| Dealing with noise and vibration
Noise and vibration issues are stringently regulated and the operator must be in compliance with a number of key regulations and constraints, including:
Local guidance may also be in force that further reduces allowable noise and vibration. The regulation of quarry noise is the responsibility of council environmental health departments and therefore is usually enforced through the setting of planning conditions.
There are inherent problems in limiting noise from aggregate production sites due to the number of activities that take place in the open air. Ideally, noise issues should be fully assessed and considered at the planning stage of the site - it is at this stage that there is most scope for mitigating noise issues. Once the site is operational, it is much more difficult to reduce noise without significant cost implications (Goodquarry.com, 2005).
In general, the principal method that can be adopted by the operator to control significant or excessive noise is to reduce noise at source through simple changes to the design of the operation and operating practices for mobile and fixed plant. Options for reducing noise at source will vary according to the type and size of operation, the likely significance and frequency of the noise, and the surrounding areas, but general examples include:
When site noise cannot be readily managed at source, preventing noise leaving the site should be considered. This is most commonly achieved by using acoustic fencing or a mixture of topsoil, subsoil and overburden to create embankments around the site perimeter. Such approaches can typically halve the loudness of site noise for those outside its boundary. Other options to reduce noise leaving the site include:
- Designing a processing plant with a low noise output - prevention is normally easier than implementing noise reduction measures.
- Installing quieter plant or fitting silencers and implementing a regular maintenance or replacement schedule to prevent uncontrolled noise emissions from worn or damaged equipment, including mobile plant.
- Starting up equipment sequentially rather than all at once.
- Installing acoustic cladding around fixed plant areas (for example, the processing plant).
- Minimising the height that aggregate is dropped at transfer points and fitting insulation, such as rubber linings, to these points to avoid the noise of aggregate hitting metal surfaces.
- Localised screening of fixed items such as pumps and compressors.
- Replacing dump trucks with quieter conveyors.
- Enforcing speed limits and minimising steep haul roads to minimise dump truck engine noise.
- Minimising the use of vehicle reversing alarms by careful design of haulage routes that reduces the need for reversing near noise sensitive properties.
Using a mechanical ripper can reduce noise but is slower and more expensive than blasting.
- Locating the processing plant and other noisy fixed equipment away from noise sensitive areas.
- Restricting weekend and night working.
- Limiting of particularly noisy activities, including blasting, to times of the day when they are less likely to cause local disturbance.
- Limiting access by mobile plant to areas of the site in close proximity to noise sensitive locations.
|Limiting noise from aggregate production sites can be a problem due to the number of activities that take place in the open air. Early identification of potential issues is important as it allows mitigating measures to be built into the site design. If this opportunity is missed, once the site is operational, the costs of reducing noise can increase significantly.
The first step in dealing with vibration from blasting is to only use it where necessary and use alternatives (such as mechanical ripping) where possible, bearing in mind that these alternative methods will also be associated with environmental issues that need to be addressed. When blasting is necessary, the blast related vibration (and noise) could be reduced by a number of operational controls:
- Careful blast design and drilling of blast holes to ensure that the detonation of explosives is optimised.
- Blasting with a larger number of smaller explosive charges (rather than a smaller number of large charges), with suitable delays between detonations to reduce the cumulative impact of the blast.
- Determining the correct amount of explosive charge to avoid overcharging.
- Monitoring of ground vibration and air overpressure and use of results to further improve blasting design. This may include independent structural surveys of local housing to allay public concerns regarding the impact of vibration.
Goodquarry.com.For article Click here 2005. (last accessed on 25 Nov 2005).
Maslen, A. 2004. Environmental effects of quarry blasting. Chapter 6 in Environmental Management , The Institute of Quarrying, edited by M S Watkins and M R Smith, ISBN 0-9538003-4-2.
Walker, A. 2004. Environmental Noise. Chapter 7 in Environmental Management , The Institute of Quarrying, edited by M S Watkins and M R Smith, ISBN 0-9538003
Sources of further information
- GoodQuarry.com - Noise: Click here
- GoodQuarry.com - Blasting: Click here
- NECESI/The Environment Practice. 2004. Noise and Vibration. Chapter 2 (Section B-I) in Environmental Management Guidance Manual for SME Aggregates Companies . March 2004. Available from NECESI, University of Durham, Unit 1R, Mountjoy Research Centre, Stockton Road, Durham DH1 3SW.
- Mineral Planning Guidance Note 11 - The control of noise at surface mineral workings Click here
- Mineral Policy Statement 2: Controlling and mitigating the environmental effects of mineral extraction in England - superscedes Mineral Planning Guidance Note 11 Click here
- Additional useful information on vibration can be found in the Minerals Planning Guidance 9 (Annex A) and 14 (Annex M) Click here