17 days, 57 metres of digging: Uttarakhand tunnel rescue operation, in numbers

In the final leg of the rescue operations, at least 6 rat-hole miners arrived from Delhi and Jhansi to enter the tunnels and dig manually. Additional Secretary, Union Ministry of Road Transport and Highways, Mahmood Ahmed said that simultaneously, work of vertical drilling was also on at a fast pace during the final hours.

Here is the story of Silkyara tunnel collapse, in numbers:

1. 01

   Number of workers trapped: 41

   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 – the men trapped inside the Uttarkashi tunnel may have come from different states, but what united them was the need to venture out in search of a livelihood. The Indian Express spoke to their families, as the authorities rallied to rescue them from the depths of the tunnel.

2. 02

   Number of days they have been trapped: 17

   On November 12, Rajeev Das, a construction worker, heard a colleague shouting. A part of the tunnel where he had been working had collapsed, trapping his colleagues inside. Soon the State Disaster Response Force is informed and the rescue operation began.

3. 03

   Number of agency teams on site: 12

   A dozen agencies from the state and the Centre, regular coordination between the backroom and the ground, and experts from myriad fields collaborating to solve a single puzzle — that’s what it took for rescuers to get the men out from Uttarkashi tunnel.

   These included the NDRF, SDRF, BRO, National Highways & Infrastructure Development Corporation Ltd, Navayuga, Oil and Natural Gas Corporation, Tehri Hydro Development Corporation, Satluj Jal Vidyut Nigam, Rail Vikas Nigam Limited, Trenchless Engineering Works, as well as the state and district authorities, and the Army and Air Force.

4. 04

   After a five-point plan, a sixth and final attempt with manual drilling

   The rescue operation had a five-point plan in place by day 10, which involved Horizontal boring from Silkyara end using American machine, digging a 1.2 m wide hole vertically, from above, horizontal micro-drilling from the left, to make escape tunnel, construction of rescue tunnel from Barkot end, and ONGC to make vertical tunnel. After the auger joint of a drilling machine broke down, the rescuers drilled through the remaining few meters using the practice of rat-hole mining.

5. 05

   Total distance that debris covered: 57

   The rescuers dug through 57 metres of debris, of which 12 metres were dug through manually, for which at least six rat-hole miners were brought in.

6. 06

   Cost of entire tunnel project: Rs 853 crore

   The 4,531 metre-long Silkyara tunnel is part of the Chardham Project of the Ministry of Road Transport and Highways and is under construction by NHIDCL through M/s Navayuga Engineering Company Ltd at a cost of Rs 853.79 crore.