All seven people trapped in a coal mine tunnel collapse in northeast China's Heilongjiang Province were rescued on Tuesday after a 31-hour rescue operation.

The accident took place at around 4:47 a.m. BJT on Monday, when one of the underground tunnels caved-in at Dongrong No.2 coal mine, which is owned by the Shuangyashan branch company of the Longmay Mining Holding Group – the largest coal mining company in northeast China.

An investigation has been launched into the cause of the accident.

(CGTN reporter Guan Yang also contributed to the story)