Factsheet on uranium
Top Ten Uranium Mines
Sites of Uranium Mines for Weapons Programs (world map)

From the time of its discovery in 1789 to the early 1900s uranium was used for color and glazing in ceramics and glass-making.¹ From the early 1900s to the late 1930s, it was discarded as a waste from radium production (which was used in medical applications and to make instrument and watch dials luminous). Though found throughout the world in trace quantities, uranium is often mined where concentrations are 0.1 to 0.5 percent of ore. On rare occasions it can be found in concentrations over 10 percent, such as in the Saskatchewan reserves of Canada, or even greater. There are four common methods for mining:

• open pit;
• underground;
• in situ leach mining which consists of injecting solvents such as hydrochloric acid, alkaline carbonate and hydrogen peroxide underground to dissolve the uranium from the ore body. Waste solutions are pumped back into the ground; and
• heap leaching, which is used to recover uranium as a by-product from extremely low-grade ores resulting from gold and phosphate mining. This process involves repeatedly percolating a leachate solution (typically sulfuric acid or ammonium carbonate) through an ore pile to dissolve uranium, until its content in the solution becomes high enough for extraction.

Uranium milling consists of extracting the uranium from the ore and processing it into an oxide powder that can be shipped. Both the mining and milling process expose the workers, nearby residents and the environment to various hazards. To understand these it is first necessary to understand the make-up of uranium ore.

Natural uranium consists of three alpha-emitting isotopes: U-238, U-235 and U-234. These isotopes also emit some gamma radiation. U-238, the most prevalent of these isotopes (almost 99.3 percent in natural uranium) has a half life of about 4.5 billion years. The half lives of U-235 (about 0.7 percent) and U-234 (which is only 0.005 percent of content but accounts for almost half of uranium's radiation) are 704 million years and 245,000 years respectively. Decay of uranium-238 gives rise to many radioactive decay products, including thorium-234 and -230, radium-226, radon-222 and polonium-218 and -214. These decay products are always found together with natural uranium in ores.

Uranium is both radioactive and a chemical toxin. Outside the body, natural uranium poses only a slight hazard because of its relatively weak gamma ray emissions (unless exposure is prolonged). Once inhaled or ingested, it can increase the risks of lung and bone cancer due to its alpha emissions. The decay products of uranium-238 pose additional health hazards. Thorium-234 decays in place while thorium-230 tends to be taken up in the bone. Polonium is distributed in soft tissues as well as bone. Radium is similar to calcium and accumulates on the surface of the bones and later in the matrix of bone structure. Radium is dangerous when ingested. It is a known agent of bone cancer as was discovered in the 1920s through the unfortunate fate of the radium dial painters who inadvertently ingested radium when licking the tips of their brushes to produce a fine point.

The gas radon-222 is a decay product of radium-226, and has a half life of 3.82 days. Radon and its decay products are historically responsible for the elevated levels of lung cancer incurred by uranium miners. Conventional underground mining is most dangerous to workers because of higher exposure to radon decay products. Workers breathe in the polonium-218, lead-214, bismuth-214 and polonium-214 in the air. The decay of these radionuclides in the lung has been the chief route of exposure of uranium miners and is historically responsible for the elevated levels of cancer they incur. Exposure to radon and its decay products is measured in working levels and working level months (see Radiation Doses).

Uranium miners also face many non-radiation-related hazards. Soluble uranium affects the kidneys if ingested or inhaled because of its chemical toxicity as a heavy metal. The ore in which uranium is found also contains non-radioactive toxic heavy metals. These vary from site to site but may include arsenic, lead, molybdenum, and manganese. Silica dust is created in the drilling process and can cause the gradual development of scarring of the lungs, which restricts lung function and can lead to cancer and an increased risk of tuberculosis, rheumatoid arthritis and kidney disease. As with all types of mining, uranium miners face a high risk of injury; however, these risks have declined in most countries over the years as safety measures have improved.

Doses to workers in uranium mines can be reduced through proper ventilation,careful planning, and good design and work practices. Yet, many mine operators throughout the world have resisted steps to ameliorate working conditions. For instance, it took the U. S. until the mid 1960s to establish protections against known health hazards, even though studies conducted by the United States Public Health Service (USPHS) in the early 1950s showed that hazards to American workers were similar to those in Europe, where elevated levels of lung cancer had already been demonstrated. Canada promted by the U.S. race for the bomb, began mining and processing on a large scale in the 1940s. There was no regulatory upper limit to radiation exposure for Canadian miners until 1968. The Soviet Union operated its East German mines with no radiation protection measures until 1954; they continued to be a radioactive disaster area for decades. Worker health and safety has been neglected at Namibia's Rössing mine as well. For the first three years of operation it wasn't compulsory for workers to wear film badges and then only in the final stages of uranium extraction. A 1992 study found that, "throughout [the 1980s] the Rössing industrial hygiene standard for airborne uranium was nearly 6 times the ICRP [recommended maximum] Derived Air Concentration for natural uranium, and 36 times the limit implied by current scientific evidence."²

