FIVE Cummins QSK engine-powered Hitachi excavators are clocking up impressive availability at a magnetite iron ore mine in the rugged north west of Tasmania.
All five Hitachi excavators on site at Grange Resources’ Savage River iron ore mine have been hitting their availability target of 92 per cent, including all scheduled and unscheduled maintenance.
Three of the excavators are EX3600-6 shovels, each with a Tier 2 Cummins QSK60 engine rated at 1950 horsepower (hp) and an operating weight of 360t.
An EX1900-6 shovel gets its digging force from a Tier 2 Cummins QSK38 engine rated at 1085hp, while an EX1200-6 shovel is powered by a 760hp QSK23.
The excavators move about 5 million tonnes of overburden and rock per month, and are feeding 17,200t haul trucks. The excavators are operated at load factors as high as 75 per cent to 80 per cent: a true endurance test for any piece of machinery.
While Grange Resources Savage River senior operations manager Gilbert Charles has been impressed with the performance of the Hitachi fleet, he had warned his workers that even tougher duty cycles could lie ahead.
The mine has been producing more than 2.4mt of magnetite iron ore pellets and concentrate per year, with plans to ramp up production to 2.9mt in the mid-to long-term future.
Two of the 60-litre V16 QSK60 engines were changed out during 2010 after clocking up 18,500 hours. “Our tear-down analysis showed the engines could comfortably have reached the 20,000-hour mark,”
Cummins Tasmania operations manager Rob Criggie said.
The QSK38, a 38-litre V12, has proven just as reliable as the QSK60 engines, with change-out occurring early in 2011 at 16,500 hours as part of Grange’s scheduled maintenance program.
Savage River maintenance manager Greg Ling rates suppliers to the mine on service response, parts availability, product knowledge, and mine visit and phone call frequency.
“We get excellent support from Rob Criggie and his team at Cummins,” he said.