Manas Dasgupta
NEW DELHI, Nov 27: Even as the vertical drilling from the top of the hill is making swift progress and the horizontal drilling to begin soon manually after the debris of the broken auger machine cleaned out, all concerned in the operation to rescue the 41 workers trapped in collapsed tunnel in Uttarakhand are keeping their fingers crossed fearing the unexpected.
The operation of the last two weeks since the workers got trapped on November 12 has been a story of new challenges at every corner and rescue teams tweaking their plans to meet them. The past 16 days have seen government authorities constantly fine-tune their strategies and find new approaches to bring out the men at the earliest.
At present rescue teams are drilling from multiple directions to reach the workers. The vertical drilling from the top of the hill has made swift progress as 31 metres of drilling work has been completed so far out of the 86 metres needed to reach the trapped workers in the Silkyara tunnel, as per officials. Now the drilling work is being done to lay an 800/900 mm or 1.2 m diameter pipeline to aid the rescue. The teams have set a target of vertically drilling through 86 metres of mountain in 100 hours, if there are no unexpected hurdles.
The rescuers may face difficult weather conditions over next two days as weather bureau has predicted rain and snowfall at the tunnel rescue site. The temperature at the site has also dropped to as low as 4 degrees Celsius. While this could create complications in the rescue operation, the teams working on the ground said they are prepared to deal with the challenge. The Highways and Infrastructure Development Corporation Limited (NHIDCL) Managing Director Mahmood Ahmad said the rescue workers were “trained in working in every situation, so that’s not a worry for us.”
Briefing the media about the vertical drilling, Mr Ahmad said there could be a need to change the “needle” or head of the drilling machine after a point of time and necessary arrangements for the same are already in place. National on Monday informed that the work of the vertical drilling at Uttarkashi tunnel where 41 workers remained trapped will be completed by November 30.
“We have completed around 30 meters of drilling. The current machine that has been deployed can drill around 40-45 meters. We have brought two more machines for this purpose. SJVNL has brought those machines. Changeover machines will take time. We are expecting vertical drilling work would be completed by November 30.”
Manual drilling at the Uttarkashi site is set to begin by Monday evening after an auger drill machine manufactured in the US got stuck in the debris. The drill — a corkscrew like-device with a rotary blade at the front-end — had drilled through more than 46 metres of debris. As the machine drilled through, pipes were pushed in to create an escape passage. A couple of days back, it appeared that the operation would be completed soon, but snags in the drill dashed hopes.
About 14-odd metres of drilling was left when the machine’s blade got stuck in the debris and the drill broke down. International tunnel expert Arnold Dix, who is at the site, said the auger machine was “busted”. “Augering is finished… the auger is broken, destructed,” he told the media. Thereafter, a specialised gas cutter was flown in from Hyderabad to cut and remove the parts of the auger drill stuck in the debris so that manual drilling could begin. The plasma cutter completed its task on Monday morning.
With the 25-tonne auger machine breaking down, rescue teams decided to pursue multiple strategies simultaneously. Manual drilling is aimed at completing the task the auger drill started. A team of 11 has been flown in from Delhi for this task. These include six specialists and five more in reserve. Rescue teams said they will go inside the 800 mm pipe to remove the debris manually. This method involves two-three drillers entering the pipe and using hand-held tools to clear the debris blocking the pipe’s way. The waste generated during the digging is sent out through wheeled vessels. One of the specialists said “A shovel and other specialist tools will be used. For oxygen, we will take along a blower with us.”
Manual drilling is a tiring task and the diggers take turns. These professionals are also called rat miners for their rat-like skill in boring. According to rescue teams, these professionals are skilled in cutting through metal barriers too. Manual drilling method is set to begin today. Rescue teams at the site said this morning that the gas cutters used to remove parts of the auger drill from the debris had generated heat inside the pipe and they were waiting for it to cool down before manual drilling starts.
When asked whether going through 800 mm diametre pipes would not be difficult for them, one of the team members said they had experience of manually clearing debris through even 600 mm diametre pipes. The rat miners will go inside the pipes wearing a helmet, a uniform, a mask and glasses. Though a time-consuming process, manual drilling seems a feasible option as only around 10-12 metres through the rubble remain to be drilled to complete the escape passage.
With the horizontal drilling operation facing repeated hurdles, rescue teams have put in action a vertical drilling plan. This plan involves drilling horizontally from a point about 300 metres from the mouth of the tunnel and then drilling vertically down about 86 metres. Former chief of Border Roads Organisation Harpal Singh, who is at the site, has said 31 metres of drilling has been completed. A big challenge in the vertical drilling method is how to drill through the crust or the roof of the tunnel. Rescue teams plan to drill horizontally for a short distance once they reach the crust, and then drill through it to ensure that the workers trapped beneath it are not injured.
The vertical drilling method was put into action since Sunday by Satluj Jal Vidyut Nigam, a public sector undertaking involved in hydroelectric power generation. This method has progressed smoothly so far. The team drilling through the mountain plans to pull up the 41 labourers using a harness machine once it reaches them. According to National Highways and Infrastructure Development Corporation Limited, the drilling work is expected to be completed by November 30.
Rescue teams have also started an operation to reach the trapped workers through the other end of the tunnel from Barkot. But that is a method that is going to take a long time. The rescuers have to drill through nearly 480 metres. Four blasts were carried out yesterday to help them progress. Only 10 metres have been covered so far.
There is another plan that involves building a mini tunnel along the left side of the tunnel. This mini tunnel will be perpendicular to the Silkyara tunnel, and the plan is to rescue the trapped workers through it. According to sources, this perpendicular mini tunnel will be 180 metres long, and it will take another 10 to 15 days to be built. Work on this is expected to begin on Tuesday.
As the rescue operation drags on, there is concern over the mental and physical condition of the workers. While they are now receiving food and other essential supplies through a pipe pushed through the debris, their mental state remains a cause for worry. Over the past 16 days, they have gone through the trauma of being stuck inside a tunnel, the fear that help may not reach them, some moments of hope when it appeared that they will soon be out and a return to uncertainty on when they will see light at the end of the tunnel.
Rescue teams are aware that the mental state of the workers will play a crucial role in keeping them fine till the end of this long-drawn operation. They have now roped Bharat Sanchar Nigam Limited to provide the trapped workers with a landline connection so that they can talk to their families.
BSNL official Kundan said they are in the process of sending a small landline phone to the trapped workers through the pipe. “Through this, they will be able to talk directly to their families,” he said. The BSNL, he said, has set up a small telephone exchange at the tunnel site for this purpose.
Some mobile phones have also been sent through the pipe so that the trapped workers can play video games to distract themselves from the harrowing wait to be rescued. Rescue teams said there are plans to provide Wi-Fi connectivity because there is no cellphone network inside the tunnel. Board games have also been sent through the pipe.