The Wyoming coal does have advantages, but it has disavantages, too. For example, how do you get that coal from its location to where it is actually used (i.e. East Coast). It is also fairly low btu coal so you need more of it which exacerbates the shipping problem.
One advantage of it is its low sulfur content. However, the large utilities on the east coast are building scrubbers at a frantic rate to allow them to burn high sulfur coal on the east coast which then can get locally. So, I think applachian coal is going to be quite big over the next decade.