Boring to create an escape passage for 41 workers trapped in the Silkyara tunnel for 10 days resumed overnight and there were just 18 metres to go before the drilling machine breaks through the rubble, officials said Wednesday.

Following up on an alternative plan, rescue workers had also dug about eight metres from the other end of the under-construction tunnel on the Char Dham route in Uttarakhand.

At the Silkyara end of the tunnel, the officials said, 800-mm diameter steel pipes have been inserted up to 39 metres through the rubble and in another 18 metres the rescuers would reach the trapped labourers.

NHIDCL MD Mahmood Ahmad told reporters in Silkyara that the stretch between 40 metres and 50 metres is "the most crucial." "After we cross it we can speak with more confidence," he said.

Asked how much more time the operation will take now, he said, "If we don't face any hurdle and go at the same pace we may get some good news late on Wednesday night or Thursday morning." On the alternative plan, Ahmad said, "We are also doing horizontal drilling from Barkot side of the tunnel. Three blastings have been done and we have already entered about eight metres from that end." It will take much longer to reach the trapped workers from the Barkot end, officials had said earlier.

Ahmad said at least three more steel pipes of six-metre length each need to be laid through the rubble to reach the trapped workers from the Silkyara end.

The six-inch diameter food pipline laid on Monday to deliver food and other essentials to the trapped workers had gone from this side of the rubble to the other side after being pushed up to 57 metres, Ahmad said.

Once the drilling is complete, the labourers will have to crawl to safety through the 800-mm diameter steel pipes welded together.

Nodal officer appointed by the state government for the rescue operations Niraj Khairwal said that using the food pipeline which had made communication easier with the trapped workers, the NDRF and SDRF have also established an audio communication channel with them.

"A wire, one microphone and a speaker have been sent to the other side of the rubble and they can be heard better with the help of a headphone on this side. They complained of constipation as they had been consuming food in limited quantities over the past few days. The required medicines have been sent to them. Doctors have talked to them," Khairwal said.

"Mental health issues could also be there in circumstances like this. Psychiatrists will also talk to them," he said.

Other essentials like towels and undergarments have also been supplied to the trapped workers.

Talking to reporters in Silkyara earlier, former advisor to the PMO Bhaskar Khulbe had said, "We have pushed in the pipes up to 39 metres by now. Everything is fine. I have spoken to them (trapped workers). Their morale is high." Asked to spell out a timeline for the evacuation, he said, "We hope to celebrate Bagwal with them", possibly meaning Igas, a festival celebrated in the Garhwal region after Diwali.

This year Igas will be celebrated on Thursday.

The drilling was suspended since Friday when the American auger machine hit a hard object.

NHIDCL officials supervising the rescue operations on the spot had on Tuesday said the auger machine will be put back into operation after the 800-mm diameter steel pipes are pushed through the 900-mm diameter steel pipes already laid through the rubble using the telescopic method.

Prime Minister Narendra Modi spoke to Chief Minister Pushkar Singh Dhami once again on Wednesday morning to take updates on the rescue operations underway at the tunnel and food and other essentials including medicines being supplied to the trapped workers through a new wider pipeline laid for the purpose.

It was through this new pipeline that the first visuals were captured of the trapped workers early on Tuesday with the help of an endoscopic flexi camera sent beyond the rubble.

Dhami briefed the prime minister about the positive progress made over the last 24 hours in the rescue efforts being carried out at the tunnel with coordination between the state government, the central agencies and the international tunnelling experts.

"We are getting continuous guidance from the Prime Minister in this difficult situation. It provides us with a new energy every day to evacuate our trapped brothers safely at the earliest applying all our strength," Dhami said on X.

While drilling and inserting pipe are in progress inside the tunnel, site preparation and machine augmentation for other options such as vertical drilling from top of the tunnel at Silkyara side are also complete.

Meanwhile, state Congress president Karan Mahara and senior party leader Pritam Singh visited Silkyara to review the rescue operations underway.

Talking to reporters at the site, Pritam Singh, who represents the Chakrata constituency in the state assembly, said safety norms were ignored at the time of building the tunnel which has led to a situation like this.

He demanded action against the construction agency for ignoring the safety norms and going ahead with the construction of a long tunnel like this.

On the BJP's charge that the Congress was doing politics over the issue, the two leaders said they gave all their support to the agencies involved in the rescue operations and wish that the 41 labourers come home safe, but if there has been some negligence on part of the government it is their duty as an opposition party to tell the truth to the people.