Ore Processing
Trucks transport the ore from the mining pits to processing operations. Some ores may be stockpiled for later processing.
We feed ore into a series of crushers and ball mills to reduce the size of the ore particles and expose the mineral. Water is also added, which turns the ore into a slurry. We send this slurry to leaching tanks, where we add cyanide solution to the slurry, which leeches gold and silver into the solution. This process removes the gold and silver from the ore. Carbon granules are then added to the solution. The gold attaches to the carbon and is pulled from the solution. We then “strip” the gold from the carbon by washing it with a caustic cyanide solution. The carbon is later recycled. Next, we pump the gold-bearing solution through electro-winning cells, which extract metals from the solution using an electrical current.
After gold has been processed, the leftover waste material is called tailings. Tailings contain small amounts of cyanide and other hazardous chemicals, so they must be disposed of in an environmentally safe way. We use the state-of-art Filter Press system to recycle all the wastewater and reuse them in the production system. The tailings which is now consist of only solid waste are stored in tailings dams, which are lined with impermeable layers. While the cyanide levels in the dam are minimal and safe, steps are taken to keep wildlife away from the dams.
We then smelt the gold, which melts it in a furnace at about 1,200 degrees celsius. From there, the liquid gold is poured into molds, creating doré bars. Doré bars are unrefined gold bullion bars containing anywhere from 60 to 95 percent gold. We finally sell the bars to a refinery for further processing into pure gold.