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.

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

Room-and-pillar mining: conventional 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 7%

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

Longwall mining 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 33% Most efficient and productive

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

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

Use conventional method for 90% Surface non-coal mining process 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

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

Physical characteristics of mine aerosol 1. Nuclei mode; 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

Size distribution of a mine aerosol.

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

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

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

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

Permissible Exposure Limit (PEL) by MSHA 1. Respirable dust -> 5 mg/m 3 2. Respirable quartz -> 100  g/m 3

Respirable quartz statistics for selected commodity,

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/m 3 2. Respirable quartz -> 100  g/m 3

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

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

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 to 18 micron

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

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

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

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

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

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: 45 o - 95 o, forward direction - Silicon light detector

Mie RAM-1

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