The death toll in the methane explosion inside the under-construction tunnel of the Teesta Stage-VI Hydel Project in Bengal’s south Sikkim rose to 13 on Wednesday after another body was recovered, while 12 workers remained missing, officials said.
Event Context
Rescuers have to enter the tunnel wearing self-contained breathing apparatuses, which help maintain a steady supply of oxygen during long-haul rescue operations. Each apparatus weighs around 15 kg.
Player Focus
People aware of the developments at the accident site said the search and rescue operations had to be suspended for some time because water and mud had accumulated at the site. It, however, resumed after a few hours.
Team Analysis
Rescue teams battled poisonous gases, mud and poor visibility to search for survivors. “Conditions are very bad inside. It is pitch-dark and hot inside. The tunnel is full of poisonous gases such as methane and carbon monoxide. The floor of the tunnel is full of mud and our legs were frequently getting stuck,” said a member of the rescue team of Coal India Limited.
A total of 25 workers, who were working inside Adit-3 of the 15-km-long tunnel in Namchi district, connecting the barrage at Siwarni with the powerhouse at Tarkhola in South Sikkim, were trapped on Monday. “The explosion was triggered by a possible methane gas leak. The methane gas was probably trapped in a pocket in the rock which was being drilled by the tunnel boring machine. When the machine hit that pocket, the gas leaked and triggered the explosion,” a National Hydroelectric Power Corporation (NHPC) official, requesting anonymity, said.
Superintendent of Police of Namchi Sonam D Bhutia said, “We have recovered one more body on Wednesday taking the death toll to 13. At least 12 persons are still missing. Rescue teams from the National Disaster Response Force (NDRF) and Coal India Limited are still working at the site.”
Members of the Coal India Limited (CIL) rescue team claimed to have spotted at least eight more bodies inside the tunnel on Tuesday. The bodies are yet to be recovered. The Namchi district administration could not verify the claims till Wednesday evening.
“Our gas detectors are equipped to detect and measure the levels of four gases – hydrogen sulphide, oxygen, methane and carbon monoxide. During the rescue operations we detected high doses of methane and carbon monoxide. Usually, a site is evacuated if the Lower Explosive Limit (LEL) of these gases touches 20%. But the levels of carbon monoxide and methane are much higher in the tunnel, making it difficult to work,” said an official working at the site.
Rescuers who went inside said it was very difficult to walk as their legs were getting stuck in the mud, and every time they had to take the support of something to pull their legs out, making the rescue operations more strenuous and difficult.
“We have deployed earth movers. Our engineers are repairing the damaged pipes so that water and mud could be pumped out and rescuers could go in. The rescuers are wearing masks and 15-kg breathing apparatuses fitted with oxygen cylinders to go inside the dark tunnel and look for survivors and bodies,” said an official.
Match Outlook
“During tunnel excavations a lot of mud, silt and water comes out. They are pumped out. But as the blast has damaged the equipment and pipelines, the mud and water couldn’t be pumped out and hence the floor has become muddy and water has accumulated in pockets, hampering rescue operations,” said another official.
