Eleven miners and two rescue workers have been killed in two separate incidents at coal mines in Balochistan Province, Pakistan, within the last week. On Thursday 11 March 2021, eight miners working 300 m below ground at a mine in the town of Marwār, close to the border with Afghanistan, were buried following a methane explosion. Two of these miners were later dug out alive, but the remaining six died. On Monday 15 March five miners entered a mine near Tor Ghar in Harnai District, to carry out repair work following a fire, also thought to have been caused by a methane build-up. All five miners were overcome by fumes within the mine and died, as did two rescue workers who entered the mine after them.
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.
Fire is much feared in coal mines due to this combination of flammable gas and solids, with methane and coal dust both potentially explosive when they come into contact with naked flames. To make matters worse, the limited oxygen supply in mines often means that such fires will involve incomplete combustion, in which all the oxygen is used up, but instead of forming carbon dioxide forms the much more deadly carbon dioxide, with potentially lethal consequences for anyone in the mine.
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 monoxide, 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 coal industry in Balochistan is notoriously dangerous, with extensive deposits of coal, much of which is rich in methane, and a large coal industry, where safety standards are generally very low, with miners having little access to specialist training or equipment. Four miners were killed in a methane explosion in Harnai District in February 2021, and the Balochistan Coal Mines Workers Federation has recorded 102 fatalities in mines in the province in the past year. The situation is made more complicated by an insurgency being waged
by Balochistan nationalists, who wish to unite Balochistan Province
with Sistan and Baluchestan Province in Iran and the Balochistan region
of southern Afghanistan into a new, independent, state, and who
sometimes carry out attacks on projects such as mines, which they see as
exploiting the region's wealth for the benefit of outside interests.
See also...
Follow Sciency Thoughts on Facebook.
Follow Sciency Thoughts on Twitter.