Hundreds of rescuers are searching for 23 miners who are trapped underground after a coal mine caved in late Wednesday night in northeastern China's Heilongjiang Province, the local coal mine safety supervision authorities said Thursday.

The accident occurred at 11:30 p.m. Wednesday when 23 miners were working underground at Xinyongfeng Coal Mine in Jixi city.

Preliminary investigation showed heavy rain was to blame for the cave-in in the mine, authorities said.

The cave is about 50 meters long, 60 meters wide and 10 meters deep. Rescuers estimated that 30,000 cubic meters of soil subsided.

The rescuers were digging out the soil Thursday evening. Equipment for the rescue operation has been sent to the site.

A miner named Song Xiuzhao, who was supposed to work underground when the cave-in took place, came out of the mine with a stomachache at 10 p.m., avoiding the possibly fatal accident.

Song said he wandered near the mine after he came out, because he wanted to leave together with his co-workers. He was near the mine entrance when he heard a great noise and then saw a huge cave appear several hundred meters away.

Song said it rained heavily Wednesday night. The rescuers said Jixi received 51.6 mm of rainfall Wednesday.

(Xinhua News Agency July 23, 2009)