Former Massey Energy CEO Don Blankenship was sentenced to the maximum of one year in prison for conspiring to break safety laws and defrauding mine regulators at West Virginia's Upper Big Branch Mine, which exploded in 2010, killing 29 men. Tyler Evert /AP hide caption

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Former Massey Energy Company Chairman and CEO Don Blankenship, seen in July 2010, has pleaded not guilty to conspiracy charges associated with the 2010 West Virginia mine explosion that killed 29 men. Jacquelyn Martin/AP hide caption

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Mine helmets and painted crosses at the entrance to Massey Energy's Upper Big Branch coal mine, as a memorial to the 29 miners killed there. Jeff Gentner/AP hide caption

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At an April 25, 2010, service in Beckley, W. Va., for the 29 miners killed in the Upper Big Branch explosion, helmets — placed on crosses — were lined up in their honor. Jewel Samad /AFP/Getty Images hide caption

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