Mixture of which one of the following pairs of gases is the cause of occurrence of most of the explosions in mines?

1. Explosions in coal mines are a major hazard. 2. These are most often caused by the ignition of flammable gas mixtures present in the mine atmosphere. 3. The primary flammable gas released from coal seams is Methane (CH4), often called firedamp. 4. When methane mixes with air (which contains oxygen) within certain concentration limits (typically 5-15%), it forms an explosive mixture that can be ignited by sparks, flames, or heat. 5. Therefore, the mixture of Methane and air is the cause of occurrence of most explosions in mines.