The blast on Sunday in Shilin town, Sichuan province, occurred when 17 miners were underground, the State Administration of Coal Mine Safety said on its website.
Rescuers hauled eight bodies from the shaft and brought the other nine workers to the surface, only for six to die later in hospital from their injuries. The remaining three were receiving treatment.
The coal mine, which has an annual capacity of 30,000 tons, belongs to the Xingwen County Yinfang Mining Company Ltd.
It is the latest deadly disaster to hit the industry, which is under renewed scrutiny for its perceived lack of awareness and investment in safety measures.
In recent weeks hundreds of miners have died in accidents, including 166 people in Shaanxi province - China's worst mining catastrophe in 44 years.
Recent official figures indicated that in the first 11 months of the year 5286 miners died in China, although independent overseas labour rights groups say the government is hugely underestimating the statistics.
They say the real annual figure of mining deaths could be in the region of 20,000.