Protecting OTR tyres before damage extends product life

In 2010 Xstrata celebrated the inception of its latest coal mine. Having, purchased the Anvil NSW mine project from Centennial Coal Company Limited for some US$425 million back in September 2007, the company went on to invest close to US$1 billion in bringing the renamed Mangoola Coal Mine to production in 2011/12. According to tyre protection system producer Rud Erlau, all this makes protecting the tyres that keep an operation of this scale running is all the more important.

Located about 20 kilometres west of Muswellbrook and about 10 km north of Denman in the Upper Hunter Valley, New South Wales, Australia, the 150 mt open-cut, Mangoola is set to deliver 10.5 mt pa, run-of-mine, thermal coal for domestic use and export, grossing, at current world prices, ex-mine some US$900 million per annum over an expected 18 year mine life. Now a fully operational mine, Mangoola employs 300 directly with a further 700 expected through indirect employment opportunities. The Mangoola project was delivered three months ahead of schedule and $178 million under budget.

As you might imagine with such a large project, the machinery in use is impressive and Liebherr, CAT and LeTourneau feature high on the shopping list. Four teams of earthmovers, supported by SKF drill rigs and CAT 773 Service Carts bring the coal in. But then again this environment requires the best tools for the job. Apparently Mother Nature had no thought for miners when she laid down the Mangoola deposits. Concealed by 15-90m of sandstone conglomerate, the three 9-10 m coal seams are inter-bedded with 3-4 m thick, late-Permian, tuffaceous bands. For the unitiated, Tuff is an unforgiving mixture of volcanic rock and mineral fragments in a volcanic ash matrix formed when a combination of ash, rock and pyroclastic or tephra mineral fragments were blasted into the air by volcanic action then fell to the ground as a mixed deposit. 

The company’s L1850 loader’s Michelin X-Mine D2 60/80-57 tyres are subject, not only to heavy abrasion from the sandstone and tuff but are also under threat of sidewall damage from the unpredictable content such as razor-sharp, unweathered shards of rock.

As the only wheeled loader on site, the Letourneau is far too valuable to be standing idle for want of a tyre. Given the current availability of giant earthmover tyres and high replacement costs, Mangoola has taken pre-emptive steps to save unnecessary expense and unwelcome delays in production. From it’s arrival, new, in August 2010, Mangoola have protected the L-1850’s drive-wheel Michelins with a pair of Fels Crown X22 chains (TPCs). 

Supplied, installed and supported by RUD Australia and manufactured by RUD Kettenfrabrik of Germany, the TPCs provide the all-round protection that keeps loaders, such as the L-1850, operating to schedule. The robust, tight-meshed, 22m, ribbed links of RUDs encase the tyre, absorbing the abrasion which would otherwise damage the tyre.

While extending a new tyre’s life up to three times is a significant benefit, something else RUD TPCs are said to offer is increased productivity through assured plant availability and a significantly reduced cost per delivered tonne. According to the company, since fitting the TPCs the L-1850’s has worked over 9000 hours without reporting any unscheduled workshop visits for tyre repairs or replacements. 

New Sideflex sidewall protection system

Rudd Erlau is perhaps best know for its tyre production chains and is said to dominate this market with a 65 per cent share. However, the company recently sought to – branch out into a new direction (almost literally) with the development of the Sideflex sidewall protection system.

As we have seen in mining, quarrying and some earthmoving applications, the dump trucks, used to carry either waste, ore or coal from the workface to the processing plant, rely on large expensive earthmover tyres to carry out their tasks. This makes tyres are the single most important asset.

Depending on site conditions, these tyres can be subject to poor traction, abrasive attrition and sidewall damage. Poor traction due to soft, clayey conditions or iced up haul roads is a safety issue. A skidding 400 tonne truck is a dangerous thing. Tyre abrasion is also an asset issue. Abrasion can rapidly destroy tyres – leading to premature and costly replacement. 

For trucks, there still remains the risk of sidewall damage from sharp flints and shale-like debris and, once damaged in this way, the weakened tyre becomes a write-off with no possibility of extended life as a remould.  Although haul roads are regularly cleared of spills and rock falls, it only takes one stray flint to instantly destroy a tyre and disable a truck with the consequent interruption to productivity.

With loaders, dozers and graders tyres it is accepted practice to protect tyres from sidewall damage with chain but, while TPCs have been tried with dump trucks, the long travelling distances involved make this solution impracticable and short-lived.

So Rud-Erlau’s engineers set out to devise a special solution based on their long-established experience with steel-alloy elements. However, success only came when the team turned its attention to materials used in other industries and developed ‘Sideflex’ which sees a sturdy set of replacement wheel nuts and extensions support a simple steel ring to which is attached a fanned array of over-lapping platelets. These platelets shield the entire sidewall of the truck tyre deflecting rock fragments harmlessly away.

While the mounting components are made of steel, the all-important ‘Sideflex’ shield is manufactured from a sophisticated engineering polymer which has found many applications in the automotive and other industries. This material, which is used to protect automobiles, has a unique memory capability that enables the platelets to flex and deform upon impact and then return to their original shape without any loss of integrity. 

Fully-patented, Sideflex is available now and completes the company’s range of tyre protection products.