Diversion risk identified for McArthur River

An assessment by operator Glencore shows there is a “medium to long term” risk the river will “rapidly” alter course

Aerial shot of McArthur River mine

THE McArthur River is at risk of redirecting itself through the mine site, according to an assessment by operator Glencore.

The danger was outlined in a report by the independent environmental monitor, released yesterday.

The report says there is a “medium to long term” risk the river will “rapidly” alter course to either form a new channel or revert back to its original path. The river was diverted in 2007 to allow for an expansion of Glencore’s zinc mine.

Independent monitor David Browne, from consultancy group Erias, said the process of the river realigning could begin within five to 10 years if it wasn’t addressed.

“If it were to occur, it could potentially result in large quantities of sediment being washed down the McArthur River and impacting the mine levee wall,” he said. “Tonnes and tonnes of soil would be washed down and you would create then an unstable river channel which would continue to erode.”

Mr Browne said Glencore needed to further investigate the issue to find solutions.

The report delivered yesterday was Erias’ fifth and final monitoring report.

Mr Browne said there had been “significant improvements” in the environmental health of the mine site since the monitoring program began. At the time, plumes of smoke could be seen coming from the waste rock dump, the result of pyrite coming into contact with air and water.

Mr Browne said a lot of work had gone into fixing this.

He nominated the management of water on the tailing facilities and elsewhere on site as some of the big improvements.

But there were also frustrations — including in five years Glencore had still not finished putting doors on its concentrate shed at the Bing Bong loading facility, which could create potential problems with concentrate dust.

MRM general manager Sam Strohmayr said the mine took the findings seriously and would continue to work to improve the health of the river and surrounding environment.