Uttarakhand tunnel rescue updates: Swift progress in vertical drilling as trapped workers await freedom

The 41 workers remain trapped inside a tunnel in northern India's Uttarkashi, about 400 km north of New Delhi since November 12. After struggle to achieve success in horizontal drilling amid series of setbacks, Sunday (Nov 26) was the first day of vertical drilling.

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Hailing from Uttar Pradesh's Lakhimpur Kheri, a person identified with his last name Chaudhary has his son stuck inside the tunnel along with 40 others.

"Once he comes out, we will never allow him to work here again," he was quoted as saying by the Press Trust of India.  

Chaudhary spoke to his son Manjeet on Sunday through a communication channel which has now been set up by the authorities.

"We are very poor and came here after taking a loan of ₹9,000 against my wife's jewellery. Here, the administration gave me a jacket and shoes. They also repaid my loan."

An official at the site of crisis, while referring to the rescue path being drilled, said that the vertical drilling for path is 1.2m in diameter.

A total of 86 meters is to be drilled of which 19.2 meters has been completed. The current machine will drill for 40-45 meters and then another machine will be brought in to complete the whole 86 meters. 

"We have estimated 4 days to complete the drilling. So far there is no obstruction," the official said. 

Of the three drilling efforts at Uttarakhand's Silkyara tunnel, one is complete. The six inch diameter drilled horizontally is already acting as a lifeline for food and essential items. 

Another 8 inches (diameter) drilling is nearing completing that will additionally be used to send in optical fiber for communication. Length-wise, 78 meters of this drilling has been completed and it needs to drill 8 meters more.

Diametrically, a 1.2 metre drilling is ongoing vertically which will be used to take out those stranded.
 

Rescuing efforts through vertical drilling is almost at its completion, reports said. Meanwhile, sources indicate that almost 78 metres of drilling have been completed.

Around 86 meters has to be drilled to begin the rescue works.
 

A plasma cutter and laser cutter were brought to Silkyara to cut the auger machine. Reports said that late at night, the Dehradun, Tehri, and Uttarkashi police administrations made a green corridor and sent the plasma cutter and laser cutter to the Silkyara tunnel.

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Union Minister General VK Singh (Retd) reaches the site where vertical drilling work is in progress.

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"The best plan so far is plan 1 (horizontal drilling)...where the drilling inside will be done manually...The second best alternate technique remains vertical drilling..." Member of the NDMA, Lt General Syed Ata Hasnain (Retd.) said. 

Silkyara tunnel rescue operation: Member of the NDMA, Lt General Syed Ata Hasnain (Retd.) said, "Our plan 3 (Perpendicular, covering 170 metres) has still not been adopted...The machine for sideways drilling is expected to reach the Silkayra tunnel rescue site during the night..."
 

"...Vertical drilling started at around 12 noon today and 86 meters of vertical digging required to reach trapped workers...15 metres of drilling has already taken place..." NDMA Member Lt General Syed Ata Hasnain (Retd.) said. 

Silkyara tunnel rescue operation: Member of the NDMA, Lt General Syed Ata Hasnain (Retd.) said that the auger that broke while drilling is now being pulled out and a distance of 13 metres still remains to be covered for it to be completely out. 

"...Yesterday the auger machine was stuck, the blades broke done so manual cutting had to be done and for that, the equipment had to come from outside...Through Airforce and IndiGo's charter flight...all three equipments have reached there...Earlier, we were getting a speed of 4-5 m/hr but now that might not be the case but it is a fail-safe technique..."

He said that a plasma cutter from DRDO was also roped in for the ops. The official said that the broken auger should be out tonight. 
 

Silkyara tunnel rescue operation: NDMA Member Lt General Syed Ata Hasnain (Retd.) said, "...All of them (workers) have been getting their sustenance, food, medicine...Medical and psycho-social experts are there and doing their work...All precautions are being taken for the safety of all...Six plans are working...These plans are being adopted in a very synchronised way..."

In response to a query on an 'escape passage' alongside tunnel construction, NHIDCL Managing Director Mahmood Ahmad said, "We too thought about this issue. A committee has been formed over this and the findings will be out. As on today, our first goal is to safely bring out our 41 workers."

Uttarakhand tunnel rescue: Mahmood Ahmad, the Managing Director of National Highways & Infrastructure Development Corporation Limited (NHIDCL) said that there is a target of 15 days for the horizontal drilling to be successfully done. 

"Work on concrete bedding has begun. We expect that two days from now, we have fixed 28th November as the date when drilling begins. This is a long process. We have a target of 15 days for the horizontal drilling to be successfully done...We also want to make a drift tunnel, design has been made and approved...We are working on these various sides...Work from Barkot's side is facing difficulties..." he said. 
 

