Where must automatic methane detectors be located according to the regulation?

• A. Intake airways at the interface between 2 NERZs and a NERZ/ERZ1
• B. Intersection between longwall face and intake airway
• C. Each main return airway
• D. All of the above, including each return airway in a vent split and 150m OB TG

Answer: (D)

Automatic methane detectors must provide early warning across the whole ventilation system by being placed at multiple critical points where methane can accumulate or migrate. The regulation requires detectors at intake airways where zones meet, specifically at interfaces between different NERZs and at the boundary of an NERZ with ERZ1. Placing a detector there catches methane as it moves from one zone to another, before it can be drawn into the main intake stream.

Detectors are also required at the intersection between the longwall face and the intake airway. This is a high-risk spot where methane can be liberated from the face and carried into the intake air, so monitoring there gives immediate notice of rising gas levels as mining activity continues.

In addition, detectors must be located in each main return airway. Monitoring the returns is essential because methane concentrating in the returning air can travel toward the surface; detecting it early in the return path helps prevent dangerous accumulations from reaching personnel or surface facilities.

All of the above, including each return airway in a vent split and 150 m OB TG, ensures full coverage of the ventilation network, including splits and outbye sections. This comprehensive placement minimizes blind spots, catches methane wherever it might accumulate or travel, and supports rapid response to any elevated readings.

In short, detectors must be placed at these key points to ensure timely detection throughout both intake and return paths, across zone interfaces, and in downstream sections of the ventilation system.