Domalapenta (Nagarkurnool): Fourth day into the rescue operation at Srisailam Left Bank Canal (SLBC) tunnel collapse site, the National Disaster Response Force (NDRF) teams, along with rat miners, on Tuesday finally reached the last point of the collapsed roof, where the eight workers have been trapped since Feb 22 morning. Until Monday, the rescue teams could not reach the last point and were stuck 40 metres away.
The teams utilised thermocol boats to navigate the challenging terrain to bring out at least some of the workers alive. If not, the rescuers will at least try to retrieve their bodies, officials at the site said. The teams are still facing obstacles, with heavy water and slush hampering the rescue efforts.
The eight workers are believed to be trapped in the last 50 metres in front of the tunnel boring machine (TBM), and no contacts could be established with them.
The project contractor, Jaiprakash Associates Ltd (JAL), initiated a dewatering operation to clear the water from the site in the hope of finding the missing workers.
Irrigation minister N Uttam Kumar Reddy, who was at the site, directed JAL to dewater the entire tunnel by Tuesday night or Wednesday morning. He also instructed NDRF, Navy and other agencies involved in the rescue to work in coordination and clear the final stretch of the tunnel. “The goal is to push the mud towards the tunnel entrance in order to locate the missing workers,” he said.
To aid in the effort, govt has roped in top 10 agencies, including Geological Survey of India and National Geophysical Research Institute, and private companies like L&T and Navayuga to identify vulnerable locations for debris removal.
The main challenge remains the accumulation of an estimated 10,000 cubic metres of slush from the 12th km of the 44-km-long tunnel. The slush has accumulated to a height of 10ft in some areas of the tunnel that is about 30ft high.
Attempts to remove the slush using pumping machines were abandoned due to the risk of clogging from debris. The only viable option left is using a conveyor belt which, however, faced technical difficulties, including loosening during use and limitations in reaching the farthest point. Officials are working to fix these issues, including extending the reach of the LoCo (tunnelling locomotive) to 13.5 km, allowing it to traverse up to 5ft of slush.
Meanwhile, TBM, a 200-metre-long machine weighing 250 tonnes, was severely damaged by the impact of gushing water, further complicating removal of debris.
With the focus squarely on rescuing the trapped workers, govt is prioritising efforts to clear the remaining obstacles and complete the dewatering process, officials at the site said.
Uttam, along with deputy chief minister Bhatti Vikramarka, and ministers Jupally Krishna Rao and Komatireddy Venkat Reddy, held a meeting with officials and representatives of the 10 agencies at the project site to take stock of the situation. Despite the efforts of over 10 agencies, the rescue teams have struggled to make any significant progress due to the severe conditions inside the 44-km-long tunnel.