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: An underground fan installed in the main air stream to handle the quantity of air circulated through a section Installed in a permanent bulkhead and equipped with a set of airlock doors and fan monitors 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 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 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 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 Inlet Outlet a) Inlet Side S F a) Cross-section View b) Long -section View

Daw Mill Colliery Ventilation 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 Ventilation challenges include: Methane – 2 m3 of methane per ton of coal Spontaneous combustion – can occur regularly during development and salvage operations Changed hyphens to en dashes, with a space on either side, to match other slides that use dashes.

Daw Mill Colliery Ventilation 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 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 No.1 SHAFT No.2 SHAFT No.3 SHAFT. 1911-1972 SEAM EXHAUSTED AFTER 61 YEARS 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 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 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 Drift Floor Section View

Maltby Colliery Ventilation

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

Maltby Colliery Ventilation 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 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 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 Man Doors Bulkhead Return Booster Fan Airlock Doors Intake Fan and Environmental Monitors Tube Bundle Carbon Monoxide Smoke Methane Manometer Delta Press

Kellingley Colliery 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 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 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 Bulkhead Casing Diffuser Inlet Discharge

Centrifugal Booster Fan

Kellingley Colliery Ventilation Intake Bulkhead Booster Fan Return Airlock Doors Airlock Doors Fan and Environmental Monitors Methane Carbon Monoxide Delta Press Temperature

2 x 2 Booster Fans Intake Airlock Doors Bulkhead Return

Kellingley Colliery Ventilation 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 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 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 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

Highland Mine projected ventilation network using only a main fan Unit 3: 9.4 cms Unit 5: 9.4 cms North Mains Summary of Results:   Main fan duty: 200 m3/s at 2.24 kPa Total airpower: 440 kW West Mains Mined Out Area Unit 1: 9.4 cms East Mains Unit 2: 9.4 cms Legend Main Fan North Unit 4: 9.4 cms

Highland Mine projected ventilation network using one booster fan Unit 3: 9.4 cms Unit 5: 9.4 cms North Mains Summary of Results:   Main fan duty: 180 m3/s at 1.37 kPa Booster fan duty: 150 m3/s at 0.57 kPa Total airpower: 330 kW West Mains Mined Out Area 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 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 Total airpower: 230 kW North Mains West Mains Mined Out Area Unit 1: 9.4 cms East Mains Unit 2: 9.4 cms Legend Main Fan Booster Fan 1 North Booster Fan 2 Unit 4: 9.4 cms