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Humans will do almost anything for gold.
In fact, they will even suspend themselves 2.5 miles into the Earth – braving extreme temperatures, armed thieves, and constant seismic activity – just to mine a 30-inch gold reef.
Welcome to another day at Mponeng, the world’s deepest gold mine.
The Depths of the Witwatersrand
If you own any gold, there is about a 50% chance it comes from the Witwatersrand Basin in South Africa. Gold was first discovered there in 1886, and it is speculated that the discovery may have only been possible because of an asteroid impact. The Vredefort crater, the world’s largest impact crater at about 200 miles in diameter, is now 2.02 billion years old and potentially helped reveal the Witwatersrand gold outcrops.
The Mponeng gold mine, located west of Johannesburg and owned by AngloGold Ashanti, takes advantage of some of the deepest and richest areas of this deposit. Mponeng also represents the extent to which people are willing to go to take advantage of this region’s unparalleled mineral wealth.
Each day, roughly 4,000 miners take the plunge to get to the bottom of the mine. The journey includes taking the world’s tallest elevator, which hits a top speed at 40 mph, to make their way down.
That far into the Earth’s crust, conditions are intense. Rock walls in the Mponeng mine reach temperatures of 140°F (60°C) and humidity levels often exceed 95%. To keep things cool, the mine uses a novel cooling system to manage temperatures. Over 6,000 tonnes of ice slurry are pumped into underground reservoirs, and giant fans help to spread the air flow.
Every day, about 5,000 lbs of explosives are blasted in the mine, and 6,400 tonnes of rock are excavated.
Breaking New Ground
Gold production at the world’s deepest gold mine has been declining each year, so miners going even deeper to try and get gold.
The continued search for gold in Mponeng has led to scientific discoveries. A bacterium called Desulforudis audaxviator was found in groundwater – and it’s quite unique. The bacterium exists independently from the sun, using energy from natural radioactivity to create food. Some experts think that similar life forms could exist on other planets.
The wealth of the mine has also created an unusual crime problem. Armed, illegal miners called “ghost miners” descend into the mine for months at a time, which turns their skin pale due to a lack of sunlight. This has helped create an underground (pun intended!) marketplace, where legitimate miners profit from the ghost miners’ existence. They can sell a $1 loaf of bread for $12 underground, where it is in high demand.
At the bottom of the world’s deepest gold mine, there is a 30-inch seam of gold called the Ventersdorp Contact Reef.
This is what the miners came for, but soon they will have to dig even deeper. In fact, plans are already in place to tap into neighboring gold reefs, which would extend the life of the mine beyond 2040.