AN INDEPENDENT monitor’s report into Xstrata’s McArthur River mine has said there were extreme risks of a tailings dam bank breaking as well as acid draining into one of the river’s tributaries. Environment Centre NT director Dr Stuart Blanch said the independent monitor project director Philip Mulvey told a December stakeholder meeting there was an “extreme risk” of bank failure of the tailings dam. The October released monitor’s audit report for 2010 stated the tailings capacity needed to be increased by the start of the 2010-11 Wet. It also said there was an extreme risk of acid caused by leaching, draining into Surprise Creek.