I have several miners in the family and believe me this thing was painful to watch. Let me at least dispell a couple of myths in this thread...
College degrees in mining are few except maybe for the surveyors and engineers, which there aren't many of. Those guys aren't underground all the time anyway. Miner training is more like 2-4 weeks of vocational and safety training with annual retraining. All these NPR quotes and estimates of as much as $75K are too high, more like $30-40K. Maybe $50K after 5-10 years. Don't know anyone making 75. Specialists, electricians, and foremen might make a couple of bucks more on the hour, but there's not that much difference. Benefits are so-so, but turn over rates and company bankruptcy rates are pretty high, so there's not much continuity. Very few people get company pensions. Changing jobs, company bankruptcy or reorganizing under a different name every 3-4 years is pretty common. Timswim78 made a good point about the areas being rural and not many jobs. For a high school grad it beats minimum wage 3-times over.
As for safety, it is a pretty dangerous job. Accidents with equipment and smaller rock falls that affect only 1 person probably cause the most injuries and deaths, but big tragedies like this can take their toll too. Air supply usually isn't an issue. During normal operations there's frequent air quality and quantity testing to make sure the workers are safe. They go to great lengths with large outside fans, air barriers, dust control systems, and extensive air control plans to keep it that way. In most cases, there's redundancies with several pathways to permit airflow, access, and escape. Most mines have 3-4+ separate entries. They're somewhat closely spaced, but it takes a pretty big disaster to completely seal a mine or trap miners. When there's an explosion, rock fall, or fire or something, it interupts that flow pattern so much that it's hard to predict what the effect will be. I guess the logic with the emergency air is that if you survive the initial blast or rock fall then 1-2 hours of air is enough to get you to one of those alternate entries or back in the air flow pathway. Several miners at the same time trapped or without air for any length of time is a catastrophy none of us wants to think about.
Hope it's been informative.
EDIT: PS - If you're into prayer, say a few kind words for the families...