Rescuers recovered 14 bodies of the miners late Saturday evening who were trapped at the flooded Shangjiuwu coal mine in Ruzhou city, southwest of the provincial capital Zhengzhou.

Coalminers gather at the colliery as rescue work continues after a flooding in the mine in Ruzhou, central China's Henan Province, March 24. [Xinhua]

A high density of gas and lack of oxygen led to the deaths, according to Li Jiucheng, director of Henan Coal Mine Safety Administration.

The accident occurred around 11 p.m. Thursday when 52 miners were working inside the mine.

Mine managers organized rescue operation themselves without reporting the accident immediately to local work safety administration authorities.

The local government received a report of the accident from local residents Friday morning and began organizing rescue operations.

The privately-owned mine had been upgrading production facilities before the accident. It had won government approval to raise its annual capacity from 90,000 tonnes to 150,000 tonnes.

Police have detained mine owner Wang Xianguo and are searching for the other two runaway mangers.

The bank account of the mine was also frozen.

The cause of the flood is being investigated.

In a separate accident, a gas blast last Sunday killed 21 miners at a coal mine in north China's Shanxi Province, a major coal production base in the country.

China's coal mine accidents killed 4,746 people in 2006, according to the State Administration of Work Safety.