, at 25 °C in 0.100 mol dm -3 aqueous HNO 3 was also investigated. Equilibrium dissolved Sb concentrations were 3.3 ± 1.0 × 10 -7 and 7.7 ± 2.1 × 10 -8 mol dm -3 , respectively. These values have been used to re-evaluate the geochemical mobility of Sb in the supergene environment. It is concluded that the element is geochemically immobile in solution and in soils. This was in part validated by an orientation soil geochemical survey over the Bayley Park prospect near Armidale, New South Wales, Australia. Anomalous soil Sb levels are confined to within 100 m of known stibnite mineralization.