Net profit for the six months to June 30 climbed 112.5 per cent on the corresponding period to $US6.91 billion ($A8.01 billion), underpinned by higher prices and production, particularly from iron ore.
Underlying profit, or earnings before interest and tax (EBIT), rose 55 per cent to $US5.47 billion ($A6.34 billion) and was broadly in line with analysts' forecasts.
Rio Tinto is reaping the rewards from the rapid urbanisation of China and other developing nations that has been driving greater demand for commodities and rising commodity prices for the past seven years.
"We expect prices for Rio Tinto's major commodities to remain substantially above the long-run trend in 2009," chairman Paul Skinner told reporters.
Shares in Rio Tinto, which is the focus of a hostile $US150 billion ($A173.93 billion) takeover proposal from rival BHP Billiton Ltd, gained $1.76, or 1.44 per cent to $124.06.
Earnings before interest, taxes, depreciation and amortisation (EBITDA) for the half climbed 73 per cent to $US11.41 billion ($A13.23 billion), with Rio Tinto's iron ore division the biggest earner for the group.
Underlying earnings for the iron ore division grew 161.8 per cent to $US2.88 billion ($A3.34 billion).
"The outlook for iron ore remains excellent," Rio Tinto chief executive Tom Albanese told reporters on a conference call.
He said Chinese demand for aluminium continued to grow strongly and the outlook for coal demand in Asia remained "excellent".
Rio Tinto, the world's second largest aluminium producer, posted a 145 per cent increase in underlying earnings from its aluminium division to $US995 million ($A1.15 billion) after its Alcan acquisition last year.
Albanese said the company was on track to deliver annual synergies after tax through the Alcan purchase of $US1.1 billion ($A1.28 billion) from the end of 2009, higher than the initial estimate of $US600 million ($A695.73 million).
Underlying earnings for Rio Tinto's energy division, which comprises its coal and uranium assets, grew 83.5 per cent to $US679 million ($A787.34 million).
"It was a great result and it keeps the pressure on BHP as it continues the chase," Fat Prophets analyst Gavin Wendt said.
"The only black spot was that copper earnings were down slightly after they had some mining issues during the year."
The copper and diamonds division suffered a drop in earnings to $US1.69 billion ($A1.96 billion), down from $US1.91 billion ($A2.21 billion) in the previous corresponding period.
The company said increased energy costs reduced earnings by $US132 million ($A153.06 million), with higher freight, contractor, maintenance and input costs experienced throughout the group.
Rio Tinto said it was on track to divest $US10 billion ($A11.6 billion) of assets this year to help pay down debt after its $US38.1 billion ($A44.18 billion) Alcan purchase.
"Rio Tinto is in great shape, and is getting stronger," Albanese said.
The company declared a final dividend of 68 US cents per share, up 31 per cent on the previous half.
The federal government this week cleared the way for Aluminium Corporation of China Ltd (Chinalco) to increase its nine per cent stake in the dual-listed Rio Tinto to 11 per cent.
