Mining majors Rio Tinto and BHP Billiton are set to jointly invest over $3bn for the construction of a new seawater desalination facility in order to sustain operations at Escondida copper mine in Chile.

Rio has approved $1.03bn for its 30% stake in the project, while BHP will provide $1.97bn.

The 2,500l per second project will provide continued water supply to Escondida’s new OGP1 copper concentrator approved in February 2012, and reduce the mine’s dependence on the region’s aquifers.

The project will include two pipelines, four high pressure pump stations, a reservoir at the mine site and high voltage infrastructure to support the system.

Construction of the project will begin in July 2013 with commissioning scheduled in 2017.

BHP Billiton Copper president Peter Beaven said obtaining a sustainable water supply in the Atacama Desert is a priority for all copper producers in Chile.

"The new desalination facility will minimise our reliance on the region’s aquifers, which will help us to meet our environmental commitments and enable us to achieve our long-term business strategy," Beaven added.

Escondida, located 3,100m above sea level, 170km South-East of the City of Antofagasta, is owned by BHP Billiton (57.5%), Rio Tinto (30%), JECO Corporation (10%) and JECO 2 Ltd (2.5%). BHP operates the Escondida mine.