Transforming mine waste into feasible constructions like bridges and buildings through the implementation of a recycling-based economy
In South Africa, the mining and construction sectors consume vast quantities of natural resources each year, contributing significantly to environmental challenges. However, a promising solution is emerging: the utilization of mine tailings as construction materials.
Mine tailings, the waste materials generated from mining, can serve as a valuable source of aggregate for concrete, asphalt, and other construction materials. Coarse tailings can be used as structural filler in embankments, berms, levees, and other earthworks, while finer tailings can be compacted or converted for use as a road sub-base [1].
Moreover, tailings sand can replace natural sand in concrete or asphalt, offering a particle size and chemical composition comparable to conventional crushed sand [2]. This substitution not only reduces the demand for quarrying but also avoids or limits fuel-hungry crushing, blasting, and long-haul trucking that normally accompany fresh quarrying.
The benefits of this practice extend beyond resource conservation. By using mine tailings in construction, South Africa can make strides in water conservation, reducing environmental hazards from tailings storage, aiding land rehabilitation, and reinforcing sustainable mining practices.
Reducing the environmental burden of tailings dams is a significant advantage. Tailings storage facilities (TSFs) pose long-term environmental risks such as dam failures, water contamination, and large land footprints. By employing tailings in construction, South Africa can reduce reliance on these dams and the hazards they carry [1][2][5].
Lowering water consumption and improving water stewardship is another key benefit. Traditional tailings disposal involves pumping slurry onto dams, consuming large amounts of water that is often lost to evaporation or seepage. Tailings filtration technologies allow tailings to be dried and used in construction as stackable materials, significantly reducing water use and increasing water recycling in mining operations [2].
Promoting progressive rehabilitation and land restoration is another advantage. Integrating tailings back into construction helps facilitate land rehabilitation by reducing the volume of tailings on site and enabling earlier capping and contouring of disturbed land, which supports vegetation regrowth and long-term stabilization [1].
Utilizing mine tailings for construction materials also supports climate resilience and reduces the carbon footprint. Reusing tailings in construction avoids the need to quarry virgin aggregates, thereby lowering the environmental impact of mining for construction materials. This aligns with broader climate change adaptation and sustainability initiatives in the mining sector [3].
Strengthening regulatory compliance and social license is another significant advantage. Responsible tailings management through reuse supports adherence to South Africa’s environmental laws (such as the National Water Act, National Environmental Management Act, and Waste Act) and helps mining companies gain and maintain community support [1][2].
While construction waste cannot completely replace quarrying, it can supplement and take considerable pressure away from the sector by utilising waste that's produced during the mining process. Gap Infrastructure Corporation (GIC), which uses vast amounts of building material in large public infrastructure projects, has a need for raw waste material from mining operations. Every tonne of tailings that takes the place of virgin aggregate saves on thousands of litres of diesel [4].
In conclusion, employing mine tailings in construction within South Africa enhances water conservation, reduces environmental hazards from tailings storage, aids land rehabilitation, lowers demand for new raw materials, and reinforces sustainable mining practices. This approach, when combined with the reduction of quarrying, can lead to significant environmental improvements, fostering a more sustainable future for South Africa. [1][2][3][5]
References:
[1] Anglo American. (2020). Anglo American's tailings storage facility (TSF) strategy. Retrieved from https://www.angloamerican.com/sustainability/our-approach/tailings-management/tsf-strategy/
[2] Minerals Council South Africa. (2020). Tailings management and the circular economy. Retrieved from https://www.mineralcouncil.co.za/tailings-management/
[3] South African Institute of Mining and Metallurgy. (2020). Tailings management and the environment. Retrieved from https://www.saimm.co.za/tailings-management-and-the-environment/
[4] Gap Infrastructure Corporation. (2021). Sustainable construction: The role of mine tailings. Retrieved from https://gapinfrastructure.co.za/sustainable-construction-the-role-of-mine-tailings/
[5] United Nations Environment Programme. (2020). Tailings storage facilities: A review of the global risks and challenges. Retrieved from https://wedocs.unep.org/bitstream/handle/20.500.11822/26956/Tailings_Storage_Facilities_A_Review_of_The_Global_Risks_and_Challenges.pdf?sequence=1&isAllowed=y
- By employing mine tailings as construction materials, South Africa can reduce environmental challenges posed by the mining and construction sectors, as the use of tailings can serve as a substitute for quarrying and decrease fuel-hungry processes.
- Utilizing mine tailings in construction also supports land rehabilitation by reducing the volume of tailings on site and facilitating early capping and contouring of disturbed land, enhancing vegetation regrowth and long-term stabilization.
- The approach of using mine tailings in construction materials can contribute to climate resilience and decrease the carbon footprint associated with mining for construction materials.
- Adopting responsible tailings management through reuse supports regulatory compliance, adhering to environmental laws in South Africa such as the National Water Act, National Environmental Management Act, and Waste Act, while also helping mining companies gain and maintain community support.
- Every tonne of tailings that replaces virgin aggregate in large public infrastructure projects, like those managed by Gap Infrastructure Corporation, can save thousands of litres of diesel and alleviate the demand for new raw materials.
