Page 64 - Advanced Mine Ventilation

Estimation of Ventilation Air Quantity 47

desirable ventilation quantities for different categories of coal seams of the northern
and southern Appalachian Basin, United States. With proper ventilation planning, it
appears possible to deliver these quantities of air to the longwall face and bleeders.
It is also assumed that 50% of the original gas content has been drained before mining.
It should also be noted that for 15,000- to 20,000-foot long panels, it is imperative
to provide an internal return as shown in Fig. 4.3e4.5. Longwall ventilation must be

Figure 4.3 Ventilation layout for a longwall panel in mildly gassy coal seams.

Figure 4.4 Ventilation layout for a longwall panel in moderately gassy coal seams.