5.8 Ventilation and Exploitation Method
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Transport level
Sinking level
Production level
Air injection level
Air extraction level
Block system
Fig. 5.13 Air circulation in the block caving method
Intact coal
Goaf
CH 4 purge
Fig. 5.14 U-shaped ventilation for longwall mining with two entry routes
In addition, there is usually a purge system with its own fan which separates CH 4
from the previous circuit. A particularly up-to-date review of ventilation techniques
in coal mining can be found in Gillies and Wu (2013).
From the point of view of ventilation, coal mines can be divided into sections or
ventilating districts. These are independent ventilation units into which the mine is
divided to avoid enrichment in noxious gases and dust, but above all, in firedamp.
Their main function is to prevent ventilation air enrichment in the above-mentioned
gases as a consequence of it crossing the stopes successively. Districts are considered
as being independent when they have only the main inlet and outlet airways in
common (e.g. MIE 1985). By main airways, we refer to those galleries or shafts in
which circulating air has not already passed through an active stope (Fig. 5.15).