Transcript Sec_8_Longwall_Dust_Control_Methods.ppt

Control of Airborne
Respirable Dust Hazards:
A Training Program for
Underground Coal Miners
Penn State
The Penn State
Miner Training Program
University Park, PA 16802
March 31, 2003
Raja V. Ramani, Ph.D., P.E, C.M.S.P.
Mark C. Radomsky, Ph.D. MPA, C.M.S.P.
Joseph P. Flick, M.S., C.M.S.P.
CENTERS FOR DISEASE CONTROL
AND PREVENTION
NATIONAL INSTITUTE FOR
OCUPATIONAL SAFETY AND HEALTH
GENERIC MINERAL TECHNOLOGY
CENTER ON RESPIRABLE DUST
PENNSYLVANIA BUREAU
OF DEEP MINE SAFETY
RESPIRABLE DUST
TRAINING PROGRAM
Section 8
LONGWALL DUST
CONTROL METHODS
Longwall Sources of Dust
 Shearer
 Stage Loader/Crusher
 Shields
 Conveyors - AFC/Main Belt
 Air Velocity Reentrainment
Sources of Longwall Dust
Intake
9%
Stage
loader
15%
Shearer
53%
Shields
23%
Typical Longwall Shearer
Dust Control Principles
In order of preference
 Prevention
 Removal
 Suppression
 Isolation
 Dilution
Longwall Dust Control
Prevention reduces dust generation
 Water Infusion
 Foam Infusion
 Deep Cutting
 Slower Speed
 Sharp Bits
Longwall Dust Control
 Removal prevents dust from becoming airborne
 Dust collectors (Scrubbers)
 Suppression makes it difficult for dust to become (or
remain) airborne
 Number of sprays
 Pressure of sprays
 Additives - Surfactants
Longwall Dust Control
Isolation:Keep dust away from miners
Keep miners away from dust
 BIDI/UNIDI
 Cutting sequence: Main cut H to T
Main cut T to H
 Air curtains
Longwall Dust Control
Other forms of Isolation
 Air deflectors
 Spray fans
 Shearer clearer
 Remote control
 Automation
 Personal Protective Devices
Longwall Dust Control
Dilution reduces the ratio of the
amount of dust in the air
 Adequate Air
 Prevent Leakage
 Gob Curtain
 Cut-Out Curtain
 Use of Belt Air
Longwall Dust Problems
1. Inadequate air volume and air velocity
2. Insufficient water volume and pressure
3. Poorly designed external spray systems
4. Inadequate dust control at stage loader and crusher
5. Inadequate protection from shield dust
6. Poor operating practices which keep miners
downwind of the shearer
Longwall Dust Control
 Shearer Dust Control – Shearer design
 Shearer Dust Control – Shearer Sprays
 Shield Dust Control
 Stage Loader/Crusher Dust Control
 Modified Cutting Sequence – Uni-Di
Longwall Dust Control
 Ventilation Controls – Gob curtain
 Ventilation Controls – Wing curtain
 Remote Control and Automation
 Other Methods – e.g. Water infusion, foam, etc
 Other Sources Control – Conveyors, reentrainment
 Personal Protective Equipment – e.g. PAPR
Shearer Water Sprays
Principal Types of Water Sprays Used
in Mine Dust Control
Shearer-Clearer System Operation
Instantaneous Dust Levels With
and Without a Shearer Clearer
Shield Spray System
Stage Loader/Crusher
Ventilation Formulas
Gob Curtain to Reduce Air Leakage
into the Gob at the Headgate
Wing Curtain to Direct Air From
the Headgate Cut-out Area
Water Infusion
Scheme in
a Longwall
Block Prior
to Mining
Multiple Controls in Modern Longwalls
1. Shearer-Cutting Sequence - Deep Cutting
 Slow drum speed, Water sprays
 Pick pushing, Shearer clearer
 Remote control, Scrubbers
2. Shields - Washing Down, Sprays
3. Face/Main Conveyor Sprays
Multiple Controls in Modern Longwalls
[Continued]
4. Stage Loader/Crusher-Banks of Sprays, Scrubber
5. Ventilation - Large Quantities
 Reduce leakage
 Gob curtains
 Cut-out curtains
Multiple Controls in Modern Longwalls
[Continued]
6. Administrative Control - Operational Practices,
Cutting Sequences
7. Personal Protective Devices
Air helmets
Respirators
Proceed to Section 9
Continuous Mining
Dust Control Methods