The following article is excerpted from Uranium Mining in Australia, a booklet to be published in the near future by the Movement Against Uranium Mining. MAUM can be contacted at PO Box K133, Haymarket NSW 2000, phone (02) 212 4538.
No matter how uranium is mined, there will be radioactive contamination of the environment as well as noise, dust and sulphur dioxide fumes. Uranium tailings (or waste) constitute the greatest long-term threat, while leaks, spills and ground water problems are the major short to medium-terms concerns.
Uranium tailings contain 80% of the radioactivity of the original ore because they contain uranium decay products such as thorium and radium. They are also a major source of pollution because they are so easily dispersed by wind and rain and will require containment for hundreds of thousands of years. However, current uranium mill tailings containment arrangements cover usually no more than 200 to 500 years. Tailings piles have been left to collapse and pollute the surrounding area at Rum Jungle and Moline in the Northern Territory.
Mining and processing uranium consumes vast amounts of raw materials. For example, to produce 3596 tonnes of uranium oxide in 1988-89, Ranger used 4822 tonnes of pyrolusite, 41,217 tonnes of sulphuric acid, 17,311 tonnes of lime, 636 tonnes of ammonia, 625,050 litres of kerosene, and 17,662 litres of tertiary amine.
For each tonne of ore at Ranger, only three kilos of yellowcake are actually recovered. This leaves huge quantities of waste rock and low grade ore that are not milled, and millions of tonnes of tailings produced during the milling process. For an annual output of 3000 tonnes uranium oxide, Ranger will produce about a million tonnes of tailings. The tailings look like liquid mud, and are pumped into a tailings dam after being treated with lime to reduce the solubility of the heavy metals present.
Regulated releases of about two million cubic metres of contaminated water from Ranger each wet season carry radioactive radium and toxic pollutants including selenium, copper, lead, cadmium and arsenic down nearby Magela Creek and into the flood plain. After each successive wet season, radioactive wastes have become increasingly concentrated in plants, water and animals. This is made worse by the poor construction of the tailings dam which has been further weakened by periodic explosions, and also by the growing seepage of contaminated water caused by the rising ground water.
In addition, uranium mining and milling operations release great
quantities of radioactive radon gas into the atmosphere, as well as ammonia, nitrous oxide, sulphur dioxide and sulphuric acid mist which are known to kill plants and corrode rock faces. Mt Brockman near the Ranger mine has already suffered corrosion only a few years into the 30 year life-span of the mine.
The tailings pile at Roxby Downs contains waste from uranium and copper processing. It will be disposed of in layers and allowed to dry, known as "semi-dry" tailings disposal, a method criticised by the environment movement as likely to lead to higher radon releases than wet disposal. By March 1990, it contained two million tonnes.
ERA continued to deposit tailings under water until December 1986, when permission was given by the NT government to only partially submerge the tailings. In practice this has meant that islands of radioactive waste have appeared above the water level in the tailings dam. Attempts to plant trees on Ranger's tailings in 1988 failed when all the trees died during the wet season. As of June 1989, Ranger had accumulated 8.8 cubic million tonnes of tailings .
Between 1956 and 1972, mining at Moline created 246,000 tonnes of tailings. Within 10 years of the closure of the mill, the tailings dams collapsed, releasing 63,000 tonnes of tailings. When the Office of the Supervising Scientist (OSS) — established by the federal government to monitor the environmental impact of uranium mining in the Northern Territory — surveyed the site, it found significantly higher than normal levels of radioactivity in the flood plains of the creek below the mine and high concentrations of radionuclides up to 50 centimetres deep in the sediments of the flood plain, as well as high rates of continuing erosion from the tailings dam.
OSS also discovered radioactive and toxic seepage at the abandoned Rockhole mine near the El Sharana uranium mine in Kakadu's Stage III conservation zone. Rockhole operated between 1955 and 1962, producing 31,602 metric tonnes. A yellow-brown residue, mainly iron hydroxide, still flows from the abandoned mine site into Rockhole Creek and is highly acidic and kills fish.
