Sedgman, the Queensland engineering group acquired by CIMIC, has angered one of its newest clients, Heron Resources, by claiming it should be paid 50 per cent more than what it was due to receive under a fixed price contract.

Heron Resources chief executive Wayne Taylor told The Australian Financial Review he was "surprised and disappointed" that Sedgman was continuing to pursue a $53 million claim on a $109 million contract to build a zinc-copper crushing and processing facility at its Woodlawn project in southern NSW.