UTILIZATION OF BOOSTER FANS
IN UNDERGROUND COAL MINES
Felipe Calizaya
Michael G. Nelson
Jessica Wempen
Randy Peterson
University of Utah, Salt Lake City, UT
2011
INTRODUCTION
Booster Fan:
1) An underground fan installed in the main air stream
to handle the quantity of air circulated through a
section
2) Installed in a permanent bulkhead and equipped
with a set of airlock doors and fan monitors
3) A properly sized and sited booster fan can be used
to create safer work conditions and allow the
extraction of minerals from great depths
Daw Mill Colliery
3





Daw Mill Colliery is the most significant coal mine in the UK
producing 3 million tonnes per year
The mine is deep and extensive with a depth over 850 m and over
7.5 km of workings
A retreating longwall is used as the primary means of production
Longwall panels are developed with a single entry. Panels are
2,500 m long and 350 m wide
Isolation pillars from 90 to 180 m wide are left between each panel
Daw Mill Colliery Ventilation
4





One intake shaft and one exhaust shaft
A surface drift used to transport coal provides 20 m3/s of intake
air
Two exhausting centrifugal surface fans are installed on the
surface. One fan is active and one fan is redundant
Both surface fans are capable of operating at 169 m3/s with a
pressure of 2.8 kPa
Production headings are ventilated with at least 6.5 m3/s, this is
driven by a 90 kW auxiliary fan operating at 3.5 kPa
Daw Mill Colliery Ventilation
5
One booster fan site that consists of four 2 m axial
booster fans with a combined capacity of 120 m3/s
with a pressure of 3.5 kPa
Outlet
Inlet
a) Inlet Side
F
S
a) Cross-section View
F
S

b) Long -section View
Daw Mill Colliery Ventilation
6




Booster fans are located in the return and the motors are
enclosed in flame proof housing
Because of the risk of spontaneous combustion booster fans
were installed in rock above the coal seam
Booster fans are sited inby the current neutral ventilation
point so there is a small amount of air recirculation (less than
10%)
Booster fans are essential to provide adequate air volume
and control heat. The fans increase the volume of air at the
longwall face by 50%
Daw Mill Colliery Ventilation
7

Ventilation challenges include:


Methane – 2 m3 of methane per ton of coal
Spontaneous combustion – can occur regularly during
development and salvage operations
Daw Mill Colliery Ventilation
8




Methane and carbon monoxide levels are measured throughout
the mine
At the booster fans airflow, pressure, vibration, bearing
temperature, methane, and carbon monoxide are constantly
monitored
In addition to electronic monitoring, a tube bundle system is used
to monitor air quality
Because of the high risk of spontaneous combustion a nitrogen
system is used
Maltby Colliery
9




Maltby Colliery produces 3 million tons per year ROM
and 1 million tons per year clean coal
A retreating longwall is used as the primary means of
production and is supported by four development sections
Longwall panels are developed with a single entry system
The mine is deep and extensive with a depth over 960 m
and over 8 km of workings
Maltby Colliery
1911-1972
SEAM EXHAUSTED
AFTER 61 YEARS
No.1 SHAFT
No.2 SHAFT
No.3 SHAFT.
DEPTH IN
METRES.
BARNSLEY SEAM
WORK BEGAN 1970
SEAM ABANDONED
1993.
812m
SWALLOW WOOD SEAM
822m
HAIGH MOOR SEAM
SEAM PARTIALLY
WORKED LATER
ABANDONED.
CURRENT
WORKINGS
960m
PARKGATE SEAM
THORNCLIFFE SEAM
982m
Maltby Colliery Ventilation
12



Two intake shafts and one exhaust shaft
Two 5.3 m centrifugal exhaust fans are installed on the
surface. One fan is active and one fan is redundant
Both fans are capable of operating at 280m3/s with a
pressure of 5.5 kPa.
Maltby Colliery Ventilation
13

One 2.05 m axial booster fan operating at 140 m3/s
with a pressure of 7.4 kPa
Bulkhead
Screen
Impeller
Airflow
Motor
Diffuser
Section View
Drift Floor
Maltby Colliery Ventilation
14
Maltby Colliery Ventilation
15

Ventilation challenges include:
 Heat
– Virgin rock temperature is near 42⁰C and air
picks up an additional 7 ⁰C across the booster fan
 Humidity
– High water usage for dust control and
machine cooling
 Methane
– 25 m3 of methane produced per ton of coal
 Frictional
Ignition
Maltby Colliery Ventilation
16




Booster fan is located in the return and the motor is enclosed
in flame proof housing
Booster fans are essential to provide adequate air volume
and control heat
Booster fan is sited inby the current neutral ventilation point
so there is some air recirculation
Methane drainage system is used to control excess methane
Maltby Colliery Ventilation
17



Booster fan installation includes
four airlock doors between the
intake and the return. Three
airlock doors are used in the
fan bulk head
A manometer and a digital
pressure gauge are used to
measure pressure across the
bulk head
The installation includes a water barrier to control fire that
may occur at the fan
Maltby Colliery Ventilation
18



