Eleven people have died following an explosion at a coal mine in Shaanxi Province, China, on Monday 21 August 2023. The incident took place at the Xintai Coal Mine close to the city of Yan'An, about 900 km to the southeast of Beijing, at 8.26 pm local time. Ninety people are reported to have been below ground at the time of the evacuation, most of whom were evacuated safely, although two later died of injuries sustained in the explosion, and nine miners who failed to escape from the mine were later found dead by rescue teams. Another eleven people are still being treated in hospital for injuries sustained in the explosion; all are reported to be in a stable condition.
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.
As coal is 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.
Despite attempts to modernise its energy network, China is still reliant on coal for much of its energy, with 400 000 tonnes of coal mined in China in July 2023, and over 200 million tonnes of coal imported each year, most of it from Indonesia, Australia, South Africa, the United States, and Russia. China has been trying to reduce its dependence on foreign coal by expanding its own coal industry with new mines such as Xintai, but this has come at the cost of more accidents within the industry.
An investigation into the cause of the explosion has now begun, with seven people reported to have been arrested, including the mine's owner and a major shareholder.
See also...
