The steel doors shut, a bell sounds from far below, and the cage descends. Within fifteen seconds we are traveling at nearly forty miles an hour down a shaft into the Earth. Somewhere in the dark beside us, another cage shoots past in the opposite direction, hurtling to the surface and full of rock. Soon we have gone down deeper than the Grand Canyon. Every hundred yards — every six seconds — the temperature rises by a degree. Down at the bottom of the shaft, almost three miles below the Earth’s surface and deeper than the ocean floor, the rocks are at more than 120 degrees Fahrenheit.
Gradually the lift slows and halts with a reassuring clunk. The doors open and we step out into the Earth’s crust. I switch on the lamp on my helmet and peer around at the rocks. Three billion years ago, they were the gravelly deposits of a river delta. All sorts of metals washed down from surrounding mountains that have long since eroded away. One metal in particular accumulated here. And, as a result, this tunnel leads through the heart of what is by a huge margin the richest goldfield on Earth. The West Witwatersrand goldfield in South Africa is also the deepest workplace on the planet. I am here to find out where the gold in my wedding ring came from. “Welcome,” says my guide, “to Driefontein mine, shaft 7.”
As I step out into the tunnel, I look at my ring. My wife and I bought our bands of gold back in the summer of 1979, in a jeweler’s shop in central London. We still have the receipts. But where did those rings come from? In theory, every piece of gold can be traced back to an individual mine. The gold has its own chemical fingerprint because of the impurities that come with it as it leaves the earth. But in practice, gold in jewelry is usually cast from a range of sources, and my ring defies fingerprinting. Because most of the 150,000 tons of gold ever mined is still in circulation, the gold on my finger could have been mined in Persia six thousand years ago, or worn by Cleopatra. But ever since gold was discovered in Johannesburg in 1886, the mines of West Witwatersrand have produced more than a third of all the gold ever mined.
The Earth’s crust here is a maze of different tunnels. At any one time, eight thousand men are working underground in Driefontein alone. On the whole West Witwatersrand goldfield, there are some sixty thousand miners underground. Huge amounts of water naturally course through the mine, and to keep the tunnels dry, more than 10 million gallons are pumped out every day. As the water is removed, air is sent down to keep the tunnels cool enough to work in. The mine has a refrigerator the size of a hangar dedicated to this task.
More than 20,000 tons of rock come out of Driefontein every day. In it, invisible to the naked eye, are about 220 pounds of gold — 5 grams of gold for every ton of rock brought to the surface. The rock is milled and mixed with cyanide to dissolve the gold, which can then be released from the cyanide by adding one of a range of other chemicals such as zinc. Across the Witwatersrand bush, reservoirs holding the oozing waste cover 155 square miles. Eventually, the rock is transformed into recognizable bars of 85 percent pure gold — before going off to the national Rand Refinery in Johannesburg, where it is refined to 99 percent purity.
Gold is incorruptible. Since the earliest records, humans have worn gold and hidden gold, bought and sold gold, worshipped gold, fought for gold, and displayed it as a symbol of power. Gold is soft and malleable, yet totally indestructible. It is ideal for filling teeth and for plating critical connections on computer circuit boards. But these are sideshows. Most of the gold ever mined has had no purpose other than beauty and as a source of value. More than half of all the gold ever mined is in the form of jewelry worn by hundreds of millions of people across the planet. Every Indian bride takes gold for her dowry. African peasants fleeing from wars carry gold as their only possession of value. The world’s population agrees on very few things. The value of gold is one of them.
And I have my wedding ring. I can remove it from my finger, if I try very hard and apply a little Vaseline. But it feels like a betrayal even to do it, and I hastily put it back on — such is the power of gold.