Hundreds of rescuers are continuing to search for 22 miners Friday who became trapped underground after a gas leak Thursday morning in a coal mine in the province of Yunnan.

Twenty-one miners have been confirmed dead after a coal mine gas leak accident in the southwestern province of Yunnan Thursday, and hundreds of rescuers are rushing to save the 22 people still trapped underground. [Photo/Chinanews.com]

Ventilation machines are pumping excess methane gas out of the mine, while rescuers are taking turns braving high levels of gas, coal dust and debris in the pit to find survivors in the Sizhuang Coal Mine, located near the city of Qujing.

"The underground situation is very complicated. Only six rescuers are allowed to go down into the shaft per shift due to the high intensity of gas. Too many rescuers underground will easily trigger accidents," said a rescuer surnamed Li before descending into the pit Friday morning.

"In addition to searching for the miners, we need to examine and repair the electromechanical equipment and clear the damaged pipes and other debris that block the tunnel," he said.

"We must rescue the trapped miners at all costs," said Zhao Tiechui, deputy director of the State Administration of Work Safety, at the site early Friday.

Coal dust forced out of the shaft by expanding gas has blanketed the area around the shaft's entrance. The area has been cordoned off by police and 30 ambulances are parked outside the mine, as worried and tearful relatives of trapped miners looked on.

"Just in less than 10 minutes, my elder brother could have escaped alive," said a relative surnamed Xu at the site. He said his elder brother, 44-year-old Xu Zhengliang, was preparing to get off work and go out of the shaft via the lift when the accident happened.

"There has been no news about his condition so far. But I am afraid that the chance of survival is slight," he said.

Another trapped miner, 37-year-old Yin Jinsuo from a local village, had been the backbone of his family with a heavy burden. He needs to support three young children, his wife and 75-year-old mother.

"We just want to go to the entrance and see him for the last time," said his elder sister, while supporting Yin's wife with her hands who was crying aloud and could not speak a word.

Local work safety officials said the private mine was operating without a license when the accident occurred. The mine's license was revoked a year ago.

"It is an accident that should not have happened. It exposes a lack of supervision by the local government. We must learn a lesson from this accident," Zhao said.

A preliminary investigation showed that the gas leak occurred at one platform inside the shaft but later spread to another platform, trapping a total of 43 miners on the two platforms at about 6:30 a.m. Thursday. Twenty-one of the miners have already perished.

"We estimate that some miners might have sought shelters in a place where coal vehicles park underground. But we cannot be sure about that. As long as there is a slim hope, we will make every effort to find them," said Ning Degang, vice mayor of Qujing, who oversees the search and rescue operation at the site.