What must be fitted to each surface fan and booster fan to detect a significant departure from the fan's normal operating parameters?

• A. A dust sensor.
• B. A basic on/off switch.
• C. An equipment condition monitoring device capable of continuously monitoring and recording the fan's static pressure.
• D. A battery backup only.

Answer: (C)

The key idea is continuous performance monitoring through an equipment condition monitoring device that records static pressure. Static pressure directly reflects the resistance the ventilation system faces and the fan’s ability to push air through the mine. By continuously monitoring and recording this parameter, you can spot significant departures from normal operating conditions—such as increasing resistance from duct blockages, impeller wear, or damper faults—and trigger timely maintenance before airflow or safety is compromised.

Other options don’t provide this ongoing diagnostic capability: a dust sensor tracks particulate matter, not how the fan is performing; a basic on/off switch only indicates presence or absence of operation and doesn’t reveal trending changes; a battery backup ensures power continuity but doesn’t monitor or record fan performance.