Rescuers drill vertically as part of tunnel rescue

Rescuers managed to vertically drill through nearly 20 metres down the hill above the Silkyara-Barkot tunnel on Sunday, the first day of the new approach being adopted to reach the 41 workers trapped inside for 14 days, even as officials started work on two or three more options as anxiety mounted over the well-being of the trapped men.

- Amit Bathla

In their new vertical approach, rescue workers have to drill down 86 metres to reach the tunnel, and by evening, the Satluj Jal Vidyut Nigam Limited (SJVNL) had bored down to about 19.5 metres. At this rate, if there are no other obstacles, the rescuers should be able to reach the workers by Thursday in an operation that has already dragged on much longer than was previously expected.

"SJVNL is drilling a 1.2 metre diameter hole vertically for evacuation of the trapped men.

We identified spots where the drilling could be better... We think that this will complete in 100 hours (the next four days) if there is no obstacle. One drilling rig can only drill for 45 metres. We will have to change the rig," Mahmood Ahmad, additional secretary, ministry of road transport and highways of India, and managing director of National Highways & Infrastructure Development Corporation Limited (NHIDCL), said.

As the drilling progresses, 700mm wide pipes are being inserted to create an escape passage. A little distance away, a thinner, 200mm probe is being pushed in. It has reached the 70-metre mark.

The latest approach, however, may bring up its own complications.

Drilling from the top of the hill may impact the stability of the tunnel, which was still being constructed, officials said.

"Drilling from the hilltop may impact the stability of the tunnel. There is a risk of tunnel collapse or further structural damage, especially if the construction of the tunnel was not completed or if the tunnel is  not adequately supported...

maintaining communication between the drilling team and the trapped workers inside the tunnel is crucial," an official from the Rail Vikas Nigam Limited (RVNL) said requesting anonymity.

The under-construction 4.5-km tunnel in Uttarakhand caved in early on November 12.