Information Papers

Uranium Mining

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.

There are many uranium mines operating around the world, in some twenty countries, though more than two thirds of world production comes from just ten mines. Most of the uranium ore deposits at present supporting these mines have average grades in excess of 0.10% of uranium - that is, greater than 1000 parts per million. In the first phase of uranium mining to the 1960s, this would have been seen as a respectable grade, but today some Canadian mines have huge amounts of ore up to 20% U average grade. Other mines however can operate successfully with very low grade ores.

Some uranium is also recovered as a by-product with copper, as at Olympic Dam in Australia, or as 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 that in orebodies mined primarily for their uranium content.

Generally speaking, uranium mining is no different from other kinds of mining unless the ore is very high grade.

Different kinds of mines

Where orebodies lie close to the surface, they are usually accessed by open cut mining, involving a large pit and the removal of much overburden as well as a lot of waste rock. Where orebodies are deeper, underground mining is usually employed, involving construction of access tunnels and shafts but with less waste rock removed and less environmental impact. In either case, grade control is usually by measuring radioactivity as a surrogate for uranium concentration. (The radiometric device detects associated radioactive minerals which are decay products of the uranium, rather than the uranium itself.)

At Ranger in north Australia, Rossing in Namibia and most of Canada's Northern Saskatchewan mines through to McClean Lake, the orebodies have been accessed by open cut mining. Other mines such as Olympic Dam in Australia, McArthur River, Rabbit Lake and Cigar Lake in Northern Saskatchewan, and Akouta in Niger are underground, up to 600 metres deep. At McClean Lake, mining will be completed underground.

Some orebodies lie in groundwater in porous unconsolidated material and may be accessed simply by oxygenating that groundwater and pumping it out - this is in situ leach (ISL) mining. ISL mining means that removal of the uranium minerals is accomplished without any major ground disturbance. Weakly acidified or alkaline groundwater 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 then pumped to the surface treatment plant

About half of the world's uranium now comes from underground mines, about 30% from open cut mines and over 20% from ISL.

Conventional mines have a mill where the ore is crushed, ground and then leached with sulfuric acid to dissolve the uranium oxides. At the mill of a conventional mine, or the treatment plant of an ISL operation, the uranium then separated by ion exchange before being dried and packed.

Known Recoverable Resources of Uranium (tonnes U, % of world)

  tonnes U  % of world 
Australia 1,143,000 24%
Kazakhstan 816,000 17%
Canada 444,000 9%
USA 342,000 7%
South Africa 341,000 7%
Namibia 282,000 6%
Brazil 279,000 6%
Niger 225,000 5%
Russian Fed. 172,000 4%
Uzbekistan 116,000 2%
Ukraine 90,000 2%
Jordan 79,000 2%
India 67,000 1%
China 60,000 1%
Other 287,000 6%
World total 4,743,000  

Reasonably Assured Resources plus Inferred Resources, to US$ 130/kg U, 1/1/05, from OECD NEA & IAEA, Uranium 2005: Resources, Production and Demand.

Australia's Uranium Mines

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 known uranium resources is about one third and it produces about 22% of the world's mined uranium.

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 9300 tonnes of uranium, 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 in the Northern Territory. Mining commenced in 1980 and is continuing on the second of two orebodies, producing about 4500 tonnes of uranium per year - about 12% of world supply from mines.

In 1991 ERA purchased the Jabiluka uranium orebody, some 20 km north of Ranger. This is one of the world's larger known uranium deposits, and its lease abuts the Ranger mining lease so subject to relevant approvals, the ore from Jabiluka could be processed 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 total uranium resources of 1.3 million tonnes uranium. Capacity is about 4000 tU/yr - about 9% of world supply - and there are plans for an increase to 12,700 tU/yr.

Beverley, the country's first mine to utilise in situ leaching, commenced operation in South Australia late in 2000. It is a small (900 t/yr) in situ leach (ISL) mine. Honeymoon is set to start operating in 2008 and will be similar but smaller.

North America's uranium mines

 In Canada, uranium ores first came to public attention in the early 1930s when the Eldorado Gold Mining Company began operations at Port Radium, Northwest Territories, to recover radium. A refinery to produce radium was built the following year at Port Hope, Ontario, some 5000 km away.

Exploration for uranium began in earnest in 1942, in response to a demand for defence purposes. By 1956 thousands of radioactive occurrences had been discovered and three years later 23 mines with 19 treatment plants were in operation. The main production centre was around Elliot Lake in Ontario, but northern Saskatchewan hosted some plants. This first phase of Canadian uranium production peaked in 1959 when more than 12,000 tonnes of uranium was produced. The uranium yielded more in export revenue than for any other mineral export from Canada that year.

Uranium exploration revived during the 1970s with the focus on in northern Saskatchewan's Athabasca Basin. The Rabbit Lake, Cluff Lake and Key Lake mines started up 1975 to 1983. Exploration expenditure in the region peaked at this time, resulting in the discoveries of Midwest, McClean Lake and Cigar Lake. Then in 1988 the newly-formed Cameco Corporation discovered the massive McArthur River deposit. Today Canada's share of known world uranium resources is about 12%, but it produces about one third of the mined uranium.

