SIBANYE-Stillwater is testing whether advances in robotics and artificial intelligence could make it possible to safely mine gold below 3,000 metres, potentially unlocking substantial resources in the Witwatersrand Basin.
CEO Richard Stewart told the Joburg Indaba in Johannesburg on Wednesday that mining safely at greater depth is the key challenge to accessing more of South Africa’s gold endowment. "If you really want a quantum change, it is how you mine it below 3,000 metres safely."
Stewart, who succeeded long-serving CEO Neal Froneman on October 1 last year, said there were opportunities to extend existing operations around the edges, but the “really big breakthrough” would be finding a way to mine safely at greater depth, giving access to high-grade gold resources.
Conditions become increasingly hostile as mines deepen. At depths of around 3,000 metres and beyond, virgin rock temperatures can approach 50°C and rise above 60°C closer to 4,000 metres, requiring extensive cooling and ventilation. High rock stresses also increase the risk of seismic events and rockfalls.
That makes removing people from the most hazardous working areas a potentially important part of unlocking deeper resources.
Stewart said conventional automation had previously not provided the answer because of the way South Africa’s narrow-reef gold mines were built. But advances in robotics and artificial intelligence were changing what might be possible.
“I remember having a conversation five years ago on gold, where somebody said, ‘But surely you can automate this, go down there.’ The answer was no,” he said.
“This is not about mechanisation, but something’s changing really quickly, and that’s robotics. Robotics and AI has suddenly made some of this look possible.”
Sibanye-Stillwater was now “starting to put some money” into testing whether the technology could work, Stewart said.
“And some of the answers are starting to come up quite positively, and if that’s yes, then there’s a whole different discussion to be had around the Wits Basin.”
The possibility comes as Sibanye-Stillwater’s existing South African underground gold mines approach the end of their current lives.
Kloof has a life-of-mine plan running only to 2026 after safety-related geological issues sharply reduced its reserves, although high gold prices could extend mining. Beatrix is currently expected to operate until 2031, while Driefontein — Sibanye’-Stillwater's deepest gold operation, reaching about 3,300 metres below surface — has a life extending to 2036.
Stewart stressed that safety would determine whether substantially deeper resources could ever be exploited. “If I cannot guarantee you we know how to keep you safe underground, we won’t send you there,” he said.