Associated Press: The largest dump truck in the world, parked under a massive mechanical shovel, is waiting to transport 400 tons of oily sand at an open-pit mine in the northern reaches of Alberta. Each Caterpillar 797B heavy hauler – three stories high – carries the equivalent of 200 barrels of heavy oil worth $23,000 per haul at today’s prices. "It’s like sitting on your back porch and driving your house," said Todd Dahlman, the manager of Shell Canada’s Muskeg River open-pit …