Rock quarries usually operate for at least 30 years and are developed
in distinct 'benches' or steps. A controlled explosion is normally
used to release the rock from the working face. It is then transported
by truck or conveyor to a crusher to go through a series of crushing
and screening stages to produce a range of final sizes to suit
Sand and gravel quarries are much shallower than rock quarries
and are usually worked and restored in progressive phases. This
means the area exposed for quarrying at any time can be minimised
and land that has been 'borrowed' is out of productive use for
a limited period.
A significant proportion of Britain's need for aggregates is
satisfied from the seabed.
At a time when land-based quarrying is under increasing environmental
pressure, our vital marine resources are growing in importance as another
way to sustain the built environment. What's more, marine aggregates
take a front line role in replenishing Britain's beaches and protecting
our coastline from erosion.