On underground points, which location must air flow rate be recorded at least once on each working shift?

• A. The goaf area
• B. The surface intake
• C. The mine's working faces
• D. The main upcast fan

Answer: (C)

Recording the air flow rate at the mine’s working faces is essential because that is where miners are exposed to the ventilation air and where conditions can change most quickly as mining progresses. The face is the critical point of the system: dust, gases, heat, and airflow demands shift as equipment and rock move, so measuring there at least once per shift provides a true picture of the air actually reaching workers. If airflow at the face drops, conditions can become unsafe long before upstream measurements would indicate a problem, prompting prompt corrective action (adjusting ventilation, changing airway settings, etc.). Other locations like a goaf area, surface intake, or the main upcast fan reflect different parts of the system and may not reveal the real-time conditions at the face, so the per-shift requirement focuses on the working faces to ensure immediate safety.