The Ministry of Road Transport and Highways (MoRTH) said on Wednesday that rescue operations have intensified with around 67 per cent augur drilling (horizontal) completed at the tunnel collapse site at Silkyara in Uttarakhand.
The National Highways and Infrastructure Development Corporation (NHIDCL) has resumed horizontal boring from the Silkyara end to rescue workers using an Augur boring machine. As on date, pipes measuring 42 metres have been inserted. The fabrication of a protective canopy for the drilling machine is underway, MoRTH said.
Another positive development is that the second 6-inch lifeline (pipeline) has become operational through which the trapped 41 labourers were provided with food and medicines supplies.
Besides, a modified communication system with wire connectivity has also been developed by National Disaster Response Force (NDRF)/ State Disaster Response Force (SDRF) through which clear communication is made and the people inside reported in the morning that they were safe.
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On November 12, a collapse occurred at the under-construction tunnel from Silkyara to Barkot, which led to 41 labourers getting trapped in the under construction tunnel.
Considering the various rescue operations being conducted and the situation on the ground, experts said that it would take anywhere between 3-15 days for the trapped labourers to be rescued from the collapsed tunnel.
The labourers are trapped in a 2 km section of the tunnel, which has completed concrete work thus ensuring the workers safety. This portion is the focus of the rescue efforts. Here, electricity and water supply is operational.
Hydro power generator SJVNL’s machine for the vertical rescue tunnel construction has arrived at the site and has been installed. Furthermore, THDC India has initiated the construction of a rescue tunnel from the Barkot end, with four blasts already completed, resulting in a 9.10 meter drift. Now, efforts are being made to carry out three blasts per day.
Some progress has also been made in the perpendicular horizontal drilling by Rail Vikas Nigam (RVNL). Here, equipment for micro tunnelling required for horizontal drilling to rescue labourers has reached the site and additional back up machines are in transit.
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Oil and Natural Gas Corporation (ONGC) is mobilising machinery from the US, Mumbai, and Ghaziabad for vertical boring.
For creating a drift tunnel by manual semi-mechanised method by a joint team of THDCL, Army, Coal India and NHIDCL, work is underway to create a drift inside the tunnel, with a safe channel established from 180 metres to 150 metres. The Army is now mobilising box culverts. Fabrication of 8 frames has been completed.
The Border Roads Organisation (BRO) has completed construction of an approach road for vertical drilling by SJVNL and RVNL. BRO is also building an approach road for ONGC with geological surveys conducted by ONGC.