| Ranger | |
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Ranger mill complex |
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| Location | |
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Ranger Uranium Mine
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| Location | Kakadu National Park |
| Territory | Northern Territory |
| Country | Australia |
| Owner | |
| Company | Energy Resources of Australia Limited |
| Website | http://www.energyres.com.au/ |
| Production | |
| Products | Uranium |
| History | |
| Opened | 1980 |
The Ranger uranium mine is surrounded by Kakadu National Park, in the Northern Territory of Australia, 230 km east of Darwin. The orebody was discovered in 1969, and the mine commenced operation in 1980, reaching full production of uranium oxide in 1981. It is operated by Energy Resources of Australia, a 68% subsidiary of Rio Tinto Group.
Uranium mined at Ranger is sold for use in nuclear power stations in Japan, South Korea, UK, France, Germany, Spain, Sweden and the United States.[1]
The original orebody was completely mined out by the end of 1995, although some ore remains stockpiled. A second orebody ("Ranger 3") began mining in 1997. Both have been open-pit mines.
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The orebody was discovered in 1969, and the mine commenced operation in 1980, reaching full production of uranium oxide in 1981.
Owing to the environmental sensitivity of the site, a special statutory authority, the Supervising Scientist, was created to provide oversight of the operation and conduct environmental research in the region.
The Ranger Uranium Mine covers two of a line of uranium orebodies that extend from near Nourlangie Rock in Kakadu north-eastwards to Koongarra, underneath Mount Brockman, then northwards through the Ranger One line of orebodies (in order Number 2, Number 1, and Number 3), then via Hades Flat, where there is uranium mineralisation, to Jabiluka where the line turns westward through the Barote and Ranger 4 orebodies. The mine covers No 1 Orebody and No 3 Orebody. No 2 orebody was excluded from the mining lease at the request of the traditional owners and included in Kakadu National Park. From Ranger 4 the line again turns northwards and then swings westward round an Archaean basement dome before turning south towards Nourlangie Rock again. Uranium mineralisation is known at several other places along this line but has never been explored in detail because of the creation of Kakadu. The name 'Ranger' for the series of discoveries made by Geopeko Limited, the exploration arm of the Australian mining company Peko-Wallsend Limited, in the period 1969 to 1972, was thought up by Judy Ryan, the wife of the geologist in charge of the program. Koongarra and Jabiluka were retained by the companies that found them: Noranda Australia and Pancontinental Mining respectively, although since sold to other parties. The other discoveries are enclosed in the National Park, locking up an energy source that is estimated to be greater than the oil reserves of Saudi Arabia. (12)
Ore is ground, then leached with sulfuric acid. Uranium is removed using kerosene with amine then stripped with ammonium sulfate solution and gaseous ammonia. Ammonium diuranate is precipitated by increased pH and converted to uranium oxide (U3O8) in a furnace.[1]
In early 2006, ERA announced an expansion to the ore processing plant which will allow production to extend into lower-grade material and in November 2006 the company announced plans to invest in a laterite processing plant, which will allow it to process ore with a high clay content that has been stockpiled since the mine began operating. This ore had been already included in stated reserves. The laterite processing plant will contribute 400 tonnes of uranium oxide per year from 2008 until 2014.[2]
The main long-term environmental impact of uranium mining is that posed by the large volumes of tailings, mining waste in the form of particularised sand, which remain on the minesite. Guidelines from the International Atomic Energy Agency describe the project area as particularly unsuitable for tailings storage.[3] The original pit is now being used to store tailings.
Due to inadequate estimation of annual rainfall in the design phase, [4] the mine has continued to suffer routine seasonal failure of the water management systems. [5]
A mine closure model has been developed by the company and is provided for in the balance sheet to the value of over A$180 million.[6] However opponents warn that this may be as little as one fifth of the final cost of rehabilitation. [7] The rehabilitation plan has not been made public, and environmentalists warn that plans for further expansion [8] will further widen the gap between needs and means for remediation of the mine site.
Environment Australia (an agency of the Government of Australia) have documented over 200 environmental incidents since 1979.[5]
In May 2005, the company was convicted for breaching environmental guidelines - the first such prosecution of a mining company in the Northern Territory, relating to accidental radiological exposure to ERA employees.[9] Radiologically contaminated process water had contaminated the drinking water supply and some workers drank and washed in the contaminated water. The maximum radiation exposure of workers was likely to have been much less than the regulatory limit, and no harmful long-term health effects are likely.[10]
Other incidents involving decontamination of vehicles have been identified.[10] When the work-for-welfare mechanic in Jabiru opened the engine bay, he was unaware of the nature of the mud and dirt which fell on the floor. The court heard that in the following weeks, after he had swept the material outside his shed, his children played and built sandcastles in mud contaminated with uranium.[11]
Another significant controversy over Ranger's environmental impact is the public legal confrontation over releases into Magela Creek in the 1995 wet season. More recently, the ARRAC report from 2002 details a major leak of about 2 megalitres of potentially polluted water, over a number of months. In 2007, water breached a retention pond, overflowing back into the pit. The original authorisation required that this water be contained at all times. In 2006, water management systems were knocked into disarray by Cyclone Monica.
In May 2010, it was reported that a tailings dam may have released millions of litres of radioactive water into world heritage-listed wetlands in Kakadu National Park, home to about 500 Aboriginal people.[12]