The quarry boundary is defined as the edge of the planning
permission within which a working quarry operates. No excavation
or earthworks are allowed outside of this boundary, unless
an additional planning permission is granted.
The actual extent of the excavation within the quarry boundary
will depend on a number of factors:
- The extraction limits set out in the planning permission.
- The requirement to ensure safe and stable slopes, both
within the excavation and for any artificial screening
- The extent and quality of the required mineral. There
is no point in a quarry operator excavating right up to
the quarry boundary if the required mineral is not present
- The cost of working the mineral compared to its value.
If, in one area, the costs of extraction are too expensive,
or the quality of the mineral is too poor, it may not be
economic to recover the mineral there.
- The intended future use of the site after restoration.
- The requirements to minimise adverse environmental impacts,
including the visual appearance of the site, dust, noise,
- The requirements to promote environmental benefits, for
example habitat creation.
if there are buildings near to a working quarry the operator
will be required to leave an area unworked as a buffer zone
(also known as an 'Environmentally acceptable standoff') between
the quarry and the buildings. This buffer zone may fall inside
the quarry boundary and will reduce the volume of mineral that
can be worked. If a quarry is visible from outside the quarry
boundary the operator may be required to build screening
banks banks (also known as amenity banks) or to plant trees
to improve the appearance of the site. These will fall within
the quarry boundary and, because they take up space, they will
reduce the volume of mineral that can be worked.
Safety is very important
in all working quarries, and sometimes the extent of excavation
is limited by the need to ensure slope
within the boundary of a roadstone quarry in Devon.