At least 30 people have died as a result of a blast at a coal mine in South Khorasan province, Iran.The director general of the provincial crisis management department reported that the explosion occurred while 69 workers were present in the mine.He explained that the explosion did not involve a fire or destruction of walls, noting that the release of methane gas in the tunnels caused the workers inside the mine to suffocate.In September last year, six people lost their lives due to an explosion at a coal mine in Semnan province, northeastern Iran.