Gold Standards

摘要

The Mponeng gold mine in South Africa is the world's deepest mine, extending more than 2 miles below the surface. Not surprisingly, conditions at its depths are hellish. The commute down takes more than an hour. The rock itself can reach 140 degrees Fahrenheit and occasionally explodes. But there's also a pair of gold reefs down there, the lowest of which is 3 feet thick. It costs about $550 an ounce to extract the bling—not too bad when gold is selling for $1,300 an ounce. AngloGold Ashanti, which runs Mponeng, can keep well in the black by recovering just 0.35 ounce of gold from each ton of rock, and Mponeng pulls up 6,000 tons a day. AngloGold and its chief rival, GoldFields, dug the first ultradeep mines decades ago, but only recently has technology made the operations (sort of) safe. Here's how they do it.