Below is a short summary and detailed review of this video written by FutureFactual:
India's Himalayan Tunnels: Silk Yarra Collapse, Rescue, and the NATM Zojila Challenge
Summary
In late 2023 a new road tunnel in Uttarakhand, India collapsed, trapping 41 workers for more than two weeks. The escape was orchestrated through a multi-pronged rescue plan led by the International Tunnelling and Underground Space Association president Arnold Dix, combining vertical surface drilling, a side TBM approach, and manual digging after an auger drill failed. All workers were eventually freed with no serious injuries, but the incident underscored systemic risks of tunnelling in the Himalayas.
A parallel near-miss occurred in 2025 with a rail tunnel in the same region, highlighting the region's tectonic and hydrogeological complexities. The video also explains the broader infrastructure push in the Indian Himalayas, including the Zojila Tunnel in Ladakh, and outlines the New Austrian Tunnelling Method, ventilation shafts, and the planned long-term improvements that aim to deliver safer, year-round mountain roads.
Background and Context
The Silk Yarra Collapse
In November 2023 a 4.5-kilometre road tunnel under construction collapsed 270 metres from the southern portal at Silk Yarra. With the tunnel not yet joined in the middle, 41 workers were trapped. The only exit was a small emergency tunnel providing air, food, and water. An emergency rescue plan was assembled, and an auger drilling method was deployed alongside parallel efforts from different teams. The auger broke down just short of the target, and miners completed the last stretch using hand drills. After 17 tense days, all visible workers were rescued, marking a dramatic turn but also exposing the danger of Himalayan tunneling.
Investigation and Lessons
Official reports pointed to poor workmanship and lax tunneling practices, with previous issues not adequately addressed. Arnold Dix observed 21 prior collapses when first entering the Silk Yarra portal, illustrating a pattern rather than an isolated failure. The incident emphasized the need for adaptable methods and robust risk management when working in seismically active and hydrogeologically variable rock formations.
Beyond Silk Yarra: Regional Challenges and New Routes
Around 200 kilometres southeast, a rail tunnel in the same state nearly failed in 2025 when a surge of groundwater threatened potential flooding or collapse. The geology of the Himalayas features shear zones and rock heterogeneity that complicates tunneling. The Atholl Tunnel, a 9-kilometre road tunnel bypassing Rotang Pass, demonstrates both potential gains and significant water inflow challenges, including thousands of litres per minute in parts of the tunnel. These examples set the stage for ambitious projects such as the Zojila Tunnel in Ladakh, which at 13 kilometres would be India’s longest tunnel and aims to cut travel time to about 15 minutes year-round by using the New Austrian Tunnelling Method (NATM).
Technology, Construction Methods, and Scheduling
Mega Engineering and Infrastructures has employed NATM, which uses surrounding rock as support and emphasizes continuous ground monitoring. The project also includes cut-and-cover sections and vertical ventilation shafts up to 5,100 metres in height in the main route. A pilot tunnel of 7.5 metres diameter is under construction, with breakthroughs achieved in mid-2025. Despite these advances, the original December 2026 completion target has shifted by about four years due to ongoing challenges. The Himalayas’ unforgiving terrain and tectonics demand a flexible, safety-forward approach to tunneling.
Impact and Outlook
These events are shaping India’s strategy for large-scale mountain infrastructure, balancing the promise of safer, faster travel with the realities of geological uncertainty and seismic risk. The narrative closes with a reminder of the human dimension, including mental health considerations in construction and the need for support networks for workers on demanding projects.
