Australian Black Coal Industry Coal Services Pty Limited Standing Dust Committee NSW Dust Sampling Results Dust Management Hygiene Issues

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Australian Black Coal IndustryCoal Services Pty
Limited Standing Dust CommitteeNSW Dust
Sampling ResultsDust ManagementHygiene Issues

• Ken Cram
• Gary Mace

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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)

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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

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Respirable Dust Monitoring

• Health Risk
• Dust Sampling Program
• Mineworker Medical Examination

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Standing Dust Committee

• Monitor Sampling Results
• Evaluate Dust Hazards
• Dust Control Methods
• Information and Education

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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

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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

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Order 40Abatement of Dust on Longwalls

• Initiated in 1990
• Dust Results of Previous Longwalls
• Approval Conditions

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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

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Coal Mines Regulation Act 1982 Coal Mines
(Underground) 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
• 0.12 mg of Respirable QUARTZ per m3

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Coal Mines Regulation Act 1982 Coal Mines (Open
Cut) Regulation 1999Coal 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)

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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

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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

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Respirable Dust Results (Including Re- Samples)
1984 - 2004
Exceeding Limit
Mining Method
No. Personal Samples
Number gt3mg/m3
(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
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Respirable Quartz Results (Including Re-Samples)
1984-2004
(including resamples)
Opencut Washeries Longwall Faces Other
Underground
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Content

• 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

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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 -
  gt50 micron
• RESPIRABLE DUST - lt 1 micron 100 penetration
•                                                   
    - lt 5 microns 50 penetration
•                                                   
    -  gt 6 microns dont penetrate
• Penetration depends on speed, mass/ surface area
  and composition
• ie Aerodynamic settling velocity.

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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

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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.

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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.

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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
  HSE)
• 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.

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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.

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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.

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LW 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.

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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

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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.

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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.

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Air Splitting Screens
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Water 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

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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.

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Spray Locations
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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

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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.

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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

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Other Control Measures

• Roadway Dust Control
• Wetting agents (surfactants)
• Water Infusion
• Foam Application
• Scrubber Systems
• Production constraint
• Pick Wear
• PPE

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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

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Dust Suppression Methods
Dust Scrubber Photos
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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 whats already in
  place.

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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.

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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.

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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.

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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

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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.

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Inhalable Dust and DP

• Commonly called total dust, it is monitored due
  to its 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.

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Questions