1. Control of Airborne Respirable Dust Hazards: A Training Program for Underground Coal Miners The Penn State Miner Training Program University Park, PA 16802 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. March 31, 2003 Penn State

2. 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

3. RESPIRABLE DUST TRAINING PROGRAM Section 8 LONGWALL DUST CONTROL METHODS

4. Longwall Sources of Dust  Shearer  Stage Loader/Crusher  Shields  Conveyors - AFC/Main Belt  Air Velocity Reentrainment

5. Sources of Longwall Dust

6. Typical Longwall Shearer

7. Dust Control Principles In order of preference  Prevention  Removal  Suppression  Isolation  Dilution

8. Longwall Dust Control Prevention reduces dust generation  Water Infusion  Foam Infusion  Deep Cutting  Slower Speed  Sharp Bits

9. 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

10. Longwall Dust Control Isolation:Keep dust away from miners Keep miners away from dust  Air curtains  BIDI/UNIDI  Cutting sequence:Main cut H to T Main cut T to H

11. Longwall Dust Control Other forms of Isolation  Air deflectors  Spray fans  Shearer clearer  Remote control  Automation  Personal Protective Devices

12. 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 Control

13. 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

14. 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

15.  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 Longwall Dust Control

16. Shearer Water Sprays

17. Principal Types of Water Sprays Used in Mine Dust Control

18. Shearer-Clearer System Operation

19. Instantaneous Dust Levels With and Without a Shearer Clearer

20. Shield Spray System

21. Stage Loader/Crusher

22. Ventilation Formulas

23. Gob Curtain to Reduce Air Leakage into the Gob at the Headgate

24. Wing Curtain to Direct Air From the Headgate Cut-out Area

25. Water Infusion Scheme in a Longwall Block Prior to Mining

26. 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

27. 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]

28. 6.Administrative Control - Operational Practices, Cutting Sequences 7.Personal Protective Devices  Air helmets  Respirators Multiple Controls in Modern Longwalls [Continued]

29. Proceed to Section 9 Continuous Mining Dust Control Methods