Anguished relatives of Chinese coal miners trapped in flooded shafts clashed with managers on Monday to demand information, but hopes for the 181 men faded after another day of efforts to pump the mines dry.

The disaster in the eastern coastal province of Shandong is the latest to strike China's coal mines, which -- with over 2,000 people killed in the first seven months of this year along -- are the world's deadliest.

The miners have been trapped since Friday when a burst river dyke sent water rushing into two shafts. Rescuers hold out little hope of survival for many, if not all, of the men who could not outpace the torrent -- 172 in a main shaft and nine in one nearby.

Drilling equipment from a nearby oil field was being installed to help rescuers, and water pumps from neighbouring provinces were sent to the site.

By Monday afternoon, the water level in the main 860-metre (2,800 feet) deep pit had dropped by 21.5 metres (70 feet) from its peak, Xinhua reported. Hopes that trapped miners have survived are "extremely faint," it said.

Five or so men demanding word about trapped relatives stormed offices of the Huayuan Mining Co, which they said had not been telling families what was happening.

"We can't wait anymore," they yelled before rushing into the offices, smashing windows in a confrontation with officials they said had promised, but not given, regular information.

"Now I'm only getting information from the Internet and television. I want the company to brief us everyday at a set venue," said one of the protesting men, Zhang Chunling, who said his brother was still missing underground.

Only a day before the disaster, province safety officials meeting in Xintai discussed the threat of floods in coal mines and singled out the area where Friday's disaster took place, showing that officials knew of seasonal risks from heavy rains.

"Especially in areas along rivers and lakes and low-lying areas where water easily accumulates and leaks, we must set preventative measures," the report on the Web site of Shandong's coal mine safety bureau (www.sdcoal.gov.cn) cited deputy chief Zhang Xuechang as saying in Xintai.

Troops, armed police and miners have managed to block the levee breach on the Wenhe River, swollen from torrential rains.

One miner who escaped the shaft told reporters that the current was too strong for many.

"We saw the water, it was pouring in from the ceiling and the current was very strong," said Wang Kuitao, whose brother was still trapped in the shaft. "If you couldn't grasp onto something you would definitely be washed away."

"IT'S TOTALLY MANMADE"

China relies on coal to fuel its economic boom and with domestic coal prices at record levels, some operators boost production beyond safe limits despite government efforts to enforce safety standards.

Officials at the disaster site have called it a "natural disaster". But relatives of miners have furiously disputed the description.

The female relative of one missing miner shouted at the Huayuan offices gates, "Who said this is a natural disaster? That's crap. It's totally man-made".

In the weeks before the mine floods, central and provincial safety authorities warned that mines and other employers were not paying enough attention to the threat from flood waters.

The Shandong work safety bureau last month told mines threatened by flooding to stop work, according to a notice on a local coal safety Web site (www.luzhong.sdcoal.gov.cn).