Canada has almost completed a transition from second-generation uranium mines (started 1975-83) to new high-grade ones, all in northern Saskatchewan.

Cameco operates the McArthur River mine, which started production at the end of 1999. Its ore is milled at Key Lake, which once contributed 15% of world uranium production but is now mined out. Its other former mainstay is Rabbit Lake, which will close in a few years. Areva's Cluff Lake mine has now closed, and is being decommissioned.

McArthur River has enormous high-grade (over 20%) reserves at a depth of c 600 metres. It opened at the end of 1999 and now contributes 17% of world supply. Remote-control raise-boring methods are used for mining and the ore is trucked 80 km south to the modified Key Lake mill, where it is blended with "special waste rock" to produce 7200 tU/yr. Tailings are deposited in a mined-out pit. Cameco is the operator and majority owner, with Areva (30.2%) as partner.

Areva Resources operates the McClean Lake mine which commenced operation in mid 1999 and contributes about 5% of world supply. It has new plant and other infrastructure and uses the first mined-out pit for tailings disposal (the ore having been stockpiled). McClean Lake involves four open pits and later will become an underground mine.

There are also two further new uranium projects coming into production in the next few years in N. Saskatchewan:

Cigar Lake will be a 450 m deep underground mine in poor ground conditions, using ground freezing and high-pressure water jets for excavation of ore. High-grade ore slurry from remote mining will be trucked for treatment at Areva's expanded McClean Lake mill, 70 km northeast, and most of the product then to Cameco's Rabbit Lake mill 70 km east, to produce 7000 tU/yr from 2007. The joint venture is managed by Cameco which holds 50%. Areva holds 37%.

Areva's Midwest mine was to be underground, utilising ground freezing and water jet boring, but may be open pit. The ore will be milled at McClean Lake nearby, to produce 2200 tU/yr.

In the 1950s, the USA had a great deal of uranium mining, promoted by federal subsidies. Peak production was 16,800 tU in 1980, when there were over 250 mines in operation. This number abruptly dropped to 50 in 1984 when 5700 tU was produced, and then there was steady decline to 2003, with most US uranium requirements being imported. By 2003 there were only two small operations producing a total of under 1000 tU/yr.

Cameco operates the Smith Ranch-Highland mine in Wyoming and the Crow Butte mine in Nebraska, both of them small ISL operations. Uranium Resources Inc commenced production from its Vasquez ISL mine in 2004 and from Kingsville Dome in 2006, both in south Texas. Mestena Uranium's Alta Mesa ISL plant in South Texas is also operational.

Conventional (non-ISL) uranium mining in is set to resume after some years. International Uranium Corp (IUC) expects to produce about 1550 tonnes U 3 O 8 (1300 tU) in 2008 through its White Mesa mill in southeastern Utah, from its own and purchased ore, as well as doing some toll milling. IUC is opening its Colorado Plateau /Uravan Mineral Belt mines. It will then begin production from its Henry Mountains mines in Utah including Bullfrog. It will spend $13 million on mill refurbishment, $10 million on mines and then $35 million on the Bullfrog mine for mid 2008 start. It may also reopen its mines in the Arizona Strip in 2007.

Central Asia's uranium mines

 Kazakhstan has been an important source of uranium for more than fifty years. Over 2001-2005 production rose from 2000 to 4357 tonnes U per year, and further mine development is under way with a view to annual production of 15,000 tU/yr by 2010.

Uranium exploration started in 1948 and economic mineralisation was found is several parts of the country and this supported various mines exploiting hard rock deposits. Some 50 uranium deposits are known, in six uranium provinces.

In 1970 tests on in situ leach (ISL) mining commenced and were successful, which led to further exploration being focused on two sedimentary basins with ISL potential.

Up to 2000 twice as much uranium had been mined in hard rock deposits than sedimentary ISL, but almost all production is now from small ISL mines.

In the Caspian province the Prikaspisky Combine operated a major mining and processing complex on the Mangyshalk Peninsula in the 1960s. It was privatised as Kaskor in 1992 and operations ceased in 1994.

The operating and planned ISL mines are in the central south of the country and controlled by the state corporation Kazatomprom.

Stepnoye has been operating since 1978, Tsentralnoye since 1982 - both in the Chu-Sarysu basin, which has more than half the country's known resources.

The No.6 Mining group has operated since 1985 in the Syrdarya basin slightly to the west. All have substantial resources. A new processing plant was commissioned in 2004 at Tsentralnoye

UrAsia Energy Ltd of Canada has bought 70% of the South Inkai project and the Akdala mine, producing 1000 tU/yr from 2006. South Inkai mine will start production in 2007.

Areva holds 51% of the Katco joint venture which operates the Moinkum mine.

The North and South Karmuran mines are operated by Kazatomprom, and will be joined by Irkol and Kharasan in 2007 in the same area. UraAsia has bought a 30% share of the Kharasan project.

