Some of the 153 workers trapped in a flooded coal mine in North China's Shanxi province may still be alive, rescuers said late on 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 might have survived, said Liu Dezheng, a spokesman with the rescue headquarters.

"We believe that some workers might have a chance of survival. But we are not sure about the figure," he said at a news briefing on Wednesday night.

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

Some 261 workers were in the pit of Wangjialing Coal Mine, which was under construction, when underground water gushed in at about 1:40 pm on Sunday. A total of 108 were lifted safely to the ground.

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

Meanwhile in far northwestern Xinjiang Uygur autonomous region, hopes faded on Thursday with still no sign of the 10 trapped construction workers after a coalmine collapsed on Tuesday despite the continuous efforts of more than 400 rescuers.

Altogether 21 workers were in the shaft when the accident happened at about 10 am at the Shajihai Coal Mine that was under construction in the Mongolian autonomous county of Hoboksar. Eleven were lifted safely to the ground, a local government spokesman said.

"Due to complicated underground conditions, the first two rescue plans failed. The rescuers only managed to dig 2.5 meters into the shaft in three days and the workers were buried somewhere 10 meters deep," a local official told China Daily on Thursday.

The official, who would not be named, said authorities are not optimistic about the chances of survival for the trapped miners, but they will continue their best rescue efforts.

The cause of the collapse is being investigated, he said.

The Shajihai Coal Mine, owned by the Luneng Coal-Electricity Development Co Ltd, is designed with an annual output capacity of 900,000 tons. Construction started in June last year and is expected to be in operation by October next year.