Noise from Alcoa’s mining operations is recognised as a potential impact on neighbours living close to the mines and is therefore a priority area of environmental management.
Primary sources of noise from the mines include:
- Blasting of the hard caprock ore layer;
- Mobile equipment such as dozers, scrapers, trucks and excavators; and
- Fixed plant equipment such as conveyor belts, transfer stations and crushers.
Noise is regulated by the Department of Environment and Conservation (DEC). The Environmental Protection (Noise) Regulations 1997 were implemented in 1999 and apply to the Huntly and Willowdale Mines. The noise regulations for operational noise set limits for day time, evening and night time periods. For example, the set noise limits for Day, Evening and Night are 45dB(A), 40dB(A) and 35dB(A) respectively. For blast noise, no blasts are to exceed 125 dB(Lin Pk) and 9 out of 10 blasts are not to exceed 120 dB(Lin Pk).
WA Mining has noise management plans in place to ensure compliance with the Environmental Protection (Noise) Regulations 1997 and minimise noise impacts on neighbours.
Mobile Equipment Noise
At Alcoa’s mines, predictive computer modelling and monitoring have assessed the potential noise impacts of mobile equipment. Accordingly, Alcoa has developed and implemented a comprehensive noise management program which includes monitoring systems, procedures, training and audits to ensure effective day to day management of equipment and response to community concerns.
The extensive noise modelling and monitoring undertaken has verified that Huntly and Willowdale Mines are compliant with the Environmental Protection (Noise) Regulations 1997. Similar modelling is also conducted when developing a noise management strategy for new mining regions. This strategy enables us to determine a particular combination of equipment for a specific pit under certain weather conditions.
Management of noise at Willowdale Mine is of particular importance due to close proximity of neighbours, predominantly along the western boundary. Mining activities at Willowdale are restricted to specific areas at night to avoid nuisance to neighbours and a continuous noise monitoring network has been established on neighbours’ properties. Alcoa also has an automated weather station that provides real-time wind speed and direction information.
The data from the noise monitors and weather station are used to proactively manage operations to minimise noise impacts on neighbours.
In preparation for a blast, a predictive computer model is run to assess if conditions will ensure the blast meets the required noise limits. This model incorporates the mine pit location, current weather and atmospheric conditions and the location of neighbours in the direction of the predicted impacts.
Alcoa applies internal blast noise limits, which are stricter than the Government regulatory standards. Each blast is monitored at neighbouring properties, predicted to be most impacted by the blast noise, to check levels from a ‘pilot shot’ and to confirm compliance during the main blast.
Fixed Plant Noise
A series of controls has been implemented to reduce noise from conveyors and associated infrastructure. For example, at Willowdale barrier fencing has been installed along side sections of the conveyor, the conveyor belt has been enclosed, quieter conveyor rollers have been installed and cooling fans have been replaced with heat exchangers. In addition, a program for conveyor belt washing has been implemented to reduce dirt build up and reduce noise.
Ongoing maintenance and noise monitoring ensure noise levels remain at acceptable levels.
A Mining Noise Lead Team was established in 2001 and meets on a regular basis to progress noise reduction strategies. Some of the improvements and trials undertaken to date include:
- Installation of alternative reversing beepers on mobile equipment;
- Fitting acoustic enclosures to the new truck fleet;
- Trialling excavator bucket modifications to reduce scraping noise;
- Trialling noise cancellation technology developed by universities;
- Appointment of Mine Neighbour Relations Officers to establish, develop and maintain close communications with all neighbours who may be impacted on by our operations.
- Blast noise reduction trials including investigation of alternative rock breaking methods.
- Benchmarking noise management and monitoring systems (including weather monitoring systems) used by other mining companies in the New South Wales Hunter Valley.
The Mining Noise Lead Team continues to meet regularly to investigate and implement operational and blast noise reduction strategies and drive continuous improvement activities.
Noise Management Fact Sheet
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