A gas blast early Thursday led to a fire in the Shuijingtou coal mine in Shaodong County, central China's Hunan Province, the official Xinhua news agency said.
Two miners escaped and another was later rescued but rescue efforts to find the six missing men were hampered by the fire that followed the blast.
The mine is owned by state-owned Lianshao Mining Group.
Meanwhile, another seven miners have been killed and three injured in a mine flood on Thursday in the southwest province of Yunnan, Xinhua reported.
Ten miners were working underground at the time of the flood with three managing to escape.