South Deep shaft
Over-exploitation and increasingly expensive upkeep costs to deepen gold mines have resulted in an overall reduction in gold mining as a share of South Africa’s mining economy. Gold is mined primarily from below-ground mineshafts where it is crushed into a fine sand and conveyed to the surface where it is mixed with water to form a slag. The slag undergoes cyanidation which dissolves the gold from the rock bodies, filtered, and once superheated in a smelter, the gold is separated from its impurities and poured into forms to create dore bars. Most dore bars will be flown overseas for sale to be further refined for jewelry or technological applications, with the remainder stored as investment grade bars and coins. The global price of gold has risen steadily over the past 4 decades which has incentivized mining companies to expand their operations by filing applications to open new mines farther away from Johannesburg and most notably through the re-mining gold tailings to extract its trace amounts of gold.