While mining operations extract precious minerals and metals from below the earth's surface, their operations depend on something also very valuable that is above the ground – off the road (OTR) tyres.
Mining site managers are only too aware of how dependent their operations are on the maintenance of the special OTR tyres used by earthmoving machines and haul trucks.
Something as simple as a sidewall puncture on one of these specialty tyres, caused by a rock or haul road debris, can temporarily take a critical and expensive operating asset out of use. This can negatively impact mining operations workflow. Moreover, replacing an OTR tyre can cost in the tens of thousands of dollars.
The environment in which dump trucks, wheel loaders, motor graders, and other heaving mining equipment operate is severe even on the toughest of tires. It takes significant skill for a driver to navigate within a mine and get in and out of a site quickly and safely with minimal wear and tear on their tyres. Haul roads are heavily travelled, are often narrow, contain short and steep grades, and have ruts and rock debris.
Driving too close to berms or impact with a windrow, which is a mound that helps direct drivers to stay on course, can expose an OTR tyre to a sidewall cut. At a dig, a truck can easily run over spilled materials or hit a concrete bumper block at the mine's dump pit.
Even though OTR tyres for heavy equipment are specially designed for harsh environments, the risk for damage is still high. One of the most common failure points is the tire's sidewall. Without any added protection, a tyre's sidewall is exposed to rocks, debris, uneven road surfaces, and high bank faces, all the while supporting heavy payloads.
Research by the Mechanical Engineering Department at the University of Alberta in 2011 on the detection of faults on off-road haul truck tyres identified five tire failure areas: tyre tread, shoulder, sidewall, bead, and liner. The study cited research by Syncrude Canada Ltd. that examined the causes for off-road tyre failure from 2005-2010. Sidewall cuts accounted for approximately 18% of all faults, sidewall separation 10%, and sidewall impact over 5%.
When the sidewall is damaged, typically by a puncture, the vehicle is not safe to operate. Because of the scale of the trucks, the tyres are specially designed and are very expensive to replace. Take the Caterpillar 797 haul truck, for example. This truck has six tyres worth upwards of $300,000.
Repairing a damaged sidewall takes valuable time to send a tyre out for repair and the repair may not be successful. A mining operator faces a sidelined heavy equipment truck and an expensive tyre replacement.
An innovative new sidewall protection solution is entering the market to protect these valuable OTR tyres. Purpose-built for use on heavy equipment operating in mining environments, operators can bolt on a polyurethane sidewall shield to prevent the sidewalls from getting punctured when operating in a mining site.
A Michigan-based firm, Argonics, which specialises in high-performance, polyurethane-based elastomers and is one of the largest producers of wear-resistant and customisable urethane products, has developed this sidewall protection. Their sidewall protector uses a proprietary urethane formulation called Kryptane, which was engineered for extreme wear conditions involving abrasion, sliding, or impact.
The special properties of urethane make it an excellent material for sidewall protection. This tough, elastic material excels in loading applications as it will change shape under heavy load and then return to its original shape once the load is removed.
Urethane offers maximum abrasion resistance, which is ideal for situations where severe wear is a problem. It is also already hard at work in mining applications withstanding abrasive ore, sand, and gravel moving through a conveyor.
The idea for applying the special properties of urethane for off-road sidewall tyre protection came from Perry Fell, Territory Manager at Luff Industries, a Canadian distributor of Argonics, who thought Argonics' expertise in high performance polyurethane elastomers would be well suited to an OTR application and proposed the original design.
The sidewall protector comprises eight integrated segments that together with a specially designed ring use 32 bolts to apply to a wheel. The entire sidewall protector can be installed in about 15 minutes once the special flange has been installed by certified personnel. If an individual segment is damaged, an operator can replace just that piece saving the cost of replacing the entire shield. Virtually no maintenance is needed other than to retorque the bolts after 15-20 hours of use - much like when installing new tyres on a car.
According to Fell, who has been overseeing product testing, the urethane-based sidewall protector has been tested for over 8 months since 2017. It has been installed on the front tires of a Caterpillar 980 - a seven cubic yard loader. The loader has been working in a quarry face with blasted rock in a site located in Ontario, Canada.
"The sidewall protector has been performing very well," said Fell. "We've had no tyre punctures or sidewall issues since installing the protectors." According to Fell the quarry is a harsh environment on the tyres as there is contact with very abrasive material from small particulates up to 24 inches in size. Fell estimates that the cost to replace tyres on the loader would be up to $12,000 for a new tire or up to $6,000 for a used tire.
Bob Welker, International Sales & Director of Marketing at Argonics, states that "We've been able to refine the sidewall protector design based on the extended testing in the quarry. There have really only been minor changes needed for things like increasing the size of the bolts."
According to Welker, the patent-pending urethane sidewall protector is currently in its fourth generation and the company is preparing to make the sidewall protector available to the market shortly. Currently the design is based on a 25" wheel diameter used by loaders such as the Caterpillar 980. The company is planning a sidewall protector for a 45" wheel diameter next. The OTR sidewall protector will be shown by Argonics at the upcoming Mining & Exploration International Conference and Expo to be held from 6 to 8 September in Las Vegas.