Just over 10 metres of debris remained between the 41 trapped labourers and freedom at Uttarkashi on Thursday evening but an unspecified “hurdle” had temporarily halted drilling.

A rescue official, who didn’t say whether the hurdle was a rock, chunk of concrete or a steel bar in the debris, suggested around 5.30pm that it would take another “four-five hours” to clear.

No one would hazard a timetable for the rescue of the labourers — caged inside a mountain tunnel blocked by landslide-induced debris — having been rendered wiser by previous incorrect predictions about a quick end to the crisis that is now in its 12th day.

Uttarakhand chief minister Pushkar Singh Dhami, who had arrived on the site on Wednesday night in the hope of an imminent rescue, spoke to the labourers through an audio system set up by the National Disaster Response Force (NDRF) to try and boost morale.

An end to the ordeal had seemed near on Wednesday night before the rescuers hit a steel girder at 10pm that took six hours to clear. Two men had to crawl down an 800mm-diameter (32-inch) Hume pipe to reach and cut the girder.

Then the latest “hurdle” slowed the rescuers on Thursday. Currently, a 46.8m escape passage has been created with just 10.2 metres of the 57m-thick wall of debris remaining to be bored through, said Mahmood Ahmed, director-general of the National Highways and Infrastructure Corporation Limited.

“But we’d avoid committing any time limit to reach the trapped labourers, for we don’t know what awaits us in the remaining part of the rubble,” he said.

The drilling is being done through an auger machine pushed into the Hume pipe with a long shaft.

The labourers have been penned in a 240m stretch of the tunnel since 5.30am on November 12, without natural light or enough oxygen, and likely traumatised to various degrees amid the uncertainty and long confinement.

Dhami on Thursday spoke to two of the labourers and posted a video on X.

While the labourers cannot be seen or heard, the chief minister is heard saying in Hindi: “Gabbar Singhji, I am Pushkar Singh Dhami. Ram, Ram. How are you? We have reached very close to you. You have great courage and we all are praying for all of you.... The Prime Minister asks me about you people every day at 7am....”

As Gabbar Singh Negi of Uttarakhand, one of the trapped workers, says something, Dhami asks: “Are you all right?”

He is then heard saying: “No, no, we are praying….”

There’s a pause as Dhami listens to Negi and then says: “There is every arrangement here. We have ambulances here, and hospitals are ready…. Machines have been brought from across the country. Experts including some from abroad have also arrived. We have arranged for helicopters, too, so that we can provide quick medical help if needed.”

Dhami then talks with Saba Ahmad of Bihar. “Saba Bhai, how are you? We have sent your videos to your families…. We know how you and Negiji have been boosting the morale of others. You have kept the entire team united and you all are healthy….”

Girder challenge

Neeraj Khairwal, the nodal officer appointed by the Uttarakhand government to coordinate with all the rescue agencies, said two employees of a Delhi-based private firm had cleared the steel girder before dawn on Thursday after other agencies failed.

“NDRF workers had crawled 45 metres into the Hume pipe and shot a video of the steel girder. Later, two teams were sent to cut it but, after working there briefly, they returned because of the heat and smoke generated when they started cutting the girder,” Khairwal said.

“Then Praveen (Yadav) and Balvindar (Singh) of Trenchless company (Trenchless Engineering Services Private Limited) went inside at 1.30am and cut the girder slowly in the next two-and-a-half hours.”

Contacted, an official with Trenchless told The Telegraph on the condition of anonymity: “We have expertise in making small tunnels, so our technicians know how to clear the hurdles. The government had approached us right at the beginning and we have been providing every support since then.”

Asked around 5.30pm on Thursday how long it would take to clear the latest hurdle, he said: “Our men are working on it. It will take another four-five hours....”

Since it would take over two hours to place the auger drill back into the other end of the Hume pipe — 47 metres from its mouth — drilling may be expected to resume around midnight.

Rescue and trauma

“The NDRF is ready with stretchers fitted with wheels, tied to ropes on both sides. The trapped labourers will lie on a stretcher and be pulled out,” Syed Ata Hasnain, a member of the National Disaster Management Authority, said at a news conference in New Delhi.

“There was an option for them to crawl out but this wouldn’t be advisable, keeping in mind that they may be suffering from claustrophobia because of the long confinement, or may have developed some other mental issues.”

Hasnain added: “There are 41 ambulances on stand-by, one for each worker, in which they and their relatives will be transported to a nearby hospital after an initial check-up. The air force and the state aviation department are prepared to fly those who need special attention to AIIMS Rishikesh.”

All road traffic will be blocked to drive the labourers to Chinyalisour (25km away) and Uttarkashi (45km away), where two hospitals have been prepared for them.

“The post-rescue operation will be another challenge since we have to take the workers to hospital in the minimum time possible,” said Uttarkashi superintendent of police Arpan Yaduvanshi.

Vibration scare

Bhaskar Khulbe, former adviser to Prime Minister Narendra Modi and officer-on-special duty, Uttarakhand tourism department, said some vibration was felt in the tunnel during drilling on Wednesday night.

He said experts from IIT Roorkee had been called to see how this could be minimised and any further collapse during the operation averted.

“Every agency is helping us. The air force provided us with a helicopter last night to bring some (design) experts from Delhi,” Khulbe said.