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Brown's Lake

Past Producer in Beaverhead county in Montana, United States with commodities Tungsten, Copper, Molybdenum
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Geologic information

Identification information

Deposit ID 10055833
MRDS ID SP00032
MAS/MILS ID 0300010616
Record type Site
Current site name Brown's Lake
Alternate or previous names Ivanhoe, Lost Creek, Browns Lake Mine, Lentung

Geographic coordinates

Geographic coordinates: -112.836, 45.521 (WGS84)
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Geographic areas

Country State County
United States Montana Beaverhead

Public Land Survey System information

Meridian Township Range Section Fraction State
Montana Principal 004S;003S 010W;010W 03,04,32,33,34 Montana

Comments on the location information

  • POINT OF REFERENCE IS CENTROID; 100

Commodities

Commodity Importance
Tungsten Primary
Copper Secondary
Molybdenum Tertiary

Comments on the commodity information

  • SCHEELITE CONTAINS APPRECIABLE POWELLITE

Materials information

Materials Type of material
Chalcopyrite Ore
Powellite Ore
Scheelite Ore
Bornite Ore
Covellite Ore
Malachite Ore
Pyrrhotite Ore
Epidote Gangue
Garnet Gangue
Quartz Gangue
Magnetite Gangue
Biotite Gangue
Pyrite Gangue

Alteration

  • (Local) Chloritization
  • (Local) Oxidation
  • (Local) Skarn

Analytical data

Result EASTERN ORE ZONE AVERAGES 0.59% WO3, WESTERN ORE ZONE AVERAGES 0.17% WO

Mineral occurrence model information

Model code 42
USGS model code 14a
Deposit model name W skarn

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Granite
    Stratigraphic age (youngest) Late Permian
    Stratigraphic age (youngest) Mississippian
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Shale
  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Quartz Monzonite
  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite
  • Host or associated Host
    Rock type Sedimentary Rock > Carbonate > Limestone
    Rock unit name Amsden Formation

Nearby scientific data

(1) -112.836, 45.521
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Geologic structures

Type Description Terms
Local Contact Metamorphic Zone
Local Pioneer Batholith

Ore body information

  • General form TABULAR AND IRREGULAR
    Strike N 55 W AVERAGE
    Dip 30 TO 37 S
    Thickness 22.86M
    Depth to top 0M
    Width 35.66M
    Length 304.8M

Controls for ore emplacement

  • Scheelite Disseminated Through Tactite And Is Present In Hornfels:

Comments on the geologic information

  • FORMATION NAME IS AMSDEN. . MAJOR POST-ORE GEOLOGIC EVENT WAS NORMAL FAULTING.. LOCAL DEEP GLACIAL MORAINE COVER.

Economic information

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Significant Yes
Discovery year 1941
Year of first production 1953
Year of last production 1958

Mining district

District name Lost Creek
District name Brown's Lake
District name Rock Creek District

Land status

Ownership category Mixed

Ownership information

  • Type Owner-Operator
    Owner American Alloy Metals, Inc.
  • Type Operator
    Owner General Electric
  • Type Owner
    Owner Garrand Corp.
    Home office 10 Exchange Place, Salt Lake City, Utah

Production statistics

  • Year 1956
    Period 1952-56
    Material ORE
    Accuracy Accurate
    Description Cp_Grade: ^0.18% W03
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary WO3 Ore Tungsten Tungsten 0wt-pct
  • Year 1958
    Period 1953-58
    Material ORE
    Accuracy Accurate
    Description Cp_Grade: ^0.35% W03
    Importance Item Commodity Group Amount recovered Grade Recovery percentage
    Primary WO3 Ore Tungsten Tungsten 0wt-pct

Reserves and resources

  • Type In-situ
    Estimate year 1986
    Total resources 1,587,000mt ore
    Commodity Subtype Grade units Group Importance Year
    Tungsten Wo3 0.5 wt-pct Tungsten Major 1986

