Fortescue yesterday unveiled a 72 per cent increase in the Pilbara project's resource to 2.12 billion tonnes and said a feasibility study on the project should be completed by the end of March, reports The Australian Financial Review.

The North Star project, which has an average grade of 31.6 per cent iron, is similar in size and grade to the $US6 billion Sino Iron project being developed by CITIC Pacific.

Fortescue said North Star could produce between 20 million and 30 million tonnes of iron ore annually for a 20-year period.

In addition to North Star, Fortescue also owns a 65 per cent stake in the adjacent Glacier Valley project in a joint venture with Chinese steelmaker Baosteel.

Combined, the 3.2 billion tonnes of resources at North Star and Glacier Valley make for one of the 10 largest magnetite deposits in the world.

In December, Fortescue signed a land access agreement with the Njamal people covering North Star, creating a joint venture between the miner and the native title holders to run a mining operation in return for certainty of tenure over the ground.

Fortescue yesterday said any development of North Star, which is located 100 kilometres south of Port Hedland and within 25km of its existing railway line, would be non-recourse to its own balance sheet.