Gold mine scales up

NEWCREST Mining’s Ridgeway Deeps project in Cadia Valley NSW will soon become part of one of Australia’s largest underground gold mines.

NEWCREST Mining’s Ridgeway Deeps project in Cadia Valley NSW will soon become part of one of Australia’s largest underground gold mines.

When feasibility studies were carried out Newcrest considered all available options that would meet underground load and haulage requirements.

Eventually, the company decided to employ the capabilities of Snadvik Mining and Construction and its high powered 60 tonne trucks and 21 tonne loaders.

“The specs of the TH660 truck and LH621 loader matched our needs on paper,” Newcrest’s area manager Gavin Ramage said.

“But our requirement was substantial, and we needed some convincing that equipment that was relatively new to the market could perform to the standards we needed day in day out.”

A deciding factor was Sandvik’s commitment to provide two product support specialists at the mine full time, and to maintain a full inventory of key spares at their customer service centre in Orange.

“We were comfortable with Sandvik,” Ramage said.

“They’re one of the dominant world players in underground load and haul, and the service back-up they offered convinced us to go for the higher productivity their spec sheets promised.”

Newcrest has invested in the world’s biggest fleet of TH660 trucks.

Seven units are already operating at Ridgeway Deeps and two more will be delivered by June 2008.

These are working with two LH621 and two LH514 loaders.

One DL430-7 production drill rig, with a second to follow will round off the Sandvik equipment fleet at the mine.

“Basically, at Ridgeway Deeps we have a really substantial underground dirt removal exercise, so productivity takes on a special significance,” he said.

“In the TH660s we have a fleet of trucks that can match the tramming speed of any standard 55 tonne truck while carrying a 10% bigger payload, and are also comfortable manoeuvring in drives designed for conventional trucks that carry a smaller load.

“Couple this with a 21 tonne capacity loader that can fill a TH660 in just three passes, and you’re talking high productivity. On the scale of operation that we have here, that’s a serious benefit.

“The decision has proved to be sound. Equipment availability is better than 88%, and productivity is being progressively ramped up to meet our targets.

“Our service benchmark is that any piece of equipment requiring maintenance or repair must be back in service within 12 hours. We’re moving about 90,000 tonnes a month at present, most of which is waste or low-grade ore that has to be taken 1100 metres to the surface.

“Since January we’ve moved three of the trucks on to production work, taking ore from the block cave to the underground crusher in the sub-level cave.

“By mid-year, with our full TH660 fleet in place, and all driver training and familiarisation complete, the target is 180,000 tonnes a month,” Ramage said.

Newcrest’s commitment to a Sandvik fleet has produced a spin-off benefit for other mining and exploration companies in the region.

Sandvik Account Manager Tim Redmond said that in addition to Newcrest, Sandvik is servicing Northparkes and Pybar.

“We’re also completing a two-bay workshop that will be equipped to handle complete rebuilds and service exchange,” Redmond said.

Newcrest’s decision to opt for new technology over conventional load and haul equipment is paying handsome dividends, with good productivity and 88% equipment availability.

In a world where big is beautiful, it seems appropriate that what is arguably Australia’s biggest underground mine should have the world’s biggest fleet of the biggest-capacity underground trucks.

Tim Redmond

Sandvik Mining and Construction Australia

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