What is uranium?
Uranium is the heaviest of all minerals. It was first isolated in 1841, although its origin is in the formation of the universe. The earth’s crust contains an average of about 3 ppm (= 3 grams per tonne) uranium, and seawater approximately 3 ppb (= 3 mg/t) (WISE 2006).
The amount of uranium in ore is always quite small, averaging 0.3% in Australia but as high as 15% in Canada. So the ore must be milled to concentrate the uranium. The resulting product, uranium oxide (U308) is called ‘yellowcake’ because it is sometimes that colour.
Naturally occurring uranium contains three main isotopes, all of which are radioactive: U238, U235, and U234, although 99% of the U found in yellowcake is U238. Because yellowcake contains the three commercially useful isotopes, it is radioactive. Uranium isotopes remain radioactive for a long time – indeed millions of years: U238 has a half-life (the time it takes for it to lose half its radioactivity) of 4.5 billion years, U235 704 million years, and U234 245 thousand years.
Uranium occurs naturally all over the world and as a result contributes to what is called ‘background’ radiation. Radon is a radioactive gas released from the decay of uranium. Uranium and thorium are the main sources of background radiation, which averages 2mSv
in Australia (ARPANSA 2003).
Where could uranium be mined in Queensland?
Despite the current ban on uranium mining in Queensland, both labor and coalition governments have allowed exploration by mining companies.
There are literally thousands of sites being explored all over the state, but the bulk of them are in the northern half of the state.
How is uranium mined?
In Australia three kinds of mining process are used to extract uranium: underground (as used at Olympic Dam), surface (open pit, as used at Mary Kathleen), or solution/in-situ leach, (as used at Beverley). All pose risks to environment and human health, especially wit respect to water.
What is underground mining?
Tunnel mining, despite being less visible than other types of mining, poses risk to both human health and environment. Besides the obvious risk regarding collapse and air quality in underground operations, uranium mines present a dangerous scenario for workers due to exposure to radon gas and uranium dust. Subsidence, pot holes, fissure an other surface openings occur and disruption and contamination of groundwater and acid mine drainage also occur.
What is open cut mining?
The most environmentally visible of the types of mining used for uranium, open cut is basically a massive pit cut into the surface of the earth extracting everything in it’s path. Open cut mining also allows more dust and particles to escape into the local atmosphere, although their outdoors nature may reduce the exposure to radon gas of workers. Open cut mines are notoriously difficult to rehabilitate due to the sheer quantity of earth removed.
What is in-situ leach mining?
The most contentious type of uranium mining, in-situ leach (ISL) involves injecting huge quantities of water and sulphuric acid into the deposit or the aquifer in which the deposit occurs, and sucking the resulting slurry out for separation.
The potential for ground and surface water contamination is far greater than other types of mining, as blockages in pipes can cause leachate to flow out of control (as occurred during a trial at Honeymoon, SA). The pumping process may also release large quantities of radon gas into the atmosphere, risking workers. However, the risk to workers inhaling uranium dust may be less.
What happens after the mining ceases?
Uranium mines remain dangerous after closure. One of the enduring problems everywhere is the clean up afterwards. Mining companies rarely seems to save enough money for the task.
US state agency representatives estimated in 2004 that an open pit copper mine in New Mexico would cost more than US$800m to clean up. In July 2005 Energy Resources Australia (ERA), operators of the NT’s Ranger mine, revealed in their half-yearly report that they had put aside just $41m to remediate the site which is surrounded by Kakadu National Park. ERA say it will cost closer to $176m to clean up the site when the mine closes in 2008, the rest may have to be met by the state.
When Mary Kathleen mine in Queensland closed in 1982, it had produced about 3500 times more rock waste than it turned into yellowcake and left a massive conical hole 4km wide at the top and 250m deep. Shortages in the MK remediation fund meant that they took shortcuts when sealing in tailings. Instead of using clay, they used a combination of clay and radioactive rock from the mine site itself.
In 2004, State Member for Mt Isa, Tony McGrady expressed concern that people were swimming in Mary Kathleen tailings
dam, risking radiation contamination (FoEB 2006).
What does uranium milling entail?
