11 Dec 2013 16:50pm
WINDHOEK, 11 DEC (NAMPA) Investigations continue into the leach tank failure at the Rössing Uranium mine in the Erongo Region last week, the mines Managing Director Werner Duvenhage said on Wednesday.
All milling operations at the mine came to a standstill last week Tuesday after a disastrous structural failure at one of 12 leach tanks in the processing plant. The incident sparked widespread fears of a possible radioactive leak at the mine.
Leaching is a step in the production of uranium oxide, where the milled ore is leached in a sulphuric acid solution.
The leachate is a mixture of crushed ore, water, acid, manganese and iron. Its uranium content is as in the mined ore about 300 parts per million (ppm), but diluted with the liquids, so radioactivity is significantly less than that of mined ore.
The area where the tank failed has since been demarcated and made safe to prevent unauthorised entry, Duvenhage explained in a media statement made available to Nampa.
Following the incident, regular measurements by the Radiation Safety Section of the mine have shown radiation dose levels have not increased, and have remained well within safe levels.
Duvenhage thus assured workers and members of the public that monitoring will continue to ensure exposures to the clean-up team will not exceed the normal occupational exposures in the area.
Rössing remains at all times committed to the health and safety of the employees and the community, and the protection of the environment, he added.
The mines milling operation was stopped after the spill, but is expected to restart after restoration work has been undertaken.
A restoration schedule is currently being developed.
About the financial implications of the restoration work as well as impacts to the mines production, Duvenhage said the results are yet to be determined.
Rössing is working with the relevant regulatory authorities in Namibia in the management of the incident, he continued.
Meanwhile, a similar spill happened at the Rio Tinto Energy Resources Australia (ERA) Ranger mine in the Northern Territory, just days after the incident in the Erongo Region.
The Australian government suspended processing operations after a leach tank with a 1.5 million-litre capacity burst and spilled out a radioactive and acidic slurry last Saturday, international reports stated.
That spill raised extreme concerns from environmentalists, who pointed out that the two facilities are of similar age and construction.
Rio Tinto Group is a British-Australian multinational metals and mining corporation with headquarters in London, in the United Kingdom, and a management office in Melbourne, Australia.
It has a 69 per cent ownership stake in Rossing Uranium.
The company was founded in 1873, when a multinational consortium of investors purchased a mine complex on the Rio Tinto river, in Huelva, Spain, from the Spanish government.