A.0.15m/s B.0.25m/s C.0.35m/s D.0.45m/s
A.低瓦斯礦井 B.高瓦斯礦井 C.煤與瓦斯突出礦井 D.瓦斯礦井
A.3m/s B.4m/s C.8m/s D.10m/s