Left: tailings dams at Olympic Dam, SA. After extraction, uranium must be separated from the other minerals in the deposit. This is done by crushing and leaching the rock using water and (usually) sulfuric acid. The leaching process also separates out other minerals including molybdenum, vanadium, selenium, iron, lead and arsenic, requiring a second separation to remove the uranium.
This process uses enormous amounts of water which is contaminated with acid and the unwanted minerals and leftover uranium, and containing long lived decay products such as thorium230 and radium226. It is left in tailings dams, ostensibly because the waste is safer and less likely to dust disperse when inundated. The sludge that tailing water covers is 85% as radioactive as the uranium extracted and it continues to release radon. Tailings dams all over the world have had leakage problems and there are many documented instances of increased exposure to radiation in people living downstream from these tailings dams through consuming contaminated water, fish and crops. In 2004 Olympic Dam uranium mine reported a leak from their tailings dams system that had gone unnoticed for several years. In addition, local wildlife have been killed by drinking the tailings water.
After milling, uranium is transported out of Australia for enrichment into a state suitable for weapons manufacture and energy use.
Risks to miners
“Over the years the permitted levels of radiation exposure for workers and the public have dropped dramatically as research, particularly from radiation biologists, indicates harmful effects still exist at much lower exposure levels. For workers, the permitted dose was set at 500 millisieverts per year in 1934, 150 mSv in 1950, 50 mSv in 1956, and 20 mSv (averaged over five years) in 1991. The limit for members of the public is just 1 mSv….the European Committee on Radiation Risk, comprising 30 independent scientists, released a report which concluded that the total ermissible dose to members of the public from all human practices should be reduced to no more than 0.1 mSv (a ten-fold reduction), with a limit of 5 mSv for nuclear workers (a four-fold reduction).” (2006: FoEA. The Push to Expand Uranium Mining)
In March 2004 workers at ERA’s Ranger mine in the Northern Territory were accidentally poisoned with radioactive water, the extent of which they only discovered after reading the newspapers, not from their employers. Workers drank and bathed in the radioactive water. A Commonwealth-appointed scientist Arthur Johnston commented to media that ERA had become complacent about radiation dangers at the Ranger mine and did not provide enough protection for workers.
For more detailed information on uranium health effects see our fact sheet: “Uranium and your health” (opens pdf file)
Indigenous rights and uranium mining
The indigenous people of Australia are under pressure from mining companies to permit mining on their sacred lands, sometimes in exchange for basic services like school and hospital that they should already have and royalties are often an enticement in areas where poverty and lack of services prevail due government neglect. These conflicts can cause rifts in the community.
The health and environmental effects are felt in many mining communities worldwide to varying degrees, the Navajo homelands region of the US being a notable example where residents experience lung cancer rates and over half of groundwater is contaminated by defunct uranium mines. The effect on the community has been so dire than in 2005 the Navajo elders signed the first ever tribal law banning uranium mining (SRIC 2005).
Besides the resumption and contamination of indigenous lands the greed of mining companies and governments can lead to corruption and worse. In 2005 a Gansu (China) uranium mine employee went missing after attempting to report the severe radiation poisoning affecting local residents. “residents near and downstream of the plant have begun suffering a high incidence of cancerous tumors, leukemia, birth defects, miscarriages and other unusual afflictions. …Local medical workers report that nearly half of all deaths in the area are from some form of cancer, but patients’ case histories are routinely altered because of “state secrets” concerns” (HRIC 2005).
It’s no coincidence that the most socially disadvantaged group in Australia are now having a nuclear waste dump foisted apon them. To find out more about the Muckaty High Level Nuclear Waste Dump check out http://foe.org.au/anti-nuclear/issues/oz/nontdump/
Why is uranium mined? What is it used for?
Uses include: colouring glass, counterweights in elevators and airplanes, ballast for space missile reentry, smoke detectors, food ‘sterilisation’, industrial filling instruments, reflective paint on clock faces, xrays, medical treatments, nuclear power and nuclear weapons. All of these uses can be replaced with other technology. Indeed a 2006 report showed that in one seemingly vital use, in smoke alarms, light activated alarms worked faster than radioactive alarms.