Uttarkashi: After rescue operations to extract 41 workers trapped within a collapsed tunnel in Uttarakhand’s Uttarkashi district came to a standstill over the weekend following the breakdown of an American drilling machine, it was decided that a different strategy would be employed — drilling from the top down.
While waiting for the replacement being airlifted from Indore, a team comprising officials from the Prime Minister’s Office (PMO) at the site and experts came to the conclusion that the vibrations from the heavy-duty auger inside the tunnel were causing more debris to fall, posing a risk to the lives of the rescue personnel. Alternative options were explored by the team, one of which included vertical drilling at multiple spots across the tunnel.
By Saturday evening, the Border Road Organisation (BRO) and the Rail Vikas Nigam Limited (RVNL) were collaborating on working out how to transport vertical drilling machines to the top of the debris mountain that is weighing down the tunnel, with the help of the Indian Army’s construction team.
Three augers meant for vertical drilling, weighing around 75 tonnes each, are being brought in from Gujarat and Odisha via railways (as air transportation was not feasible). It was yet to arrive on site, as of Monday, ThePrint has learnt.
According to details provided to ThePrint by the BRO team on-site, temporary roads are being constructed on both sides of the debris mountain to facilitate the transportation of the augers.
Workers engaged in building the tunnel, along with those from then BERNARD Gruppe — the European company that provided design services to Navayuga Engineering Company Ltd building the Silkyara-Barkot tunnel — are working towards building the temporary roads.
Meanwhile, an Australian tunnelling expert, Professor Arnold Dix, arrived Sunday to lend his expertise to the rescue operations. Speaking to ANI, the President of the International Tunneling and Underground Space Association, said: “Great work is being done. This is going to happen and we are on it. The whole team is here. We are going to find a solution and get them out.”
Union Road Transport and Highways Minister Nitin Gadkari, along with Uttarakhand Chief Minister Pushkar Singh Dhami, arrived at the site Sunday. After assessing the ongoing rescue operations, they informed reporters that, given the current situation, it is imperative to conduct vertical drilling through the debris using an American auger machine in the tunnel since this method is deemed the fastest way to reach the stranded workers.
A similar strategy was reportedly employed in 2015 in Himachal Pradesh. In Bilaspur, three workers were trapped for nine days after an under-construction tunnel caved in 80 metres from the opening. The workers were eventually pulled out successfully through a passage created via vertical drilling.
In the press briefing following the meeting, Gadkari said, “If the auger machine works properly, we will be able to reach them (victims) in the next two to two and a half days.”
However, Bhaskar Khulbe, former advisor to the PMO, has stated that the operation may take another four to five days to complete.
Post the drilling by the RVNL, the rescue of the workers will be handled by the National Disaster Response Force (NDRF), and the process is likely to take three to four days, sources told ThePrint Sunday.
Speaking to the media, road, transport and highways secretary Anurag Jain said that while the BRO focuses on constructing the temporary road, the RVNL has successfully installed another pipeline to supply essential commodities.
Until now, a small four-inch pipe was being used for delivery of food, water, oxygen, and medicines. After days of just dry fruits, the trapped men had requested cooked food to sustain themselves. For this, the RVNL installed a 60-inch-wide, 39 metres long tube for transmission of cooked food and water. The first batch of cooked food — a simple meal of rice and daal — and water was sent inside Monday, along with a camera.
Also read: Uttarkashi rescue work: 2nd pipe installed to deliver food & medicines, ‘6 plans in progress’
What happened
On 12 November, a 30-metre section of the under-construction Silkyara Tunnel (or the Silkyara-Barkot tunnel) collapsed, trapping 41 men in a 2 to 2.5 km buffer zone within.
The tunnel is part of the central government’s ambitious Char Dham all-weather road project. Being built at an estimated cost of around Rs 12,000 crore by Navayuga on behalf of the National Highways and Infrastructure Development Corporation Limited (NHIDCL), it aims to reduce the distance from Uttarkashi to Yamunotri by approximately 25 km.
Over the past eight days, rescue efforts have hit one snag after another. A specialised auger machine imported from the US — and airlifted from Delhi after the first auger broke down Tuesday — was being used to drill a path to the trapped men, but that too broke down Friday. Drilling work began again Saturday evening after a third auger machine reached the site from Indore but work has now halted in order to plan vertical drilling.
While arrangements for vertical drilling are made, the Tehri Hydropower Development Corporation (THDC), along with RVNL, is set to commence ‘micro tunneling’ work from the Barkot end, with heavy machinery already mobilised for the task.
The necessary equipment has been transported to the site. Oil and Natural Gas Corporation (ONGC), with expertise in deep drilling, has initiated preliminary work on vertical drilling from the Barkot end.
Uttarakhand Disaster Management Secretary Ranjit Kumar Sinha said, “We will be working on the remaining 400-metre part of the tunnel.” The THDC, he said, will “construct a 2-2.5-metre-diametre vertical tunnel so that people can be rescued”.
“Moreover, we will do vertical drilling and make a bore so that we can rescue people. If the bore’s diameter is sufficient or we can at least send life support,” he added.
(Edited by Zinnia Ray Chaudhuri)