Stockpiles of mining tyres are beginning to weigh heavily on the environmental social governance (ESG) targets of mining companies.

Large tyre accumulations visible at some mining operations point to the need for the circular economy to be prioritised.

Extending the life of tyres for as long as possible in mining conditions and then providing recycling options at the tyres' end-of-life is ESG in action.

Ideally, the recycling should enable old waste tyre material to become an integral part of new tyre production.

At the forefront of taking tyre circularity to the highest possible level through thermal conversion is mining tyre group Kal Tire, which has been advancing its intellectual property (IP) of thermal conversion intensively in recent years.

Importantly, thermal conversion of off-the-road (OTR) tyres is able to recover large volumes of fuel oil, major steel tonnages and bountiful carbon black for reuse in new tyre production at a time when mining jurisdictions the world over will likely require some form of mine tyre circularity in the near future.

The company's focal point is its facility in northern Chile, where end-of-life ultra-class tyres are converted to their base elements of carbon black, oil and steel so that these recovered materials can be reused in new products instead of raw materials.

Set up in response to end-of-life tyre legislation in Chile, the facility's thermal conversion processes use heat and friction to induce a process that sees virtually 100% of the tyre reused.

To find out more, Mining Weekly put these questions to Kal Tire VP Southern Africa John Martin. (Also watch attached Creamer Media video.)

Are mining tyres being recycled now?

On a global scale, to a certain extent, they are. There are various options that are being used right now, for example, shredding of tyres, or something called devulcanisation or creating rubber crumb. But let's say from a Kal Tire perspective, that's probably more repurposing of the tyre than recycling. Our thermal conversion solution is, for us, probably the most self-contained recycling facility available in the world, designed specifically for mining tyres. In South Africa, the Waste Bureau is responsible for the abatement of tyres, but we certainly wish that could be expanded now to include the mining side of it.

Why would a company like Kal Tire want to invest in the R&D to create mining tyre recycling technology?

First of all, I think it's the right thing to do, and secondly, it was identified as a requirement, probably close to ten years ago, that this is something that the industry needs, primarily driven out of Chile, where legislation then forced, if I can use the term forced, the industry to start with the recycling process. Kal Tire saw that as an opportunity to extend the services, the quality of the services, and obviously these innovations that we bring to the industry. It's a long-term project, of course, and it's not just Chile that requires it. Essentially all mining jurisdictions around the world will require some form of tyre recycling in the future.

How does thermal conversion OTR tyre recycling work?

In general, it's a relatively simple process, but it's quite complex in the way that it culminates in the technology that's inside the facility. We simply collect the tyres from the mine. At that point, we take ownership and custody of the tyre. It's documented from its serial number, and we can then provide evidence to the mine owners that their tyres have been recycled in an ethical and sustainable manner. It gets delivered to the facility, we size it, we clean it. It gets put into the chamber, goes through a pyrolysis-type process, and we generate products at the end that can then go back into the circular economy - simply things like oil, steel, carbon black, etcetera.

What can South Africa learn about how this technology and legislation was successfully adopted in Chile?

The legislation was, of course, key. The legislation in Chile is soli...