SEC filings, press releases, USGS Mineral Yearbooks). Not authoritative — verify against primary sources before relying on it. The MSHA panel above is the current authoritative source for actively-permitted mines.

Maps centered on this site