The giant miner BHP Billiton announced this week a 129% increase in the mineral resource at and around Chile’s Escondida, the world's biggest copper mine.
If it can convert this to the more certain category of reserves -- meaning they are economic to mine -- the 19.5 billion tons of ore resources the Escondida region contains should yield about 107 million tons of copper.
At current copper prices, that represents just over one trillion dollars of revenue.
The previous Escondida resource, announced at the end of 2009-10, was 8.5 billion tons, for 52.3 million tons of contained copper.
At a Barcelona conference in May, chief executive Marius Kloppers said Escondida was one of five areas around the globe where BHP could expect more than 100 years of production, based on potential mineralisation. That term effectively meant the deposits had not been drilled or analysed to the point where they could be labelled resources or reserves under Australian stock market rules.
This week BHP backed up its claim that Escondida could hold a resource more than double its previous estimate. Escondida produced about 680,000 tons of copper in 2010-11.
This significant increase follows an extensive, four-year, 381 million dollars brown-field exploration program and entrenches Escondida's position as the world's leading copper mine for decades to come, the company.
BHP owns 57.5% of Escondida, while Rio Tinto has 30%.
Just over half the new resource tons come from the first reporting of a resource at the Pampa Escondida deposit, a deep discovery that sits between the Escondida and Escondida Norte mines.
Almost all the rest of the extra resource is from Escondida itself, apart from a relatively small, 175 million ton resource declared at a deposit named Pinta Verde, 4km north of Escondida.
Escondida grades and production have fallen in recent years. In April, BHP revealed planned improvements at Escondida, starting with a 554 million dollars plan to access higher-grade ore.