The second of two 800-tonne Hitachi EX8000-6 hydraulic excavators has been commissioned at BHP Billiton’s Mt Keith Operation nickel ore mine in central-east WA.
The new excavator will join what was, at the time of its commissioning in February this year, the first of the machines to be commissioned in Australia.
The new machine at Mt Keith will bring the number of the machines operating throughout the world to six.
The flagship of the Hitachi excavator fleet, the giant digger is powered by twin Cummins QSK60 Tier II, US emission-compliant diesels, each developing 1450 kW at 1800 rpm.
Maximum torque is 20,100 Nm (2 x 10,050 Nm). Configured as a face shovel and equipped with a 43 m³ bucket, the excavator will be loading out 240-tonne rear dump trucks at Mt Keith.
“There has been much local and international interest in the performance of the EX8000 at Mt Keith,” Hitachi Mining general manager Peter Ross said.
“Reports from the site indicate it is meeting and in some cases exceeding the operating requirements. We are looking forward to the introduction of the second machine and its impact on productivity.”
The big digger is constructed around a rigid box design to resist bending and twisting, and uses a swing system pioneered on the company’s 300-tonne EX3600 excavators. High-strength piston rods and cylinder tubes are used throughout.
Cylinder cushion mechanisms are provided for boom, arm, bucket and dump cylinders and a flow-retarding stroke-end control system is fitted to the arm and bucket cylinders.
The Hitachi-developed Electronic Total control System (ETS) operates through an electric engine-speed sensing control system to manage the machine’s sixteen variable-displacement, axial piston main hydraulic.