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Quarry Design
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Quarry design
The designs for quarries, and the plans for their
restoration, are as varied as the number of locations
where quarrying takes place. However, some basic
principles apply to all quarries to ensure safe and
efficient sites during extraction, restoration and
subsequent use.
Quarries operate within a strict planning system and
the issues of safety, visual appearance,
environmental protection and the future use of the
site will be investigated and incorporated into the
quarry design before a planning application is
submitted.
An artist impression of a quarry re-development.
Quarry operators have to carry out an
Environmental Impact Assessment as part
of this planning process, and develop a
sustainable plan for the closure and
restoration of the site. The quarry design
will incorporate the quarry layout,
extraction methods and operating
procedures. In particular, it will establish:
the quarry boundaries, and the
extent of the extraction within those
boundaries;
the required procedures to ensure
the safety of all people within or
around the site, including the
methods that will be used to
stabilise slopes and protect against
rockfall;
the position of any slopes and
banks during extraction and those
that will remain as part of the
restoration;
the method of accessing all part of
the site and the location of access
ramps, both during and after
extraction.
The quarry design will also include a
detailed plan for restoration and subsequent
after use, environmental management
procedures, a method of working, details of
infrastructure such as roads and buildings,
and the requirements for processing
equipment.
Quarry boundary
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 banks.
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
there.
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, etc.
The requirements to promote
environmental benefits, for
example habitat creation.
Often 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 stability.
Planting within the boundary of a roadstone quarry
in Devon.
Safety and stability
One of the primary responsibilities for the
quarry operator is to ensure the safety of
all employees, contractors, visitors and
members of the public, whether they are
within the quarry boundary or any other
area affected by the workings of the
quarry.
This includes responsibility for:
The stability of any slope whether this is the quarry face,
screening banks , stockpiles of
finished product or waste tips.
Safe access to all parts of the
quarry where people need to go.
And also:
Traffic management within the
quarry boundary
Safety around processing
machinery
Assessment of risks
Occupational health
Safety procedures and daily
inspections
All operations in quarries are governed by the
Quarry Regulations 1999.
Slopes and banks
There are various different kinds of slopes
within a quarry and one of the primary
concerns of the quarry operator is the stability
of these slopes. They include the rock cliffs of
the quarry face , but also screening banks ,
stockpiles of finished materials, waste tips and
material used in restoration.
Quarry faces will be worked in a series of
layers known as benches . These comprise
sections of horizontal ground between
successive quarry faces, each face being
usually no more than 15 metres in height.
These levels represent previous quarry floors
in earlier parts of the quarry life. Working in
benches ensures no quarry face forms an
excessive height in a single cliff for safety
reasons.
In some cases access needs to be maintained to
these slopes and benches for restoration work,
maintenance, or for the study of geological
features.
Low benching of rock to provide for long-term
safe access to a geological SSSI.
Natural woodland on the left has been copied in the bench planting to the right.
Access and open areas
Open areas within a working quarry
include the benches and quarry floor.
Access to them during working operations
is obtained by access ramps and haul roads.
However, access is still required after
extraction has ceased to enable restoration
to be completed and for whichever after
use has been planned. Access may also be
required for the purposes of maintaining
rock faces for safety reasons and for the
study of any interesting geological
features.
As with any open area drainage is an
important consideration for the quarry
floor, and quarry benches, because it will
have an affect on the after use for the land,
where it could impact on the foundations of
any buildings. In addition the flow of water
causes erosion and may undermine the
stability of quarry faces.
Access road with bench restoration behind.