China's coal mines are the deadliest in the world [Reuters]

Forty-five miners have been rescued after a 36-hour rescue operation at the Qianqiu coal mine in central China, following a rock explosion.

On Saturday, state broadcaster CCTV showed rescuers carrying the workers out of the mine shaft to ambulances, in the city of Samenxia in Henan province.

Seven miners were rescued on Friday and state media said eight miners had died in the blast. 

The tunnel within which the miners were working had "basically folded" a little more than halfway down the passage, at 480 metres, following the explosion, the Xinhua news agency said.

At least 200 workers dug a small rescue tunnel of about 500 metres deep to reach the trapped miners, the People's Daily newspaper said.

The Qianqiu coal mine belongs to Yima Coal Group, a large state-owned coal company in Henan, the State Administration of Work Safety said on its website.

Luo Lin, head of the State Administration for Work Safety, said more work needed to be done to promote safety.

"The alarm bell of work safety must keep ringing. Enterprises should pay attention to work safety when the coal demand is high," Lin said.

"They should no allow any operation that violates [safety] rules or regulations."

China's coal mines are the deadliest in the world, despite an improvement in the industry's safety record in recent years, with the closure of smaller, illegal mines.

Annual fatalities are now about one-third of the high of nearly 7,000 in 2002.

Last Sunday, a gas explosion at a coal mine in central China's Hunan province killed 29 workers, the worst accident in recent months.

Source: Agencies