AuStar Gold has announced the re-commencement of gold processing at its Morning Star process plant in Victoria, Australia, and, at the same time, signed an agreement with Gekko Systems to acquire a custom-made intense leach reactor for the processing of residual sulphide/gold concentrate.
The agreement with Gekko, which should enable increased overall gold recoveries from the process plant, was the last remaining processing hurdle for AuStar, given the small component of non-free milling gold present in its ore, to maximise commercial gold recoveries, it said.
The AuStar Gold process plant at the Morning Star mine site uses standard gravity methods (enhanced by recent investment in a high-speed centrifugal concentrator to recover gold from the Morning Star and Rose of Denmark ores.
“Through the gravity process, the gold room captures approximately 65% to 75% of the gold directly to bullion, with an additional 15% of fine free gold residing in the middlings as concentrate and up to 10% of fine free gold in the gold room table rejects,” AuStar said.
The material containing the fine free gold (concentrate) not captured directly into bullion at the Morning Star plant is to be treated by Gekko Systems offsite, with expected recoveries in these two fractions of approximately 95% of the contained gold, the company said. This is expected to lift total gold recovered and sold from ore supplied to the mill to better than 90%, AuStar added.
Meanwhile, a high-speed centrifugal concentrator has been purchased to replace the smaller, hired unit presently located in the process plant which produces concentrate to be provided to Gekko. This larger unit is being installed in March.
A custom-made intense leach reactor is under construction at Gekko’s Ballarat facility, designed to suit Morning Star concentrate, and will be operational in early April, the company concluded.
Just last month, AuStar confirmed it would re-start mining activity at the historic Morning Star and Rose of Denmark mines in February, with processing at the Morning Star gravity processing plant expected before the end of that month.
Morning Star is a proven past operator, with 830,000 oz of gold at 26.5 g/t Au previously produced.