With time the creation of coal ceased and new geological formations were created.

• Concealed coalfields are fields where the newer geological formations have covered the coal.
• Exposed coalfields were not covered and were therefore left exposed.

The coalfields within reach of the Ilkeston Mines Rescue slope to the east, away from the Pennines but there are local exceptions. The local uplift of the strata which stretches from Codnor Park, in the north, through Langley Mill to Cossall and Trowell in the south. The area to the west of this, including Heanor, is in the shape of a huge basin which is known to geologists as a syncline. The syncline extends from Stanton by Dale in the south to Crosshill in the north and from Belper in the west to the anticline in the east.

The East Midland association with coal stretches back hundreds of years. Coal from the exposed seam on the western edge of Nottinghamshire was comparatively easy to obtain using primitive methods. The recent growth in open casting has revealed evidence of medieval workings, including timber-lined shafts in Leicestershire, pillar and stall workings and bell pits in Strelley where, as at Cossall, Selston and Wollaton, coal was mined but served only a small local market. Unfortunately although opencast coal extraction reveals older workings it also quickly destroys the evidence.

The Bell Pit was one of the earliest forms of underground mining where a central shaft was sunk into the seam. The miners then worked outwards from the shaft until the pit roof was in danger of collapsing whereupon the bell pit would be abandoned and a new shaft would be sunk nearby. The materials would be hoisted up on a wooden rope winch or windlass with a basket attached to it.

Circular indentations in the ground, with a growth of young trees about it, often indicates the presence of an old bell pits.

Pillar and Stall. In this early form of mining the workings were set out in squares to gain maximum support in the shallow seams. Roadways were driven through the seam at right angles to one another (stalls) and alternate blocks of coal were removed leaving pillars of coal. These pillars gave good roof support but wasted a lot of coal.

Longwall. Modern day mining has its roots in this system which relied on men working three shifts. It is thought that the sytem was 'invented' in the Shropshire minefields. John Farey, writing in 1811 described the system.
Firstly a night shift of Holers undermine the entire seam of coal on the bank or face, they do this by chipping away at the bottom of the seam with a pick thus creating a wedge at the bottom of the coal (Undercutting). Small wooden props are placed at intervals along the face to support the seam. At one or both ends of the face a vertical cut is made to allow the next shift to drop the coal from the gate end along the length of the bank.
Secondly the Hammermen or Drivers drive long sharp iron wedges into the top of the seam with hammers which allows the coal to drop in large blocks many yards long. The Drivers are followed by a Rembler who breaks up the coal into manageable pieces for the Loaders to load into the tubs or boxes for transportation. Most tools were made of wood until late into the eighteenth century as the expense of iron tools made them prohibitive to use.
The coal was loaded into the tubs using wooden forks at many local mines so as not to include slack and a ton of coal for a collier to load was twenty-two or more hundredweight to allow for any dirt or slack.
Thirdly the final group of men the Timberers or Punchers bring in seasoned timber supports cut from local woods or plantations to support the roof. The face is ready for the system to start up again.