Eight miners trapped for five days after a mine in China caved in have been found alive, state media say.

Reports say rescue teams have not yet been able to free the survivors, but have made contact and sent in supplies.

The rock fall at the gypsum mine, in the eastern province of Shandong, was so violent that it registered at China's earthquake monitoring centre.

Nine miners are still missing. Seven have already been rescued and one is known to have died.

Rescuers used infrared cameras to peer into darkness at the wrecked mine. The cameras detected the surviving miners waving their hands.

The workers were weak with hunger but otherwise were in good health, state media reported. They told rescuers they were in passages underground that were intact.

Ma Congbo, the chairman of Yurong company which owns the mine, drowned himself by jumping into a mine well early on Sunday, China's Xinhua news agency said.

His motive was not clear but the Chinese authorities have toughened punishment of employers who are seen as negligent.

China has a long history of industrial accidents. The latest incident comes days after a landslide caused by construction waste in southern China left dozens of people missing and presumed dead.

The nation's mines have long been the world's deadliest, but safety improvements have reduced deaths in recent years.

Last year, 931 people were killed in mine accidents throughout China, significantly fewer than in 2002 when nearly 7,000 miners were killed.