Limestone is, without doubt the world's most useful rock and
we are fortunate that there is plenty of it around the UK.
We use limestone in three main ways:
- as a building and ornamental stone
- to make concrete
- for the different layers in our roads
- to make cement and iron
- to remove the sulphur from power station gases
- to add calcium to animal feeds
- to neutralise acids in wine and beer making
- to make lime for a variety of industrial and agricultural
There are over 2000 quarries and associated manufacturing sites in the UK.
They are of two main types:
quarries are usually much deeper and are dug on several different
levels or "benches". The first stage is usually a carefully
controlled explosion that releases and breaks up the rock into
large lumps. A large truck or conveyor then takes it to a powerful
crusher where it is broken down into fragments and separated into
Sand and gravel quarries are rather shallower because the deposits
are usually only five or six metres thick. The material is dug
with a mechanical shovel or a dragline and is then carried by
conveyor to a plant where it is washed and separated into different
In both cases, the aggregates are then delivered to customers by lorry, by rail and by sea. Rail transport is
used where the aggregates need to be carried over longer distances
such as from the Mendips or the Midlands into London.
are also used in lots of less obvious ways.
- Ground chalk is added to bread to give us calcium
- Salt is added to our food during cooking
- Pills consist of a small quantity of drug absorbed onto a
"carrier" such as white clay
- The abrasive in your toothpaste comes from limestone
- Clay is used in face creams
Aggregate is the term we use for rock that has been broken into
small pieces, either by nature or by people. Demand for aggregates (both primary and recycled), which peaked at some 330 million tonnes a year in 1989, has fallen to around 200 million tonnes due to the recession. Aggregates are mainly used for building.
are of two main types of crushed rock, sand and gravel. If you
draw a line across the UK between Humberside and Dorset you will
find plentiful sand and gravel deposits to the south of that line
and hard rocks to the north. Sand and gravel is rock which nature
has already broken into fragments, mostly by weathering and by
erosion during the ice age.
But not all aggregates are taken from the land. About 21 per
cent of the sand and gravel needs of England and Wales are supplied
from the sea. Most of this comes from licensed areas in the North
Sea and off the South Coast. Smaller licensed areas exist in the
Bristol Channel and in Liverpool Bay.
For more information about rocks as aggregate click
is a temporary rather than permanent use of the land. Sand and
gravel quarries may last no longer than 15 years and the land
that has been dug is restored in stages. This may involve returning
the land to farming with no obvious sign that it has ever been
quarried. But it might instead provide an opportunity to create
a nature reserve or sports pitches.
Because they are much deeper, rock quarries take much longer
to restore but they too may be given back to farming or used to
create nature areas. There are lots of examples of sites that
have been quarried and are now more exciting and interesting as
For more information about restoring the land visit the sustainability microsite here.