HONGTONG, Shanxi - More than 600 rescue workers pumped water out of a flooded coal mine to rescue 12 trapped workers on Thursday in North China's Shanxi province.

Four of the trapped workers have been confirmed to be alive, and the conditions of the other eight remain unknown, according to a spokesman with the accident rescue headquarters of Ji'anda Coal Mining Co., Ltd of the Shanxi Luhe Coal-Chemical Group.

More than 2,500 cubic meters of water were pumped out of the coal mine from 10 am Wednesday to 9 am Thursday, and an estimated 7,700 cubic meters of water still needed to be pumped, said the spokesman.

Rescuers are also rushing to dig a well to allow adequate ventilation for those still trapped in the pit.

The accident occurred at 4:17 am Wednesday at a pit under construction, which is located in Hongtong county, Linfen.

Twenty-two people who were working underground at that time escaped from the flooded shaft.

The mine, with a designed annual production capacity of 1.2 million tonnes, is co-owned by the SLCCG and the holding company Yunfeng Group, a Shanghai-based group with interests in real estate, energy and chemical engineering under the Greenland Group.

The cause of the accident is being investigated.