Twentymile River

The Twentymile River is a gold 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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MRDS mine locations are often very general, and in some cases are incorrect. Some mine remains have been covered or removed by modern industrial activity or by development of things like housing. The satellite view offers a quick glimpse as to whether the MRDS location corresponds to visible mine remains.

Site Name

Primary: Twentymile River

Commodity

Primary: Gold

Location

State: Alaska
District: Anchorage

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: Placer Au-PGE

Orebody

Not available

Structure

Not available

Alterations

Not available

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Gold

Comments

Comment (Reference): Primary Reference = Jansons and others, 1984

Comment (Workings): Workings / Exploration = Five alluvium samples from the upper portions of Twentymile River contained from a trace to 0.0073 oz Au/cubic yard (Jansons and others, 1984).

Comment (Geology): Geologic Description = Placer gold is disseminated in poorly- to moderately-washed glacial fluvial gravels along the upper portions of Twentymile Creek. Five alluvium samples from the upper portions of Twentymile River contained from a trace to 0.0073 oz Au/cubic yard (Jansons and others, 1984). Numerous large boulders are present (Hoekzema and Fechner, 1986). The bedrock in the region is Late Cretaceous metasedimentary rocks of the Valdez Group.

Comment (Deposit): Model Name = Placer Au (Cox and Singer, 1986; model 39a)

Comment (Production): Production Notes = No recorded production, however Hoekzema and Fechner (1986) state the mineral development potential is moderate for small mining operation. Pockets of higher grade material may occur within and adjacent to the river channel (Jansons and others, 1984).

Comment (Exploration): Status = Inactive

Comment (Geology): Age = Quaternary

References

Reference (Deposit): Hoekzema, R.B., and Fechner, S.A., 1986, Placer Gold sampling in and near the Chugach National Forest, Alaska: U.S. Bureau of Mines Information Circular 9091, 42 p.

Reference (Deposit): Jansons, Uldis, Hoekzema, R.B., Kurtak, J.M., and Fechner, S.A., 1984, Mineral occurrences in the Chugach National Forest, Southcentral Alaska: U.S. Bureau of Mines Open-File Report 5-84, 218 p., 2 sheets, scale 1:250,000.

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