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.
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.
