Oldham Coalfield

The Oldham Coalfield is the most easterly part of the South Lancashire Coalfield. Its coal seams were laid down in the Carboniferous period and some easily accessible seams were worked on a small scale from the Middle Ages and extensively from the beginning of the Industrial Revolution in the early 19th century until the middle of the 20th century.

The Coal Measures lie above a bed of Millstone Grit and are interspersed with sandstones, mudstones, shales, and fireclays and outcrop in the Oldham district. The Gannister Beds or Lower Coal Measures occupy the high ground of the West Pennine Hills above Oldham where the most productive seam is the Mountain mine. The Lower Coal measures were worked north-east of a line from High Crompton to Greenacres and the Middle Coal Measures to the south-west. The deepest seam in the Middle Coal Measures is the Royley mine which is equivalent to the Arley mine of the Manchester Coalfield. The coal seams dipped in the direction of central Manchester and were broken by numerous faults including the Oldham Edge, Chamber, Oak and Great Faults.

Coal was got in "Lennardyne" (Crompton) in 1552 and 70 years later Richard Radcliffe left his coal mines in Chadderton to his son. In A tour thro' the whole island of Great Britain finished in 1727, Daniel Defoe described "...Coals...upon the top of the highest hills" around Oldham. The coal seams were close to the surface and coal was easy to get.

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