I stand corrected on the "Big Mine" coal production. I had been told by a Crested Butte resident who had been around there when the Big Mine was open that it produced both anthracite and high-grade bituminous. Apparently, he was mistaken (he was in his late 80's when I talked to him 25+ years ago).
As to the posts about Mid-Continent, it always had a reputation of being a pretty dangerous mine. I knew some guys who worked there that later went to work at some of the other mines over on the North Fork. I don't remember any of them regretting leaving the Mid-Continent.
I also did not mean to imply that coal mining is always a safe profession--but then again, driving down the highway isn't exactly risk-free, either. (Nor is railroading always the safest of avocations . . . )