9. Mine Aerosol Measurements

Health harzard in exposure to respirable mineral aerosol:

1. Pneumoconiosis โรคปอด2. Asthma โรคหืด3. Emphysema การพองลมของเนื้�อเยื่�อหืรอถุ�งลม4. Silicosis โรคปอดจากการสู�ดฝุ่��นื้

Some women in mine area lost “seven” husbands through diseases.

- - 1. Room and pillar mining- CCCCCCCCCCCC- Continuous

2 . Longwall mining

Underground coal mining process -> Popular

Room-and-pillar mining: conventional

1. Undercut coal slot2. Drill holes to the coal3. Load explosives to the holes4. Blast down the coal face5. Transport blasted coal

7%

Room-and-pillar mining: continuous

1. Continuous mining machine cuts coal from the face2. Loads it to shuttle car3. Transport to material transfer system

60%

Longwall mining

1. Shearing machine CCCCCCC CCCC CCCC C CCCCCCCC CCCCC

2. Cut coal is conveyed CC CCC CCCC C CC conveyor

3 . Transport to material transfer system

33%Most efficient and productive

Respirable dust sources

1. Drilling2. Cutting3. Blasting4. Loading5. Coal transport6. Emission from diesel-powered equipment

Typical level of dust concentration

Longwall is highest. conventional is lowest.

Dust concentration depends on:

1. Ventilation2. Dust control, i.e. spray3. Type of coal4. 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 90 10. More than % of mass is smaller than . micron (aerodynamic

diameter) 3. Can penetrate to the deepest regions of the lung 4. Causes lung disease

Physical characteristics of mine aerosol

1 0001 008. Nuclei mode; . to . micron- primary aerosol, i.e. diesel engine emission- secondary aerosol formed by coagulation of primary

aer osol 2 008 10. Accumulation mode; . to . micron

- emi ssi on- coagul at i on and condensat i on of nucl ei aer osol

3 10 40. Coarse mode; . to 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 dust2. Quartz3. Asbestos4. Radon daughters5. Welding fumes

CCC CCCCCCCC CCCCCCCCCC CCCC CCC CCCC..,

- preclassified by a cyclone

- col l ect dust on a fi l t er

- det er mi ne mass concent r at i on

- - analyze quartz by X ray diffraction

Permissible Exposure Limit (PEL) by MSHA

- 1 5. Respirable dust > mg/m3

- 2 100. Respirable quartz > / 3

- 19851990Respirable quartz statistics for selected commodity,

Regulatory - Coal

Can use same personal respirable dust sampler

- preclassified by a cyclone- col l ect dust on a fi l t er- det er mi ne mass concent r at i oC- analyze quartz by Fourier Tran

- sform Infrared (FT IR) spectrometryPermissible Exposure Limit (PEL) by MSHA

- 1 2. Respirable dust > mg/m3

- 2 100. Respirable quartz > / 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- 290Series Andersen samplers- CCC: 2- 8No of stages:- Cut size 0.5 to 20 micron

- - Micro Orifice, Uniform Deposit Impactor (MOUDI)- C CC1 00

- 30Flowrate: lpm- 10No of stages:- Cut size 0.056 to 18 micron

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

90More than % of diesel exhaust aerosol are submicron. - 40 60This accounts for % of the respirable mass concentration.

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

10Less than % of the respirable mass concentration.

Diesel aerosol sampling and analysis

Measurement parameters1. Mass concentration2. Carbon content

Personal diesel exhaust aerosol sampler- 3 stage- 1Stage : cyclone- - 2 4Stage : nozzle impactor 08cut size = . micron- 3Stage : 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 1. Mie RAM

- Uses cyclone to remove water droplets a nd ensure respirable dust

sampl i ng- Pulsed Gallium arsenide light source

- 880Narrow ban light with center of nC

- 45Angular detection: o - 95o , forwardCCCCCCCCC

- Silicon light detector

Mie RAM-1

2. Tapered Element Oscillating Microbala nce (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 CCCCCCC- Frequency of vibration i s a f unct i on of mass