Chilean state copper producer Codelco's Chuquicamata division used to be the world's largest red metal operation, producing close to 1Mt/y of fine copper. Codelco is currently developing a US$3.83bn project to convert the open pit Chuquicamata mine into an underground operation. Construction will take up to eight years and operations are scheduled to start by end-2019. The new operation will have a processing capacity of 140,000t/d for production of up to 340,000t/y of fine copper and more than 18,000t/y of molybdenum at full capacity, which is expected to be reached after a nine-year ramp-up. The transformation of Chuquicamata into an underground operation is the result of the depletion of profitable reserves at the open pit, which has become too large, increasing mining and transportation costs.