Mine Ventilation

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Mine Ventilation

• Risks Controls
• Jason Wagstaffe
• Wagstaffe Associates

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VENTILATION HAZARDS
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Ventilation Hazards

• Sources of potential harm or situations with a
  potential to cause loss include
• Gas
• Dust particulate
• Spontaneous combustion
• Frictional ignition
• Windblast
• Heat
• Poor / inadequate ventilation
• Poor ventilation management
• Inadequate ventilation knowledge

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VENTILATION RISK PREDICTION
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Ventilation Risk Prediction

• Each mine should undertake a Hazard Analysis
  Risk Assessment of the Ventilation Hazards.
• The Hazard Analysis will need to encompass (Not
  limited to)
• Historical records of the mines ventilation
  systems including gas trends
• Existing Primary Auxiliary ventilation systems
  and its adequacy as the mine expands.
• Changes in mining conditions or mine design which
  may lead to hazards such as Spon.Comb or
  Outbursts having a greater influence.
• Coal seam and adjacent strata properties.
• Methods of mining.
• The magnitude of the risk will determine how to
  approach the implementation of controls.

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VENTILATION RISKS
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Ventilation Risks

• Ventilation hazards can be broken into their
  associated risks.
• GAS
• Inrush, Outburst, ignition, explosion,
  asphyxiation.
• DUST DIESEL EMISSION PARTICULATE
• Airborne dust Respirable / Inhalable
  Dangerous Float Dust.
• Diesel particulate Respirable unknown health
  issues.
• SPONTANEOUS COMBUSTION
• Heating, Fire, Explosion.

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Ventilation Risks (Cont)

• FRICTIONAL IGNITION
• Fire, Gas Explosion, Dust Explosion
• WINDBLAST
• Damage to ventilation appliances and mine
  equipment, Personnel injury.
• HEAT
• Dehydration, Exhaustion, Injury.
• POOR / INADEQUATE VENTILATION
• Frictional Ignition, Spontaneous Combustion,
  Heat, Dust Particulate Contamination, Gas
  issues.

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Ventilation Risks (Cont)

• POOR VENTILATION MANAGEMENT
• Differential Pressure Issues,
• High inefficiencies,
• High running costs,
• Financial loss,
• Injuries sustained by employees in the act of
  working with or around ventilation appliances.

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VENTILATION RISK CONTROL
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Risk Control

• GAS
• Regular Inspections to ensure compliance with
  legislative standards.
• Well maintained and calibrated gas detection
  equipment. (Both Hand held, this still includes
  the Locked Oil Flame Safety Lamp, telemetric
  instruments)
• Sufficient Air quantities for dilution.
• Gas drainage (where applicable large gas
  reservoirs)
• Gas régime / reservoir modeling
• Have systems in place that can deal with large
  quantities of gas if it is required.
• Management Plan with triggers and response
  action plans.

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Risk Control (Cont)

• DUST
• Airborne Respirable Dust controlled via dust
  extraction units. (New Technology Now Available)
• Easier to keep dust from becoming suspended then
  it is to eliminate or control once in suspension.
• Sprays machine mounted and fixed systems
• Wet drilling
• Too much air velocity can create dust issues.
• Pre-drained coal may require water injection to
  assist with dust suppression.
• An array of Wetting agents are available to
  assist with dust suppression.
• Limit employee exposure to dust.

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Risk Control (Cont)

• DIESEL EMISSION PARTICULATE
• Wet or Dry filtration systems
• Catalytic converters, Ceramic filters.
• Air quantities sufficient to dilute emissions.
• Well maintained diesel fleet with regular testing
  of exhaust systems
• Ventilate Dead ends and Blind Stubs if
  personnel are working in these places with diesel
  powered machines.
• Clean fuel technology is now more readily
  available. (The current technology has improved
  to a point where excessive engine wear or damage
  due to fuel additives is not an issue).
• Consider decreasing the diesel fleet and
  increasing battery powered fleet.

