A coal mine blast in northeast China's Liaoning Province, which caused six deaths, was exposed Tuesday after having been covered up for more than a month by the mine owner.

The explosion happened in a coal mine named Xincheng in Benxi city of Liaoning on April 10, killing six, but the owner concealed the accident, said an official with the provincial administration of coal mine safety.

The administration started investigation into the accident on May 19 after receiving a tip-off about the cover-up, the official said. Investigation into the accident is still underway.