Table 1 Geometric dimensions of the studied region and parameters of the air stream flowing through them Case 1 Case 2 Case 3 Case 4 The width of longwall 4.2 m 3.6 4.2 4.2 m galleries The height of longwall 3.2 m 3.0 m 3.2 m 3.2 m galleries Lowering of the longwall floor in relation 0.5 m to the tailgate floor The length of the unliquidated part of the airway behind the caving 4.0 m 4.0 m 2.0 m 4.0 m line of the longwall (a) The location of the outlet from the air duct in relation to the liquidation 8.0 m 8.0 m 6.0 m 8.0 m line of the airway (c) The location of the end of the ventilation brattice
in relation to the liquidation 2.0 m line of the airway (b)
Our group walked along, listening, as the guide explained the underground work and the use of brattice
partitions to assist air ventilation.
It snapped in the middle, and, pitching direct down the shaft, smashed the brattice
in its ponderous fall, pulling down after it the wooden lining of the shaft, bringing away masses of masonry, and, as it is supposed, stopping midway in its flight, and acting as a platform on which to pile an immense heap of broken timber, stone and rubbish.
There is also a 9 m by 11 m elliptical shaft, some 156 m deep, equipped with a precast concrete brattice
wall to provide upcast ventilation in the one portion of the shaft and a 12 t capacity conveyance located on rope guides in the other.
Fire-retardant materials have also been developed for other applications in mines such as ventilation ducting, brattice
cloth (sheets used for ventilation control) and cables.