Another back-up tunnel in the works in Uttarkashi, trapped men served veg pulao
Rescue operations have entered a critical phase as efforts to save 41 workers trapped in the Silkyara tunnel collapse.
In Uttarakhand’s Uttarkashi continue into the eleventh day. Drilling work resumed late on Tuesday after a pause since November 17, and made significant headway.
Rescue agencies have managed to successfully drill 36 metres through the debris. The drilling gained momentum after breaking through a rock formation that had posed a significant obstacle, causing a days-long delay in rescue ops.
The teams utilized 900 mm pipes to reach a depth of 24 metres, and beyond that, they employed 800 mm pipes to advance further to 36 metres.
The rescuers have created space for a vertical drilling platform by cutting into the mountain above the tunnel. Additionally, plans are underway to construct a micro tunnel perpendicular to the existing tunnel from the left side of the tunnel mouth, although this process is expected to take considerable time.
The trapped labourers received a hot meal last night consisting of veg pulao, matar-paneer, and chapatis with butter, all prepared under medical supervision to ensure easy digestion. The food was delivered through a 6-inch wide pipeline that has also been used to send fruits and establish communication with the trapped workers.
For the first time in days, images of the trapped workers were captured using an endoscopic flexi camera inserted through the pipeline, providing some relief as they showed the men in good condition. Modern drilling machinery from various parts of the country has been brought to the site to support all types of drilling operations necessary for the rescue.
Uttarakhand Chief Minister Pushkar Singh Dhami has stated that the priority remains the safe evacuation of all workers, and that Prime Minister Narendra Modi is being updated regularly on the progress of the rescue efforts. The National Disaster Management Authority (NDMA) has confirmed that there is sufficient water, oxygen, power, and light inside the tunnel where the workers are trapped.
Highways authority orders audit of tunnel projects
In the aftermath of the Uttarkashi mishap, the National Highways Authority of India (NHAI) will conduct a comprehensive safety audit for key ongoing tunnel projects, sources told India Today.
NHAI’s regional offices have been directed to engage experts in the field for the upcoming safety audits. More than two dozen significant tunnel projects are slated for urgent evaluation as part of this initiative.
To ensure a thorough examination, NHAI plans to enlist agencies with substantial experience in tunneling work. This includes government entities and other foreign experts known for their proficiency in such projects.
The primary focus of these safety audits will be to assess and enhance safety measures across all ongoing tunnel projects, according to sources.
Focus back on horizontal drilling
Horizontal drilling through the debris was put on hold last Friday afternoon after the heavy duty auger machine encountered a hard boulder, making rescue agencies consider other approaches as well.
But on Tuesday, remarks by National Disaster Management Authority member Lt General (retd) Syed Ata Hasnain, Road Transport and Highways secretary Anurag Jain and Uttarakhand CM Dhami made it clear that resuming this paused operation was the main priority.
International tunnelling expert Arnold Dix, who is at the site, said vertical drilling demanded precision. While drilling from the top, even a small mistake could mean missing the tunnel, he said. The horizontal drilling option involves inserting sections of a steel pipe as the machine drills through. The workers can then crawl out of the pipeline.
The “second-best” option involves drilling more than 80 metres vertically from above the tunnel to reach the two-kilometre built-up stretch where the workers are now confined. Drilling from the tunnel’s Balkot end is another alternative on which the rescue agencies are working. Drilling parallel tunnels is also being considered. Some of the heavy machinery for these new approaches has reached the disaster site.