Well we're going to continue to need coal in possibly decreasing amounts for the next couple of decades. No way are we decommissioning all coal-fired generating any time soon. That should be enough time for natural attrition to handle the current mine workers. The effort should be in getting young people interested/trained in something else before they follow their fathers into the mines.
As long as folks like Trump keep selling them on the dream of "coal forever", they're not going to listen to common sense. Politicians see them only as votes and not as constituents to be cared for.
The UK went from 1.2 million[1] workers in the coal industry in 1920 to nearly zero now. It was painful at times though and many of the former coal towns have never really recovered.
The sad truth is that coal miners want to continue being coal miners because they have wrapped up a lot of their identity into the job.