Drilling at Silkyara tunnel halts again

Dehradun: Drilling at the collapsed Silkyara tunnel to rescue 41 men trapped inside for 12 days was halted again on Friday. Officials said the auger drilling machine faced a hurdle, apparently a metal object, soon after drilling resumed on Friday, a day after officials had put the operation on hold following a technical snag.

That snag was set right earlier in the day and the 25-tonne auger machine was pressed into drilling through the rubble. However, within an hour after the drilling resumed, it had to be stopped again because of another obstacle. The officials said that this was the second setback in two days.   

According to officials, a ground penetrating radar (GPR) system was employed to detect blockades under the debris across which an escape tunnel is being built.

The GPR had indicated that there were no metal hurdles up to five metres ahead of the passage drilled so far, Neeraj Khairwal, the state's nodal officer for the multi-agency rescue effort, said.

According to officials involved in the operations, the drilling effort to build a rescue passage had, till Thursday afternoon, reached up to 48.6 metres out of the estimated 57 metres of rubble that blocks the tunnel.

However, soon after the drilling resumed on Friday, the auger machine faced a big hollow steel pipe, obstructing the rescue efforts.

"The obstruction had disrupted the auger machine launch platform and narrowed down the circumference of the escape passage created earlier. As a result, nearly 1.5 metres of the 800 mm tunnel had to be removed by us, bringing the net drilling size to 46.5 metres," said Mr Khairwal. 

Further elaborating on the multi-agency efforts since Thursday, Mr Khairwal stated that the NDRF and the SDRF technicians worked hard to cut and clear large steel girdles and iron rods from the path of the auger machine.

A special safety canopy was also developed through pre-cast RCC box culverts and pipes to support the safe evacuation of rescuers working inside the escape passage during emergencies.

Notwithstanding the setbacks, officials involved in the rescue operations assured The Asian Age that drilling for escape passage will resume soon as the removal of obstacles is in the final stage.