A total of 350 rescuers had drained a flooded colliery in northeast China's Heilongjiang province as of noon on Thursday, but five miners remain trapped, according to latest official updates.

A shaft of the Junyuan No. 2 Coal Mine, located in Xing'an district of the city of Hegang, flooded at 7 a.m. Wednesday, and rescuers have since worked around the clock to drain the mine, said officials with the rescue headquarters.

Twenty-eight miners were working underground when the accident happened. Fourteen of them managed to escape on their own or with help, and nine have been confirmed dead, they said.

It is estimated that 800 cubic meters of water flowed into the mine. The rescuers are now cleaning up the resulting silt and searching for the trapped miners, said Xie Diancai, vice mayor of Hegang.

The investor and the legal representative of the mine have been detained by authorities. Xing'an district government's deputy chief in charge of coal mine safety has been sacked, Xie added.

Further investigation is underway.

The Junyuan No. 2 Coal Mine is licensed, with a coal reserve of 800,000 tonnes and an annual production capacity of 60,000 tonnes, according to the Hegang city government.