The distribution and recovery of gold in the Golden Sunlight gold-silver telluride deposit, Montana, U.S.A.

Abstract

The gold balance in an ore deposit where the ore is treated by cyanide is the sum of the ‘visible gold’ that is amenable to cyanidation and ‘visible gold’ and the ‘invisible gold’, which are not amenable to cyanidation. Petrographic analyses, electron and ion microprobe as well as scanning electron microscope studies of ore from the Golden Sunlight deposit, Montana, suggest that periods of relatively poor gold recoveries are primarily due to the presence of inclusions, <25 µm in size, of native gold, petzite, calaverite, buckhornite and krennerite. These are encapsulated in cyanide insoluble grains of pyrite, chalcopyrite and tennantite and are present in the tailings. This contribution probably accounts for 3–25% of the unrecoverable gold processed during the life of the mine. Minor amounts (6–7%) of ‘invisible gold’, as indicated by ion microprobe studies and the presence of up to 5% ‘visible gold’ in buckhornite, which is rare in nature, appears to account for the remainder of the gold budget.

Speciation of noble metals and conditions of their concentration in massive sulfide ores of the Urals

“…These authors have established an inverse correlation between the Au content in pyrite (from results of fire assay) and the size of gold grains. A similar result has been obtained with the more local method of secondary ion mass spectroscopy (SIMS) (Spry and Thieben, 2000). Thereby, the maximum concentration of invisible gold in pyrite was estimated at 1.18 ppm.…”

Montana Mineral Locality Index

“…NW of Whitehall; in 1953 Ray Davenport staked the Mona claim and worked it with his son for about a year. Afterward, Marcus Pruett of Butte took up the claim: albite, allanite (crystals to 10 cm), quartz, scheelite (tan crystals to 2 cm), schorl, titanite* (brown crystals to 13 cm) (Toland 1973 (Spry and Thieben 2000).…”

Process mineralogy of gold: Gold from telluride-bearing ores

“…Gold mineralization is hosted primarily within a hydrothermal breccia pipe and is spatially related to a sub-alkalic-to-alkalic intrusive system that cross-cuts sedimentary rocks. 6 During cyanide treatment of the ore, recoveries have ranged from 65% to 85%. The ore is ground to 37 µm for main leach and as fi ne as 25 µm for pyrite leach.…”

“…Precious metal tellurides are notoriously refractory phases. [2][3][4][5][6] GOLD-SILVER TELLURIDE DEPOSITS…”