Rescuers found 11 of the survivors on Tuesday and spoke to them via a waterproof telephone delivered underground, the official provincial newspaper Qilu Daily said on Wednesday.
Song Xicheng, the medical rescue team leader, told reporters that more than 80 medical personnel were on standby, including nutritionists, neurosurgeons, trauma specialists and psychologists.
Newly drilled channels have enabled the teams to deliver food, medicine and blankets, improve ventilation, and drain away water before they begin the extraction effort.
Eight of the 11 miners reached on Tuesday were in good health, two were unwell and one was in a coma after being struck in the head during the explosion, the Qilu Daily said, citing the headquarters of the rescue teams.
The 12th surviving miner is in another section and is believed to be injured, though the situation remains unclear.
The handling of the accident by local authorities has been criticised by state media, and two senior officials have been dismissed.