Thirty-six miners remained trapped in the Nadu Mine in south China's Guangxi Zhuang Autonomous Region, where flooding occurred on Monday afternoon, rescuers said on Tuesday morning.

    The rescue team led by Guo Shengkun, secretary of the regional Communist Party Committee, confirmed 56 miners were working underground, when the mine flooded at 3:30 p.m. on Monday.

    Seven of the workers managed to escape, and rescuers saved another 13 miners in an overnight rescue effort. The workers have been sent to hospital for treatment.

    Rescuers said they had established contact with 12 of the trapped miners, who were stuck in a "relatively safe working face" underground.

    "They were trapped in a place about 2,000 meters from the entrance. The lack of oxygen in the narrow mining tunnel would make it difficult for the exhausted miners to get out by themselves," a rescuer said.

    Ma Biao, Guangxi's regional government chairman, and Peng Jianxun, the State Administration of Coal Mine Safety deputy director, were overseeing the rescue operation in the cordoned off area.

    Rescuers said they were trying to send mineral water and porridge to the 12 miners.

    The rescue team had yet to establish contact with the other 24 miners.

    Rescuers continued to pump water from the mine early on Tuesday.

    Huang Zhao, chief engineer of the mine, said the ventilation, drainage and lift facilities in the mine complied with regulations.

    The mine has estimated reserves of 2.98 million tons of coal and is owned by the Youjiang Mining Bureau in Baise, which began the mining in 2003.