Presentation on theme: "9. Mine Aerosol Measurements Health harzard in exposure to respirable mineral aerosol: 1. Pneumoconiosis โรคปอด 2. Asthma โรคหืด 3. Emphysema การพองลมของเนื้อเยื่อหรือถุงลม."— Presentation transcript:
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
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
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