Ignored Warnings? 2020 Report Flagged Fault Zone In Telangana's SLBC Tunnel, Now Site Of Tragic Collapse Trapping Workers

The collapse of a section of the Srisailam Left Bank Canal (SLBC) Tunnel in Telangana on 22 February, trapping eight workers, has raised serious questions about prior warnings that may have been ignored. A report commissioned by Jaiprakash Associates Ltd—the company awarded the tunneling contract in 2005—had flagged a "fault zone" in the tunnel as early as January 2020, as reported by The Indian Express.

Early Warning Ignored?

Amberg Tech AG, a tunneling survey firm, had identified a high-risk stretch between 13.88 km and 13.91 km from the tunnel’s mouth in its Tunnel Seismic Prediction (TSP) – 303 Plus report.

The findings pointed to weak rock strength, a water-bearing zone, and the presence of sheared rock mass, indicating a high likelihood of collapse.

Rescue officials now confirm that the tunnel collapse occurred near this very stretch. “The roof caved for three meters around the fault zone,” said a senior official involved in the ongoing rescue operations, as quoted by The Indian Express.

Unanswered Questions

Despite the report's alarming conclusions, Jaiprakash Associates Ltd and Amberg Tech AG have declined to comment, citing confidentiality. It remains unclear whether the Telangana Irrigation Department was informed about the findings.

Geologists, however, suggest that while rock conditions remain unchanged over four years, increased water seepage could have worsened the tunnel's stability.

Challenges in Rescue Operations

The rescue mission, already over 13.5 km into the tunnel, faces repeated flooding, making operations dangerous and intermittent. The Tunnel Boring Machine (TBM) is now stuck at a dead-end, with no signs of the trapped workers.

A separate research paper on the SLBC project further highlights major flaws in planning.

Due to the tunnel's location inside a Tiger Reserve Forest, no borehole drilling or physical geotechnical investigations were conducted before excavation. The project proceeded without firm data, leaving workers vulnerable to natural hazards.