Deadline Gets Pushed Back, SLBC Tunnel Needs Three Years Of Work

Hyderabad: The completion of the SLBC tunnel project will take longer than anticipated, pushing back the January 2028 deadline of the government by one more year.

Work of excavating the remaining 9.6 km portion of the tunnel was expected to be resumed this month, but this appears unlikely with the government still sorting out the nitty gritty of setting up an escrow account through which the contractor is to be paid for the work.

Also, the overall distance of the tunnelling still to be completed is expected to go up by at least one kilometre, if not two, including the plugging of the collapsed section in the inlet side where a collapse had occurred on February 22, 2025.

Work will begin from both the inlet side in Nagarkurnool district near the Srisailam reservoir, and in the outlet section in Nalgonda district, using the drill-and-blast method. Workers are expected to excavate around 150 metres from each side, simultaneously, every month.

“With an average of around 300 metres a month, with work going on round the clock, completing the work will take around three years,” a senior official working on the project told Deccan Chronicle.

The government last year had said that it had set itself a January 2028 deadline to complete the work but that is unlikely to be met. Sources said one of the bottlenecks was the delay in setting up an escrow account through which the contractor, JP Associates, was to be paid for the balance of the work.

Before tunnelling is resumed from the inlet side where the collapse occurred, around 150 metres in the destroyed section will need to be ‘plugged’ and sealed, as well as another 120 metres or so requiring the same treatment on the far side of the location.

Last year’s collapse resulted in the death of eight workers. While bodies of two of the deceased were recovered, the remains of six others could not be found as digging through the debris was halted owing to the fragile conditions in the collapsed zone. Once plugged, the remains of those still missing will be buried forever under the Nallamala hills

Once the plugging is done, the tunnel work will move to the left side of the inlet section and follow a curved path, avoiding the shear zone in the rocks and rejoin the original alignment after crossing the danger zone.

Since work will be through the drill-and-blast method, there will be complete control over the intensity of the blasts, the pace of work. The tunnelling will be done in sections, one by one, creating supports by excavating through the top half, and then the bottom half. “The first two months might be a bit slow as things such as evacuation of smoke from the blasts, and removal of muck covering 13 km from the inlet side, and some 20.5 km from the outlet section, will need to be figured out on the go,” the official said.