Rescue teams have resumed drilling to reach 41 construction workers who have been trapped in a collapsed tunnel in northern India for nearly two weeks.
A mechanical problem on Thursday had delayed the evacuation effort, officials said.
The platform of the drilling machine became unstable while boring through rock debris, temporarily halting the final phase of digging at the accident site in Uttarakhand state for about 20 hours, state government spokesperson Kirti Panwar said.
Officials could not say how long it would take to complete the drilling and to bring the construction workers out.
They have been trapped since November 12 when a landslide caused a portion of the 2.8-mile tunnel they were building to collapse about 650ft from the entrance.
As the rescue operation stretched into a 13th day, teams had drilled through 151ft and needed to excavate up to 40ft more to create a passageway.
Before the work resumed, rescuers manually dug through debris to remove pieces of metal and prevent further damage, Mr Panwar said.
The rescue teams also are inserting pipes into the dug-out channel and welding them together to serve as a passageway.
About 151ft of pipes have been put in so far, according to Mr Panwar.
Members of the National Disaster Response Force plan to bring the workers out one by one on stretchers that have been fitted with wheels.
Mountainous terrain in the area has proved a challenge for the drilling machine, which broke down last weekend as rescue teams attempted to dig horizontally toward the trapped workers. The machine’s high-intensity vibrations also caused more debris to fall.
The drilling had to stop again on Wednesday after the boring machine hit a metal girder, causing some damage to its blades.
Authorities have supplied the trapped workers with hot meals made of rice and lentils through a six-inch pipe after days in which they survived on dry food sent through a narrower pipe. Oxygen is being supplied through a separate pipe.
Officials earlier released a video from a camera pushed through the pipe that showed the workers in their construction hats moving around the blocked tunnel while communicating with rescuers on walkie-talkies.
The tunnel the workers were building was designed as part of the Chardham all-weather road, which will connect various Hindu pilgrimage sites.
