Extraction

With one exception in Western Scotland where it is extracted by underground mining, silica sand is extracted by surface quarrying. This is both by wet and dry working and the workings can very in depth from less than 2 metres to over 30 metres. Loosely consolidated sands are normally extracted using a face shovel after the soils and overburden has been carefully stripped and stored for use in the future restoration of the quarry. Hard sandstone deposits are normally ripped to break them up before being taking for processing The stored soils and overburden can be used to create temporary landscaped banks to screen the extraction operations. The sand is usually taken back to a centrally located processing plant by conveyor or dump trucks depending on the configuration of the site and scale of operations. Dry workings are normally progressively restored at lower levels back to the previous agricultural or forestry use. This is often accompanied with the establishment of an increased diversity of wildlife habitats.

When there is a high water table the sand may be extracted by suction dredger and it can then be pumped back to the processing plant in slurry form by pipeline. Wet workings will normally be restored to landscaped lakes, though they can be backfilled with inert fill materials. The lakes will then be used for wild life conservation or were appropriate for recreational purposes.

Silica sand is a naturally occurring material and normally different grades will be found in each deposit. This may necessitate working in separate areas within a quarry to produce different products or to permit the blending of the material to produce a more homogenous material. In some cases there may be a series of satellite quarries feeding a centralyy located process plant with the required mix.

At Lochaline in western Scotland the silica sand is extracted by underground mining methods. This is unique in Britain and is only viable due to the exceptionally high quality of the deposit.