Relations between coal petrology and gas content in the Upper Newlands Seam, central Queensland, Australia

The Upper Newlands Seam in the northern Bowen Basin, Queensland, Australia consists of six benches (A-F) that have different petrographic assemblages. Benches C and E contain relatively abundant inertodetrinite and mineral ma tter, as well as anomalously high reflectance values; these characteristics support a largely allochthonous, detrital origin for the C and E benches. Fractures and cleats in the seam show a consistent orientation of northeast - southwest for face cleats, and a wide range of orientations for fractures . Cleat systems are well developed in bright bands, with poor continuity in the dull coal. Both maceral content and cleat character are suggested to i nfluence gas drainage in the Upper Newlands Seam. A pronounced positive cor relation between vitrinite abundance and gas desorption data suggests more efficient drainage from benches with abundant vitrinite. Conversely, inerti nite-rich benches are suggested to have less efficient drainage, and possib ly retain gas within pore spaces, which could increase the outburst potenti al of the coal. (C) 2001 Elsevier Science BN. All rights reserved.