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 along with medicines and other essentials are being inserted inside the tunnel at regular intervals using the 2nd life line (150 mm dia.) service.
- Video communication has been established by SDRF with standard workforce and direct line communication has been established by NDRF.
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 was resorted to and completed at 0230 Hrs on 23.11.2023. Pushing of 9th pipe was restarted and 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 bend part of forepole (pipe) from tunnel lining was struck in the auger assembly which led to vibrations.
- Strengthening of platform for auger machine was carried out using accelerating agent for rapid hardening of concrete completed followed by anchoring and bolting of the platform.
- Pushing of 10th Pipe ( 4.7 m length) started at 1625 Hrs on 24.11.2023 and a length of 2.2 m was inserted upto 1750 Hrs on 24.11.2023 resulting in total inserted length of 46.9 m.
- During pushing of 10th pipe, further obstruction was observed and pushing of pipe had to stop.
- After visual inspection by welders it was found that the cutter of augur was entangled with lattice girder bars which damaged the 1.9m of length of 800mm passage pipe. Subsequently, manual excavation was started followed by pushing of pipes.
- Total pipe pushing of 58 m has been achieved so far.
- Erection of False Ribs from face of tunnel towards tunnel exit on Silkyara side to protect the Operational area (Ch. 194.50 to Ch. 184.50)-Erection of Ribs started at 1950 Hrs on 25.11.2023. Total 8 number of Ribs erection completed at the time of reporting.
3. Vertical Drilling (1.0m dia) 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.
- Main machine reached at Drilling site. Drilling rig of machine transported from tunnel portal to drilling site.
- Drilling work commenced and at the time of reporting 45 m has been achieved.
4. Horizontal Drilling from Barkot Side by THDCL:
- THDC has initiated the construction of a rescue tunnel from the Barkot end.
- 7th blast has been taken at 0500 Hrs on 28.11.2023.
- Total executed length of drift is 13.20 m. Further, mucking is in progress.
- Fabrication work of 18 number of ribs has been completed.
5. Perpendicular-Horizontal Drilling by RVNL:
- Equipments for micro tunneling required for horizontal drilling to rescue labourers has reached site from Nashik and Delhi.
- The work of making of platform completed. Reinforcement and concreting work under progress.
6. Vertical Drilling (8 inches dia) 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.
- Platform for vertical drilling has been completed.
- Drilling started at 0400 hours on 26.11.2023 and 72 meter completed.
7. Vertical Drilling (24 inches dia) Toward Barkot End by ONGC
- ONGC drilling team visited the site on 20.11.2023.
- Air Drilling Rig from Indore has reached site.
- All the associated material of Air Hammer Drilling Rig mobilized by ONGC are in standby at Rishikesh as the road and location for placement of Rig for drilling are being prepared by BRO.
8. Drift Tunnel by Manual-Semi Mechanized Method by Joint Team of THDCL /Army/Coal India and NHIDCL:
- Drift design completed( 1.2m X 1.5m sections)
- Material available at site.
- Fabrication started on 21.11.2023 by Army welders.
- 22 numbers of frames have been fabricated and completed.
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. 1050 meters of approach road has been constructed so far out of 5000 meters.
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.1