The Coal Authority has records of over 175,000 mine entries within the UK captured in the National Coal Mining database, derived from sources including abandonment plans, geological and topographical plans. Coal mining activity is recorded as far back as the 13th century, but prior to 1872 there was no requirement to deposit abandonment plans. It is therefore believed there may be many unrecorded mine entries of which the Authority has no information or knowledge. These entries do not, therefore, appear within the Authority's national dataset as described here.