Overview
Barrick operates the Bulyanhulu property through its wholly-owned subsidiary Kahama Mining Corporation Limited.
The Bulyanhulu gold mine is located in northwest Tanzania. The mine consists of an underground mine, a process plant, waste rock dumps, tailing containment, water management ponds and associated facilities.
The mine is an underground trackless mining operation using long hole and drift-and-fill as its principal stopping methods.
The mine is transitioning towards narrow vein conventional mining. Transition is estimated to be completed by 2014.
As at 31 December 2009, a total of 2,673 individuals were employed at Bulyanhulu, consisting of 2,168 ABG Group employees and 505 contracted personnel.
Life of the mine as at 31 December 2009 was estimated in excess of 25 years based on its proven and probable reserves.
Location
The Bulyanhulu gold mine is located in northwest Tanzania, in the Kahama District of the Shinyanga Region, approximately 55 kilometres south of Lake Victoria and approximately 150 kilometres southwest of the city of Mwanza, a regional business and economic hub. The average annual temperatures range between 15° and 35°C. Average annual rainfall in the region is 953mm.
Geology
The Bulyanhulu mine is a narrow vein gold mine containing gold, silver and copper mineralisation in sulphides.
Mineralisation at Bulyanhulu is associated with steeply dipping reefs. To date, a number of distinct reefs have been identified.
Archean rocks host a number of sub-parallel quartz-sulphide veins ('Reefs') which have undergone extensive drilling to depths of 240 m and 3 of which have exploratory underground workings.
The drilling program has turned Bulyanhulu into at least five distinct deposits: the Main, West and East Zones, Reef 2 and Reef 0. The Main Zone hosts the majority of the existing mineral reserves and is open at depth. The East Zone was discovered in 2000, is estimated to contain 1.2 million ounces of gold and is open to the east, west and at depth. The West Zone is estimated to host almost 2 million ounces and is open at depth and to the west. Reef 0, is located about 10 meters from the current Main Zone between Reef 1 and Reef 2. Reef 2 consists of a series of mineralized structures located approximately 500 meters from Reef 1.
The proposed development was planned as a 500,000 ounce per year underground gold mine. Total cash costs for this production were projected to average less than US$130 per ounce of gold, for the initial 12 years of the mine. Total capital costs as per the feasibility study are estimated to be US$280 million.
Mining & Operation
The Bulyanhulu process plant produces a concentrate which contains gold, silver and copper for export to international smelters for specialised processing to recover the contained metals, of which on average 200 to 240 grams per tonne is gold, 150 to 200 grams per tonne is silver and 13.0 per cent to 16.0 per cent is copper.
The process plant also produces gold doré bars through gravity and a carbon-in-leach circuit. The process plant processes an average of 1.1 million tonnes of ore per year (or approximately 3,300 tonnes per day), operating 24 hours per day, on a 365 day per year basis. Shaft capacity is in the region of 5000 to 5500 tonnes per day.
The tailings from the process plant are deposited in a tailings containment area or mixed with crushed waste rock and cement to provide structural support underground. The existing tailings containment is currently being expanded to provide an estimated further four years of operating life.
Total production was approximately 249k ounces of gold in 2009 at an average gold recovery rate of 92.1 per cent. The process plant averaged a throughput of 2,627.9 tonnes of dry ore per day milled in 2009.
Process
The process plant consists of a crushing and grinding circuit, a gold/silver gravity circuit, a copper/gold/silver flotation circuit, a tailings thickening and filtration circuit, a paste backfill facility, and a tailings storage facility. The original 2500 tpd plant, commissioned in 2000, was subsequently expanded to 4000 tpd in 2001 by SNC-Lavalin.
The plant operates 24 hours per day with a capacity of 3,300 tonnes per day. The plant has a staff of 145, and process maintenance a staff of 88.
Tailings are converted to paste. Waste rock with the potential to be acid-generating is segregated and used as backfill. Approximately one quarter of the tailings is used as backfill. The remainder is deposited in surface containment cells. The cells will be reclaimed once they are full. The tailings are covered with a compacted layer to minimize water infiltration and oxygen flux that could result in acid generation and then capped with a vegetated soil cover.
Power is supplied through a 220-kilovolt overhead line connecting the property to the Shinyanga Station and is purchased pursuant to a contract with the Tanzanian Electric Supply Company, Ltd. Water is supplied through a 48-kilometer pipeline from Lake Victoria to the property.
