I don't follow every law passed in Congress.
I do know that Obama has several times prided himself on moving the US to a greener energy economy. Surely there is something there to substantiate those remarks, no ?

A war on coal doesn't have to be by law or regulation. Perhaps by subsidizing competing energy sources or just vocal encouragement from the President to ditch coal.

Now, you may be right about it being high time to let this industry go. But you can't expect a CEO of a coal mining company to see it this way. Also, people cannot expect this industry to die off but at the same time get mad because workers from said industry are laid off in a fashion that is unfavorable to Obama.

btw, I'm not saying firing all those people isn't in part a publicity stunt. If those 156 would be fired in two weeks it would get zero media coverage.