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Midway

Occurrence, Inactive

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Commodities and mineralogy

Main commodities Ag; Au
Other commodities Hg; Zn
Ore minerals pyrite
Gangue minerals chalcedony; jasper; zeolite

Geographic location

Quadrangle map, 1:250,000-scale PM
Quadrangle map, 1:63,360-scale A-3
Latitude 55.225
Longitude -160.691
Nearby scientific data Find additional scientific data near this location
Location and accuracy This occurrence is located on Unga Island approximately 2 miles northeast of the head of Acheredin Bay and 4,000 feet north of Acheredin Lake (Wilson and others, 1988, locality 32). The map site is at an elevation of 1,100 feet, near the south end of the boundary between secs. 20 and 21, T. 57 S., R. 75 W., of the Seward Meridian. The location is accurate to within 2,500 feet.

Geologic setting

Geologic description

This occurrence consists of several knobs of andesite breccia in an area 100 by 1,000 feet. The breccias contain pyrite, chalcedony, jasper, and zeolite. Samples of the breccia contained as much as 0.02 ppm gold, 15 ppm silver, 720 ppm zinc, 510 ppm arsenic, and 5 ppm mercury (Peterson and others, 1982). The andesite is part of the late Eocene to early Oligocene Popof volcanic rocks (Wilson and others, 1995).
Geologic map unit (-160.693056761496, 55.2241648699568)
Mineral deposit model Epithermal gold vein
Age of mineralization Eocene or younger.

Production and reserves

Workings or exploration UNC Teton Exploration Drilling Company sampled the occurrence in 1982. Samples contained as much as 0.02 ppm gold, 15 ppm silver, 720 ppm zinc, 510 ppm arsenic, and 5 ppm mercury.
Indication of production None

Additional comments

The site is located on land patented by, or interim-conveyed to, the Aleut Corporation.

References

References

Peterson, R.J., Lemmers, J., Handverger, P., Gallagher, J., Pilcher, R., East, J., Macleod, T., Bartels. E., 1982, Geology and precious metals potential Unga, Popof, and Korovin Islands, Shumagin Group, Aleutian Chain, Alaska: UNC Teton Exploration Drilling Company report, 127 p., 5 map sheets, various scales. (Report held by the Aleut Corporation, Anchorage, Alaska.)
Wilson, F.H., Detterman, R.L., Miller, J. W., and Case, J.E., 1995, Geologic map of the Port Moller, Stepovak Bay, and Simeonof Island quadrangles, Alaska: U.S. Geological Survey Miscellaneous Investigation Series Map I-2272, 1 sheet, scale 1:250,000.
Wilson, F.H., White, W.H., and DuBois, G.D., 1988, Brief descriptions of mines, prospects, and mineral occurrences in the Port Moller and Stepovak Bay quadrangles, Alaska Peninsula: U.S. Geological Survey Open-File Report 88-666, 128 p., 1 plate, scale 1:250,000.
Reporters S.H. Pilcher
Last report date 1/12/2001