Mr Tom Albanese CEO of Rio Tinto while speaking to investors in Australia on Sunday, declined to put a value on Rio, but reiterated the company's stance that the all share offer did not recognize the miner's future prospects.

Mr Albanese told Australian Broadcasting Corp television that "We have seen the market move well past the BHP proposal, which we rejected. It is basically saying that, yes, we agree it is worth a lot more.”

Mr Albanese said that the BHP proposal also did not recognize that most of the synergies in a merged group would come from Rio, while Rio's iron ore business was growing faster than BHP's. He said "We have more mineral tenement, we have more operating mines, we have more mineralization, and we certainly have more infrastructure.”

Rio Tinto has rebuffed the offer of three BHP Billiton shares for every Rio Tinto share and Rio shares are currently trading at about a 17% premium to the offer.