Aluminum Corporation of China (Chinalco) and Alcoa have bought a 9% share of Rio Tinto worth US$14.5 billion, the Wall Street Journal reported. Chinalco and Alcoa’s investment represents 12% of Rio Tinto’s London shares and 9% of the company if its Australian shares are included. The two aluminum companies said they do not currently intend to bid for the rest of Rio Tinto, though they reserve the right to do so if circumstances change. The mining company BHP Billiton has been trying to take over Rio Tinto since November. Chinalco must now agree to any bid by BHP Billiton, which has until February 6 to make another offer for Rio Tinto.