Thirty-six miners trapped underground for four days in a flooded coal mine in southwest China's Guizhou Province remain missing, and local authorities are stepping up rescue efforts.

The water level in the shaft was still rising slowly though 12 pumps had been put into use to drain water from the mine, said experts who came to direct rescue work on Wednesday.

With six additional pumps put to use Wednesday night, experts said, the rising water can be contained, and only when another two high-power pumps are added Thursday night, can the water level be expected to drop drastically.

"There is still a hope for trapped miners to survive if they have self-preservation skills and there is enough air in the flooded shaft," noted a rescue worker.

The accident occurred around 12:30 Sunday when 80 miners were working underground in Tianchi Colliery, located in Xujiaba Town of Sinan County.

Forty-four workers escaped.

The cause of the accident is still under investigation.

Source: Xinhua