VIDEO: China Mine Shaft Death Toll Rises To 18

The privately owned Changlong mine in Qitaihe, in Heilongjiang, was operating legally and had an annual production capacity of 40,000 tonnes, Xinhua said, adding that the cause of Sunday's explosion was under investigation.

The rescuers were from a professional mining accident rescue team owned by Longmei Colliery Group in the city. More than 100 rescuers were involved in the rescue operation, Xinhua said.

China is trying to curtail the grim fatality rate of its mining industry by shutting down small and unlicensed operators. But even in many legal mines, overproduction hinders safety.

In the first 10 months of this year, 2,690 Chinese miners died in explosions, gas leaks, flooding and cave-ins, a drop of 13 percent from the same period last year, according to the State Administration of Work Safety.

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