Geologic descriptionThe regional geology consists of deformed and metamorphosed Silurian or Devonian carbonate, clastic and volcanic clastic rocks that have been intruded by Upper Jurassic and Lower Cretaceous granitic and dioritic rocks (Brew and others, 1992). The Alaska Silver King Mine was discovered in 1938. It is in graywacke, and consists of small, discontinuous, sulfide-bearing quartz-calcite veins that strike ENE and dip nearly vertically. The veins varies from 4 to 10 inches thick and can be traced for up to 550 feet north of the mine. The sulfides consist of galena, pyrite, sphalerite, stibnite, and tetrahedrite (Clough and Redman, 1989). Samples contain up to 2,528 ppm silver, 2.3 percent lead, 7.5 percent zinc, and 1.5 percent antimony (Clough and Redman, 1989). The mine workings include an open cut 30 feet long and 10 feet deep. A 3000-foot aerial tram was installed between the beach and the mine shortly after discovery, and more than a ton of high-grade silver ore was mined and shipped to a smelter in Tacoma, Washington (Clough and Redman, 1989). |
