Heritage Minerals will look into roasting pyrite at its Mount Morgan gold-copper project in what could prove a key solution to Queensland’s forecast sulphuric acid shortfall.

The company is progressing toward financial close for its Stage 1 project within the next several weeks, and will then commence full construction of its tailings processing and rehabilitation project, according to Heritage Minerals corporate affairs director Craig Wilson.

“With plant construction underway, Heritage Minerals will turn its attention to a feasibility study to roast pyrite for production of sulphuric acid – the Stage 2 project,” he said.

The Stage 2 project would involve more capital and higher revenues, Mr Wilson said.

“We are looking at the project as much as a regional economic development project as anything else – the new capital plant will help activate economic activity and zones between Mount Morgan, Stanwell and Gracemere.

“The production of acid is the critical input for the critical minerals industry – no acid, no critical minerals processing.

“By removing pyrite from the Mount Morgan site, which is acid-forming rock, this reduces acid on the site which flows into Great Barrier Reef in high rainfall events.

“Heritage Minerals believes it will be able to do this efficiently as Heritage Minerals technology will also allow economic reprocessing of subsequent waste for gold, copper and cobalt.

“We have many years of data regarding volume and type of pyrite rock on site. 

“We have recently shipped more samples to a specialist lab in Germany for analysis to underpin designing of a roasting facility.”

Related: Heritage lines up Mount Morgan processing gear

The Queensland Government recently released the findings of a study commissioned into supply and demand for sulphuric acid in the North West and North East Minerals provinces of Queensland.

With the potential underutilisation and retirement of Glencore’s Mount Isa copper smelter beyond 2030, there was a high degree of uncertainty about the future availability of nearly 50 per cent of the Queensland acid supply chain, the report stated.

At the same time, demand for sulphuric acid in northern Queensland’s minerals sector is expected to soar from current levels of about 1.23Mtpa to reach 2.86Mtpa to 5.23Mtpa by 2035.

Related: AMEC urges swift action on critical supplies

Heritage Minerals is not providing a figure for potential production rates at Mount Morgan, but Mr Wilson said it would be enough to plug forecast gaps identified in recent analysis.

The life of the Stage 1 project at Mount Morgan was expected to be about eight years, while the Stage 2 proposal (which could start during Stage 1) would run for more than 20 years, he said.

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