Unnamed (southwest ridge of Bush Mountain)

The Unnamed (southwest ridge of Bush Mountain) is a lead, nickel, molybdenum, copper, chromium, gold, and silver 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 (southwest ridge of Bush Mountain)

Commodity

Primary: Lead
Primary: Nickel
Primary: Molybdenum
Primary: Copper
Primary: Chromium
Primary: Gold
Primary: Silver

Location

State: Alaska
District: Ketchikan

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: Low-sulfide Au-quartz vein

Orebody

Not available

Structure

Not available

Alterations

Alteration Type: L
Alteration Text: Country rocks are propylitized and pyritic.

Rocks

Not available

Analytical Data

Not available

Materials

Ore: Pyrite
Ore: Chalcopyrite
Ore: Bornite
Ore: Pyrrhotite
Gangue: Albite
Gangue: Quartz
Gangue: Calcite

Comments

Comment (Geology): Age = Probably Late Cretaceous or younger.

Comment (Geology): Geologic Description = The country rocks in the area of this site include: undivided, metamorphosed Silurian and Ordovician volcanic, sedimentary, and intrusive rocks; Silurian trondhjemite; recrystallized, Upper Triassic sedimentary and volcanic rocks; and Upper Jurassic or Cretaceous flyschlike metasedimentary rocks and metavolcanic rocks (Berg, 1972 [I 684]; Berg and others, 1988; Karl, 1992). The rocks were regionally metamorphosed to greenschist-grade phyllite and semischist in Late Cretaceous time. The mineral occurrences consist of sheared, pyritic greenstone and microgabbro containing quartz and calcite veins (Karl, 1992, loc. 12a-d). Some of the quartz veins contain pyrite, pyrrhotite, chalcopyrite, and bornite. Some of the veins are cataclastic, and the microgabbro is propylitically altered to epidote, chlorite, quartz, calcite, and sericite. . A sample of greenstone containing calcite-pyrrhotite veins assayed 500 ppm Cr and 1000 ppm Ni. Samples of greenstone, a quartz-sulfide vein, and quartz-albite-pyrite breccia contained up to 3.25 ppm Au, 70 ppm Ag, 15000 ppm Cu, 500 ppm Pb, and 10 ppm Mo. A sample of microgabbro contained 500 ppm Cr and 200 ppm Ni; samples of greenstone and quartz breccia contained up to 3 ppm Ag and 700 ppm Cu (Karl, 1992, loc. 12a-d).

Comment (Reference): Primary Reference = Karl, 1992

Comment (Workings): Workings / Exploration = A sample of greenstone containing calcite-pyrrhotite veins assayed 500 ppm Cr and 1000 ppm Ni. Samples of greenstone, a quartz-sulfide vein, and quartz-albite-pyrite breccia contained up to 3.25 ppm Au, 70 ppm Ag, 15000 ppm Cu, 500 ppm Pb, and 10 ppm Mo. A sample of microgabbro contained 500 ppm Cr and 200 ppm Ni; samples of greenstone and quartz breccia contained up to 3 ppm Ag and 700 ppm Cu (Karl, 1992, loc. 12a-d).

Comment (Deposit): Model Name = Low-sulfide Au-quartz veins (Cox and Singer, 1986; model 36a)

References

Reference (Deposit): Karl, S.M., 1992, Map and table of mineral deposits on Annette Island, Alaska: U.S. Geological Survey Open-File Report 92-690, 57 p., 1 map, scale 1:63,360.

Reference (Deposit): Berg, H.C., Elliott, R.L., and Koch, R.D., 1988, Geologic map of the Ketchikan and Prince Rupert quadrangles, southeastern Alaska: U.S. Geological Survey Mineral Investigations Series Map MF-1807,27 p., scale 1:250,000.

Reference (Deposit): Berg, H.C., 1972, Geologic map of Annette Island, Alaska: U.S. Geological Survey Miscellaneous Geologic Investigations Map I-684, 8 p., 1 sheet, scale 1:63,360,

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