Unnamed (near West Fork of Post River)

The Unnamed (near West Fork of Post River) is a silver, zinc, and copper mine located in Alaska.

About the MRDS Data:

All mine locations were obtained from the USGS Mineral Resources Data System. The locations and other information in this database have not been verified for accuracy. It should be assumed that all mines are on private property.

Mine Info

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Site Name

Primary: Unnamed (near West Fork of Post River)

Commodity

Primary: Silver
Primary: Zinc
Primary: Copper
Secondary: Nickel

Location

State: Alaska
District: McGrath

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

Record Type: Site
Operation Category: Occurrence
Operation Type: Unknown
Years of Production:
Organization:
Significant:

Physiography

Not available

Mineral Deposit Model

Model Name: Bedded barite

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Sulfides oxidized to free sulfur.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Pyrite

Comments

Comment (Exploration): Status = Inactive

Comment (Workings): Workings / Exploration = The reporter sampled the occurrence in 1982. Two random chip-channel samples taken across the mineralized zone contained up to 1.37 percent zinc, 0.12 percent copper, 13.6 grams/tonne silver, and 196 ppm nickel.

Comment (Reference): Primary Reference = Bundtzen and others, 1988

Comment (Deposit): Other Comments = See other shale-hosted deposits in McGrath quadrangle such as MG049, MG029, MG051, MG071, MG064, and MG074.

Comment (Geology): Age = Inferred to be Lower Silurian, based on graptolite identifications (Bundtzen and others, 1988).

Comment (Deposit): Model Name = Sedimentary exhalitive lead-zinc(?) (Cox and Singer, 1986; model 31b).

Comment (Geology): Geologic Description = This unnamed occurrence is shale-hosted Ag-Cu-Zn mineralization in the Lower Ordovician-to-Lower Silurian Post River Formation, a unit of the Dillinger subterrane (Bundtzen and others, 1988). Graptolites of the Monograptus spiralus zone were found in the shale at the occurrence. A distinctive yellowish, sulfur bloom occurs in the mineralized zone, which is estimated to be about 2 meters thick. Disseminated pyrite was observed in one outcrop. Although isotopic data is lacking, Bundtzen, Harris, and Gilbert (1997) classified the occurrence as a sedimentary exhalitive lead-zinc deposit. Two random chip-channel samples collected across the zone contained up to 1.37 percent zinc, 0.12 percent copper, 13.6 grams/tonne silver, and 196 ppm nickel.

References

Reference (Deposit): Bundtzen, T.K., Kline, J.T., Smith, T.E., and Albanese, M.D., 1988, Geology of the McGrath A-2 quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Professional Report 91, 18 p., 1sheet, scale 1:63,360.

Reference (Deposit): Bundtzen, T.K., Harris, E.E., and Gilbert, W.G., 1997, Geologic Map of the eastern McGrath quadrangle, Alaska: Alaska Division of Geological and Geophysical Surveys Report of Investigations 97-14, 34 pages, one sheet, scale 1:125,000.

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