What moves on all fours, stands Wso tall that even basketball Wplayers can walk under it, and sports a pea-sized brain (relative to its mass, of course)? Well, certain types of dinosaur would have qualified, except that they bit the dust a few million years ago. The answer is the mammoth open-pit haulers of today. The biggest have payloads of more than 200 tons (180 tonnes) and are dimensionally equivalent to a 2-storey house.
Open pit mine operators expect plenty from these house-sized haulers. They want them to be productive, reliable and servicable. But they don’t want an 8-hour shift to be a test of driver endurance. Each of the manufacturers mentioned below believes its truck delivers the goods. Here are their stories.
Caterpillar
Cat’s biggest hauler, the 240-ton 793, is still in the first run of production. Initial deliveries are expected in 1991. This mammoth will feature a high-torque-rise Cat 3516 diesel engine that can power the truck to a top speed of more than 31 miles per hour. A mechanical drive train is the key distinguishing feature of this truck. Cat promises it will deliver 85% efficiency.
Cat’s biggest hauler currently in the field is the 195-ton 789 mechanical drive mining truck. Cat says this truck is 15% to 25% more productive than comparable competing models. The engine is a Cat 3516 diesel rated at 1,800 gross hp at 1,750 r.p.m. This, combined with a displacement of 4,211 cubic inches, a high torque rise and a flat horsepower curve, provides several advantages. Among those are excellent lugging ability, strong acceleration, efficient fuel use and long engine life.
The transmission has six forward speeds, one reverse gear and a lockup torque converter. Individual clutch modulation controlled by an electronic microprocessor eliminates sudden torque loads, and electronic shifting also prevents accidental downshifting or reversing.
The 789 features oil-cooled disc brakes on all four corners, box-section frame, four different body designs, thermally and acoustically insulated cab, and electronic monitoring systems.
Komatsu Dresser
Komatsu Dresser’s Haulpak division manufactures the 830E, a 240- ton-payload, 2,200-hp truck. The diesel engine is a Detroit Diesel 16-cylinder powerplant. More than 54 critical functions are protected by an engine-monitoring system. The electric drive is a General Electric GTA-26 with a Statex II control and GE’s 787 wheel motors. The power module is mounted on a subframe for easy changeout.
The 830E features advanced-technology, box section frame with special alloy steel; integral rops provisions; and rear tubular crossmembers. The rugged bolster and sill construction body is rubber-mounted on the frame.
Like most of its competitors, Komatsu Dresser has acoustically insulated the cab and designed it for operator comfort and efficiency. The hydraulics were designed for reliability and long service life. The system has a vertical hydraulic tank, modular hydraulic pump group, high-pressure hydraulic filtration and many more features. The hydraulics control the steering, dump body hoisting and service brakes.
The braking system is hydraulically actuated. The emergency brakes are automatically applied when steering pressure drops below 1,600 lb. per square inch.
“The 830E was designed to fit the total mining profile by providing an ideal match for today’s large shovels — four pass loading (240 tons) with 38-cu.-yd. shovels,” Komatsu Dresser states in its brochure.
LeTourneau-Titan
This company’s biggest off-highway hauler is the T-2200, a 200-ton rear dump truck with diesel-electric drive. It has on-board diagnostics for quick diagnosis and repairs in the pit and a 2,000-hp engine that attains speeds of 30 miles per hour.
Titan’s new longitudinal “v” body design for a wider target area gives improved distribution for reduced load shift and spillage. Modular electrical components and clustered service points make maintenance easier and faster.
This biggest Titan also features a twin axle-mounted, electric-drive traction motors; an electrodynamic braking system; four available pinion and bull gear ratios; and a redesigned cab. The twin, axle-mounted traction motors “produce rim pull beyond that possible with competitive wheel-mounted designs,” says the company’s literature.
Electrodynamic braking generates sufficient retarding horsepower per wheel for full-stop control without service brake assistance. This can save money on service brake maintenance and repairs.
Lectra Haul
The Lectra Haul MT-4000 rear dump hauler has been called Terex Corp.’s truck of the 21st century. The off-highway hauler, sold by Terex’s Unit Rig division, has a 240-ton capacity. A Detroit Diesel is standard equipment, delivering 2,200 hp at 1,900 r.p.m. The large Deluxe King Cab can accommodate two full-size seats and the double-paned, insulated glass provides a quiet ride.
The frame is a double box section, controlled roll made of strong, low- alloy steel. The computer-aided design incorporates large castings in critical areas. Rear brakes are hydraulically actuated, single caliper, dual 25-inch discs.
Two Donaldson air cleaners are mounted to the front of the superstructure for ease of maintenance. Full-time hydrostatic steering provides better control and a turning radius of 56 ft. (17 metres). The drive system sports an electric ge alternator, GE 787 traction motor and Statex solid-state “logic control.”
The engine compartment has been designed for easy access. The superstructure features two access doors to the top of the engine.
VME Americas
Vme’s entry in the big-truck category is its Euclid R190 rear-dump hauler. It can carry up to 190 tons (173 tonnes). There is a choice of two engines — an 1,800-hp, 16-cylinder Cummins or a Detroit diesel with the same power output and cylinder count. Both engines are turbo-charged.
The R190 comes with a General Electric 788BS wheel motor, complete with planetary assembly on each rear wheel. The braking system is all hydraulic with three calipers for each front disc brake and one for each rear brake.
According to company literature, the hauler’s frame and suspension work in unison, providing superior resistance to bending and torsional pull. Frame twisting is minimized by a trailing-arm front suspension. The Euclid body also has horizontal stiffeners that dissipate load shocks over the entire length of the body.
The Command Cab II, as the cab has been named, is rubber-mounted to isolate vibrations. Designed for quick service, the front access panel removes to reveal a main terminal contact strip, circuit breakers and fluid reservoirs for master brake cylinder and windshield fluid. A dashboard cover provides access to gauge and indicator areas. For operator comfort and ease of operation, the truck includes wrap-around dashboard, 6-way adjustable air seat, tilt steering wheel, in-dash duct work for ventilation and a host of other features.
Wiseda
Wiseda’s KL-2450, diesel-electric, rear-dump hauler, has a 240-ton (264-tonne) payload. The modular design has a box-section mainframe with tubular crossmembers and steel castings in critical areas. The truck also features a rollout engine package and a removable deck (as a unit with the cab). A 2,200-hp Detroit diesel powers the standard model. Cummins and mtu are optional engines. The electric drive system is made by General Electric.
The standard service brakes are front-wheel disc (3-caliper) and the rear is dual disc (armature speed) brakes. Also standard is a 4,000-hp maximum electric retarding system. Donaldson air cleaners with cab indicators and the roll-out power module are also part of the factory package.
The deluxe cab features an air-suspension driver’s seat, double-shell concept, and acoustic and thermal insulation. The dump body is constructed with hsla material that has increased bottom bolstering for better impact resistance and body stability.
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