Uttarakhand Tunnel Collapse: Rescuers activate Plan B, to go for 86-metre vertical drilling

Neeraj Mohan

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Silkyara (Uttarkashi), Nov 25

Faced with persistent technical obstacles impeding the US-made horizontal drilling machine’s progress beyond 46.8 metres, the rescue operation encountered another day of setbacks on Saturday, forcing the rescuers to work on Plan B — vertical drilling to expedite the rescue of 41 workers trapped in the partially collapsed under-construction tunnel since November 12.

Landline facility set up for trapped workers

For the past one week, machines designated for vertical drilling have been stationed near the tunnel. Now, for the first time, these machines are being mobilised, with officials orchestrating their transport to the hilltop for drilling into the mountains up to 86 metres — a technique commonly employed in deep-sea excavation. An Oil and Natural Gas Corporation Limited (ONGC) drilling team assessed the site on November 20. The authorities were of the view that vertical drilling would take approximately a week to penetrate the rocks.

A drilling machine from Rishikesh is on the way to the hilltop through a road constructed by the Border Roads Organisation (BRO) and is expected to be operational soon. The BRO has completed the construction of the approach road for vertical drilling. Besides, an approach road for the ONGC is under construction based on geological surveys conducted by the corporation.

Horizontal drilling came to an abrupt halt when augers broke upon striking steel girders, leaving broken pieces lodged inside pipes. Technical experts have diligently worked since Friday morning to extract these, with only two augers successfully removed, while six remain entangled, necessitating a meticulous extraction process. Consequently, the authorities have activated Plan B, involving vertical and directional drilling.

Meanwhile, officials will continue work on the horizontal drilling as well to cover the remaining 10-12 metres. Efforts are underway to cut the girders, and there is a possibility that the broken iron will be removed by Sunday morning. Subsequently, workers may commence manual drilling to cover the remaining distance of 10-12 metres. A plasma cutting machine has been brought from Hyderabad to cut the iron stuck in the machine. Since Thursday, the rescuers have grappled with an array of challenges.

Efforts on to remove broken machine parts

• Horizontal drilling came to an abrupt halt when augers broke upon striking steel girders, leaving broken pieces inside pipes
• Experts have diligently worked since Friday morning to extract these, with only two augers removed, while six remain entangled