The miner said with ore processing now started, it will be progressively ramping up to a projected nameplate capacity of 1.5 million tonnes per year and achieving design-outlined recoveries, as well as meeting specifications for the metal concentrates.

"Reclaimed tailing from hydraulic mining operations are now being processed in the new flotation treatment facility," it said, adding that advancement of underground development has also exceeded plans for the third consecutive month, with 1.4 kilometres completed to date.

"In addition, preparation for the first processing campaign of high-grade underground ore is well advanced and will proceed following the current ramp-up programme."

Woodlawn is expected to produce, on average, 40,000t zinc, 10,000t copper, 12,000t lead, 900,000 ounces silver and 4,000 ounces gold annually over an initial mine life of 9.3 years. There is great potential for that to be extended via the conversion of high-grade underground resources.

Heron had an 18-month construction process to get to its wet commissioning milestone in March.

Woodlawn, which Heron owns 100% of, is located 250km south-west of Sydney and is Heron's primary focus.