Rio Tinto may achieve 50% control of Riversdale

RIO Tinto's 3 per cent increase in its bid for coal explorer Riversdale Mining should push it close to achieving its aim of 50 per cent control by the March 23 deadline.

Rio Tinto raised its offer price by 3 percent to A$16.50 per share on Thursday and extended the offer period for the third time, to April 1, but said the new offer was its final one if there were no competing offers.

Global miner Rio Tinto raised its offer for Mozambique-focused coal miner Riversdale Mining to $3.9 billion in a final bid to woo key shareholders who have held up the deal and gain control of coveted coal assets.

Tata Steel and CSN have both said they are mainly interested in securing coking coal from Riversdale. Tata, which already has a stake in Riversdale's Benga coking coal project in Mozambique, has said it was talking to Rio about a range of options.

CSN has not publicly revealed its intention over the Riversdale stake or about its possible talks with Rio Tinto.

Analysts said the two companies would probably like to see Rio Tinto, with deeper pockets and more technological skills than Riversdale, developing Riversdale's Mozambique mines and infrastructure.

Tata owns 27 per cent and Brazilian iron ore miner CSN is sitting on 19 per cent, with both supporting Rio as the operator of the Mozambique mines and seeking offtake agreements.

One argument suggests if Rio gets 43 per cent, then Tata will tip in 7 per cent to give Rio control while also maintaining a stake to balance that of CSN.

Riversdale was suspended after the bid increase with the stock price at $15.06, well below the $16.50 bid price, which is conditional on Rio getting over 50 per cent.