Mine Ventilation
Risks & Controls
Jason Wagstaffe
Wagstaffe & Associates
1
VENTILATION HAZARDS
2
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
W&A
Wagstaffe & Associates
3
VENTILATION RISK
PREDICTION
4
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 mine’s 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.
W&A
Wagstaffe & Associates
5
VENTILATION RISKS
6
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.
W&A
Wagstaffe & Associates
7
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.
W&A
Wagstaffe & Associates
8
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.
W&A
Wagstaffe & Associates
9
VENTILATION RISK
CONTROL
10
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.
W&A
Wagstaffe & Associates
11
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.
W&A
Wagstaffe & Associates
12
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.
W&A
Wagstaffe & Associates
13
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.
W&A
Wagstaffe & Associates
14
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.
W&A
Wagstaffe & Associates
15
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.
W&A
Wagstaffe & Associates
16
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.
W&A
Wagstaffe & Associates
17
Risk Control (Cont)
VENTILATION CONTROLS
Include, but are not limited to:
Auxiliary Fans
Dust Extractors
Regulators
Overcasts
Permanent & Temporary Stoppings.
Venturi’s
Brattice
Booster Fans – Small & Large
W&A
Wagstaffe & Associates
18
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.
W&A
Wagstaffe & Associates
19
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
W&A
Wagstaffe & Associates
20
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 doesn’t need to appear in
the Management Plan itself.
Only work if people read and UNDERSTAND them.
Not just the Domain of the “Ventilation Officer”
W&A
Wagstaffe & Associates
21
Hierarchy of Error
INADEQUATE VENTILATION KNOWLEDGE
POOR VENTILATION MANAGEMENT
POOR / INADEQUATE VENTILATION
LOSS
W&A
Wagstaffe & Associates
HUMAN & FINANCIAL
22
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
W&A
Wagstaffe & Associates
23