Mine Ventilation Risks

8/10/2019 Mine Ventilation Risks

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Mine VentilationRisks & Controls

Jason Wagstaffe

Wagstaffe & Associates


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VENTILATION HAZARDS


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Ventilation HazardsSources 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 &AW a g st a f f e & Asso c i a t es


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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 minesventilation 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 dustRespirable / Inhalable & Dangerous Float Dust.

Diesel particulateRespirable & 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 applicablelarge gas reservoirs)

Gas rgime / reservoir modeling

Have systems in place that can deal with large quantities of gas if it isrequired.

Management Planwith 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.

Spraysmachine mounted and fixed systems

Wet drilling

Too much air velocity can create dust issues.

Pre-drained coal may require water injection to assist with dustsuppression.

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 ordamage 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 foroperators 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

Highstandard 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 FansSmall & 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 forSpontaneous 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 MorebyAssociate 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 1003Windblast Code of PracticeMDG 1006Spontaneous 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 inthe 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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ConclusionEnsure suitable knowledge baseNo.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 thosepeople to be effective.

EFFECTIVE MANAGEMENT PLANS WILL SAVE YOUR MINE MONEY


Documents

Mine Ventilation Risks