The rescuers also faced dangerous gas levels and the risk of falling rocks as they worked their way into the mine pit.

The early-morning explosion in central China happened as the world still was celebrating Chile’s successful rescue of 33 miners trapped more than two months. Chinese media had detailed coverage as the men emerged to cheers.

Some in China asked whether their own officials would make as much of an effort in a similar disaster, and be just as open about the progress of rescue efforts.

The test came quickly for China, whose mining industry is the most dangerous in the world.

Saturday’s blast at a state-run mine in Henan province occurred as workers were drilling a hole to release pressure from a gas buildup to decrease the risk of explosions, the state work safety administration said.

Another gas blast at the same mine two years ago killed 23 people, state media said.

Saturday’s blast at the Pingyu Coal & Electric Co. Ltd. mine unleashed more than 2,500 tons of coal dust, an engineer for one of the mine’s parent companies, Du Bo, told the state-run Xinhua News Agency.

A rescue spokesman told Xinhua that workers had located the 16 trapped miners but must clear tons of coal dust from the mine shaft to reach them.

It wasn’t clear if the miners were alive or how far underground they were trapped in the mine in the city of Yuzhou, about 430 miles south of Beijing.

China Central Television’s news channel had an excited live broadcast from the mine early in the afternoon, but then did not mention the accident for several hours, and there was no word of it on the main TV evening news. A report later in the evening consisted mostly of information from the state news agency read by an announcer, suggesting that authorities had decided to limit reporting on the accident and rescue efforts.

The gas level inside the mine was 40 percent, far higher than the normal level of about 1 percent, state media said. The gas wasn’t specified, but methane is a common cause of mine blasts, and coal dust is explosive.

The more than 70 rescuers working in shifts at the scene also must clear chunks of coal loosened by the blast that fell into the shaft, Xinhua said.

At least 21 miners were confirmed dead, it said.

China celebrated its own stunning mine rescue earlier this year, when 115 miners were pulled from a flooded mine in the northern province of Shanxi after more than a week underground. The miners survived by eating sawdust, tree bark, paper and even coal. Some strapped themselves to the walls of the shafts with their belts to avoid drowning while they slept.

But it was a rare bright spot. About 2,600 people were killed in mining accidents last year, and the country’s leaders have been making a high-profile push to improve mine safety.

Premier Wen Jiabao this summer even ordered mining bosses into the mines with their workers or else risk severe punishment.

Mining deaths decreased in recent years as China closed many illegal mines or absorbed them into state-owned companies, but deaths increased in the first half of this year. At least 515 people have been killed nationwide in coal mines alone so far this year, not including Saturday’s blast.

An unknown number of illegal mines still exist to profit from the fast-growing economy’s huge appetite for power.

China’s economy remains reliant on coal for about two-thirds of its energy needs.

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Associated Press researcher Henry Hou contributed to this report.