Transcript Coal Services Dust Committee & Results

Australian Black Coal Industry
Coal Services Pty Limited
Standing Dust Committee
NSW Dust Sampling Results
Dust Management
Hygiene Issues
Ken Cram
Gary Mace
OVERVIEW 2006
Record Year for Australian Black Coal Industry
Increased:
–
–
–
–
Production
Exports and $Value
Domestic Consumption
Number of Mineworkers Employed
December 2006 – 118 Black Coal Mines
• 74 Opencut Mines
• 44 Underground Mines ( 29 Longwalls Faces)
Stocks
Domestic
Exports
Production
2006
2005
2004
2003
2002
2001
2000
1999
1998
320
300
280
260
240
220
200
180
160
140
120
100
80
60
40
20
0
1997
Million Tonnes
AUSTRALIAN COAL DEMAND & SUPPLY
New South Wales
Queensland
Other States
2006
2005
2004
2003
2002
2001
2000
1999
1998
320
300
280
260
240
220
200
180
160
140
120
100
80
60
40
20
0
1997
Million Tonnes
SALEABLE COAL PRODUCTION BY STATES
MARKET FOR AUSTRALIAN COAL, 2006
Dom estic pow er
generation
19%
Other dom estic
4%
Overseas exports
77%
Underground
Open Cut
2006
2005
2004
2003
2002
2001
2000
1999
1998
320
300
280
260
240
220
200
180
160
140
120
100
80
60
40
20
0
1997
Million Tonnes
SALEABLE COAL PRODUCTION, AUSTRALIA
AUSTRALIAN RAW COAL PRODUCTION
BY METHOD OF MINING
450
400
Million of Tonnes
350
300
250
200
150
100
50
0
1983 84
85
86
87
Coal Services Pty Limited
88
89 1990 91
92
Open Cut
93
94
95
Bord & Pillar
96
97
98
Longwall
99 2000 01
02
03
04
05
NSW
Coal Services Pty Limited
QLD
No NSW Faces
No QLD Faces
06
05
03
04
02
No of Longwall Faces
0
99
20
00
01
0
98
15
96
97
15
94
95
30
92
93
30
89
19
90
91
45
88
45
19
86
87
Million of Tonnes
PRODUCTION FROM LONGWALL FACES
AUSTRALIA
EMPLOYMENT, AUSTRALIAN COAL MINES
BY METHOD OF MINING
23 000
19 000
17 000
15 000
13 000
11 000
9 000
At December
Open Cut
Underground
2006
2005
2004
2003
2002
2001
2000
1999
1998
7 000
1997
Number of Employees
21 000
EMPLOYMENT, AUSTRALIAN COAL MINES
BY STATES
18 000
14 000
12 000
10 000
8 000
6 000
4 000
2 000
At December
New South Wales
Queensland
Other States
2006
2005
2004
2003
2002
2001
2000
1999
1998
0
1997
Number of Employees
16 000
Coal Services Pty Limited
• 2001 NSW Coal Industry Act
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–
–
–
–
Workers’ Compensation Insurance
Occupational Health & Rehabilitation
Occupational Hygiene (including coal dust monitoring)
Mines Rescue Emergency Response
Coal Industry Statistics
• Ownership
– NSW Minerals Council
– CFMEU
• Subsidiary Companies
– Coal Mines Insurance Pty Ltd
– Mines Rescue Pty Ltd
Respirable Dust Monitoring
• Health Risk
• Dust Sampling Program
• Mineworker Medical Examination
Standing Dust Committee
• Monitor Sampling Results
• Evaluate Dust Hazards
• Dust Control Methods
• Information and Education
The Committee Meets Bi-Monthly
Mainly at Mine Sites
Since CSPL in January 2002 meetings at:
• 25 Underground Coal Mines
• 5 Open Cut Coal Mines
• Southern Mines Rescue Station
• Testsafe - Londonderry
• Mine Safety Technology Centre - Thornton
Committee Initiatives
• Introduction of Gravimetric Dust Sampling
• Setting of Current Exposure Standards
• CMHS Act Regulations 2006 recommendations:
Respirable Dust
Inhalable Dust
Diesel Particulate
• Research Projects
Inhalable Coal Dust Exposure Limits
Quartz Exposure Standard for AS 2985
Sampling Pump Flow Rate Change for AS 2985
Personal Dust Monitor (PDM) U /G Trials
Order 40
Abatement of Dust on Longwalls
• Initiated in 1990
• Dust Results of Previous Longwalls
• Approval Conditions
NSW Coal Mines
Gravimetric Personal Dust Sampling
From March 1984 to December 2004
The Specified Limits were:
• 3 mg of Respirable DUST per m3
• 0.15 mg of Respirable QUARTZ per m3
Coal Mines Regulation Act 1982
Coal Mines (Underground) Regulation 1999
Coal Mine Health and Safety Act 2002
Coal Mine Health and Safety Regulation 2006
Specified Limits for Airborne Dust
Since January 2005
 2.5 mg of Respirable DUST per m3
 0.12 mg of Respirable QUARTZ per m3
