<P> Radioactive ores were first extracted at Radium Hill in 1906, and Mount Painter in South Australia in the 1930s, to recover radium for medical use . Several hundred kilograms of uranium were also produced . Of the world's proven estimated uranium reserves (5,404,000 tonnes), 31% are held in Australia (1,673,000 tonnes), ahead of the second largest, Kazakhstan (12.1% or 651,800 tonnes). In terms of production, Canada is the largest supplier to export markets, followed by Kazakhstan and Australia . Uranium mined in Australia is mainly for export . Australia exported 50,235 tonnes of uranium oxide concentrate in the five years to 2008, worth A $2.9 billion . </P> <P> Following the Japanese Fukushima nuclear disaster in early 2011, many countries are scaling back their nuclear power production, with some setting deadlines for a complete shutdown of all nuclear power reactors . It is expected that this may impact on demand for Australian Uranium . However, State governments have now approved mine development in Western Australia and Queensland . But as of 2013 uranium prices are very low, and it is unlikely that any new projects will enter active development until the market improves . </P>

How much of the world's uranium does australia have