Twin Tunnel Tragedies: Rescue Challenges in Uttarakhand and Telangana Collapses

(Source – Indian Express, Section – Express Network- Page No. – 10)

Topic: GS3 – Disaster Management

Context

Two tunnel collapses occurred in India—one in Uttarakhand’s Silkyara tunnel trapping 41 workers (later rescued) and another in Telangana’s SLBC tunnel trapping eight workers, with rescue operations underway amid greater challenges.

Analysis of the news:

Background

• Two major tunnel collapses have occurred in India within a short span: the Silkyara tunnel collapse in Uttarakhand’s Uttarkashi district (November 2023), where 41 workers were trapped for over 400 hours, and the Srisailam Left Bank Canal (SLBC) tunnel collapse in Telangana, trapping eight workers.

• Although rescue operations are underway in Telangana, experts indicate it presents greater challenges compared to the Uttarakhand incident.

Key Differences in Rescue Operations

1. Water and Mud Seepage:

• Uttarakhand (Silkyara): No water or mud seepage, allowing longer survival chances and easier drilling operations.

• Telangana (SLBC): Presence of a thick mud-water mix poses a major hazard. Survival chances reduce significantly as water can be fatal within 20 minutes.

2. Space Availability:

• Silkyara Tunnel: Trapped workers had two kilometers of movement space, which improved survival conditions.

• SLBC Tunnel: Workers are trapped at the dead end, reducing oxygen availability and complicating rescue approaches.

Differences in Rescue Techniques

1. Use of Rat Hole Miners:

• Uttarakhand: Rat hole miners played a crucial role by manually digging through the remaining debris after drilling machines failed.

• Telangana: Rat hole miners are not feasible due to the water-logged environment, and there’s a lack of technology suitable for drilling through the thick slush.

2. Machinery and Drilling Approaches:

• Silkyara Rescue: Auger machines and vertical drilling were used, despite repeated breakdowns. Manual digging by miners eventually succeeded.

• SLBC Rescue: Vertical drilling is challenging due to a 400-meter-high top surface, and drilling could damage aquifers, increasing the risk of water inflow and endangering lives.

Geological and Terrain Challenges

1. Geological Composition:

• Silkyara Tunnel: Located in the Shivalik ranges with fragile geology but relatively accessible at 200 meters from the portal.

• SLBC Tunnel: Terrain complexity increases due to higher top surface depth (400 meters), making vertical drilling risky.

2. Debris Characteristics:

• Silkyara: Debris included steel, rocks, and boulders, requiring gas torches and manual digging.

• SLBC: Thick slush mixed with mud and water makes conventional excavation techniques ineffective.

Conclusion

• The Telangana SLBC tunnel rescue is inherently more complex than the Silkyara operation due to water ingress, limited movement space, and challenging geological conditions.

• Innovative technology and coordinated efforts are essential to overcome these difficulties.

• The incidents also underline the need for stricter safety protocols and advanced preparedness for tunnel construction projects across diverse terrains in India.

Practice Question: Discuss the challenges faced in tunnel rescue operations in India with reference to the recent collapses in Uttarakhand and Telangana. Suggest measures to enhance safety and efficiency in such rescue missions. (150 Words /10 marks)