UTTARKASHI/NEW DELHI: Rescue work at the collapsed Silkyara tunnel in Uttarakhand was virtually on hold Sunday as the agencies involved in the effort set themselves up for the next stage - adopting multiple approaches to reach the 41 men trapped inside for a week.

Officials said a road to the top of the hill has been laid in a single day for digging a vertical shaft down into the tunnel. Also, the Tehri Hydroelectric Development Corporation was set to begin “micro tunneling” Sunday night from the Barkot end of the under-construction tunnel on the Char Dham route, part of which collapsed on November 12.

Boring through the debris of the collapsed 60-metre stretch from the Silkyara end was put on hold Friday afternoon when the American-made heavy-duty auger machine encountered a hard obstacle after about 22 metres. This raised fears that the vibrations could pose a danger to the safety of the rescue workers. The setback forced a rethink. Officials drew up a series of alternative plans to reach the workers trapped inside the under-construction tunnel.

After a visit to the site Sunday, Union Road Transport Minister Nitin Gadkari said boring horizontally through the debris with the huge auger machine appeared to be the best bet.

He anticipated a breakthrough in two and a half days.

A media brief issued in Delhi said this drilling would begin again on Monday after safety arrangements for rescue workers are put in place. By Sunday evening, rescue workers had pushed in a six-inch wide tube up to 39 metres into the rubble. Once it cuts across the collapsed stretch, the trapped workers would be sent food and water through this pipe as well.

A smaller four-inch wide “compressor pipe” already runs through the debris and is being used to send in food, water, oxygen and medicines, officials said.

The stretch in which the workers are trapped is about two kilometres of the built-up portion of the tunnel and is 8.5 metres high. There is electricity and water available, a press release said.

The Rail Vikas Nigam Limited has begun work on a vertical pipeline for supplying essential items after the completion of the approach road to the top of the hill.

Road Transport and Highways Secretary Anurag Jain said multivitamins, antidepressants and dry fruit are being provided to the trapped workers. “Fortunately, there is light inside because the electricity is on. There is a pipeline, and so water is available. There is a four-inch pipe that was used for compression. Through it we are sending food from day 1,” he said.

The multiple-pronged approach now being adopted follows a series of setbacks after a portion of the Silkyara-Barkot tunnel collapsed the previous Sunday morning, blocking the way out for the worker who were ending the night shift.

When using earth-moving equipment failed, an auger machine was brought in. When this too didn’t work, the larger American-made drilling machine was airlifted by the IAF from Delhi.

A similar machine was also dispatched from Indore in case a replacement was needed. The vertical drilling equipment arriving next is too big to be hauled by air and will be brought to the site by road, said officials.

After previous efforts failed, boring horizontally through the debris appeared to be the best bet to save lives