Engineers are building four huge floors underneath the pit, in addition to the tunnels, to extract 340,000 tons of copper a year from beneath the ground. The trucks will be replaced by conveyer belts that will carry ore to the grinding machines and the smelter.Alvaro Aliaga, general manager of Chuquicamata's underground project, said the project will put Chile on "the vanguard of global mining." All over the world, the race for resources is forcing countries to spend more and drill deeper than they ever have before. Energy companies in the United States are using hydraulic fracturing to tap huge gas and oil reserves from Pennsylvania to Alaska. Argentina is preparing to explode rock to get unconventional oil and gas in Patagonia. Brazil has pioneered deep-water drilling techniques in the Atlantic. These long-term, multibillion-dollar projects are creating technological feats and opportunities for new industries unseen since the U.S. space race. "This resembles some of the projects in Argentina and Brazil in terms of its magnitude and the challenge they represent for engineering because they're works of a tremendous scope and with a huge impact on the national economy," said Aliaga. Work has already begun on the tunnels at the mine, which is 745 miles (1,200 kilometers) north of Santiago in the world's driest desert. Perforating the rock with a machine that looks like a giant yellow praying mantis, engineers lay explosives that blast through the cavernous walls for ventilation shafts. "Two of these five tunnels are going to be built to inject clean air and make sure the dirty one comes out," Maria Cristina Vallejos, the only female miner at Chuquicamata, said as she took cover from a nearby blast. "They'll give us the best environmental conditions for the underground work." Inside one of the tunnels, a bulldozer removed rock and dirt while miners installed a steel mesh to avoid a cave-in, advancing at a painstaking pace of about 13 feet (4 meters) per day. The main tunnel will eventually stretch for more than 4.5 miles (7.5 kilometers).