Explained: The five-option plan to rescue workers trapped in Uttarkashi's Silkyara tunnel

Eight days after over 40 workers found themselves trapped inside the under-construction Silkyara tunnel at Uttarkashi in Uttarakhand, the drilling work, which has been on hold, will restart on Monday. This comes as the rescue workers embark on the next stage, a five-option plan devised by the government. 

Officials decided to implement the multi-pronged approach after the initial plan to dig through the debris to insert a steel pipe, which will serve as an escape route, failed. The American-made heavy-duty auger machine encountered a hard obstacle after about 22 metres. 

All the workers are safe, authorities said. There is light inside because the electricity is on and a pipeline to supply water.

Explained: Five-pronged approach

On Sunday, a road was laid to the top of the hill for digging a vertical shaft down into the tunnel. 

Transport and Highways Secretary Anurag Jain has said that the government has devised a five-option action plan to rescue the workers at the earliest.

As per the plan, five options were decided and five different agencies were detailed to carry out these options. "They include Oil and Natural Gas Corporation (ONGC), Sutluj Jal Vidyut Nigam (SJVNL), Rail Vikas Nigam Limited(RVNL), National Highways and Infrastructure Development Corporation Limited (NHIDCL), and Tehri Hydro Development Corporation Limited (THDCL)," he said.

The ONGC will use its expertise in deep drilling to dig a vertical drill from the Barkot end. It has already started the initial work. The SJVNL will also carry out vertical drilling to rescue the trapped labourers. It has brought equipment from Gujarat and Odisha through Railways, as a 75-tonne equipment it could not be airlifted. 

Jain said RVNL has started working on another vertical pipeline for the supply of essential items after the Border Roads Organization completed building an approach road in just one day. The THDCL will carry out the micro tunnelling Sunday night from the Barkot end of the under-construction tunnel on the Char Dham route. The work began on Sunday night itself.

NHIDCL MD Mahmood Ahmed has been made the charge of coordination with all the central agencies and has been stationed in Silkyara.

Jain said that the government is keeping constant communication and making all efforts to keep up the morale of the labourers trapped inside the tunnel. "The area in which the workers are trapped is 8.5-metres high and 2-km long. This is the built-up portion of the tunnel where concreting work has been done providing safety to the labourers," he explained. 

NHIDCL is creating another six-inch pipeline for food, and drilling of 39 metres out of 60 metres is completed. "Once this tunnel is ready, it will facilitate delivery of more food items," Jain added.

Meanwhile, Union Minister Nitin Gadkari, who visited the site on Sunday, told reporters at Silkyara said preparations were underway to restart the auger machine and resume drilling and pipe-laying at the tunnel.

Gadkari said the auger machine had worked well through the soft soil but there were vibrations in the tunnel when it encountered a hard object. "This posed a danger to the safety of the rescue workers. Though I am no technical expert, in the given circumstances horizontal digging seems the best option. If the auger machine does not encounter any obstacles it might reach the trapped workers in two and a half days," he said.

There is also a plan to use robots to see if another pipe for life support could be pushed through the space between the top of the debris and the tunnel roof.

(With PTI inputs)