Global miner Rio Tinto is negotiating with one of two major shareholders in Riversdale Mining to try and save its near $4 billion offer to secure a majority stake in the Africa-focused miner.

Rio Tinto had launched a $3.9 billion, sweetened takeover bid for Riversdale, conditional on at least 50% acceptances, but has so far secured only about 41%.

Rio Tinto's lawyer said in a letter released to the Australian Securities Exchange yesterday that Rio "genuinely believes that an outcome of those discussions is likely to emerge during the course of this morning". The letter was released by Riversdale.

No update on these talks was issued yesterday, indicating that they may have failed.

Rio however released a late statement after trading had ended which said that the company had