Some of the 153 workers trapped in a flooded coal mine in north China's Shanxi Province may still be alive, rescuers said Wednesday, more than 72 hours after the accident.

The trapped miners were working in nine different platforms when the flooding happened, and some of the platforms were above the underground water level, making it possible that some workers might have survived, according to Liu Dezheng, a spokesman of the rescue headquarters and deputy director of the General Office with the Shanxi Provincial Work Safety Committee.

"It is believed that some workers may have a chance of survival. But we are not sure about the figure," he said at a news conference late Wednesday.

"We will go all out to save them. So long as there is a slim hope, we will make 100 percent of effort," he said.

Altogether 261 workers were in the pit of Wangjialing Coal Mine, which was under construction, when underground water gushed in at about 1:40 p.m. Sunday. Although 108 were lifted safely to the ground.

Of the trapped, 81 were from Shanxi, 32 from Henan, and the rest from 10 other provinces.

Currently, more than 1,500 people are participating in the rescue operation, but they have not established contact with the trapped workers.

By 6 p.m. Wednesday, the water level underground had dropped by 18 cm, and a total of 26,000 cubic meters of water had been pumped out of the shaft, Liu said.

Altogether 11 pumps have been used to pump up to 1,125 cubic meters of water per hour, he said.

Rescuers were installing four additional pumps, and it was expected that the pumping capacity could reach 2,035 cubic meters of water per hour Thursday morning, he added.

The mine, which straddles Xiangning County, of Linfen City, and Hejin City, of Yuncheng City, covers about 180 square kilometers.

The mining zone was estimated to have more than 2.3 billion tonnes of coal reserves, including 1.04 billion tonnes of proven reserves, according to the company's official website.

The mine, affiliated with the state-owned Huajin Coking Coal Co. Ltd., is a major project approved by the provincial government. It is expected to produce 6 million tonnes of coal annually once in operation.