With horizontal drilling to reach the 41 workers trapped in the Silkyara tunnel stuck for the third consecutive day, rescuers began vertical drilling above the tunnel, completing nearly 19.5 meters of boring on November 26. The teams have set a target of vertically drilling through 86 metres of mountain in 100 hours, if there are no unexpected hurdles.
Briefing the media about the vertical drilling, as the rescue operation entered its 15th day, Additional Secretary (Technical, Road and Transport) Mahmood Ahmed 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.
Also read: Uttarkashi tunnel collapse LIVE updates on November 26, 2023
“We should not give targets any more but at the pace with which vertical drilling is going on, I can say we will complete it in 100 hours if no hurdle comes our way,” he added.
One of the rescuers told The Hindu that “the initial few metres will be easier to drill but it will be a challenge when the drilling machine hits the crust [outermost part] of the tunnel”. If this process is completed smoothly, the workers will be taken out in buckets through the vertical hole being bored, he said.
The attention of the authorities shifted to vertical boring when plans to restart the horizontal drilling process yet again failed, with workers struggling to retrieve the broken parts of American Auger machine, which is stuck amid the pipes since Friday night. When the machine is completely extricated, rescuers are likely to commence manual horizontal drilling to reach the workers, who are trapped behind 10-12 metres of debris.
Meanwhile, the Indian Army too has stepped into the rescue operation. In Delhi, National Disaster Management Authority (NDMA) member Lieutenant-General Syed Ata Hasnain informed that a unit of Madras Sappers, part of the Corps of Engineers of the Army, will now help in the operations.
“For manual drilling, the Indian Army along with other rescuers will do rat boring inside the tunnel. They will dig out the debris from inside the tunnel with hands, hammers and chisels and then a pipe will be pushed forward from the platform built inside the pipe,” he added.
In another challenge for the rescue teams, the India Meteorological Department has predicted snowfall and rainfall in Uttarkashi district on Monday, which is located at an altitude of 3,500m above sea level. The weather conditions will further complicate the operation for the rescuers who are already braving difficult conditions including hilly terrain.
The NDMA and SDRF officials say that arrangements have been made to tackle the worsening weather though there are fears that rainfall will hamper the work.
The NDMA member also added that horizontal drilling from another point, the Barkot side of the tunnel, also moved a little on Sunday with rescue teams covering a little over 10 metres after the fifth blast. The perpendicular drilling by the RVNL is yet to start but machines for the same are on the way.
The Tehri and Uttarkashi Police, late on Saturday night had created a green corridor to transport the plasma cutter machine being flown from Hyderabad to the rescue site. The plasma cutter was used, along with gas cutter, to manually dismantle the parts of damaged blades of the Auger machine.
For the uninitiated, on November 12, a portion of the under-construction Silkyara-Barkot tunnel in Uttarakhand collapsed, trapping 41 labourers behind 60 metres of debris. The area of entrapment, measuring 8.5 meters in height and two kilometres in length, is the built-up portion of the tunnel, offering safety to the labours with electricity and water supply available. Food is being provided to the men as rescuers had managed to push a six-inch diameter pipe through the debris inside the tunnel.
Initially, authorities opted to insert a 900-mm pipe through the debris, but safety concerns led to the exploration of multiple rescue options simultaneously.
