Chinese television said the blast happened early on Tuesday at a mine in Hegang in Heilongjiang province.
China has a poor record of safety in mining.
Official figures say that some 5,000 miners were killed in accidents last year, though independent estimates put the number as high as 10,000. North Korea develops tourism link Cambodia rejects logging report Malaysian students challenge security law Burma talks to resume Links to more Asia-Pacific stories are at the foot of the page.