Cobalt Signatures of Gold-Bearing Pyrite Kensington Gold Mine, SE Alaska

Abstract

The Kensington mine is located about 45 miles northwest of Juneau and is expected to produce 125,000 ounces of gold annually. The Kensington ore body is an early Tertiary vein system hosted in a weakly metamorphosed mid-Cretaceous pluton. The traditionally known veins (quartz-Au veins) are structurally controlled by prominent shear zones in the Jualin Pluton and are primarily quartz >> calcite, with 10-20% pyrite. The pyrite contains metallic gold, chalcopyrite, and telluride minerals, either as inclusions, along grain boundaries, or fracture fill (fig. 3a – 3c). The quartz-Au veins have varying concentrations of chalcopyrite.