SYDNEY, March 27 (Reuters) - Damaged rubber lining on a tank led to a massive uranium leak from a processing plant in Australia late last year, a subsidiary of global mining giant Rio Tinto said on Thursday.
An investigation into the spill found that more than 1 million litres of liquefied uranium material escaped from a three storey-high steel tank when its wall corroded after the rubber lining was damaged, according to Energy Resources of Australia Ltd. The firm is 68.4 percent owned by Rio Tinto.
Workers were evacuated from the Ranger mine site in the early hours of Dec. 7 when a hole was discovered in the tank. The tank subsequently split, knocking over a crane and spilling the uranium onto the ground.
Operations were suspended after the spill.
The damaged tank has been dismantled and removed, while inspections of six other tanks at the site discovered signs of steel corrosion in one of them, ERA said.
The investigation recommended 35 steps relating to inspections and testing of the leach tanks be taken before operations are allowed to resume.
Australian Conservation Foundation national nuclear campaigner Dave Sweeney said the findings showed inadequate safeguards existed at the site.
“This spill was a combination of metal and management fatigue,” he said. “It clearly demonstrates the dangers that exist at Ranger.”
ERA Chief Executive Andrea Sutton said there had been no environmental damage in areas close to the spill due to a containment system , adding the surrounding Kakadu Park, a World heritage-listed preserve, was also unaffected.
“The detailed review is an important part of helping restore community and stakeholder confidence in the Ranger plant operations,” Sutton said.
The investigation, commissioned by ERA, was separate from ones by government task forces, which must sign off before operations can restart.
ERA said it had built up sufficient stockpiles of processed uranium, known as uranium oxide, prior to the spill to meet its sales commitments through the first half of this year and was looking at ways to meet its second-half commitments.
Uranium oxide is mainly bought for use in nuclear power generating plants.
Production stopped for five months in 2012 at the Ranger mine, which can supply as much as 10 percent of the world’s uranium, due to heavy rains, forcing ERA to purchase more than 2,000 tonnes of uranium to cover deliveries.
Editing by Joseph Radford