MINING TYRES
becoming receptacles for water accumulation
and mosquito breeding. Colombia, Chile and
Peru are now introducing similar statutory
requirements related to earthmover tyre
recycling and disposal. “
It is not just government legislation driving
mining tyre recycling; a growing number of
mining companies are keen to demonstrate their
commitment to sustainability by adopting mining
tyre reprocessing technology.
There are two main processes associated with
the recycling of mining tyres – mechanical and
heat reduction. Tyres are torn and sheared to
create sections small enough to handle and
process – either through shredding to produce
rubber crumb, steel and other material, or heat
decomposition (typically pyrolysis) to produce
carbon, gas (oil) and steel.
“The biggest problem for mining tyre recycling
is the amount of steel that needs to be sectioned
or separated – especially the massive bead
bundles. These usually have to be separated (cut
or torn) intact from the remainder of the tyre for
separate processing or disposal. Most modern
recycling plants designed to handle earthmover
tyres firstly remove the beads, then section the
rest of the tyre into segments small enough to be
fed into a pyrolysis chamber to produce carbon,
oil and steel. This is generally the lowest cost
method to recycle mining tyres, with existing
facilities (or ones under construction) in North
and South America and southern Africa.”
The latest technology being mooted for the
recycling of mining tyres is destructive
distillation. This has the major advantage of
being able to process whole tyres (up to 63 in)
without having to firstly remove the bead
bundles and segment to tyre prior to heat
decomposition processing. It generates the same
of oxygen to decompose organic materials and
turn tyres into steel, carbon black and oil that is
upgraded to diesel – resources that can fuel the The three main outputs from mining
tyres recycled using thermal conversion – carbon
black, oil and steel. Photo Kal Tire
very mine trucks they came from and the local
economy. With traditional mining tyre recycling,
shredded tyres are sometimes shipped to develop a solution that was higher on this
hierarchy.”
Although at the time there were components
of thermal conversion in existence, there was not
countries with less restrictive emissions
standards, so they can be burned and used as
tyre-derived fuel to replace coal. We wanted to
develop a solution that would allow recycled
resources to be reused for the same purpose:
steel to steel, fuel oil to fuel oil, etc. In the
hierarchy of waste management, landfilling is at
the bottom, incineration is second to the bottom,
and reuse is second to the top. We wanted to
a working system anywhere – not for the
enormous size and weight of earthmover tyres –
so Kal Tire had to design the equipment. “We
learned as we went. Eighteen months of study
and engineering and design. A tremendous
investment. And many conversations and
calculations to ensure this would be
commercially viable.” Four years later, Kal Tire’s
products as pyrolysis – but with higher calorific
value for the carbon and oil output, and steel
that is perfectly clean and suitable for recycling
without further treatment.
While recycling produces saleable product, the
revenue from these products is not sufficient to
cover the processing cost. Because of this, the
recycling of mining tyres will not become a
mining industry standard without the
introduction of government legislation related to
tyre disposal.
Kal Tire’s Mining Tire Group has had an
extensive presence in Chile for nearly 20 years,
and says it had a vested interest in serving many
long-time customers. It decided that if it was to
deliver new mining tyres in the country, it also
wanted to be the one to take them away and
recycle them. By 2015, it began developing
relationships with the Chilean government and
began designing its first thermal conversion tyre
recycling facility.
“Thermal conversion uses heat in the absence
52 International Mining | JULY 2019
Michelin XDR3 tyres on a BELAZ 220 t truck at Lebedinsky GOK iron ore mine in Russia. Michelin says
it offers its customers a multi-level customised suite of services and solutions to help customers
better understand how the tyres perform at their sites specifically based on their site conditions