The Ranger uranium mine has been the site of another pollution incident, with a ruptured tank releasing acidic radioactive slurry.
At 1am on Saturday morning a hole was discovered in the side of a leach tank within the processing area, with staff evacuated before it collapsed.
The capacity of the tank was approximately 1,450 cubic metres.
While no explosion occurred, it is not yet clear how much material leaked out of the faulty tank.
A crane that had been used to assist in blocking the original hole was damaged when the tank gave way.
Traditional owners of the north-east of Kakadu National Park where the mine is located say the Mirrar people are deeply concerned, with the latest breach the third in just over four weeks.
The mine is looking to develop underground operations, but has said it will not do so without the support of the Mirrar people, support which many say is now off the table, AAP reported.
"Day by day, litre by litre, incident by incident, they're losing whatever trust traditional owners have in them," Mirrar spokesperson Justin O'Brien said.
"This is up to a million litres of radiological material in the form of an acid exploding from a drum, bending a crane, twisting metal all around it, pouring down into stormwater drains, with 20 or so people ordered to evacuate.”
Mine operator Energy Resources of Australia (ERA) says the containment processes in place at the site prevented impact to the surrounding environment.
“ERA is confident that Kakadu National Park will not be impacted as a result of this incident,” the company said in a statement.
“Ranger mine has multiple levels of protection in place to contain and manage spills, including bunding, protective barriers and channelling. These containment systems have operated as designed during this incident.”
ERA general manager operations Tim Eckersley said the clean-up on site is continuing.
However O’Brien said the incident proved the mine was not being regulated properly and will write to the World Heritage Committee requesting international help.
He is also calling for an external investigation.
Environmental groups are also calling for the mine to halt its operations until an independent review is completed.
Australian Conservation Foundation spokesman Dave Sweeney has previously called on Rio Tinto to ''reconsider the project'' and says the mine’s days are numbered.
"The time for mining a problematic and polluting mineral in a World Heritage area is over," he said.
In early November a mine left the site’s controlled areas sparking fears of contamination, while later that month four uranium storage barrels were discovered in bushland near Darwin.
O’Brien has previously called on the Federal government to step in to ensure potentially harmful incidents stop occurring as a result of the uranium operation.