Rescue efforts are still underway and an investigation has been launched, reports the state-run Xinhua agency.
The flood occurred about 9am Thursday at a mine in the city of Zhangqiu, according to the press office of the municipal government of Jinan, which administers Zhangqiu.
It confirmed the mine was being operated illegally. The colliery owner and others have been detained.
According to economic figures from the Chinese National Bureau of Statistics, last year’s coal mine death toll was down 33.75% on 2011. But its safety record remains one of the worst in the world.
Government efforts to stamp out hazardous mines have resulted in the closure of more than 9000 small coal operations 2006.
In September, Chinese authorities pledged to shut down 20,000 illegal and unsafe mines by 2015 following a string of deadly gas explosions and collapses.
