Explosions in coal mines are usually caused by which of the following gases?

Options :
  1. Hydrogen
  2. Carbon monoxide
  3. Air
  4. Methane
Answer and Explanation :-

Answer: Option 4


Methane (CH4) is a gas formed as part of the process of coal formation - coalification. When coal is mined methane is released from the coal seam and the surrounding disturbed rock strata. Methane can also be released as a result of natural erosion or faulting. Methane is released during the process of extracting coal in both surface and underground mining. The released methane then mixes with air, which becomes highly explosive if methane concentration levels reach 5-15%. Methane explosions are devastating, causing significant loss of life and damage to property. There is significant industry effort to prevent these accidents occurring. The risk of explosion is a particular problem in underground mines, where providing a sufficient level of ventilation air is essential. Failure to provide enough air to dilute the methane below the 5-15% range can put miners at risk due to the threat of explosion. In surface mining, the released methane is heavily diluted by its immediate exposure to air and therefore the risk of explosion is minimal. Methane explosions in underground mines cause a large number of deaths around the world each year. While these numbers are still too high, they have been falling year on year in recent times as awareness of the hazards of methane has increased and methane recovery technologies have been improved and deployed on a wider scale.

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