Bismuth in the supergene environment

Abstract

Bismuth minerals associated with Mo, W, and Sn, are often found amongst the highly acidic deposits of the eastern ranges of Australia (Plimer, 1975; Weber et al., 1978). It is important to gain an understanding of the mobility and dispersion of Bi in the supergene zone and make an assessment of these areas, as they have been the focus for geochemical exploration to develop prospects and mining operations. A review of the literature on bismuth as a pathfinder element, with respect to its ground water and regolith concentrations, uncovered significant documentation including scientific, industrial and government reports, the use of various sampling methods, and the use of assumptions in previous studies due to the information and techniques available at the time (MacDuff, 1971; 1971a; 1971b; 1972; Siegal, 1974; Roes et al., 1979; Levinson, 1980; Plant et al., 1989; Plant et al., 1991; Fiella; 2010). Furthermore, information on the Gibbs free energy of formation values was limited to 3 out of the 65 known bismuth secondary minerals (Clissold, 2007). A study on a range of secondary bismuth minerals in the supergene zone, (Rankin et al., 2001, 2002; Sharpe and Williams, 2004) showed that even though bismuth minerals are considered to be rare, localised areas of Bi concentration are in fact quite common. Examples of this can be found in certain deposits in eastern Australia such as the New England Orogen. Therefore, the geochemical modelling carried out in this thesis has focused on eastern Australia and examines potential impacts on geochemical exploration where Bi has been used as a pathfinder element. Furthermore this work can be been applied to exploration sites around the world where Bi is employed as a pathfinder element. To do this, a rigorous investigation including Bi mineral synthesis, solubility and stabilities was undertaken thus yielding an assessment of the suitability of bismuth as a pathfinder for future geochemical surveys.

Date of Award	2015
Original language	English