|Quadrangle map, 1:250,000-scale||SV|
|Quadrangle map, 1:63,360-scale||C-2|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||The Nukalaska mine is on a precipitous north-facing slope below peak 2560 in the southwest part of the Seldovia C-2 quadrangle. The mine's camp was located on Sunny Cove, an embayment on the west arm of Nuka Bay. From the camp, a road was driven 1 1/4 miles to the mill site at an approximate elevation of 600 feet. The mill site was the terminus of an aerial tramway which rose 1,800 feet to the mine's portal about 235 feet north and 200 feet below the discovery outcrop. This Cobb's (1972, MF-397) location 17 and Richter's location 1. This location is accurate to within 300 feet.|
The host rocks of the mine are slate and graywacke of the Cretaceous Valdez Group that have been cut by quartz diorite dikes of Tertiary age (Richter, 1970). The deposit consists of a 10- to 18-inch-thick banded quartz vein that occurs along the footwall of a 12-foot-thick quartz diorite dike. The vein is younger than the dike; low-grade veinlets that divert into the dike are common. The vein strikes almost due east at a right angle to the graywacke country rock and dips 80S. The ore consists of somewhat banded quartz with free gold, arsenopyrite, pyrite, galena, and chalcopyrite. Microscopic examination by Yewell (Capp,1938) also identified tetrahedrite, chalcocite, and covellite. The gold appears to be localized within high-grade shoots within the vein.From the top of the tramway the main haulage drift was driven 235 feet to intersect the vein. Two drifts were driven both east and west along the vein. The east drift was driven 200 feet but no significant mineralization was encountered. All the production came from the west drift. In 1936, the west stope was 140 feet long and 80 feet high along the 12- to 18-inch-wide vein. Concentrates from this stope carried 21 to 51 ounces of gold per ton; even though two-thirds of the mill feed was wall rock (Capps, 1938).
|Geologic map unit||(-150.669091547777, 59.5084128606596)|
|Mineral deposit model||Low-sulfide, Au-quartz vein (Cox and Singer, 1986; model 36a)|
|Mineral deposit model number||36a|
|Age of mineralization||Tertiary; Boden and others (1991) report other veins in the district are about 55 m.y. old.|
|Alteration of deposit||None reported although Borden and others (1991) report other veins in the Nuka Bay district show carbonization, sulfidization, sericitization, and silicification of the wall rock adjacent to the veins.|
|Workings or exploration||The mine was discovered in 1926 and developed in 1934-35. It produced from 1935 to 1940. In 1936, the west stope was 140 feet long and 80 feet high along the 12- to 18-inch-wide vein. Concentrates from this stope carried 21 to 51 ounces of gold per ton; even though two-thirds of the mill feed was wall rock (Capps, 1938). A fire in 1938 and snow slides in 1939 hampered mining. World War II closed the mine in 1942 and an attempt to reopen the mine after the war failed (Richter, 1970).|
|Indication of production||Yes; small|
|Reserve estimates||None reported.|
|Production notes||The gold occurred in very high-grade shoots. Ore mined in 1936 yielded $100 per ton ($35 per ounce gold) even though two-thirds of the mill feed was country rock (Capps, 1938, p.27-29). The total production for this mine is unknown.|
Additional commentsThis mine is within Kenai Fjords National Park; the area is closed to mineral entry.
Berg, H.C., and Cobb, E.H., 1967, Metalliferous lode deposits of Alaska: U.S. Geological Survey Bulletin 1246, 254 p.
Borden, J.C., Goldfarb, R.J., Gent, C.A., Burruss, R.C., and Roushey, B.H., 1992 Geochemistry of lode-gold deposits, Nuka Bay district, southern Kenai Peninsula, in Bradley, D.C., and Dusel-Bacon, Cynthia, eds, Geologic studies in Alaska by the U.S. Geological Survey, 1991: U.S. Geological Survey Bulletin 2041, p. 13-21.
Capps, S.R., 1938, Lode mining in the Nuka Bay district, in Smith, P.S., and other, Mineral industry of Alaska in 1936: U.S. Geological Survey Bulletin 897-A, p. 25-32.
Cobb, E.H., 1979, Summary of references to mineral occurrences (other than minerals fuels and construction materials) in the Seldovia quadrangle, Alaska: U.S. Geological Survey Open-file Report 80-87, 47 p.
MacKevett, E.M., Jr., and Holloway, C.D., 1977, Map showing metalliferous and selected non-metalliferous mineral deposits in the eastern part of southern Alaska: U.S. Geological Survey Open-File Report 77-169-A, 99 p., 1 sheet, scale 1:1,000,000.
Richter, D.H., 1970, Geology and lode-gold deposits of the Nuka Bay area, Kenai Peninsula, Alaska: U.S. Geological Survey Professional Paper 625-B, p. Bl-B16.
Smith, P.S., 1939, Mineral industry of Alaska in 1937: U.S. Geological Survey Bulletin 910-A, p. 1-113.
|Reporters||Jeff A. Huber (Anchorage)|
|Last report date||2/2/1999|