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Coal Mining Equipment Bigger is better for Liebherr - Liebherr Mining Equipment Co Company's newest diesel electric, 360-ton mine haul truck ushers in next round of tonnage race; first unit delivered to Wyoming mine In keeping with the "bigger is better and more efficient" philosophy in the mining equipment industry, Liebherr Mining Equipment Co. of Newport News, Va., has delivered the first model of its newest large haul truck, the T282, a rigid frame, twin axle, diesel electric unit with a payload rating of 360 tons (327 metric tons). "The industry is pushing manufacturers of mining equipment to create larger capacity trucks," said Bill M. Lewis, P.E., vice president of engineering for Liebherr Mining Equipment. "Mine superintendents are constantly trying to improve their cost-per-ton efficiency, one way to do that is to use larger capacity equipment. "It was this demand, coupled with the availability of suitable components and technology, that fueled Liebherr's development of the T282 diesel electric haul truck. We realized that for the project to be successful, there had to be a proper match of components." The first T282 truck has been delivered to Arch Mineral at the Thunder Basin mine in Gillette, Wyo. The vehicle is a giant, even among haul trucks, which have grown remarkably over the last two decades. The vehicle measures 47 ft. 6 in. long, 28 ft. 7 in. wide, has an unloaded weight of 443,000 lb. and an operating loaded weight of 1,163,000 lb. This breaks new ground for load capacity of rigid frame, two-axle haul trucks and raises the bar one more notch. The rock body for the T282 has a capacity of 251 cu.yd., while the coal body has a capacity of 471 cu.yd., according to Liebherr. The T282 truck is powered by Detroit Diesel's newest large engine, the series 4000, which is a joint development between DDC and MTU. The 16V4000 diesel engine used in this application is turbocharged and charge-air cooled, has a total displacement of 64 L, and is rated 2750 gross hp at 1900 rpm, with 8064 lb.ft. of torque at 1500 rpm. The engine uses separate circuit charge-air cooling and is controlled by Detroit Diesel's fourth-generation DDEC engine management system. Other engine features include four turbochargers, inboard exhaust manifold and a common rail fuel injection system with pilot injection. The pilot injection system is designed to lower engine noise and promote more complete combustion, according to Detroit Diesel. The engine package for the T282 truck, which is mounted to the frame via Buckhorn Rubber isolation mounts, includes a Donaldson air cleaner and muffler, along with an L&M Mesabi radiator. The engine drives a Siemens A320 a.c. alternator, which provides power for the a.c. electric drive system. The generator rotor is connected via a flex plate directly to the flywheel. The Siemens a.c. drive system is based on technology used by Siemens Energy and Automation, Inc., in applications including shovel drives, locomotives, and mass transit drive systems. The system includes Siemens/Liebherr wheel motors and a blown grids continuous extended range retard speed control. The a.c. control system provides an additional margin of braking, allowing total dynamic retarding capacity up to 6032 hp while maintaining maximum torque down to 0.5 mph, at which time the service brakes are activated to achieve the final stop. The a.c. control system can advise the operator of the vehicle's operation outside the retarding capability. The new Liebherr electric traction motors used on the T282 have a unitized configuration, with a plug-in motor mounted inboard and a two-stage planetary gear set outboard. The standard gear ratio will provide a maximum speed of 40 mph without sacrificing performance on grade, according to Liebherr. The wheel design provides for inboard armature speed braking. A Rockford Powertrain driveshaft connects the tail shaft of the generator to a Funk hydraulic pump drive. The pump drive powers two Geartek Fluid Power gear pumps that provide flow for the raise and lower functions of the dump body. The twin pumps each have a displacement of 33.5 cu.in. and a flow of 299 gpm at 2057 rpm. System relief pressure is 3000 psi.
