Rio said it had been a "record breaking" period for the company, with first-half cash flow of $12.9 billion, a 31 percent premium on the previous corresponding period, and net profits of $7.587 billion.

The results, which included record underlying earnings before tax and other factors of $14.3 billion -- 27 percent higher than first-half 2010 -- came in slightly below market expectations.

"Conditions have remained favourable over the past six months due to strong Asian demand, although the volatile economic environment that we highlighted 18 months ago, continues to exist, driven by significant macro economic imbalances," said Rio chairman Jan du Plessis.

Chief executive Tom Albanese said volumes were lower in the half due to severe weather events in Australia but "we were able to take advantage of higher prices for our products," to the tune of $4.997 billion.

Currency movements, including the marked depreciation of the greenback against the Australian dollar, wiped $810 million off the bottom line.

Copyright AFP (Agence France-Presse), 2011