Dhanbad: Over 50 miners at a coal mine in Nirsa in Dhanbad got trapped on Monday after its roof collapsed. Four miners were killed after the roof of a mine in Basantimata colliery near Dhanbad caved-in on Monday. The colliery is part of the Basantimata-Dahibari cluster run by Bharat Coking Coal Limited, a subsidiary of Coal India Limited with its headquarters in Dhanbad. br ...