Uttarkashi tunnel collapse: How rescue op has progressed so far; what next?

It has been more than 160 hours since 41 workers got trapped in the 4.5-km Silkyara tunnel in Uttarakhand but it seems they will still have to wait a little longer for their ordeal to end. The under-construction tunnel collapsed on November 12 morning with the labourers drawn from several states inside it.

An American auger drilling machine was flown from Delhi to the tunnel on Wednesday night (November 15) to speed up rescue efforts as the earlier one deployed for the purpose could penetrate only up to 45 metres of rubble. It had to be replaced by a heavier and more efficient drilling machine as the debris had spread over an area of about 70 metres due to constantly falling rubble from above.

After five days of a concerted effort to rescue these labourers, the drilling work was halted on Friday (November 17) as the machine hit a metal part in the debris. Rescue workers had by Friday drilled up to 22 metres through the rubble, inching closer to the trapped workers. The rescue team needed to drill up to 60 metres to insert 800 mm and 900 mm diameter pipes – one after the other -- with the help of a giant drill machine till an escape passage was created for the labourers stuck behind the collapsed portion of the under-construction tunnel.

What has been done till now to rescue them?

Two rescue bids failed in the first four days of operations. At first, rescuers tried to dig through the rubble using heavy excavator machines, but loose rock and sand collapsing from the roof of the tunnel hampered progress.

Subsequently, they tried to drill a hole using an auger machine and fitting large pipes. But the attempt was stymied when the machine suffered damages after hitting a boulder.

Around 10.30 am on Thursday, the third attempt began with an auger machine flown in from Delhi. While the first auger machine with 35 HP had the capacity of drilling 1 metre per hour, the new 175-200 HP machine could cut through rock at 5 metres an hour. The machine began drilling through the rubble, which had increased to 70 metres from the initial 40, on Thursday but stopped work on Friday evening after a ‘cracking sound’ was heard.

What’s the condition of the trapped workers?

Anxious families waiting outside for a week are losing patience and getting desperate as all attempts to drill a pipe into a collapsed tunnel have failed so far.

Kin of these workers are venting their ire against the government and the company that was building the tunnel on the Char Dham route. They said the voices of the labourers inside were getting weaker, their strength seemingly dimming and they were also not getting enough food. “Neither the company nor the government is doing anything,” they lamented while alleging that those trapped are also short of food and water.

However, the authorities on Sunday said they are providing multi-vitamins, anti-depressants and dry fruits to the trapped workers. “Fortunately, there is light inside because the electricity is on. There is a pipeline, and thus water is available. There is a 4-inch pipe, which was used for compression. Through that, we are sending food from day 1,” said an official.

What’s the rescue plan now?

As the rescue mission enters its eighth day to the dismay of relatives of the workers, the administration is mulling newer ways to reach out to them. As per reports, officials plan to conduct vertical and perpendicular drilling of the tunnel if rescuers are unable to drill it horizontally. Larger diameter pipes have also been inserted up to a length of 42 metres through the debris this morning to provide enough food and other essentials to the trapped workers, said a control room set up at the site.

The authorities now have a couple of contingency plans in place. The first contingency plan is exploring whether a hole can be drilled vertically, from the top of the rock that the tunnel is passing through, and get the workers out that way. Vertical drilling is considered one of the potential options to reach the trapped workers and facilitate their rescue.

The other plan, suggested by the railways, is digging a parallel tunnel horizontally, but from the other end of the rock. This tunnel would intersect with the main tunnel at the point where the workers are trapped.

“The new plan is to simultaneously drill vertically as well as horizontally,” said Bhaskar Khulbe, OSD in Uttarakhand government. He revealed that a geological survey was conducted by a team of experts that has helped identify four points on the mountain through which vertical drilling is possible.

“The experts were one in their view that rather than working on just one plan we should work at the same time on five plans to reach the trapped workers as early as possible,” said Khulbe. These plans include drilling from one end to the other on both Silkyara and Barkot sides, vertical drilling from the top of the tunnel and perpendicular drilling.

Efforts to build a platform to start vertical drilling through the top of the tunnel have begun already, he said. “We are trying to make a vertical track from the top of the tunnel. A point at the top of the tunnel has been identified from where drilling will start soon.”

“We plan to drill a 90 metres escape tunnel of 1.2 metres in diameter,” said Jaswant Kapoor, a general manager at SJVN, a government-owned company involved in the rescue efforts.

About the project

The Silkyara tunnel, located about 30 km from the district headquarters of Uttarkashi, is a crucial part of the Char Dham all-weather road project.

As part of Chardham Mahamarg Pariyojana, Ministry of Road Transport and Highways (MoRTH) has taken up construction of a 4.531 km long two-lane bi-directional tunnel at Silkyara to join Gangotri and Yamunotri axis under the Radi pass in Uttarakhand. The construction of this tunnel will immensely benefit the pilgrims as it will provide all-weather connectivity and reduce the 25.6 km snow-affected length of NH-134 (Dharasu-Barkot -Yamunotri road) to 4.531 km resulting in a reduction of travel time to 5 minutes as compared to 50 minutes at present.