What defines a Hazardous Zone in this context?

• A. Methane in GB is > 1.25%
• B. Oxygen less than 19.5%
• C. Methane between 0.5% and 1%
• D. Methane > 1.25%

Answer: (D)

Hazardous Zones are areas where the atmosphere presents an explosion risk because of flammable gas in the air. In this mining context, methane is the main concern, so the zone is defined by how much methane is present. When methane exceeds 1.25% by volume, the environment is considered hazardous because the gas-air mix can ignite under typical ignition sources, triggering stricter controls, gas monitoring, ventilation, and equipment requirements. Oxygen level being below 19.5% is a serious safety issue for breathing, but it’s not the trigger used here to classify a Hazardous Zone. Similarly, methane concentrations below the threshold don’t meet the criterion for that classification.