China weighed in to the bidding battle for the world's mineral deposits yesterday when it launched the largest-ever dawn raid to snap up a 9 per cent stake in Rio Tinto, the mining giant at the centre of a takeover battle.

Chinalco, a state-owned mining company, in a joint exercise with Alcoa, the US aluminium group, spent $14bn in a move designed to block a planned $119bn takeover bid from rival miner BHP -Billiton.