JINAN, Jan. 21 (Xinhua) -- Rescuers said Thursday that they are drilling into a heavily blocked shaft to rescue 21 workers trapped in a gold mine in east China, an effort that will take at least 15 days.
Twenty-two miners have been trapped about 600 meters underground since a mine blast on Jan. 10 in Qixia, under the city of Yantai, in Shandong Province.
So far, rescuers have established contact with only 10 of the miners. One is believed to be dead, rescuers said Wednesday.
Rescuers began drilling the shaft with a 711-millimeter diameter bit on Wednesday. By noon on Thursday, they had drilled 18 meters into the shaft.
However, the rescue efforts have been hampered by heavy blockages in the shaft caused by the blast. Experts estimated that a huge blockage, located between 350 and 446 meters into the shaft, measures about 1,300 cubic meters in volume and weighs some 70 tonnes.
Rescuers said Thursday that the workers they are in contact with have been provided with more high-satiety foods, such as porridge and quail eggs, in addition to nutrient solutions. The workers' daily calorific intake has gradually increased from 500 kilocalories in the previous days -- which could only meet the basic needs of survival -- to 2,200 kilocalories.
They have felt generally well after eating these foods, showing a gradual improvement of their physical condition, according to rescuers.
Some of the workers have helped the rescuers search for the other missing miners using laser pointers and loudspeakers, but they have received no response.
Rescuers have continued to lower life detectors and nutrient solutions into other sections of the mine to locate the missing workers, but still have not encountered any signs of life. Enditem