Twenty one miners have been confirmed dead and a further 69 have been injured, 50 of whom requiring hospital treatment, following an explosion at the Zemestanyurt coal mine, close to the town of Azadshahr in Golestan Province, Iran, at about 12.45 pm local time on Wednesday 3 May 2017. Rescue efforts are ongoing, with local authorities and the Iranian Red Crescent reporting uncertainty as to the number of people still trapped underground.
People waiting for news outside the Zemestanyurt coal mine in Golestan Province on 3 May 2017. Tasnim/Reuters.
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.
