|Quadrangle map, 1:250,000-scale||JU|
|Quadrangle map, 1:63,360-scale||A-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Alaska Empire mine is at an elevation of approximately 1,000 feet on Mansfield Peninsula, 1.2 miles northwest of Hawk Inlet, 3.5 miles southeast of Mount Robert Barron, and 3 miles west of Young Bay. The site is at the mine symbol on the 1:63,360-scale topographic map, in the NW1/4SE1/4 section 33, T. 42 S., R. 65 E. of the Copper River Meridian. The location is accurate.|
The deposit consists of 10 quartz-calcite veins, 2.5 feet to 50 feet thick, that strike north, dip steeply east, and can be traced for over 500 feet. The host rocks are greenschist, quartz-mica schist, and black graphitic phyllite (Townsend, 1941). One vein has been traced for over 2000 feet (Buddington, 1926). The hanging wall of the veins contains up to 5 percent pyrite. Some of the quartz is white, massive, and barren, and some is bluish and friable. The bluish veins contain pyrite, galena, sphalerite, chalcopyrite, and sparse pyrrhotite. All production has come from the Williams vein, which is up to 50 feet thick and has a vertical extent of at least 400 feet (Wells and others, 1986). The deposit was discovered before 1900 and has produced small amounts of gold intermittently since that time (Cobb, 1978 [OFR 78-374]). From 1931 to 1937, the Williams vein produced 17,767 tons of ore from a glory hole (Townsend, 1941). Other workings include a 353-foot tunnel, a 48-foot winze, several short crosscuts, open cuts, and surface trenches (Buddington, 1926).The rocks in the general area are mainly Ordovician and Devonian to Triassic, clastic units, mafic-intermediate volcanic rocks, and subordinate limestone. The bedded rocks are intruded and locally metamorphosed by Cretaceous granodiorite (Gehrels and Berg, 1994).
|Geologic map unit||(-134.788888172826, 58.1837642970376)|
|Workings or exploration||Discovered before 1900, workings include a glory hole, a 353-foot tunnel, a 48-foot winze, several short crosscuts, open cuts, and surface trenches.|
|Indication of production||Yes; small|
|Production notes||From 1931 to 1937, the Williams vein produced 17,767 tons of ore from a glory hole (Townsend, 1941).|
Buddington, A.F., 1926, Mineral investigations in southeastern Alaska: U.S. Geological Survey Bulletin 783, p. 41-62.
Cobb, E.H., 1978, Summary of references to mineral occurrences (other than mineral fuels and construction materials) in the Juneau quadrangle, Alaska: U.S. Geological Survey Open-File Report 78-374, 155 p.
Gehrels, G.E., and Berg, H.C., 1994, Geology of southeastern Alaska, in Plafker, George, and Berg, H. C., eds., The geology of Alaska: Geological Society of America, DNAG, The geology of North America, Vol. G-1, p. 451-467.
Townsend, H.H., 1941, Report on Alaska Empire Mine, Hawk Inlet, Admiralty Island, Alaska: Alaska Division of Geological and Geophysical Surveys Miscellaneous Report 112-11, 27 p.
|Reporters||J.C. Barnett and L.D. Miller (Juneau, Alaska )|
|Last report date||12/15/2001|