Rio Tinto is a small producer of nickel, its output coming from a mine in Brazil due to close in 2005, and a smelter in Zimbabwe. Nickel is used in the production of special steels, notably stainless steel, and in so called superalloys. Over the past decade, world demand for nickel has grown at around 3.5 per cent a year, with a key driver being the use of stainless steel in developing countries