By Prosper Makene
Tanzania’s gold produced by large-scale miners slightly decreased to USD 444 million in the quarter ending June 2022 from USD 469 million in the similar quarter in 2021.
“This was associated with closure of Buzwagi Gold Mine in June 2021,” the Tanzania’s Central Bank latest report for the quarter ending June 2022 said.
However, in the financial year 2014, the company produced a combined amount of 719,000 attributable ounces of gold.
Buzwagi Gold Mine was situated six kilometres south-east of the district of Kahama in the Shinyanga region. The mine was 100% owned and operated by African Barrick Gold (ABG), a subsidiary of Barrick Gold Corporation.
It was the single largest open-pit mining operation in Tanzania. Approximately 2,099 personnel were employed at the mine by December 2011.
ABG purchased the Buzwagi mine in 2000. The feasibility studies of the mine were completed in 2006. The development of the mine began in 2007 and was completed in 2009. The mine commenced operations in May 2009 and was shut-down in 2021.
The Buzwagi mine produced 196,541oz of gold in 2011, which was six percent higher compared to the production in 2010. The failure of the semi autogenous grinder (SAG) motor at the mine’s processing facility in May 2011 caused the production levels to fall by 15,000oz of gold.
Porphyritic granite geology and gold and copper reserves at Buzwagi mine
The Buzwagi gold mine was lies in a fleece-hosted quartz-veined deposit which comprises of porphyritic granite. Proven and probable reserves at the mine as of December 2011 stand at 61.4 million tons (Mt) graded at 1.47g/t Au (2.9Moz gold equivalent) alongside 0.114% Cu (154Mlbs copper equivalent).
Buzwagi was been developed as an open-pit mine and is being mined using a truck and shovel method. Extraction of the ore includes drilling, blasting, loading and hauling. The infrastructure being used for mining encompasses three excavators, Komatsu shovels, dozers, front-end loaders, 15 haul trucks and three blast hole drill rigs.
The ore extracted is transported to the processing facility by 150t capacity haul trucks. The processing plant can treat 12,000 tons of ore each day. It features two Knelson KC-XD48 concentrators, CS2000 ACACIA reactors, a primary jaw crusher, a SAG mill and a flotation and carbon-in-leach circuit.
The run of mine ore was broken down to a high degree of fineness in a primary jaw crusher. The crushed ore is transferred to the SAG mill for grinding. The ground ore is conveyed to the Knelson KC-XD-48 concentrators and CS2000 ACACIA reactors to produce oxide ore.
The oxide ore was treated by the gravity, flotation and carbon-in-leach (CIL) circuit. It is transferred to the cyanide leach tanks containing leach solution to generate pregnant solution. The solution was moved to the adsorption tanks where the gold attaches to the surface of the carbon. The gold was separated from carbon in a gravity and floatation circuit. The solution is transferred to the tailing storage facility for reuse.
The gold precipitates were transferred to the smelter to produce pure gold dore bars by washing the precipitates with high pressure sprays followed by drying and melting.
The Buzwagi mine was accessible by an adjacent paved highway, a 1,580m airstrip and the Isaka railway hub, which connects to the Port of Dar es Salaam on the Indian Ocean.