South Lancashire Coalfield

The Lancashire Coalfield in North West England was one of the most important British coalfields. Its coal seams were formed from the vegetation of tropical swampy forests in the Carboniferous period over 300 million years ago.

The Romans may have been the first to use coal in Lancashire and its shallow seams and outcrops were exploited on a small scale from the Middle Ages and extensively after the start of the Industrial Revolution. The coalfield was at the forefront of innovation in coal mining, prompting the country's first canals, use of steam engines and creating conditions favourable for rapid industrialisation.

The pits on the coalfield were at their most productive in 1907 when more than 26 million tons of coal were produced. By 1967 just 21 collieries remained. Parkside Colliery in Newton-le-Willows, the last deep mine to be sunk on the coalfield, was closed in 1993.

The geology of the coalfield consists of the coal seams of the Upper, Middle and Lower Coal Measures, layers of sandstones, shales and coal of varying thickness, which were laid down in the Carboniferous period over 300 million years ago. The coal seams were formed from the vegetation of tropical swampy forests. The coal in Lancashire is bituminous with 30–40% volatile matter varying in hardness from seam to seam.

The coal measures were subsequently subjected to folding accounting for the dip towards the south and west and faulting occurred at this time. The Coal Measures are over 4000 feet thick and coal accounts for approximately 4% of their thickness. The coalfield is crossed by several major faults which generally run in a north and south direction. The most significant easterly fault described by Edward Hull throws the strata down to the east. It was worked from Fairbottom in Ashton-under-Lyne across the River Medlock to Oldham and onwards to the west of Rochdale. The Red Rock Fault skirts the north-west extremity of the North Staffordshire coalfield towards Macclesfield and Poynton Colliery in Cheshire. The Irwell Valley or Pendleton Fault passes Clifton and Kearsley where it throws the coal measures down to the north-east. It has a throw of 3000 feet and the area is still geologically active and subject to earth tremors. A fault with a large horizontal but small vertical throw is found at Tyldesley. In the deep mines at the southern edge of the coalfield, the Plodder mine in Leigh and the Arley mine in Tyldesley were hot; the miners worked in temperatures of over 100 degrees Fahrenheit.

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