Rescuers prepare to get down a shaft of the flooded Wangjialing coal mine to search for trapped miners in north China's Shanxi province, April 6, 2010. [Photo/Xinhua]

The rescue operation at a flooded mine in North China's Shanxi province has entered its most challenging phase, as rescue workers struggle to reach the last group of 32 miners trapped in the lowest levels of the pit.

Rescue teams found the bodies of five workers in the Wangjialing coal mine on Monday night. These were the first fatalities to be announced after 115 men were pulled out alive earlier in the day, according to the rescue headquarters.

The death toll rose to six on Tuesday afternoon, according to Shanxi Governor Wang Jun.

Before the major breakthrough in the rescue effort on Monday, a total of 153 workers had been trapped deep underground for more than a week after the mine flooded on March 28.

Operation temporarily suspended after hazardous gas accumulates

The underground search for the remaining 32 miners was temporarily suspended when it was discovered that a highly explosive gas had accumulated in the pit, Liu Dezheng, spokesman for the rescue headquarters, said at a press conference on Tuesday.

Earlier, Liu said the rescue teams had located the men, though their conditions remained unclear.

In addition to the threat of a gas explosion, rescue workers still faced the difficulty of pumping out the water that blocked the passage to the lowest part of the shaft.

According to Liu, headquarters was adjusting plans to overcome these new challenges in the rescue effort.

Of the 115 rescued miners, most of them were in stable physical conditions, with 26 showing relatively serious symptoms but without threats to their lives. All were under medical treatment in hospitals across three cities of Shanxi.

Some of the survivors have recovered so well that they had their first full meal in the past ten days.

"I want to eat meat," one unidentified survivor, holding a palm-sized bowl of noodles with egg, tomato and bean curd, told nurses in the Shanxi Aluminum Plant Hospital, where 26 survivors had been taken.

"Sausage would be better," he added as he set about eating the noodles.

Another man in his 30s said he preferred steamed bread.

"The miners are still too weak to eat solid food after being starved for more than a week," said Liu Qiang, deputy director of the medical team with the rescue headquarters.

He said the survivors were only given glucose and rice porridge shortly after they were brought to the surface on Monday.

Along with another 59 rescued miners, Lu Jianjun on Tuesday received treatment in Taiyuan, capital of Shanxi, after they were transferred from Hejin city, one of the cities closest to the mine.

Lu, 26, a native of a village near the mine and the father of a 7-month-old infant, said he hoped the mine would be restored as soon as possible and he could return to work there.

Meanwhile, the rescue headquarters has required the mine's owner to prepare for the imminent inquiry into the accident that left the men trapped, according to spokesman Liu.

The State Administration of Work Safety has blamed the accident on the violation of safety rules during the construction of the mine.

Preliminary investigations found water had gushed into the mine after workers broke into a disused shaft that had filled with groundwater.