Beijing, Aug 4 (IANS) Four people died from suffocation in a coal mine shaft in north China's Inner Mongolia Autonomous Region, local mine safety authorities said.According to the Inner Mongolia branch of the National Mine Safety Administration, the accident occurred at about 4:25 p.m. local time on Saturday at acoal mine in Jungar Banner in the city of Ordos, Xinhua news agency reported.The exact cause of the accident is still unknown, and investigations are underway.Details of the accident are awaited.