First video of manual drilling inside collapsed Uttarkashi tunnel to rescue 41 workers released
Concurrently, vertical drilling from above the tunnel has reached a depth of 36 meters, out of the required 86 meters. Twelve rat-hole mining professionals are manually digging and excavating horizontally through the remaining 10- or 12-metre stretch of rubble from the fallen segment of Uttarakhand's Char Dham path.
This drilling was previously done by a massive auger machine, which became trapped in the rubble on Friday, leading officials to focus on an alternate option: drilling down from above the tunnel. Approximately 40% of the 86-metre vertical drilling required has now been completed.
Officials determined that the last stretch of the horizontal through-the-rubble alternative would be handled manually, with individual workers going into the escape path with drills and gas cutters to attack obstructions like iron girders. By monday evening, the last piece of the jammed auger had been taken out and a steel pipe had been placed farther into the partially completed escape path.
Lt Gen (retd) Syed Ata Hasnain of the National Disaster Management Authority (NDMA) announced in delhi that vertical drilling began on sunday and has already reached a depth of 36 meters.
When the one-metre-wide hole breaches through the top of the tunnel below, rescuers aim to bring workers out by Thursday. Another eight-inch-wide shaft dug from a neighboring site has reached a depth of around 75 meters. This probe, which is also expected to act as a supply line for the trapped workers, has indicated that there were no serious geological obstacles for the main shaft up to this point, the NDMA member and officials at Silkyara said.