Haul truck



Haul trucks are off-road, heavy-duty dump trucks specifically engineered for use in high-production mining and exceptionally demanding construction environments. Most are dual axle; at least two examples of tri-axles were made in the 1970s. Haul trucks are denominated by their payload capacity, by weight (variously in tons, tonnes, and kg).

Description


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 ST to nearly 500 ST.

An example on the smaller end is the Caterpillar 775 (rated at 70 ST). Quarry operations (which produce payloads that have value) are typically employ smaller trucks than mining operations (such as removing undesirable overburden, an expense).

Haul trucks can generally be distinguished from standard dump trucks by:


 * Being far too large to travel legally on public roads
 * Having a dump body made of exceptionally strong steel plate that extends over the cab to protect it, angled upright at its end (or entirely) to aid in dumping; some are heated by exhaust gases to prevent loads from sticking or freezing to the bed;
 * Having a driver's cab narrower than its body;
 * No axle suspension;
 * Limited speed and operating range;
 * Special off-road only tires;
 * A ratio of dead weight to payload not exceeding 1:1.6

Most large haul trucks use some form of traction motors coupled to regenerative brakings for power, braking, or both.

Haul trucks are classified by:
 * Type of unloading (dump or rear-eject);
 * Direction of discharge (side, rear);
 * Type of body (hopper, platform, sliding hopper, sliding platform).

Ultra class


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 ST or greater. , the BelAZ 75710 has the highest payload capacity, 450 t.