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Letterman Mine

Past Producer in Sanders county in Montana, United States with commodities Gold, Lead, Silver, Copper
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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. Geologic structures
  11. Ore body information
  12. Controls for ore emplacement
  13. Economic information about the deposit and operations
  14. Mining district
  15. Land status
  16. Ownership information
  17. Links to other databases
  18. Bibliographic references
  19. General comments
  20. Reporter information

Geologic information

Identification information

Deposit ID 10019046
MRDS ID DC08401
Record type Site
Current site name Letterman Mine
Alternate or previous names Montana Premier Mine

Geographic coordinates

Geographic coordinates: -114.89543, 47.42849 (WGS84)
Elevation 853
Relative position 2 MI S OF PLAINS

Site location context

Political divisions (FIPS codes)

Sanders(county)

Montana(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

Plains(quadrangle 1:24,000 scale)

Plains(quadrangle 1:100,000 scale)

Wallace(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Lower Clark Fork(hydrologic unit)

Pend Oreille(hydrologic accounting unit)

Kootenai-Pend Oreille-Spokane(hydrologic subregion)

Pacific Northwest(hydrologic region)

Federal lands

Lolo 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 Montana Sanders

Public Land Survey System information

Meridian Township Range Section Fraction State
Montana Principal 019N;020N 026W;026W 03,10;34 Montana

Comments on the location information

  • ABUTS, IN PART, THE WEST SIDE OF COMBEST CREEK

Commodities

Commodity Importance
Gold Primary
Lead Secondary
Silver Secondary
Copper Tertiary

Materials information

Materials Type of material
Galena Ore
Gold Ore
Quartz Gangue
Siderite Gangue

Analytical data

Result THREE CHANNEL SAMPLES HAD AN AVERAGE ASSAY OF 0.71 OZ/TON AU, 0.95 OZ/TON AG AND 4.6 % PB.

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock > Diorite
    Rock unit name Belt Series Intrusives
    Rock description Belt Series Intrusives
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Neoproterozoic
    Stratigraphic age (youngest) Neoproterozoic
  • Host or associated Host
    Rock type Sedimentary Rock > Clastic Sedimentary Rock > Argillite
    Rock unit name Prichard Formation
    Rock description Prichard Formation

Nearby scientific data

(1) -114.89543, 47.42849
ListMap

Economic information

Geologic structures

Type of structure Regional
Structure description Broad Folds In The Argillites Which Strike About N.
Type of structure Local
Structure description Fine Grained Dioritic Sill Is Exposed At The Adit Portal. Massive Fault, Six Ft Wide, Which Trends N 32 Deg W And Dips 72 Deg Sw.

Ore body information

  • General form POD/LENS
    Strike N 15 DEG W
    Dip 50 DEG SW

Controls for ore emplacement

  • Fault Zone. The Opening Which Allowed The Placement Of The Ore Body Could Have Been Formed By Two Possible Ground Movements, A Reverse Fault Or A Stike-Slip Fault.

Economic information about the deposit and operations

Development status Past Producer
Commodity type Metallic
Deposit size Small
Significant No
Discoverer Letterman
Year of first production 1911
Year of last production 1940

Mining district

District name Plains District

Land status

Ownership category Private

Ownership information

  • Type Owner-Operator
    Owner Montana Premier Mining Co.

Comments on the production information

  • SMALL AMOUNT OF AU-AG-PB ORE WAS PRODUCED FROM 1911-1940.

Comments on the workings information

  • PRINCIPAL DEVELOPMENT IS BY A 470 FT CROSSCUT ADIT WITH DRIFTS AT THE INTERSECTION OF THE FAULT ZONE. AS OF 1961 THE DRIFTS WERE ACCESSIBLE FOR A DISTANCE OF 280 FT. OTHER PROSPECT PITS AND SHALLOW WORKINGS WERE IN DISREPAIR IN 1961 .

Comments on development

  • MINE LAST OPERATED IN 1940 . 180 PATENTED AND 70 UNPATENTED CLAIMS.

Reference information

Bibliographic references

  • Analytical Data

    SRC.REF: CROWLEY, F. A., 1963 , MONTANA BUREAU OF MINES AND GEOLOGY BULL. 34 , P. 26

  • Deposit

    MONT. BUREAU OF MINES & GEOL. BULL. 33, 1963, P. 30

  • Deposit

    MONT. BUREAU OF MINES & GEOL. MEM. 31, 1950, P. 92

  • Deposit

    CROWLEY, F. A., 1963 , MINES AND MINERAL DEPOSITS (EXCEPT FUELS) SANDERS COUNTY, MONTANA: MONTANA BUREAU OF MINES AND GEOLOGY, BULL. 34 , PP. 25 - 26 .

  • Deposit

    GILBERT, F. C., 1935 , DIRECTORY OF MONTANA MINING PROPERTIES: MONTANA BUREAU OF MINES AND GEOLOGY MEM. 15 , P. 70 .

  • Production

    CROWLEY, F. A., 1963 : MONTANA BUREAU OF MINES AND GEOLOGY BULL. 34 , PP. 25 - 26 .

General comments

Subject category Comment text
Deposit ORE SHOOT IS PARTIALLY CONTAINED WITHIN A MASSIVE FAULT AND IS KNOWN AS THE FISHER VEIN. ORE SHOOT DIPS LESS STEEPLY THAN THE FAULT AND STRIKES ABOUT N 15 DEG W. ORE SHOOT BECOMES RICHER IN SULFIDES AS ONE GOES NW. GALENA IS MEDIUM GRAINED AND OCCURS AS PODS UP TO 1 FT LONG AND AS SMALL VEINLETS ABOUT 1 IN WIDE. CERUSSITE CRYSTALS FILL VUGS.
Deposit DEVELOPING (1962) ; INFO.SRC : 1 PUB LIT

Reporter information

Type Date Name Affiliation Comment
Reporter 01-MAR-1974 Unknown U.S. Geological Survey
Updater 01-APR-1979 Rojstaczer, Stuart A. U.S. Geological Survey

Beyond USGS

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

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