South Africa’s Mponeng mine produces about a billion dollars worth of gold a year. It’s one of the deepest mines in the world, basically an underground city, and the whole massive, byzantine structure exists to mine a seam of ore less than a metre thick. That’s how valuable gold is.
The temperature inside the mine is a loathsome 60° Celsius, so to cool it there’s an ice-making plant on the surface that produces 6,000 tonnes of ice a day. “They mix it with salt and it becomes this kind of slushy slurry, and they pump it down into these pipes into a deep reservoir that sits there. Giant fans blow air over it, and the cold air descends down these registers into the deepest mining levels and reduces the temperature to a bearable 30°C.”
Along with the official miners are so-called “ghost” miners – illegal miners who have broken in and been down there so long they’ve developed an ashy pallour from lack of sunlight. SInce the entrances are the focus of security, once they’re in there’s no easy way out.
“They steal ore from there; they refine it inside the tunnel, usually using very, very toxic methods, like mercury, which no doubt poison them. Security isn’t very keen to go looking for these people because, in a mine, you can hear someone coming a long way off, and these people are armed and they wouldn’t hesitate to shoot security and get into gunfights.”
The legal miners have no incentive to get rid of them because they run a black market trade in basic overworld items that the ghost miners can’t access. “A loaf of bread that costs less than $1 on the surface costs $12 underground. Making a couple of extra sandwiches and putting them in your lunch bucket, you can make some serious extra money.”
There are so many ways that people are living in this world that you would not know about, would never occur to you (even if it’s obvious someone must be in retrospect).
Addendum from Wikipedia: “Tunnel walls are secured by flexible shotcrete reinforced with steel fibers, which is further held in place by diamond-mesh netting.” Diamond-mesh netting! I bet it doesn’t look like I’m imagining.
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