Mine sites traditionally use compressed air for filling the tyres of haul trucks and other mining vehicles. Safe to Work speaks with Atlas Copco about how its nitrogen generators are an effective alternative to the conventional compressed air or bottled gas options.
Tyre-related issues are often the culprit for mining vehicle accidents such as explosions caused by lightning strikes or high temperature degradation. Atlas Copco believes that to reduce the likelihood of these accidents, it’s not just about the tyre or how you use it, but also what you put in it.
Using compressed air to fill tyres can accelerate wheel rust and corrosion due to the high water vapour content and 18-20 per cent oxygen molecules within the compressed air.
Unlike compressed air, Atlas Copco’s nitrogen filling for tyres can be customised to achieve purities from 95-99.999 per cent and causes far less corrosion.
Nitrogen escapes through the inner liner or tube of the tyre at a slower rate than compressed air because of its larger molecular structure, which reduces the risk of deflation and unnecessary sources of heat.
Atlas Copco product manager Sonik Barot says tyres filled with nitrogen can take up to six months to lose 0.14 kilopascals of pressure compared with just one month with compressed air.
“Nitrogen purity leads to reduced corrosion, as unlike air, there is no moisture in pure, dry nitrogen,” Barot tells Safe to Work.
“Tyres inflated with nitrogen also run cooler than those inflated with air, with some significant advantages. One such advantage is an improvement in tyre life of up to 20 per cent.
“Reducing the tyre’s running temperature can increase its tread life.”
Tyre-related accidents are a common risk at mine sites, with 33 per cent of truck fires caused by issues in wheels and tyres, according to the Western Australian Department of Mines in the 2015 Major Accident Investigation report.
With nitrogen-filled tyres running at a cooler temperature, this not only improves the tyre life and reduces the frequency of replacing tyres, but it can also minimise the risk of tyre-related fires.
“Extreme temperatures and solar radiations within a typical air filled tyre carry an increased risk of the tyre bursting or catching fire due to an available concentration of oxygen molecules. This can destroy not only the tyre but also the haul truck,” Barot explains.
“Nitrogen is an inert gas. It minimises fire risk, keeps tyres cool and prolongs tyre life.
“The cooler running temperature of nitrogen has further safety benefits beyond the prevention of fires.”
This includes improved road handling as nitrogen helps the tyres hold their shape and size more consistently.
“As tyres heat up, their inflation pressure increases, which then reduces the size of the tyre’s footprint, or the area that has contact with the road,” Barot says.
“The tyre then loses grip because of this smaller footprint so the smaller they run, the better the tyres will grip the road, increasing mine safety in both coal and iron ore mining operations.”
Operating a mining fleet comes with other tyre risks that are less preventable, including weather events such as lightning strikes.
The Western Australian Department of Mines, Industry Regulation and Safety (DMIRS) has highlighted the risk of tyre explosions due to lightning strikes, urging mining companies to review their risk assessments of both manned and autonomous mining vehicles during storms.
Barot says filling mining truck tyres with nitrogen reduces the risk of ignition if struck by lightning.
“The lightning strike hazard can cause truck tyres to explode and result in extensive damage to the upper structure of the truck, including the deck, engine and cab, destroying the entire truck,” he says.
“Tyres explode due to pyrolysis of the tyre whenever excess heat is developed in or applied to a tyre. Nitrogen keeps the tyres cooler and using it in mine truck tyres reduces the risk of a lightning strike tyre explosion.”
Barot further stresses that the lightning strike hazard is common, as Australia’s weather patterns have proven each year.
“Lightning storms can develop and strike anytime and the risk of injury or damage should not be taken lightly,” he says.
“As an inert gas, nitrogen will not aid combustion inside the tyre.”
Atlas Copco provides on-site nitrogen generation solutions to safely fill mine truck and long haul tyres, while also assisting miners to produce their own nitrogen for additional site operations.
With its optimised nitrogen storage systems, plug-and-play solutions and dedicated team of service technicians on hand to assist, miners can have their own nitrogen station to lower the cost and risk of filling all vehicle tyres.
“Atlas Copco’s on-site nitrogen generators are pre-engineered and containerised or skid based to provide customers with on-demand supply that is independent of bulk deliveries or third parties. It provides you (with) peace of mind and increases mine operations uptime,” Barot says.
“The mine operations don’t need to wait on third party deliveries for this abundant gas.”
Selecting an optimal nitrogen system could not be easier, with Atlas Copco offering plug-and-play skids, secure enclosed containers, or customised combinations of Atlas Copco equipment that are tailored to specific site needs and conditions.
These can stitch into existing compressed air capacity or create a stand-alone solution and are all tested to Atlas Copco’s proven high quality and Australian standards.
Nitrogen is the world’s most abundant gas. Mining operations can combine their Atlas Copco plug-and-play solutions with on-site renewable energy solutions, which are increasing in popularity as the mining industry aims to reduce its carbon footprint and works towards carbon neutral operations.
“Nitrogen filling increases the life of the tyre and mitigates the risk for tyres used in mining. Atlas Copco’s solutions are tested to operate with optimal performance and high reliability in our harsh environmental conditions and remote operations to keep our miners operating safely,” Barot says.