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Liberty

Mine, Probably inactive

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Commodities and mineralogy

Main commodities Au
Other commodities As; Cu; Hg
Ore minerals arsenopyrite; chalcopyrite; pyrite

Geographic location

Quadrangle map, 1:250,000-scale SI
Quadrangle map, 1:63,360-scale A-4
Latitude 57.0082
Longitude -135.1733
Nearby scientific data Find additional scientific data near this location
Location and accuracy Bittenbender and others (1999, location. P-121) and the US Bureau of Land Management (2002, MAS no. 0021140055) locate the Liberty prospect at sea level in the west side of Silver Bay, about 0.4 mile west of triangulation station Ranus. It is in the SW1/4SW1/4 sec. 13, T. 56 S., R. 64 E., of the Copper River Meridian. Cobb (1972; 1978, location 59) locates it at an elevation of about 500 feet in the NW1/4 sec. 24, of the same township and range, but Bittenbender and others actually mapped the workings. The location is accurate.

Geologic setting

Geologic description

The host rock at the Liberty Mine is part of the Jurassic and Cretaceous, Sitka Graywacke which consists mainly of graywacke and argillite (Loney and others, 1975).
The mine was first mentioned by Becker (1897) when the property was in operation. He described the deposit as a series of imbricate quartz lenses up to 7 feet thick, along a fault. The vein contained pyrite, chalcopyrite, and arsenopyrite. A mill recovered about $2.50 in gold per ton of feed stock and about half of the gold was probably passed into the tailings. Some mill test recovered as much as $5 per ton, i.e., the ore contained up to about 0.5 ounce of gold per ton. The amount of gold that was produced was not given. There is no indication of any significant amount of work on the property after 1905 (Wright and Wright, 1905; Wright, 1907; Knopf, 1912).
The deposit was mapped by Bittenbender and others (1999) who located two adits, one 30 feet long and the other 300 feet long. In the longer adit, discontinuous quartz lenses, often brecciated, are exposed along a fault zone for about 100 feet. The quartz lenses are up to 5 feet thick. The quartz contains minor sulfides, mainly pyrite. The best sample they collected contained 60 parts per billion gold, across 3 feet. Samples contained up to 398 parts per million (ppm) arsenic and two samples contained more than 2 ppm mercury. The same vein structure is exposed in the shorter and higher adit.
Geologic map unit (-135.175064152983, 57.0078364143261)
Mineral deposit model Low-sulfide gold-quartz vein (Cox and Singer, 1986; model 36a).
Mineral deposit model number 36a
Age of mineralization Jurassic or younger based on the age of the host rock.

Production and reserves

Workings or exploration The property was active before 1900, but probably not in any substantial way since.
Indication of production Yes; small
Production notes Becker (1897) implies that some gold was produced.

References

MRDS Number A013305

References

Bittenbender, P., Still, J.C., Maas, K., and McDonald, M., Jr., 1999, Mineral resources of the Chichagof and Baranof Islands area, southeast Alaska: Bureau of Land Management, BLM-Alaska Technical Report 19, 222 p.
Knopf, Adolph, 1912, The Sitka mining district, Alaska: U.S. Geological Survey Bulletin 504, 32 p.
Loney, R.A., Brew, D.A., Muffler, L.J.P., and Pomeroy, J.S., 1975, Reconnaissance geology of Chichagof, Baranof, and Kruzof Islands, southeastern Alaska: U.S. Geological Survey Professional Paper 792, 105 p.
U.S. Bureau of Land Management, 2002, Alaska mineral locations database report (Sitka quadrangle), July 2, 2002, 205 p. [http://imcg.wr.usgs.gov/dem.html]
Wright, C.W., 1907, Lode mining in southeastern Alaska, in Brooks, A.H., and others, Report on progress of investigations of mineral resources of Alaska in 1906: U.S. Geological Survey Bulletin 314, p. 47-72.
Wright, F.E., and Wright, C.W., 1905, Economic developments in southeastern Alaska, in Brooks, A.H., Report on Progress of Investigations of Mineral Resources of Alaska in 1904: U.S. Geological Survey Bulletin 259, p. 47-68.
Reporters Donald Grybeck (U.S. Geological Survey)
Last report date 5/5/2005