Nepal rescuers find a cool air pocket 350 feet into a silted Chilime tunnel

Nepali Army soldiers crawling through a silt-choked tunnel at the Chilime hydropower project felt a gust of cool air on Saturday. They were about 350 feet in. They yelled into the gap and heard an echo. Officers concluded that a pocket of air lay ahead, near the upper levels of a five-floor underground powerhouse where six workers are believed to have been when the Trishuli River arrived as mud.

The discovery does not mean those six men are alive. It means the geometry of the wreck still holds space that is not packed solid with slurry. Crews have fully cleared about 200 feet of the 820-foot tunnel that leads to the hall. A higher route has been pushed farther. One passage in the underground network slopes upward and connects to the top floor of the powerhouse. That is the line the army is following.

Chilime sits on the Trishuli in Rasuwa district. In late August a glacial collapse sent a wave of water, rock and debris down two Himalayan valleys. The official death count across Nepal and neighbouring Tibet passed 1,300. More than 4,000 people were listed missing in the first week. Hydropower plants, built into the same river corridors that produce Nepal's export electricity, took a concentrated blow. Tunnels filled. Halls vanished under silt deep enough that engineers used satellite images to find the outlines of buildings they had walked through days earlier.

Hope at these sites has already been paid for. On 4 September, nine days after the flood, rescuers at the Upper Trishuli 3A plant pulled two men out alive. Sanjay Sah, a 30-year-old mechanical foreman from Saptari, and Kabir Maharjan, a 45-year-old mechanical supervisor from Kathmandu, had survived in an air-filled chamber. Sah raised a hand toward a camera as he was carried out on a soldier's back. Maharjan left on a stretcher. A third man, a mechanical engineer, was recovered dead the same day. More than 40 other workers were thought to have been inside that tunnel when the river hit.

The 3A rescue is why Saturday's gust at Chilime matters. It showed that a sealed hydropower cavern can keep air, and that men can last more than a week if the chamber does not flood to the roof. It also showed how slow the work is. Australian tunnel specialists advised the 3A effort. Indian and Chinese technical teams have been on site. Heavy equipment operators cut through a mixture that behaves like wet concrete. Progress is measured in tens of feet per shift.

Home Minister Sudan Gurung had earlier said rescuers at 3A had reached the crown of a tunnel and begun pumping air while they dug. That sequence is now the template: find a void, feed it air, then cut a hole large enough for a stretcher. At Chilime the void has only been inferred from a breeze and an echo. The next hours will decide whether the inference holds.

Nepal has spent two decades turning Himalayan rivers into a power-export business. India is the main buyer. The same geology that makes the rivers steep makes the valleys unstable when a glacier fails. Plant operators submitted lists of missing workers that, in the first week, ran past 900 names across multiple sites. Those lists have been revised as bodies and, rarely, survivors come out. The six names at Chilime are the ones the army is working toward now.

Saturday night the crews were still in the tunnel. Cool air is not a voice. It is the first physical sign that the upper floors of the Chilime hall may not be a solid block of mud. The men who felt that gust will keep cutting toward the echo.