Rescuers said on Tuesday night there was no chance of survival for the 13 workers trapped in a collapsed subway tunnel in Hangzhou, capital of the eastern Zhejiang Province.

Rescue efforts lasted more than 72 hours, but because the tunnel was filled with a huge amount of silt, rescuers could not determine the location of the trapped workers.

"The tunnel is 16 meters deep and the mire about eight meters deep," said Chen Yunmin, an expert at Zhejiang University. "If the workers are trapped in the middle of the mire, it may take two or three days for rescuers to reach them. If they are at the bottom, it's hard to say when they can be reached."

Large excavating machinery will not be used in the next few days to show respect for the bodies of the deceased, said Hangzhou Mayor Cai Qi.

An expert panel is working on a plan to prevent secondary disasters as fissures appeared in the walls surrounding the accident scene.

A 75-m section of a subway tunnel under construction collapsed Saturday afternoon. So far, eight people were confirmed dead in the accident, not including the 13 still missing. Another 11 injured workers are receiving treatment at a hospital.

Four search dogs and more than 400 rescuers tried to find the trapped workers.

The China Tiesiju Civil Engineering Group Co. Ltd (CTCEG), the subway project contractor, has been working with social security and civil affairs departments in Hangzhou to discuss compensation with the victims' families, said Zi Baocheng, CTCEG's deputy Party chief.

The victims, mostly farmers from the eastern Anhui Province, apparently received little training before they started work on the subway project.

Survivor Song Changfa, who suffered a broken leg, said some of his fellow villagers had never done construction work before.

"Before they came here, they were planting wheat in their hometowns," said Song, who said he had done subway construction work in nearby Shanghai.

Song complained there were fewer supporting rods inside the subway tunnel in Hangzhou than at construction sites in Shanghai.

"In Shanghai, there is a supporting pole every few meters. If there were enough poles here in Hangzhou, my colleagues would have a bigger chance to survive," said Song.

Zhao Tiechui, deputy head of the state work safety administration, led a task force to investigate the cause of the accident. Zhao was told cracks appeared on the road surface and the roadbed had sank nearby the construction site more than one month ago.

Fu Meizhen, a local resident, recalled that cracks of 2 to 3 cm wide and a meter long had appeared on the road about a week ago, right where the collapse took place.

Fu's account was confirmed by Ye Zhiguo, a surviving welder.

"The construction company noticed the subsiding and had began to remedy it by paving the roadbed and inserting steel bars. These efforts continued until the collapse," said Ye.

(Xinhua News Agency November 19, 2008)