Hundreds of rescuers are make utmost efforts to free the 181 trapped people at two flooded pits in the eastern province of Shandong, local work safety official said on Thursday.

Rescuers began their sixth day at the collieries on Thursday after flood water swept through a 65-meter wide breach in the Wenhe River levee, inundating the Huayuan and Minggong mines, about 150 km south of Shandong's provincial capital Jinan, last Friday afternoon.

By 5:00 PM Thursday, the water level at Huayuan Mine where 172 miners are trapped had fallen by 27.43 meters to 65.17 meters, meaning there was still a 95-meter depth of water to the nearest working site estimated to have trapped miners.

Two more powerful pumps became operational on Thursday, bringing the drainage capacity to more than 2,500 cubic meters per hour, 1,000 cubic meters more than the previous capacity.

A water pump with the capacity of 600 cubic meters per hour, which was put into operation Wednesday afternoon but soon halted due to a broken pipe, resumed pumping around 6:40 AM Thursday, according to the rescue headquarters.

In addition, two of the four drilling sets, called in from the Shengli Oilfield on Monday, began to drill wells to divert water from the flooded shafts. They had dug 119 meters deep, almost one-third of the 385-meter target.

Around 120 cubic meters of water can be pulled out via each well per hour, the headquarters said.

The rescue headquarters are waiting for more powerful drilling machines to speed up the operation.

Another water pump with a capacity of 600 cubic meters per hour has been put into operation late Wednesday night, the rescuers said.

Worth of materials and money donated by governments of cities in Shandong and other places across the country reached a total worth of 7.78 million yuan (about US$1.03 million).

Water resources specialists have blamed the disaster largely on heavy rain and inadequate flood prevention facilities.

Xintai, the city where the two ill-fated mines are located, reported 730 mm of precipitation from Jan. 1 to Aug. 17, according to local meteorological data.

"That's about the same volume of rainfall we had for the whole year," said Yin Changwen, a water conservation expert with the rescue headquarters.

The city's average annual precipitation was 745 mm, he said.

Between 2:00 AM and 3:00 PM last Friday, the Dongzhou Reservoir on the upper reaches of the Weishui River, a tributary of the swollen Wenhe River, received 161 mm of rainfall, the biggest rain volume in 70 years, said Yin.

"The torrent from upstream poured down into the Wenhe River at 1,800 cubic meters per second, and instantly tore a breach in the levee," he said.

Before the breach was blocked early on Sunday to pave way for the rescue operation, an estimated 12.6 million cubic meters of water had poured down the two adjacent pits.

(Xinhua News Agency August 24, 2007)