A multi-disciplinary team from the Water Research Centre and more broadly the UNSW GWI has prepared a report on the failings of the environmental regulatory process for the McArthur River Mine which was released this week. The report found up to 22 sacred Indigenous sites and an important river system in the Northern Territory face irreversible cultural and ecological damage if the McArthur River Mine operations continue unabated. Together with the Environmental Centre of the Northern Territory (ECNT), we looked at the publicly available information on water-related issues related to McArthur River Mine’s operations and expansion over the period 2007-2018. We concluded that short-term problems such as the spontaneous combustion of waste rock that has plagued the site since 2014 paled in comparison to the long-term risks of metallic and acid contamination of the groundwater system and the McArthur River. Worse, even after such risks were identified by the Independent Monitor, the report identified repeated failures of the mine site operator, Glencore Australia, and the NT mining regulator to act quickly to mitigate the identified risks.

Some of these problems identified in the report include: acid build-up in waste rock that was misclassified as harmless; seepage from a tailings dam into groundwater and nearby creeks; and risks to sacred sites. As early as 2008, the Independent Monitor suggested that the waste rock had been misclassified as benign. It was only when the waste rock began smoking with sulphur dioxide plumes in 2014 that the mine was asked to submit an environmental impact statement, and it took a further six years for the Mining Regulator to approve the mining operator’s proposal to fix the problem in December 2020.

WRC’s Associate Professor Fiona Johnson, one of the report’s contributors, says a misclassification of waste rock as benign is no small matter. “Rock that can cause acid to form needs to be stored differently than benign rock,” she says. “Because this waste rock was misclassified, it meant that acid could have caused harm to the surrounding environment even though the Independent Monitor raised concerns very early on. It took far too long for the Independent Monitor’s concerns to be addressed by the mine, and the longer this rock was exposed to air and water, the more acid – in this case sulphuric acid – and metals could have entered the surrounding environment.”

We also found that the mine operator has assumed that the seepage from the tailing storage facility has a neutral pH. But if water becomes more acidic, it will be able to carry toxic metals into the groundwater and river systems and poses risks to the river ecology and Indigenous communities downstream who depend on it. A/Prof. Johnson says although the mine operator has attempted to stop the leakage through installation of barriers and seepage recovery bores, seepage from the tailings dam continues to be an issue.

There are 11 registered sacred sites within or near the mine, meaning they have been documented and evaluated by the Aboriginal Areas Protection Authority (AAPA). However only the impacts to a single water-related site, Djirrinmini waterhole, have been considered during the environmental impact statement (EIS) process. A/Prof. Johnson and her fellow authors think this is unacceptable. “The mine has not carried out enough baseline monitoring of the Djirrrinmini waterhole – which is believed to be a breeding site for freshwater sawfish – through the wet and the dry seasons.”

We found that there are extended delays between the Independent Monitor reporting of issues and the mine taking actions to address them, as exacerbating the problems. We concluded that in addition to expediting the monitoring process, much more should be done to ensure ongoing and meaningful engagement with communities in Borroloola and surrounding districts in future reporting from the Independent Monitor.

The report is available here