The death toll from a rain-triggered mud-rock flow in north China's Shanxi Province rose to 56 as of 6:00 PM on Tuesday, the local rescue headquarters said.

Another 35 injured were being treated by five experts and more than 150 medical personnel. Most had suffered fractures and were in stable conditions.

Among the five seriously injured workers, four were transferred to Linfen People's Hospital after operations. But one patient suffering necrosis on the right leg was still in danger as of 8 p.m. on Tuesday, doctors said.

A team of more than 1,550 police, firefighters and people, with 30 cranes and excavators, had participated in the rescue operation.

The rescuers had searched through about 70 percent of the rubble, said Lian Zhendong, a local government official.

But rough terrain, poor telecommunications and continuous rainfall had hampered the rescue effort.

The accident occurred around 8:00 AM on Monday in a pond holding waste ore dregs of the Tashan Mine in Xiangfen County, Linfen City, which was soaked by torrential rain.

The mud-rock flow also destroyed a three-storey office building, a market and some village houses in the valley.

Witness said the flow roared down the valley and washed away the market and houses in a few minutes.

An initial investigation revealed the accident's cause was "the unlicensed Tashan mine operated illegally and the stored waste iron ore dregs had surpassed the capacity of the holding pond," said the rescue headquarters.

Police said the mine owner and eight others related to the accident were detained. Several officials, including the local head of the work safety administration, village Party secretary and village chief have been sacked for failing to supervise safety.

There are several other ore mines in Xiangfen. The staff there are mostly migrant workers from Shanxi, Chongqing and the central Hubei Province, which makes it difficult to identify the victims, rescuers said.

The State Council, or China's cabinet, is going to start investigation into the cause of the accident soon.

The specific number of people trapped underneath the rubble is still under investigation.

(Xinhua News Agency September 9, 2008)