What should be done immediately upon noticing a gas build-up in a mine?

Upon noticing a gas build-up in a mine, the immediate course of action is to evacuate the area and notify specialists. This is correct because gas accumulations pose a significant safety hazard, potentially leading to explosions, asphyxiation, or other dangerous conditions for those in the mine. Rapid evacuation minimizes the risk to personnel, ensuring that they are removed from a potentially life-threatening environment.

Notifying specialists then enables trained professionals to assess the situation and implement appropriate measures, such as gas detection and ventilation techniques, to safely address the gas build-up. This response is critical in ensuring the safety of all personnel and allowing experts to manage the risk effectively.

The other options do not prioritize safety, and engaging in them could result in dire consequences. Continuing operations as usual ignores the serious threat posed by gas build-up. Ignoring the signs until confirmed by testing could lead to insufficient response time, allowing the situation to worsen. Attempting to ventilate the area without delay could lead to unexpected hazards, such as igniting flammable gases, especially if the situation has not been properly assessed by professionals.