Sadly, digging coal out of the ground - quite aside from the ecological aspects - is expensive. And as we discovered in the 70s, put the countries collective testicles in the gentle embrace of the NUM.
When I were a lass, we were told there were 300 years of coal under our feet.
Speaking of Scargill .... back in 1985, at he height of the miners strike, he was on QT, and he gave a piece about how the strike was so that miners sons (to be fair I may be imposing a misogyny with hindsight that wasn't there at the time) would be able to follow their fathers "down t'mine".
When the audience were asked for comments, an American young woman asked him directly why the children of miners were expected to follow their fathers instead of being teachers, doctors, lawyers, bankers, insurance salesmen, architects or indeed any other profession.
It was a teachable moment for those who learn.