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Investigations of Gossans of Hot Springs Dome, Near Manley Hot Springs, Alaska.
For Reference Only At Bureau Libraries :28 pages
Prominent gossans on the summit of Hot Springs Dome were investigated during 1953-54 to determine whether commercially valuable metal sulfides were below the zone of oxidation. The gossan-capped zones are 100 to 500 feet long and 20 to 50 feet wide in metamorphosed sedimentary rocks near their contact with a large body of granitic intrusives. The gossans had been explored superficially and two claims on the strongest gossans had been patented. Various government geologists and engineers reported the presence of small amounts of lead, zinc, copper, and cobalt sulfides or oxides, but in general the pits and adits had disclosed iron and manganese oxides only. The Bureau of Mines drilled eight diamond holes in 1954 that varied in length from 243 to 515 feet. The objective was to penetrate to the zone of primary sulfides but oxidation was practically complete to a vertical depth of slightly more than 400 feet, which was the limit of the equipment; however, a small amount of galena in relatively unfractured rock was intersected by one hole. Most of the drill hole intersections were in strongly brecciated rock that was traversed by numerous seams of limonite, goethite, or siderite; some of these seams were several feet wide.
For Reference Only At Bureau Libraries
Page last reviewed: March 11, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division