Obama just got off national TV. He is blaming management for the accident. He gave no facts, just his conclusion "Management did it". Union people are always happy to hear that.
The real cause of the explosion was methane gas, which escapes from the coal. There are published standards for this, how much methane is allowable, periodic tests that must be run, and a requirement for ventilation. Obama did not discuss these issues at all. He did not show that mine management allowed methane to exceed published limits, failed to run required tests, or failed to ventilate the mine.
Management is strongly motivated to prevent their multi billion dollar mine from blowing itself to kingdom come. There is no return on investment after the investment blows itself away. If management was venal or incompetent Obama gave no evidence to support that view.
Citing a number of safety writeups from government inspectors is unconvincing. I used to be in that business. When I was inspecting, I could always find things to write up. Longer I looked, the more I could find. Unless it can be shown that methane was allowed to accumulate before the accident, it ain't management's fault.