Abstract
The Bureau of Mines conducted laboratory batch beneficiation tests on samples from four potential platinum resources in southeastern Alaska to concentrate platinum and other precious metals. This investigation was done as part of the mission of the Bureau to insure an adequate supply of minerals to meet the nation's needs. Petrographic studies and beneficiation methods including gravity concentration, froth flotation, and magnetic separation were used to determine mineral association and to attempt to concentrate the platinum values with a primary mineral value such as chromite, copper sulfide, or magnetite. A high-graded sample from the salt chuck copper sulfide deposit yielded the best platinum-group metal concentrate; the maximum grade attained was 0.04 Oz pt and 1.5 Oz pd per ton of high-grade copper sulfide concentrate. The other samples yielded low-grade mineral concentrates with low platinum-group values, and/or the platinum-group metals did not concentrate with the primary mineral value.
