Resource giant Rio Tinto Ltd (ASX:RIO) announced on Monday it is midway through a share buyback program designed to simplify its dual-listed structure and improve cash management.

The miner early last month agreed in principle to reacquire all of the Rio Tinto Ltd shares held by Tinto Holdings, a wholly owned subsidiary of its London Stock Exchange-listed Rio Tinto plc.

The buy-back would take place in two tranches and valued at around $9.2billion.

It is part of an "internal capital management programme designed to distribute capital within the Rio Tinto dual-listed company structure in the most efficient way."

The group said that removal of cross-shareholding from the Australian-listed and the UK-listed part of the group would also achieve a simpler corporate structure.

Rio Tinto in August completed the first portion of the buyback with the purchase of 150.43 million of its shares from Tinto Holdings at $69.27 each share.

"Those shares have subsequently been cancelled," Rio Tinto said.

"The remaining 20,635,155 ordinary share are likely to be bought back later this month.

"It should be noted these internal capital management transactions do not affect the number of shares held by public shareholders.

"The shares will be cancelled after the buy-back is completed."

Shares in Rio Tinto ended $1.21 or 1.64 per cent higher at $75.