Rio Tinto ramps up Australian expansion in a scramble to fill steel supply gap

Rio Tinto will speed up its $14.8 billion iron ore expansion project in Australia by six months, joining other miners in hurrying production to fill a supply gap for the steel-making commodity.

Big miners are betting China's demand for raw materials to fuel industrial expansion will continue to surge, despite mounting fears of slowing economic growth as Beijing clamps down on bank lending.

Rio expects to expand its iron ore production by 50 percent to 333 million tonnes a year by the first half of 2015, six months ahead of its earlier target.

"The demand outlook continues to be strong with supply lagging elsewhere in the industry and we are seeing new supplies proving slower to materialise than predicted," Rio Tinto iron ore division head Sam Walsh said in a statement.

Rio Tinto is not alone in beefing up in iron ore.

From the Australian outback to West Africa to South and North America, more mining companies are pegging new iron ore mines, many with the help of Chinese seed money.

AngloAmerican expects to nearly double iron ore production to around 80 million tonnes by 2014 as it digs new mines in Brazil and South Africa.

Fortescue Metals Group has said it plans to bring forward its Australian iron ore production target of 155 million tonnes a year by up to 12 months, while Vale of Brazil wants to push output up 50 percent to 450 million tonnes, also by the start of 2015.