Coal Mines Regulation Act 1982
Coal Mines (Open Cut) Regulation 1999
Coal Mine Health and Safety Act 2002
Coal Mine Health and Safety Regulation 2006
Specified Limits for Airborne Dust
Since January 2005
 2.5 mg of Respirable DUST per m3
 0.1 mg of Respirable QUARTZ per m3
(includes surface parts of underground mines)
Dust Sampling 5 People
• All Production Shifts:– Continuous Miners – once per year
– Longwalls – twice per year
• All Others (once per year):
– Other Underground
– Surface Washeries and Plants
– Open Cut Mines
Coal Services
Respirable Dust Sampling
March 1984 – December 2004
• Collected almost 53,000 personal dust samples
• Sampled over 10,000 mining locations
62% other underground (mainly CM panels)
31% underground longwall faces
7% surface open cuts and coal prep plants
Respirable Dust Results
(Including Re- Samples) 1984 - 2004
Mining
Method
No. Personal
Samples
Number
>3mg/m3
% Exceeding
Limit
(including resamples)
Longwall
Faces
Other
Underground
Open Cut/
Washeries
16 686
1 131
6.8
32 583
531
1.6
3 486
34
1.0
Respirable Quartz Results
(Including Re-Samples)
1984-2004
Mining
Method
No. Personal
Samples
Number
>0.15mg/m3
(including resamples)
Opencut
Washeries
Longwall
Faces
Other
Underground
3 486
66
16 686
687
32 583
517
Pneumoconiosis Prevalence
NSW Coal Industry, 1970-2002
Rate per hundred mineworkers
8
7
6
5
Series1
Series2
4
3
2
1
0
1965
1970
1975
1980
1985
1990
1995
2000
2005
Year
The ILO classification of x-rays is a method of grading based on x-ray appearance and may be
in practical terms interpreted as the following:ILO+1 = people with diagnostic features of dust exposure but no clinical symptoms.
ILO +2 = People with more severe dust exposure than above and likely to have symptoms
Content
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Dust Size
Health Risks – CWP
Silicosis
Lowering health Risks
Dust Exposures
Reducing Dust Exposure
Control Measures
Ventilation as a Control
Measure
• Water as a Control
Measure
• Other Control Measures
• Dust Suppression
Methods.
• Administrative Measures
• Surfactants
• PPE
• Dust Monitoring – Static v
Personal
• Results & what they
mean
• Inhalable Dust and DP
Dust Size
• Pneumoconiosis can be prevented provided exposure to
respirable coal dust is maintained below statutory levels –
2.5mg/m3, extensive monitoring programs, appropriate
engineering and procedural controls.
• AIRBORNE DUST YOU SEE - Generally inhalable - >50 micron
• RESPIRABLE DUST
- < 1 micron 100% penetration
- < 5 microns 50% penetration
- > 6 microns don’t penetrate
• Penetration depends on speed, mass/ surface area and
composition
• ie Aerodynamic settling velocity.
Health Risks
• The health risk to mine workers has long been acknowledged
as being related to prolonged exposure to high concentrations
of respirable coal dust which can lead to pneumoconiosis and
when mining high quartz content material silicosis.
• Coal mining has historically been associated with the
occurrence of disabling chest diseases.
• ILO Classification system, the international standard, is the
system used by Coal Services to grade pneumoconiosis on
chest x rays of coal miners.
• Under this system there are 4 major categories used to grade
the severity of pneumoconiosis.
• Category 0 is the normal state
•
1 mild - unaware of presence, normal activities
•
2 moderate - become symptomatic
•
3 severe
Pneumoconiosis
• Coal Workers pneumoconiosis results from the gradual
accumulation of coal dust particles within the lung tissue,
usually over a period of many years.
• Most of the dust that is inhaled does not lodge in the lungs.
• The larger particles are trapped in the nose and throat and the
very smallest particles are exhaled in the same breath.
• Only the particles in the 0.5 - 7 micron size range are
deposited and the lungs have special clearance mechanisms
to remove most of these particles in the course of the next few
days or weeks.
