The Coal Authority has records of over 170,000 mine entries within the UK captured in the National Coal Mining Database from a variety of sources including abandonment plans, geological and Ordnance Survey plans. After 1872, there was a requirement for a coal mine owners to deposit their working plan for the mine with the State when the mine closed. Hence, there may be un-recorded mine entries to which the Coal Authority has no information or knowledge. The layer shows the best-plot position for each mine entry from the information held by the Coal Authority together with any treatment to that entry.
Mine entries indicate the entrance into a mine working, for which there are two types: shafts and adits. Mine shafts are vertical or near vertical entrances to a mine whereas adits are a walkable entrance to a mine as shown on plans held by the Coal Authority. Mine entry positions are taken from a variety of plan sources which vary in age, scale, accuracy and condition. These factors determine the accuracy of the mine entry position derived.