Declining mineral content, the need to preserve the environment, and technological advances are causing big mining companies to turn back to underground mining in what is a rising trend in Chile and around the world, experts say.
This South American country possesses the world’s largest underground copper deposit, which is owned by the state National Copper Corporation of Chile (CODELCO) and has been mined since 1905.
The El Teniente Division mine, as it is formally named, was responsible for 25 percent of CODELCO’s total production of 1.75 million tonnes of fine copper in 2012.
Some 137,000 tonnes a day are extracted from El Teniente’s Sector 8, which is currently operating.
But the deposit under the Andes mountain range, 150 km south of Santiago, with 3,000 km of underground tunnels, has only enough copper to last until 2025 at the present rate of extraction.
As a solution, CODELCO is developing its New Mine Level project, which is expected to start operations in 2017 and will access 2.02 billion tonnes of reserves at greater depth, at an altitude of 1,880 metres above sea level, 100 metres below the current mining level.
The project will extend the productive life of the mine for another 50 years. It involves the use of cutting-edge technology and an investment of 3.3 billion dollars, similar to the amount spent throughout the history of this emblematic mine.
Chile’s economy depends on copper, which was nationalised in 1971. In 2012, CODELCO made a profit of 7.5 billion dollars, the third-highest level in its history, thanks to output of 5.45 million tonnes.
Chile is the world’s largest producer and exporter of copper, which accounted for 12 percent of Chile’s GDP last year, and 53.9 percent of export revenue.
The operational costs for an underground mine are not necessarily higher than for open pit mines.
Source: Marianela Jarroud | IPS News