Members of the investigation panel of China's State Council look at an illustration of water drainage of at the Xinjing Coal Mine in Zuoyun County, north China's Shanxi Province, May 27. (Xinhua Photo)

An initial investigation shows the mine flooding in north China's Shanxi Province was caused by water pouring in from a worked-out section of a neighboring mine, said rescue headquarters Saturday.

Preliminary analysis indicate that miners accidentally dug into the disused, water-filled section and flooded the shaft in which they were working, said Li Yizhong, director of the State Administration of Work Safety.

It's estimated that 200,000 cubic meters of water filled the mine, and about 50,000 cubic meters have been pumped out, according to reports from headquarters on Saturday.

The flooding occurred at around 8.30 p.m. on May 18 at the Xinjing mine in Zuoyun County, in north China's Shanxi Province.

Rescuers are still pumping although hope of finding any of 56 trapped miners alive is slim.

Li Yizhong (C), director of the State Administration of Work Safety, gestures while listening to the introduction of rescuers at the Xinjing Coal Mine in Zuoyun County, north China's Shanxi Province, May 27. (Xinhua Photo)

The number of miners that were trapped has been revised from 57to 56, as trapped miner He Mingzhi used the duty card of He Jiang, who was also believed to have been trapped but has been confirmed by police to have left the mine before the accident.

Meanwhile, four more people, including labor contractor Duan Jingli and three water detection workers at the mine, have been detained. This brings the number of people in police custody to 19, said the headquarters Saturday.

Police on Friday arrested Zhang Shengsheng, a key suspect in charge of mining and work safety of the Xinjing mine, and detained two bank officials who were suspected to have been involved in the accident.

A panel authorized by China's State Council was set up at the Xinjing mine Saturday, which will conduct a thorough investigation of the accident.

Editor: Yan