www.world-nuclear-news.org /Articles/Ranger-spillage-clean-up-completeRanger spillage clean-up complete - World Nuclear News
3-4 minutes27 March 2014
The clean-up of spilled slurry material at the Ranger uranium mine has been completed, Energy Resources of Australia (ERA) reported. A damaged rubber liner has been identified as the cause of last year's leaching tank rupture.
The failed tank, number 1, has now been dismantled at Ranger (Image: ERA) One of several leaching tanks at Ranger ruptured on 7 December releasing a mixture of slurry containing mud, water, ore and acid. The plant's containment systems - including barriers and channelling - kept all the slurry mixture within the mine's processing area. Processing operations at the mine have remained offline since the incident.
ERA - majority owned by Rio Tinto - has announced that it has completed dismantling and removal of the failed tank and its associated infrastructure from Ranger's processing area. The sections of the tank will be stored on site for inspection. The clean-up of slurry material in the area around the failed tank has also been completed.
While an investigation into the incident by a government-appointed taskforce continues, ERA has concluded its own investigation. The company said that the tank's rubber lining had been damaged by a partially failed baffle inside the tank. The baffle is a plate that stirs the slurry mixture. Modifications made to the tank in 2009 were the likely cause of this baffle failure. The damaged lining allowed acidic slurry mixture corrode the tank's steel wall, leading to its failure.
The remaining six leach tanks at Ranger have been emptied and inspected. Metal fatigue was found on the baffle support in one of these and, as a precaution, ERA will redesign and replace the baffle supports in all of them.
ERA's investigation highlighted seven critical actions that must be taken before processing operations are restarted. These relate to inspections and thickness testing of the leach tanks and other processing plant tanks. The company noted that restart remains subject to approval by Australia's industry minister and Northern Territory's department of mines and energy.
ERA said that it built a large inventory of uranium oxide in 2013 and has sufficient to meet sales commitments during the first half of 2014. It is "evaluating a range of alternatives" to meet its commitments in the second half of the year. The company said the full financial and production impact of the tank failure will depend on a range of factors, including when it is authorised to restart processing operations.
A similar tank failure occurred on 3 December at the Rössing mine in Namibia, in which Rio Tinto also holds a majority stake. A preliminary investigation concluded that failure was due to localised external corrosion. Processing operation at Rössing have resumed following the removal of the failed tank and checks on the eleven others.
Neither the Ranger or Rössing incident resulted in any injuries nor was there any environmental impact to the surrounding areas.
www.abc.net.au /news/rural/2022-02-02/ranger-uranium-mine-cleanup-cost-blowout-to-2-2-billion/100798666Ranger uranium mine rehabilitation costs could blow out to $2.2 billion, Energy Resources tells ASX
Daniel Fitzgerald4-5 minutes 2/2/2022The rehabilitation of a decommissioned uranium mine in Kakadu National Park could cost up to $1.2 billion more than expected and take two years longer than initially planned.
Key points:
- Rehabilitation of Ranger uranium mine to cost between $1.6 billion and $2.2 billion
- Timeline of clean-up pushed out by two years
- Gundjeihmi Aboriginal Corporation concerned ERA won't be able to fund extra costs
Energy Resources of Australia (ERA) — a subsidiary of mining giant Rio Tinto — shut down production at its Ranger uranium mine, 250 kilometres east of Darwin, in January last year and has since been working to return the mine site to its original state.
The rehabilitation was originally estimated at $973 million, but in a statement to the ASX on Wednesday, ERA revised costs to be approximately between $1.6 and $2.2 billion.
The company also said clean-up works could continue until the end of 2028, more than two years longer than planned.
The rehabilitation of the Ranger uranium mine will cost much more and take longer than expected.(ABC News: Sara Everingham)
The Gundjeihmi Aboriginal Corporation, which represents Mirarr traditional owners, had been seeking clarity on the expected cost blowouts from ERA.
"We knew it would cost more, but a doubling — to probably the biggest rehabilitation exercise in the history of Australian mining — took us by surprise," chief executive Justin O'Brien said.
"It's not good news, but at least we now have a much greater picture of the true cost."
ERA's statement outlined a number of reasons for the revised cost, including engineering issues, emerging technical risks and additional water treatment costs.
"It is a complex operation and it is in a very sensitive, world-heritage-listed national park, upstream of Aboriginal communities and the Arafura Sea," Mr O'Brien said.
Federal changes needed to extend time frame
ERA's current lease stipulates the company must complete the rehabilitation and be off the mine site by 2026, a condition legislated by the Atomic Energy Act 1953.
With the rehabilitation time frame now stretching into 2028, ERA said it "has been engaging with government and key stakeholders to amend the Atomic Energy Act 1953 and extend the expiry date of ERA's tenure on the Ranger Project Area".
Mr O'Brien said a two-year extension to the rehabilitation was "pretty ambitious".
"If you're going to amend the legislation in Canberra you don't just do it for two years, you give them lots of space to do this," he said.
"If they [ERA] relinquish within another 26 years, then fine."
Chief executive of the Gundjeihmi Aboriginal Corporation, Justin O'Brien speaks about the future of Jabiru.(ABC News: Michael Donnelly)
Can ERA afford the cost blowout?
In light of the cost revision, ERA said it was "currently reviewing all available funding options to ensure that the increased forecast cost of the rehabilitation of the Ranger Project Area will be adequately funded".
As of December 31, 2021 the company had $699 million in cash funding and $535 million held by the Commonwealth government as part of the Ranger Rehabilitation Trust Fund.
ERA's parent company, Rio Tinto said in a statement to the ASX, "it is committed to working with [ERA] to ensure the rehabilitation of the Ranger Project Area is successfully achieved to a standard that will establish an environment similar to the adjacent Kakadu National Park".
Mr O'Brien said that if Rio Tinto and ERA fail to fund the rehabilitation, the Australian government would need to step in.
"At the end of the day, it is important to remember … that the Australian government is ultimately responsible for everything that happened [at Ranger]," he said.
"This is an unprecedented exercise, a mega-project of rehabilitation, in such a sensitive world-heritage listed area. People have to get this right, both the industry and government."
.jpg "Ranger leach tanks 460 (ERA)")
