The truck runs on a diesel-electric hybrid power system, and it has been engineered to carry a high payload with a lighter-than-average structural frame. It may sound like an ad for the latest “green” pickup, but this truck consumes hundreds of gallons of fuel per hour, and its payload is measured in the hundreds of tonnes.

In an industry in which productivity and cost-per-tonne are everything, the designers of Liebherr’s prototype TI-274 mining truck always are looking for a little more efficiency. The truck currently is being put through its paces at Liebherr’s testing grounds near Emporia, Va., and, depending on its performance, may form the basis for an expanded TI line of super-sized mining trucks.

Diesel-electric hybrid power systems are nothing new in Liebherr’s mining trucks. A diesel engine drives an alternator, and an electronic control system distributes power as needed. On the TI-274, each wheel has its own electric motor with a planetary drive, allowing for independent control of the wheels. Liebherr’s diesel-electric system differentiates the German firm’s trucks from the mechanically driven machines of Caterpillar, which controls most of the U.S. market.

Most mining trucks place the payload weight onto the frame, but the TI-274’s dump body connects at four points directly over the wheels. “The frame is not as heavy as in a conventional design,” says Cort Reiser, vice president of manufacturing, Liebherr Mining Equipment. “We’re taking that weight from the dump body and transmitting those forces right through to the wheels.”

“The limitation of building a bigger truck is the tires: The tire load becomes the gross vehicle weight,” says Bernd Vorhoelter, executive vice president, Liebherr Mining Equipment. “With the TI concept, we have a chance to push against this limit a little bit further.”

“We may not even introduce this truck as a 290-tonne class,” says Francis G. Wickert, general manager for product management and marketing, Liebherr Mining Equipment. “We could take the TI concept and maybe go to a 500-tonne truck. If you lower the EVW [empty vehicle weight], you increase the payload. The TI is the best chance to get our EVW as low as possible.”