No additional survivors were found after rescuers managed to bore a hole 220 meters into a collapsed gypsum mine in Pingyi, Shandong province, on Monday, according to the on-site rescue command center.
Equipment that can detect life, including video and audio gear, was lowered into the mine through the hole, but the search came up empty.
Video showed water more than one meter deep.
Rescuers sent bottles of liquid nutrients through the hole, hoping the bottles might reach trapped miners.
Four trapped miners were detected alive on Dec 30 about 50 meters east and were awaiting rescue. Rescuers sent them food, drinks, clothes, medicine and lamps.
The collapse trapped 29 miners working underground on Dec 25. Eleven escaped or were rescued, one was confirmed dead and 13 others are listed as missing.
Rescuers continue to dig holes to reach the four trapped miners, but progress is slow because of complex geology. Du Bingjian at the command center said tunneling increased the risk of new cave-ins, and teams have been forced to change their approach due to complicated underground conditions. It is hard to say when a rescue tunnel will reach the four, Du said.
Cheng Zhenqian, a medical expert at the command center, said the four are in stable condition and are getting regular food. Psychological therapists talk to them by phone every day to encourage them to hold on.
About 1,000 people are involved in the rescue effort.
The command center also sent people to check the condition of houses and roads around the collapsed mine. To date, three families moved out of their houses, whose bases were left hanging when the surface ground subsided.
The owner of the mine appeared to have committed suicide by jumping into deep water and drowning two days after the accident.
The cause of the collapse is yet to be determined.
