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  3. Mineral Resource Data System (MRDS)

West Fork-Post River

Occurrence in Alaska, United States with commodities Silver, Copper, Zinc
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Sections on this page
  1. Identification information
  2. Geographic coordinates
  3. Site location context
  4. Geographic areas
  5. Commodities
  6. Materials information
  7. Mineral occurrence model information
  8. Host and associated rocks
  9. Nearby scientific data
  10. Economic information about the deposit and operations
  11. Mining district
  12. Links to other databases
  13. Bibliographic references
  14. General comments
  15. Reporter information

Geologic information

Identification information

Deposit ID 10002604
MRDS ID A015041
Record type Site
Current site name West Fork-Post River
Related records 10185370

Geographic coordinates

Geographic coordinates: -153.88281, 62.00947 (WGS84)
Relative position The West Fork-Post River occurrence is located on an east facing bluff of the west fork of Post River; it is at an elevation of approximately 4,000 feet (1,220 m) in the NE1/4 sec. 8, T. 22 N., R. 25 W., of the Seward Meridian. The occurrence, which corresponds to locality number 19 in Cobb (1972), is located to within 460 m.

Site location context

Political divisions (FIPS codes)

Bethel(Census area)

Alaska(state)

United States(country)

North America(continent)

Land(continent)

USGS map quadrangles

McGrath A-2(quadrangle 1:63,360 scale)

McGrath SE(quadrangle 1:100,000 scale)

McGrath(quadrangle 1:250,000 scale)

Hydrologic units (watersheds)

Upper Kuskokwim River(hydrologic accounting unit)

Southwest(hydrologic subregion)

Alaska(hydrologic region)

Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Copper Primary
Zinc Critical Secondary

Materials information

Materials Type of material
Chalcopyrite Ore
Pyrrhotite Ore
Sphalerite Ore

Mineral occurrence model information

Model code 85
USGS model code 22c
Deposit model name Polymetallic veins
Mark3 model number 46

Host and associated rocks

  • Host or associated Associated
    Rock type Plutonic Rock > Mafic Intrusive Rock
    Stratigraphic age (youngest) Pliocene
  • Host or associated Associated
    Rock type Plutonic Rock > Granitoid > Granite
  • Host or associated Host
    Rock type Plutonic Rock > Mafic Intrusive Rock

Nearby scientific data

(1) -153.88281, 62.00947
ListMap

Economic information

Comments on the geologic information

  • Geologic Description = The West Fork-Post River occurrence consists of small lenses and disseminations of pyrrhotite associated with a swarm of northwest-trending mafic dikes that cut argillite of the Early to Late Silurian Terra Cotta Mountains Sandstone, a unit of the Dillinger subterrane (Bundtzen and others, 1988; Bundtzen, Harris, and Gilbert, 1997). Samples collected by Reed and Elliott (1968, C 596) contained semi-massive pyrrhotite and minor chalcopyrite and sphalerite. Values from selected grab samples on the surface run up to 45.7 grams/tonne silver, 1.50 percent copper, and 0.07 percent zinc.

Economic information about the deposit and operations

Development status Occurrence
Commodity type Metallic

Comments on exploration

  • Status = Inactive

Mining district

District name McGrath

Comments on the workings information

  • Workings / Exploration = The West Fork-Post River was discovered by the late Bruce Reed during mineral investigations for the U.S. Geological Survey in the 1960s (Reed and Elliott, 1968, C 596). Values from selected grab samples collected by Reed and Elliott (1968, C 596) contain up to 45.7 grams/tonne silver, 1.50 percent copper, and 0.07 percent zinc.

Reference information

Comments on the references

  • Primary Reference = Reed and Elliott, 1968 (C 596)

General comments

Subject category Comment text
Deposit Model Name = Polymetallic vein (Cox and Singer, 1986; model 22c).
Deposit Other Comments = Similar to Veleska-South prospect (MG050) in McGrath B-2 quadrangle.

Reporter information

Type Date Name Affiliation Comment
Reporter 30-OCT-1998 T.K. Bundtzen Pacific Rim Geological Consulting

Beyond USGS

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

Maps centered on this site

Authoritative Alaska resources

These are landing pages for further research — the state agencies don't currently expose per-mine deep links.