Silica sand is an essential raw material for many industrial processes including the manufacture of glass, production of foundry castings and ceramics. It is geologically and geographically sparsely distributed and, consequently, the mineral is a valuable resource of recognised national importance. Silica sand is quarried between Bletchingley and Godstone under permissions granted by the Mineral Planning Authority, Surrey County Council.
As a result of planning applications in the Bletchingley/Godstone area, concerns about health risks and nuisance dusts have been raised with the District Council.
According to the Health & Safety Executive, silicosis is a disease that has only been seen in workers from industries where there is a significant exposure to silica dust, such as in quarries, foundries, the potteries etc. No cases of silicosis have been documented among members of the general public in Great Britain, indicating that environmental exposures to silica dust are not sufficiently high to cause this occupational disease.
Fine particles PM10
PM10's are particles with a diameter of less than 10μm. The principal sources of these are vehicle exhaust emissions, sea salt, pollen, aerosols, chemicals and dusts. Some of these fine particles are a health concern because they can be inhaled directly into the lungs and over long periods of time may be associated with respiratory ailments.
According to the British Geological Survey mineral planning factsheet, the particles sizes of quarried silica sand in the United Kingdom are generally in the range 100μm to 500μm. The quarry is not, therefore, likely to be a significant source of PM10.
Dust particles are dispersed by their suspension and entrainment in an airflow. Dispersal is affected by the size of the particles emitted, and wind speed as well as their shape and density. Large dust particles (greater than 30 μm), which make up the greatest proportion of dust emitted from mineral workings, will largely deposit within 100m of sources. Intermediate sized particles (10-30 μm) are likely to travel up to 200-500m. Large and intermediate sized particles are often referred to as nuisance dust.
Dust concentrations decrease rapidly on moving away from the source, due to dispersion and dilution.
The only unobstructed view of the quarry's plant area is from the site entrance.
View of the Quarry from site entrance on the Eastern Boundary
View of the Quarry from the Western Boundary
Complaints about dust on cars and window sills etc a 1000m or more from a quarry could be due to other sources, such as general background dusts, from agricultural activities , tree pollen or dusts that have been carried over long distances in the upper atmosphere, for example, desert sands, which are much finer and lighter than locally quarried sand.
According the the Meteorological Office, desert sands from the Sahara are frequently seen in the United Kingdom in the Spring, though they occur at other times as well. These dusts tend to be washed out of the air by rainfall and can be seen on cars, window sills and other flat surfaces.
Desert dust distribution in the atmosphere over Europe in May 2008
Allegations of nuisance can only be pursued by someone with an interest in land with evidence that the action complained of is directly affecting the comfort and enjoyment of their land. In order to support the allegations, evidence is required of the frequency, duration and severity of the events and the complainant should be prepared to provide this in the form of a diary/log sheets.
Casual users of the bridleway along the quarry boundary cannot suffer a nuisance even if they may be affected by airborne sand. Bridleway users will be aware that the Quarry's excavations and buildings cannot be seen from the bridleway, it is separated from the Quarry by open space, landscaping and a substantial hedge, and is itself on a bed of sand that could be a source of airborne sand.
View of the bridleway/track along the southern boundary of the Quarry
Commercial companies are obliged to do everything that is reasonably practicable to prevent nuisances. The law does, however, recognise that even if all reasonable steps are taken, there may be times when the activities will affect occupiers of land outside the site boundary, for example, when there are unusual weather conditions.
The Quarry operates under permissions and conditions granted by Surrey County Council aimed at controlling dust emissions from the site and minimising potential nuisances in accordance with Government Guidance. Local residents alleging that the planning conditions are not being complied with should contact Surrey County Council with the details.