What is the regulatory requirement for methane detectors on the main exhausting fan?

• A. The ventilating air passing through the main exhausting fan must be monitored by at least 1 automatic methane detector to detect the general body; the detector must automatically activate a visible alarm when the concentration exceeds the PHMP-specified limit.
• B. Detectors on the main exhaust are optional.
• C. At least two detectors are required but only audible alarms are needed.
• D. Detectors must monitor only carbon dioxide levels, not methane.

Answer: (B)

The main concept here is that methane detectors on the main exhausting fan are not mandated by regulation. In Queensland coal mining law, gas monitoring is driven by risk assessments and the mine’s Gas Management Plan. Detectors are placed where methane buildup is most likely or where monitoring provides meaningful protection—typically at faces, in return airways, or other points identified as high risk. The main exhaust itself is a dilution path, so having detectors there is not a blanket regulatory requirement. Therefore, the regulatory stance is that detectors on the main exhausting fan are optional, depending on the mine’s risk assessment and gas management strategy. If a mine decides to install them, it’s for internal safety management rather than because the regulations require it.