Four miners have been killed and another two injured in an accident at a coal mine in the Jhelum District of Punjab Province, Pakistan on Saturday 31 March 2018. The incident, which happened late in the evening, at an Ali Mines operated site, is reported to have occurred when an explosion in the mine triggered a roof collapse.
The approximate location of the 31 March 2018 Punjab mine accident. 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.
Follow Sciency Thoughts on Facebook.