Donetsk (Ukraine) (AFP) - Nearly 500 coal miners in Ukraine's war-torn east were trapped on Monday after their pit lost power when a shell hit a regional electric substation.The accident occurred in rebel-controlled Donetsk city's Zasyadko coal mine -- one of eastern Europe's largest, where the same type of incident briefly trapped 300 miners on January 11."When the power went out, there were 496 miners underground," a Donetsk region emergencies ministry official told AFP by telephone.