Uttarkashi tunnel collapse: About 67% augur drilling completed, 42 m horizontal pipe drilled through in tunnel

Expediting efforts for safe evacuation of the workers, the Uttarakhand government on Wednesday intensified rescue operations at the Silkyara Tunnel in Uttarkashi where 41 workers remain trapped.

“About 67 per cent augur drilling has been completed to give emergent safe passage to the rescue team and 42 metre horizontal pipe have been drilled through in the tunnel,” according to a government press release.

“The 2 km section of the tunnel, which completed concrete work ensuring the safety of the workers, is the focus of the rescue efforts. In this secured portion of the tunnel, electricity and water supply are operational, and provisions, including cooked food and medicines, are being delivered through additional pipelines of 6-inch diameter in addition to existing 4-inch lifeline,” added the release.

Video communication has been established with the workforce, which further boosted the morale of the trapped workers.

Various government agencies have been mobilised, each assigned specific tasks to ensure the safe evacuation of the workers. National and International tunnel experts are present at site to advise on rescue operation.

Key updates on rescue operations:

NHIDCL Lifeline Efforts:

● The second lifeline for food distribution is functioning efficiently, ensuring an ample food supply like roti, subzi, khichdi, daliya, oranges, bananas in addition to supply of medicines and other essentials like clothes such as T-Shirt, under garments, tooth paste, soap etc.

● Modified communication system with wire connectivity has been developed by NDRF/SDRF through which clear communication is made. People inside reported at morning that they are safe.

● The old lifeline service point/talking point (RHS) has been shifted from the existing point to a safer place and protected.

● To give emergent safe passage to the rescue team, an escape passage by way of box culverts, pipes for a length of 67 meters has been completed.

Horizontal Boring by NHIDCL

● NHIDCL has resumed horizontal boring from the Silkyara end to rescue workers using an Augur boring machine. As on date, 42 meter of pipes has been inserted.
● Fabrication of a protective canopy for the drilling machine is underway.

Vertical Drilling for Rescue by SJVNL
● SJVNL’s machine for the vertical rescue tunnel construction has arrived at the site, and has been installed.

Horizontal Drilling from Barkot Side by THDCL
● THDC has initiated the construction of a rescue tunnel from the Barkot end, with four blasts already completed, resulting in a 9.10 meter drift. Efforts are being made to carry out three blasts per day.

Perpendicular-Horizontal Drilling by RVNL
● Equipments for micro tunnelling required for horizontal drilling to recue labourers has reached site. Additional back up machines are in transit.

Vertical Drilling Toward Barkot End by ONGC
● ONGC is mobilizing machinery from the USA, Mumbai, and Ghaziabad for vertical boring.

Drift Tunnel by Manual-Semi Mechanized Method by Joint Team of THDCL/Army/Coal India and NHIDCL:
● Work is underway to create a drift inside the tunnel, with a safe channel established from 180 meters to 150 meters. The Army is mobilizing box culverts for this purpose. Fabrication of 08 frames has been completed.

Road Cutting and Supportive Work by BRO:
● BRO has completed construction of approach road for vertical drilling by SJVNL and RVNL. BRO is also building approach road for ONGC with geological surveys conducted by ONGC.

On 12 November, a portion of under-construction tunnel collapsed due to debris falling in a 60-meter stretch on the Silkyara side, where 41 workers were trapped.

Five agencies—ONGC, SJVNL, RVNL, NHIDCL, and THDCL— were pressed into service with specific responsibilities, working collaboratively with occasional task adjustments for operational efficiency to rescue workers.

The Silkyara tunnel, about 30 km from the district headquarters of Uttarkashi and a seven-hour drive from the Uttarakhand capital Dehradun, is part of the ambitious Char Dham all-weather road project of the central government.

With inputs from agencies