Illegal mining causing Joburg substations to collapse, says City Power

Copper extracted from live power cables, technicians threatened and shot at and collapsing substations — these are just some of the problems illegal mining poses to City Power. In the Johannesburg electricity entity’s third-quarter report, tabled in council this month, City Power says the persistent threat of theft, vandalism and illegal mining poses a significant risk to its infrastructure, efficiency and financial sustainability. The activities also affect its ability to provide uninterrupted electricity and are diverting critical resources away from planned maintenance and infrastructure development, City Power says.

“In many instances, stolen copper is extracted from live cables, posing life-threatening risks not only to perpetrators but also to operational personnel and nearby communities.” The theft of copper cable remains one of the most frequent and damaging incidents, often resulting in prolonged outages, equipment failure and expensive emergency repairs, the report says. “Illegal mining near disused or active mining belts further compounds the problem. These activities destabilise soil and underground structures, increasing the risk of land collapse around powerlines and substations.

In some cases, entire substations have had to be shut down or relocated due to safety concerns linked to underground instability.” According to City Power spokesperson Isaac Mangena, the substations most affected by illegal mining are Robertville and Roodepoort. “Illegal mining has created significant ground instability around the Robertville substation, prompting City Power to undertake geological assessments to determine the risk and appropriate actions,” Mangena said. He said a combined geotechnical investigation and Robertville substation structural analysis report was completed in June 2024.

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“The investigations identified geological conditions associated with historic mining, including fractured rock. However, continued illegal mining beneath and around the Robertville substation has significantly exacerbated these conditions, posing an increasing threat to the stability of the infrastructure. Follow-up site assessments confirmed continued ground movement and deterioration over a relatively short period, demonstrating that the impacts of the ongoing illegal activity continue to worsen.” About 5km away, Roodepoort substation identified similar signs of ground instability, Mangena said.

These included an inverter plinth beginning to cave in and a support pole that had started to tilt between site visits, while illegal mining excavations were observed near the pole. The geotechnical report considered several mitigation measures, one of which was the relocation of Robertville, but it would be costly.

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