'Layer upon layer of miracles': How Nepal flood survivors were rescued from tunnel

ByTessa Wong Asia Digital Reporter.

Key points

• Arnold Dix has been advising Nepal's hydropower authorities on how to dig through the blocked tunnel to Trishuli 3A Hydropower Station.
• The first hurdle was to locate the hydropower station, in a landscape rendered almost unrecognisable by the flood that has so far killed 1, 300 residents.
• Shortly after that, they pulled out Sanjaya Shah and Kabir Maharjan, alive.
• A tunnelling expert involved in the rescue operation at a blocked Nepalese hydropower tunnel has described to the BBC how they managed to reach survivors.
• But, buoyed by Friday's successful rescue, the team is now hopeful it will reach more survivors in time.

For context, a tunnelling expert involved in the rescue operation at a blocked Nepalese hydropower tunnel has described to the BBC how they managed to reach survivors.

Arnold Dix has been advising Nepal's hydropower authorities on how to dig through the blocked tunnel to Trishuli 3A Hydropower Station. It was one of a number of stations hit by last week's massive flash flood on the Nepal-Tibet border.

"It's like layer upon layer of layer of miracles" that they discovered two men on Friday, he stated, given the multiple challenges that they faced.

For context, the first hurdle was to locate the hydropower station, in a landscape rendered almost unrecognisable by the flood that has so far killed 1, 300 residents.

"I've never known a rescue operation where you had to look for an entrance of a tunnel that was previously up the hill, that was now underground. You can imagine the enormity of the avalanche, it completely buried the entrance, " remarked Dix. This person is the president of the International Tunnelling and Underground Space Association.

Using engineering techniques, old topographic maps, satellite imagery of the area after the disaster, video footage from helicopters and "anything else we could find on the surface of the mountain such as power poles", Dix and his team triangulated the probable position of the entrance and kicked off digging.

They discovered it – but the next challenge was to locate the survivors.

"We knew they would be up ahead, but we didn't know where exactly. So you just have to start digging in the right direction. And you listen out if you can hear anybody, " he remarked.

Rescuers had to obtain through a tunnel blocked entirely by mud and rocks – some bigger than cars – and had to apply explosives to clear the way, something they would "normally never do because of the risk of blowing up people and blowing ourselves up, " Dix noted.

He credited the Nepalese army for doing "a wonderful job" in managing the explosions with precision to ensure they would not destabilise the tunnel.

Meanwhile, they discovered it was still full of water.

Using excavators and pumping machines, Nepalese rescuers dug a series of trenches from the tunnel all the way to the river outside, so they could drain the water.

Finally, they had to dig a passageway, "a tiny tunnel the size of a person", through the debris at the top of the tunnel.

Meanwhile, the advantage of this location "is that you can employ the original tunnel's roof as your little tunnel's roof. Additionally, it mitigates risk of flooding, " Dix explained.

In the early hours of Friday morning, rescuers heard what they thought could be voices.

According to local reports, they called out "don't worry, we're here to rescue you" – and heard back a faint "okay".

But with dozens of individuals still thought to be trapped inside the tunnel, the work is far from over. Rescuers heading to 'Goldilocks zone'.

Dix estimated that they had dug regarding 60m from the entrance by now, and they would need to dig another 150m more to reach the hydropower station located deep inside the mountain.

Since if it did, "there would be all kinds of complications – anybody in the station could have been hit by rocks and mud or it could be flooded", rescuers are hoping that the debris from the flood did not reach the station. The team on the ground are still facing significant dangers.

"Up ahead, even now, we might run into water which would drown the people tunnelling, " Dix remarked. "And we additionally have the risk of another flood outside happening, so water could come from behind. So there's the risk of facing water on both ends."

"It's a major relief, that we are on the right track. And it gives us renewed energy that our thinking works. We have never done something like this before."

Dix remarked they are now heading towards what he called the "Goldilocks zone" which would be "more friendly to life".

This zone is at the uppermost level of the hydropower station where there is some space where survivors may be located.

"We obtained two residents out. If we were playing at a casino, some might say it's time to walk away, but we say game on, time to take on the house."

Taken together, the developments around ' Layer upon layer of miracles' : How Nepal flood survivors were rescued from point to a situation that is still moving, and the coming days should bring more clarity.