Even as the agencies engaged in the rescue operation are hopeful that manual excavation of the remaining collapsed portion of the Silkyara tunnel is the best option to reach the trapped workers in the next one to two days, vertical drilling from the top started on Sunday (26 November).
Until late Sunday evening, around 20 out of 86 metres had been drilled.
On 12 November 2023, a collapse occurred in the under-construction tunnel from Silkyara to Barkot due to debris falling in a 60-metre stretch on the Silkyara side.
Immediate mobilisation of resources by the State and Central Governments ensued to rescue the 41 trapped labours.
Officials overseeing the work said it may take three more days to complete the drilling to insert a 1.2-metre diameter steel pipe from top.
Earlier, addressing media persons, NDMA Member Lt Gen (Retd) Syed Ata Hasnain said after drilling through the hill, the crust of the tunnel has to be cut for the rescue of the workers. If it’s successful, then the workers will be lifted by buckets one by one.
Hasnain said the agencies are working on all options while the inserting horizontal line from the Silkyara side and vertical drilling are the two best options.
The NDMA member said that they were hopeful of the cutting and taking out of the entire auger on Sunday night and then manual cutting will start for inserting the steel pipe. Going by the estimated progress of manual cutting, it would take around 18-24 hours to complete that task.
As it had reported earlier, the expert personnel can cut around 1 feet per hour manually.
For faster cutting of the auger agencies are using plasma, magna, laser and gas cutters.
The NDMA member told reporters, “Six plans are being adopted in a synchronised manner. The operation wasn’t put on halt and is still underway.” He also said that workers’ well-being is taken care of amid rescue operation.
Various government agencies are working tirelessly on each assigned specific task to ensure the safe evacuation of the workers. National and International experts are present at the site to advice on the rescue operation. The government maintains constant communication to boost the morale of those trapped.
Freshly cooked food and fresh fruits are being inserted inside the tunnel at regular intervals using the second lifeline (150 mm diameter) service.
Sufficient fruits like orange, apple, banana, etc, along with medicines and salts has also been supplied in this lifeline at regular interval. Additional dry foods are also being supplied for future stock.
A modified communication system with wire connectivity developed by SDRF is being used for communication regularly. People inside have reported that they are safe.
A DRDO Team from Hyderabad with a plasma cutter has arrived at the site. Cutting of auger with plasma cutter started at 4 am on 26 November 2023 which had to be stopped due to operational difficulties at site, and cutting using gas cutters resumed at 7.10 am on 26 November 2023. At the time of reporting, 33.80 metre length of auger has been pulled out.
A platform for launching of drilling machine has been completed.
An access road of 1150 metre has been completed by BRO and handed over to RVNL—machine for drilling towed to location by BRO.
Five agencies—ONGC, SJVNL, RVNL, NHIDCL, and THDCL—have been assigned specific responsibilities, working collaboratively with occasional task adjustments for operational efficiency.