Rio Tinto Alcan pleaded guilty in court on Wednesday, admitting it did not have the capacity to deal with flooding which hit its red mud dam at Yarwun in Queensland last year.
The miner will be fined between $30,000 and $50,000 for breaching its environmental obligations at its alumina plant west of Gladstone.
Under the requirements Rio must ensure it has sufficient residue management area storage at its operations, a figure which is calculated on expected rainfall from a one in 50-year three month long wet season, The Gladstone Observer reports.
An investigation conducted by the Department of Environment and Heritage Protection found progress on an upgrade to storage capacities was too slow.
Rio has since met the capacity requirements and is on schedule to meet this year’s conditions.
The Gladstone Magistrate’s Court adjourned a final verdict on the case until Thursday afternoon.