Uttarkashi Tunnel Media Brief 24.11.2023 (Updated with site inputs till 1500 hrs)

Continuing their unwavering commitment to saving lives, the government is actively engaged in ongoing rescue operations at the Silkyara Tunnel in Uttarkashi, where 41 workers remain trapped. The 2 km section of the tunnel, with completed concrete work ensuring the safety of the workers, is the focus of the rescue efforts.

Various government agencies are working tirelessly on each assigned specific tasks to ensure the safe evacuation of the workers. National and International experts are present at site to advice on the rescue operation. The government maintains constant communication to boost the morale of those trapped.

Key Updates on Rescue Operations:

1.         NHIDCL Lifeline Efforts:

• Freshly cooked food and fresh fruits are being inserted inside the tunnel at regular intervals using the 2nd life line (150 mm dia) service which has been extended from the initial position to a distance of 12 m to ensure higher stability and safety.

• Consignment consisting of roti, Dal, mixed vegetable and fruits like apples, oranges, bananas etc along with medicines and salts has also been supplied.

• Modified communication system with wire connectivity developed by SDRF is being used for communication regularly. People inside have reported that they are safe.

 

2.Horizontal Boring by NHIDCL

• Auger drilling started at 0045 Hrs on 22.11.2023 was halted due to metallic object (Lattice girder rib) being encountered in front of the pipe and the pipe could not be inserted further. Cutting of Metallic object (Lattice Girder rib) using Gas cutters has been completed. Pushing of 9^th pipe reached an additional 1.8 meter distance. Minor vibration was noted, so Auger was pushed slightly back to re-assess the force to be applied. Obstructions were observed.

• A bent part of forepole (pipe) from tunnel lining was struck in the auger assembly which led to vibrations.

• Strengthening of platform for augur machine using accelerating agent for rapid hardening of concrete is completed.

• Platform for Auger Machine has been strengthened by way of anchoring, bolting, concreting foundation etc.

• Further, auger was required to pull back fully to assess any other damage to pipe. Auger pulling has been completed. GPR (Ground Penetration Radar)  test has been completed. Cutting of bent pipe completed.

• Augur re-assembly work completed and reinserted by 1430 hrs. After placing of Augur 800 mm dia, next pipe fitted with will be placed in position in line with Augur drilling machine.

• Placing, positioning of next pipe is under progress and pushing will commence after completion of welding joints.

 

3.Vertical Drilling for Rescue by SJVNL:

• Drilling Machineries arrived at site. Platform for launching of drilling machine has been completed. Marking of drilling point over the tunnel has been finalized at ch. 300 L/S after discussion with GSI, RVNL & ONGC. Assembly of machine has started.

 

4.   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.

• Shotcreting and rib erection has been completed and additional rib fabrication work is in progress.

 

5.   Perpendicular-Horizontal Drilling by RVNL:

• Equipments for micro tunneling required for horizontal drilling to recue labourers has reached site. Platform likely to be completed by 24.11.2023. Equipment to set up by 25.11.2023.

 

6.   Vertical Drilling (6 inches) by RVNL at Silkyara end:

• Access road of 1150 meter has been completed by BRO and handed over to RVNL. Machine for drilling towed to location by BRO.

• Electric Connection has been provided to RVNL.

• Vertical drilling likely to be completed by 26.11.2023.

 

7.   Vertical Drilling Toward Barkot End by ONGC

• Air drilling Rig machine from Indore has reached site. Submission of report by ONGC to be made after completion of field survey.

8.  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. The Army is mobilizing box culverts for this purpose. 15 numbers of frames have been fabricated.

 

9.   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. 700 meters of approach road has been constructed so far.

 

Background:

On 12th November 2023, a collapse occurred in the under-construction tunnel from Silkyara to Barkot due to debris falling in a 60-meter stretch on the Silkyara side. Immediate mobilization of resources by the State and Central Governments ensued to rescue the 41 trapped labours.

Initially opting for a 900 mm pipe through the debris, safety concerns led to the exploration of multiple rescue options simultaneously. The area of entrapment, measuring 8.5 meters in height and 2 kilometres in length, is the built-up portion of the tunnel, offering safety to the labours with available electricity and water supply.

Five agencies—ONGC, SJVNL, RVNL, NHIDCL, and THDCL—have been assigned specific responsibilities, working collaboratively with occasional task adjustments for operational efficiency.

Note: The timelines provided are subject to change due to technical glitches, the challenging Himalayan terrain, and unforeseen emergencies.