The mining industry at large is embracing change and finding new ways to integrate innovative waste management strategies into its operations. There are various mines mitigating risks by conducting comprehensive environment impact assessments (EIAs) and implementing sustainable solutions for the full life cycle of the mine and adopting circular economy and zero waste to land (ZW2L) strategies.

Waste management solutions provider Interwaste MD Kate Stubbs says that one of the big areas of focus is finding alternative energy sources such as waste-derived fuel production facilities.

Several technologies are available to convert waste to energy. Conversely, she says Interwaste has pioneered two types of refuse-derived fuels (RDF) at their facilities in Germiston, one solid and one liquid, and are trying to convert as much industrial waste into the product as the current capacity allows.

RDF is a solid fuel source recovered through the shredding and bailing of certain pre-sorted dry industrial non-recyclable waste.

The RDF that Interwaste produces requires no heat for drying, it is cleaner and a much higher heating value similar to that of A-grade coal, thus forming a very suitable and robust alternative to fossil fuel use, says Stubbs.

Such fuels can be used within sole/co-feeding plants and replace conventional fuels in production plants for power, steam and heat generation, cement kilns and other suitable combustion installations.

Moreover, she says rubber is one of the biggest waste streams (tyres, conveyor belts) in the mining sector and can be put through an RDF process by using technology to strip out the wire, remove beading from road tyres, cut and shred the rubber down into specific sizes for RDF use in other industries.

Stubbs says, while this is in its infancy, there is a growing need for it and from a cost perspective, it can provide a good offtake for the mining sector when considering the reuse of existing waste, the savings in carbon emissions and its aiding responsible waste management. Other processes such as thermal destruction, gasification, pyrolysis, anaerobic digestion, and landfill gas recovery can also create an energy stream. 

“Interwaste has a very successful campaign where it produces alternative fuel –  which is generated from blending suitable hazardous waste, such as hydrocarbon and chemical hazardous waste.”

The alternative fuel is currently transported to cement kilns, where it is then combusted through co-processing. This project is benchmarked to supply up to 1 000 t a month of consistent fuel a kiln.

Stubbs says that while South Africa’s mining sector only accounts for 1% of global mining exploration expenditure – waste management legislation is an ongoing pressure.

She adds that the mining sector produces a significant amount of waste, which has a large impact on the environment and communities across the country.

To mitigate this, the Polokwane Declaration initially set a target to achieve ZW2L by 2022. This was later amended to ensuring that “70% waste [was] diverted from landfills by 2022”.

ZW2L has been adopted by various mining giants, with vested interests and operations locally in support of its existing commitments to sustainable development, and to ensure compliance with the regulatory framework – this includes the National Environmental Management Act and the Waste Act.

The requirement to meet changing legislation has seen the mining sector focusing on eliminating unnecessary waste and waste generation, and to further optimising resource efficiency through sustainable product designs, recovery, reuse and recycling of products, or energy production.

This will be achieved by using the systematic application of the waste hierarchy – and implementing strategies to minimise and reduce the impact of such operations, says Stubbs.

“The positive results of remediation, removing and repurposing dormant mine dumps are now considered a de facto standard for operations.

“From a mining perspective, while this waste is not going back into the mining sector as yet, mining waste is used in such processing, contributing to a stronger reuse and repurpose mindset within the sector.”

Waste management in mining is evolving, with new sustainable and innovative solutions coming into play. As a result, mining waste management companies need to create tailored waste management services, which range from analysing and classifying waste streams; to aligning the processing thereof to current and future legislation, and then designing and implementing solutions that meet the mine’s goals, she concludes.