Mining is a long-term business and timescales can run into decades. The period from initial exploration to the start of production can exceed 10 years and, depending on the nature of the project and the market conditions, it may take more than five years of operation to recoup the initial investment.

For geological reasons, copper deposits frequently have highergrade material nearer the surface and therefore grade declines with depth. This means that unless action is taken, such as an expansion, copper production declines as a mine gets older. Also, as an open pit gets deeper, haulage distances and rock hardness increase, and this, combined with the declining grade, leads to higher unit costs. Large long-life mines will have several expansions during their lives. The current expansion at our 20-yearold Los Pelambres mine is its fourth.