Survived miners recall lead-up to deadly blast

An hour before the explosion, the miners had already tested a dangerously high build-up of toxic gas. Almost 80 percent of those underground managed to escape. But more than 100 were trapped inside.

Those who escaped safely recalled the shocking moments leading up to the gas explosion.

Wang Wenbin, miner of Xinxing Coal Mine, said, "The gas build-up was like a heavy stand storm. We had to put our hands on the safety helmets to prevent them blowing away. We used the gas-test machine and we were shocked by the result. The toxic gas was 7 percent higher than the standard."

Usually, gas levels just one percent higher than the standard triggers a high alert. Evacuation plans were immediately implemented.