Telangana: Uncertainty clouds completion of Srisailam Left Bank Canal tunnel project

Alternative plans are in consideration for the completion of the Srisailam Left Bank Canal tunnel project

Hyderabad: Alternative plans are in consideration for the completion of the Srisailam Left Bank Canal (SLBC) tunnel project, which was mired in uncertainties after the February 22 roof collapse.

The Tunnel Boring Machine (TBM), with its cutter component still intact, has been reduced to wreckage following the collapse. Acquiring a new TBM to resume operations would involve time and financial costs.

It would add up to the overall cost of the project. Experts have reportedly made it clear that continuing the project using the damaged TBM is no longer feasible.

Efforts to remove the damaged TBM are in progress but remain complex. With the tunnel works initiated way back in 2005, the project suffered multiple setbacks.

Its completion is now a major concern before the government. Work on only 6.01 kilometres of critical stretch in the inlet tunnel has been left unfinished.

The inlet tunnel connects the project to the Srisailam reservoir, a critical point for drawing water.

Finalisation of alternative plans for completing the project would involve studies by agencies like NGRI and the National Remote Sensing Centre (NRSC) to study ground conditions.

Based on their findings, a final decision will be made after rescue operations conclude.

It is considered inevitable as experts cautioned against proceeding with the original plans due to risks of further complications.

As far as the progress on the outlet tunnel is concerned, the excavation work was completed on a 20.435 kilometres stretch of the planned 23.980 kilometres length.

Work on only 3.545 kilometres is yet to be completed. Earlier, plans to shift the TBM engaged in the outlet tunnel for use in the inlet tunnel have been ruled out due to logistical issues.

Efforts are on to identify the factors that led to the collapse of the tunnel roof. The accident is attributed to several factors, one of them being seepage from the Mallala Theertham Waterfall.

The waterfall is located in the dense Nallamala forest some 20 kilometres away.

It is suspected that seepage from the waterfall might have exerted pressure on the tunnel’s structure, contributing to the roof collapse. The SLBC project aims to excavate a total of 43.930 kilometres between Domalapenta and Mannevaripalli.

TBMs were deployed from both ends to accelerate the work, but setbacks have delayed progress.