Rescuers at the under-construction tunnel collapse site in Uttarkashi on Tuesday initiated the process of inserting large-diameter mild steel pipes through the rubble using an auger machine to rescue the 40 workers trapped for two days now, officials said.
The pipes will be pushed in using the horizontal drilling equipment to create an escape passage for the workers, who are safe and are being provided with oxygen, water and light food items such as dry fruits, they said.
Disaster Management Secretary Ranjit Kumar Sinha said authorities have set a target of rescuing the trapped labourers by Tuesday night or Wednesday.
The officials said a part of the tunnel being built between Silkyara and Dandalgaon on the Brahmakhal-Yamunotri National Highway caved in on Sunday morning following a landslide.
They said that the mild steel (MS) pipes and the auger machine arrived at the spot in the early hours of Tuesday.
A platform is being prepared for the auger drilling machine, the officials said, adding that the MS pipes have a diameter of 900 mm.
Contact is being maintained with the trapped labourers and the assurance that a huge rescue operation is being carried out by various agencies to evacuate them has also boosted their morale, NHIDCL Executive Director Colonel Sandip Sudehra (retired) said.
The National Highways & Infrastructure Development Corporation Limited (NHIDCL) is the agency engaged in building the tunnel.
Uttarkashi's Chief Medical Officer R C S Panwar said a six-bed temporary hospital has been set up near the tunnel and 10 ambulances with medical teams stationed to provide immediate medical care to the trapped workers after their evacuation.
According to a list of the trapped workers issued by the District Emergency Operation Centre, 15 are from Jharkhand, eight from Uttar Pradesh, five from Odisha, four from Bihar, three from West Bengal, two each from Uttarakhand and Assam, and one from Himachal Pradesh.