Experts advise caution due to instability fears in the SLBC tunnel
Hyderabad: The state government has decided to “take a middle path” as the SLBC tunnel, where a collapse occurred on Saturday trapping eight workers, “is still unstable” and on Tuesday pushed on with “exploratory” expeditions. The various teams entering the tunel were nowhere near mounting an actual attempt to locate the workers, who were separated from the rescuers by copious flows of water and slush.
Irrigation minister N. Uttam Kumar Reddy said the experts were of the opinion that “we should wait for a day or two for the conditions to stabilise. Having taken everyone’s opinion, we have chosen a ‘middle path’ of sending teams into the tunnel to check on the conditions where the collapse occurred.” The information gathered by them can be used to plan for the next stage of operations.
The minister earlier chaired a high-level review of the conditions inside the tunnel, at the SLBC inlet site in Domalapenta on Tuesday,
It was learnt that during the review, experts made it clear that the situation in the collapsed section was volatile and any attempt to remove the silt could result in another collapse, which could be dangerous. Any attempt to either tamper with the destroyed tunnel boring machine (TBM) that is buried under silt, or to remove the silt itself, could trigger another event, the experts are learnt to have said at the meeting.
The collapse, Uttam Kumar Reddy told reporters, “is the most serious, complicated, and complex tunnel collapse accident ever in India.” He, however, declared that “the government is committed to make every effort to rescue the eight workers trapped inside the tunnel.”
“During the last three days, we have called everyone who has ever taken part in any tunnel rescue in the country. There has never been such an accident in India.”
Uttam Kumar Reddy said that as part of trying to find a solution to reach the section of the tunnel where the workers are trapped – some 13.9 km into the structure – he spoke with General Harpal Singh, who heads the Indian Army’s Border Roads Organisation which has vast experience in working in extremely difficult circumstances, and in tunneling operations.
“He said he will be coming tomorrow (Wednesday) following my request to do so. He said he has not seen such a complicated and complex accident and assured all possible help,” Uttam Kumar Reddy said.
Unlike in other tunnel accidents like the one in Uttarakhand where there was an exit and an entrance, SLBC goes just one way, Uttam Kumar Reddy pointed out, which makes the rescue task that much more difficult.
It may be recalled that after extensive discussions on Monday, all the teams involved in planning the rescue had concluded that the instability inside the tunnel where the collapse occurred could be very dangerous and recommended that all operations be halted until the situation stabilised.
On Tuesday, after detailed talks and taking inputs on the potential risks if any rescue operation is mounted as it will involve beginning the removal of tonnes of mud that could result in a fresh collapse, the decision was taken to limit the activity to reassessing the conditions, and the work needed to begin the actual rescue efforts.
Uttam Kumar Reddy said the serious challenges include a combination of water and silt, with the silt reaching a height of 15 to 20 feet near the tunnel boring machine where the missing workers are believed to be stuck, and these conditions exist for about 200 metres making it a dangerous environment. “The entire mass is moving towards the exit,” he added.
Adding to the woes is the increasing water flow, that is reaching up to 5,000 litres a minute. “Despite these challenges, our personnel are displaying extraordinary dedication, working continuously without rest. We are deploying high-powered pumps to remove the floodwater, but the conditions remain extremely difficult,” he said.
Meanwhile, a team of NDRF personnel, along with a team of ‘rat miners’ who worked previously in the Uttarakhand rescue, late in the evening, managed to reach the TBM but were forced to retreat because of lack of enough air, and extreme heat as the ventilation duct that pumps air, was broken and bent when the accident occurred.
Uttam Kumar Reddy reiterated that the SLBC tunnel was a crucial project that was neglected for ten years under the previous BRS government.
“This is one of the longest tunnels in the world, without any intermediate outlets spanning 45 kilometres, out of which 35 km has been completed. Once finished, this project will provide a lifeline to the Nalgonda district, transforming it into a green belt and offering a permanent solution to fluoride contamination,”he explained.
He said the unfortunate incident should not overshadow the importance of completing the project. “Despite this setback, we remain committed to ensuring the safe completion of SLBC and delivering its benefits to the people of Telangana,” he said.
There will be another review meeting with all the agencies on Thursday morning when further decisions may be taken.
