Rescuers will take at least 15 more days to get through a massive amount of debris and reach miners already trapped for 11 days since an explosion in a goldmine in eastern China, authorities say.
The mine shaft is blocked 350 metres below the surface by 70 tonnes of debris that extends down another 100m, the Yantai city government said on its social media account on Thursday.
"Based on expert evaluations, the extent of the blockage ... is well is out of expectation," it said.
One worker has died from head injuries in the explosion, state media said earlier on Thursday. Of the remaining 21, rescuers have established contact with 10, one is reportedly alive in a nearby chamber, and the status of the other 10 is unknown.
The dead worker had been in a coma. Two others are said to be in poor health. Rescuers have delivered food, medicine and other supplies to the group of 11 as they work to remove debris and improve ventilation.
The state media reports said exhaustion has set in among some of the workers since the January 10 explosion ripped through the mine that was under construction in Qixia in Shandong province.
Rescuers were attempting to clear cages and other debris blocking the main shaft while drilling other shafts for communication, ventilation and possibly to lift workers to the surface. Boring has reached depths of about 700m.
Mine managers have been detained for waiting more than 24 hours before reporting the accident, the cause of which has not been announced.
Australian Associated Press