Five miners were trapped underground Saturday afternoon when the coal mine they were working in collapsed and was flooded with mud in Zanhuang County, northern China's Hebei Province, officials said Sunday.

Li Lichuan, an eyewitness who was working with the five trapped miners when the accident occurred, said they had been trapped in the mine shaft by a sudden influx of mud.

Li said that only he had managed to escape to the surface.

Sixteen rescue experts from the Xingtai and the Jingxing mining bureaus are conducting the rescue work in five teams of 11 workers each.

To date, there is no indication whether the trapped miners are dead or alive.

The first rescue team returned to the surface Sunday afternoon, saying that the work had progressed well although they were still nine meters from their goal.

Rescue experts predict that the rescuers will be able to advance only 1.5 meters underground every four hours.

"Preliminary findings show that an ancient mine from the Qing Dynasty (1644-1911) located in the area of the mine collapsed and generated the mud flow," said Wu Shimao, magistrate of Zanhuang County.

Experts are still investigating the exact cause of the collapse.