As operations entered the 13th day to rescue labourers trapped in the Uttarakhand tunnel, work on horizontal drilling to create an access passage from the Silkyara end—considered the most promising lead—has stopped as the Augur machine got damaged leading to minimal progress in the last 24 hours. 

Currently, efforts are on to remove the damaged portion (rotor) of the Augur drilling machine from the access tunnel, post which manual drilling will be done to cover the remaining around 12-15 meters. So far, the passage has reached 47 meters. The passage will be cleared and manual drilling is expected to start from Sunday (November 26).

National Highways & Infrastructure Development Corporation (NHIDCL) is conducting this horizontal drilling from the Silkyara end, which is the most promising lead to reach the labourers who have been trapped in the collapsed tunnel since November 12.

Horizontal drilling

Briefing the media on Saturday at 1600 hrs, National Disaster Management Authority (NDMA) Member, Lt General Syed Ata Hasnain (Retd) said “Augur drilling has stopped as its front portion got damaged and is stuck. It is being removed. We need to have some patience as this is a very difficult operation. Currently, the situation is that 47-meter digging has been done, we have to keep it stable and remove the broken part of the Auger machine. It (rescue) will take time as utmost care is needed”

Two methods are being used currently, but a third method that is in the draft may also be used soon, he indicated, adding that the rescue operation could be prolonged and there is a need to boost the morale of the labourers and the family members.

Hasnain assured that the work to remove the damaged portion of the Augur is in progress and special cutters are being brought in by the Indian Air Force. The special cutters are expected to arrive at the rescue site on Saturday.

When asked about the time it will take to manually drill the remaining 10-15 meters, officials said that a clear timeline is difficult as it is not clear how much debris would be encountered. It could take one hour to dig a meter (with debris and clearing it from the passage) or an hour to clear 2-3 meters (under ideal conditions).

Vertical drilling

Vertical drilling from the top of the tunnel from the Silkyara end is the other best option to reach the trapped labourers. Machinery has reached the spot and is being installed. The dimension of this tunnel will be 1.2 meters. Around 86 meter depth is to be covered for creating this vertical passage from the top of the tunnel. It could take up to 48 hours for this exercise to begin. Hydropower enerator SJVNL will be doing the vertical drilling.

“The platform for launching the drilling machine has been completed. Marking of drilling points over the tunnel has been finalised after discussion with the Geological Survey of India (GSI), Rail Vikas Nigam (RVNL), and Oil &Natural Gas Corporation (ONGC). The assembly of the machine has started,” the Ministry of Road Transport & Highways (MoRTH) said in its update for November 25th till 1500 hrs.

Meanwhile, speaking to reporters at the rescue site on Saturday, micro tunnelling expert Arnold Dix said that the labourers will be going home by Christmas.