Why Silkyara tunnel crisis is more serious than you think it is

It is now Day 14 and the 41 workers trapped inside the jaws of the Silkyara–Barkot tunnel in Uttarkashi are still waiting to be rescued.

A slew of government agencies—PMO, IAF, NHIDCL, ONGC, DRDO, BRO, Rail Vikas Nigam, National Disaster Response Force, State Disaster Response Force, Satluj Jal Vidyut Nigam Limited (SJVNL), Tehri Hydro Development Corporation (THDC), ISRO, Geological Survey of India—and several private agencies including the Trenchless Engineering Private Ltd and L&T Safety Unit have been roped in to help with the rescue operations.

Overseeing them is the National Highways & Infrastructure Development Corporation Ltd (NHIDCL), the key agency entrusted with the construction of the Char Dham project.

In June 2018, NHIDCL signed a contract for Rs 853.79 crore with Hyderabad-based Navayuga Engineering Company Ltd (NECL) for engineering, procurement and construction of the Silkyara–Barkot tunnel.

NHIDCL director Anshu Manish Khalko spoke of a ‘five-pronged approach’, with the American Augur machine which had broken down on November 16 having been repaired and pressed into action once again. The Augur machine will restart horizontal drilling from the Silkyara side with 800 mm pipes having been drilled into the 900 mm steel pipes in order to provide additional support.

The collapsed section is 270 metres from the mouth of the tunnel from the Silkyara side. On 17 November, the earlier operation had been abandoned because the machine had encountered hard boulders and been damaged in the process.

THDC has been asked to initiate drilling operations from the Barkot end. So far, using the drill and blast method, they have succeeded in excavating a 6.5-metre-long drift.

A third plan being executed by SJVNL is to go in for vertical drilling from the hillock above the tunnel. A drilling machine for this operation arrived at the site on the evening of 21 November. Experts from ONGC have been requisitioned to help in this process. Additional machines have been sent from Gujarat and Odisha. Micro-drilling through the tunnel’s left side has also been operationalised.

Despite the veritable alphabet soup of agencies involved, the workers are still stewing underground. No one is willing to give any clear timeline. The minister of road transport and highways Nitin Gadkari, after making an on-the-spot assessment, had said it would take two to three days, a timeframe echoed by Gen V.K. Singh (retd), Union minister of state for road transport and highways.

While the prime minister’s former advisor Bhaskar Khulbe told the press, in the course of an informal interaction, that it would take around “five to six to seven days”, the Uttarakhand secretary for road transport said the operations could take 15 days or more. Meanwhile, Australian tunnelling expert Arnold Dix, who has been flown into Uttarkashi for additional support, is reported to have told local journalists that rescue operations could go on till Christmas.

Some Indian safety experts point out that Dix’s area of expertise is fire safety and air quality in tunnels, and wonder if he will be able to tackle the complex problem of the current tunnel collapse. Gadkari, Singh and Dix had all remarked on these hills being comprised of “loose stone and mud”—deadly for tunnels and tunnellers—with a large limestone component.

If this detail is being highlighted now, in the wake of this disaster, why was the fragile composition of the Himalayas not emphasised when the network of tunnels was at the drawing board stage?

Uppermost on the minds of the workers assembled outside the Silkyara tunnel, their family members as well as the public at large is why Navayuga Engineering Company (NEC) had failed to provide an escape route which is mandatory in all tunnel constructions.

Dehradun-based Congress spokesperson Sujata Paul pointed out, “Not only were safety ducts and an escape route missing in such a long tunnel, but NEC and NHIDCL had also failed to prepare any safety plan in case of such an emergency. At the time of the mishap, there was only one JCB at the site of the accident. Two of the Augur machines broke down and a third had to be sent for from Indore”.

No FIR has been lodged against NEC for criminal negligence. When the VIPs present at the accident site were asked why, they sidestepped the question, insisting their present focus was to ensure that the workers emerged safe and sound.

Reena Paul, a Dehradun-based environmentalist rued that “the tunnels of Uttarakhand have become death traps. A few days ago, a landslide at the Daat Kali tunnel connecting Saharanpur to Dehradun was blocked for three hours due to a landslide, with commuters trapped inside the tunnel complaining of suffocation and breathlessness.”

Why did the Silkyara tunnel not have an escape route? When the government sanctioned the tunnel project in February 2018, it clearly stated that it would include an “escape passage”.

