In the last fifty years uranium has become one of the world's most important energy minerals. It is used almost entirely for making electricity, though a small proportion is used for the important task of producing medical isotopes.
Uranium averages about 2.8 parts per million of the earth's crust. Traces of it occur almost everywhere. It is more abundant than gold, silver or mercury, about the same as tin and slightly less abundant than cobalt, lead or molybdenum. Vast amounts of uranium also occur in the world's oceans, but in much lower concentrations.
Most of the uranium ore deposits at present being mined have average grades in excess of 0.10% of uranium - that is, greater than 1000 parts per million. Some uranium is also recovered as a co-product with copper, as at Olympic Dam in Australia, or as a by-product from the treatment of other ores, such as the gold-bearing ores of South Africa. In these cases the concentration of uranium may be as low as a tenth of those in orebodies mined primarily for their uranium content.
The first major producer of uranium in Australia was the Government-owned Rum Jungle project in the Northern Territory which operated from 1954 to 1971. It was closely followed by Radium Hill in South Australia, then Mary Kathleen in Queensland.
As a result of intensive exploration in the late 1960s Australia began to emerge as a potential major source of uranium for the world's nuclear electricity production. At the beginning of the 1970s a series of important discoveries was made, particularly in the Northern Territory. Names like Ranger, Jabiluka and Nabarlek, all in the Northern Territory; Yeelirrie in Western Australia; Olympic Dam (Roxby Downs) in South Australia became familiar.
Today Australia's share of the world's uranium resources in the low cost category is about 30%. Other countries with major uranium deposits are Canada, Kazakhstan, South Africa, Namibia, Brazil and the USA.
|tonnes U||percentage of world|
The Nabarlek mine was the first of the uranium deposits discovered in the late 1960s to early 1970s to come into production. The main orebody, which contained about 11,000 tonnes U3O8, was mined and stockpiled when operations commenced in 1979. The stockpiled ore was processed from 1980 to 1988.
The next mine was Ranger, owned by Energy Resources of Australia Ltd (ERA) and located about 230 kilometres east of Darwin. Mining commenced in 1980 and is continuing. Ranger then consisted of two orebodies with a total of approximately 110,000 tonnes of U3O8, but one of these, with half of that ore, is now mined out. Capacity is about 5000 tonnes U3O8 per year.
In 1991 ERA purchased the Jabiluka uranium orebody, some twenty kilometres to the north. This is one of the world's larger known uranium deposits, with reserves containing 71,000 tonnes of U3O8. The Jabiluka lease abuts the Ranger mining lease so subject to relevant approvals, the ore from Jabiluka could be processed to U3O8 at the Ranger mill.
Olympic Dam, 265 km north of Port Augusta in South Australia, commenced operations in 1988 and became part of BHP-Billiton in 2005. It is potentially the world's largest uranium producer, with ore reserves containing 390,000 tonnes U3O8, 12 million tonnes of copper and significant amounts of gold and silver. Total uranium resources are 1.5 million tonnes U3O8. Capacity was increased to 4700 tonnes U3O8 per year in 1999 and there are plans for a further increase to 15,000 t/yr.
Beverley, the country's first mine to utilise in situ leaching, commenced operation in South Australia late in 2000. It is a small (1000 t/yr) in situ leach (ISL) mine. Most US uranium production is by this method.
Kintyre, in WA, is another prospective mine. It would be a small operation, producing 1800-2000 tonnes of U3O8 per year and disturbing only about 250 hectares.
Australia exports about 10,000 tonnes of U3O8 per year and the value of this has risen to some $500 million per year.
Summary of resources in operating and some prospective Australian uranium mines
|Deposit||Grade U3O8||Contained U3O8||Category|
|Olympic Dam, SA||0.05%||392,000 t||Proved & Probable Reserves|
|Ranger, NT||0.24%||43,900 t||Proved & Probable Reserves|
|Jabiluka, NT||0.51%||71,000 t||Proved & Probable Reserves|
|Koongarra||0.8%||14,540 t||Proved & Probable Reserves|
|Kintyre||0.2-0.4%||35,000 t||Reserves & resources|
|Yeelirrie||0.15%||52,000 t||Indicated Resources|
At conventional mines, the ore goes through a mill where it is first crushed. Primary crushing breaks up the largest pieces followed by fine crushing to reduce the material to small pieces of about 20 mm and less. The 'fine' ore is then ground in water to produce a slurry of fine ore particles suspended in the water. The slurry is leached with sulfuric acid to dissolve the uranium oxides.
