Fate of SLBC tunnel project now banking on military expertise

Former BRO Director-General Lt. Gen. (Retd.) Harpal Singh will join the mission as an honorary advisor, bringing decades of tunneling experience.

Hyderabad: The Srisailam Left Bank Canal (SLBC) tunnel project is set to resume work in July 2025, with support from military and engineering experts to tackle geological and environmental challenges.

The Indian Army has considered the deployment of Colonel Parikshit Mehra, a tunnel specialist from the Border Roads Organisation (BRO). He will be joining as a Special Secretary in the irrigation department. His expertise will be crucial in developing safe excavation strategies, particularly in navigating the shear zone — a heavily fractured and deformed rock region that poses the greatest risk to the project.

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To ensure a safe and efficient execution, fresh studies are being conducted to map the 44-km tunnel alignment, identify fault zones, water-bearing areas, and weak rock formations. High-resolution surveys will help determine possible bypass routes and reinforcement strategies needed to prevent further collapses.

Former BRO Director-General Lt. Gen. (Retd.) Harpal Singh will join the mission as an honorary advisor, bringing decades of tunneling experience.

In addition to this, the Indian Air Force, in collaboration with Pawan Hans, will commence aerial LiDAR and electromagnetic surveys on July 12, 2025, utilizing a Danish helicopter. These surveys will also ensure compliance with environmental regulations in the Amrabad Tiger Reserve.

Despite expert involvement, the project faces significant obstacles. The February 2025 collapse at the 14-km mark trapped eight workers is linked to a fault zone identified in 2022. About 9.5 km of tunnel boring in the 44 km long tunnel is still to be completed.

Reports from multiple agencies had already warned of weak rock formations and severe water leakage risks between the 13.88-km and 13.91-km marks. Water seepage, reaching 3,600 liters per minute, continues to threaten the project.

Earlier grouting efforts failed, and the rock formations proved too challenging for tunnel boring machines. Strict regulations in the tiger reserve limit new entry or exit points, complicating rescue operations and construction logistics.