Under what condition does the requirement to monitor the auxiliary fan with a detector not apply?

• A. In drift or shaft driven from the surface in material other than coal
• B. In all underground sections without methane
• C. Only when the mine is not operating a booster fan
• D. When the detector is under maintenance and tagged out

Answer: (A)

The condition hinges on where methane gas can be present. The detector on the auxiliary fan is there to pick up methane and alert if it could accumulate as air is moved through the mine. If a drift or shaft is driven from the surface through material that is not coal, there isn’t coal seam gas generation in that leg, so the methane hazard is effectively absent. In that non-coal driving path, the requirement to monitor the auxiliary fan with a detector does not apply because the gas hazard the detector guards against isn’t expected there.

The other options describe situations where methane could still be a concern or where the rule isn’t tied to the geology of the drift: methane can be present in underground sections even if some parts are methane-free, the booster fan’s operation doesn’t determine whether the detector is needed, and a detector being under maintenance is a temporary administrative condition rather than the fundamental protection question.