Environmental health
A two-year preliminary study of Navajo Indians in the western US found an unusually high number of birth defects, including hydrocephaly, microcephaly, Downs syndrome, cleft lip, cleft palate, and epilepsy among more than 500 babies born between 1967 and 1974. Earlier surveys had found a serious increase in bone, ovarian and testicle cancers among children living in areas of former mining activity. The area around the Navajo Nation is marked by more than 350 abandoned open-cut uranium mines.
There has also been a significant increase in acute leukemia and chronic myelocytic leukemia between 1970 and 1976 in Grand Junction, Colorado, where uranium tailings were used in the construction of over 6000 homes, schools, shopping centres and footpaths.
According to calculations done in 1976 by Dr. Robert Pohl based on US Environmental Protection Agency figures, the expected radon releases from within a 3200 kilometre radius of a uranium tailings pile will cause about 400 deaths among the general population for each 1000 megawatts of electricity generated from uranium each year. [His calculations for coal came to 20 deaths per 1000 megawatts per year.] These deaths will be spread out over many thousands of years and much will depend on how effectively the tailings pile is sealed and how long it stays that way.
In former East Germany where uranium was mined from 1946 for the Soviet weapons program, the situation is, if anything, worse. Tailings piles at Erzgebirge are like "mountains that extend over several kilometres", whose radium-containing dust blows over farmland and whose radium has leached into the ground. There seems to be little or no protection for these tailings piles and no attempt at reclamation. Dust from sludge settling basins is so great that local villagers experience a burning sensation in the mouth and nose on windy days. Authorities have refused to take measures against the dust. The contamination of ground water and the local water supply is an increasing problem. As in the US during the 1950s, tailings have been used for footpaths, roads and house construction.
The milling plant at Port Pirie in South Australia produced yellowcake from the ore mined at Radium Hill until the mid-1960s. Today, a tailings dam and derelict tanks remain on the very edge of town. Washed by high tides and eroded by winds are 200,000 tonnes of tailings. Very recently and after much public protest, the authorities grudgingly fenced off the area. Children had played and swum in the dams for years.
Workers
It's been known since 1920 that uranium miners suffer high mortality from lung cancer caused by exposure to radioactive radon gas during their work. Radon, which decays from radium 226, is an inert gas, heavier than air, with a half-life of about one week. When inhaled, radon gas and its decay products lodge easily in the human lung, emitting energetic alpha particles which affect the vulnerable layer of cells lining the fine tubes in the lung.
Between 1920 and 1957, as new evidence came to light from Hiroshima and Nagasaki, radiation protection authorities revised the maximum permitted radiation dose drastically downwards. However, since then, despite even more evidence that the current dose is too high,
authorities remain reluctant to change the standard. In 1980, the US National Institute for Occupational Safety and Health (NIOSH) found "a clear indication that cumulative exposure to radon and its decay products is associated with an increased risk of lung cancer".
NIOSH has criticised the current standard of exposure as having "no margin of safety" and wants — or wanted, until former President Reagan abolished it — to see the permissible exposure limits for all uranium and nuclear workers reduced to one tenth the current level. According to an 1980 NIOSH study, there was a two to four times greater risk of death from lung cancer among uranium mining workers compared with estimates made ten years earlier, even if they were exposed only to radon within the then current standards.
A 1982 report for the Atomic Energy Control Board (AECB) of Canada suggested that the result of a 50-year occupational exposure to the current standard would be 130 excess lung cancers per 1000 people. The AECB ignored the study, and instead wanted to raise the limit for alpha radiation to which workers could be exposed.
In East Germany, although the evidence is anecdotal and statistics are not available, miners at the Wismut mines suffer high rates of testicle and lung cancer and impotence. There is also a higher than expected incidence of leukemia, loss of hair and miscarriages amongst local residents, and mental and physical handicaps amongst children.
Closer to home, a study done of the Register of Deaths shows that 40% of those who worked underground at the Radium Hill mine in South Australia have died of lung cancer.
Exposure to radiation amongst both miners and plant workers has become an issue at Roxby Downs, where miners are being exposed to radiation levels higher than those at Ranger and Nabarlek.