Caterpillar 797

The Caterpillar 797 mining truck was the largest of its kind in the world until 2001. Brought into operation in 2000, it has a payload capacity of 360 tons. The Cat 797 is powered by a 24 cylinder V24 quad-turbo diesel engine that produces an amazing 3,400 horsepower. The truck is 23 feet from the road to the top of truck bed, and almost 50 feet tall when the bed is raised for dumping. The total Length of the truck is 47.5 feet.

Eight onboard computers monitor oil pressure, transmission torque, engine performance and tire temperature. The Caterpillar 797 sells for $3.4 million; the 13 foot tall Michelin tires were especially designed for the 797, and cost about $30,000 each.

When a new 797 is delivered, it arrives in pieces aboard 12 semis, including an 850 gallon (or optional 1800 gallon) fuel tank.

With a full load, the 797 can move as fast as 40 mph on level ground. Behind each wheel is a pack of 42-inch brake discs ... 10 each in front, 15 per corner in the back. Dissipating that energy is a computer controlled brake-cooling system that pumps oil -- up to 1160 gallons of it per minute -- through multiple coolers and then through the discs. These brakes work!

The truck uses fuel in huge amounts ... an average of 65 gallons/hr ... with a fuel economy rating of 0.3 mpg. With such huge costs involved, the vehicle is usually run 24 hours per day, 365 days per year, stopping only for regularly scheduled maintenance.

For maximum efficiency, mining truck volume must be a multiple of mining shovel capacity. Cat built the 360 ton capacity 797 specifically to handle the 90-ton loads carried by the industry's biggest shovels; four scoops and the truck is full. But P&H Mining Equipment of Milwaukee recently debuted a "dipper" capable of snatching ore in 100-ton bites, which creates a problem in filling the 360-ton-capacity pickup. New models are in the works!