Which gas is commonly monitored for safety in mining environments?

Methane is commonly monitored in mining environments primarily due to its potential hazards. It is a colorless, odorless gas that can accumulate in underground mines, particularly in coal mines. The presence of methane poses significant risks, such as the potential for explosions if it reaches certain concentrations in the air. Monitoring methane levels is crucial to ensure safe working conditions for miners, as high levels can indicate a dangerous situation that might necessitate immediate action, such as evacuation or ventilation adjustments.

The other gases listed do not pose the same level of immediate risk in typical mining operations. Carbon dioxide can accumulate in enclosed areas but is usually not the primary focus when it comes to monitoring in mines. Nitrogen is inert and generally does not pose a danger in the context of mining environments. Helium is rarely encountered in mining operations and does not present the same safety concerns as methane does. Therefore, the emphasis on monitoring methane directly addresses the critical need for safety and risk management in mining operations.