Dust
Introduction
By far the most important aspect of air quality in relation to quarries is the generation of dust. There may be small amounts of fumes or smoke generated from diesel equipment or processing plant which can cause a visual impact, but recent air quality controls have reduced these considerably. There may also be some gases such as NO2 and CO produced in the blasting process, and these are considered in more detail in the blasting section.
Dust generation is unfortunately an inevitable consequence of mineral extraction due to the processes of breaking and handling rock and soils. This would not be a problem if it stayed where it was created, but it often gets taken up into the air and transported around and outside the site (Photographs 1 and 2). Nuisance dust (sometimes referred to as deposited or fugitive dust) gives rise to the greatest number of complaints to quarries from local residents, and fears are commonly expressed in relation to the alleged health effects. Without appropriate mitigation, residents can potentially be affected by dust up to 1km from the source, although concerns about dust are most likely to be experienced near to dust sources, generally within 100 metres depending on site characteristics.
 |
 |
|
Photograph 1. Dust blowing off site on a windy day |
Photograph 2. Dust rising out of a deep hard rock quarry |
Although there are clearly defined methods of measuring and monitoring breathable dust, which have the potential to give rise to health issues, there are no such agreed systems for monitoring nuisance dust. There is a British Standard on the subject (BS 1747 170 172), but it is largely regarded as having limited value. Current UK government guidance on this issue (MPS2: Annex 1 –Dust L0259) simply states "A condition should usually specify that a scheme of monitoring be submitted for approval by the MPA (this will usually be developed as part of a dust assessment)". The variety of systems for monitoring breathable and nuisance dust will be described later.
Much of the information in this section is taken from Annex 1 of MPS2 L0259 (applicable in England only), which is itself is based on the Arup 1995 report "The Environmental Effects of Dust from Surface Mineral Workings" 76. Good practice for Scotland is given in the Scottish Executive's PAN 50 Annex B L0196.
Information has also been drawn from the comprehensive review of research associated with dust from mineral workings, which forms Parts 2 and 3 of the ALSF Review "Reducing the environmental effect of aggregate quarrying: dust, noise and vibration". L0089
At the time of writing (February 2011), a draft version was available of "Good Practice Guide: Control and Measurement of Dust and PM10 from the Extractive Industries" L0091. When this is published it will be a valuable document giving guidance on the use of Site Dust Management Plans to control dust emissions. A Review with detailed technical information will also be published.
Continued with Dust Definitions TOP Return to Introduction