The German-made 3MW IsaMill will give the Woodlawn processing facility critical fine grinding capabilities to reduce flotation feed to a size of 30 microns. In commercial use for 18 years, the unit is most effective for zinc, copper and lead sulphides.

Heron managing director Wayne Taylor, calling the IsaMill an integral component of Woodlawn, said its arrival is its technological "step change".

"This technology only became available after Woodlawn's former operations [closed in 1998], and it enables Heron to reduce the grind size to provide the most effective mineral liberation, allowing for the highest recoveries to our base metal concentrates," he said.

Heron said that its engineering, procurement and construction (EPC) contractor Sedgman is continuing to make good progress with the project's construction; at the end of June, work was 62% complete. Woodlawn remains on schedule for the start of commissioning in the December quarter of the year.

The Sydney-based producer, which owns 100% of Woodlawn, is targeting an early 2019 production start.