Uttarakhand Tunnel Collapse: All 41 workers rescued, as ‘rat-hole mining’ succeeds

All 41 workers have been rescued from a collapsed tunnel on Tuesday after being trapped for 17 days in Uttarakhand.

The collapsed Silkyara tunnel in Uttarakhand was finally breached, an official said on Tuesday, as rescue teams drilled through rocks and debris using ‘rat-mining’ techniques on Tuesday.

Rescue workers are all set to pull the trapped workers out of tunnel one by one to safety, in positive news.

The official confirmed to PTI that the drilling operation has been successfully completed.

What is rat-hole mining?

The term ‘rat-hole’ refers to a narrow pit dug into the ground, enough for one person to pass through. Generally, this technique is used in coal extraction in narrow places.

The ‘rat-hole’ miners in Silkyara are digging these ‘rat holes’ to manually extract the rubble from pipe. These rat holes can be dug both vertically and horizontally.

Rat-hole mining is broadly classified into two categories, side-cutting and box-cutting.

In the side-cutting procedure, narrow tunnels are dug on the hill slopes. Box-cutting involves digging a vertical rectangular pit first, 100 to 400 feet deep, and then digging horizontally as and when required to better reach the target.

Hazardous conditions, which may lead to accidents, injuries and even deaths have caused regulatory concerns around the world and India has also attempted to strictly regulate this method, but the practice still persists due to economic factors and the absence of viable alternatives, such as what happened in Silkyara.

NDRF to the rescue

National Disaster Response Force (NDRF) and State Disaster Response Force (SDRF) personnel, equipped with ropes, lights, and stretchers, were seen at the entrance of the Silkyara tunnel, as rescuers negotiate the final 2-3 metre stretch, which is said to be tricky with soft debris and slush to deal with.

NDRF officials will traverse to the other side of the collapsed tunnel through a pipeline, once on the opposite side, they will communicate with the trapped individuals to assess their condition and commence a safe evacuation.

Ambulances have also been placed on standby near the entrance and a green corridor has been established, streamlining the path for ambulances to swiftly provide any medical assistance.

The process of pulling the trapped workers out, one at a time on wheeled stretchers through a pipe 90 cm (3 feet) wide, would take a couple of hours, reported Reuters.

The tunnel is part of the $1.5 billion Char Dham highway, one of Prime Minister Narendra Modi and the BJP’s most ambitious projects, aimed at connecting four Hindu pilgrimage sites through an 890 km network of roads.

Rescue efforts have been ongoing in Uttarakhand’s Uttarkashi for 16 days to free the workers trapped in a tunnel, with the multiple agencies encountering obstacles that halted the operation a number of times.

A portion of an under-construction tunnel from Silkyara end collapsed on November 12 trapping 41 workers underneath. The cause of the cave-in could be attributed to landslides in a region prone to earthquakes and floods.

The vertical drilling of the hill in Silkyara commenced on Sunday afternoon, with around 110 meters of the hill to be dug out for the rescue of the trapped workers.

In the first 12 hours of the rescue mission, the vertical drilling machine made good ground and drilled 20 meters into the ground, leaving 86 meters that was negotiated today.

The initial plan was to rescue workers through horizontal drilling with the expertise of international tunnelling experts.

However, the operation had to be stopped on November 24 when the auger drill blades broke.

Agencies were exploring multiple plans on the 16th day of the rescue operations.

The trapped men are being provided fresh cooked food, water and medical supplies through a small 6-inch tunnel inserted into the rubble.

The 41 trapped workers are to be airlifted out of the collapsed tunnel.

The vertical drilling machine was brought in after the American auger machine was unsuccessful in the horizontal drilling of the tunnel, and eventually got stuck and broke off in the metal grinder in the middle of the operation. Here are the top points from the rescue mission.

However, the process of removing the parts of the auger has been completed, and the drilling and pushing work will now begin.

This was informed Monday morning by Uttarakhand Chief Minister Pushkar Singh Dhami. The CM further stated, ‘The auger machine has been taken out completely…Drilling and pushing work will start and we hope that the work is completed at the earliest,’ reported ANI.

A plasma machine was flown in from Hyderabad to cut the auger machine out through the tunnel side.

Robotics experts were also on site at the rescue operations to monitor the mental well-being of the trapped workers.

Indigenous technology was used to provide internet service, monitor the mental health of the workers and detect gas buildups.

A delegation led by Principal Secretary to Prime Minister, Pramod Kumar Mishra took stock of the ongoing efforts and spoke to the workers’ families.

A Border Roads Organisation official said, ‘Frames of 800 mm diameter pipes have been prepared. We will move ahead by half a metre to one metre gradually. If all goes well and no obstacles are encountered a 10-metre stretch can be covered in 24-36 hours.’

The team of 12 rat hole miners arrived from Delhi and Jhansi to enter the tunnels and dig manually.

Who are the men inside?

The workers include fifteen from Jharkhand, eight from Uttar Pradesh, five each from Odisha and Bihar, three from West Bengal, two each from Uttarakhand and Assam, and one from Himachal Pradesh

Not involved in construction, says Adani group

The Adani group on Monday said it has no direct or indirect involvement in the construction of the Silkyara tunnel. 

In a statement, an Adani group spokesperson said the conglomerate does not own or hold any share in the company involved in the construction of the tunnel.

‘We clarify with utmost emphasis that the Adani group or any of its subsidiaries has no direct or indirect involvement of any kind in the tunnel’s construction,’ it said. ‘We also clarify that we do not own or hold any shares in the company involved in the tunnel’s construction.’