184
5 Main Ventilation
Advantages
• The haulage galleries are kept free of dust and gas, allowing workers to have a
cleaner working atmosphere.
• It simplifies the action of the rescue teams if fires or explosions occur. This is
because fresh air is in the access route, which makes it easier to instal equipment
and materials.
• The system can be more energy efficient. For this purpose, gradual expansion
outlets (evasés) should be used in the main fans which lower air discharge
velocities and improve static efficiency.
• In a mine with firedamp, as this gas has a lower density than air, this system
favours its evacuation to the exterior.
Disadvantages
• In winter, the temperatures can be very low in the mouth of the intake shaft making
it difficult to work in them, and may even lead to equipment malfunctions due to
freezing.
• It may be more difficult to detect a fire on the conveyor belt.
• Dust generated by transport in the downcast, as well as fires in these areas, can
reach the stopes.
• Dirty air and dust pass through the fan and may affect its normal functioning.
• Firedamp escapes from the already abandoned areas of the mine can be drawn
towards the centre of the mine with the subsequent problems.
5.5.2 Blower System
Blower ventilation causes air movement resulting in an overpressure in the area to be
ventilated. It has the following advantages and disadvantages (Tien 1978; Hartman
et al. 1997, p. 527):
Advantages
• While the fan is running, coal seams are under high pressure thus reducing the
gases emanating from them. Although this fact is debatable, at least in the case
of firedamp.
• The systems and areas through which air enters the mine are heated by the main
fan, thus preventing their freezing.
• Fire outbreaks are more obvious.
• The fan receives clean air, which extends its useful life.
• These types of fans are cheaper as they have a smaller diffuser.
Disadvantages
• It may hinder mine rescue efforts by tending to push contaminating gases into
escape routes.
5 Main Ventilation
Advantages
• The haulage galleries are kept free of dust and gas, allowing workers to have a
cleaner working atmosphere.
• It simplifies the action of the rescue teams if fires or explosions occur. This is
because fresh air is in the access route, which makes it easier to instal equipment
and materials.
• The system can be more energy efficient. For this purpose, gradual expansion
outlets (evasés) should be used in the main fans which lower air discharge
velocities and improve static efficiency.
• In a mine with firedamp, as this gas has a lower density than air, this system
favours its evacuation to the exterior.
Disadvantages
• In winter, the temperatures can be very low in the mouth of the intake shaft making
it difficult to work in them, and may even lead to equipment malfunctions due to
freezing.
• It may be more difficult to detect a fire on the conveyor belt.
• Dust generated by transport in the downcast, as well as fires in these areas, can
reach the stopes.
• Dirty air and dust pass through the fan and may affect its normal functioning.
• Firedamp escapes from the already abandoned areas of the mine can be drawn
towards the centre of the mine with the subsequent problems.
5.5.2 Blower System
Blower ventilation causes air movement resulting in an overpressure in the area to be
ventilated. It has the following advantages and disadvantages (Tien 1978; Hartman
et al. 1997, p. 527):
Advantages
• While the fan is running, coal seams are under high pressure thus reducing the
gases emanating from them. Although this fact is debatable, at least in the case
of firedamp.
• The systems and areas through which air enters the mine are heated by the main
fan, thus preventing their freezing.
• Fire outbreaks are more obvious.
• The fan receives clean air, which extends its useful life.
• These types of fans are cheaper as they have a smaller diffuser.
Disadvantages
• It may hinder mine rescue efforts by tending to push contaminating gases into
escape routes.