Mining giant Rio Tinto is speeding up the expansion of its iron ore operations in the Pilbara region of Western Australia.It is pumping in US$676m (£412m) to achieve capacity expansion to 333m tonnes a year in the first half of 2015, six months earlier than planned. The money will be used to develop port and rail infrastructure, Rio said."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 said. "We are taking the opportunity to bring forward the next phase of our major capacity expansion to reap the benefits early and at no additional cost."Rio Tinto began a five-year plan in 2010 to increase expansion in the Pilbara by 50%.---RG