The 1969 United Kingdom miners' strike was an unofficial strike that involved 140 of the 307 collieries owned by the National Coal Board, including all collieries in the Yorkshire area.[1] The strike began on 13 October 1969 and lasted for roughly two weeks, with some pits returning to work before others. The NCB lost £15 million and 2.5 million tonnes of coal as a result of the strike.[2]