HOHHOT, April 18 (Xinhua) -- Miners trapped in two Chinese colliery accidents still have chances of survival, rescuers said on Tuesday.

Rescuers at the site of a small coal mine in north China's Inner Mongolia Autonomous Region said the miners could have ample air supply at where they are trapped. If rescue work goes smoothly, they could be reached by rescuers soon.

The mine caved in at 6:00 a.m in Urad Qianqi, Bayannur of Inner Mongolia, when four miners from southwest China's Sichuan province were doing maintenance work in the shaft 70 meters underground.

Zhang Tianquan, owner of the mine, could not provide license for operation and has been held by local police.

In another accident which happened at around 3:40 p.m. on Monday in Changcheng Coal Mine, Zhuzhou city of central China's Hunan Province, flood trapped 12 people.

Local rescuers have installed new pumping devices and greatly boosted pumping capacity Tuesday evening. The water level has been dropping, rescuers said.

"If our calculation on the water volume is accurate, we will reach eight of the 12 miners in 15 hours. However, we are not sure when we can get to the other four," said Yan Yinchu, vice director of the provincial administration of coal mine safety.

"Even if there is only one percent chance of survival, we will spare no efforts to save them." said Yan.

Rescue teams had been dispatched from neighboring cities to help with the operation to save the trapped miners, but heavy rains had hampered their efforts. So far 3,200 cubic meters of water have been pumped out.

Changcheng Mine is a privately-operated mine with a production capacity of 30,000 tons a year. Its license and certificates were valid, the administration said.