Silkyara Tunnel Collapse: No Early Exit In Sight, As Auger Drill Breaks

The government is actively engaged in ongoing rescue operations at the Silkyara Tunnel in Uttarkashi, where 41 workers remain trapped.

Officials, however, remained non-committal about the timeline for the breakthrough at Silkyara tunnel to rescue 41 trapped workers citing that the situation was getting technically “more complex” after the joints of the auger used for horizontal drilling broke down.

Estimating the time it would take for bringing out the entire auger machine and then carrying out manual excavation, the breakthrough is possible not before late Monday, sources said.

Meanwhile, food, drinks and medical supplies are being given to the workers through the six-inch pipe drilled into the collapsed tunnel. Oxygen is also being supplied through a separate pipe.

Some portion of the auger broke down and now an advanced machine has been airlifted to be pressed into service shortly. Once the broken materials are extracted, the work will resume again, said a member of the National Disaster Management Authority (NDMA).

Most of the trapped workers are migrant labourers from across the country. Many of their families have traveled to the accident site, where they have camped out for days to get updates on the rescue effort and in hopes of seeing their relatives soon.

The rescue team who were trying to reach the trapped workers inside the collapsed tunnel stopped drilling, after their boring machine hit a new metal obstruction in rock debris. So far the rescuers have drilled through 46 metres (151 feet) and needed to excavate up to 12 metres (40 feet) more to create a passageway.    

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.

Asked when the trapped workeers will be able to come out, NDMA Member Lt, General Syed Hasnain said, "We need to have some patience and faith on the workforce deployed for the purpose. The 22.6 metres space is clear and 22.5 metres more need to be cut for which the latest cutting method is required."

He admitted that it was becoming more complex now, as the situation is unpredictable because of the Himalayan zeology.  

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

Freshly cooked food and fresh fruits are being inserted inside the tunnel at regular intervals using the second life line (150 mm diametre) service.

Sufficient fruits, along with medicines and salts has also been supplied in this lifeline in regular interval. Additional dry fruits are also being supplied for future stock.

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

Horizontal Boring by NHIDCL

Auger drilling started on 22 November and was halted due to metallic object being encountered in front of the pipe and the pipe could not be inserted further.

Horizontal Drilling from Barkot Side by THDCL:

THDCL has initiated the construction of a rescue tunnel from the Barkot end, with four blasts already completed, resulting in a 9.10 metre drift.

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

Perpendicular-Horizontal Drilling by RVNL:
Equipments for micro-tunneling required for horizontal drilling has reached site from Nashik and Delhi.

The platform is likely to be completed and equipment is expected to be set up by 27 November.

Border Roads Organisation (BRO) has completed 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. Out of 5,000 metres, 950 metres of approach road has been constructed so far.

On 12 November 2023, 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 the exploration of 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 laborers 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.