australian black coal industry coal services pty limited standing dust committee nsw dust sampling...
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Australian Black Coal IndustryCoal Services Pty Limited Standing Dust Committee
NSW Dust Sampling ResultsDust Management
Hygiene Issues
Ken CramGary 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)
AUSTRALIAN COAL DEMAND & SUPPLY
020406080
100120140160180200220240260280300320
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
Mil
lio
n T
on
nes
Stocks Domestic Exports Production
SALEABLE COAL PRODUCTION BY STATES
020406080
100120140160180200220240260280300320
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
Mill
ion
To
nn
es
New South Wales Queensland Other States
MARKET FOR AUSTRALIAN COAL, 2006
Other domestic4%
Overseas exports77%
Domestic power generation
19%
SALEABLE COAL PRODUCTION, AUSTRALIA
020406080
100120140160180200220240260280300320
19
97
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
Mill
ion
To
nn
es
Underground Open Cut
AUSTRALIAN RAW COAL PRODUCTIONBY METHOD OF MINING
0
50
100
150
200
250
300
350
400
450
1983 84 85 86 87 88 89 1990 91 92 93 94 95 96 97 98 99 2000 01 02 03 04 05
Coal Services Pty Limited
Millio
n of
Ton
nes
Open Cut Bord & Pillar Longwall
PRODUCTION FROM LONGWALL FACESAUSTRALIA
0
15
30
45
Coal Services Pty Limited
Mill
ion
of T
onne
s
0
15
30
45
No
of L
ongw
all F
aces
NSW QLD No NSW Faces No QLD Faces
EMPLOYMENT, AUSTRALIAN COAL MINES BY METHOD OF MINING
7 000
9 000
11 000
13 000
15 000
17 000
19 000
21 000
23 0001
99
7
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
At December
Nu
mb
er
of
Em
plo
ye
es
Open Cut Underground
EMPLOYMENT, AUSTRALIAN COAL MINES BY STATES
0
2 000
4 000
6 000
8 000
10 000
12 000
14 000
16 000
18 0001
99
7
19
98
19
99
20
00
20
01
20
02
20
03
20
04
20
05
20
06
At December
Nu
mb
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of
Em
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ye
es
New South Wales Queensland Other States
Coal Services Pty Limited• 2001 NSW Coal Industry Act
– 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-MonthlyMainly 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 DustInhalable DustDiesel Particulate
• Research ProjectsInhalable Coal Dust Exposure LimitsQuartz Exposure Standard for AS 2985Sampling Pump Flow Rate Change for AS 2985Personal Dust Monitor (PDM) U /G Trials
Order 40Abatement of Dust on Longwalls
• Initiated in 1990
• Dust Results of Previous Longwalls
• Approval Conditions
NSW Coal MinesGravimetric 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 2002Coal 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 ServicesRespirable 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 ResultsRespirable Dust Results
(Including Re- Samples) 1984 - 2004(Including Re- Samples) 1984 - 2004
Mining Method
No. Personal Samples
Number >3mg/m3
% Exceeding Limit
Longwall Faces
Other Underground
Open Cut/ Washeries
16 686 1 131 6.8
32 583 531 1.6
3 486 34 1.0
(including resamples)
Respirable Quartz Results Respirable Quartz Results (Including Re-Samples) (Including Re-Samples)
1984-20041984-2004
Opencut Washeries
Longwall Faces
Other Underground
Mining Method
No. Personal Samples
Number >0.15mg/m3
3 486 66
16 686 687
32 583 517
(including resamples)
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
Pneumoconiosis PrevalenceNSW Coal Industry, 1970-2002
0
1
2
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8
1965 1970 1975 1980 1985 1990 1995 2000 2005
Year
Ra
te p
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rkers
Series1
Series2
ContentContent
• 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 SizeDust 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 RisksHealth 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
PneumoconiosisPneumoconiosis• 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.
SilicosisSilicosis
• 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 CoalSilica 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 RisksLowering 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 ExposuresDust 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 ExposuresLW Dust Exposures
• Studies have shown that high dust exposures on longwall mining operations are mainly due to:– 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 MeasuresControl 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 Ventilation as a Control MeasureMeasure
• 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.
VentilationVentilation
• 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 ScreensAir Splitting Screens
Water as a Control MeasureWater as a Control Measure
• 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 MeasureWater 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 LocationsSpray Locations
Face Sprays activated automatically by the Shearer in backs of 10 chocks on return side of the shearer
Canopy sprays autoimatically activated as chock moves
Linkage Spays automatically activated as chock moves
Types of SpraysTypes 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 SpraysTypes 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 SpraysTypes 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 MeasuresOther Control Measures
• Roadway Dust Control• Wetting agents (surfactants)• Water Infusion• Foam Application• Scrubber Systems• Production constraint• Pick Wear• PPE
Dust Suppression MethodsDust 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 MethodsDust Suppression MethodsDust Scrubber Photos
Administrative MeasuresAdministrative 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.
SurfactantsSurfactants
• 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.
PPEPPE
• 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 MonitoringDust 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 PersonalStatic 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 meanResults & 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 DPInhalable 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.
QuestionsQuestions