9. Mine Aerosol Measurements

1. 9. Mine Aerosol Measurements Health harzard in exposure to respirable mineral aerosol: 1. Pneumoconiosis โรคปอด 2. Asthma โรคหืด 3. Emphysema การพองลมของเนื้อเยื่อหรือถุงลม 4. Silicosis โรคปอดจากการสูดฝุ่น Some women in mine area lost “seven” husbands through diseases.

2. Underground coal mining process -> Popular 1. Room-and-pillar mining - Conventional - Continuous 2. Longwall mining

3. Room-and-pillar mining: conventional 7% 1. Undercut coal slot 2. Drill holes to the coal 3. Load explosives to the holes 4. Blast down the coal face 5. Transport blasted coal

4. Room-and-pillar mining: continuous 60% 1. Continuous mining machine cuts coal from the face 2. Loads it to shuttle car 3. Transport to material transfer system

5. Longwall mining 33% Most efficient and productive 1. Shearing machine removes coal from a longwall panel 2. Cut coal is conveyed by the drums to conveyor 3. Transport to material transfer system

6. Respirable dust sources 1. Drilling 2. Cutting 3. Blasting 4. Loading 5. Coal transport 6. Emission from diesel-powered equipment

7. Dust concentration depends on: 1. Ventilation 2. Dust control, i.e. spray 3. Type of coal 4. Rate of coal removal Typical level of dust concentration Longwall is highest. conventional is lowest.

8. Surface non-coal mining process Use conventional method for 90% Sources of aerosol 1. Drilling 2. Material handling 3. Diesel-powered haulage vehicles 4. Dust entrainment during load-haul-dump operations 5. Reentrainment from floor and wall due to traffic

9. Diesel exhaust aerosol 1. Respirable 2. More than 90% of mass is smaller than 1.0 micron (aerodynamic diameter) 3. Can penetrate to the deepest regions of the lung 4. Causes lung disease

11. Physical characteristics of mine aerosol 1. Nuclei mode; 0.001 to 0.08 micron - primary aerosol, i.e. diesel engine emission - secondary aerosol formed by coagulation of primary aerosol 2. Accumulation mode; 0.08 to 1.0 micron - emission - coagulation and condensation of nuclei aerosol 3. Coarse mode; 1.0 to 40 micron - mechanical process, i.e. rock fracture and bulk material handling - Reentrainment during load-haul-dump operations

12. Size distribution of a mine aerosol.

13. Mass size distribution of a mine aerosol in a diesel-equipped mine.

14. Mass size distribution of a mine aerosol in an all electric-equipped mine.

15. Compliance measurement and regulatory environment Regulatory - Metals and nonmetal 1. Total dust 2. Quartz 3. Asbestos 4. Radon daughters 5. Welding fumes

16. E.g., use personal respirable dust sampler - preclassified by a cyclone - collect dust on a filter - determine mass concentration - analyze quartz by X-ray diffraction

17. Permissible Exposure Limit (PEL) by MSHA 1. Respirable dust -> 5 mg/m3 2. Respirable quartz -> 100 mg/m3

18. Respirable quartz statistics for selected commodity, 1985 - 1990

19. Regulatory - Coal Can use same personal respirable dust sampler - preclassified by a cyclone - collect dust on a filter - determine mass concentration - analyze quartz by Fourier Transform Infrared (FT-IR) spectrometry Permissible Exposure Limit (PEL) by MSHA 1. Respirable dust -> 2 mg/m3 2. Respirable quartz -> 100 mg/m3

20. Diesel exhaust Potential occupational carcinogen PEL for diesel exhaust was under developing (1992)

21. Research aerosol measurements 1. Characterize aerosol mass as a function of size 2. Characterize quartz, trace elements and carbon as a function of size 3. Measurement of diesel exhaust aerosol

22. Size-selective sampling Marple personal impactor - Series 290 Andersen samplers - Flowrate: 2 lpm - No of stages: 8 - Cut size 0.5 to 20 micron Micro-Orifice, Uniform-Deposit Impactor (MOUDI) - Model 100 MSP - Flowrate: 30 lpm - No of stages: 10 - Cut size 0.056 to 18 micron

23. More than 90% of diesel exhaust aerosol are submicron. This accounts for 40 - 60% of the respirable mass concentration. Mass size distribution of a mine aerosol in a diesel-equipped mine.

24. Less than 10% of the respirable mass concentration. Mass size distribution of a mine aerosol in an all electric-equipped mine.

25. Diesel aerosol sampling and analysis Measurement parameters 1. Mass concentration 2. Carbon content Personal diesel exhaust aerosol sampler - 3 stage - Stage 1: cyclone - Stage 2: 4-nozzle impactor cut size = 0.8 micron - Stage 3: Filter

26. Mass concentration: Gravimetric analysis Cumulative frequency plot of respirable aerosol concentrations in continuous mining operations using diesel-equipped haulage vehicles.

27. Cumulative frequency plot of respirable diesel aerosol concentrations in continuous mining operations using diesel-equipped haulage vehicles.

28. Real time measurements Light scattering Instrument 1. Mie RAM-1 - Uses cyclone to remove water droplets and ensure respirable dust sampling - Pulsed Gallium arsenide light source - Narrow ban light with center of 880 nm - Angular detection: 45o - 95o, forward direction - Silicon light detector

29. Mie RAM-1

30. 2. Tapered Element Oscillating Microbalance (TEOM) - Uses cyclone to remove non- respirable dust - Filter collects repirable dust - Air flows through the tapered tube at 2 lpm - Mass is weight by vibrating element - Frequency of vibration is a function of mass

31. Sin Jia Yoo E Sin Nee Huad Chai