Coal is coal, as far as I'm concerned, and there is no such thing as "clean" coal, or even thermal coal. Moreover, coal mining, especially when it occurs underground, is no more safer, really, than it was back in the late 1950's (or before that), when a coal mine in Springhill, Nova Scotia collapsed, trapping about 74 men, killing many of them. The more recent coal mine blast in West Virginia, back in 2008, imho, is yet another indication of how unsafe coal mining generally is. The people who mine the coal are still at great risk, regarding their overall health, not to mention their very lives.
I'll also add that coal not only pollutes the air and water, but it produces more acid rain, which has a devastating affect on the environment. In addition to eroding and corroding buildings, etc., and not being good for plant life or wildlife in general, it also kills off lakes, rivers and streams, rendering them "dead" or sterile, without an ounce of wildlife or plantlife underneath the still waters.