Rio Tinto rights get strong demand

Rio, listed in both London and Australia, said it had acceptances for 96.97 percent of the new London stock.

The indebted miner is raising money to cut a $38 billion debt mountain it accumulated when it bought Canadian aluminium group Alcan at the top of the commodities market in 2007.

Rio's market value has slumped 64 percent in little over a year, partly due to the debt-funded Alcan buy. Rio also rejected an all-scrip takeover offer from BHP, triggering broad criticism of Rio management.

"People still view Rio as having very good assets, and don't want to be diluted. But you'd want the board to be considering what it was that led up to the Alcan purchase and try and improve the processes so that sort of thing doesn't happen again," Barker added.

Rio's Australian shares gained 1.4 percent on Thursday to A$52.32, outpacing a 0.4 percent rise on the benchmark S&P/ASX 200 index.

Rio offered 21 new shares for every 40 held, priced at a steeply discounted A$28.29 per Australian-listed share and 14 pounds per London-listed share. The London shares closed on Wednesday at 21.55 pounds.

(Editing by Ian Geoghegan)