The Uttarkashi tunnel rescue effort, described by one official as a “warlike” situation, completed its 14th day on Saturday with no drilling on any backup routes initiated yet — and the timeline to free the 41 trapped workers still unclear.

Drilling efforts to reach the workers through a horizontal channel created through the 57m collapsed stretch of the tunnel remained stalled at 49m. Drilling for a backup, 86m vertical channel from the top of the hill downwards is yet to start, officials said.

“The operation is technically becoming more complex…. We’ve never given any timeline for the rescue. We’re working in an environment of unpredictability,” said Syed Ata Hasnain, a member of the National Disaster Management Authority, a Union home ministry agency coordinating the rescue effort.

“We’re in a warlike situation. In a warlike situation we don’t ask when the operation will end.”

Hasnain and another official monitoring the drilling effort said the auger machine had broken with sections of its rotor stuck inside the rubble.

“It has to be cut and removed. The cutting requires sophisticated machinery — the Indian Air Force is now airlifting the machinery,” Hasnain said.

When the auger is removed, further digging through the horizontal channel will be taken up “manually” using power tools, officials said.

While the auger machine was capable of drilling through about 5m of the rubble an hour, the manual digging will slow down the process, the officials said.

Hasnain said vertical drilling from the top of the hill downwards towards the roof of the tunnel was expected to begin within the next 24 to 36 hours.

The Border Roads Organisation has created a road for the drilling equipment to be transported onto the hill from where the vertical drilling will start.

The effort will be to create a 1.2m-wide vertical channel by going through 86m of soil and rock down the mountain to reach the tunnel’s roof. The rescue effort will then needto cut through the roof togain access to the trapped workers.

“This will take some time —we need to have patience to avoid putting pressure on the workforce. The work is dangerous,” Hasnain said, adding that the rescue effort had another backup route on which work might begin soon.

Sanjay Rana, geophysicist and director of Parsan Overseas, a New Delhi-based company that is assisting the rescue effort by providing ground measurement services and a ground-penetrating radar, said a vertical drilling effort could typically cover 86m in two to three days.

Some geologists expressed surprise on Saturday that the rescue effort appeared to be taking up alternative rescue routes in sequence rather than in parallel.

“Vertical drilling is much easier than horizontal drilling — I would have thought the vertical approach was under way in parallel with the horizontal approach,” said Ashish Juneja, professor of geotechnical engineering at IIT Bombay.

But an engineer familiar with the rescue effort told The Telegraph that the vertical approach required a road to be built to transport the drilling equipment to the top of the hill.

“The earthmoving equipment used to build the road was found to be sending vibrations into the hill — so a cautious approach was adopted,” the engineer said.

“We didn’t want anything else to complicate matters. In any case, the horizontal drilling at the time appeared to be proceeding well.”

The road construction was taken up at a slower pace to lower the risk from the vibrations.

An estimated 57m segment of the under-construction tunnel on the highway to Yamunotri collapsed on November 12, trapping 41 workers in a 240m chamber. They are receiving food, water, oxygen and medicines through two narrow supply channels.