Silkyara Tunnel Collapse: 31 Metres of Vertical Drilling Done

New Delhi/Dehradun: The vertical drilling from the top of the Silkyara tunnel, where 41 workers have been trapped for the last 15 days, progressed to 31 metres on Monday as a team of rat-hole miners arrived at the site to start manual drilling horizontally through the rubble.

Vertical and manual horizontal drilling are the two methods on which the rescue efforts are being focused at the moment. Work on the other options, such as horizontal drilling from the Barkot end of the tunnel, is also underway as the Prime Minister’s principal secretary P.K. Mishra, Union home secretary Ajay Kumar Bhalla and Uttarakhand chief secretary S.S. Sandhu also took stock of the ongoing rescue operations.

Mr Mishra also spoke to the trapped workers from inside the tunnel and enquired about their condition. He asked them whether they are getting proper food or facing any problem. “Please keep your patience as all are working hard to evacuate you safely. It will happen soon,” he assured the workers inside the tunnel.

Manual drilling was resorted to as the auger drill -- a corkscrew-like device with a rotary blade at the front end --which drilled up to 46.8 metres, got busted as it hit several hurdles on the way and got entangled in a girder in the debris.

A total of 86 metres have to be drilled vertically to prepare an escape passage. Pipes of 1.2 metres in diameter have to be laid vertically through the top of the tunnel on which work began on Sunday as a second option to reach the stranded labourers.

The drilling of vertical escape passage that began on Sunday continued on Monday as well despite water gushing in the borewell.

According to the officials at the ground, despite the growing apprehension about oozing water and boulders coming on the way to the vertical escape passage, the work was going on unhindered.

They also said the rescue team was able to de-water the bore. “We were able to de-water the borewell in time as more than 30 metres of drilling is completed. Although small boulders and other minor obstacles are coming in the way, drilling is moving ahead as per our expectations even as every possible effort is being made to resume the manual excavation of the horizontal passage well,” additional secretary of the ministry of road transport and highways Mahmood Ahmed said. He is heading the rescue operation at Silkyara.

“The broken blades of the auger machine have been fully retrieved. There were some obstacles while retrieving the broken part, but the damage has been fixed”, National Disaster Management Authority member Lt. Gen. Syed Ata Hasnain (Retd) said.

“Now, the manual drilling technique will be employed by today evening with the help of Indian Army engineers, rat miners, and other technicians,” he further added.

A total of 86 metres have to be drilled vertically to prepare an escape passage. Pipes of 1.2 metres in diameter have to be laid vertically through the top of the tunnel on which work began on Sunday as a second option to reach the stranded labourers.

“Around 32 metres of vertical drilling has been done by SVNL. RVNL is working on another pipeline which will become a vertical ‘lifeline’ and it has been inserted up to 75 metres. The estimated depth is around 86 metres,” Gen. Hasnain said.

He further said that the government was fully committed to the safe rescue of all 41 workers who have been trapped in the tunnel since November 12.

When asked about the timeline, the NDMA member said: “It is very difficult to suggest any timeline for the completion of rescue operations. Once the manual digging starts in the evening, we will be able to say something tomorrow morning.”

He noted that manual digging may face some obstacles. “Once we are able to overcome them, progress will be fast,” the NDMA member said, adding that, however, “we cannot give any estimate” for completion of the rescue operation. Gen. Hasnain said that both private and public agencies were involved in the rescue operations.