In recent years there has been significant development in the field of coalbed and coal mine methane drainage and
utilisation in Australia. This development has, in part, been necessitated by the rapid increase in mine production capacity
and the need to maintain the safety of the mine and its employees through effective management of coal seam gas emission and outburst risk. The increased awareness of the contribution of coal mine gas emission, estimated to account for 4-5% of Australia’s 559 million tonnes of CO2 equivalent (MtCO2-e) annual greenhouse gas (GHG) emissions, is placing additional pressure on operators to increase coal seam gas capture and emissions reduction measures.
This paper discusses the various sources of gas emission from an operating underground coal mine, with particular focus on longwall mining which accounts for the majority of Australian underground coal production. A variety of gas drainage
techniques, both from surface and from within operating underground mines, are described along with a range of
commonly encountered problems that exist within coal mine gas drainage systems that prevent optimum drainage
performance being achieved. Two variations of a new surface-based gas drainage system for the removal of goaf gas to
improve longwall mine productivity and safety are described. This proposed new technique aims to cost effectively
increase the total gas volume extracted from the goaf whilst maintaining a relatively consistent gas production rate
throughout the operating life of the well. Various methods of coal mine methane gas utilisation are examined, including the
capture and utilisation of low concentration methane present in mine ventilation air.