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Felipe Calizaya Miles Stephens
2010
UTILIZATION OF BOOSTER FANS IN UNDERGROUND
COAL MINES
Stewart Gillies
Univ. of Utah, Salt Lake City, UT
Missouri Univ. of S&T, Rolla, MO
Introduction
Project Objectives
Utilization of Booster Fans
U of U Coal Mine Model
M S&T Experimental Mine
Summary
Outline
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
Introduction
Section A
Section B
Booster FanSurface
FanRegulator
Stopping
Intake
A booster fan decreases main fan pressure & leakage It requires a fan monitoring system
Introduction
Transducer List
M1 Smoke
M2 CO
M3 Air velocity
M4 Diff. pressure
M5 Vibration
M6 Temperature
Project Objectives
Investigate the conditions under which booster fans can be safely used in U/G coal mines
Monitor the performance of booster fans in a laboratory model and an experimental mine
Develop a booster fan selection method
Educate/Train M.S. & Ph.D. students in advanced mine ventilation
Utilization of Booster Fans
In the U.S., booster fans may be used in metal and non-metal underground mines
They are not allowed in U/G coal mines, except in anthracite mines (CFR 75.310)
Currently, booster fans are used in a number of coal mines in Australia, United Kingdom, Poland, India, others
In western U.S. mines, coal is extracted from seams covered with more than 1000 m of overburden, with increased gas and heat flow rates
Ventilation Problems in Coal Mines
In most cases, high pressure main fans are used to supply the required quantities of air to the face
Booster fans can be used to assist main fans in overcoming these adverse conditions
High pressure High air leakage
Planning Example
100 K
120 Kcfm
80 K
Main Fan
Heading
GOB
83 K
Case 1: Determine the fan size(Single- Fan System)
P = 10 in.w.g
Q = 699 kcfm
Planning Example
100 K
120 Kcfm
80 K
Main Fan
Heading
GOB
83 K
P = 7.2 in.w.g
Q = 663 kcfm
Booster Fan
Case 2: Determine the best combination of fan pressures
Main Fan
P = 2.2 in.w.g
Q = 576 kcfm
Booster Fan
Solutions to Sample Problem
1. Single Fan System
Main Fan
H, in.w.g Q, kcfm Power, HP
10.0 698.8 1101.2
2. Two Fan System
Main Fan 7.2 662.7 751.9
Booster Fan 2.2 576.1 199.7
Total Power: 951.6 HP
Total Power: 1101.2 HP
Net Power Saving: 150 HP
The University of Utah’s Coal Mine Model
Model used to study leakage through “stoppings”
U of U Coal Mine Model
This is a 14.6-cm diameter ductwork configured in a common U shaped ventilation system
The intake and return drifts are joined by five cross-cuts (four stoppings and a face)
The system is powered by a 3 kW centrifugal fan equipped with a variable frequency drive
The U of Utah’s Coal Mine Model
Perforated gate valves used to represent stoppings
A Leakage Flow Test
Objective: to study leakage flow through stoppings in a laboratory model
A test is conducted by installing a set of “stoppings” in the model & running the fan
Air pressure measurements (Hs & Hv) are conducted. Then, these are use to calculate leakage flow quantities
Test Results
Total Percent Leakage = 42 %
SIMULATED MINE LEAKAGEStopping Size #1
Fan Setting - 1500 Pa
3.28
2.99
2.87 2.85
2.60
2.80
3.00
3.20
3.40
A B C D
Stopping Location
Leak
age
Qua
ntity
, m3 /m
in
Q (fan) = 28.6 m3/min
Q (face) = 16.6 m3/min
Future Work
This model will be upgraded to include a booster fan, a gas injection system, and a set of ventilation monitors.
Carbon dioxide will be used to simulate the gas generated at the face
Objective: to determine the conditions under which flow recirculation can be avoided
Booster Fan (3 kW)Main Fan (5kW)
Return
Inlet
1.2 mRegulator
?Gas Source
ΔH Ventilation MonitorsCO2
4.5 ftB
GateIn
Out
Reg
.F
AC
E
1-ft
B
Gate
.
In
Out
Ble
eder
1.5 ft9.0 ft
The U of Utah’s Booster Fan Model
Simulated Mine Gob
The Missouri S&T Experimental Mine
The Missouri S&T Experimental Mine is a limestone mine, located outside Rolla, MO
The mine is accessed by two adits and has three raises to surface
It is ventilated by a 30 kW Joy axial fan(Fan duty: Q = 23.6 m3/s @ Ps = 1,000 Pa)
The Missouri S&T Experimental Mine Map
D
D
Initial Plans:
The Missouri S&T Experimental Mine
Upgrade the main fan system
Install two booster fans in bulkheads
Install an electronic monitoring system (To monitor: press, quantity, vibration, bearing T)
Collect data to determine optimal placement of booster fans
Summary
The U of Utah and the Missouri University are investigating the conditions under which booster fans can be used in U.S. U/G coal mines
• Ventilation surveys in two non-U.S. coal mines where B-Fans are used regularly
The project includes:
• Ventilation surveys in two deep and/or extensive U.S. coal mines
Questions?
R
R
DD
R
R
DD
392 Pa751 Pa
Ma
ing
ate
4N
R
R
Main Surface Fan 282 m3/s @ 1054 Pa
50 m3/s
54 m3/s
Borehole Fan 12 m3/s @ 4500 Pa
37 m3/s
R
6 m3/s
X
DD
DD
X
D
DXD
Twin Boosters @ 472 rpm 220 m3/s @ 800 Pa
1154 Pa
Booster Fans at Peabody Energy’s North Goonyella Coal Mine, Australia
Booster Fans at Peabody Energy’s North Goonyella Coal Mine, Australia
Main Fan Duty:
Twin centrifugal fans installed in the main return Each fan powered by a single 600 kW motor Central bypass to maintain ventilation when fan is off
Q = 600,000 cfm @4.2 in.w.g.
Booster Fans’ Duty: Speed: 472 rpm
Q = 465,000 cfm @ 3.2 in.w.g.
Booster Fans at Peabody Energy’s North Goonyella Coal Mine, Australia
Summary
This project also includes:
• Monitor the performance of booster fans in a laboratory model and an experimental mine
• The development of an efficient booster fan selection program
• Training of six graduate students in advanced mine ventilation
Questions?Questions?