JIXI, Heilongjiang - Two mine managers have been detained for their cover-up of a coal mine flood accident in Northeast China as rescue efforts continue for the 16 remaining trapped workers, police said Saturday.

Zhou Xiaowei, owner of the Anzhishun coal mine in Jixi city,Heilongjiang province, and another senior manager in charge of production were detained.

Water flooded the mine at 1:10 pm on Thursday when 56 workers were in the shaft, but the mine's management reported to authorities that only nine were trapped.

Work safety investigators found that 31 of the 56 workers were lifted out of the shaft after the accident. Twenty-five were trapped underground, with nine rescued alive about 20 hours after the accident.

Rescue work is under way for the remaining 16 trapped people.

The licensed private mine has an annual production capacity of 60,000 tonnes. The assets of the mine owner have been frozen.