With first class equipment and a skilled work-force, the Mangoola project was delivered three months ahead of schedule and US$178 million under budget. Site prep and infrastructure improvements kicked off in January 2009 and by February 2010, the earthworks, the coal handling and preparation plant, and the rail facility were in place. August 2010 saw commencement of overburden stripping and by November that year the first run-of-mine coal was being stockpiled. Just three months later, February 23, 2011, the first coal wash took place and was entrained just 11 days later.

Four teams of earthmovers produce coal. One team relies on a Liebherr R9400 excavator equipped with a high-capacity 22 m³/40 mt bucket and five 195-ton Cat 789 haul trucks. A second team, also engaged in waste removal and coal extraction, consists of a Liebherr R9250 with a 17 m³ bucket and six CAT 789 haul trucks. Designated for waste disposal duties, the third team uses a Liebherr R966 face shovel sporting a 34 m³/60-mt bucket, supported by two, 240-ton Cat 793 haul trucks. The core unit for the fourth team is a LeTourneau, L-1850 loader, and six CAT 793 haul trucks. The L-1850 has a 30 m³/54 mt bucket as standard equipment. Powered by a 1,419 kW diesel engine, the L-1850 is designed to center-load most haul trucks rated for payloads between 236 and 327 mt.

Mother Nature had no thought for the miner when she laid down the Mangoola deposits. Concealed by 15 to 90 m of sandstone conglomerate, the three 9- to 10-m thick coal seams are inter-bedded with 3- to 4-m thick, late-Permian, tuffaceous bands. 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 L-1850 loader’s Michelin X-Mine D2 60/80-57 tires are subject, not only to heavy abrasion from the sandstone and tuff, but are also under constant 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 an asset to be standing idle for want of a tire when it should be earning its keep loading trucks. Given the current limited availability of giant earthmover tires and high replacement costs, Mangoola has taken the practical pre-emptive steps to save unnecessary expense and unwelcome delays in production. From its arrival, new, in August 2010, Mangoola has 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, 22 m, ribbed links of RUDs FELS CROWN encase the tire, absorbing the abrasion which would, otherwise, in no time, powder the tread and, by deflecting sharp rock fragments, preventing sudden-death, side-wall penetration. While extending a new tire’s life up to three times is a significant benefit, another big plus of owning RUD TPCs is seen in the guaranteed productivity through assured plant availability and a significantly reduced cost per delivered ton. Since fitting the TPCs, the L-1850 has worked more than 9,000 hours without reporting any unscheduled workshop visits for tire repairs or replacements. www.rud.com.au