Rio Tinto Group, the world's second-largest mining company, said third-quarter iron ore output rose 6 per cent, more than analyst expectations, as it expands its operations in Australia.

Iron ore production increased to 52.6 million metric tons in the three months to September 30, from 49.8 million tons a year earlier, the London-based company said today in a statement.

Iron ore output from Australia's Pilbara region rose to a quarterly record, it said.

"Markets remain volatile, but our business is resilient and our operations are performing strongly, reflecting our consistent strategy of running large, long-life, cost- competitive operations," chief executive officer Tom Albanese said in the statement.

Iron ore prices have rebounded 30 percent since reaching a near three year low last month.

Rio Tinto this month said it's expanding its Australian iron ore operations, while delaying decisions on investments in other commodities.

Fortescue Metals Group said today it may resume developing its Kings iron ore deposit and reported a 26 per cent jump in quarterly iron ore shipments, topping analyst expectations.

Rio, the biggest exporter of the steelmaking raw material after Vale, fell 1.3 per cent to A$55.12 at the close in Sydney. The stock has declined 8.3 per cent this year.

"Iron ore projects in the Pilbara are offering returns far above other commodity projects," Myles Allsop, a London-based resources analyst with UBS AG said in an October 10 report following an investor briefing.

"Spend on Pilbara iron ore is the bulk of the capex and Tom Albanese made no apologies for spending in iron ore given its superior returns."

Bloomberg