With 16 trapped miners confirmed dead on Wednesday, the death toll of a coal shaft collapse accident on Tuesday rose to 18 in northwest China's Shaanxi Province.

The accident occurred at around 11:16 a.m. at the state-owned Huisen Liangshuijing Coal Mine in Shenmu County, 600 km north of the provincial capital of Xi'an, the emergency response office of the provincial government said.

A total of 28 workers were working underground when the accident happened, but only 12 were rescued. However, two died in hospital of what the doctors described as "gas poisoning".

Rescuers had searched for the trapped miners, who were later confirmed dead.

Rescuers said heavy smoke and dust in the tunnel hampered the operation. The collapse might release huge amounts of the toxic gas in the coal layers, which would be extremely dangerous to those trapped.

Work safety officials are investigating the cause of the collapse.

(Xinhua News Agency July 2, 2008)