When Vale launched a billion-dollar offer for Toronto-based nickel miner Inco Ltd. back in 2006, many analysts and industry executives believed it was a very ambitious move by the Brazilian miner to diversify its portfolio. Some also suggested it was an expensive acquisition—one that would be hard from which to turn a profit.

But Vale proved them wrong, and has since demonstrated that its diversification wouldn't stop in nickel.

Rio de Janeiro-based Vale, the world's largest iron ore producer, has spent the past few years expanding production in order to meet the increasing needs of the global steelmaking industry—mainly the Chinese—with minerals such as nickel, coal and iron ore.

The Brazilian miner late last year announced plans to invest $11 billion this year, the biggest annual investment program ever launched by the...