Protection against disturbance of air flow in coal-mine ventilation network using descending air streams

摘要

When sublevel excavations are ventilated, special attention should be paid to the development of a system of openings supplying air to the longwall faces.The presence of crosscuts and drifts connecting intake and return airways reduces the influence of ventilation on these excavations and as result diminishes the stability of the flow of air streams below development level.The article presents an example of the impact of a fire arising in a descending air stream on the distribution of air in the mine ventilation network.Development of fire in an excavation involves a risk of the reversal of airflow direction.When descending air streams are used, the layout of the ventilation network and the location of the fire in a given branch of the network are of considerable significance.Under some specific circumstances, a descending air stream can exert an indirect effect on the ventilation system after an underground fire occurred.Sublevel mining requires, at the design stage, guaranteeing stability of air streams with a power factor corresponding at least to strong air stream, equipping mining areas with emergency stoppings that allow for quick shutting down of a ventilation area upon a fire outbreak, and selection of a proper monitoring system