The Bulyanhulu mine is located in north-west Tanzania, East Africa, approximately 55 km south of Lake Victoria and approximately 150 km from the city of Mwanza.
At Bulyanhulu, the geology consists of mafic volcanic flows overlain by a series of pyroclastics and ash tuffs. Argillite is present at the contact between the mafic and felsic rocks.
The gold, silver and copper mineralisation on the property occurs in quartz reefs localised along steeply dipping north-west striking structures, generally localised in the argillite units. The zone strikes 310 degrees and dips steeply to the north-east. The mineralisation has been defined over a strike length of 5 kilometres and averages 2 to 3 metres wide. The most significant structure discovered on the property to date is Reef 1, which contains the bulk of the mineral reserves defined to date (2006).
At the time of acquisition by Barrick in 1999, proven and probable mineral resources were approximately 3.6 million ounces of gold. At the end of 2005, Bulyanhulu had 10.7 million ounces of proven and probable gold reserves. Drill results to date indicate that grades improve at depth.
The current reserves are concentrated on one reef but significant exploration potential has been identified on two other reefs on the property. In 2005, the mine produced 311,000 ounces of gold at total cash costs of $358/oz.
The mine is an underground trackless operation using long-hole and drift-and-fill as its principal stoping methods. Ore reserves are accessed via a surface shaft and an internal ramp system. The process plant consists of a crushing and grinding circuit, a copper/gold/silver flotation circuit, a tailings thickening/filtration circuit and a tailings storage facility.
(Source: Barrick Gold Corp., 2006)