• The dust which is not cleared aggregates to form nodules
which can be seen on X Ray or PM. Generally at least 20 -30
years of exposure is necessary to produce any significant
degree of disease.
Silicosis
• QUARTZ ( SILICA) Exposure = SILICOSIS IF
EXPOSURES ARE SIGNIFICANT
• A relationship between silica exposure and lung
cancer.
• In coal mines free silica in coal is low however
mines with stone intrusions or where brushing of
the floor is common may have a problem.
• Exposures must be kept below - 0.12mg per
cubic metre of air.
• Silica is more irritating to lung tissue because of
its chemical nature.
Silica and Coal
• NOHSC and UWA have acknowledged that ‘coal dust is capable
of inhibiting the fibrogenic effect of crystalline silica &
therefore possibly its carcinogenicity’ (IARC 1997).
• As a result they initially stated that the coal industry should
have a separate study to establish a suitable exposure
standard.
• In the latest documentation from the NOHSC this important
factor has been overlooked.
• Overseas studies have linked excessively high silica exposure
in coal mines to an increase in levels of silicosis. (Scottish coal
mine –UK HS&E)
• Silica is more prevalent an issue in the northern districts
particularly in certain seams in the Singleton area.
• Coal Services Health has been conducting far more silica
analysis in recent years to ensure that workers health is not
compromised.
Lowering Health Risks
• When JCB established in 1948 pneumoconiosis was
prevalent • 16% all categories, 4.2% - 2 or worse.
• Today prevalence so low that no new cases of
pneumoconiosis have been detected in the last 10 years
( Standing Dust Committee 1997).
• The incidence of pneumoconiosis in NSW is among the
lowest in the world. In sharp contrast to the USA where
unfunded black lung liabilities reach some $15 billion.
• Why does NSW have such a good record?
• Independent monitoring, improvements in engineering
(ventilation), safe work practices, education, PPE.
Dust Exposures
• Dust concentration depends on the method of mining,
nature of the mineral being worked and dust suppression
techniques in use.
• Success in combating pneumoconiosis in NSW and QLD
had largely been due to the fact that coal was almost
exclusively won by using continuous miners and shuttle
cars where all personnel work in intake air.
• Longwall mining is potentially a more difficult
environment to control. In longwall mining not only is the
dust concentration higher due to the more rapid
excavation rate but the pattern of movement of men make
the system more difficult to analyse.
• Dust below 5 microns is respirable - no significant weight
or inertia and hence can remain suspended for longer
periods in the atmosphere.
LW Dust Exposures
• Studies have shown that high dust
exposures on longwall mining operations are
mainly due to:
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Inadequate air volume and velocity;
Insufficient water quantity and pressure;
Poorly designed external water spray systems;
Lack of dust control at the stageloader and
crusher;
– Dust generated during support movement;
– Cutting sequences that position face workers
downwind of the cutting machine.
Control Measures
• Ventilation
– Volume
– Goaf Curtains
– Air Splitters (Barriers, Batwings)
• Water
– Optimised delivery
– Sprays – types and location
• Administrative Measures
– Interrogate process and tasks of high exposure
– Cutting sequences
– Operator location
Ventilation as a Control
Measure
• Ventilation has probably been the most
significant factor in reducing excessive exposure
to dust.
• It can be used simply to keep people in clean air
while moving dust away from the work area.
• Careful observation of the work area and simple
ventilation design can help ensure that available
air can be used to effectively isolate the person
from the exposure.
• In more difficult situations mechanical sources
may be required ie ventilation fans.
Ventilation
• Ventilation should be considered the
PRIMARY method of controlling dust.
• Adequate quantities of air must be available
to dilute and carry or direct the airborne dust
away from the operators work area.
• In addition to the quantity of air, other
engineering controls including brattice
curtains, flexible (eg rubber belt) air splitting
devices can be used to effectively direct the
air.
Air Splitting Screens
Water as a Control Measure
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Airflow – direction and velocity
Droplet size – Spray type
Dust Particle size – primarily respirable or inhalable
Electrostatic charge
Proximity to breakage – location of sprays
Water quality
Water volume
Maintenance – no. of sprays operational
Drainage
Water as a Control Measure
• Optimising water delivery may require
– Increasing pump capacity for increased flow
and pressure
– Increasing line sizes to decrease pressure
and maintenance downtime
– Improving water quality by using filtering
devices to reduce maintenance.
– Reviewing the type of sprays, their location
and effectiveness.
