BGC signed a contract with John Holland this week to secure the work, which involves delivery of more than one million tonnes of ballast from its Elazac quarry near Port Hedland.

BGC CEO Greg Heylen said he believed the company's successful delivery of ballast to the adjacent Fortescue Metals Group and BHP Billiton rail lines over several years had been a factor in gaining the new work.

"This contract is the third award BGC has received for Roy Hill, and we are delighted to extend our participation in a project of this scale and significance," he said.

"Pleasingly, we continue to build the strength of our order book, underpinning our long-term financial stability."

In September the company was awarded a $420 million contract to complete the civil earthworks, concrete works, and general infrastructure for the port component of Roy Hill.

This was preceded by a $120 million contract to build the mine's internal roads and aerodrome, awarded in April 2012.

Roy Hill is about 277km south of Port Hedland in the Pilbara and is scheduled to start exporting iron ore in September 2015.

The rail line is being developed by Hancock Prospecting and a consortium of minority partners based in Asia.