Methane is monitored in the intake and in the return
upstream and downstream from the fan
Carbon monoxide and smoke detectors are located
downstream
A tube bundle system is also used to monitor the air
quality
Maltby Colliery Ventilation
To Tail
Gate
Bulkhead
Man Doors
Return
Booster Fan
Airlock Doors
Intake
Fan and Environmental Monitors
Tube Bundle
Methane
Carbon Monoxide
Manometer
Smoke
Delta Press
Kellingley Colliery
20




Kellingley Colliery produces 2.3 million tons per year
A retreating longwall is used as the primary means of
production and is supported by four development sections
Longwall panels are developed with a single entry system
The mine is deep and extensive with a depth over 800 m
and over 9 km of workings
Kellingley Colliery Ventilation
21



One intake shaft and one exhaust shaft
Two 4.14 m centrifugal blowing fans are installed on
the surface. One fan is active and one fan is redundant
Both fans are capable of operating at 290 m3/s with
a pressure of 2.5 kPa.
Kellingley Colliery Ventilation
22

Three booster fan sites all located in the return


Single 1.6 m double inlet centrifugal fan operating at 290
m3/s and7 kPa
Four 1.2 m axial fans operating at 68 m3/s and 2.5 kPa,
two installations one in the return and one in intake
Kellingley Colliery Ventilation
23
Bulkhead
Diffuser
Discharge
Casing
Inlet
Centrifugal Booster Fan
Kellingley Colliery Ventilation
Intake
Bulkhead
Booster Fan
Return
Airlock
Doors
Airlock Doors
Fan and Environmental Monitors
25
Methane
Delta Press
Carbon Monoxide
Temperature
2 x 2 Booster Fans
Intake
Airlock Doors
Bulkhead
Return
26
Kellingley Colliery Ventilation
27

Ventilation challenges include:




Methane, Heat, and Dust
Booster fans are essential to provide adequate air volume
and control heat
There is a small amount of air recirculation (less than 10%)
Turbulence around the multi-fan installation can be a
problem
Significant Differences in Ventilation
Practices Between the UK and the US
28




Booster fan installations are common and are accepted as a
safe and effective means of ventilating sections
Booster fans are often viewed as the only option for
providing adequate ventilation underground
Booster fans are most commonly axial fans installed in
clusters with up to four-two stage fans per site and all fans
were installed in concrete bulk heads
Booster fans were selected based on each mines pressure
and quantity requirements
Significant Differences in Ventilation
Practices Between the UK and the US
29





Two types of parameters were monitored at each fan: fan parameters and
environmental parameters
Fan parameters included differential pressure, motor and bearing
temperatures, and air velocity
Environmental parameters included methane, carbon monoxide, and smoke.
Atmospheric monitoring systems were extensive and robust
Booster fans were most often located in the returns in series with the main
fans
Motors and electrical components were located in the return but were
contained in flame proof housing
Significant Differences in Ventilation
Practices Between the UK and the US
30




There was no electrical interlocking between the main fans and the
booster fans at any of the mines
All of the coal mines were using single entry systems with barrier
pillars between the longwall panels
No neutral entry for the conveyor belts were used. Belts were used
in both intake and in return airways
Recirculation and series ventilation are not strictly prohibited. Most
mines using booster fans were recirculation about 10% of the air
Booster fan model for
Highland 9 Mine
31
Unit 3: 9.4 cms
Unit 5: 9.4 cms
North Mains
Highland Mine
projected ventilation
network using only a
main fan
Summary of Results:
West Mains
Unit 1: 9.4 cms
Main fan duty:
Total airpower:
East Mains
Unit 2: 9.4 cms
Legend
Main Fan
North
Unit 4: 9.4 cms
200 m3/s at
2.24 kPa
440 kW
Highland Mine
projected ventilation
network using one
booster fan
Unit 3: 9.4 cms
Unit 5: 9.4 cms
North Mains
West Mains
Summary of Results:
180 m3/s
at 1.37 kPa
Booster fan duty: 150 m3/s at
0.57 kPa
Total airpower:
330 kW
Main fan duty:
Unit 1: 9.4 cms
East Mains
Unit 2: 9.4 cms
Legend
Main Fan
North
Booster Fan
Unit 4: 9.4 cms
Highland Mine
projected ventilation
network using two
booster fans
Unit 3: 9.4 cms
Unit 5: 9.4 cms
North Mains
West Mains
Unit 1: 9.4 cms
East Mains
Summary of results:
Main fan duty: 150 m3/s at
1 kPa
Booster fan 1 95 m3/s at
duty
0.5 kPa
Booster fan 2 : 65 m3/s at
duty
0.5 kPa
Total airpower: 230 kW
Unit 2: 9.4 cms
Legend
Main Fan
North
Booster Fan 1
Booster Fan 2
Unit 4: 9.4 cms