The coal mining sector in South Africa stands at a crossroads, grappling with the need to balance economic benefits with environmental responsibility. As the industry faces increasing scrutiny, innovations in responsible mine closure could redefine its future. Thashni Chetty, African Mining Lead for WSP in Africa, highlights the dual nature of coal mining: while it drives economic growth and provides affordable energy, it also generates substantial solid discard that can lead to environmental pollution. The legacy of ineffective mine closure in South Africa is stark, with abandoned mines and operations in prolonged care-and-maintenance posing ongoing risks.
With approximately 108 operational coal mines, the challenge of managing coal discard is significant. Traditional surface disposal methods create long-term environmental liabilities, even after mining operations cease. This underscores the urgent need for responsible mine closure strategies. Gloria Dube, a Geoscientist at WSP in Africa, advocates for integrating mine closure planning from the outset. “Ideally, plans for mine closure should form part of every mining stage to avoid the historic trend of mines being abandoned without adequate rehabilitation measures,” Dube insists.
One promising solution is in-pit disposal of coal discard. A recent study by WSP in Africa, presented by Dube at the South African Institute of Mining and Metallurgy (SAIMM) Mine Closure Conference in February 2025, explored this method as an alternative to traditional surface disposal. The study reveals that in-pit disposal can mitigate Acid Rock Drainage (ARD) and Metal Leaching (ML) impacts, aligning with regulatory compliance. “In-pit disposal offers a controlled environment that reduces oxygen exposure, a key driver of acid generation,” Dube explains. The study found that old coal discard is highly acid-generating, while fresh discard initially maintains a neutral pH but risks acidification under extreme oxidation.
The risk assessment indicates that in-pit disposal, when discard is placed below the final pit water level, can minimise ARD generation. This method prevents secondary mineral formation and eliminates the need for additional land use, making it a more responsible alternative. Aligned with the South African Best Practice Guidelines, strategic in-pit disposal coupled with timely backfilling, compaction, and rehabilitation can enhance environmental stability and safeguard groundwater resources.
Dube acknowledges that as approaches and technologies advance, plans may change. However, she stresses the importance of proactive planning. “Planning for and implementing in-pit disposal allows mine operators to mitigate their impacts as they go and keep future issues from becoming major obstacles at closure stage.” From a profitability standpoint, integrating closure from the beginning reduces end-of-life remediation costs, which can accumulate to millions of Rands if impacts are left to accumulate over the years.
The conversation around responsible mine closure is critical for South Africa, regardless of the size of the mining operation. Dube emphasises that responsible practices implemented during operations help meet changing regulatory requirements and address environmental issues throughout the mine’s lifecycle. “It doesn’t matter how big or small the mining operation is, effective and responsible mine closure is a critical conversation for South Africa,” Dube says.
As the industry shifts towards responsible mining practices, adopting in-pit disposal for coal discard offers a pragmatic solution to reducing environmental footprints while ensuring compliance with evolving regulatory frameworks. Chetty concludes, “Our study underscores the importance of innovative discard and waste management solutions in shaping the future of responsible mining in South Africa.” This shift could redefine the sector’s approach to environmental stewardship, setting a new standard for responsible mining practices globally.