CERRO LINDO - Vast mines in Peru and Chile that supply the world with crucial metals have started to pump water from the Pacific Ocean high into the Andes Mountains because of chronic water shortages exacerbated by climate change.
Tapping seawater allows miners to avoid relying on unpredictable rivers, which may run dry as glaciers melt, and avert clashes with farmers who draw their water from creeks in poor mountain villages.
"Water always generates conflicts between mines and farmers, so this is a good alternative because the source is limitless," said German Arce, who runs Peru's newest big mine, Cerro Lindo, owned by Peruvian miner Milpo. Ocean water is free, except for transportation and treatment.
Cerro Lindo relies entirely on sea water, filtered in a desalination plant and sent 6,000 feet (1,800 m) into the barren Andes in a thick green hose to the mine; its zinc, copper and lead refinery; and 700 workers who live there.
In Chile, Antofagasta Minerals soon will open the $1.5 billion Esperanza gold and copper mine. Like Cerro Lindo in Peru, it will be the country's first mine totally dependent on the sea.
The Esperanza project, set in the Atacama, one of the world's driest deserts, will pump sea water through 90 miles (145 km) of pipe to an altitude of 7,545 feet (2,300 meters).
The average mine requires millions of gallons of water during the course of its life, some 40 years, making access to reliable water increasingly crucial as global warming looms and cities grow.
More mines near the desert coasts of Chile and Peru plan to install desalination plants soon. Costs of the elaborate filtration systems have fallen over the last decade, while lofty global metals prices, boosted by demand from fast-growing Asia, may keep profits high for years to come.
Engineers in Peru from Southern Copper, a major metals producer, and Mitsui Mining & Smelting Co's 5706.TK1 Santa Luisa mine have inspected Cerro Lindo's sea water system as they plan for the future, Arce said.
Chile's Escondida mine, the world's biggest copper mine, may expand a desalination system it installed years ago, said a spokesman at BHP Billiton, the mine's owner.
"It's working really well and we are thinking of expanding it," he said. The existing plant supplies a quarter of all water at the mine.
Mining drives the Peruvian and Chilean economies, and is chiefly responsible for their exports. But conflicts over water, especially in Peru, where they often turn violent, have delayed billions of dollars of investments in new mines.
Poor residents in Peruvian mountain towns, afraid of losing access to fresh water, have delayed Zijin Mining Group of China's $1.4 billion Rio Blanco copper project and Anglo American's Quellaveco copper project.
Strident communities concerned about pollution have also forced companies to scrap plans for new mines, including Newmont's Cerro Quilish gold project, and the Tambo Grande gold project of a small Canadian company.
"The scarcity of water will cause economic conflict - it already has in parts of Peru, and it will affect the development of industry," said Jorge Alvarez Lam, climate change specialist with the Peruvian government.