The dozer, which is being used for a range of work at the coal mine - but primarily overburden stripping with the blade - replaced a similar-sized dozer of another make. It was delivered in early May this year.
According to Gavin Begg, Doug Hood Mining Limited's plant manager, the Komatsu dozer was selected based on the overall package offered by Komatsu NZ, plus availability of delivery.
"The D155AX-6 measured up very well against its competitors," he said. "It was certainly very well specced in terms of some of the extra attributes Komatsu provided as part of the package."
"In addition, it had a heavier operating weight and more horsepower," said Gavin.
"Since it's been delivered, our operators have been very impressed with its performance."
"Buying this dozer is a big step for us, as it's the first Komatsu dozer we've ever owned," he said.
In part, Doug Hood Mining Limited's decision to buy the new dozer resulted from its experiences with other Komatsu equipment at Stockton, including a PC1250-7 backhoe excavator for coal extraction, and three WD600-3 wheel dozers, which are used for cleaning up overburden material.
"Komatsu's backup has been very important for us, and we've been very pleased with the support it's provided for the PC1250-7 since it was delivered here three and a half years ago. And the company's support is improving all the time," he said.
"At the mine, we generally deal with Wayne Talbot, or John McElhinney, from the Auckland office."
Doug Hood Mining Limited was awarded a five-year contract to mine the Stockton Opencast Mine in December 2003, and has more than 100 items of equipment on the site.
The company's contract includes overburden removal, coal winning, ancillary works, and rehabilitation works.
With annual production of around two million tonnes of coal, Stockton is Solid Energy's largest mine. Stockton's coal is railed to Lyttelton for export to Japan, India, China and South Africa, while locally the mine also supplies the Holcim cement works south of Westport.
Komatsu released its D155AX-6 dozer in mid-2006. The dozer features Komatsu's patented Sigma blade design, a new more comfortable cab, automatic transmission with lockup torque converter and a Tier III-compliant Komatsu engine.
Powered by a Komatsu SAA6D140E-5 turbocharged after-cooled diesel engine rated at 264 kW, it has an operating weight of 39.5 tonnes and its Sigma blade has a capacity of 9.4 cu m.
According to Komatsu, the Sigma blade reduces digging resistance and provides smoother material roll up to increase blade load, increasing production compared with a conventional blade.
A power management system for the engine offers the option of economy or power modes, for lower fuel consumption.
Komatsu maintains that the combination of the Sigma dozer blade and the auto transmission with lockup torque converter result in significant fuel savings for the D155AX-6 compared with the previous model.
Overall productivity is increased substantially compared with its predecessor.
Other features of the D155AX-6 include:
- Seven-roller undercarriage, giving increased track length and keeping more track in contact with the ground for improved traction, stability and grading ability
- Use of Komatsu's K-Bogie system (first introduced on its large mining dozers) for better traction, component durability, and improved ride and operator comfort
- Automatic transmission with lockup torque converter for increased speed and power to improve fuel consumption and productivity
- Komatsu's PCCS (palm command control system), providing electronic control of key dozing and ripping functions, and allowing easier and more comfortable operation
- New quieter, integrated ROPS cab, with a new damping system for a more comfortable ride, and improved visibility through elimination of the need for a ROPS post on each side
- Komatsu's hydrostatic steering system (HSS), giving smooth, quick and powerful control in a range of ground conditions.
Brief specs of the new D155AX-6 are: Operating weight, 39.5 tonnes, powered by Komatsu SAA6D140E-5 turbocharged after-cooled diesel engine rated at 264 kW; blade capacity, 9.4 cu m; drawbar pull, first gear, 1 km/h, 50,000 kg; transmission, three-speed automatic Torqflow transmission with lock up clutch.