JINAN -- Rescuers are expected to enter a flooded iron ore mine in East China's Shandong province Wednesday afternoon as drainage sped up three days after flood water trapped 24 workers underground.

The water level in the shaft was reduced to 27.8 meters under sea level by 10 am, still 2.2 meters above the platform where the workers were believed to be stranded, the emergency rescue headquarters said in a press release.

Rescuers would hopefully enter the pit for search and rescue in three hours, it said.

Four pumps were working at the scene and had drained nearly 10,000 cubic meters of sludge from the shaft. Two more were being installed to speed up the drainage.

Meanwhile, nearly 100 excavators and bulldozers were stuffing a puddle on the ground, from which flood water was believed to have gushed and drowned the pit of Zhengdong Mining Co. in the Fangzi District of Weifang City at around 11 pm Sunday.

The city government said 31 people were working underground and seven escaped.

Mine authorities said the workers were conducting maintenance in the pit when the accident occurred.

The mine, with a designed annual output of 100,000 tonnes, received a production permit in February 2009, and operation had been planned to begin this October.