An excavator prepares the rescue work near the pithead in a copper mine pit at Dajipu township of Huangshi city, central China's Hubei Province, March 31, 2007. A flooding accident happened in the mine at about 1:00 a.m. Saturday when 21 miners were working underground. Six miners were trapped when the mine was flooded and other 15 miners managed to escape. At present, the rescue work is underway. (Xinhua/Hao Tongqian)

A rescue operation is underway to save six workers trapped underground after a copper mine flooded in central China on Saturday, but local officials say their chances of survival are slim.

The accident occurred at about 1:00 a.m. when 21 miners were working below ground in Dazhishan copper mine in Dajipu township of Daye city, Hubei province. Fifteen managed to escape unaided.

The flood cut off electricity, stopping the water pumps. By 7:00 a.m., the pit had filled with 21,000 cubic meters of water and the water level was only 30 meters from the mouth of the 450-meter pit.

Rescuers began to pump the water from 8:00 a.m., but local security officials said the work would take time. The exact location of the trapped miners is still unclear.

Geological experts said the cause of the flood might have been surface water. The local government has ordered all mines in Daye to suspend operations until safety inspections have been carried out.

A rescuer goes out from the pithead after examination in a copper mine pit at Dajipu township of Huangshi city, central China's Hubei province, March 31, 2007. A flooding accident happened in the mine at about 1:00 a.m. Saturday when 21 miners were working underground. Six miners were trapped when the mine was flooded and other 15 miners managed to escape. At present, the rescue work is underway. (Xinhua/Hao Tongqian)

A rescuer tests the flux of the drainage in a copper mine pit at Dajipu township of Huangshi city, central China's Hubei province, March 31, 2007. A flooding accident happened in the mine at about 1:00 a.m. Saturday when 21 miners were working underground. Six miners were trapped when the mine was flooded and other 15 miners managed to escape. At present, the rescue work is underway. (Xinhua/Hao Tongqian)

Journalists gather around the spot of accident in a copper mine pit at Dajipu township of Huangshi city, central China's Hubei province, March 31, 2007. A flooding accident happened in the mine at about 1:00 a.m. Saturday when 21 miners were working. Six miners were trapped underground when the mine was flooded while 15 miners managed to escape. At present, the rescue work is under way. (Xinhua/Hao Tongqian)

Editor: Yan