Sunil Negi
Uttarkashi, 24 August
The Silkyara tunnel on the Yamunotri National Highway, part of the ambitious Char Dham all-weather road project, has once again confronted a monsoon-triggered breakdown, with a massive ingress of silt, water and muck blocking a portion of the under-construction bore and creating an emergency-like situation inside.
According to preliminary information from the site, one of the portals suffered internal failure during heavy overnight rain, leading to a tremendous quantity of silt and loose material sliding into the tunnel alignment. Pumping and muck-clearing operations are underway. NHIDCL engineers have temporarily suspended excavation work from the Silkyara end as a precaution.
As of Sunday evening, NHIDCL has not issued an official statement on casualties. Labourers working near the mouth were evacuated safely. The situation is under control but fragile due to continuous seepage, sources said.
The incident is a chilling reminder of the November 12, 2023 collapse, when a 60-metre stretch of the same 4,531-metre tunnel caved in at around 5.30 am, 270 metres from the Silkyara mouth, trapping 41 workers inside for 17 days.
They were trapped in a 2 km built-up stretch where concrete work was complete and survived on oxygen, water and food supplied through a 6-inch pipe. The rescue, which involved NDRF, SDRF, BRO, Indian Army, rat-hole miners and international tunnelling expert Arnold Dix, ended successfully on November 28 after drilling through 60 metres of debris with auger machines and manual mining.
A central probe panel had later flagged that the tunnel was being built through a geological shear zone – a fault in the fragile Himalayan strata – had no emergency exit despite being over 1.5 km long, and had insufficient exploratory bore-holes during the DPR stage.
Work had resumed only after six months, with NHIDCL mandating additional safety measures and starting dewatering and drift-tunnel excavation from the Barkot end to clear accumulated water and debris. The tunnel is still under construction and targeted for opening in early 2027.
Geologists warn that monsoon seepage is a common process in Himalayan tunnels, but prolonged suspension leads to large accumulation of water and silt inside, which can trigger secondary collapses.
Senior officials in Uttarkashi district said they are monitoring the situation and all safety protocols are being followed.
