LIVE | Silkyara tunnel collapse: Vertical drilling likely to be completed by Nov 30, says NHIDCL
Tunnelling expert Chris Cooper said all the debris from the auger machine has been removed and manual drilling will start in a few hours
National Highways and Infrastructure Development Corporation Limited (NHIDCL) Managing Director Mahmood Ahmad on Monday (November 27) said the work of the vertical drilling at Uttarkashi tunnel where 41 workers remained trapped will be completed by November 30.
Addressing a press conference in Uttarkashi, Mahmood Ahmad said, “We have completed around 30 meters of drilling. The current machine that has been deployed can drill around 40-45 meters. We have brought two more machines for this purpose. SJVNL has brought those machines. Changeover machines will take time. We are expecting vertical drilling work would be completed by November 30.”
Meanwhile, Neeraj Khairwal, secretary, Uttarakhand government, said that the principal secretary to PMO, PK Mishra, instructed that the health of the trapped workers should be monitored from time to time. “The principal secretary said that the safety and security of these workers are important. He said that care should be taken of people stranded inside. Their health should be monitored,” he said.
Earlier, a delegation led by Mishra took stock of ongoing efforts to rescue 41 trapped workers in the Silkyara tunnel in Uttarkashi on the 16th day of the operations. Union Home Secretary Ajay Kumar Bhalla and Uttarakhand Chief Secretary SS Sandhu accompanied him while taking stock of the ongoing rescue work. The principal secretary also enquired about the food items sent to the workers trapped inside the tunnel. He also spoke to them and their families.
In another significant development, micro tunnelling expert Chris Cooper said on Monday that all the debris from the auger machine has been removed and manual drilling to reach the trapped labourers will start in a few hours.
The remaining parts of the auger machine stuck in the rubble inside the Silkyara tunnel, where 41 labourers have been stranded for the past 15 days, were removed early on Monday. The auger drill got stuck last Friday, forcing officials to give up on the 25-tonne machine. Parts of the auger were left to be removed from an 8.15-metre area on Sunday night. It was necessary to extract the shaft and fins of the machine from the rubble completely to pave the way for manual drilling and pushing of pipes, which is in the final stretch with around 12 metres more to go.
(With agency inputs)
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- 27 Nov 2023 8:29 AM GMT
31 metres of vertical drilling done
Vertical drilling from above the Silkyara-Barkot tunnel has been done up to 31 metres, former BRO DG Harpal Singh said on Monday at the site of the rescue operation.
A total of 86 metres has to be drilled vertically to prepare an escape passage for the 41 workers trapped for the last 15 days. Pipes of 1.2 metres in diameter have to be laid vertically through the top of the tunnel by this method adopted as a second option.
Preparations are also underway to start horizontal drilling inside the main tunnel manually, he said. Rescuers need to manually dig 10 to 12 metres through the rubble after the auger machine broke down.
“Frames of 800-mm diameter pipes have been prepared. We will move ahead by half a metre to one metre gradually. If all goes well and no obstacles are encountered a 10-metre stretch can be covered in 24-36 hours,” he said. (PTI) - 27 Nov 2023 6:13 AM GMT
Ground report | Vertical drilling is tough, needs to be done with extreme care
Now that Plan B of the rescue mission is in place, 30 metres of the total 86 m have been dug vertically, said Niranjan, Puthiya Thalaimurai correspondent who is covering the rescue operation from Uttarakhand.
The first 10-15 m were relatively easy since rains had softened the top layers of rocks to a certain extent. The harder rocks in the inner layers may pose a larger challenge. "The drilling cannot be done hastily, since the safety and welfare of the rescue team is also involved," he pointed out.
He further said vertical drilling is a lot more difficult than horizontal. The team is looking at 2-3 ways to make inroads, including tiny detonators that will aid the digging without causing harm. Use of chemicals is also being considered.
"By evening or night we will get a better picture of when the rescue operation can be completed," he said.
