Felipe Calizaya

Michael G. Nelson

Jessica Wempen

Randy Peterson

2011

UTILIZATION OF BOOSTER FANS IN UNDERGROUND COAL MINES

University of Utah, Salt Lake City, UT

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 Colliery3

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 Ventilation4

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 Ventilation5

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

b) Long -section View

a) Inlet Side SS

FF

a) Cross-section View

Inlet Outlet

Daw Mill Colliery Ventilation6

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 Ventilation7

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 Ventilation8

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 Colliery9

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

DEPTH IN METRES.

BARNSLEY SEAM

SWALLOW WOOD SEAM

HAIGH MOOR SEAM

PARKGATE SEAM

THORNCLIFFE SEAM

812m

822m

960m

982m

No.1 SHAFT No.2 SHAFT No.3 SHAFT.1911-1972SEAM EXHAUSTEDAFTER 61 YEARS

WORK BEGAN 1970SEAM ABANDONED

1993.

SEAM PARTIALLYWORKED LATER

ABANDONED.

CURRENTWORKINGS

Maltby Colliery

Maltby Colliery Ventilation12

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 Ventilation13

One 2.05 m axial booster fan operating at 140 m3/s with a pressure of 7.4 kPa

Section View

Airflow

Screen

Diffuser

Bulkhead

Drift Floor

Impeller

Motor

Maltby Colliery Ventilation14

Maltby Colliery Ventilation

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

15

Maltby Colliery Ventilation16

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 Ventilation17

Booster fan installation includesfour 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 Ventilation18

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

Intake

Return

Man Doors

Booster Fan

Airlock Doors

Bulkhead

To Tail Gate

Tube Bundle

MethaneCarbon Monoxide

Manometer

Smoke

Delta Press

Fan and Environmental Monitors

Kellingley Colliery20

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

Diffuser

BulkheadCasing

InletDischarge

Centrifugal Booster Fan

25

Kellingley Colliery Ventilation

Intake

Return

Bulkhead

Airlock Doors

Booster Fan

Airlock Doors

Methane Carbon Monoxide

TemperatureDelta Press

Fan and Environmental Monitors

26

2 x 2 Booster Fans

Return

BulkheadAirlock Doors

Intake

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 US28

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 US29

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 US30

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

31

Booster fan model for Highland 9 Mine

North

East Mains

North Mains

West Mains

Unit 1: 9.4 cms

Legend

Main Fan

Unit 4: 9.4 cms

Unit 2: 9.4 cms

Unit 5: 9.4 cms

Unit 3: 9.4 cms

Mined Out Area

Mined Out Area

Highland Mine projected ventilation network using only a main fan

Summary of Results:  Main fan duty: 200 m3/s at 2.24 kPa Total airpower: 440 kW

North

East Mains

North Mains

West Mains

Unit 1: 9.4 cms

Legend

Main Fan

Unit 4: 9.4 cms

Unit 2: 9.4 cms

Unit 5: 9.4 cms

Unit 3: 9.4 cms

Booster Fan

Mined Out Area

Mined Out Area

Highland Mine projected ventilation network using one booster fan

Summary of Results:  Main fan duty: 180 m3/s at 1.37 kPa Booster fan duty: 150 m3/s at

0.57 kPaTotal airpower: 330 kW

North

East Mains

North Mains

West Mains

Unit 1: 9.4 cms

Legend

Main Fan

Unit 4: 9.4 cms

Unit 2: 9.4 cms

Unit 5: 9.4 cms

Unit 3: 9.4 cms

Booster Fan 1

Mined Out Area

Mined Out Area

Booster Fan 2

Highland Mine projected ventilation network using two booster fans

Summary of results: Main fan duty: 150 m3/s at 1 kPa Booster fan 1 95 m3/s at duty 0.5 kPaBooster fan 2 : 65 m3/s at duty 0.5 kPaTotal airpower: 230 kW