Uttarkashi: After a three-day halt in rescue operations to bring out the 41 workers trapped in Uttarkashi’s Silkyara tunnel, vertical drilling began Sunday. Clearing a route from the top-down, to the men who have been stuck in the collapsed tunnel since 12 November, is expected to take two days.
At a press conference near the site, Additional secretary, Union Road and Transport ministry and managing director of the National Highways and Infrastructure Development Corporation Limited, Mahmood Ahmed, said, ”Vertical drilling to make an escape passage for 41 workers trapped inside Silkyara tunnel has begun…a total of 86 metres is to be done which is expected to be completed in two days.”
Meanwhile, efforts are on to remove from the rubble parts of the American auger machine engaged in horizontal drilling that broke down Friday. A plasma machine, brought in from Hyderabad, has begun work to remove the auger machine’s broken parts.
Government officials told ThePrint that while the rescue teams managed to remove 20 metres of the broken machine with the help of a gas cutter, the plasma cutter will remove the remaining 25 metre-portion of the blade.
At Sunday’s press conference, secretary and nodal officer for the operation, Neeraj Khairwal, said, “The stuck blade of the auger machine is expected to be cut and taken out tonight or by tomorrow morning.”
Ahmed added, “From tomorrow, we will start working on 2-3 more options. We have asked the SJVNL (Satluj Jal Vidyut Nigam Limited) to do vertical drilling of 1-1.2 meter diameter.” The SJNVL is among the 14 agencies involved in the rescue operation.
Minister of State for Road Transport & Highways, Gen. Vijay Kumar Singh, inspected the vertical drilling site Sunday.
Meanwhile, geologists have called vertical drilling a big risk, rooting for horizontal drilling instead.
Former director of the Geological Survey of India, P.C. Nawani, said to ThePrint, “Vertical drilling will shake the mountain, which will cause vibration and debris can also fall on the (trapped) workers.”
Another geologist, Harsh Vats, agreed: “Vertical drilling could pose a huge threat to the mountains.” As did geologist Y.P. Sundriyal, who told ThePrint, “Vertical drilling can shake the mountain, injuring residents of villages atop the mountain.”
Also read: ‘Building doors’ to pull out Uttarkashi tunnel workers, miracle no one hurt, says Australian expert
Other options
As of now, Ahmed said, there are multiple other options being considered to rescue the workers. While vertical drilling has already started, he said another option is to continue horizontal drilling manually after removing the broken parts of the auger machine. The Indian Army would be helping with manual drilling, he said.
He said the third option is to drill 500 metres, through blasts, from the Barkot end (the other end) of the tunnel. Ahmed said this operation is estimated to take 12-13 days. In the fourth option, parallel horizontal drilling will be done on one side of the tunnel and a survey has been done for the same, he said.
Around 9 metres have already been drilled through blasts on the Barkot end during the early part of the operation.
Meanwhile, the increased water seepage at the entrance of the tunnel since Saturday has also sparked widespread worry though officials said it is commonplace. Explaining the seepage, geologist Sundriyal said, “In the part where the tunnel is being constructed, there are stones such as phyllite rock, flint stone and clay minerals which break and shrink when they come in contact with water.”
(Edited by Smriti Sinha)
Also read: After blocked pipe prevented khichdi from reaching Uttarkashi tunnel workers, hot meals on the way