“At almost every single part of the extractive and downstream processing stages of a quarry operation some level of noise may be generated. The extractive sequences of overburden removal and storage, drilling and blasting, loading and transportation (by dump trucks or conveyor belts) of the quarried minerals to the processing plant will all generate both mobile and static noise sources. The normally static processing plant consisting of the primary crushing and secondary processing of the mineral products will also present a source of noise.
Large scale extractive and processing operations can only be economical with the use of high powered diesel earth moving machinery (such as drills, bulldozers, dumpers, shovels etc) and explosives, which will create a potentially high level noise that may be transmitted to the immediate surroundings causing nuisance to near residents. … It has recently been reported that the noise levels encountered from many quarries or surface coal mines are second only to that encountered near to jet engines at airports.”
This is extracted from an informative report prepared in 2008 for the UK Mineral Industry Research Organisation by academics at the Universities of Nottingham and Leeds commenting on noises and dust from quarrying: Reducing the Environmental Effect of Aggregate Quarrying.
In the light of this statement it is essential that evidence is available (perhaps from existing gravel quarries) of the noise level that can be expected at different times of the day and night at distances of say one, two and four kilometres from quarry workings.