The Lofthouse Colliery disaster was a mining accident which took place in West Yorkshire, England on Wednesday 21 March 1973. Lofthouse Colliery was in Lofthouse Gate close to Outwood in the Stanley Urban District where many of the colliers lived. Its site is now in the Wakefield district. Lofthouse is further north in the Leeds district). A new coalface was excavated too close to an abandoned, flooded 19th century mineshaft. The sudden inrush of three million gallons of water trapped seven mine workers 750 feet (228.6 metres) below ground. A six-day rescue operation was carried out but succeeded in recovering only one body, that of Charles Cotton. The location of the flooded shaft was known to National Coal Board (NCB) surveyors but they had not believed it to be as deep as the modern workings. Existing British Geological Survey records indicated that the flooded shaft did descend to the same depth but these records had not been checked by the NCB. The incident led to the Mines (Precautions Against Inrushes) Regulations 1979 ("PAIR"), requiring "examination of records held by the Natural Environment Research Council which might be relevant to proposed workings [and] diligent enquiry into other sources of information which may be available, eg from geological memoirs, archives, libraries and persons with knowledge of the area and its history."