Transforming mine waste to construct bridges and buildings through circular economy approach
In South Africa, the industrial sectors, particularly mining and construction, are grappling with the contentious issue of environmental protection. However, a promising solution is on the horizon: repurposing mine tailings in the construction industry.
By cooperating and adhering to standards, these industries can limit their environmental impact and establish a circular economy. This approach offers several environmental benefits, starting with the reduction of waste stored in tailings dams. Technologies like tailings filtration convert tailings from slurry to dry, stackable materials, enabling safer, more compact disposal or reuse in construction materials such as bricks or aggregates.
This repurposing also reduces water usage since filtered tailings require less water storage and lower evaporation losses. Furthermore, reprocessing tailings can recover valuable minerals that remain, thus improving resource efficiency and minimizing additional mining impacts.
Utilizing mine tailings in construction supports the transition to a circular economy by reducing waste, recovering resources, and lowering environmental risks. Tailings sand can replace natural sand in concrete or asphalt, while coarse tailings can serve as fine aggregate in concrete. Coarse tailings and waste rock can be used as structural filler material in embankments, berms, levees, and earthworks. Large, durable waste-rock fragments can be used as riprap or gabion stone for erosion protection.
Clay-rich tailings can be mixed with cement or lime to produce pressed bricks or paving blocks. Finer tailings can be compacted or converted for use as a road sub-base. Construction waste cannot completely replace quarrying, but it can supplement and take considerable pressure away from the sector by utilizing waste that's produced during the mining process.
The benefits of this approach are immeasurable for the health of the environment and the prosperity of future generations. Fewer truckloads tipped onto a dump mean slower waste dam expansion, lower risk of structural failure, and less toxic dust drifting across to neighboring settlements.
The mining sector uncovers billions of tonnes of aggregate annually, while the construction sector uses large quantities of rock, clay, limestone, and gravel. Companies like Gap Infrastructure Corporation (GIC) are leading the way by recycling raw material from mining companies for large public infrastructure projects.
Establishing the relationships, protocols, regulations, supply chains, and other structures necessary to achieve this goal might be difficult. However, with robust legislation such as South Africa’s National Water Act and Waste Act, and the recent establishment of global standards for tailings management, environmental safeguards are in place to ensure responsible recycling of tailings in industry and construction without harming communities or ecosystems.
In conclusion, integrating mine tailings into South Africa's construction industry offers a promising solution to environmental challenges. By reducing waste volumes, saving water, recovering residual minerals, and supporting the principles of a circular economy, this approach fosters economic opportunities and supports social licenses to operate, all while promoting a more sustainable future for the country.
[1] Minerals Council South Africa. (2021). Tailings storage facilities. Retrieved from https://www.minerals.org.za/tailings-storage-facilities/ [2] South African Institute of Mining and Metallurgy. (2019). Tailings and waste management. Retrieved from https://www.saimm.co.za/tailings-and-waste-management/ [4] United Nations Environment Programme. (2021). Global standards for the management of tailings facilities. Retrieved from https://www.unep.org/resources/global-standards-management-tailings-facilities
- By repurposing mine tailings in the construction industry, industrial sectors like mining and construction can reduce their environmental impact and contribute to a circular economy.
- Technological advancements, such as tailings filtration, allow for the conversion of tailings from slurry to dry, stackable materials, which can be safely disposed of or reused as construction materials.
- Reusing mine tailings in construction can help recover valuable minerals, improve resource efficiency, and lower environmental risks associated with additional mining.
- Utilizing mine tailings in construction not only supports a circular economy but also reduces water usage and prevents waste storage in tailings dams.
- Companies in the finance sector, such as Gap Infrastructure Corporation (GIC), are paving the way for the recycling of raw materials from mining companies for use in large public infrastructure projects.
- With comprehensive legislation like South Africa’s National Water Act and Waste Act, and global standards for tailings management, responsible recycling of tailings in industry and construction can be achieved without harming communities or ecosystems.
