1.5 Planning and life cycle approach

In the subsequent chapters, airborne contaminants, dust, noise and vibration are each discussed in detail as separate issues within a common ‘life cycle’ approach covering exploration, design, evaluation, construction, operations, rehabilitation and closure.

1.5.1 Exploration

A range of airborne contaminant, noise and vibration issues are associated with exploration. The transient and often isolated nature of exploration creates an environment for potential clashes with local residents, unless operations are carefully monitored and considerable effort is made to keep the community informed of activities.

1.5.2 Design and approvals

The hazard identification, risk assessment and risk control planning discussed in Section 1.4 should be incorporated into the project design and communicated to stakeholders for comment and review. After the design and environmental impact assessment phases have been completed, a vast array of approvals for a wide range of commercial activities may be required. While the scope of this discussion precludes detailed analysis of the approval processes, it is sufficient to identify that considerable resources need to be devoted to identifying all the approval processes and ensuring that they are tracking effectively.

For small mines or quarries, such as those typically found in the opal fields or supplying sand and gravel, the hazards and risk management requirements in relation to air contaminants, noise and vibration are generally limited, as is the ability of the site operators to identify hazards and manage risk. The format

of materials to address these problems should focus on the development of simple checklists that address specific issues at the site. The site operators may need assistance to develop the checklists and identify appropriate responses when a significant issue is identified. Assistance from corporate centres, consultants or government officials should be sought as appropriate.

1.5.3 Monitoring plans

While all management systems need some form of planned monitoring, the strategy in developing the nature and frequency of data collection may be quite complex. Variables to consider include the nature of the hazard and the potential rate at which the risks in relation to the hazard may change. The cost of monitoring needs to be balanced by the potential cost of an adverse incident. Changes in monitoring technology need to be regularly reviewed as effective new systems emerge on a regular basis.

Monitoring for potential long-term impacts of occupational exposures (and the risk of such) is an area where new science and practice is slowly emerging. Interventions have traditionally been based on a level of harm, but there is increasing regulatory pressure to develop systems that trigger interventions based on elevated risk of harm.

1.5.4 Audit and review

While a health and safety or environmental management system may be leading practice at the time of its development, elements within the mine site or aspects relating to the community and technology may change. There is a need for regular audits of the system to ensure practices are being followed. At less regular intervals, comprehensive reviews are necessary to reassess the objectives and examine how the current system is meeting the objectives, and what modifications are necessary to improve performance.

1.5.5 Mine closure and rehabilitation

Mine closure is a process. It refers to the period of time when the operational stage of a mine is ending or has ended, and the final decommissioning and mine

rehabilitation is being undertaken. Closure may be only temporary, or may lead into a long-term program of care and maintenance. The overall objective is to prevent or minimise adverse long-term environmental, physical, social and economic impacts, and to create a stable landform suitable for some agreed subsequent use.

The long-term objectives of rehabilitation can vary from simply converting an area to a safe and stable condition, to restoring the pre-mining conditions as closely as possible to support the future sustainability of the site. Rehabilitation normally comprises:

  • developing designs for appropriate landforms for the mine site
  • creating landforms that will behave and evolve in a predictable manner, according to the design principles established
  • establishing appropriate sustainable ecosystems.

It is in the second process that the potential for dust and noise will become a problem. Creating sustainable landforms from spoil piles in strip (coal) mines, waste dumps in open-cut (metalliferous) mines, tailings disposal sites, and associated infrastructure such as roads, hard stand areas and the like will require extensive earthmoving. The earthworks will require large machinery and will usually result in dust and noise hazards that need to be controlled.

In most cases, the rehabilitation works will be carried out by contractors who may not have been involved in the mining process and may not be sensitised to the noise and dust management strategies employed when the mine was operating. It is important therefore that an appropriate induction program takes place to ensure contractors are aware of the potential hazards and can mitigate the risk arising from them.

Once the earthworks stage of the rehabilitation process has been completed, and all equipment has been removed from the mine, the noise hazard should be eliminated. However, a dust hazard may remain. A mine operator has ongoing responsibilities at the site until it is able to obtain a clearance certificate or relinquishment ‘sign off’ from the appropriate regulatory body. Governments are reluctant to absolve companies of their responsibilities, so they will be careful to ensure that there is low or no risk of dust emanating from the site.

If the site is affected by drought and the replanting program fails, the mine operator will need to carry out revegetation maintenance, particularly over waste dumps and tailings storage facilities. In high-wind areas it may be necessary to use additional surface capping, such as rock mulch, rather than rely on the success of the revegetation program. The impacts of fires on revegetation, potentially reducing rehabilitated surfaces to bare areas, should not be underestimated. This is particularly important in the Top End of Australia where the prevalence of fire in the dry season is widespread.

Further information on mine rehabilitation can be obtained from the leading practice Mine closure and completion and Mine rehabilitation handbooks (DITR 2008a, 2008b).

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