Members of a rescue team work at the site of a gold mine explosion where 22 miners are trapped underground in Qixia, in eastern China's Shandong province, on January 20, 2021.
CNN  — 

Chinese officials say it could day 15 days to drill through 70 tons of debris to reach miners trapped underground for nearly two weeks after an explosion at a gold mine in eastern China.

Twenty-two miners were left trapped at least 600 meters (2,000 feet) underground following the blast on January 10 in the city of Qixia in Shandong Province. Eleven miners were confirmed to be alive on Sunday after rescue workers were able to drill a channel into a section the mine and install a telephone line, according to Chinese state news agency Xinhua.

One miner is believed to be dead after sustaining a head injury in the explosion, state media said. Ten people are stuck in a chamber of the gold mine 600 meters (2,000 feet) from the entrance and are in contact with rescue teams. One miner is believed to be trapped in another section, while the fate and whereabouts of 10 others is unknown.

Efforts have been underway to reach the workers since the blast occurred about 240 meters (800 feet) from the mine’s entrance. Food, medical supplies, blankets, and batches of nutrient solution have been passed down a shaft to the 10 workers, who have shown a “gradual improvement” in their physical condition, according to rescue workers cited by Xinhua.

According to state media, rescue teams are hoping to pull the miners out through a 711-millimeter (28-inch) diameter passage. By noon Thursday, rescuers had drilled 18 meters (59 feet) into the mineshaft but heavy debris could slow efforts.

Gong Haitao, deputy head of Yantai’s publicity department, said at a press conference Thursday the mineshaft is blocked 350 to 446 meters (1,100 to 1,400 feet) below the surface by 70 tons of debris.

“Although the efficiency (of the rescue work) has improved since the 20th, it will take at least 15 days to clear the rescue channel in the main shaft due to the voluminous size of the obstacles,” Gong said.

The miners have already been trapped underground for 12 days.

Gong added that rescuers are trying various different ways to clear the obstacles, including the use of high powered machinery and deploying more rescue workers.

Rescue teams work to drill through debris to reach the 22 trapped gold miners, on January 20, 2021.

Concern has been growing for the uncontacted miners. Some of the workers in the chamber are trying to help rescuers locate their missing colleagues by using laser pointers and loudspeakers, but they have received no response, Xinhua reported.

Rescuers have also drilled smaller channels into other sections of the mine and are lowering nutrient solutions and other means to detect breathing or movement, but no signs of life have been encountered.

Rescue workers are reported to have first heard knocking sounds from those trapped on January 17, followed by pulling on iron ropes. On Monday, miners were able to get a note to rescuers. Xinhua quoted the note as saying: “We are heavily exhausted and in urgent need of stomach medicine, painkillers, medical tape, external anti-inflammatory drugs, and three people have high blood pressure.”

Chinese state media said it could take 15 days to reach the miners trapped 600 meters underground.

Explosions and deaths are not uncommon in Chinese mines. In September, at least 16 workers in southwestern China died after they became trapped underground in a coal mine and exposed to unsafe levels of carbon monoxide, state media reported.

And in 2016, dozens of workers were confirmed dead after a gas explosion at a coal mine in the city of Chongqing.