When you need a tough bogger

When Oceana Gold needed an exceptionally tough loader to work the face at its Frasers Underground Mine, they turned to Goughs and a rugged Cat machine made across the ditch in Tasmania.

The conditions don’t get much tougher on a loader than the face of a gold mine in a confined space no bigger in places than five metres wide and six metres high.

Average life span of an underground loader, called a bogger, in these conditions is 24,000 hours and that’s after an overhaul at 12,000 hours. When it came time to replace the large loader at the Macraes Gold Mine in Central Otago, owner Oceana Gold turned to Goughs and an underground loader with a worldwide reputation for its rugged engineering, performance, operator comfort and longevity – the Cat R2900G underground mining loader.

As the first of its type in the country this Tasmanian-made loader drew a lot of interest when it was delivered to Macraes Gold Mine in central Otago and put to work in the development extension at Frasers Underground Mine, the biggest underground mine in the country.

“These machines have a fantastic history and reputation for reliability,” says Geoff Hender, the underground operations superintendent at Oceana Gold.

The purpose built Caterpillar designed underground mining machine is made in Tassie at Caterpillar’s heavy machinery facility in Burnie, and is the latest model. With its compact design, high engine power, high torque rise, stronger components and excellent manoeuvrability, the Cat R2900G is a solid performer and popular in underground mines around the world.

“We currently have it loading trucks bringing ore and waste to the surface from our development faces and stopes,” says Geoff.

“The unit is working in a confined space no more than 5.5 metres wide which doesn’t leave a lot of room to manoeuvre and it will take quite a pounding during over its life. We wouldn’t expect to get more than 24,000 hours from an underground loader – they are worked very hard.”

Compared to loaders designed for surface operations, underground loaders don’t do as many hours in a given shift as there’s a lot of down-time down in the mine for clearing blast fumes and other operational activities, and Geoff says the company expects it loaders to working around 500 hours a month.

“It’s performing very well and living up to all it specifications. The bucket has a capacity over eight cubic metres so can fill up a 50 tonne truck in just three passes, and we are very happy,” says Geoff

“It also has tele-remote capability which will be important for future operations.”

At the mine face the Cat R2900G has also introduced a new level of operator comfort with its ergonomic cabin and revolutionary electronics and hydraulic controls that include both electronic auto-shift or manual transmission, and low effort, pilot operated joystick controls with simultaneous lift and tilt functions, integrated steering, and transmission functions.

Integral to the cab is a rollover protective structure that is mounted to the frame to isolate the operator from vibration for a more comfortable ride. A suspension seat provides an optimal driving position and enhances operator comfort throughout the shift.

Structural components are the backbone of the R2900G’s durability and its heavy duty loader frame is designed and built to absorb twisting, impact and high loading forces. The Cat C15 engine, which is US EPA Tier 3 and EU Stage III compliant, features a new, sculptured cylinder block that provides greater strength and lighter weight. The Caterpillar Electronic Monitoring System (CEMS) continuously provides critical machine data to keep the machine performing at top production levels. A warning system alerts the operator of immediate or impending problems with the likes of engine oil pressure, brake oil pressure and the electrical system.

Likewise, the R2900G is designed for quick and easy servicing, which reduces downtime, with ground level access to all tanks, air filters, lubrication points and compartment drains. Radial seal air filters are easy to change, reducing time required for air filter maintenance, while sight gauges means quick and easy fluid level checks.

Pascal Brosnahan, Goughs business manager – mining, says it is the first time the company has sold a Caterpillar underground model in New Zealand and although the machine had only been underground at Macraes since mid winter, the client was very happy with its performance.

“They have other smaller loaders down there, but the larger Cat R2900G is being used for bogging out of the face and loading from stockpiles into trucks, and is very reliable machine for this sort of heavier work in the development side of the mine,” he says. 

The Cat comes with a lot of unique design features, he adds, that include easy maintenance, a comfortable operating system, and even Cat’s own ‘hook’ on the rear of the machine that releases the brakes if the machine needs to be towed clear of a rock fall.

“The strengthening in the frame provides excellent protection in such confined spaces, while the generous bucket size means big payload productivity.”

The deal was also packaged with Cat’s international customer support, he says.

“Parts are common with other Cat machines and supported by Goughs’ customer support team that promises to deliver prompt, dependable parts availability and service expertise, as has been provided to Oceana Gold for the past seven years at the MARC (Maintenance and Repair Contract) for the open pit operation.”