Spray Locations
Types of Sprays
• Hollow cone sprays
can be used for
external shearer
sprays, shearer
clearer, crusher &
transfer points.
• Atomising sprays are
the best for dust
scrubbing, however
are susceptible to
damage and fouling
Types of Sprays
• Venturi sprays are may
be either hollow cone or
atomising enclosed in a
shroud where air is drawn
through to increase
pressure a lower droplet
size.
• Full cone produce a
circular coverage at
higher velocity and larger
droplet size – best for
wetting coal pre transfer
points.
Types of Sprays
• Flat spray nozzles
produce a rectangular
spray pattern of large
droplets at high velocity –
best for transfer points
and under conveyor wiper
systems
• Solid stream – essentially
a flat spray with a circular
spray pattern – best for
direct wetting eg pick and
drum sprays
Other Control Measures
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Roadway Dust Control
Wetting agents (surfactants)
Water Infusion
Foam Application
Scrubber Systems
Production constraint
Pick Wear
PPE
Dust Suppression Methods
BSL
• Curtains in the
throat of the BSL
& improved
jointing to
minimise dust
make
Dust Scrubber
• (Extracts dust
from the crusher
& the discharge
point
Dust Suppression Methods
Dust Scrubber Photos
Administrative Measures
• Interrogating the process
• Review of work procedures across all shifts
• Review monitoring results (Is there a difference and if so
– why?)
• Interrogation of operator positioning using Hund
survey to highlight potential exposures and
reduction of the same.
• Utilise both on-site engineering operational and
external resources to optimise what’s already in
place.
Surfactants
• The effectiveness of water to reduce dust can be
enhanced by the use of a surfactant or softener.
• This chemical compound alters the surface
tension of the water to allow it to trap more dust.
• Atomising the water provides a greater surface
area to make contact with the dust.
• All factors that apply to effective water usage
apply to water sprays used in conjunction with a
surfactant.
• The concentration of the surfactant should be
adequately controlled.
PPE
• Dust respirators should only be used as the last line
of defence and must not take the place of prevention
of dust suppression techniques.
• All respirators must be capable of filtering the dust
to provide relatively clean air to the user with low
resistance to breathing. Fitting must be adjusted to
exclude contaminated air during inhalation. Facial
hair or beards may adversely affect the efficiency of
the seal on respirators.
• It should NOT BE ASSUMED that dust respirators
can be used when there is a deficiency in O2 or
where the contaminant is highly toxic.
Dust Monitoring
• It is the weight of the dust not the no. of particles
retained by the lungs that is the critical factor in the
occurrence of pneumoconiosis.
• CMHSA 2002 and 2006 Regs have maintained the
requirement for statutory personal dust monitoring.
• Now includes Inhalable dust.
• Personal samplers have been adopted in Australia as gravimetric airborne dust sampling is to monitor
the exposure of individuals to respirable dust for
medical purposes. Sampling from a fixed point in the
gate road (UK) does not accurately reflect the
exposure of individual workers.
Static v Personal
• Static monitoring can be used as a measure of changes
in engineering controls to measure effectiveness.
• Static monitoring does not meet exposure monitoring for
regulatory purposes.
• Personal monitoring consists of a vertical cyclone
elutriator placed in breathing zone, attached to pump
with specific flow rate. Fine dust settles on filter paper,
heavy dust falls to bottom. The filter is weighed gravimetric testing.
• Quartz measured by infrared spectrometry or X ray
diffractometry.
SPECIFIED LIMITS
 2.5mg of respirable DUST per cubic metre
0.12mg of respirable QUARTZ per cubic metre
Results & what they mean
• TWA – Time weighted Average – provides a measure of
a persons exposure not just for one shift but refers to an
eight hour day, 5 days per week (ie 40hr) over a forty
year working life.
• Current exposure standards were modified in 2004
following changes to the Australian Standard for
measuring respirable dust.
• Increased flow rate of pumps reduces cut off size on
respirable cyclone – therefore less dust.
• CSH conducted a study using sixty paired samples for
dust and silica to determine the effect of the change to
AS2985 – leading to the reduction of the exposure
standard in NSW coal.
Inhalable Dust and DP
• Commonly called total dust, it is monitored due
to it’s ability to irritate the eyes nose and throat.
(increased incidence of occupational asthma, bronchitis etc)
• Required to by monitored in NSW – current
exposure std not set by DPI, however is inferred
by NOHSC (ASCC) as 10mg/m3.
• DP is a suspected carcinogen.
• Required to by monitored in NSW – MDG29 –
exposure standard established 0.1mg/m3.
Questions