Haul trucks are off-highway, rigid dump trucks specifically engineered for use in high-production mining and heavy-duty construction environments. Haul trucks are also used for transporting construction equipment from job site to job site. Some are multi-axle in order to support the equipment that is being hauled.
Most haul trucks have a two-axle design, but two well-known models from the 1970s, the 350T Terex Titan and 235T Wabco 3200/B, had three axles.  Haul truck capacities range from 40 short tons (36 long tons; 36 t) to 496 short tons (443 long tons; 450 t).
Large quarry-sized trucks range from 40 to 100 short tons (36 to 89 long tons; 36 to 91 t). A good example of this is the Caterpillar 775 (rated at 70 short tons [62 long tons; 64 t]). Quarry operations are typically smaller than, say, a gold/copper mine, and require smaller trucks.
As a rule, these dump trucks can be distinguished from other trucks (in particular, dump trucks) by the following features:
- the tipper body is made of very strong steel plate; its front is extended above the driver's cab to protect the cab; the entire bottom, or rear of it, points upward;
- in some cases the driver's cab is only half the width of the truck;
- no axle suspension;
- powerful brakes;
- limited speed and operating range;
- special tires used for driving on the ground;
- due to the robust design the ratio of dead weight to payload does not exceed 1:1.6
- the body can be heated by exhaust gases to prevent the transported material from sticking or freezing.
Dump trucks are classified by:
- type of unloading (inclined or forced);
- the direction of discharge (side, rear);
- type of body (hopper, platform, sliding hopper, sliding platform).
Ultra class edit
The largest, highest-payload-capacity haul trucks are referred to as ultra class trucks. The ultra class includes all haul trucks with a payload capacity of 300 short tons (270 long tons; 270 t) or greater. As of October 2013[update], the BelAZ 75710 has the highest payload capacity, 450 metric tons (440 long tons; 500 short tons).
A rear-eject configuration is an alternative haul truck body style. Instead of lifting the bed vertically, the hydraulic cylinder pushes a ram-face horizontally through the body to eject the hauled load.
Rear-eject dump vehicles were first introduced in the 1980s by LeRoy Hagenbuch, P.E. of Philippi-Hagenbuch, Inc., for a refuse hauling application in New York City. They were designed to work on Volvo BM truck chassis. While the functionality of the ejector bodies worked well, they were prone to maintenance issues and were not replicated until the 1990s. The next documented ejector bodies were developed by DDT, a UK truck manufacturer. A variation using steel chains instead of a hydraulic ram was introduced by Bell, but did not become popular.
Caterpillar Inc. began offering a rear-eject option using technology originally designed for its scrapers after one of its contractors successfully converted a few CAT D400 models. The new design, installed on the company's D400E model, was less likely to jam in cold weather. CAT later began manufacturing a standard R.E. body for its 730, 740, and 740B articulating haul-truck series.
Philippi-Hagenbuch, a company specializing in truck body design, developed its own mechanism for its rear-eject bodies, and has patented its design in the US, Europe, and Australia. The company customizes Rear-Eject bodies or trailers for several manufacturers' off-highway vehicles; including both rigid and articulating varieties.
Rear-eject vs. end-dump edit
Because rear-eject bodies do not lift, or move externally in any way, they maintain a lower center of gravity. This means more stability on uneven terrain where the truck might tip over during the dump process. The truck can also be driven while dumping is in progress; this reduces subsequent time and effort spent on grading the dumped material.
Rear ejects are typically better suited to completely eject sticky material, preventing "carry-back."
A rear-eject truck can deliver a load in an area with a low overhead barrier.
Notable examples edit
|BelAZ 75710||BelAZ||2013||496 short tons (443 long tons; 450 t)||diesel-electric||
Employs 8 tires, on two axles, with all-wheel drive, and all-wheel steering.
|Liebherr T 282B||Liebherr||2004||400 short tons (360 long tons; 360 t)||diesel-electric|
|Bucyrus MT6300AC||Bucyrus International||2008||400 short tons (360 long tons; 360 t)||diesel-electric||
Firm was acquired by Caterpillar in 2010.
|Caterpillar 797||Caterpillar||1997||360 short tons (320 long tons; 330 t)||diesel-mechanical||The 797F model has an increased capacity of 400 short tons.|
|Komatsu 960E-1||Komatsu America Corp.||2008||360 short tons (320 long tons; 330 t)||diesel-electric|
|Belaz 75600||BelAZ||2005||350 short tons (310 long tons; 320 t)||diesel-electric|
|Terex 33-19 "Titan"||General Motors Diesel Division||1973||1||350 short tons (310 long tons; 320 t)||diesel-electric||Prototype, only 1 built|
|Komatsu 930E||Komatsu America Corp.||1995||2,100||320 short tons (290 long tons; 290 t)||diesel-electric||Number built as of September, 2018|
See also edit
- Off-Highway Trucks from Caterpillar 2009.
- "CATERPILLAR 775G OFF-HIGHWAY TRUCK". ConstructionEquipment.com. May 16, 2011. Retrieved September 18, 2015.
- Orleman 2000, p. 15.
- Rogan, Alexander (5 March 2013). "BelAZ to build 450-tonne dump truck in 2013". Archived from the original on 28 September 2013.
- "Rear-eject dump bodies". World Highways. January–February 2013. Retrieved 2014-09-15.
- "Our History". Philippi-Hagenbuch, Inc. Archived from the original on 27 November 2020. Retrieved 10 April 2021.
- Woof, Mike. "ADT versatility makes trucks a popular choice". Aggregates.
- Mike Woof. Ultra Haulers. MotorBooks International. pp. 125–. ISBN 978-1-61059-236-9.
- Australian Journal of Mining: AJM. General Magazine Company. January 2002.
- "Combination rear eject/end dump bodies for scrap ". Recycling Product News
- "Komatsu ADT with rear eject body - performs well at Namakwa Sands operation". Quarrying, October 2008.
- Moore, Paul. "Material Progress". InfoMining.
- Orleman, Eric C. (2000-11-10). Johnson, Paul (ed.). Building Giant Earthmovers. Motorbooks Colortech. United States of America: MBI Publishing Company. ISBN 978-0-7603-0640-6. Retrieved 2010-03-02.
The ultra-hauler class includes trucks with a capacity rating of 300 tons and above.
- "Off-Highway Trucks from Caterpillar". Caterpillar Website. Caterpillar Inc. 2009. Archived from the original on 2009-09-24. Retrieved 2009-10-21.
Developed specifically for high production mining and heavy-duty construction applications ...