What action must be taken if a reading of > 0.5% methane is detected in the general body where welding is being carried out in a permanent underground workshop?

• A. Continuing work with added PPE.
• B. Stopping work and quench hot material.
• C. Evacuate the area only after ventilation check.
• D. Postpone until a supervisor approves.

Answer: (B)

Methane is a highly ignition-prone gas in underground coal mining, and welding creates sparks and heat that can ignite methane in the surrounding air. When the methane reading in the general body of air exceeds a safe threshold, the immediate priority is to remove ignition sources. Stopping the welding stops the production of sparks, while quenching hot material removes the hot ignition source that could ignite methane if it contacts the gas-saturated air. PPE cannot neutralize the gas or eliminate the ignition risk, and waiting for ventilation checks or supervisor approval would leave the area exposed to a potential ignition. After stopping, the area should be ventilated and gas levels reassessed before resuming work.