Why the Telangana tunnel rescue is so challenging? A race against time to save trapped workers

Rescue operation underway to extricate eight persons trapped inside the tunnel (PTI)

Three days after a portion of the Srisailam Left Bank Canal (SLBC) tunnel in Telangana's Nagarkurnool district collapsed, the rescue mission to save eight trapped workers remains an uphill battle. A multi-agency operation is underway to clear the locomotive track inside the tunnel and transport essential equipment for further rescue operations.

What happened?

The incident occurred on Saturday morning when a section of the tunnel collapsed approximately 13.5 kilometres inside. The sudden cave-in trapped eight men under a thick layer of mud and debris. Since then, water seepage and slush have blocked rescuers from reaching the trapped workers.

The trapped workers include Manoj Kumar (Project Engineer) and Srinivas (Field Engineer) from Uttar Pradesh; Sandeep Sahu, Jataks, Santosh Sahu and Anuj Sahu from Jharkhand; Sunny Singh from Jammu & Kashmir; and Gurpreet Singh from Punjab.

The collapse came just four days after construction resumed following a lengthy hiatus, adding urgency and frustration to the operation.

Who is involved in the rescue?

The rescue mission is a massive, multi-agency effort involving the Indian Army, National Disaster Response Force (NDRF), State Disaster Response Force (SDRF), experts from Singareni Collieries and NHIDCL. Besides, six rescuers from the successful Silkyara tunnel rescue mission in Uttarakhand have also joined in for the rescue.

Despite these combined efforts, no contact has been established with the trapped workers so far.

What makes this rescue op so challenging?

The rescue operation inside the SLBC tunnel has become increasingly challenging due to deteriorating conditions within the tunnel. A major hurdle is the continuous heavy seepage of water, which has led to the formation of thick slush, making any movement inside the tunnel nearly impossible. Visibility is another significant obstacle. NDRF's 10th Battalion Commandant Prasanna Kumar told The Indian Express that rescuers are contending with nearly 11 feet of waterlogged mud, which has completely obscured their view.

Adding to the difficulty is a solid wall of mud that even Navy commandos were unable to breach due to the lack of specialised equipment suited for these conditions. Inside the tunnel, rescuers have also encountered twisted metal debris and large concrete blocks, creating hazardous conditions and increasing the risk for the teams attempting to clear the path. Furthermore, the collapse has destabilised natural rock structures, triggering unpredictable flows of water and mud, which have further complicated the rescue effort.

In response to these challenges, rescue teams have deployed various techniques and specialised equipment, including probe scopes and sonar devices to assess the conditions within the tunnel. The rat-hole miners, who were brought in for their expertise, were also ultimately unable to operate effectively due to the waterlogged environment.

All the techniques have hit roadblocks due to the overwhelming presence of water and debris. According to Kumar, "Right now, there is no existing technology that can help us clear this slush fast enough."

What’s the current plan?

The current focus of the rescue operation is on clearing the locomotive track inside the tunnel to facilitate the transportation of equipment needed for dewatering and slush removal. Simultaneously, efforts are underway to carve out a path for earth-moving machines to access the collapse site more effectively.

Rescuers believe that reaching the front section of the boring machine is critical, as it is likely where the trapped men are located. However, this area remains buried under a dense layer of mud and debris, making access extremely challenging.

Telangana’s Irrigation Minister, Uttam Kumar Reddy, has acknowledged the difficulties, stating that the challenging terrain has limited the use of heavy machinery. Experts suggest that it could take several more days to clear the slush and debris using tunnel boring equipment.