About Uranium Uranium Mining: Uranium Mining in Canada In the last forty 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 two 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. 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. 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 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 most of Canada's Northern Saskatchewan mines through to McClean Lake, the orebodies have been accessed by open cut mining. Other mines such as McArthur River, Rabbit Lake and Cigar Lake in Northern Saskatchewan 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 Over half of the world's uranium now comes from underground mines, about 27% from open cut mines and 19% from ISL. Conventional mines have a mill where the ore is crushed, ground and then 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. 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. Uranium in Canada 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 in five districts. 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 world uranium resources is about 15%, but it produces about one third of the mined uranium. Other countries with major uranium deposits are Kazakhstan, South Africa, Namibia, Brazil, Russian Federation and the USA. Table 1 Known Recoverable Resources of Uranium   tonnes U3O8 percent of world Australia 863,000 28% Kazakhstan 472,000 15% Canada 437,000 14% South Africa 298,000 10% Namibia 235,000 8% Brazil 197,000 6% Russian Fed. 131,000 4% USA 104,000 3% Uzbekistan 103,000 3%       World total 3,107,000   Reasonably Assured Resources plus Estimated Additional Resources - category 1, to US$ 80/kg U, at 1/1/99. Brazil, Kazakhstan and Russian figures above are 75% of in situ totals. Uranium: Resources, Production and Demand 1999, OECD NEA & IAEA, July 2000. Canada's uranium mines Canada is in the midst of 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 still has some reserves at Eagle Point, where mining has resumed. Cogema Resources operates the McClean Lake mine, which started production in mid 1999. Its Cluff Lake mine has now closed, and will be decommissioned in 2003. The McClean Lake mine commenced operation in mid 1999. It is producing about 3000 t/yr U3O8 from 2.4% ore but has been relicensed for 3640 t/yr. 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. It is owned by Cogema Resources (70%, also operator), in joint venture with Denison Energy (22.5%) and OURD (7.5%). McArthur River has enormous high-grade (23%) reserves at a depth of c 600 metres. It opened at the end of 1999. 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 8200 t/yr of U3O8. Tailings are deposited in a mined-out pit. Cameco is the operator and majority owner, with Cogema (30.2%) as partner. There are also two further new uranium projects coming into production in the next few years in N. Saskatchewan. Cameco's Cigar Lake is planned as a 450 m deep underground mine in poor ground conditions, using ground freezing and high-pressure water jets for excavation of ore. High-grade (22.5%) ore from remote mining will be trucked for treatment at the expanded McClean Lake mill, 80 km northeast, and to Rabbit Lake mill 70 km east, to produce 8200 t/yr U3O8. Government approval was received in 1998, but start-up has been deferred to at least 2006. Cogema'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 2600 t/yr U3O8. Government approval received in 1998 enabled application for CNSC construction and operating licences. Table 3 Summary of Resources Available in Operating and Planned Canadian Uranium Mines mine operator tonnesU3O8 av. ore grade category Key Lake Cameco 450 0.41% proven reserves Rabbit Lake Cameco 10,150 1.30% proven reserves     900 0.88% indicated resources Cluff Lake Cogema 5,400 1.2% "resources /reserves" McClean Lake Cogema 21,800 2.4% "resources /reserves" McArthur River Cameco 161,300 21.0% proven reserves     17,700 23.04% probable reserves     66,000 10.74% indicated resources Cigar Lake Cameco 102,670 19.77% proven reserves     2,440 4.2% probable reserves     53,600 16.95 inferred resources Midwest Cogema 16,300 4.5% "resources /reserves" Dawn Lake Cameco 5,800 1.69% indicated resources Mining and Processing At most of the Northern Saskatchewan mines through to McClean Lake the orebodies have been accessed by open cut mining. 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% U3O8. 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.) 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 Ranger and Jabiluka, tailings will be returned underground, as was done at the now-rehabilitated Nabarlek mine. In Canada ore treatment is often remote from the mine, and tailings are emplaced in mined out pits wherever possible and engineered dams otherwise. 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. 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 Miners 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 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. At the relatively high concentrations associated with uranium (and some mineral sands) mining however, radon 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:   Efficient dust control, because the dust may contain radioactive constituents and emit radon gas. Limiting the radiation exposure of workers in mine, mill and tailings areas so that it is as low as possible, and in any event does not exceed the allowable dose limits set by the Health Code. In Canada this means that mining in very high-grade ore is undertaken solely by remote control techniques. The use of radiation detection equipment in all mines. Good forced ventilation systems in underground mines to ensure that exposure to radon gas and its radioactive daughter products is as low as possible and does not exceed established safety levels. Imposition of strict personal hygiene standards for workers handling uranium oxide concentrate. 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. Government Policy: Canada In 1944, an engineering design team was brought together in Montreal, Quebec, to develop a heavy water moderated nuclear reactor. The National Research Experimental reactor (NRX) was built at Chalk River , Ontario, and started up in 1947. It provided the basis for Canada's development of the very successful CANDU series of power reactors, and served as one of the most valuable research reactors in the world. Also in 1944, the federal government took over the Eldorado company (hitherto mining radium) and formed a new Crown corporation which later became Eldorado Nuclear Ltd. Uranium exploration was restricted to the joint efforts of Eldorado and the Geological Survey of Canada until 1947. In the late 1970s the Saskatchewan Mining Development Corporation, a provincial crown corporation, had taken a 20% interest in the Cluff Lake development and a 50% interest in Key Lake. In 1988 this merged with Eldorado Nuclear Ltd to form Cameco Corporation, now the world's leading uranium producer. In 1991 Cameco made its first public share issue. The Canadian and Saskatchewan governments have adopted a policy of supporting uranium mining where it can be demonstrated to be environmentally acceptable. In 1991 a Joint Federal-Provincial Environmental Assessment and Review Panel was formed to study the health, safety, environmental and socio-economic impacts of five proposed uranium mining developments in northern Saskatchewan. A Federal Panel was formed to examine a sixth proposal. Expansions at the Cluff Lake and Rabbit Lake operations were reviewed and approved in 1993, and came into operation. Safeguards to Prevent Military Use Among uranium exporters,  Canada has 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 Canadian Government 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.