Uttarkashi Tunnel Rescue Operation: A Joint Endeavor by ONGC, SJVNL, RVNL, NHIDCL, and THDCL

by Psu Connect
Date: 24-11-23

Several governmental bodies are working round the clock on specific assignments to ensure the safe extraction of the workers.

Uttarkashi Tunnel Rescue Operation: A Joint Endeavor by ONGC, SJVNL, RVNL, NHIDCL, and THDCL

Silkyara Tunnel collapse in Uttarkashi, where 41 workers are trapped, rescue operations are underway with full force and dedication: pti image

In the wake of the Silkyara Tunnel collapse in Uttarkashi, where 41 workers are trapped, rescue operations are underway with full force and dedication. The focus is on a 2 km section of the tunnel featuring completed concrete work that ensures worker safety.

Several governmental bodies are working round the clock on specific assignments to ensure the safe extraction of the workers. Both national and international experts are at the site providing advice on the rescue campaign. Constant communication is being maintained to keep the spirits of the trapped individuals high.

Key Updates on Uttarkashi 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 9th 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