From Wikipedia

In the 1950s and 1960s around a hundred North East coal mines were closed.[19] In March 1968, the last pit in the Black Country closed and pit closures were a regular occurrence in many other areas.[20] Beginning with wildcat action in 1969, the National Union of Mineworkers became increasingly militant, and was successful in gaining increased wages in their strikes in 1972 and 1974.[21] Closures were less common in the 1970s, and new investments were made in sites such as the Selby Coalfield. In early 1984, the Conservative government of Margaret Thatcher announced plans to close 20 coal pits which led to the year-long miners' strike which ended in March 1985. The strike was unsuccessful in stopping the closures and led to an end to the closed shop in British Coal, as the breakaway Union of Democratic Mineworkers was formed by miners who objected to the NUM's handling of the strike.[22] Numerous pit closures followed, and in August 1989 coal mining ended in the Kent coalfield.[23] Since 1981 production fell sharply from 128 to 17.8 million tonnes in 2009.

Prior to the strike there were 20 closures proposed. After the strike the industry was all but shut down entirely.

If that does not highlight the difference between economic and political closures to you then there is no point in anyone else trying to explain.

DtG