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Laboratory evaluation of some factors in cyaniding gold placers.
Nichols-IL; Salisbury-HB; Shibler-BK
Salt Lake City, UT: U.S. Department of the Interior, Bureau of Mines, RI 7559, 1971 Jan; :1-12
The in-place cyanidation leaching of gold from placer deposits is a potential method for treating gravels too deeply buried and too low in gold content to be processed economically by conventional dredging methods. Laboratory experiments were made to evaluate those placer cyanidation factors adaptable to small-scale studies. The variables investigated included gold particle size and location in sand beds, cyanide solution flow rate, and cyanide solution strength as factors affecting gold solubility rates. The solution flow rate, in turn, was influenced by variables such as bed slope, solution head pressure, and sand size, and the effects of these factors were studied. Free gold, minus 150-mesh and finer in size, is rapidly dissolved by dilute cyanide solutions from mixtures of gold and silica and prepared to simulate placer deposits. About 94 percent of minus 325-mesh free gold was extracted in 5 hours from silica sand mixtures, and 94 percent extraction of minus 150-mesh gold was obtained in 21 hours with 0.1 percent NaCn solutions. Moving solutions were almost twice as effective in leaching free gold from silica sand mixtures than stagnant solutions.
Mineral-deposits; Mineral-processing; Laboratory-testing; Mining-industry; Metal-mining; Cyanide-compounds
IH; Report of Investigations
NTIS Accession No.
Salt Lake City, UT: U.S. Department of the Interior, Bureau of Mines, RI 7559
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division