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Pleasley Pit Visitor Centre

Stage 2

Pleasley Pit Visitor Centre

The story of coal formation and the coal mining process

Coal consists mainly of carbon. Diamonds are 100 per cent carbon. Therefore, a phrase coined many years ago referred to coal as being ‘black diamonds!’

Coal, mined at Selby Colliery in 1983 – the same year Pleasley Pit closed. Picture Source: Paul Fillingham.

In Britain, the formation of coal goes back anything from 170 to over 300 million years ago in a tropical or sub-tropical climate. Coal originated from vegetable matter in vast swamps, this era being known as the Carboniferous period. Huge forests grew up and died, the land sank and flooded once more. The vegetable matter formed peat, which was covered in sediment and underwent a series of compaction over millions of years to eventually form coal.

Video: Pleasley Pit fossil collection.

Sometimes a coalminer would find an imprint of a leaf or some wood bark in the coal or adjoining rock. These are fossils. In the 1970’s at nearby Bolsover Colliery, the fossil of a large prehistoric dragonfly was discovered in the coal workings.

Carboniferous forest. 

Sometimes a coalminer would find an imprint of a leaf or some wood bark in the coal or adjoining rock. These are fossils. In the 1970’s at nearby Bolsover Colliery, the fossil of a large prehistoric dragonfly was discovered in the coal workings.

Geological cross section from Riddings in Derbyshire to Annesley in Nottinghamshire showing the main coal seams.

The Exposed and Concealed coalfield

The coal formed into seams lying between other mineral and rock deposits at various depths. Some coal seams lay nearer to the surface and others were much deeper. The shallower seams in the Derbyshire coalfield were to the west of a line between Nottingham and Chesterfield and this was known as the exposed coalfield. Locally it is referred to as the outcrop. The seams then dip gradually towards the east through Nottinghamshire becoming deeper. This was known as the concealed coalfield.

Map showing the main coalfields of Britain. 

The coal seams had different names and some of these mined at Pleasley include the Top Hard, Waterloo, Dunsil and Deep Hard. Coal seams are sometimes named after places where they were first mined.

Pleasley Colliery was part of the large central, Yorkshire, North Derbyshire and Nottinghamshire coalfield. It was this coalfield, where deep coalmining in Britain finished in 2015.

The Industrial Revolution at Coalbrookdale in Shropshire, known as the Cradle of the Industrial Revolution.

Uses of coal

Initially, in medieval times, coalmining was small scale and was mainly used for domestic heating in houses. The advent of the industrial revolution in Britain from the mid to late 18th century saw demand for coal increase dramatically. This was linked to the development of the steam engine, which powered industry and transport into the second half of the 20th century.

Markets for British coal in the 1950’s.

Ratcliffe on Soar coal-fired power station in the 1980’s. Picture Source: Alf Henshaw collection.

From the 1960’s through to coal’s decline in the Britain in the 1990’s, it was used mainly to generate electricity. Coal went by train from the collieries to coal fired power stations and came back to the factories, warehouses and homes via high voltage transmission lines on pylons – coal by wire!

A domestic coal house. Picture Source: David Amos.

Different types of coal

There are many different types of coal, all for different uses. In the past large lump coal was used for domestic heating in houses, in the days before central heating. Houses in the past sometimes had coal fires in a number of rooms. The man who delivered the coal was called the Coalman.

The coalman delivering domestic coal. Picture Source: The Coal Authority.

Coal fire in the living room of a pit house in Annesley Rows, 1980. Picture Source: David Amos. 

Video: Different types of coal were extracted from various seams at Pleasley Pit.

Electricity supply coal known as blended smalls, a type of slack, which was pulverized when it got to the power station. Coke was the first man-made smokeless fuel and was first used in iron smelting, and many other industrial applications, including the manufacture of town gas.

Next

Let’s move on to one of Pleasley Pit’s preserved headstocks, and see what part it played in the story of coal.