The world’s largest copper mine, in Chile, is poised to expand under plans unveiled by its investment partners BHP Billiton and Rio Tinto.
The mining giants on Tuesday announced a total investment of $US4.5 billion ($A4.21 billion) for the expansion of the Escondida copper mine, south east of Antofagasta in Chile.
This includes contributions from Japanese minority joint venture partners, including the including Mitsubishi-controlled JECO Corporation.
The mine is BHP Billiton and Rio Tinto’s second copper joint venture, alongside their Resolution copper project in Arizona in the United States.
There is also their South African mineral sands joint venture via Richards Bay Minerals, which BHP Billiton earlier this month said it was exiting by selling its 37 per cent stake to Rio Tinto.
BHP Billiton has a 57.5 per cent interest in Escondida and operates the mine, while Rio holds a 30 per cent stake and the remainder is owned by the Japanese parties.
The expansion will involve the replacement of a concentrator at the mine with a new plant to enable access to higher-grade ore beneath the existing facilities, BHP Billiton and Rio Tinto said in statements.
That project would cost $US3.8 billion ($A3.55 billion), the companies said, with construction expected to begin this month and completion slated for the first half of calendar 2015.
The Escondida joint venture will also spend $US721 million ($A673.96 million) on a new leaching pad and mineral handling system, which is expected to maintain oxide leaching capacity at current levels after the existing heap-leach facility is exhausted in 2014.
Leaching is the process used to extract metals from ore.
BHP Billiton also announced a 25 per cent increase in ore reserves at Escondida after successful exploration programs.
BHP Billiton base metals president Peter Beaven said the company expected a substantial recovery in copper production at Escondida to more than 1.3 million tonnes per annum in the 2015 financial year.
“The success of our brownfield exploration program suggests there are sufficient resources at Escondida to sustain production at current levels for more than a century,” Mr Beaven said.
Grades have been falling at Escondida but output is expected to substantially increase once the higher-grade ore is accessed.
Strikes and wet weather also interrupted production at Escondida during the half year to December 31, BHP Billiton reported in its interim results last week.
BHP Billiton also on Tuesday announced it would re-start mining at its Pinto Valley copper and molybdenum operation in Arizona, with a $US195 million ($A182.28 million) investment.
The mine would have annual production capacity of about 60,000 tonnes of copper-in-concentrate, the company said.
