What percentage of methane is known to cause explosions in a mine?

Methane is a significant concern in mining operations due to its potential to create explosive atmospheres. The flammability limits for methane, which define the range of concentrations that can ignite and cause an explosion, typically start at around 5% and go up to approximately 15% in the air. Thus, when the concentration of methane in the environment falls within this range, it can mix with air to create a potentially explosive mixture.

This concentration range signifies that the proper management of methane levels is critical in mine safety protocols. Understanding this percentage helps in assessing the risk and implementing proper ventilation and monitoring systems in underground mines to prevent dangerous conditions that could lead to explosions. In this context, the range of 5-15% accurately reflects the concentrations of methane that can lead to explosions, justifying the choice as the correct answer.