Resources and geology of Australia's thorium deposits

Australia's thorium resources currently amount to 452,000tonnes Th of which 364,000tonnes (80.5%) occur in heavy mineral sand deposits, 53,300tonnes (11.7%) in a vein type deposit at Nolans Bore in the Northern Territory and another 35,000tonnes (7.7%) are in an alkaline trachyte plug at Toongi in New South Wales. This distribution of thorium resources differs from the world wide distribution where 31.3% of the resources occur in carbonatites, 24.6% are in placers, 21.4% in vein type deposits and 18.4% in alkaline rocks. This variance is at least partly due to relatively more, although still inadequate, data on thorium resources being generated by the very active heavy mineral sand operations around Australia. Even where thorium analyses have been carried out for other types of deposits that host thorium, such results are not published since thorium is not considered to be economically important. All of Australia's thorium resources occur in multi-commodity deposits, dominantly the heavy mineral sands and in rare earth deposits where the extraction cost would be shared with if not totally supported by the other commodities in the deposit. Because there has been no large-scale demand for thorium, there has been little incentive for companies to assess the cost for the extraction of thorium resources. Hence there is insufficient information to determine how much of Australia's thorium resources are economic for purposes of electricity power generation in thorium nuclear reactors. Geoscience Australia is currently engaged in upgrading its database on thorium resources as part of the five-year Onshore Energy Security Program and Australia's figures on its thorium resources will be refined as a result of this work. Because of limited demand, there has been very little exploration for thorium in Australia. As part of its five year Onshore Energy Security Program, Geoscience Australia is in process of upgrading its continent wide airborne radiometric coverage and is conducting a low density geochemical sampling program across the continent. These programs will help to develop a better understanding of the geological and geochemical environment of thorium in Australia and provide basic pre-competitive data to reduce risk the level of risk for the mineral exploration industry. Assessment of thorium resources by the minerals industry in the future will depend upon the development of commercial-scale thorium nuclear reactors and the resulting demand for thorium resources.