If a machine has 2 fixed methane detectors and only 1 fails, does the machine need to automatically shutdown?

• A. Yes, automatically shutdown
• B. No, Not if one detector remains operational
• C. Only if the other detector is above threshold
• D. It depends on the mine section

Answer: (B)

Redundancy in safety systems means one working detector is enough to keep monitoring the area. With two fixed methane detectors, the design expects the machine to keep running even if one detector fails, as long as the other detector is still functioning and giving valid readings. So automatic shutdown isn’t required just because one detector has failed; the remaining detector will continue to warn if methane levels rise, and maintenance can repair the failed unit without stopping the machine on that fault alone. The alarms and fault indications would alert crews to service the failed detector, while an actual shutdown would typically happen only if methane concentrations exceed the safe limits or if both detectors are out of service.