Further south in the same Syrdarya basin the Zarechnoye mine is a joint venture with Russia's Tenex, which is buying all the output.

A 2005 KazAtomProm publication listed uranium resources in the Chu-Sarysu and Syrdarya provinces as:

Northern (Stepnoye)
 750,000 tU
Eastern (Tsentralnoye)
 140,000 tU
Western (# 6)
 180,000 tU
Southern (Zarechnoye)
 70,000 tU

this being 72% of total Kazakh U resources and all suitable for acid ISL recovery.

The Navoi uranium mines operate in Uzbekistan.

The Kraznokomensk underground mine in the far east of the Russian Federation is an important source of Russia's uranium and accounts for 7.5% of world supply.

African uranium mines

Uranium production in South Africa has generally been a by-product of gold or copper mining. In 1951 a company was formed to exploit the uranium-rich slurries from gold mining and this grew into Nufcor, which in 1998 became a subsidiary of AngloGold Ltd. In 2007 SXR Uranium One's Dominion mine started production.

In Namibia the large Rossing open cut mine is 69% owned by Rio Tinto and has been in operation since 1976. It has recently had a new lease of life with further development work and produces about 7.5% on world supply.

Also in Namibia, Paladin's new Langer Heinrich mine started up at the end of 2006.

In Niger the Akouta underground mine (since 1978) and Arlit open cut mine (opened 1971) are operated by Onarem, together producing 7.5% of the world's uranium.

In Gabon the Mounana mine was operated from 1982 to about 2000.

Mining and Processing

At Ranger and most of the Northern Saskatchewan mines through to McClean Lake the orebodies have been accessed by open cut mining. Olympic Dam, McArthur River and Jabiluka are underground, up to 600 metres deep, though there are plans to open cut the shallowest portion of Olympic Dam.

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 ion exchange.

Finally the uranium is recovered in a chemical precipitate which is filtered and dried to produce a uranium oxide concentrate, about 99% U 3 O 8 or over 80%U . It is then packed into 200 litre steel drums which are sealed for shipment. The U 3 O 8 is only mildly radioactive. (The radiation level one metre from a drum of freshly-processed U 3 O 8 is about half that - from cosmic rays - on a commercial jet flight.)

At an increasing number of mines in Australia, Kazakhstan and the USA mining is by 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 of uranium peroxide.

Wastes from Mining and Milling

Solid waste products from the 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 (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 most mines, tailings will be returned underground or they are emplaced in mined out pits. If this is not feasible they go to engineered dams.

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 Australian mines and many others 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.

Mining methods, tailings and run-off management and land rehabilitation are subject to Government regulation and inspection.

The Health of Workers

 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.

In Canada the Canadian Nuclear Safety Commission is responsible for regulating uranium mining as well as other aspects of the nuclear fuel cycle. In Saskatchewan, provincial regulations also apply concurrently, and set strict health standards for both miners and local people.

Uranium itself is only slightly radioactive. However, radon, a radioactive inert gas, is released to the atmosphere in very small quantities when the ore is mined and crushed. Radon is one of the decay products of uranium and radium, and occurs naturally in most rocks - minute traces of it are present in the air which we all breathe.

Open cut mines are naturally well ventilated. The Olympic Dam and Canadian underground mines are ventilated with powerful fans. Radon levels are kept at a very low and certainly safe level in uranium mines. (Radon in non-uranium mines also may need control by ventilation.)

Gamma radiation may also be a hazard to those working close to high-grade ores. It comes principally from radium in the ore, so exposure to this is regulated as required. In particular, dust is suppressed, since this represents the main potential exposure to alpha radiation as well as a gamma radiation hazard.

At the concentrations associated with uranium (and some mineral sands) mining, radioactivity is a potential health hazard. Precautions taken during the mining and milling of uranium ores to protect the health of the workers include:

At any mine, designated employees (those likely to be exposed to radiation or radioactive materials) are monitored for alpha radiation contamination and personal dosimeters are worn to measure exposure to gamma radiation. Routine monitoring of air, dust and surface contamination is undertaken.

Canadian mine and mill facilities are designed to handle safely ore grades of up to 26% U.

If uranium oxide is ingested it has a chemical toxicity similar to that of lead oxide. Similar hygiene precautions to those in a lead smelter are therefore taken when handling it in the drying and packing areas of the mill.

The usual radiation safeguards are applied at an ISL mining operation, despite the fact that most of the orebody's radioactivity remains well underground and there is hence minimal increase in radon release and no ore dust.

Safeguards to Prevent Military Use

Among uranium exporting countries Australia and Canada have some of the strictest conditions relating to the use of its uranium. These safeguards (inspections and accounting procedures) ensure that exported uranium 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 and Canadian Governments and each country wishing to import their 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 administered under the Nuclear Non-Proliferation Treaty.

The safeguards requirements under Australia's bilateral agreements, and similar ones with Canada, 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 the exporting country. 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 or Canada.

To investigate:

Updated March 2007