Having navigated yet another hurdle, rescuers continued their operation to save 41 workers trapped inside the under-construction Silkyara-Barkot tunnel, inching ever so close to the men who have spent 13 days behind 55 metres of debris.
On Thursday, the drilling machine had run into fore-pole pipes that are generally used in the tunnel roof, following which its blades and platform were damaged. It took the rescuers almost 24 hours to repair the blades, strengthen the platform, and weld a new pipe before the drilling could restart.
The plan remains the same – drill through the debris, insert pipes that are welded together, and pull the men out through those.
It was confirmed by officials that the machine was damaged after reaching around 48 metres inside the debris, and the impact also damaged around 1.2 metres of the 800 mm pipe, which was later cut and removed by rescuers. As a result, on Friday evening, the drilling was set to start from 46.8 metres and is expected to take six-eight hours in case no further blockage is faced.
“By Wednesday, we had inserted around 45 metres of the pipe, but after that, the first hurdle was sensed in the form of some metal girder ribs. We could not push the pipe any further and the drilling was stopped. The machine was pulled back because the auger drilling machine was inside the pipe and needed to be checked manually. After manual checking, the rafters were cut using gas cutters. The machine was then reassembled and the pushing (of the pipes) resumed on Thursday,” said Mahmood Ahmad, Additional Secretary (Government of India) and Managing Director of the NHIDCL.
According to a government-issued bulletin, after the cleaning of the metallic object, the pushing of the pipe started at 1.10 pm on Thursday and could reach up to an additional 1.8 metres. Thereafter, rescuers noted vibration in the machine and its platform being lifted.
“After going 1.8 metres in, we faced another hurdle in the form of fore-pole pipes, and the whole process was repeated. The auger blades were also damaged. After bringing back the machine, we repaired the blades. The workers also cleared the pipes to not leave any metal objects. In the meantime, we also noticed that due to extra pressure and torque, the platform where the machine was installed was weakening. We used the time to strengthen the platform too,” said Ahmad.
The platform for the auger machine was strengthened by way of anchoring, rock bolting, and concreting foundation. Accelerating agents were also used for rapid hardening of the concrete. The work of platform strengthening started around 4 pm on Thursday and continued till Friday afternoon. The auger has also been reassembled and the drilling is expected to resume once the welding of the ninth pipe is complete.
Uttarakhand Government Secretary (Coordination) Dr Neeraj Khairwal said that they also invited a special team of communication technology to use ground penetration radar (GPR) to assess the position of obstruction in front of the pipe. They have found that no continuous metal appears to be there for the next 5.4 metres. This is expected to make pushing the next pipe easier.