Luo Lin, director of State Administration of Work Safety, said, "The whole rescue and relief work is being carried out in an orderly and effective manner."

Zhao Tiechui, Deputy director of State Administration of Work Safety, said, "Violation of regulations during operations is the most basic cause of the accident. There was not enough coordination between the mine owner and construction units. But it's unclear who should bear most of the responsibility."

With a history dating back more than half a century, the Tonghua Coal Mine is affiliated to the state-owned Songzao Mining Bureau of Chongqing.

Local mine supervision authorities are continuing to investigate the cause of the accident. And local prosecutors are also involved in the case.