Safe working environment for mines

Who may enter the mine

Under regulation 408 of the OHS Regulations, mine operators must ensure that:

• no persons enter the mine without permission - other than an inspector or authorised representative of a registered employee organisation
• no person under the age of 16 works at any open cut workings or underground mine
• no person under the age of 18 works at an underground mine unless they are an apprentice or trainee over the age of 16 and directly supervised

How to control entry to the mine

It is important that only authorized persons enter a mine. Anyone entering the mine must have their identify verified and undertake mine inductions/relevant training before entering the mine.

Mine operators may control entry to the mine:

• using appropriate fencing and security systems to keep out unauthorized persons
• by sighting hard copies of employee’s birth certificates, driving licenses, or passports to verify authorized persons
• by ensuring mine inductions have been completed by persons before they enter the mine

Apprentices and trainees at the mine

Pursuant to regulation 408 of the OHS Regulations, you must ensure apprentices and trainees working at the mine are:

• adequately instructed on how to do a task safely and provided demonstrations
• assigned tasks that match their competency
• directly supervised until such time as their supervisor believes it is no longer necessary as their level of competence is sufficient and a lesser degree of supervision will not place the apprentice or trainee, or any other person, at risk

Essential lines of communication

This refers to Regulation 415 and 416, which are duties for operators of any mine.

Isolated employees working alone

When an employee is working alone at an isolated location at a mine, you must ensure the employee has the means to be able to communicate effectively.

Examples of how you can do this include:

• two way radios that work effectively without satellite dependency, for example: communication systems that use 'Leaky Feeder'
• telephone systems
• mechanical shaft knocker systems used in shafts

You must ensure there is a system of communication by which:

• outgoing supervisors document the state of mine workings, plant and any health and safety matters, and effectively communicate its contents to incoming supervisors – for example: the documented information should be exchanged during shift handovers
• incoming supervisors communicate the contents of the report to incoming employees

Examples of information typically recorded include:

• location and status of mining hazards
• condition of mine workings (e.g. geotechnical matters, dewatering status, road conditions, ventilation issues)
• location and status of plant and machinery
• condition and status of mine’s production and development cycles
• recent changes and/or status emergency management infrastructure or process (e.g. location of mine refuge chambers and/or escape ways)

Shafts and winding

Pursuant to regulation 425 of the OHS Regulations, operators of a prescribed mine must ensure every shaft winding system includes:

• ropes able to bear the weight of shaft conveyances and additional loading, which are tested regularly
• adequate controls to prevent shaft conveyances from being overwound or overrun, or from travelling at unsafe speeds
• devices that detect slack rope or drum slip conditions, or tail rope malfunctions, and devices that cause the winder to stop when such conditions or malfunctions are encountered
• appropriate communication systems to and from all entrances to the winder room
• protection for persons being conveyed, especially where materials are conveyed in the same shaft
• a system to ensure materials are not carried in a skip while persons are carried in a cage (where a shaft conveyance is used as a combined cage and skip)
• adequate energy lockout devices are fitted to all mechanical and electrical plant
• a mechanism to ensure materials and plant are:
  • not protruding
  • safely secured
• the ability for automatic winding systems to be monitored from outside the winder house
• the ability for automatic winding systems to included adequate warning systems in any emergency in the shaft
• in relation to automatic winding systems - open lines of communication between the surface and persons being conveyed is provided and maintained
• loading facilities designed in such a way as to prevent spillage into the shaft

How to ensure safe shafts and winding systems

Further to Regulation 425, winder drivers (i.e. winder operators) and employees who use shaft winding systems must be informed, instructed and competently trained in systems and processes for the safe operation of winder systems. Refer to Regulations 439 – 441 for additional information.

WorkSafe Victoria provide advice and guidance to assist operators in ensuring winder drivers are trained and competent in accordance with training programs developed against nationally recognised standards. Mine operators should make contact with WorkSafe's Earth Resources Program for further assistance. Email [email protected].

Materials used for filling

Under regulation 428 of the OHS Regulations, mine operators must ensure that the material used to fill mined out areas does not pose risks to health and safety of any person.

Safe filling practices

Before commencing filling practices (generally referred to as Back Filling), mine operators must consider the safe reticulation and placement of fill. This may include the transportation of fill via pipelines or mobile plant, and its structural integrity once placed within underground voids. Consideration should be given to:

• fill stability (e.g. potential to fail if exposed or mine against)
• the likelihood of placed fill to liquefy (i.e. escape from place areas and cause a potential inrush)
• the adequacy of barricades/engineering structures used to contain the fill mass
• the adequacy of reticulation infrastructure (e.g. pipeline design and associated loading)

Working environment at the mine

Under regulation 429 of the OHS Regulations, operators of a prescribed mine must ensure:

• the air at areas of the mine where a person does or may work or travel is maintained at a safe level, which means the air:
  • contains a safe oxygen level
  • does not contain harmful levels of contaminants or impurities
• controls are in place to prevent thermal stress
• moisture content is at a level at which work can be performed safely
• lighting is sufficient to enable work to be performed safely.

Atmospheric standards

Atmospheric contaminants and minimum oxygen levels within underground work environments must be maintained in accordance with work place exposure standards set by Safe Work Australia.

Consideration must be given to the Time Weighted Average (TWA) levels referenced within Safe Work Australia's standard and guidance. These levels have been calculated using an average 8 hour working shift per day per employee. Generally, mine employees work longer hours per shift and therefore exposure levels need to be recalculated accordingly.

Heat and humidity have a considerable influence on underground employees by introducing thermal stress. Mine operators should ensure air velocity, temperature (wet and dry bulb) and humidity levels are monitored; and the results compared against recognised guidelines to ensure employees are not exposed to unsafe levels of heat stress. Guidance adopted within industry provides direction on the type of work that can be carried out for specified lengths of time, whilst referencing the measured environmental conditions.

Ventilation at the mine

This refers to Regulation 430 and 431, which are duties for operators of a prescribed mine.

You must ensure:

• airflows do not recirculate within ventilation circuits
• airflow regulators are adequately maintained
• air is fit to breathe because it does not pass through too many work areas
• dead-end openings are only worked if adequate auxiliary ventilation is provided
• underground workings are not ventilated with contaminated air

All aspects of the ventilation system must be regularly monitored and tested. You must also maintain a record of the system’s monitoring and testing, which can be read and understood by all who use it. This record must be kept and made available at the mine.

How to create safe ventilation systems

Mine operators should consider eliminating or reducing the re-use of mine air throughout the mine’s ventilation network. It is considered good practice to assess this potential during initial mine design activities.

Each operating area of a mine, when combined with diesel equipment use, produces atmospheric contaminants (e.g. carbon monoxide, carbon dioxide and diesel particulates) and heat, whilst consuming available oxygen. When the air cascades to subsequent mine areas contaminant and heat levels incrementally increase, therefore potentially exposing employees to unsafe atmospheres.

To provide the optimal air quality at working areas, mine operators should:

• maintain ventilation doors and bulkheads used to prevent air short-circuiting
• maintain ventilation duct to minimise leakage and maximise air flow quantities at working areas
• design ventilation networks to minimise air re-use throughout the mine
• maintain ventilation fans to ensure they are fully functional
• readily monitor, record and assess air flow and contaminant levels in the mine
• communicate air monitoring results with employees