In a crucial development on day 14 of the ongoing rescue mission at the collapsed Silkyara tunnel in Uttarakhand, experts grapple with challenges as the auger machine encounters debris, potentially prolonging the rescue of 41 trapped workers by several days or even weeks.

As the auger blades became stuck in the rubble, rescue officials shifted their focus to two alternatives. The first involves manual drilling through the remaining 10- or 12-metre stretch of debris, while the second, more likely option, is drilling down 86 meters from above.

Assistant Professor Vivek Padmanabha from Civil Engineering at IIT Guwahati explained the challenges, citing geo stress and potential issues such as lack of geological knowledge, improper design, faulty construction, and inadequate excavation plans. He emphasized vertical drilling as a process to create earth shafts, providing direct access for ventilation and communication. The professor highlighted the importance of understanding varying geo stress levels at different depths.

Vertical drilling is a process in which we drill boreholes down the earth's surface creating earth shafts. This is for providing direct access to ventilation and communication. If the borehole is wide enough then we can evacuate the trapped persons. The most important thing is geo stress are different at different levels, so vertical stress will have maximum pressure," explained Professor Padmanabha, noting that casing would prevent rocks from falling into the bore well.

Arnold Dix, an international tunnelling expert present at the site, reiterated his commitment to getting the workers out "by Christmas," a month away, as the rescue team considers alternative approaches in their relentless efforts to save lives. The mission began on November 12 following a tunnel collapse caused by a landslide on Uttarakhand's Char Dham route.