Copper Begets Copper
They are by far the largest off- or on-road trucks in the world. They can haul as much as 400 tons of ore from open-pit mines, including copper mines, to smelters. Yet these house-size machines, which cost $3 million-plus each, couldn't perform their Herculean chores without copper.
Three of the four brands of mining trucks-- those from Komatsu, Liebherr and Terex-depend on diesel-electric designs, much like the latest diesel-electric locomotives (Copper Topics No. 84). Big diesel engines that drive generators supply power to electric motors in the axles. This requires tons of copper per truck. For instance, there's 3,575 pounds of copper in just the AC generators and AC induction drive motors of each of Liebherr's T 282 models.
The drive motors, like all the largest induction motors, are made with copper rotors. Although Caterpillar's mining trucks have direct mechanical drives, it still takes a lot of copper to build them. According to a company spokesman, there is 2.5 miles of copper wiring in each of Caterpillar's new Model 797 trucks. To weld the frames on a 797 requires an additional 500 pounds of copper welding wire.
All these trucks also depend on big radiators with copper tubing to keep their water-cooled diesels from overheating. The radiator on the largest Terex mining truck, model MT5500, contains approximately 2,500 pounds of copper tube and fins, according to engineer Larry J. Vargus. It is made by L&M Radiator, which also makes radiators for Komatsu and Liebherr. Even more copper is utilized to provide air-conditioning to the truck's operator compartments.
To comprehend the outsize proportions of these machines, here are some statistics on the Caterpillar 797 truck:
- Capacity: 360+ tons
- Weight empty: 288 tons
- Length: 48 feet
- Height: 23 feet
- Width: 30 feet
- Horsepower: 3,400
- Tires: 14 feet in diameter at 10,000 pounds each
- Paint required: 90 gallons
- Lines of code for its 7 on-board computers: 1.25 million
In addition to these ore-movers, there are other huge machines, such as steam shovels and portable conveyors, employed in both open-pit and deep mining. All require lots of copper to perform their demanding jobs.