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On at least two separate occasions, methane gas explosions occurred in underground mines when separate ventilation systems were connected. A review of these disasters indicated that conceptual errors made by the miners may have contributed to these fatal mistakes. The conceptual errors thought to be at fault concerned inadequate mental models of flow distribution changes within the mine ventilation circuit. Research conducted in this study indicates that connecting previously unconnected and unobstructed parallel circuits or adding one or more resistors results in inadequate mental models of flow distribution changes in over 70% of the 136 mine workers sampled.

t is well known that a major ventilation problem during deep cut mining is delivering the required amount of air into the immediate faoe zone. Line brattice face ventilation systems are commonly applied for medium and low coal seams in room and pillar mining method utilising continuous miner. It is assumed that the blowing curtain, as opposed to the exhaust curtain, generally achieves greater efficiency in delivering air to ventilate the immediate face zone. However, in real mining conditions both, the blowing and the exhaust curtain face ventilation systems suffer from one significant disadvantage -the intake air separates early from the rib and does not fully penetrates to the immediate face zone. This phenomenon is called flow separation. The portion of the intake air reaching the face can be <20% with the exact amount being a function of various parameters associated with the mine and ventilation design. The results presented in this publication clearly shows that curtain tight-rib distance, width of the entry, and curtain setback distance govern the flow behaviour at the face area. The performed analysis confirmed that changes in the intake air quantity have no significant impact on the flow patterns and the amount of air delivered to the immediate face zone.

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