Page 107 - Advances In Productive, Safe, and Responsible Coal Mining

Mine ventilation networks optimized for safety and productivity 91

Intake (Not to scale)
Return
Neutral

Unmined coal

Face
R R
R
Tailgate Gob vent boreholes Seal Headgate

Seal
Gob

Fig. 6.3 Schematic longwall face ventilation detail for a progressively sealed panel.

(Not to scale)
Intake
Return
Neutral

Unmined coal
Face
R R R
R
Back return
Tailgate Nitrogen Headgate
injection
Gob vent boreholes
Seal
Seal
Gob

Fig. 6.4 Schematic longwall face ventilation detail for a progressively sealed panel with a back
return arrangement.

as the face advances. Seals on the tailgate side were built when the previous panel was
mined and the current tailgate served as the headgate. The fresh air, marked in blue,is
fed to the longwall face from the headgate side while the exhaust air, marked in red,
moves outby from the longwall face on the tailgate side.
Fig. 6.4 shows a variant of the U-type pattern referred to as a back return. By reg-
ulating the outby tailgate, part or all of the face air is directed inby and through the next
open crosscut. This moves the low pressure point inby from the tailgate and prevents