Tunnel Escape Plan: Workers To Squeeze Through Pipes Less Than 3-Foot Wide

Five days after an under-construction tunnel collapsed in Uttarakhand and trapped 40 labourers, a piece of special machine has been flown to the spot to expedite the rescue work, Atul Karwal, the chief of National Disaster Relief Force, told NDTV during an exclusive interview. He said they are "hopeful" that the labourers could be brought to safety within "12 to 15 hours".

The American Auger drill is expected to cut through 70 metres of rock -- much of which came down from the roof during the rescue efforts -- in an approximate 12 to 15 hours. The machine works at a "theoretical speed" of 5 metres an hour.

The authorities are planning to bore through the rock and insert an 80 cm (less than 3 feet) through which the labourers can crawl through.  In case anyone is incapacitated or injured, "we can use stretchers and harnesses to bring them out," Mr Karwal told NDTV.

The rescue work that started on Sunday after a section of the tunnel roof collapsed, suffered several setbacks due to rock fall. The last few have increased the length of the blocked portion from an initial 40 to 50 metres to an approximate length of 70 metres.  

"The American Augur machine is at work and as per the last update, the first length of the pipe has been inserted through the ruble and the they are welding the second section. At a theoretical speed of 5 metres an hour, we should be able to do it in the next 12 to 15 hours," he said. He however, added that the situation at the spot is completely "unpredictable".  

"We might find some obstruction in the path," he said citing as examples iron rods from the roof that were already touching the rubble or more rock falls from the roof.  

The rescuers have already spoken to the team that managed to rescue 12 teens in Thailand's Chiang Rai province. The junior footballers and their coach got trapped in Tham Luang Nang Non, an under-water cave system in Chiang Rai province.

Suggestions are also being taken from the Norwegian Geotechnical Institute on how to carry out operations inside the tunnel.  

The 4.5-km tunnel on the Brahmakhal-Yamunotri National Highway, which will join Silkyara and Dandalgaon in Uttarkashi, is part of the Chardham project. Once finished, it is expected to cut down the distance by 26 km.