Comments on the reserve resource information

  • "R" DENOTES IN SITU RESOURCES - QUANTITIES OF ECONOMIC INTEREST FOR THE NEXT FEW DECADES. "1" DENOTES KNOWN DEPOSITS WITH RELIABLE ESTIMATES. "E" DENOTES ECONOMICALLY EXPLOITABLE. "M" DENOTES MARGINALLY ECONOMIC. "2" DENOTES EXTENSIONS OF KNOWN DEPOSITS AND NEWLY DISCOVERED DEPOSITS - PRELIMINARY RESULTS. 1985 FIGURES COME FROM UNPUBLISHED PROPRIETARY INFORMATION. IN EXTENSION TO ORIGINAL ORE BODY, NOW LARGELY MINED OUT. PROBABLY EQUAL TO OR EXCEEDING PAST PRODUCTION.

Workings at the site

  • Type of workings Surface/Underground
    Length 228.6M
    Overall depth 54.86M
    Overall length 243.84M
    Overall width 45.72M

Comments on the workings information

  • MINE DEVELOPED BY DRIFTS, RAISE, AND OPEN PIT

Comments on development

  • NATURE OF THE DISCOVERY WAS BY CONVENTIONAL PROSPECTING. NON-GEOLOGIC CONSTRAINTS ON DEVELOPMENT OR EXPANSION IN 1-5 YEARS WERE DUE TO THE MINE PLANT, PROCESSING, AND THE MARKET. KNOWN EXTENSION OF ORE BODY PROBABLY WILL BE DEVELOPED UNDER BETTER ECONOMIC CONDITIONS. PRODUCT UPGRADED BEFORE EXPORT: CONCENTRATE.

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Mineral Resources Data System MRDS SP00032
USGS International Strategic Minerals Inventory ISMI W0109
USGS Mineral Resources Data System MRDS M060802

Bibliographic references

  • Deposit

    PATTEE, E.C., 1960, TUNGSTEN RESOURCES OF MONTANA: DEPOSITS OF THE MOUNT TORREY BATHOLITH BEAVERHEAD COUNTY, U.S. BUREAU OF MINES, REPORT OF INVESTIGATION 5552, 41P.

  • Production

    DMEA FILES

  • Deposit

    MYERS, W.B., 1952, GEOLOGY AND MINERAL DEPOSITS OF THE NORTHWEST QUARTER OF WILLIS QUADRANGLE AND ADJACENT BROWN'S LAKE AREA; BEAVERHEAD COUNTY, MONTANA, U.S. GEOLOGICAL SURVEY, OPEN FILE REPORT, P. 18.

  • Production

    INTERNATIONAL STRATEGIC MINERALS INVENTORY RECORD W109

  • Deposit

    GEACH, R.D., 1972, MINES AND MINERAL DEPOSITS (EXCEPT FUELS), BEAVERHEAD COUNTY, MONTANA, MONTANA BUREAU OF MINES AND GEOLOGY, BULLETIN 85, 194 P.

  • Deposit

    DMEA 1951X

  • Deposit

    DMEA 2292

  • Deposit

    DMA-148

General comments

Subject category Comment text
Deposit AT WEST END OF CUT TWO ORE BODIES ARE SEPARATED BY BARREN MARBLE UP TO 16 FT. THICK. AT EAST END THE ORE BODIES ARE FAULTED TOGETHER. AN ISOLATED, 13-FT. THICK ORE BED IS 90-FT. STRATIGRAPHICALLY ABOVE THE MAIN ORE BODY.
Deposit DEPTH OF COVER: 0-60 FEET (APPROXIMATELY). DEPTH OF UNCONSOLIDATED COVER: 0-20 FEET
Deposit Discovery Year: ORIGINALLY LOCATED AS A COPPER PROPERTY

Reporter information

Type Date Name Affiliation Comment
Reporter 01-SEP-85 Hobbs, Warren S. U.S. Geological Survey
Reporter 01-JUL-80 Loen, Jeffrey S. (Pearson, Robert C.) U.S. Geological Survey
Updater 06-DEC-10 Causey, J. Douglas U.S. Geological Survey combined info from Dep_ID 10042779 (M060802) and deleted that record
Reporter 29-JAN-92 Avery, Dale U.S. Bureau of Mines