A federal investigation has found last year’s West Virginia coal mine disaster was preventable and followed negligence by the mine’s owner, Massey Energy. In a preliminary report [Download pdf], the Mine Safety and Health Administration says Massey repeatedly violated federal rules on ventilation and minimizing coal dust to reduce the risk of explosion. Investigators say a small flare-up of methane gas sparked a massive coal dust blast. Their report says there is no evidence to support Massey’s claim that a burst of gas from a hole in the mine floor overwhelmed safety mechanisms. Twenty-nine workers were killed in the explosion.