Respiratory Protection for Coal Mining

44 Pages·2005·0.39 MB·English

by  Glenn Baxter

3Mining
at your service
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Respiratory Protection for the
Coal Mining Industry
This presentation is specific to the respiratory protection needs of the coal
mining industry. Many of the concepts outlined within are highly relevant to
other industries, but have been placed into a coal mining context.
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Respiratory Protection for Coal
Mining
Session 1 – Airborne Hazards & Exposures
Session 2 – Respirator Selection
Session 3 – Fit and Wear time
Session 4 – Maintenance
Session 1 –Covers the main hazards, health effects and typical exposures
encountered in coal mining. We will cover both gas and particulate hazards,
exposure levels and exposure standards.
Session 2 –In this session we will cover the principles of respirator
selection, the 3 factors to be considered and an overview of some 3M
respirators that fit the selection criteria for the coal mining industry.
Session 3 –Session 3 will cover the correct fitting procedures of the
respirators selected in Session 2. The importance of fit testing, and fit
checks that wearers should conduct each time a respirator is fitted to make
sure it is being correctly worn. Session 3 will also cover the topic of wear
time and its importance to respiratory protection.
Session 4 –Our last session will cover the care and maintenance of
Airstream mining helmets
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Session 1 - Airborne Hazards
In this session we will cover:
•Dusts, Mists and Fumes
•Diesel Particulate Matter
•Diesel Gaseous contaminants
•Exposure Standards
Session 1
When selecting respiratory protection,it is vital to know what airborne
hazards are present in the environment, this session will briefly cover:
Common dusts, mists and fumes encountered in mining environments
Diesel Particulate matter (also known as DPM or DP) and the gaseous
products in diesel emissions
The exposure levels for these contaminants
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Dusts, Mists & Fumes
•Dust
•Crushing, Cutting, Sanding etc
•Eg Coal Dust, Crystalline silica,
•Mist
•Airborne droplets from Spraying etc
•Eg Oil mist
•Fume
•Fire, Hot Work processes
•Eg Welding Fume
Particulates are classified in Australian Standard AS/NZS 1715 into 3 main
types:
Dusts –solid particles generated by mechanical means such as crushing,
cutting & sanding.
Mists – airborne droplets of liquid suspended in air. They are usually
formed by condensation of vapour of by atomisation of a liquid.
Fumes – formed when material from volatilised solid condenses into small
particles. Hot work processes such as welding, soldering and brazing
generate fume.
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Dusts - Sizes
Visible by electron Visible by
Visible by human eye
microscope microscope
Viruses
UnaggregatedWelding fume
Diesel Particulate
Tobacco smoke
Coal Dust
Pollen
Human
hair
Dust
Mists &
Fog Rain
drizzle
0.1 1.0 10 100 1000 10000
Particle diameter, microns (1mm = 1,000 microns)
RespirableRange
Total Inhalable Range
The key aspects of dust mist and fumes lies with the particle sizes typical to
each. Mechanically generated particles such as those from dusts and mists
have a size range that is considerably greater and a larger proportion of non
respirable sized particles.
Thermally generated particles such as fumes on the other hand have a
considerably smaller particle size and a large proportion of respirable size
particles.
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Dusts, Mist & Fumes - Effects
•Coal Dust
–Coal workers pneumoconiosis
•Crystalline Silica
•Silicosis
•Welding fume
•Varies with type of metals in the fume.
Eg galvanised steel – metal fume fever
from Zinc Oxide
Commonly encountered dusts, mists and fumes in coal mining are
Coal Dust –respirable sized particles of coal dust are responsible for the
condition known as coal workers pneumoconiosis. Larger sized particles are
removed from the respiratory tract with no adverse effects. Photo on the
right is of a lung from a person with coal workers pneumoconiosis. Note the
blackened areas of coal dust deposition and large empty spaces in the lung
tissue.
Crystalline silica – Predominantly due to quartz. Respirable sized particles
released from rock. Causes a pulmonary fibrosis where the elasticity and gas
exchange regions of the lung are reduced over time. This increases the
resistance to breathing causing increased strain on the circulatory system.
Welding fume – The effects of welding fume exposure vary depending on
the type of metals being welded. For example welding galvanised steel will
release Zinc Oxide which can cause a temporary illness known as metal
fume fever where influenza like symptoms last for about 48 hours
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Diesel Particulate Matter
•Formed from combustion
• Elemental carbon (EC)
particles with adsorbed
chemicals (OC)
•EC stick together to form
chains or clumps
In the past diesel emissions were not considered to be of great significance.
However, with advances in knowledge and medical science much greater
emphasis is now being placed on exposure to diesel emissions worldwide.
Diesel particulate matter is composed of very small particles ofcarbon
which stick together to form chains or clumps (these are known as the
Elemental carbon or EC component). Stuck to the surface of the EC are
organic compounds formed from the incomplete combustion of diesel (these
are known as the Organic carbon or OC component)
The sizes of the DP is mainly less than 1 micron.
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Diesel Particulate - Effects
•High concentrations cause irritation
•Due to the size and composition of DP it is easily
inhaled and retained in the lungs.
•On the basis of animal studies has been
classified by the International Agency for
Research on Cancer (IARC) as ‘probably
carcinogenic to humans”
Where levels of DP are >0.2mg/m3 eye irritation and discomfort from the
odours are more apparent.
Because DP is so small it is readily inhaled and deposited in the gas
exchange region of the lungs. This also allows the adsorbed OC to be
delivered into the lungs.
The presence of OC which contains many chemicals shown to be
carcinogenic and the results of tests on animals has led the IARC to classify
DP as a group 2A carcinogen “probably carcinogenic to humans”
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Gaseous Diesel Emissions -
Effects
• Carbon Monoxide
– Chemical asphyxiant
• Sulfur Dioxide
– irritant, bronchoconstriction (airway narrowing)
• Oxides of Nitrogen (NO NO )
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– Respiratory irritants
• Aldehydes
–Irritants particularly eyes
Particulates are only one component of the emissions from diesel engines.
The gases and vapours produced have their own effects. Some of the
gaseous constituents are
Carbon Monoxide – (from incomplete combustion) binds with haemoglobin
in the blood and reduces the oxygen carrying capacity.
Sulfur Dioxide – (from the sulfur in the fuel) dissolves in mucous
membranes to form sulfurous acid which acts as an irritant on the
membrane. The increased acid concentration causes the smooth airways to
constrict. Long term exposure can result in chronic bronchitis. Can induce
asthma.
Oxides of Nitrogen: Nitric Oxide and Nitrogen Dioxide (from the nitrogen
in the combustion air) are potent respiratory irritants which are able to
penetrate deep into the lung. The effects of exposure to these agents can take
up to 18 hours to appear
Aldehydes – oxygen containing organic compounds from incomplete
combustion, the two most prevalent being Acrolein and Formaldehyde.
Acrolein and Formaldehyde are also strong irritants to mucous membranes,
the eyes being particularly sensitive
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