Most of the ore however remains undissolved in the leaching process, and these solids or 'tailings' are then separated from the uranium-rich solution, usually by allowing them to settle out. The liquid containing the uranium is filtered and the uranium then separated by solvent extraction.
Finally the uranium is recovered in a chemical precipitate which is filtered and dried to produce a uranium oxide concentrate, about 99% U3O8 (a mixture of UO2 and UO3). It is then packed into 200 litre steel drums which are sealed for shipment. The U3O8 is only mildly radioactive. (The radiation level one metre from a drum of freshly-processed U3O8 is about half that - from cosmic rays - on a commercial jet flight. )
At Beverley and Honeymoon, the mining method is in situ leaching (ISL). This means that the mining is accomplished without any major ground disturbance. Weak acid with a lot of oxygen injected into it is circulated through an enclosed underground aquifer which holds the uranium ore in loose sands. The leaching solution with dissolved uranium is pumped to the surface treatment plant. Uranium is separated by ion exchange and is then recovered as a chemical precipitate as described above.
Wastes from Mining and Milling
Solid waste products from the conventional milling operation are pumped as a slurry to a tailings dam. These wastes comprise most of the original ore and they contain most of the radioactivity in it. In particular they contain radium, present in the original ore.
When radium undergoes natural radioactive decay one of the products is radon gas. Because radon and its decay products (daughters) are radioactive and because the tailings are now on the surface, measures are taken to minimise the emission of radon gas. During the operational life of a mine the material in the tailings dam is usually covered by water to reduce surface radioactivity and radon emission emission (though neither pose a hazard at these levels).
On completion of the mining operation it is normal for the tailings dam to be covered with some two metres of clay and topsoil to reduce radiation levels to near those normally experienced in the region of the orebody, and for a vegetation cover to be established. At Ranger and Jabiluka, tailings will be returned underground, as was done at the now-rehabilitated Nabarlek mine.
Run-off from the mine stockpiles and waste liquors from the milling operation are collected in secure retention ponds for isolation and recovery of any heavy metals or other contaminants. The liquid portion is disposed of either by natural evaporation or recirculation to the milling operation. Most mines adopt a "zero discharge" policy for any pollutants.
With ISL no tailings are involved and very little waste is generated. The quality of the groundwater returns to normal once the oxygen input is discontinued. ISL thus has clear environmental advantages in the places it can be applied.
All mining methods, tailings and run-off management and land rehabilitation are subject to Government aproval, regulation and inspection.
The Health of the Miners
In Australia all uranium mining and milling operations are undertaken under the Code of Practice and Safety Guide for Radiation Protection and Radioactive Waste Management in Mining and Mineral processing. This was drawn up by the Commonwealth in line with recommendations of the International Commission on Radiological Protection (ICRP), but it is administered by state health and mines departments. The Code, which was updated in 1995 and again in 2005, sets strict health standards for radiation and radon gas exposure, for both workers and members of the public.
Uranium itself is only slightly radioactive. However radon, a radioactive gas, is released to the atmosphere in very small quantities when the ore is mined and crushed. Radon, one of the decay products of uranium and radium, occurs naturally in most rocks and minute traces of it are present in the air which we all breathe. Other radioactive decay products are also present in the ore.
At the relatively high concentrations associated with uranium (and some mineral sands) mining however, radioactivity is a potential health hazard. Consequently special precautions are taken during the mining and milling of uranium ores to protect the health of the workers. These precautions include:
If uranium oxide is ingested it has a chemical toxicity similar to that of lead oxide. Similar precautions to those in a lead smelter are therefore taken when handling it.
In 1953 the Australian parliament passed the Atomic Energy Act which set in train research on nuclear energy and plans to construct a nuclear power reactor south of Sydney. However, this project was abandoned in 1972 and the focus reverted to developing enrichment technology which might add value to the country's uranium.
In 1975 the Australian Government set up the Ranger Uranium Environmental Inquiry - often referred to as the 'Fox Inquiry', to investigate and advise on both uranium policy in general and on uranium mining in the Alligator Rivers area in particular. It lasted almost two years, heard 303 witnesses and produced two reports which identified concerns about some aspects of the use of nuclear energy and urged caution at all stages.
