Seven miners died and one was seriously injured when a colliery roof collapsed in northeast China's Heilongjiang Province, but the accident was covered up for more than two weeks, Xinhua learned Sunday.

The accident happened at 6 p.m. on July 5 at Xingcheng Coal Mine in Xing'an District of Hegang City, sources with the Heilongjiang provincial work safety authority confirmed.

Fearing to face the consequences, the mine owner deliberately covered up the accident, an official said on condition of anonymity.

He said an investigation was launched after several people provided clues of the accident to city authorities in Hegang.

Investigators talked to the mine owners, managers as well as citizens who claimed to know inside information. They also visited hospitals and a local crematory to collect evidence of the cover-up, the official said.