What is the Longwall ventilation requirement?

• A. 4 m3/s per m of extraction height
• B. 2 m3/s per m
• C. 6 m3/s per m
• D. 8 m3/s per m

Answer: (A)

Longwall ventilation is sized to provide enough air to dilute methane and carry away dust along the face and gob. The amount of air needed grows with the height of the coal seam being mined, because more contaminants are produced as extraction height increases. To capture this, the guideline uses a fixed air flow rate for each metre of extraction height, so the total required airflow is that per-metre rate multiplied by the seam height. This approach keeps gas concentrations within safe limits and ensures effective contaminant control as the longwall advances. If the seam height changes, the required flow changes proportionally, which is why the per-metre rate is the key concept.