6/23/2004: Biggest truck

[onetrack]

dar512 has it sussed. There has been a longstanding argument between big truck makers, as to whether to have Diesel Electric or Mechanical drive.
Caterpillar came out in favor of Mechanical drive for all their trucks, stating the Mechanical drive they build, was cheaper to build, and easier to maintain .. whilst many other manufacturers such as Liebherr chose Diesel Electric.

Caterpillar have lost out now, because of the weight penalty with Mechanical drive. A Diesel electric truck, when it gets to the large sizes, has a 30% weight saving over Mechanical drive. This weight saving is not available in the smaller size trucks .. in fact, with a small truck, Diesel electric has a weight penalty over Mechanical drive.

The change that has made all the difference, is the change to AC motors from DC motors.
DC motors were used in the dump trucks for a long time, because AC motors are more difficult to control .. and it was only the advent of modern electronics, that made using AC motors, viable.

Re the "fuel waste'' ... these trucks are highly efficient, in comparison to the amount of dirt shifted in relation to fuel cost .. the cost of earthmoving with these trucks runs to merely cents per tonne over many kilometres.
The cost of moving dirt has been coming down steadily over the decades, as technology increases .. this means cheaper end products for all.

Re the questions on how do you manage to drive a monster like this? They are, in fact, quite easy to drive .. to the extent that many women are operating them.
The controls are only a little different to an automatic car .. the major thing is getting used to the size of what you are driving .. which is no different to readjusting your thinking when you drive a bus instead of a car.

They do have very limited vision though, and the operators must exercise great care, as running over small vehicles presents a real hazard. Accordingly, it is against mine regulations to park with 20 metres (66') of any truck, unless the truck is shut down and maintenance or fueling is being carried out.

The operators are taught to drive them on simulators, much like jet simulators. These simulators are amazingly realistic, with the ability to programme in the minesite layout, on a panoramic wide screen.
The cabin is replicated exactly, the engine sounds are included, as are other smaller vehicles moving across your path, road signs, waste and ore stockpiles, the mine ramp, other equipment .. all the potential hazards of a standard minesite.
Safety in mining is given extremly high priority, and the safety levels on a minesite are 10 times higher than your average street .. and the low level of accidents reflect that.
However, occasionally things do go wrong, and accidents happen.

The biggest hazard is waste or ore stockpiles. Even though a low wall, or bund is kept in place around the edge of stockpiles, sometimes the soil slips without warning, when the truck is dumping, and the truck can roll off the dump.
The cabins are heavily reinforced and can withstand great impact. Seat belts are worn at all times, and if the truck rolls, you stand a very high chance of survival without major injury. The only fatalities that have happened in recent years are those where an operator did not wear their seatbelt.

Fire is another hazard that is taken care of with an on-board fire suppression system. At the first sign of fire, the extinguishers are activated automatically or by the operator, limiting any chance of a fire taking hold.