Uranium mining in Australia: Environmental impact, radiation releases and rehabilitation

The mining and export of uranium and the impacts (and risks) of the nuclear industry have long been a contentious issue in Australia. The ongoing debate primarily relates to the established and potential dangers of ionizing radiation released to the environment from nuclear facilities, such as uranium mines or research reactors. By 2002, three uranium milling projects are operating with a further seven having been operated in the past 50 years, including numerous smaller mines. A critical aspect of the operation of a mine and/or mill is the ionizing radiation rates before, during and after a project has ceased. A number of estimates have previously been made of the environmental releases from Australian projects, such as environmental impact statements and the UNSCEAR 1993 data (although there is some controversy as to the quality of the data and assumptions used in this analysis). In order to assess the environmental impacts of ionizing radiation releases from nuclear facilities, such as radon gas or soil and water quality, it is necessary to compile and quantify these changes based on measured data from the various sites around Australia. This paper presents a brief review, based on more comprehensive studies in progress, of the changes in ionizing radiation rates, radionuclide releases and ongoing issues from some operational and former uranium projects in Australia, allowing a more accurate assessment of the measures required for protection of the environment from potentially harmful situations. The importance of detailed field radiation measurements before, during and after rehabilitation is stressed, followed by a discussion of Non-Government Organisation (NGO) views of the implications for uranium mining and milling. 1. URANIUM MINING AND MILLING IN AUSTRALIA The history of uranium mining and milling in Australia spans the 20 century, beginning with radium mining in the early years and expanding to large scale uranium projects over the last 50 years (Figure 1). The first uranium deposits in Australia were discovered at Radium Hill and Mt Painter in north-eastern South Australia in 1906 and 1910, respectively. Between 1906 to 1932 intermittent mining and milling occurred to extract radium with uranium as a by-product, based on mining of ~3,200 t of ore (0.2–20% U3O8) giving ~1.8 g of radium and up to 7 t U3O8 [1]. The various sites were abandoned by 1932, including the radium refineries at Hunters Hill in Sydney, NSW, and at Dry Creek in Adelaide, SA. A new phase of uranium exploration was begun for the Manhattan Project over 1944–45 (World War II), with extensive exploration undertaken by governments, prospectors and mining companies following the war with a view to securing uranium for nuclear weapons and reactor programs. By the late 1950s, there were six uranium mills operating in the Northern Territory, South Australia and Queensland, supported by numerous smaller uranium mines. This phase ended with the closure of Rum Jungle in 1971 following the total production of ~2,500 t U3O8 for nuclear weapons programs of the USA and UK, 4,800 t U3O8 for the UK’s nuclear reactor program, plus a national stockpile of ~2,100 t U3O8 [1]. The environmental management of these sites was generally poor or minimal. The late 1960s saw the eventual emergence of nuclear reactors on a commercial scale and a rapid increase in the intensity of uranium exploration across Australia. The success was virtually instant and by the early 1970s new uranium provinces had been identified in the Alligator Rivers Region of the NT, central Western Australia as well as other uranium deposits of varying significance. The 1970s coincided with increasing public knowledge and debate about the impacts of the nuclear industry, centred around nuclear weapons, reactor safety, intractable nuclear waste and the dangers of ionizing radiation. Further concerns included indigenous land rights and environmental conservation.