Maintenance foreman Gary Frost inspects huge dump trucks before they start the day at Barrick's Ruby Hill Mine outside Eureka, Nev., in 2006. They're definitely big, but these aren't the biggest mining trucks in use. See more pictures of trucks AP Photo /Douglas C. Pizac

The world's biggest truck isn't a Ford F-450 Crew Cab pickup truck, or even a Mack truck with a double trailer. The biggest trucks in the world are used in mining, and perhaps calling them big is an understatement -- these trucks are truly enormous.

The giant dump trucks used to haul heavy metal ores out of mining pits weigh in the neighborhood of one million pounds (453,592 kilograms) and can carry and dump more than 300 tons (300,000 kilograms) of material in the back. Where a Honda Fit has 117 horsepower and a Jaguar XF has 300 horsepower, these mining trucks have about 3,000 horsepower available for moving all that mass.



Mining trucks stand more than 20 feet (6.1 meters) tall -- the driver could climb from his cab into an open window on the second floor of an average building. And they're nearly fifty feet long, too, about the same length as an adult humpback whale.

But there's more than one manufacturer building these monsters, and the trucks are relatively close in size, so this is going to be a numbers game to determine which one is truly the largest. Here's the criteria used to determine which of five contenders will be crowned the biggest truck in the world:

Height: Measured from the ground to the highest point when the bed is level

Length: Measured from the very front to the very back when the bed is level

Gross Vehicle Weight (GVW): The total vehicle weight plus its heaviest load

Payload: The maximum weight that the truck can carry in the bed

Engine: Measured in maximum available horsepower

Keeping these five criteria in mind, check out the stats on the next page for the top five contenders -- all hoping to be named the biggest truck in the world.