Uttarkashi tunnel collapse: Mock drills to be conducted to avoid similar incidents, says NDMA

The workers were trapped inside a 2-km stretch of under-construction tunnel.

Once the rescue operation to save 41 workers trapped inside the under-construction Silkyara tunnel on the Char Dham route is completed, the government will come out with new standard operating protocols for tunnel collapse cases and will also carry out mock drills across the country, the National Disaster Management Authority (NDMA) said on November 28.

"After the Balasore train accident, the NDMA worked with the Indian Railways and carried out mock drills across the country on how to avoid such accidents in the future, once the workers are rescued from the Silkyara tunnel similar such mock drills will be carried out," NDMA Member Lt Gen (retd) Syed Ata Hasnain told reporters.

He added that the Indian government has learned a lot from all the unfortunate accidents and disasters that have taken place in the country this year, and going forward will be better prepared to avoid such incidents.

National Highway Authority of India (NHAI) Member Vishal Chauhan also said that once rescue operations are completed the government will carry out an audit of all ongoing tunnel projects.

"We will take lessons from this too and see how we can improve our SOPs [standard operating procedures] and how we can improve our designs to make these projects safer. Once the operation is completed, these things will happen then," Chauhan said.

He added that the Delhi Metro Rail Corporation (DMRC) and Konkan Rail Corporation (KRC) have been assigned the task of the review, which he said have extensive expertise in tunnelling.

As of 1600 IST on November 28, rescue teams to save the 41 workers were just 2 metres away from workers, who had been trapped in the Silkyara tunnel for 16 days.

Rescue operations are near a breakthrough and as many as 12 rat-hole mining experts were called in to finish the last stretch of drilling by using hand-held tools in a confined space after the broken parts of the auger drilling machine were removed from the rubbles.

Rat-hole mining experts were called after the blades of the augering machine drilling through the rubble of the collapsed Silkyara tunnel were on November 25 stuck in the debris.

Giving an update on the rescue operations, Hasnain told reporters that 58 metres of drilling has been done, and the rescue pipe has to be pushed towards the trapped workers by another two metres.

Once the breakthrough is achieved, it would take 3-4 hours to bring out all the trapped workers, Hasnain said.

"It will take 4-5 mins to pull out each worker on a wheeled stretcher through the pipe and therefore in total it will take around 3-4 hours to complete the evacuation process," he added.

"Vertical drilling is also still ongoing at the Silkyara tunnel, in case the horizontal drilling faces further obstacles," Hasnain added.

At the time of reporting 45 mtrs of vertical drilling had been completed, Hasnain added.

On November 12, a part of the under-construction Silkyara-Barkot tunnel in Uttarkashi caved in and trapped 41 workers. The tunnel is part of the Char Dham Project, which has been flagged over environmental concerns over the years, owing to the fragility of the Himalayan geology.

The workers were trapped inside a 2-km stretch of under-construction tunnel. They had access to water and the area was well-lit as electricity connections were not snapped when the incident happened. Through pipes, they were also provided with food and oxygen was also being pumped.

The Silkyara-Barkot tunnel, part of the Char Dham project, was being built by a contractor under the aegis of a public sector undertaking (PSU) of the Ministry of Road Transport and Highways (MoRTH).

The NHAI has been engaged in the rescue operation. For a long time, projects under the Char Dham initiative have raised concerns as they are located in the fragile Himalayan region.