Bell pit
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A bell pit is a primitive method of
mining Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the econom ...
coal Coal is a combustible black or brownish-black sedimentary rock, formed as rock strata called coal seams. Coal is mostly carbon with variable amounts of other elements, chiefly hydrogen, sulfur, oxygen, and nitrogen. Coal is formed when ...
,
iron ore Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the ...
, or other minerals lying near the surface.


Operation

A shaft is sunk to reach the mineral which is excavated by miners, transported to the surface by a winch, and removed by means of a bucket, much like a well. The bottom of the shaft is enlarged and a sloping roof is created as the desired mineral and surrounding rock is removed – giving its name because the pit in cross section resembles a bell. Typically, no supports were used, and mining continued outwards until the cavity became too dangerous or collapsed at which point another mine was started, often in close proximity. Example and illustrated description This type of mine was in use in prehistoric times, the Middle Ages, and a few continued in use until the early 20th century in the region around Ford, Northumberland. Such pits are common at prehistoric flint working sites such as Grime's Graves in
Norfolk Norfolk () is a ceremonial and non-metropolitan county in East Anglia in England. It borders Lincolnshire to the north-west, Cambridgeshire to the west and south-west, and Suffolk to the south. Its northern and eastern boundaries are the Nor ...
and also in the coal mining areas of Yorkshire, the
Forest of Dean The Forest of Dean is a geographical, historical and cultural region in the western part of the county of Gloucestershire, England. It forms a roughly triangular plateau bounded by the River Wye to the west and northwest, Herefordshire to ...
, and Leicestershire. Bell pits often flooded due to a lack of a drainage system. This, together with the lack of support and the likelihood of collapse, meant they had a limited lifespan. The remains of bell pits can be identified by depressions left when they collapsed. In some places, they will follow a straight line as the seam of mineral is being followed. Bell pits were not an efficient way of extracting minerals as they only partially exploited the resources.


See also

* Drift mining *
Open-pit mining Open-pit mining, also known as open-cast or open-cut mining and in larger contexts mega-mining, is a surface mining technique of extracting rock or minerals from the earth from an open-air pit, sometimes known as a borrow. This form of mini ...
* Industry and the Eglinton Castle estate *
Glossary of coal mining terminology This is a partial glossary of coal mining terminology commonly used in the coalfields of the United Kingdom. Some words were in use throughout the coalfields, some are historic and some are local to the different British coalfields. A Adit :A ...


References

Coal mining Underground mining {{civil-engineering-stub