5.3 Natural Ventilation
181
R =
P v 2 + P n
Q
2
2
=
3500 Pa + P n
700
m 3
min
2
Equating:
8000 Pa + P n
1000
m 3
min
2 =
3500 Pa + P n
700
m 3
min
2
Finally:
P n = 823.53 Pa
5.4 Forced Ventilation
When air is supplied to a certain space using mechanical devices called fans, a forced
ventilation system is being used. Depending on the location of the ventilation shaft
with regard to the ore deposit, two types of forced ventilation are distinguished:
central and boundary.
5.4.1 Central Ventilation
In this ventilation system, also referred to as bidirectional, downcast and upcast shafts
are very close together and located in the centre of the mineral deposit (Fig. 5.6). It
is characterized by the movement of air from the centre of the mine to the stopes,
and to return through the ventilation galleries to the upcast, which, as has been
already indicated, is located in the centre of the mineral deposit. In this case, the
upcast shaft can be used for the extraction in parallel with the downcast shaft. It is
a common ventilation system in medium-sized mines. Some of the main advantages
and disadvantages of this system are set out below (Novitzky 1962, p. 254).
Advantages
• Grouped installations, and
• It is more convenient in the early stages of the mine.
Disadvantages
• This system increases the resistance of the circuit a lot, which is more evident as
the mine increases.
181
R =
P v 2 + P n
Q
2
2
=
3500 Pa + P n
700
m 3
min
2
Equating:
8000 Pa + P n
1000
m 3
min
2 =
3500 Pa + P n
700
m 3
min
2
Finally:
P n = 823.53 Pa
5.4 Forced Ventilation
When air is supplied to a certain space using mechanical devices called fans, a forced
ventilation system is being used. Depending on the location of the ventilation shaft
with regard to the ore deposit, two types of forced ventilation are distinguished:
central and boundary.
5.4.1 Central Ventilation
In this ventilation system, also referred to as bidirectional, downcast and upcast shafts
are very close together and located in the centre of the mineral deposit (Fig. 5.6). It
is characterized by the movement of air from the centre of the mine to the stopes,
and to return through the ventilation galleries to the upcast, which, as has been
already indicated, is located in the centre of the mineral deposit. In this case, the
upcast shaft can be used for the extraction in parallel with the downcast shaft. It is
a common ventilation system in medium-sized mines. Some of the main advantages
and disadvantages of this system are set out below (Novitzky 1962, p. 254).
Advantages
• Grouped installations, and
• It is more convenient in the early stages of the mine.
Disadvantages
• This system increases the resistance of the circuit a lot, which is more evident as
the mine increases.