By Roelof van den Berg, CEO of the Gap Infrastructure Corporation (GIC)
Environmental protection remains a major challenge for South Africa’s industrial sectors. Mining and construction rely heavily on natural resources, extracting and processing vast quantities of rock, sand, clay and limestone every year.
Mining operations produce enormous volumes of waste material once valuable ore has been removed. At the same time, construction projects require large quantities of aggregates to build roads, houses and public infrastructure.
Closer cooperation between these sectors could help address both challenges. By following South African National Standards (SANS) and other recognised international standards, mining waste can be repurposed as construction material, supporting a circular economy while reducing environmental impact.
Mining waste as a construction resource
Companies involved in large infrastructure projects often require vast quantities of aggregate materials. Firms such as Gap Infrastructure Corporation rely on rock, sand and gravel for road construction, housing developments and public infrastructure.
Mine tailings, the leftover materials from mineral extraction, represent a potential alternative source of these aggregates.
Rather than storing tailings in large waste dumps, mining companies could supply this material to construction projects, turning waste into a usable resource.
Practical uses for mine tailings
With proper processing and grading, mine tailings can replace several traditional construction materials.
Examples include:
• Concrete and asphalt production
Tailings sand has particle sizes similar to conventional crushed sand. It can replace natural sand in concrete or asphalt mixtures.
• Road base and sub-base layers
Compacted fine tailings provide a stable base for roads, railways and other infrastructure.
• Structural fill and embankments
Coarse tailings and waste rock can support berms, levees and highway foundations when properly compacted.
• Riprap and erosion control
Large waste-rock fragments can be sized for gabions or riprap used to protect riverbanks, bridge supports and coastal structures.
• Brick and paving block production
Clay-rich tailings can be mixed with lime or cement binders to form pressed bricks or paving blocks.
• 3D-printed concrete
Fine tailings sand can also supply the particle composition required for emerging automated construction methods such as 3D-printed concrete.
Environmental benefits of reuse
Mine tailings remain a serious environmental challenge. Waste storage facilities require large land areas and pose potential risks if not properly managed.
At the same time, traditional construction materials rely on quarrying, which can damage landscapes and ecosystems.
Reusing mine waste for construction materials offers several environmental advantages.
First, it reduces the need for new quarrying. Every tonne of tailings used in construction replaces virgin aggregate that would otherwise require blasting and excavation.
Second, it lowers energy consumption. Mining waste has already been crushed and processed, reducing the fuel needed for additional extraction and crushing.
Third, it reduces transportation emissions. Using nearby mining waste can shorten supply chains and cut diesel consumption from long-haul trucking.
Reducing risks from mine waste storage
Repurposing mine waste also helps address environmental risks associated with tailings dams.
Large waste storage areas can create long-term challenges, including structural failure risks, dust pollution and land degradation.
By removing material from these dumps for construction use, the need for expanding waste storage facilities decreases.
Over time, reclaimed land could be rehabilitated with soil restoration and vegetation, gradually restoring ecosystems that were previously lost to mining activity.
Building a circular economy for infrastructure
Reusing mining waste in construction demonstrates how industries can support a circular economy.
Instead of treating tailings as a permanent environmental burden, they can become a valuable resource that supports infrastructure development.
Implementing such solutions requires cooperation between mining companies, construction firms, regulators and government bodies. Clear standards, supply chains and regulatory frameworks will be essential.
However, the potential rewards are significant.
Reduced environmental damage, lower material costs and improved waste management could create long-term benefits for both the economy and the natural environment.
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