The Early Permian aged sequence of the Alum Mountain Volcanics (Figure 3 and Figure 4) has four discrete members, including one coal member (Clareval Coal Member). According to Hughes (1995, p. 418) the Alum Mountain Volcanics (also referred to as the Stroud Volcanics by Hughes (1995, p. 418) and Brakel (1989, p. 59)) is coal-barren, although Roberts et al. (1991, p. 164) notes the presence of a basal coal measure sequence with a fine pebble conglomerate overlain by a thick, deformed coal seam in the south. The presence of two correlatable coal seams, namely the Basal and Clareval coal members, are noted in stratigraphic columns in AGL Energy Limited (2009) and SRK Consulting (2010, p. 9). Roberts et al. (1991, p. 164) mentions that the coal seam in the Alum Mountain Volcanics contains shale and conglomerate lenses, but little is known about the coal quality, thickness or distribution of coals in this formation. According to Australasian Groundwater and Environment (AGE) (AGE, 2013, p. 4–34) coal is extracted from the Clareval Coal Member (Figure 2) at Duralie Coal Mine in the south of the Gloucester Basin.