Emergency vehicles are pictured parked outside Zasyadko coal mine in Donetsk March 4, 2015. A blast at the coal mine in the eastern Ukrainian rebel stronghold of Donetsk killed more than 30 people, a local official said on Wednesday, with dozens more miners who were underground at the time unaccounted for. REUTERS/Baz Ratner (UKRAINE - Tags: POLITICS CIVIL UNREST CONFLICT ENERGY DISASTER)