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.