PhD student (26) uncovers tonnes of ‘invisible gold’ in research
Dr Steve Chingwaru says there are 460 tonnes of gold hidden in mines across Johannesburg.
Photo: Stellenbosch University/Stefan Els
Clarence Ford speaks to Dr Steve Chingwaru.
Listen to the discussion below.
While obtaining your PhD at 26-years-old is already an achievement, Chingwaru may have uncovered what could potentially be the world’s largest invisible gold resource.
Through master’s research, which was upgraded to a PhD along the way, he discovered that there was gold hidden in the mine dumps (referred to as tailings) at the Witwatersrand mine.
Chingwaru looked at ways to characterised and extract the gold.
His research found that while big mining companies have already started processing tailing to extract gold, the traditional method through cyanide is not as effective and it is damaging to the environment.
“Cyanide has been historically the traditional way to get gold out of an ore deposit but it only dissolves exposed gold. With my research, I discovered that there is gold locked in a mineral called pyrite (fool's gold) and cyanide cannot access it, that’s why we call it invisible gold.”
Dr Steve Chingwaru, Geometallurgist
Mines also have more to gain as extraction should not be a costly endeavor compared to traditional mining.
“The most costly process in mining is the crushing and the milling which is very energy intensive. These tailings, which are on surface and don’t need to be crushed or milled.”
Dr Steve Chingwaru, Geometallurgist
“The most expensive process has already been skipped, all you have to do is add a pre-treatment step and you can unlock this gold.”
Dr Steve Chingwaru, Geometallurgist
Chingwaru estimates that there are 460 tonnes of gold hidden in plain sight in mines across Johannesburg, with a value of over R450 billion.
Scroll up to the audio player to listen to the interview.