HANOI, Vietnam (AP) _ Rescuers drilled a hole through a collapsed tunnel in central Vietnam and were communicating with 12 trapped workers who said they were safe, according to an official Wednesday.
The workers became trapped on Tuesday when the tunnel of a hydropower collapsed.
Le Duc Long, a local official in Lam Dong province, said rescuers drilled a tube hole through the 36-meter (118-feet) -long collapsed section of the tunnel Tuesday night, more than 10 hours after the incident, to pump in oxygen and food to the workers.
The workers were able to communicate with the rescuers through the tube, saying they are safe, he said.
"Rescuers are trying their best to get the workers out as soon as possible," Long said by telephone from Lam Dong province. "But we don’t know when we could get them out."
Initial investigation showed that the weak geological structure of the area and rains over the past few days could have caused parts of the tunnel to cave in, he said.
The section that collapsed was some 300 meters (984 feet) from the entrance of the tunnel. The workers were putting concrete on the tunnel’s dome when it tumbled. About 20 of them escaped unhurt.
A private company started construction of the 23-megawatt hydropower plant in 2003, but it has repeatedly faced delays.