Tragedy struck a rescue operation in a north China colliery Sunday when rescuers found the lifeless bodies of four miners trapped after a cave-in, the government said.

One miner remained missing after the incident Friday morning at the Yuanlin coal mine in Inner Mongolia, the government said in a statement.

The cave-in initially trapped 12 workers, but seven were rescued over two days.

The deaths came after the state-run Xinhua news agency reported Saturday that rescuers had made contact with the five trapped miners and were giving them food and water through a lifeline drilled by rescue workers.

The accident is the latest in an industry plagued by corruption and safety hazards.

Earlier this month, at least 34 workers were killed after a blast at a mine in the southwestern province of Yunnan, state press reported.

China's rapid economic growth has brought rising demand for power. It relies on coal for 70 percent of its energy needs, making it the world's largest consumer of the fossil fuel.

Last year, 2,433 people died in coal mining accidents in the country, according to official statistics -- a rate of more than six workers per day.

Labour rights groups, however, say the actual death toll is likely to be much higher, partly due to under-reporting of accidents as mine bosses seek to limit their economic losses and avoid punishment.