Even if there were no political interventions discouraging the use of coal, little of the coal used in the UK would be extracted in the UK. Although the country is coal-rich, as you say, it requires expensive deep mining techniques and can’t compete with lower-quality imports extracted more cheaply. British coal hasn’t been competitive since the Thatcher government privatised the industry in the 1980s. British coal will remain where it is until its extraction again makes economic sense - as is inevitable sooner or later.
Our surface miners are three times more productive than our deep coal miners. The surface mines are also much safer and it can be done in environmentally friendly ways.