Superstars in the Super Pit

Posted: June 27, 2011 in Mining

New PC8000-6 is powered by dual Tier 2 Cummins QSK60 engines.

The Komatsu shovel fleet at Kalgoorlie’s Super Pit in WA is being upgraded with two new $17 million 
PC8000-6 machines.

 The new Komatsu PC8000-6 ‘Super Shovels’ are dual-engined Tier 2 machines, their Cummins QSK60 engines pumping out a total 4,020 hp.

The new shovels – one is already in service – join two older QSK60-powered PC8000-6 face shovels in the Super Pit. One has been in service since late 2003, the other since late 2005. 

The PC8000-6 machines, plated with an operating weight of 760 tonnes, generate massive breakout force as they help move 89 million tonnes of  gold-bearing ore and overburden a year in the Super Pit.

The Cummins QSK60 engines – 60-litre, V16 units rated 2010 hp at 1800 rpm – power a hydraulics system that pumps 8,280 litres of oil a minute to achieve maximum working force.

Australia’s highest-producing open pit gold mine, the Super Pit is the source of around 800,000 ounces of gold a year.

 Kalgoorlie Consolidated Gold Mines (KCGM) manages the Super Pit operation for joint venture partners Newmont Australia and Barrick Gold of Australia.

High utilisation targets are set for the PC8000-6 face shovels which are working in excess of 7,000 hours a year and are subjected to an exacting maintenance regime.

“Any time a machine is down there is a flow-on effect to production targets,” says Garry Giles, Komatsu project manager at KCGM.

“You can quickly have 10 to12 trucks banked up, and then these trucks have to be redeployed.”

Garry Giles drives a professional maintenance operation in the Super Pit, one that is based on Kaizen methodology, meaning ‘change for the better’ or ‘continuous improvement’.

To ensure the shovels meet the required level of availability, there is constant monitoring and critiquing of maintenance activities for improvement.

“There’s a lot of pride in what we achieve here,” says Garry Giles. “We accept the fact there’s no one else to blame but ourselves if we have a problem.

“Planned maintenance is the key… in fact, over 75% of the maintenance we carry out on the shovels is planned maintenance, and that’s world-class.

“We have people from all around the world coming here to see how we execute our maintenance practices and benchmark against them.”

Fitted with 38 cubic metre buckets, the PC8000-6 ‘Super Shovels’ are delivering up to 60 tonnes of rock at a time to the haul trucks, 40 of which operate in the Super Pit.

The shovels are digging at a rate of 1300 to 1500 cubic metres an hour, and are taking less than 25 sec for a dig-to-dig cycle – a remarkable time for such a big machine.

The Cummins QSK60 engines in the new PC8000-6 machines are Tier 2 emissions compliant. Tier 2 levels are the lowest regulated emissions in the world for off-highway engines over 560 kW (751 hp).

“Our operators are saying the Tier 2 machine is very responsive, more responsive than the older Tier 1 units,” Garry Giles points out.

The distinguishing feature of Cummins Tier 2 engines is the modular common rail fuel system. The high-pressure fuel pump generates around 1600 bar (23,500 psi) to enable cleaner, quieter and faster power delivery.

The system also prevents unbalanced fuelling between cylinders to significantly reduce engine vibration, noise and harshness. In fact, the Tier 2 engine is 80% quieter under load and at idle.

The QSK60 engines are certainly proven in the Super Pit operation, constantly handling load factors as high as 75 to 80 per cent and providing a key link in the high utilisation chain .

 

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