A gas blast at a coal mine in northern China (search) killed 20 people, the government said Sunday, just shortly after an unrelated mine explosion left 30 dead and 20 missing in the country's notoriously dangerous coal shafts.

The blast Friday in the Hougou Coal Mine (search) killed 14 miners working underground and triggered an explosion at the neighboring Shapingzi Coal Mine that killed six more people, the official Xinhua News Agency said. The accident in Shanxi province was under investigation.

The disaster came just hours after an explosion Thursday in Chengde, a city north of Beijing, killed at least 30 workers and left 20 missing. Rescuers were continuing to search Sunday for the missing at the Nuan'erhe Coal Mine.

China's mines remain the world's deadliest despite a nationwide safety crackdown and the closure of thousands of smaller, poorly equipped pits. Accidents killed 1,113 coal miners in the first three months of this year — up 20.8 percent from the same period of 2004, according to the government.