Australian underground expert Arnold Dix summoned as a consultant by the Indian government, has been spending days and nights outside an under-construction road tunnel in Uttarakhand, where 41 workers have been trapped for more than a fortnight now. Dix describes this tunnel as the "toughest" tunnel rescue operation he's ever encountered.
The Silkyara tunnel is part of a $1.5bn 890km-long flagship Char Dham project connecting key Hindu pilgrim sites through two-lane paved roads in the Himalayan state. Efforts to clear the 60m blockage and create an exit passage for trapped workers using crawl-out pipes, have faced numerous roadblocks, including the breakdown of the main drilling machine.
"I think this is the toughest not purely for technical reasons. This is tough because the stakes are very high. No one has been injured and we have to make sure every person inside comes out fine," Mr Dix said.
Bernard Gruppe, a German-Austrian engineering consultancy hired by the Indian company building the tunnel, had said in August that since "the start of tunnel driving, the geological conditions have proved to be more challenging than predicted in the tender document".
It is not clear why an "escape passage" approved for the tunnel in 2018 had not been built until the time when the tunnel collapsed.
The Himalayas are the world's youngest mountain range, home to the highest peaks, formed some 45 million years ago as a result of the collision and folding of two continental plates. The upward climb of the Himalayas comes with seismic activity - in other words, it's an earthquake-prone region.
Geologists say many of the rocks in the northern Himalayas where Uttarakhand is located are sedimentary rocks - phyllite, shale, limestone, quartzite - which form when loose sediments of the Earth's surface become compressed and bond together.
There are two main road tunnels in the project: the Silkyara tunnel and a shorter 400 metre tunnel in Chamba. Apart from that, there are tunnels being bored for railways and hydropower, including a dozen over 110km (68 miles) for a 125km railway link. Then there are tunnels for a number of hydropower projects - there are 33 such state-run hydro projects in operation, and another 14 being built, according to official documents.
Environmentalists, such as Mr Dhyani, advocate for a "terrain-specific approach" in all tunnel construction projects, emphasizing the unpredictable reactions of geology in different regions.
Authorities now admit that timelines provided for the rescue of 41 men could change due to "technical glitches, the challenging Himalayan terrain, and unforeseen emergencies".
This, for a road, which was designed to offer all-weather connectivity, reducing the sometimes snow-affected stretch from 25.6km to 4.5km and slashing travel time from the current 50 minutes to a mere five minutes.
Ironically, the prolonged wait to rescue the trapped workers building the road is turning out to be a distressing ordeal. "This is a serious wake up call for all of us," says Mr Dhyani. (with inputs from BBC)
