Fourteen miners have now been confirmed dead following an explosion at a coal mine in Sanjidi, near Quetta in Balochistan Province, Pakistan, on Sunday 12 August 2018. Nineteen miners were reportedly about 1200 m below the ground when the explosion occurred, and while rescue workers are still attempting to locate the five missing men, their attempts are being hampered by a build-up of piousness gas in the mine, and there is thought to be little chance of finding any survivors.
The approximate location of the Sanjidi coal mine. Google Maps.
Coal is formed when buried organic material, principally wood, in heated
and pressurised, 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.
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