The rescue operation to save the 41 workers still trapped in a collapsed tunnel in Uttarakhand's Silkyara is expected to continue on Friday, as the drilling work was halted after technical snag in the Auger drilling machine on Thursday.

This comes just hours after drilling to evacuate 41 trapped workers resumed, following a six-hour setback Wednesday night as the American machine encountered an iron girdle.

International expert Arnold Dix on Thursday evening informed about “some difficulties” with the Auger machine but did not elaborate on the nature of “difficulties”, and it was not immediately clear that this will lead to any major delay in the rescue operation that has entered its 13th day.

Meanwhile, National Disaster Management Authority (NDMA) member Lt Gen (retd) Syed Ata Hasnain said that workers trapped inside are safe, and there is no shortage of light or oxygen.

Uttarakhand Chief Minister Pushkar Singh Dhami visited the Silkyara Tunnel in Uttarkashi, where he spoke to the workers. In an official statement on Thursday, the Chief Minister’s Office revealed that CM Dhami, during his visit, spoke with trapped workers Gabbar Singh Negi and Saba Ahmed, inquiring about their health and updating them on the ongoing rescue efforts.

The workers, in their conversation with CM Dhami, assured him that all other workers in the tunnel were safe and in good health. Dhami conveyed to them that Prime Minister Narendra Modi is actively monitoring the situation and the progress of the rescue operations.

However, experts have shared their disappointment with the whole operation. “The Chief Minister is repeating the same words, but the workers are still trapped,” an Uttarakhand based expert said. According to SMA Kazmi, a senior journalist from Uttarakhand, the rescue operation will continue on Friday and will be finished soon.

“The issue is that a lot of debris is filled inside the tunnel. The only silver lining is that the tunnel is 2 km long due to which the workers are able to breathe and food the authorities are able to send food through the pipes,” he said.

Kazmi also said that a pipe has been installed that would help in rescuing the workers but the last 12 metres are getting difficult due to steel materials that are stuck. “It is there that the officials are trying to figure out their next move,” he said.

Former advisor to the Prime Minister’s Office, Bhaskar Khulbe, present at the site, noted the removal of steel obstructing the pipe’s movement, indicating progress in the operation. According to a state government official, the rescue operation is in its final stages, and the trapped workers are expected to be pulled out soon.

Earlier, NDRF Director General Atul Karwal, had said that the 41 workers will be pulled out on wheeled stretchers one by one through a big pipe that is still being drilled to reach them. The rescuers had also considered the option of making the workers crawl out one by one. Their health condition, however, may prevent them from crawling out on their own, following 12 days of living under the debris of the tunnel without any natural light and full meals, though they have been given supplies via small "lifeline" pipes.

The NDRF personnel will slide in through the pipe and once they reach the workers, they will use the stretchers to send out workers one by one, Mr Karwal said, according to PTI. Every worker will be made to lie low on the stretcher to prevent their limbs from scrapping the welded pipe's metal underside while NDRF personnel pull the stretcher with a rope, officials said.

The workers were trapped inside the tunnel after an iron mesh that had come in the path of the auger machine drilling an escape path was removed. The rescue operation has been underway since November 12.