Kal Tire’s innovative method of recycling mining tyres is helping to create a more environmentally friendly mining industry.
In many ways, off-the-road (OTR) tyres can be seen as the lifeblood of a resources operation.
They have been used for decades to help move the thousands of tonnes of ore that come in and out of mines. In fact, they’re such a staple on-site that many don’t give them a second glance – or consider what is a fundamental question within the sector: what happens to mining tyres once they have reached the end of their use?
It turns out this question poses a number of issues regarding landfill, recycling, safety, and more.
“From a physical point of view, waste tyres are chemically inert, (but) there are still risks associated with storing them,” Kal Tire people and ESG manager Dominique Kesler told Australian Mining.
“Waste tyres can store water-borne pests and disease. If those waste tyres need to be moved at any point, they also pose a safety risk to employees.”
Tyres are also flammable, and tyre fires can be hard to control and extinguish if an incident were to occur.
A report published by Tyre Stewardship Australia showed that the Australian mining industry generated over 68,000 metric tonnes of waste tyres in 2019. Just one per cent of these were recycled.
There is a clear need to do something to improve this number, but there are limited sustainable solutions on offer for mining tyres, which means they can create a significant waste stream for mining operations.
Tyres don’t degrade naturally over time, but they are made from many different products that are worth recovering, including oil, steel, carbon black and syngas.
These products can be used to replace virgin fossil fuels and reduce future resource extraction.
So what can be done to change the way in which mining tyres are disposed?
Kal Tire’s tyre recycling plant in Chile is one way the company is helping to make tyre recycling easier.
“Kal Tire has developed a unique thermal conversion process that uses heat and friction in the absence of oxygen to convert the tyres back to their base elements,” Kesler said. “One hundred per cent of the material can be repurposed.
“Chile introduced legislation several years ago that mandated that from 2023 25 per cent of mining tyres must be recycled, increasing to 75 per cent as of 2027, and to 100 per cent as of 2030.
“To enable this, Kal Tire’s Mining Tire Group opened an OTR tyre recycling facility in Antofagasta in 2021 which can now handle up to 20 tonnes of tyres per day, including ultra-class products.
“By breaking down a 63-inch OTR tyre using thermal conversion, it is converted back to its fundamental elements. We see this as the optimal use as it provides a substitute for new carbon products and helps to reduce the total carbon footprint.”
Kal Tire’s Chilean plant is currently the only operational and government-authorised recycling solution of its kind in the country.
“We need to continue the conversation and find a way for mining companies to bridge the divide between boardrooms and mine sites to raise the visibility of this issue,” Kesler said.
“Mines have remediation budgets set aside for reclamation, but the challenge is to access those funds sooner versus later when there are thousands of products awaiting disposal.
“Plans for recycling tyres throughout the life of the mine really should be developed before start-up.”
Kal Tire ensured the Antofagasta facility, located north of Santiago, was built to the highest safety and environmental standards, even proofing it to withstand a magnitude nine earthquake. And in a move toward the future, Kal Tire has ensured the facility’s recycling solution is scalable and can be replicated in other mining markets.
“We know that the desire for change in the industry is real and there is a renewed focus and the drive of ESG (environmental, social and governance) in mining organisations,” Kesler said. “This is about us already having the solution to a growing problem and offering that solution to the Australian market.”
The process of thermal conversion recovers bulk oil, carbon ash and high-grade steel from the tyre. Bulk oil can be used as is or refined and used as diesel, while carbon ash, when purified and pelletised, can be refined into high-quality recovered carbon black to suit end market use.
Just one tyre conversion can recover more than 1600kg of carbon ash, 900kg of steel and 2000 litres of petroleum-based products.
“Over eight million metric tonnes of carbon black is produced worldwide each year, and 90 per cent of that is used in rubber applications. Imagine the impact mining could have on the circular economy if it worked to turn its waste tyres into a source of value,” Kesler said.
“Because carbon doesn’t degrade, OTR tyres can provide a source of carbon black which can be used to reduce pressure on primary production. Carbon ash can be upgraded and used as a replacement for new carbon black.
“The steel contained within a large OTR mining tyre is some of the highest quality bio-based products that can be refined and used to create new tyres or used as biofuel or in applications such as ANFO (ammonium nitrate and fuel oil) for blasting.
“By seeking out the highest and best use of these materials, companies can create a virtuous circle.”
Kal Tire hopes the mining industry will continue to push ahead on tyre recycling.
As a global industry, and in Australia, we need mining companies to push this agenda,” Kesler said.
“We don’t want the industry to see tyre recycling as the end of the road, but as something they can incorporate in the complete lifecycle.
“By taking a proactive approach to OTR tyre recycling, mining companies, as the end user of earth mover tyres, have the chance to better their stance as environmental stewards and boost their standing with stakeholders.
“Ultimately, a diversified and collaborative approach is required to boost uptake and accessibility in OTR tyre recycling.
“This includes government-led policy, proactive investments from mining companies, technological and product innovation from tyre manufacturers, and communication and collaboration across the complete value chain to turn these ‘waste’ products into a source of value and contribute to a circular economy.”
This feature appeared in the August 2023 issue of Australian Mining.
