Gold worth R450 billion hiding in plain sight

Stellenbosch University’s Dr Steve Chingwaru’s findings could help unlock gold to the value of R450 billion hiding in plain sight.

Chingwaru is the grandson of legendary prospector George Nolan, who discovered lithium in Zimbabwe.

Chingwaru’s groundbreaking geometallurgy research regarding hidden gold deposits in mine dumps has garnered interest from mining companies around the globe.

Historical mine waste from the Witwatersrand called tailings, contains over six billion tonnes of material with significant gold content.

The research aimed to calculate and characterise these gold reserves. He also explored ways to extract the gold efficiently.

Invisible gold – small particles locked inside other minerals – is nothing new. However, Chingwaru’s research revealed how much gold is hidden in the mine dumps.

“Historically, the low concentration of gold inside tailings was considered too low grade to be of value,” he said.

However, because extensive mining has depleted most of the high-grade gold concentrations, gold in low-concentration sources is becoming more viable.

Some big mining companies have started processing the tailings to extract the leftover gold, but the traditional method of cyanide extraction is not very effective.

 “Typically, they manage to extract just 30% of the gold through this process. So, I asked where the remaining 70% is and how it can be safely removed from the pyrite,” he said.

He added that mining these deposits would also be good for the environment and help reduce acid mine drainage.

“If you process the pyrite, you are taking out the key cause of acid mine drainage, plus you’re getting economic value from it,” he said.

“The process has the potential to recover additional valuable byproducts such as copper, cobalt and nickel.”


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