Corporación Nacional del Cobre de Chile (Codelco) will invest $875m in initial works to transform Chuquicamata open-pit mine into an underground operation.

Codelco will carry out initial works on reserves buried under the deposit, which are expected to be completed in five years.

Chuquicamata mine has estimated underground copper and molybdenum reserves of 1.7 billion tonnes, and the new underground operation is expected to produce 340,000t of copper.

Codelco is planning to spend about $17.5bn to increase the copper output to 1.8Mt by 2014 and to a further 2.1Mt by 2020.

The overhauling is scheduled to be completed in the first half of 2019, reports Reuters.