‘Ticking timebomb’: Abandoned mines threaten sinkholes and earthquake

Experts warn abandoned shafts and zama zamas fuel seismic danger. Picture: Gallo Images South Africa’s mining towns are living on borrowed time. Experts warn that thousands of abandoned shafts, compounded by illegal zama zama operations, are destabilising land and raising the risk of sinkholes, tremors and even earthquakes.

With acid water eating away underground pillars and millions of tons of rock removed illegally, communities from the West Rand in Gauteng to Mpumalanga face a looming disaster unless government accelerates rehabilitation and mine‑water management. Mining expert David van Wyk said the situation needed urgent attention because there would be a disaster. The problem starts when shafts left behind by mining firms are filled with water during heavy rainstorms, Van Wyk said.

“The abandoned mines, which are a crime, no longer pump out the water from the abandoned tunnels. The water interacts with iron pyrites, sulphur and copper and mixed with oxygen becomes acidic,” he said. The acidic water eats away the conglomerate and the dolomitic substructure, which then causes the sinkholes, Van Wyk said.

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The sheer weight of the water, combined with the acid water eating away the pillars in the underground chambers, will cause collapses, which will translate into tremors and quakes. “These might occur along the Main Reef Road to the south of Nigel through to Orkney. Abandoned mines cause this.” Van Wyk said other worse affected areas include the West Rand’s Merafong, Khutsong, Randfontein, Thulani and Doornkop in Soweto.

While in Ekurhuleni the affected areas are Springs, Benoni and Boksburg. Council for Geoscience spokesperson Mahlatse Mononela said the country was facing a disaster. “We are aware of inherent land stability risks associated with legacy mines and are working on mitigation, rehabilitation and reclamation plans with affected stakeholders,” said Mononela.

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