Manchester Coalfield

The Coal Measures lie above a bed of Millstone Grit and are interspersed with sandstones, mudstones, shales, and fireclays.

The Lower Coal Measures occupy the high ground of the West Pennine Moors above Bolton and are not worked in the Manchester Coalfield.

The early coal pits were dug to the shallow seams where they outcropped, particularly in the Irwell Valley and in Atherton.

A group of independent companies formed Manchester Collieries in 1929, to work the reserves of the coalfield.

Workable seams are close to the surface and coal from the deep Roger mine was considered to be of the highest quality.