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West Fork

Prospect in Alaska, United States with commodities Silver, Lead, Zinc, Copper
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Geologic information

Identification information

Deposit ID 10307551
Record type Site
Current site name West Fork

Geographic coordinates

Geographic coordinates: -147.49283, 63.80964 (WGS84)
Relative position The West Fork prospect is at an elevation of about 4,500 feet, in the south wall of an east-flowing branch of West Fork Little Delta River. The map site is about 4 miles southwest of the junction of Forgotten Creek, in the NW1/4 of sec. 11, T. 13 S., R. 1 E., of the Fairbanks Meridian. The location is accurate to within 0.5 mile.
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Geographic areas

Country State
United States Alaska

Commodities

Commodity Importance
Silver Primary
Lead Primary
Zinc Primary
Copper Secondary

Materials information

Materials Type of material
Galena Ore
Pyrite Ore
Sphalerite Ore
Quartz Gangue
Sericite Gangue

Alteration

  • (Local) Quartz and sericite.

Mineral occurrence model information

Model code 184
USGS model code 28a
Deposit model name Massive sulfide, kuroko
Mark3 model number 93

Host and associated rocks

  • Host or associated Host
    Stratigraphic age (youngest) Late Devonian

Nearby scientific data

(1) -147.49283, 63.80964
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Comments on the geologic information

  • Geologic Description = The country rocks at the West Fork prospect are Upper Devonian(?) felsic metavolcanic rocks consisting of schist and phyllite, locally containing relict phenocrysts of quartz, orthoclase, and plagioclase (Wilson and others, 1998). The deposit consists of stratiform layers of massive pyrite, galena, and sphalerite, accompanied by quartz and sericite. Samples of a 20-30-centimeter-wide massive-sulfide horizon contained 3.68% lead, 4.05% zinc, 131 grams of silver per tonne and 0.38 grams of gold per tonne (www.grayd.com, 1999).
  • Age = Mineralization was probably syngenetic with the Upper Devonian host rocks.

Economic information

Economic information about the deposit and operations

Development status Prospect

Comments on exploration

  • Status = Active

Mining district

District name Bonnifield

Comments on the workings information

  • Workings / Exploration = The prospect has been explored by surface sampling, geophysical work, and one drill hole (Inmet Mining, personal communication, 1999). Samples of a 20-30-centimeter-wide massive-sulfide horizon contained 3.68% lead, 4.05% zinc, 131 grams of silver per tonne and 0.38 grams of gold per tonne (www.grayd.com, 1999).

Reference information

Links to other databases

Agency Database name Acronym Record ID Notes
USGS Alaska Resource Data File ARDF HE120

Bibliographic references

  • Deposit

    Wilson, F.H., Dover, J.H., Bradley, D.C., Weber, F.R., Bundtzen, T.K., and Haeussler, P.J., 1998, Geologic map of central (interior) Alaska: U.S. Geological Survey Open-File Report 98-133, 17 p., 2 sheetsm, scale 1:500,000.

  • Deposit

    www.grayd.com, 1999.

Comments on the references

  • Primary Reference = www.grayd.com, 1999

General comments

Subject category Comment text
Deposit Model Name = Kuroko massive sulfide (Cox and Singer, 1986; model 28a)

Reporter information

Type Date Name Affiliation Comment
Reporter 07-APR-00 N. Van Wyck Stevens Exploration Management Corporation