Better than feared

While earlier reports sounded like complete disaster, it seems that most of those Chinese miners got out, according to a report by UPI:

The death toll was at least 30 with seven miners still missing Monday in a gas-leak accident in a coal mine in China, officials said. Rescuers said the missing miners could be buried in coal dust. Four bodies were recovered Monday.
The State Administration of Work Safety said 276 miners were working underground in a mine in Yuzhou City when a gas leak was detected Saturday and more than 2,500 tons of coal dust smothered the mine, Xinhua reported. Two-hundred-thirty-nine miners were able to escape.
An initial investigation found that more than 175,000 cubic yards of gas spread out into the mine. Liu Wenbin, a deputy chief engineer of Pingyu Coal & Electric Co. Ltd., that owns the mine, was in the pit when the leak was detected and organized the escape, the report said. "At around 6 a.m., I felt there was something wrong with the airflow in the shaft and one of the team captains told me he also felt it and had already reported the problem," Liu said.