Codelco’s board of directors has approved the development of the Chuquicamata underground mine below the current open pit – one of the largest copper mines in the world which is nearly 100 years old. This project, expected to cost in excess of $4 billion, will provide a block cave mine accessing some 1,7oo Mt of copper ore (with byproduct molybdenum) for an additional 43 years, starting from 2019.Chuquicamata is Codelco’s most important division, accounting for over 40% of the state-owned company’s total production.Codelco is now expected to be the mining company making the highest investments of any around the world during the next five years. It has been said that Codelco’s current one investment plan is the most ambitious in its whole history, requiring $20 billion until 2020.According to a company document submitted to the Congress in October, the cost of the total structural projects portfolio reaches an updated figure between $26,218 million and $29,718 million, including Underground Chuquicamata, RT Súlfuros, Rajo Inca, Andina 244 and others on the list.So, while other companies defer investment, Codelco is forging ahead. It is a slightly different case in that much of this investment is required to bring into production resources at old operations and because Codelco needs to do this to maintain its position in the copper market. “The thing is that every structural investment came together in the same time range, not allowing us to a required gradualness”, says Francisco Orrego, Freedom and Development Counsellor and ex Sub Secretary of Mining.The Chuquicamata underground project has been the subject of many years of planning and analysis.