Tyre protection chains fortify hardcore mining fleet

Since its purchase in September 2007, Xstrata has invested $US1 billion to bring the Mangoola coal mine to production in 2011-12.

Located 20km west of Muswellbrook and 10km north of Denman in the Hunter Valley, the 150 million tonne open cut mine is set to deliver 10.5 million tonnes per annum run-of-mine thermal coal for domestic use and export, grossing (at current world prices) $US900 million per annum over 18 years.

The mine transports coal by train to Macquarie Generation?s Bayswater and Liddell power stations and to the port of Newcastle for shipment to Far East customers.

With first class equipment and a 300-strong skilled workforce, the Mangoola project was delivered three months ahead of schedule and $US178 million under budget.

Site preparation and infrastructure improvements began in January 2009. By February 2010, the earthworks, coal handling and preparation plant and the rail facility were in place. Overburden stripping began in August 2010 and by November, the first run of mine coal was stockpiled. On 23 February, 2011, the first coal wash occurred and was trained out 11 days later.

Four teams of earthmovers bring in the coal. A 1250kW Liebherr R9400 backhoe excavator, equipped with a 40-tonne bucket, heads one waste stripping and coal excavation team. Five 195-tonne Cat 789 dump trucks, a Push Cat (RTD) and a tracked Cat D11 dozer complete the set.

A second team consists of a 959kW Liebherr R9250 with a 17m3 bucket and 11m dump height, six Cat 789 dump trucks with combined carrying capacity of 2400 tonnes, two 433kW Cat D10 tractor-dozers and a 854K Push Cat (RTD).

Designated for waste disposal duties, with an operating weight of over 660 tonnes, is a 2240kW Liebherr R966 crawler face shovel, sporting a 60-tonne bucket, supported by two 240-tonne Cat 793 dump trucks, two 634kW Cat D11s, a 7.3m wide Cat 24M grader and a 100-tonne Cat 777 water cart.

Delivered in September 2009 were a LeTourneau L1850 loader, six Cat 793s with a combined haul capacity of 1440 tonnes, a 16M grader with a 4.9m moldboard, a Cat D10 dozer and another Cat 777 water cart.

The L1850 features a 54-tonne bucket as standard equipment. Powered by a 1419kW diesel engine, it centre-loads most haul trucks with payloads from 236 to 327 tonnes.

Mother Nature had no thought for the miner when she laid down the Mangoola deposits.

Concealed by 15m to 90m of sandstone conglomerate, three nine metre to 10m coal seams are inter-bedded with three to four metre thick late Permian tuffaceous bands.

Mangoola?s tuff is an unforgiving mixture of volcanic rock and mineral fragments in a volcanic ash matrix formed when 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 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 under threat of sidewall damage from razor-sharp, unweathered shards of rock.

As the only wheel loader on-site, the LeTourneau is too valuable to stand idle for want of a tyre when it should be loading trucks. Given the limited availability of giant earthmover tyres and high replacement costs, Mangoola has taken steps to save expense and reduce downtime.

Since its arrival in August 2010, Mangoola has protected the L1850?s drive-wheel Michelins with a pair of Fels Crown X22 tyre protection chains (TPCs).

Manufactured by RUD Kettenfabrik of Germany and supplied and installed by RUD Australia, the TPCs provide the all-round protection that keeps loaders like the L1850 operating to schedule.

The robust, tight-meshed, 22m ribbed links of RUD?s Fels Crown chains encase the tyre, absorbing the abrasion that would powder the tread and, by deflecting sharp rock fragments, preventing sudden death sidewall penetration.

As well as extending a new tyre?s life by up to three times, RUD TPCs guarantee productivity through assured plant availability and a reduced cost per tonne.

Since fitting the RUD TPCs, the L1850 has worked more than 9000 hours without reporting any unscheduled workshop visits for tyre repairs or replacements.

Source: RUD Chains

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