A second life for mine waste

A rehabilitated waste rock dump at Kumba Iron Ore’s Sishen mine in South Africa is set to serve as the country's first embedded solar photovoltaic (PV) project on rehabilitated mine waste, marking a major step forward in sustainable land use. The 63 megawatt (MW) facility, located near Kathu in the Northern Cape, will be constructed on the rehabilitated G80 waste rock dump, transforming previously disturbed mining land into a renewable energy asset. This initiative, which reached financial close, aims to generate approximately 150,000 megawatt-hours (MWh) of electricity annually, significantly reducing the mine’s carbon footprint by around 140,000 tonnes per year. The project is a joint venture between Envusa Energy and the Sishen Iron Ore Company Community Development Trust, with the latter holding a 10% stake. All generated electricity will supply the Sishen mine, ensuring that the site continues to contribute economically even after its operational phase concludes. Envusa Energy’s chief executive, Nicole Mason, emphasized the importance of integrating renewable energy infrastructure into previously disturbed land rather than competing with agricultural or residential zones. “This approach supports rehabilitation while avoiding the sterilization of productive land for other uses,” she stated, highlighting the project’s role in setting a precedent for other mining operations. The 20-story-high waste rock dump spans roughly 100 hectares, requiring advanced engineering solutions to address long-term ground settlement. Adjustable solar mounting structures and a mobile substation were incorporated to ensure the stability and functionality of the facility over time. These innovations underscore the complexity of repurposing such terrain for renewable energy production. Experts believe the project exemplifies a broader trend in South Africa’s mining sector, where rehabilitated sites are increasingly being considered for alternative uses beyond traditional agriculture or urban expansion. Mariette Liefferink, CEO of the Federation for a Sustainable Environment, praised the initiative as a significant innovation, noting that it goes beyond merely installing solar panels. Instead, it demonstrates how formerly disturbed land can be revitalized into productive infrastructure. “Instead of viewing rehabilitation as the end of mining, it integrates rehabilitation with future economic land use,” she explained. South Africa’s mining industry has left behind thousands of hectares of disturbed land, prompting ongoing discussions about how these areas can be effectively repurposed. Renewable energy is emerging as a promising solution, especially where existing road and electricity networks are already established. Researchers from the Global Energy Monitor (GEM), a U.S.-based non-governmental organization, recently identified 18 potential conversion sites in Mpumalanga, covering about 250 square kilometers of coal mines. These sites could collectively produce nearly 13 gigawatts of solar energy, accelerating the nation’s transition to clean energy while addressing the environmental impact of past mining activities. Globally, abandoned or soon-to-close coal mines possess sufficient potential for solar energy generation to meet the annual electricity demand of a country the size of Germany. Liefferink highlighted the substantial potential of renewable energy as a key post-mining land use, particularly in regions like the Northern Cape, Mpumalanga, Limpopo, Gauteng, and North West, where large tracts of disturbed mining land exist. She stressed that these areas represent opportunities for long-term economic value creation through sustainable practices.