Four miners are trapped underground after a small coal mine collapsed in north China's Inner Mongolia Autonomous Region on Monday, local authorities said.

The cave-in occurred at 6:00 AM in a privately-owned mine in Urad Qianqi, Bayannur, when four miners from southwest China's Sichuan Province were doing maintenance work in the shaft 70 meters underground.
 
Initial investigations by local work safety administration officials have shown that the mine, owned by Zhang Shuangquan, was illegal and operating without a license.

Local government departments have called in two excavators and three loaders to clear the shaft so rescuers can search for the missing miners.

An investigation into the accident is underway.

(Xinhua News Agency April 17, 2007)