Codelco submitted an environmental impact assessment of its plans to revamp the Salvador copper project in Chile, which will extend the mine's life by 40 years, Reuters reported Oct. 16.

The mine, which has been operating since 1959, is expected to run out of resources in 2021 under its current conditions. Codelco plans to convert the underground operation to an open cast project.

"Through various drilling campaigns, we have identified copper reserves of 900 million tonnes of ore, with average ore grades of 0.59%, which would prolong the useful life of the division and its operational continuity for at least four decades," CEO Nelson Pizarro said in a statement to Reuters.

The overhaul requires an investment of about US$1 billion and will increase production to about 90,000 tonnes of copper once it is completed in 2021. In 2017, Salvador produced 62,000 tonnes of copper.