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Risk Control (Cont)

• SPONTANEOUS COMBUSTION
• Regular inspections using both handheld detection
  equipment and body senses. (Mine Inspection
  System)
• Mine Design / Ventilation Layout must take Spon.
  Comb. into consideration.
• Long term air stream analysis trending.
• Tube bundle gas detection systems may be worth
  considering.
• Ventilation pressures need to be watched
  carefully. High differential pressures across
  pillars and slack coal will cause issues.
• Ventilation Appliances need to be well
  maintained.
• Management Plan - Triggers and Response Action
  Plans.

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Risk Control (Cont)

• FRICTIONAL IGNITION
• Sharp Cutting Picks
• Good sprays
• Air velocities capable of eliminating
  accumulations of gas
• Operators must trained and be vigilant. Regular
  revision of training for operators will assist in
  maintaining knowledge base.
• Try not to cut roof / floor stone
• Minimise depth of cut in high flammable gas zones
• Ready access to fire fighting equipment in
  working order.
• Management Plan.

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Risk Control (Cont)

• WINDBLAST
• High standard of ventilation appliances required.
• Mine plan needs to focus on minimising the
  windblast effect by having multiple entries /
  exits for air to travel.
• Consider pressure relief doors in appliances that
  are adjacent to Windblast zone areas.
• Operators need to be vigilant.
• Management Plan - Triggers and Response Action
  Plans.

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Risk Control (Cont)

• HEAT
• Maintain reasonable air velocities for cooling
  effect.
• Minimise radiated heat. Especially in single
  entries.
• Operators must be educated in hydration
  principles.
• Regular humidity checks and monitoring.
• Consider installation of hydraulically driven
  fans for roof bolting machines to create cooling
  velocities for operators.
• Management must understand the physiological
  issued that are created when heat is an issue.
• Consider air refrigeration.

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Risk Control (Cont)

• VENTILATION CONTROLS
• Include, but are not limited to
• Auxiliary Fans
• Dust Extractors
• Regulators
• Overcasts
• Permanent Temporary Stoppings.
• Venturis
• Brattice
• Booster Fans Small Large

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Risk Control (Cont)

• VENTILATION STRUCTURE INTEGRITY
• Structures include Seals, Permanent Temporary
  Stoppings and overcasts.
• Structure integrity is critical for operations
  that mine seams with large gas reservoirs or have
  a propensity for Spontaneous Combustion.
• Consider Keying into ribs to ensure minimal
  leakage past structures.
• Consider Grouting or P.U.R. injection of coal
  pillars to assist with structure integrity.
  Especially in areas of high differential pressure.

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Risk Control (Cont)

• MINES DEPARTMENT GUIDELINES
• 1999 - Mineral Resources Released DRAFT version
  of MDG 1023 Ventilation Control System
  Guideline for comment.
• Prepared by Dr. Roy Moreby Associate Professor
  UNSW
• No longer listed on the Department list of
  available guidelines.
• A useful tool in developing a systematic approach
  to ventilation risk control.
• MDG 1003 Windblast Code of Practice
• MDG 1006 Spontaneous Combustion Management Code

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Risk Control (Cont)

• VENTILATION MANAGEMENT PLANS
• Need to be short and concise, but contain all the
  information a person will need to manage the
  individual risk/s.
• The reasoning that went into the creation of the
  Management Plan needs to be documented , but
  doesnt need to appear in the Management Plan
  itself.
• Only work if people read and UNDERSTAND them.
• Not just the Domain of the Ventilation Officer

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Hierarchy of Error
INADEQUATE VENTILATION KNOWLEDGE
POOR VENTILATION MANAGEMENT
POOR / INADEQUATE VENTILATION
LOSS HUMAN FINANCIAL
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Conclusion

• Ensure suitable knowledge base No.1 Priority
• Design and implement management plans that work.
• Note Good, effective management plans do not
  need reams of paper.
• Allow time and resources to implement plans.
• Train effectively regularly.
• Check that management plans work by regular
  auditing.
• Choose auditors wisely and allow time and
  resources for those people to be effective.
• EFFECTIVE MANAGEMENT PLANS WILL SAVE YOUR MINE
  MONEY