China-based Citic Group has flagged a $US1.4 billion to $US1.8 billion impairment at its Sino Iron magnetite project in the Pilbara as a result of the falling value of iron ore.

China-based Citic Group has flagged a $US1.4 billion to $US1.8 billion impairment at its Sino Iron magnetite project in the Pilbara as a result of the falling value of iron ore.