Threeman Mining Co.

The Threeman Mining Co. is a copper and zinc 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: Threeman Mining Co.

Commodity

Primary: Copper
Primary: Zinc
Secondary: Silver

Location

State: Alaska
District: Copper River

Land Status

Not available

Holdings

Not available

Workings

Not available

Ownership

Not available

Production

Not available

Deposit

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

Physiography

Not available

Mineral Deposit Model

Model Name: Massive sulfide, Cyprus

Orebody

Not available

Structure

Not available

Alterations

Not available

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Pyrrhotite
Ore: Chalcopyrite

Comments

Comment (Deposit): Model Name = Cyprus massive sulfide (Cox and Singer, 1986; model 24a)

Comment (Deposit): Other Comments = Nelson and others (1985) interpret the country rocks as accreted ocean crust. Crowe and others (1992; 1993) and Sainsbury (1993) discuss the genesis of the volcanogenic massive sulfide deposits in this area.. Chugach Alaska Corporation, Anchorage, Alaska has control of these lands.

Comment (Exploration): Status = Inactive

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

Comment (Geology): Geologic Description = The country rocks at this prospect are mafic volcanic rocks and sedimentary rocks of the Tertiary Orca Group (Nelson and others, 1985). The deposit consists of up to foot-thick lenses of chalcopyrite and pyrrhotite.in two-foot- to 15-foot-wide shear zones. Three chip samples contained 200 ppm to 1% Cu, 145 ppm to 0.89% Zn, and <0.2 to 6 ppm Ag; a grab sample from the dump contained 4.9% Cu, 0.49% Zn, and 50 ppm Ag (Jansons and others, 1984).

Comment (Geology): Age = Probably Tertiary based on the age of the host rocks.

Comment (Workings): Workings / Exploration = One 41-foot-long adit. Three chip samples contained 200 ppm to 1% Cu, 145 ppm to 0.89% Zn, and <0.2 to 6 ppm Ag; a grab sample from the dump contained 4.9% Cu, 0.49% Zn, and 50 ppm Ag (Jansons and others, 1984).

References

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.

Reference (Deposit): Crowe, D.E., Nelson, S.W., Brown, P.E., Shanks III, W.C., and Valley, J.W., 1993, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound, south-central Alaska-A reply: Economic Geology, v. 88, p. 1285-1288.

Reference (Deposit): Sainsbury, C.L., 1993, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound, south-central Alaska, A discussion: Economic Geology, v. 88, p. 1284-1285.

Reference (Deposit): Crowe, D.E., Nelson, S.W., Brown, P.E., Shanks III, W.C., and Valley, J.W., 1992, Geology and geochemistry of volcanogenic massive sulfide deposits and related igneous rocks, Prince William Sound, south-central Alaska: Economic Geology, v. 87, p. 1722-1746.

Reference (Deposit): Nelson, S.W., Dumoulin, J. A., and Miller, M.L., 1985, Geologic map of the Chugach National Forest, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map MF-1645-B, 16 p., 1 sheet, scale 1:250,000.

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