A number of health studies of uranium miners have been conducted, documenting elevated levels of lung cancer. In Czechoslovakia, follow-up studies on several cohorts of miners have been conducted since 1970. A study of 4042 miners who began working underground between 1948 and 1957 found that the number of lung cancer deaths as of 1985 was five times the expected number.³ In Canada an Ontario study examining data from 1955 to 1986 on 50,201 miners (including 15,000 miners who worked exclusively in Ontario uranium mines) discovered an excess of 120 lung cancer deaths over the 171.8 expected in the non-exposed population. In the United States numerous follow-up studies have been conducted on the USPHS cohort. A 1988 study by Hornung and Meinhardt suggested synergistic effects of cigarette smoking and exposure to radon decay products. Lung cancer deaths in excess of those expected have also been found in studies of Australian, East German, and French miners. Information about the health and environmental effects in many regions, like Africa, the former Soviet Union, and China is not easily available, and fewer studies have been conducted in these regions.

Waste from the milling process, which involves the chemical separation of uranium from other ore components, also poses significant health and environmental hazards. For a typical uranium concentration of 0.2 percent, 1,000 metric tons of ore are needed in order to get 2 metric tons of uranium, leaving behind 998 tons of waste. This waste, called mill tailings, contains 85 percent of the radioactivity in the original ore along with heavy metals and chemical toxic materials from mill reagents such as sulfuric acid and ammonium chloride.

When discharged from the mill, the tailings are roughly 40 percent solids and 60 percent liquid. The liquid can eventually percolate into the soil, posing a threat of ground water contamination. Wind scatters fine respirable radioactive particles from dry tailings areas, exposing workers and nearby residents. Mill tailings have also been frequently used in construction of houses, leading to high radon doses to inhabitants. Mill tailings make up over 95 percent of the total volume of radioactive wastes coming from the nuclear fuel cycle (excluding mine waste), and are very long-lived (although account only a small fraction of the radioactivity).

In the early decades, mill tailings were left in unlined tailings ponds, leading to contamination of groundwater. Tailings dams have ruptured, leading to release of impounded tailings discharges and widespread contamination. In 1979, a United Nuclear uranium mill tailings dam broke near Churchrock, New Mexico, releasing 94 million gallons of tailings liquids and 1,100 tons of tailings solids which spread 60 miles from the facility. In the Elliot Lake area of Ontario, Canada 80 kilometers of the Serpent River system including 10 local lakes have been contaminated. Elliot Lake has also experienced 30 tailings dam breathings and 125 radioactive spills in Saskatchewan have been reported. In the United States, tailings areas are being remediated by putting plastic liners under the tailings to prevent seepage and by keeping them under water to reduce emissions of radon decay products.

The burden from the effects of uranium production, driven by a few countries seeking nuclear weapons and nuclear power has been disproportionately carried by indigenous, colonized and other dominated peoples. Approximately two-thirds of the United States' uranium deposits are on Native American land and almost a third of all mill tailings produced in the U.S. from abandoned mill operations are on Navajo land. Northern Saskatchewan, home to some of the richest reserves, and where over 20% of uranium in the world is mined, is inhabited by the Cree and Dene.

Much of the uranium used in French weapons and reactors has been mined in Niger and Gabon. Although the mines are run by the French company Cogema, they are not subject to the same health and environmental regulations that are enforced in France. The conditions in Niger prompted BBC producer Chris Olgiati to remark: "Some of the poorest people on earth labor in one of the deadliest environments to power the electric train sets and fuel the bombs of the world's richest nations."⁴ Other European states and Japan also buy uranium from Niger and Gabon. The British company Rio Tinto Zinc began mining operations in Namibia, at Rössing in 1976 in violation of a 1974 UN decree that no Namibian natural resources could be extracted without the consent of the UN Council for Namibia. Until 1990, Namibia was a colony of South Africa. A significant amount of this uranium went to facilitate Britain's nuclear weapons program and Japan's civilian nuclear power operations.

In most countries, uranium mining has been the most hazardous step of nuclear materials production, both in terms of doses and in the number of people affected. Greater efforts are needed to identify populations affected by uranium mining and milling activities, to assess the extent to their exposures, and provide them with health monitoring and related assistance. Countries should protect both uranium miners and those living nearby mining and milling sites by establishing standards based on the recommendations of the International Committee on Radiological Protection (2 rem maximum worker exposure per year). Given the disproportionate burden born by non-nuclear countries and dominated peoples, they should be provided adequate health and environmental monitoring, environmental remediation of damaged areas, and compensation for past injustices in order to redress the manifest inequity of the pollution.

Factsheet on uranium
Top Ten Uranium Mines
Sites of Uranium Mines for Weapons Programs (world map)