Uranium minerals from Mt Painter, northern Flinders Ranges, South Australia

Abstract

The Mt Painter uranium field, located in the northern part of the Flinders Ranges, is famous as a source of well-crystallized torbernite and autunite specimens. From its discovery in 1910 to the mid-1930s, the field was worked intermittently for radium. Intense activity came again in the year 1944, as part of the urgent requirement to provide uranium for Allied nuclear research. The intensive exploration program continued until 1950 with the support of the south Australian Government. However, no high-grade resource was discovered. Uranium mineralization at Mt Painter is hosted by brecciated Proterozoic granites and is probably of Late Ordovician age. The breccias also contain hematite-rich lenses. One of these lenses, exploited by the No.2 workings, contains a complex assemblage of primary U-REE-Nb minerals including monazite-(Ce), xenotime-(Y), ishikawaite-Fe-rich samarskite solid solution, and an unidentified U-Pb-Mn-rich phase. Secondary U-minerals reported from the No.2 workings include billietite, boltwoodite, Ce-rich françoisite-(Nd), schoepite and metaschoepite, soddyite, meta-torbernite, uranophane-βand weeksite, as well as spriggite, a new hydrated lead uranyl oxy-hydroxide named in honour of Reg Sprigg, geologist and founder of the Arkaroola Tourist Resort on which the type locality is located.