Following publication and consideration of the Inquiry's Reports, the Federal Liberal Government announced in August 1977 that it would approve the development and export of Australia's uranium. The approval was subject both to stringent environmental requirements and safeguards to prevent the diversion of uranium from peaceful uses. These export arrangements, involving the application both international and bilateral safeguards (see below) have remained virtually unchanged since, through successive governments.
However, in other respects federal government uranium policy has varied.
In 1983 the new Labor government approved the Nabarlek and Ranger mines which were then already operating, and also development of the Olympic Dam mine - the so called "three mines" policy. Proposals for Jabiluka, Koongarra and Yeelirrie were shelved, although in most cases mining, environmental and Aboriginal approvals had been obtained. There were even sales commitments for several years' production from Jabiluka.
In 1984 the Australian Science and Technology Council (ASTEC) Report, on Australia's role in the nuclear fuel cycle, commissioned by the Labor government, recommended not only proceeding with uranium mining but also becoming involved with other stages of the nuclear fuel cycle such as enrichment. It also stressed the need for international collaboration in management and disposal of high-level nuclear wastes.
The "three mines" policy was later seen to be illogical and in 1988 the Labor Party established a committee to review it. This recommended that the Commonwealth Government should relax the policy so that other orebodies could be developed.
The report also recommended that uranium enrichment should be allowed in Australia. Despite these recommendations (and similar ones from the Industry Commission), in 1991 the ALP left its uranium policy unchanged.
In 1996 a Liberal-National Party coalition government came to power and uranium mining was then treated the same as any other mining, except that export controls remained as before, to effect non-proliferation objectives. Expansion plans for Ranger and Olympic Dam were pending. Also in the light of stronger world uranium markets, proposals for Jabiluka, Kintyre and other mines were able to be brought forward and other prospects re-examined. In 2000, the first new mine, Beverley, opened.
Safeguards to Prevent Military Use
Among uranium exporting countries Australia has some of the strictest conditions relating to the use of its uranium. These safeguards (inspections and accounting procedures) ensure that uranium exported from Australia is used for peaceful purposes only and is not diverted for military purposes or used in a way which adds to the proliferation of nuclear weapons.
Agreements to this effect between the Australian Government and each country wishing to import Australian uranium are therefore necessary before sales contracts can be completed. Such agreements are in addition to the application of International Atomic Energy Agency (IAEA) safeguards arrangements administered under the Nuclear Non-Proliferation Treaty.
Australia has in force 18 bilateral nuclear safeguards agreements covering 36 countries, including - Argentina, Canada, Czech Republic, Egypt, Finland, France, Hungary, Japan, Republic of Korea, Mexico, Philippines, Russia, Sweden, Switzerland, UK, USA and EURATOM (including all 25 EU countries); and Taiwan.
The safeguards required under these bilateral agreements with Australia are additional to those under the Non-Proliferation Treaty. Among other things they permit the reprocessing of used fuel only as part of a recipient country's nuclear energy program that has already been approved by Australia. Any reprocessing must be done under IAEA safeguards. The further transfer of nuclear material is only permitted to countries which have bilateral safeguards agreements with Australia.
Government Regulation of Mining
Since the announcement of the Australian Government's Uranium Policy in 1977, legislation has been passed covering a wide range of matters affecting uranium mining, including health, environment and Aboriginal land rights.
The Environment Protection (Nuclear Codes) Act amended in 1978 provides for the protection of the health and safety of the people and the environment from possible harmful effects associated with nuclear activities. Codes of practice have therefore been developed by a joint Commonwealth-State Consultative Committee to cover
Australia is now one of the world's major producers and exporters of uranium. In addition to providing further diversification and strength to the domestic economy it gives Australia a voice in the framing of international nuclear policies and safeguards. It also reduces the need for buyers to seek uranium from countries with less effective safeguards.
URANIUM INFORMATION CENTRE Ltd.
A.B.N. 30 005 503 828
GPO Box 1649N, Melbourne 3001,
phone (03) 9629 7744
fax (03) 9629 7207
Copyright © URANIUM INFORMATION CENTRE Ltd. 2000
Revised: August 2005