Working equations are introduced to evaluate heat flow from the surrounding rocks and sensible heat ratio of a roadway, either partially or totally wet, using the concept of modified air temperature which was proposed in the 2nd report. The heterogeneous surrounding medium which consists of coal and sandstone or shale can be treated as an apparently homogeneous rock by introducing an equivalent thermal conductivity. Discussions are given on the temperature variation of ventilation air when the air temperature at the reference point changes with time. Equations are introduced by which air temperature can be calculated accurately enough in cases when the temperature at the starting point changes suddenly and sinusoidally.
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