Two owners of a coal mine in northeast China's Liaoning Province were detained for covering up a coal mine blast, which caused six deaths, for more than a month, said local authorities Wednesday.

A three million yuan fine was also handed down by the provincial administration of coal mine safety Wednesday to the owners, Zhou Yangui and Qin Fengxin, of the Xincheng mine in Benxi city.

The explosion happened 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 an investigation into the accident on May 19 after receiving a tip-off about the cover-up, the official said.

An investigation into the accident is still underway.