Somerset coalfield
The Somerset Coalfield in northern Somerset, England is an area where coal was mined from the 15th century until 1973. It is part of a larger coalfield which stretched into southern Gloucestershire. The Somerset coalfield stretched from Cromhall in the north to the Mendip Hills in the south, and from Bath in the east to Nailsea in the west, a total area of about 240 square miles (622 km2). Most of the pits on the coalfield were concentrated in the Cam Brook, Wellow Brook and Nettlebridge Valleys and around and Farrington Gurney. The pits were grouped geographically, with clusters of pits close together working the same coal seams often under the same ownership. Many pits shared the trackways and tramways which connected them to the Somerset Coal Canal or railways for distribution.
The early pits were adits where coal outcropped or bell pits where coal was close to the surface. These methods were abandoned when deep seams were mined. The deepest shaft on the coalfield was at the Strap mine at Nettlebridge which reached 1,838 feet (560 m). Flooding and coal dust explosions in some mines required improved ventilation and pumping engines. Several pits closed in the 19th century as the coal was worked out. Those that survived until 1947 became part of the National Coal Board, but the expense of improving equipment and working conditions meant that these became uneconomical and the last pit closed in 1973. There is still evidence of the mine workings, with the remains of buildings, spoil heaps and tramways in the area.
The Somerset Coalfield covers a total area of about 240 square miles (622 km2). It consists of three synclines, informally referred to as 'coal basins'. The Pensford Syncline in the north and the Syncline in the south are separated by the east-west trending Farmborough Fault Belt. Further to the west is the smaller Nailsea Syncline. The Radstock Syncline in particular is cut by a series of east-west thrust faults and north-south trending normal faults.
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