An outburst is the sudden and violent ejection of coal, gas and rock from a coal face and surrounding strata in an underground coal mine. When outbursts occur, they can be very serious events, possibly even resulting in multiple fatalities.
Effects of outbursts
Outbursts may range in severity from being barely noticeable, to causing the destruction of an entire mining panel, and throwing pieces of machinery weighing tens of tonnes several metres. An outburst at Tahmoor Colliery, in NSW, Australia in June 1985 involved the ejection of 350 tonnes of coal and rock and over 3000 cubic metres of gas, resulting in one fatality. Another outburst at the nearby South Bulli Colliery in 1991 resulted in three fatalities, and yet another outburst at Westcliff Colliery in January 1994 involved 300 tonnes of coal and rock and resulted in one fatality.
Several factors predispose certain coal seams to being outburst-prone. These include:
Coal seam gas content (meas