An eagerly awaited report into the provision of supply to an acid-hungry mining industry in North West Queensland is ‘on its way to my desk’.

So said Resources Minister Scott Stewart at this morning’s North West MPX conference in Mount Isa, which runs until Thursday.

Main image: The Incitec Pivot-owned Mount Isa acid plant

Sulphuric acid was central to the benefaction process for many minerals, including gold, phosphate and rare earths, the Association of Mining and Exploration Companies (AMEC) said.

Related: Vanadium juniors pressed for acid options

Members including vanadium juniors had been sweating on the report, AMEC Queensland director Sarah Gooley (who is at MPX) said.

“We’ve been hearing a lot about this acid report now for months,” Ms Gooley said. “I guess it’s concerning that the timeframes that have been shared with proponents and interested groups like ours continue to be extended.

“The data is critical to the proponents being able to take their projects forward with any certainty, and at the moment, delaying the report means that they don’t have the certainty they need. 

“And of course, funding institutions, banks, everyone likes to have some sort of idea about such a crucial part of the development process especially, I suppose, the vanadium companies.” 

Queensland Acid Study

The Queensland Acid Study was launched at the World Mining Congress in June last year to investigate supply options including importing sulphuric acid, continuing to make acid locally and producing elemental sulphur for benefaction on-site.

It was due to be tabled ‘early’ this year.

Queensland’s largest production comes out of the Incitec Pivot (IPL)-owned Mount Isa acid plant which takes feedstock from the Mount Isa Mines (MIM) copper smelter.

The acid plant has the capacity to produce 3700 tonnes/day. 

MIM’s smelter is scheduled for closure in 2030 as part of a rationalisation of copper operations.

The IPL-owned Phosphate Hill operation south of Mount Isa has long been the beneficiary of production from the Mount Isa acid plant.

IPL also has a claim to most of the 300,000 tonnes of sulphuric acid that are trucked west from the Sun Metals Townsville plant each year. 

Acid is also used to help extract low-grade minerals in heap leach processes. Around 125,000 tonnes is used on the Austral Resources copper operation near Mount Isa alone.

There’s also unmet demand in the form of the emerging vanadium industry located north of Julia Creek and Richmond on the Toolebuc formation. 

Broken Hill-based company Cobalt Blue has developed a process to extract minerals, including sulphur, from pyrites. 

Tailings dams in the North West could prove to be part of the solution with a reclamation process which would yield elemental sulphur.

Related: No report on acid supply shortfall

This includes a process of ‘prilling’ sulphur into small inert balls.

The Queensland Acid Study is part of the Queensland Critical Minerals Strategy. The lead agency is the Department of State Development.