KCGM described the new UGD mill as the biggest change to gold processing, with the new 30 tonne per hour plant eliminating atmospheric stack emissions from the Gidji plant.

The project is part of KCGM’s $A98 million Emissions Reduction project.

KCGM acting general manager Ian Butler said installation of the UFG mill marked a significant transition in how sulphide gold concentrate from the Golden Mile would be processed in the future. 

“Golden Mile ore is unique, with most of the gold intricately bound in various sulphide minerals such as pyrite,” he said.

“Roasting is still the most effective method of extracting gold, however as part of KCGM’s long-term commitment to continuous improvement, we have looked at alternative forms of concentrate treatment since the 1990s.” 

KCGM was the first company in the Australian gold industry to adopt the UFG IsaMill when a 10tph mill was installed at Gidji in 2000, followed by a second at the Fimiston plant in 2002.

“Our UFG mills use very small ceramic balls (2.5mm) to grind the concentrate and expose the trapped gold to the downstream cyanide-leaching process,” Butler said.

“The UFG mills have now proven that they are a viable alternative for treating gold concentrate, allowing KCGM to fully replace roasting at the Gidji processing plant.” 

Fimiston concentrate will continue to be trucked to Gidji for processing.

Northern Star Resources now owns the only remaining roaster in the Goldfields at its Kalgoorlie operations.

There were 88 roasters along the Golden Mile in the early 1900s.

“KCGM has always been committed to reducing the impacts of our operations on near neighbours,” Butler said. 

“KCGM is very aware that the ongoing support of the community and government for our operations is essential to maintaining our licence to operate and ensuring our long term future.” 

KCGM is a 50:50 joint venture between North American majors Newmont Mining and Barrick Gold, though Newmont recently took over operating responsibility of the division.