Uttarakhand Tunnel Collapse: Joint Rescue Operations By NHIDCL, SJVNL, RVNL, ONGC, THDCL Continue On War Footing

Arun Kumar Das

Nov 24, 2023, 07:21 AM | Updated 10:15 AM IST

Ongoing tunnel rescue operations, Uttarakhand.
Ongoing tunnel rescue operations, Uttarakhand.

Continuing the unwavering commitment to saving lives, multiple government agencies are working on a war footing to expedite the ongoing rescue operations at the Silkyara Tunnel in Uttarkashi, where 41 workers remain trapped. 

The 2 km section of the tunnel, which is the focus of the rescue efforts, has been wholly concretised to ensure the safety of the workers,

In this secured portion of the tunnel, electricity and water supply are operational, and provisions, including food and medicines, are being delivered through a dedicated 4-inch compressor pipeline.

Various government agencies have been mobilised, each assigned specific tasks to ensure the safe evacuation of the workers. The government maintains constant communication to boost the morale of those trapped.

The boring operation to create an escape passage for the trapped workers resumed last night (24 November), with rescuers successfully placing broad pipes up to a depth of 45 metres through the debris.

Rescuers have to drill up to around 57 metres to reach the trapped workers stranded on the other side of the rubble.

According to officials, 800-diameter steel pipes have been inserted up to 39 metres through the rubble.

The drilling was suspended earlier after the auger machine hit a hard object. The resumption of drilling with the auger machine is expected to expedite the rescue efforts.

Elaborate healthcare arrangements have been established for the workers as and when they crawl through the pipe.

This came after a six-inch diameter food pipeline laid on Monday (20 November) to deliver food and other essentials to the trapped workers had gone from this side of the rubble to the other side, after being pushed up to 57 metres.

Earlier in the day, Prime Minister Narendra Modi spoke to Chief Minister Pushkar Singh Dhami to take stock of the ongoing rescue operations at the tunnel.

Prime Minister Modi inquired about the food, essentials, and medicine supplied to the trapped workers through a new and wider pipeline laid for the purpose. Through this new pipeline and an endoscopic flexi camera sent beyond the rubble, the first visuals of the trapped workers were captured on Tuesday (21 November).

National Highways and Infrastructure Development Corporation Limited (NHIDCL) Lifeline Efforts   

A significant breakthrough was achieved on 20 November as NHIDCL completed drilling an additional lifeline — a 6-inch diameter pipeline — to supply essential items.

Freshly cooked food and fresh fruits are being inserted inside the tunnel regularly using the second lifeline service (150 mm diameter food pipe). It has been extended from the initial position to a distance of 12 metre to ensure higher stability and safety.

State Disaster Response Force has established video communication with the stranded workforce. The National Disaster Response Force has also established a direct communication line-connection.

Using an Augur boring machine, NHIDCL has resumed horizontal boring from the Silkyara end to rescue workers. Auger drilling started at 12.45 am on 22 November 2023. A metallic object (Lattice girder rib) was encountered in the front of the pipe, and the pipe could not be inserted further. 

The cutting of the metallic object (lattice girder rib) using gas cutters was completed at 2.30 pm. The trenchless team entered the pipe manually twice to confirm the clearance of the rescue pipe. Pushing of the ninth pipe started at 1.10 pm and reached an additional 1.8 metre. Minor vibration was noted, so Auger is being pushed slightly back to re-assess the force to be applied. Augering will start shortly after that.

Fabrication of a protective canopy for the drilling machine is also underway.

SJVNL's machine for the vertical rescue tunnel construction has arrived at the site and has been installed. Drilling was expected to start by the evening of Wednesday (22 November).

THDC has initiated the construction of a rescue tunnel from the Barkot end, with four blasts already completed, resulting in a 9.10-metre drift. Efforts are being made to carry out three explosions per day. Drilling for rock bolts and rib erection work in the portal area is in progress.

Perpendicular-Horizontal Drilling By Rail Vikas Nigam Limited (RVNL)

Equipment for micro tunnelling required for horizontal drilling, to rescue labourers, has reached the site. The platform is expected to be completed by 24 November, and equipment will be set up by 25 November.

Vertical Drilling Toward Barkot End By ONGC

Air-drilling rig machine from Indore has reached the site. The submission of the report by ONGC is to be made after the completion of the field survey. 

Work is underway to create a drift inside the tunnel. The Army is mobilising box culverts for this purpose. Fabrication of frames has started.

Road Cutting And Supportive Work By Border Roads Organisation (BRO):

BRO has completed the construction of an approach road for vertical drilling by SJVNL and RVNL. BRO is also building an approach road for ONGC, with geological surveys conducted by ONGC. BRO has made an access road of 300 metres.

On 12 November, a collapse occurred in the under-construction tunnel from Silkyara to Barkot due to debris falling in a 60-metre stretch on the Silkyara side. Immediate mobilisation of resources by the state and central governments ensued to rescue the 41 trapped labourers.

Initially opting for a 900 mm pipe through the debris, safety concerns led to exploring multiple rescue options simultaneously. The area of entrapment, measuring 8.5 metres in height and 2 kilometres in length, is the built-up portion of the tunnel, offering safety to the labourers 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.

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