By Song Shengxia

Rescuers get ready to descend the mineshaft Sunday to search for survivors at the site of the accident at the Xinxing Coal Mine in Hegang city, in Northeast China's Heilongjiang Province. A total of 103 bodies of miners had been found as of last night, and another four were still trapped in the shaft, local authorities said. Photo: Xinhua

At least 104 were killed and another four were still trapped last night after a gas explosion ripped through a coal mine early Saturday morning in Hegang, Heilongjiang Province in northeast China.

The explosion occurred at around 2:30 am at Xinxing Coal Mine, property of the State-owned Heilongjiang Longmei Mining Holding Group's subsidiary in Hegang, the Xinhua News Agency reported Sunday.

Of the 528 miners who were working in the pit when the blast occurred, 420 managed to escape.

Rescuers were still trying to reach the trapped miners, Liu Fukun, an official with the Heilongjiang Work Safety Bureau, told the Global Times late Sunday.

The manager of the mine and two other executives have been removed from their posts.

Concerned by the accident, President Hu Jintao and Premier Wen Jiabao sent Vice Premier Zhang Dejiang to the scene at 3 pm Saturday to oversee the rescue efforts, according to a CCTV report.

Li Zhanshu, governor of Heilongjiang, said at a televised meeting Sunday that he is responsible for this tragedy as the provincial leader.

Six severely injured miners, among 63 who suffered injuries, had been declared out of danger by last night.

The blast was so violent that it rocked the surrounding area, with buildings close to the mine reported to have partially collapsed, with some survivors knocked unconscious temporarily.

"My acquaintances and I are unwilling to work for coal mines because the work conditions are dangerous," a businessman surnamed Wang, who has been in Hegang for over five years, told the Global Times after the blast.

Wang said he was concerned for the trapped workers, and the accident itself shook him a lot.

"I was told the mine is a State-owned one and is supposed to be safe for miners," he said.

Longmei Mining Group is a key State-owned mining company with an annual output of 56 million tons of coal. It ranked 12th among China's top 100 mining companies and seventh out of the top 50 in terms of coal output, according to its official website.

The Xinxing coal mine has been operating for 84 years, with an annual production capacity of 1.45 million tons.

In March 2008, a fire broke out in Taiyuan mine in Hegang, killing 13 miners.

In September of the same year, Fuhua mine, in the same area, caught fire, claiming 31 lives. The accident comes after the Chinese government strengthened its efforts to clamp down on unsafe mining operations, by closing small, private mines. The efforts appeared to have been paying off.

In the first nine months of this year, China reported 286 fewer mining-related accidents and 591 fewer deaths than during the same period last year. The death toll is 25 percent lower than last year, according to figures released by the State Administration of Work Safety.

Last year's coal mine deaths were 46.7 percent fewer than in 2004, the figures show.

Fang Xinqiu, an associate professor at the China University of Mining and Technology, said poor management and inaction by mine leaders are behind the deaths at Xinxing.

The mine's gas detectors triggered an alarm 53 minutes before the blast occurred, the Beijing Youth Daily reported.

"State-owned mines have better management compared with smaller mines, but there are still loopholes," he said.

Xie Yaoshe, also an associate professor with the university, said that coal mine owners in China are more willing to pay fines than to spend a great amount of money on workplace safety equipment or personnel training.

However, the two experts, together with Lu Jianzhang, deputy director of the China Coal Research Institute in Beijing, all suggested that gas explosions in China's coal mines are almost unavoidable.

China's complicated geological conditions make it harder to ensure completely safe production in mines compared with the United States, Australia and some other countries, Lu said.

"Different plates move and converge to form the Chinese territory. Coal layers are always squeezed, and accidents are likely to occur under such geological conditions," he said.

The strong demand for coal, especially during winter, will likely prompt coal mines to increase production to meet the needs for winter heating supplies and economic growth, he said.

Many mining accidents occur between October and February, the winter season.

The country has closed 12,000 illegal coal mines since 2005, and has vowed to cut the number of the country's remaining mines to below 10,000 by 2010.

In a separate development, a coal mine blast also occurred Sunday morning in Huaihua, in central China's Hunan Province, killing at least six, according to Xinhua.

Guo Qiang and Liang Chen contributed to the story