Rio Tinto is in the process of developing plans with its advisers at Morgan Stanley to raise up to $380.8 million (GBP 250 million) through a separate listing of the company's diamond division on the London Stock Exchange (LSE).

Sources close to the company told Sky News that a flotation of the miner's diamond business seemed increasingly likely after efforts to obtain a compelling offer from an outside buyer were unsuccessful.

The diamond unit listing, code named Project Aurora, could take place as soon as the third quarter and will involve raising funds through the sale of new shares in the business. However, the share flotation could be abandoned if the company is able to secure a sufficient, high offer from a bidder.

Some analysts estimate the company's diamond business is worth as much as $5 billion, according to Sky News. Rio Tinto's diamond unit includes the Argyle mine in Western Australia famous for its rare pink diamonds, as well as a 78 percent stake in the Murowa mine in Zimbabwe and the Bunder diamond deposit in India.

The company also owns a 60 percent stake in the Diavik mine in Canada, where Dominion Diamond Corporation owns the remaining 40 percent and is ‎reportedly interested in Rio Tinto’s stake. Rio Tinto 's diamond production fell 4 percent year on year to 3.24 million carats for the first quarter that ended on March 31.