Excavation crosses critical shear zone as Uttam Kumar Reddy directs faster work, additional equipment and strict safety measures to complete the 43.968-km tunnel
Hyderabad, Oct 2026 : The excavation of Telangana’s ambitious Srisailam Left Bank Canal (SLBC) tunnel has crossed a major geological hurdle, marking a significant breakthrough in the long-delayed irrigation project and opening the way for deployment of additional equipment to accelerate construction, Irrigation and Civil Supplies Minister N. Uttam Kumar Reddy said on Sunday.
The minister conducted a marathon review meeting with elected representatives and senior officials from the three districts of erstwhile Nalgonda to assess the progress of the SLBC tunnel and other key irrigation projects. The review focused on excavation, safety, equipment deployment, logistics and the government’s target of delivering water to the region by June 2028.
The SLBC project is expected to supply more than 30 TMC of water to the drought-prone upland areas of the region, which have faced persistent water scarcity for decades. Uttam Kumar Reddy said successful excavation through a precarious shear zone represented an important advance and praised officials, engineers and workers involved in the difficult operation.
He directed the project authorities and contractor to build on the recent progress by increasing equipment deployment, improving excavation cycles and maintaining stringent safety monitoring. He emphasised that the work must proceed according to a credible and closely monitored programme aimed at achieving the June 2028 water-delivery target.
The minister also stressed that the safety of workers operating more than 20 km inside the tunnel must remain paramount. Eight workers were killed during tunnel excavation in February 2025, making safety measures a key concern as construction enters a critical phase.
According to the project team, excavation had advanced by around 700 metres over the previous five to six months. Of this, nearly 450 metres had been excavated from the outlet and another 250 metres from the inlet. The progress included the difficult passage through the major shear zone, where geological instability had posed substantial technical and logistical challenges.
The 43.968-km main tunnel is now around 79 per cent complete, with approximately 9.1 km of excavation remaining.
Colonel Parikshit Mehra, an Indian Army tunnel expert leading the tunnel operations, explained that excavation at the inlet had been deliberately slowed during the initial months because of weak geological formations, rock bursts and concerns over worker safety. The diversion around the location where the tunnel-boring machine had become stuck had taken the excavation face through particularly difficult ground conditions.
To safely negotiate the unstable stretch, engineers installed 140-mm seamless pipes to create an umbrella canopy that provided protective support ahead of the excavation face. Reinforced ribs, staged excavation, probe drilling and additional support systems were also introduced to manage geological risks.
The project team said rock conditions were now improving, allowing workers to gradually return to more normal excavation conditions deep inside the tunnel.
Uttam Kumar Reddy called for the momentum to be sustained through timely deployment of machinery and better logistics. The team reported a current combined excavation advance of about eight metres per day, while the sustained rate remained between seven and 7.5 metres daily. On one or two days, progress had touched 10 metres.
A three-arm drilling boomer is already operational at the outlet, where excavation is progressing close to the required pace. Another three-arm boomer is expected to arrive at the inlet in October. Electric loaders and advanced excavators are also being used to support excavation and material-handling operations.
A locomotive ordered from Germany is expected to arrive by the end of October. Its deployment is expected to improve the transportation of excavated material and reduce delays in the construction cycle.
Removal of excavated material over distances of up to 21 km remains one of the major operational constraints. When muck removal falls behind excavation, material begins accumulating inside the tunnel, eventually forcing work at the excavation face to stop until the backlog is cleared.
The project team reported that a construction cycle that earlier required nearly 48 hours had now been reduced to between 20 and 24 hours. With additional equipment, improved material transportation and faster muck removal, officials expect the cycle to be reduced to around 10 hours. This is expected to significantly accelerate excavation from late October or early November.
Uttam Kumar Reddy directed officials to maintain close monitoring of progress and safety while ensuring that the recent breakthrough translates into sustained daily excavation. He said the government’s objective was to complete the remaining work efficiently and safely so that the long-awaited irrigation benefits could reach the parched upland areas within the targeted timeframe.
MPs K. Raghuveer Reddy and Chamala Kiran Kumar Reddy, MLAs Mandula Samel, K. Jaiveer Reddy, Vemula Veeresham and Anil Kumar Reddy, MLC Shankar Naik, Irrigation Secretary E. Sridhar, Engineer-in-Chief O.V. Ramesh Babu, and Collectors of Suryapet, Nalgonda, Yadadri-Bhongir and Mahabubabad districts attended the review meeting.
