The miners were trapped in the Aiwei'ergou coal mine in the provincial capital of Urumqi, in China's Innjiang Uygur Autonomous Region, Xinhua reported Sunday.
Officials said no signs of life were detected in the mine following 20 hours of rescue efforts. A preliminary investigation found the accident was caused by an outbreak of gas.
The mine was undergoing a large project to increase annual production to about a million tons of coal annually.
NBC reportedly holds celebs hostage to Jimmy Fallon's show
Aaron Carter is still in love with Hilary Duff