The Golden Sunlight veins are in a north-trending vein zone on the east side of the mountain, near a basin-margin fault of similar trend. Numerous small latite porphyry bodies in and near the Golden Sunlight mine are hydrothermally altered and mineralized and are the host for about 25 percent of the disseminated ore. About half of the ore body is in a breccia pipe that consists partly of fragmented argillite and partly of fragmented latite porphyry.

Quartz veins in north-trending zone cutting argillite and calcareous argillite of the Proterozoic Greyson Formation and latite of probably Late Cretaceous age. Veins are associated with a breccia pipe that hosts part of a large disseminated gold deposit. Gold is mostly free and associated with pyrite.

GSM’s (Golden Sunlight Mine) underground mine, 2BUG (Stage 2B, underground), has implemented vein mining as well as sub-level longhole open stoping for recovering underground ore. Sublevel open stoping is a mining method involving sublevel drifts located above the main haulage road (Hamrin, 2001). The stope drilling is conducted from the sublevel drifts, where ore is blasted in separate portions toward an open face. Once the ore is blasted, gravity causes the ore to pile at the bottom level at the drawpoints located along the haulage route where the ore is collected and transported to the mill for processing.

Stopes at GSM can leave openings as large as 30 m (100 ft.) wide, 60 m (200 ft.) tall, and 60 m (200 ft.) long.

The ore treatment plant uses conventional carbon-in-pulp technology as well as Sand Tailing Retreatment (STR), designed to recover gold that would otherwise be lost in the process.

Gold is extracted from ore at GSM using a variety of physical and chemical processes. Ore is first crushed and ground, then gold is extracted using an agitated leach cyanide process.

Initial processing includes a crushing circuit consisting of primary, secondary, and tertiary crushing.

Crushing involves reducing rock particle size using gyratory and cone crushers to minus ¾ inch. Wet grinding in rod and ball mills further reduces rock size to 65 percent passing 100 mesh (150 microns or ~ 0.0058 inch). Grind circuit product is thickened with thickener and overflow is pumped to Carbon Columns where gold is adsorbed onto carbon.

Ground ore slurry is mixed with sodium cyanide, lime, and compressed air in eleven 400,000 gallon leach tanks equipped with agitators to k ........