Central Idaho bismuth-bearing veins

Region West, Northwest
Mineral systems
Deposit types
Critical minerals
Other minerals

Information leading to the delineation of this focus area

Basis for focus area Multi-part focus area of bismuth-bearing polymetallic Pb-Ag and Au-Ag veins, replacements, and mineralized shear zones. Main area includes Washington Basin.
Identified resources Possible identified resources of bismuth in gold and silver mineralization; historical production of gold, lead, and silver.
Production Unknown.
Status Past mining.
Estimated resources Inferred submarginal Au-Ag veins (Empire and Washington) estimated at about 5,000,000 tons (4,500,000 tonnes); semi-quantitative analyses assays of vary from 0. 05 to 0.07% Bi. An additional l,600,000 tons (1,450,000 tonnes) of submarginal material from the nearby Last Resort vein may average 0.30% Bi (Tschanz and Kiilsgaard, 1986).
Geologic maps Tschanz and others (1986, plate 1), scale 1:62,500; Rember and Bennett (1979), scale 1:250,000.
Geophysical data Inadequate aeromagnetic and aeroradiometric coverage.
Favorable rocks and structures In the Washington basin, polymetallic vein deposits near the Cretaceous granodiorite-Paleozoic contact and in fold-hinge parallel fractures are interpreted to be the result of late-stage hydrothermal fluid circulation associated with intrusion of Cretaceous granodiorite (Mahoney, 1995).
Deposits Last Resort vein (MRDS dep_id: 10070967), Reconstruction vein (MRDS dep_id: 10071213), Yacomella veins (MRDS dep_id: 10071212), Empire vein (Washington Basin deposit) (MRDS dep_id: 10096298).
Evidence from mineral occurrences MRDS.
Geochemical evidence Anomalous Bi in rocks, streambed sediments, and soils in the Washington Basin area. Minerals: bismuthinite, native bismuth, bismuth tellurides, tetradymite, joséite (Tschanz and Kiilsgaard, 1986).
Geophysical evidence Unknown.
Evidence from other sources Unknown.
Comments Claims in the Washington Basin were originally located for Au, but most production was in Pb-Ag ores and some interest has been shown in the scheelite and telluride occurrences (Tschanz and Kiilsgaard, 1986).
Cover thickness and description Exposed at the surface.
Authors Reed S. Lewis, Virginia S. Gillerman, Christopher A. Tate, Jane M. Hammarstrom.
New data needs Geophysics.
Geologic mapping and modeling needs None requested at this time.
Geophysical survey and modeling needs High-resolution, Rank 1 aeromagnetic and aeroradiometric surveys.
Digital elevation data needs Lidar incomplete.