Overview of Gas Outbursts and Unusual Emissions

Gas and rock outbursts are unwanted complications of underground coal mining, which have occurred over the last 150 years of underground coal mining worldwide and are still occurring. ‘Outburst’ is a dynamic phenomenon that causes the sudden concurrent release of gas and strata energy. The released energy causes pulverization of large amounts of coal and rocks, which are then ejected into the working areas during mining of the outburst prone zone. This paper discusses some of the 30,000 outburst events recorded worldwide and suggests indices to identify the outburst zones as well as methods of management of outbursts. The conclusions are based on overseas and Australian experiences particularly research carried out by the authors in the early 1990s in coalfields of the Illawarra area.