Surat Basin

Etheridge and McInn (1986, p. 20) stated that the Purlawaugh Formation identified in well DM Bellata DDH 1, in the Gwydir subregion, is time equivalent to the Hutton Sandstone and Walloon Coal Measures (refer to Figure 19 of companion product 1.1.3 for the Gwydir subregion (Welsh et al., 2014)). The interval is 38 m thick comprising of a fluvial channel point-bar sequence overlain by a floodplain sequence of clay and sandstone. In coal boreholes DM Moema DDH 1 and 1A the same formation was identified although the report states that no coal company was interested in either hole (Bourke, 1977, p. 2). Deposits within this area represent an extension to the Hutton Sandstone and the Walloon Coal Measures which have been identified as ‘unit[s] that [are] considered to be a potential oil/gas reservoir’ (Etheridge and McInn, 1986, p. 20).

In northern NSW coals occur within the Bungil and Orallo formations, some of which are minor and unlikely to be economic targets; coal also occurs in the Walloon Coal Measures of the Surat Basin (Stewart and Alder, 1995, p. 158). Coal exploration has not been conducted for the Bungil and Orallo formations, and although the Walloon Coal Measures occur over a large area, their thickness, depth and lateral extent is not precisely known. The coals are considered to be high volatile bituminous rank and rich in vitrinite (Stewart and Alder, 1995, p. 158).

Last updated:
8 October 2018