 During the 1970s, Cortonwood was producing only Coke for steel plants.In March 1984, when the price of coking coal had fallen dramatically, the National Coal Board announced that the mine was due to close, due to the large stocks of coking coal that the colliery produced.The proposed closure of Cortonwood became the "final straw" in a series of closures which brought about the long-running UK miners' strike (1984–1985).