A week before a uranium mine in Kakadu National Park spilled a million litres of radioactive slurry a Rio Tinto-owned African mine had a similar accident.
Rio Tinto owns Energy Resources of Australia (ERA), the company which operates the Ranger mine in the Northern Territory, where a crack in a leach tank turned into a massive spill in the early hours of Saturday.
ERA said it had completed its preliminary inspections and was satisfied the surrounding area was safe and Kakadu had not been contaminated, but there were still concerns in the scientific and Indigenous communities that rain had the potential to carry the contaminated slurry.
On 3 December, a similar accident happened at Rossing, a mine in Namibia owned by Rio Tinto, with the company reporting a leach tank failed but it did not say how much of the radioactive slurry – which, like the Ranger spill, also contained acid – was spilled.
It said some employees were treated at the scene for “minor” injuries and there was no environmental impact. The leach tank had structural damage and Rio Tinto was investigating the cause of the spill.
Dr Gavin Mudd, an environmental engineer from Monash University, said it was too early to say the national park and creeks surrounding the Ranger mine were completely safe, though at this stage it did appear the spill had been contained within the mining operation.
Mudd said because of rainfall there would “almost definitely” be some contamination outside the mine, but only to a small degree and it would be diluted. “The primary issue is that it breached the containment lines. They should not fail, ever,” Mudd said. “It’s an extremely important failure.”
Mudd said it was concerning Rio Tinto had two mines with similar spills in the same week and that could point to a “lack of maintenance, lack of oversight, continual deterrence of maintenance … maybe construction quality”.
The Gundjeihmi Aboriginal Corporation’s chief executive, Justin O’Brien, said there had been no independent verification of ERA’s claims that the environment and surrounding park had not been affected by the spill on Saturday. An indigenous community of about 60 Mirarr people live about 7km downstream from where the spill happened.
“How can the Mirarr [people] be expected to trust a company that has continuously reassured them and yet continues to have major failures of protocol and infrastructure?” he said. “The Office of the Supervising Scientist is not politically independent. Without a comprehensive, independent audit of the entire ageing Ranger operation the Mirarr will continue to be deeply concerned for the safety of people and country.”
The Ranger uranium mine has had a chequered history when it comes to safety breaches dating back to 1979, when there were two diesel spillages within months of each other.
In 2011 the mine had to close for months after its tailing ponds almost overflowed and it was forced to pump contaminated water into one of its mines to prevent it going into Kakadu National Park.
The year before, a review found the mine had been leaking 100,000 litres per day of contaminated water into fissures beneath Kakadu, although it has not been established where the leaked water went or what its effect on the environment would be.
Rio Tinto and the supervising scientist, Richard McAllister, did not respond to a request for comment.
The mine was suspended from processing uranium on Monday by the federal government as it launched an audit of the site.
ERA has applied to open another uranium mine 22km from the Ranger site but has said it will not go ahead without the permission of the Mirarr people.
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