The Managing Director of NHIDCL Mahmood Ahmad said that since Saturday (Nov 25) the team has explored various alternative plans for the rescue ops. "We have now come to a stage where we started working on 2-3 more options since yesterday," he said. 

NHIDCL Managing Director Mahmood Ahmad during a presser said that spots for vertical drilling are identified with the help of experts and geologists and 15 metres of drilling ops are already finished. 

We identified spots where the drilling could be better...drilling of almost 15 metres is complete. We identified a spot where we estimate that a total drilling of 86 metres has to be done. 15 metres is done and we think that this will complete in the next 2 days."

He noted, "We have told SJVNL (Satluj Jal Vidyut Nigam) to do vertical drilling of 1 to 1.2 metre diameter for us." 

Uttarakhand tunnel rescue: Managing Director of National Highways & Infrastructure Development Corporation Limited (NHIDCL) Mahmood Ahmad while giving the latest updates on rescue ops anticipated that vertical drilling operations will take next two days to complete. 

The work of placing the machine for vertical boring on top of the tunnel was started from yesterday evening.

JVN began work on second best alternative approach of vertical drilling  on Sunday involving drilling from the hill at the top of the tunnel. 

Uttarakhand Chief Minister Pushkar Singh Dhami said, "The plasma machine that has been brought from Hyderabad has started working since this morning. The cutting is going on rapidly. 14 metres more remain (to be cut)." 

He added, "The auger machine has to be cut and brought out. It seems that it will be completed soon, within a few more hours. After that, manual drilling will begin." 

A senior official said, "We are also considering providing a cricket bat and ball to the workers so that they can play cricket. You can spend your time playing because there is a lot of space inside the tunnel where the workers are trapped, so cricket can be played easily."

Uttarakhand CM Pushkar Singh Dhami says, "The plasma machine that has been brought from Hyderabad has started working since morning. Cutting is going on rapidly. 14 metres more remain (to be cut). The auger machine has to be cut and brought out. It seems that it will be completed soon, within a few more hours. After that manual drilling will begin."

Officials at the site have confirmed that vertical drilling will resume today; however, they said it will take more time to conclude the rescue operations now. Also, the Indian Army is expected to carry out manual drilling.

Replacing the broken American auger, new machine has arrived at the tunnel site. Now, downward drilling will be started using this machine by Sunday afternoon.

Earlier, Indian Air Force flew in critical equipment required in the rescue operations, delivering the essential tools to Dehradun. The equipment will soon reach Silkyara, Uttarkashi.

Indian Army's Madras Sappers will carry out manual drilling at the tunnel site. Earlier, officials at the site released this statement:

"The plasma cutter has arrived and has begun cutting the American Auger. Along with plasma cutter, top laser cutter is also being used. If the American machine is taken out by these cutters by evening, then the tunnel work can be completed in 12-14 hours."

"The possibilities of vertical drilling are negligible as at this time all 41 people inside the tunnel are comfortable, and are getting food. There are chances that there will be pressure on the tunnel and their pipes will break due to debris if vertical drilling is done."

"It is possible that this is why the equipment for vertical drilling has been moved up, but this will not happen. To do manual drilling, Indian Army along with civilians will do rat boring inside the tunnel. After digging by hand and with tools like hammer and chisel, the soil will be taken out and then the pipe will be pushed forward from the platform."

No rescue timeline has been given by the officials. However, as the augering machine broke down on Saturday, it is expected to take a few more days, even weeks, to conclude. On Saturday, International tunnelling expert Arnold Dix stressed on his promise of getting the trapped workers out “by Christmas." 

After auger machine broke down, experts are exploring two alternatives to further the rescue operation: Manual drilling through the remaining 10 or 12-metre stretch of the rubble or, more likely, drilling down 86 metres from above.

"When soil and rocks are subjected to a tremendous amount of pressure, also called geo stress when we try to make a tunnel and this disturbs the equilibrium. Some rocks adapt well and some do not. Rocks at Uttarkashi tunnel have not been adapted well," Assistant Professor Vivek Padmanabha, Civil Engineering IIT Guwahati said.

"There could possibly be three issues like lack of knowledge of geology, improper design and faulty construction. The third one is the lack of excavation and remediation plans," he said.

"Vertical drilling is a process in which we drill boreholes down the earth's surface creating earth shafts. This is for providing direct access to ventilation and communication. If the borehole is wide enough then we can evacuate the trapped persons. The most important thing is geo stress are different at different level so vertical stress will have maximum pressure," the professor said.

"The casing will prevent rocks from falling in the bore well," he added.

(With inputs from agencies)

Uttarakhand Chief Minister Pushkar Singh Dhami said Saturday that the auger machine was still stuck inside the debris and equipment were being flown in from Hyderabad to get it out.