Platinum-group metals (PGM) are reported in dredge, sluice box, and pan concentrates and in placer gold bullion from more than 40 onshore, coastal, and offshore sites in Alaska. Among these are the Salmon River placers, where the Goodnews Bay Mining Company and other operators produced about 650,000 tr oz of PGM and about 10,000 tr oz of gold. The offshore potential at Goodnews Bay and nearby Red Mountain, where PGM mineral grains and submarine source rock have been identified, is yet undefined. Offshore targets at Lituya Bay and Kodiak Island, where PGM have been identified in beach sand concentrates, are unexplored. More typically, PGM occur in trace to minor amounts in certain onshore placer gold concentrates, but the amount of PGM recovered in this manner is generally unpublished. Such occurrences range from reports of "small amounts of platinum in placer gold concentrates" to Miller Gulch in the Chistochina Placer Gold District, where recovered precious metals have included 1 to 2 pct PGM since mining began in 1900. In addition to the offshore resources at Goodnews Bay and elsewhere along the Alaska coast, placer PGM resources that contain little gold might exist in onshore areas that are proximal to Mafic and Ultramafic bedrock sources. Foremost among PGM placer targets are areas marginal to, or underlain by, "concentrically" zoned Alaskan-type Ultramafic complexes like those that are the source rocks for productive PGM placers at Goodnews Bay, Alaska, and in the U.S.S.R. and British Columbia.
Paper in Proc. of the 10th Alaskan Placer Mining Conf., Fairbanks, Alaska, Mar. 24, 1988, PP. 76-80