Four workers are described as being in critical conditions and a fifth is described as being seriously injured following an explosion at a coal mine in Queensland on Wednesday 6 May 2020. The men were working at the longwall face (site of excavation) of the Anglo-American operated Grosvenor Coal Mine at Moranbah in the Isaac Region of central Queensland at the time of the incident, and were subsequently airlifted to a specialist burns unit at the Royal Brisbane Hospital. All operations at the mine have been halted pending an investigation by the Queensland Government.
Injured mineworkers from Moranbah being evacuated to Brisbane for specialist medical attention. ABC News.
Coal is formed when buried organic material, principally wood, in heated and pressurized, forcing off hydrogen and oxygen (i.e. water) and leaving more-or-less pure carbon. Methane is formed by the decay of organic material within the coal. There is typically little pore-space within coal, but the methane can be trapped in a liquid form under pressure. Some countries have started to extract this gas as a fuel in its own right. When this pressure is released suddenly, as by mining activity, then the methane turns back to a gas, expanding rapidly causing, an explosion. This is a bit like the pressure being released on a carbonated drink; the term 'explosion' does not necessarily imply fire in this context, although as methane is flammable this is quite likely.
Coal is also comprised more or less of pure carbon, and therefore reacts
freely with oxygen (particularly when in dust form), to create carbon
dioxide and (more-deadly) carbon dioxide, while at the same time
depleting the supply of oxygen. This means that subterranean coal mines
need good ventilation systems, and that fatalities can occur if these
break down.
The Grosvenor Coal Mine is well known to have a problem with mine gas, with the coal deposits there often described as 'gassy', which had led to several previous incidents at the mine, as well as repeated concerns about workers safety being raised by the Construction, Forestry, Maritime, Mining and Energy Union. The union has also raised concerns about the number of workers being hired via agencies, on short term contracts with reduced rights, which can make workers feel unable to speak up about health and safety issues.
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