XI'AN - Rescuers are pumping out water in the quest to free 11 coal miners trapped in a flooded colliery in Northwest China's Shaanxi province, authorities said Tuesday.

Five pumps are working around the clock.

As of 9 am Tuesday, 25 hours after the flood, around 4,600 cubic meters of water had been taken from the Zhaojin mine in the city of Tongchuan, lowering the water level by 113 cm.

Sixty-seven workers were underground when the flood occurred: Fifty-six managed to escape.

The cause of the accident is still not known.