Coal mining today has changed a LOT from the old days. In 2013, coal mining is highly mechanized and require a very different set of skills than in the past—as a result, there are a lot less people working the mines extracting out the same amount of coal. Also, coal mining in Appalachia has dropped because EPA rules require cleaning burning coal, and the low-sulfur coal from the Powder River Basin of Wyoming and Montana are surface-mined all by heavy machines.
Most of the coal miners these days have college degrees.