The main rock types in the mine area are bimodal mafic and felsic volcanics rocks of the West Kahama segment of the Nyanzian age Kahama Greenstone Belt. The mafic rocks are predominantly flows, overlain by a series of felsic pyroclastics and ash tuffs. Argillites occur within the mafic flows and at the mafic/felsic contact and are the principal host for the mineralization. Mafic dykes/sills, commonly lensoid along their northwest strike, are a significant part of the lithological package southwest of the deposit itself. The Bukoli Granite, which separates the Kahama belt from the Rwamagaza belt to the west, lies approximately 3 km southwest of the mine. Together with regional faults, the Bukoli Granite forms the bounds of a rhomboid-shaped greenstone domain at Bulyanhulu.

The gold mineralization, together with copper sulphides and silver, occurs in quartz veins localized along steeply-dipping structures parallel to the regional northwest strike. Nine of these extensive quartz vein systems have been discovered so far with Reef 1, hosted by a shear zone developed preferentially along the most extensive sedimentary unit, the most significant. The ore is characterized by sub continuous lenses and veins of black quartz concentrated in narrow shear zones. An initial stage of syn-depositional barren clastic pyrite has been identified, overprinted by a polymetallic hydrothermal event associated with gold and copper mineralization. Alteration, dominantly carbonatization with the major introduction of Fe, Ca, As, Zn and S, is largely restricted to <5 m around the mineralized quartz veins. Initial fluid inclusion studies suggest the mineralizing fluid was carbonic and methane-bearing at 300-450C.

Mined using long hole stoping method.

Mineralization associated with with steeply-dipping reefs containing gold, silver and copper in sulphides.

The following processes are utilised: Crushing, Grinding, Gravity, Flotation, Carbon-In-Leach, Thickening, Cyanide destruction, Filtration and Paste Backfill.

Bulyanhulu produces two saleable products: dore and copper concentrate (around 55% of production is via doré with 45% via a gold/copper concentrate).

Dore bars are produced from Gravity and CIL plants.

Copper Concentrate is produced from the flotation plant and sold to copper smelters mainly in China and Japan.