South African Gold
 |
The Witwatersrand gold-mining region in South Africa lies outside the city of Johannesburg and includes parts the Transvaal Region and the Orange Free State. The area ultimately provides the world with roughly 50 percent of its gold production.
The discovery of this vast deposit of gold ore came in 1886, when an Australian by the name of George Harrison and his friend George Walker, discovered an outcrop on a farm by the name of Langlaagte (Sutherland 160). This find would become known as the Main Reef Group with other reefs branching off of it. The Reef is inclined at 60 degrees on the surface and decreases to a 30 degree incline as it goes deeper underground (161). Ultimately, the gold deposit is in the form of a great arc that is 300 miles long.
The gold-mining in South Africa is very different from what people first consider when asked to picture gold mining. Images of worker panning for gold on river beds or extracting shining gold samples from open pits while not be found in the Witwatersrand. The gold ore deposits are instead composed of a grey-conglomerate which has no visible golden shine. Instead, the gold is present as tiny particles within the ore and therefore must be extracted. Some believe this gold rich conglomerate formed from and ancient river bed or sea with the water breaking up the gold into tiny particles. Others believe that the gold intruded the conglomerate after it formed (Sutherland 169). Therefore, the mines of South Africa are composed of deep honeycomb grids with shafts going to depths of over 3000 feet. Shafts are dug until they pass the ore deposit and then horizontal cross-cuts or branches extend out from the stem. All that is seen from the surface are huge piles of waste and debris known as “slime dams” or “sand dumps” that mark the outskirts of Johannesburg (Sutherland 170). Overall, the industry employed 500,000 people as of 1969 and is “the principal source of income for the Union of South Africa” (166).
The process of mining in the South African region first involves the swift removal of ore from the mine since extraction greatly weakens the reef with pressure from the ground above. The ore is then crushed and processed in order to extract the gold from the ore. This processing involves the use of a cyanide solution to dissolve the gold out of the ore. The gold is then precipitated out of the solution and formed into bars. The bars are moved to the Rand Refinery where it is purified and made into 400-ounce gold bars, which as then shipped to Reserve Banks and sold on the gold markets of the world. Overall, it is estimated that about “70 tons of ore have to be extracted, raised, crushed, and refined in order to produce 1 lb. of gold” (Sutherland 171).