How must a device behave when it detects a significant departure from the fan's normal operating parameters?

• A. Sends an email to maintenance; No action.
• B. Ignites a safety beacon.
• C. Triggers a visible alarm; Trips the electricity supply to the fan; Records the date and time of the action.
• D. Only logs the event.

Answer: (C)

When a device detects a significant deviation from how the fan is supposed to operate, the immediate priority is to warn people and stop the unsafe operation. The best response combines a visible alarm to alert workers, a trip of the fan’s power to halt its operation, and a record of when this action happened. This approach ensures that the hazard is mitigated right away and there is a precise, auditable log for investigations and compliance. Merely emailing maintenance, or only logging the event, would either delay action or fail to warn and stop the equipment, which is essential for safety in a mining ventilation system.