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Lithophile Metal, Ree-y-nb Deposits on Southern Prince of Wales Island, Alaska.
Metall Soc 1988 :139-157
Bureau of Mines investigations of a 55-km-long trend of intrusive complexes on Southern Prince of Wales Island identified significant resources of Nb, y, ree, u, zr, and a host of potential byproduct metals. The northwesterly trend comprises multiphased sodic alkaline and peralkaline diorite, monzonite, syenite, and riebeckite granite. Three significant deposit types recognized, two of which contain most of the lithophile metals, are: (1) pegmatite dikes and/or vein dikes that zone laterally from the intrusions and (2) concentrically zoned pegmatites. A third, epigenetic replacement- type mineralization contains much of the u resource. This report summarizes the deposit evaluations, characterizes the mineralization, and estimates the resources. To date a total of 40.7 million tons of mineralized materials is estimated as indicated or inferred. Most of the y2o3 plus reo is at a grade exceeding 0.5 pct, and half of the Nb2o5 exceeds 0.125 pct. Tonnage estimates would likely be substantially increased with additional exploration. Mineralogy is generally fine-grained and complex, and consists of more than a dozen principal ree-y-nb-u-th-zr phases, the sum of which may compose up to half of the rock. Approximately half of the ree-y content comprises the heavy yttrium subgroup, which is uncommon compared to deposits elsewhere. Alaskan deposits are likely subeconomic at today's metal prices and consumption levels, but recent technological advances suggest future demand may increase.
Metall. Soc., 1988, PP. 139-157