Mine Ventilation topic related to auxiliary ventilation. Only one type of auxiliary ventilation is discussed i.e., auxiliary fans and vent pipe because this method is more efficient as compared to other methods but method selection depends upon your problem and requirement means which method best suited to your needs.

1. Haroon Khan
Mine Ventilation
Mining Engineering

2. Contents
 Auxiliary ventilation
 Auxiliary ventilation methods
 Auxiliary Fan and Vent Pipe
 Types
 Design parameter
 Vent pipe
 Fan
 Advantages
 Disadvantages

3. Auxiliary Ventilation
 Important component of overall ventilation
 Without adequate auxiliary ventilation, it is impossible to provide sufficient air to
working faces
 Auxiliary ventilation used to ventilate:
 Development sections
 Dead-end headings
 Active mine faces
 End of drifts
 Crosscut
 Raises
 Entries

4. Auxiliary Ventilation Methods
 Three methods of auxiliary ventilation system
1. Line brattices
2. Auxiliary fan and vent duct/pipes
3. Ductless air movers (compressed air)
Air flow inside a heading using a Auxiliary fan and vent pipe

5. 2. Auxiliary Fan & Vent Pipe System
 Auxiliary Fan
 Fans are primary means of producing and controlling the airflow
 It draws air from main ventilating current
 Force it through metal pipe to specific places for ventilation
 Vent Pipe
 Pipe in which air is pumped to ventilate the specified places
 Fans are connected to pipes
 Pipes are suspended from top or walls using timber set or hangers
 Most economical and desirable method

6. Types
1. Blowing
 High velocity air stream emerging from pipe near face
 Cause turbulent mixing of methane & prevent methane layer
formation at roofs level
 Create cooling effect near face
2. Exhausting
 When dust is main concern
 Dust collector are used with it
 Selection depends upon pollutants of greatest concern, dust,
gases or heat

8. Design Parameters
 Vent Pipe
1. Types
Rigid
 Used material steel alloys, braided steel mesh, fiberglass and resin
 Exhaust pipe are always rigid and recoverable
Flexible
 Nylon made
 Blowing ducts are flexible
2. Diameters
3. Length
Increase in pipe length decrease leakage in pipe b/c of reduction in
no. of joints

9. Vent pipe cont…
4. X-section
Circular
Elliptical
5. Shock losses
Due to bends, junctions and sudden change in x-sectional area
6. Friction losses
Due to roughness and geometry of pipe
7. Installation
At middle in semicircular shape
At corners in rectangular shape

10. Design Parameters
 Fan
1. Numbers and spacing
 If length is greater then number of fan used and its spacing determination
2. Types
 Axial fan
 High flow-rate and low-pressure fan
 Mostly used in hard rock mines
 Centrifugal fan
 High pressure and low flow-rate fan
 Mostly used in coal mines
 Axial fans are preferable because they are simple, lighter, cheaper and compact
size

11. Fan cont…
3. Upgradation of fan to make working conditions safer.
4. Fan pressure
 Must be adequate to compensate the pipe friction and losses
 Important factor to be considered in design & selection of fan is to
ensure that there is no air recirculation

12. Advantages
 Provide more positive and controlled ventilating effect at face
 Cause no additional resistance to mine ventilation
 Cause no leakage to main mine ventilation system
 Exhausting duct advantage for dust control

13. Disadvantages
 High initial capital cost
 Need of electrical power for Auxiliary Fans
 Space required for the Ducts/Pipes
 Noise of the Auxiliary Fans