Energy Resources of Australia (ERA) reported on June 5 that it had begun a progressive restart of processing operations at its Ranger uranium mine in Australia’s Northern Territory. The processing plant had been shut down since December 7, 2013, following a leach tank failure that allowed the escape of slurry containing a mixture of mud, water, ore and acid. The slurry mixture was fully contained within the processing area and had no impact on Kakadu National Park, which surrounds the mine site.

The restart of Ranger processing operations followed approvals from the Northern Territory Department of Mines and Energy and the commonwealth minister for industry.

On March 27, ERA reported the findings of an independent investigation that it commissioned into the leach tank failure. The first phase of the investigation found that the rubber lining inside the plant’s Leach Tank 1, which protects the tank structure from corrosion, had been damaged as a result of wear from a partially failed baffle inside the tank.

The damaged rubber lining allowed the acidic slurry mixture to come into contact with the tank’s steel wall, which subsequently corroded and ultimately led to the failure of the tank.

ERA decided to redesign and replace the baffle supports in all of the leach tanks before returning them to service.

The investigation commissioned by ERA was separate from and run in parallel with a joint investigation undertaken by a government-appointed taskforce charged with overseeing the regulatory response to the leach tank incident.

With the progressive restart of Ranger processing operations to occur throughout the second and third quarters of 2014, ERA’s 2014 production of uranium oxide is expected to be between 1,100 and 1,500 mt. The company produced 2,960 mt of uranium oxide in 2013.