This researcher found billions in ‘invisible’ gold in Jo’burg’s mine dumps

At 26 years old, Steve Chingwaru uncovered 420 tonnes of gold in buried mining waste. Now everyone wants to hire him.

Johannesburg, South Africa – As a teenager living on the East Rand of Johannesburg, Steve Chingwaru thought the flat-topped mounds of rock and earth that dotted the skyline were a natural feature of the cityscape. Jo’burg isn’t very windy, but when the wind does blow – usually around August – the air is filled with orange dust. “It gets in your hair, your clothes, your throat,” says Chingwaru.

Now, barely a decade later, the 26-year-old geometallurgist is being flown up to the city of his youth on an almost weekly basis by mining companies who want him to help them extract maximum value from the mounds of orange dust. That’s because the mounds are made up of mine waste from the richest gold deposit ever discovered, and Chingwaru has just calculated that approximately 420 tonnes of “invisible gold” – with a value of $24bn – is buried in the Witwatersrand’s mine dumps.

The massive discovery came from research for his master’s thesis — that was so impressive it saw his degree upgraded to a PhD.

Soon after enrolling in a geology degree at Stellenbosch University, Chingwaru realised he didn’t want to be an exploration geologist. “Camping in the middle of nowhere wasn’t for me,” he says, flashing a winning smile. He was drawn to the nascent field of geometallurgy, which combines classic geology with metallurgy – and typically involves working at a processing plant. For his academic research, Chingwaru focused on Johannesburg’s iconic mine dumps, known as “tailings” in the industry.

“They were already extracting the gold from these tailings,” he explains. “But they were only managing to get out 30 percent of the gold they contained.” I wanted to know what was happening to the other 70 percent … Where was it sitting? Why weren’t they getting it out? Seventy percent is a lot,” he says, before breaking into an unexpected chortle.