The Dehradun-based NGO Samadhan has filed a PIL in the Nainital High Court demanding a criminal case of negligence be filed against the concerned authorities for major safety lapses in the construction of the Silkyara tunnel. The court has issued notices to the state government demanding it submit its reply within the next 48 hours.

Dr P.C. Nawani, former director of the Geological Survey of India, insists that escape routes are crucial to such large projects. Not only do they help save lives and facilitate rescue work, they facilitate the workaday supply and delivery of materials inside the tunnel.

Nawani also stressed that tunnel construction needs inputs from an expert team of engineering geologists, but this work tends to be handed over to contractors who are prepared to use all kinds of shortcuts with little knowledge of the existing terrain.

Tunnels are an integral part of road, rail and hydropower projects across the world. So too, in India. But given that the Himalayas are an ecologically sensitive region, due care is imperative. What kind of safety can these rail tunnels assure, given that the mountains in the Himalayas comprise of soft rock? The 17 tunnels coming up as part of the Rs 16,000-crore Rishikesh–Karnaprayag project include a 15.1 km tunnel, expected to be longest in India. A safety audit of this rail link becomes imperative in the light of the Silkyara accident.

In 2020, NEC, along with other private companies, was given a contract to construct some of these rail tunnels. But NEC’s safety track record in the past is also questionable. This was manifest recently when a special-purpose mobile gantry crane used in bridge construction collapsed on the Samruddhi Expressway killing 15 workers, with an engineer and five other workers trapped under the debris. This accident occurred on 1 August 2023 in the Shahpur tehsil of Thane district.

The first phase of the Samruddhi Expressway was inaugurated by PM Modi in December 2022. The accident occurred during the third phase. An FIR was registered against the sub-contractors that had been hired by NEC. (The Hyderabad-based company is seen to be close to Chandrababu Naidu. When power changed hands in Andhra Pradesh in 2019, the new chief minister Jagan Mohan Reddy cancelled several other contracts that had been given to NEC in the state.)

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The Uttarakhand state government led by chief minister Pushkar Singh Dhami has issued a statement that a reassessment of all the tunnels under the Char Dham project will take place in the next six months. Unless experts are roped in, such a reassessment will serve little purpose. One wonders, will they review the validity of hare-brained schemes such as building the world’s largest road tunnel connecting Dehradun to Tehri?

The environment impact of these rail tunnels also needs fresh evaluation. Dr C.P. Rajendran, renowned geologist and an expert on earthquakes, points out, “There is a belief that building tunnels may decrease infrastructural impact on the environment. In fact, these subsurface structures could result in gross damage to the environment, including the concentration of pollutants from traffic exhaust compounded by a micro-environment with no sunlight and limited dispersion in long-distance tunnels.”

Rajendran goes on to add, “Rail traffic may rely on electric locomotion, but constant vibrations during train movements is another danger when it comes to tunnels—keeping the mountain slopes eternally unstable and thus making them vulnerable to slides at the slightest trigger. Blasting for tunnels weakens the rock formations, which further leads to landslides, besides generating huge quantities of excavated rock waste. The irreversible impact on groundwater, such as descending water levels, has also been observed in tunnel construction areas.”

Excessive tunnel building is one of the most alarming aspects of the rampant construction activity going on in the Himalayas. A graph prepared by scientists revealed that landslides have increased by 2,900 per cent in Uttarakhand in the last five years.

Landslides do not occur in isolation. Depending on the nature of the rock, their competency and the blasting methods employed, road and dam constructions act as trigger mechanisms. The geology of the rocks and the nature of fissility within them (their tendency to split along planes of weakness) are important criteria to be considered. Many times, a slip occurs along such fractures.

The instability of the hills has been all too evident in the Silkyara tunnel crisis. As experts drilled into the rubble, vibrations triggered landslides that only served to delay the rescue operation.

The only saving grace in this sad saga is that the authorities have managed to drill a six-inch pipeline through which the trapped workers have been sent hot khichdi (in bottles), fruit, anti-depressants and electrolytes. An endoscopic camera was also pushed through, so that photographs of the trapped workers could be beamed to their families in Jharkhand, Bengal, Odisha, Bihar, Uttarakhand and Himachal Pradesh.

Another relief is that electricity has not been switched off in the tunnel and the workers have around 1.5 kilometres of space to move around in. Small mercies that feel like big bonuses to those still waiting to be saved.