Uttarkashi (Uttarakhand) [India]: As operations to rescue the 41 trapped workers at the Silkyara Tunnel collapse site entered day 16, there was some positive news with Micro tunnelling expert Chris Cooper saying that all the debris of the auger machine has been removed and manual drilling to reach the trapped labourers will start in a few hours.
“All the debris (of the Auger machine) removed. (Manual drilling) will probably start after 3 hours,” Chris Cooper told media today.
Earlier today, the auger machine being used for horizontal drilling of the tunnel that got stuck inside the pipe was cut and removed using a plasma cutter.
“We have 9 meters of hand tunnelling to do. It really depends on how the ground behaves. Could be quickly, could be a bit longer. If we hit some lattice girder. Then we’ve got to cut out the lattice girder, but we’re confident we can get through. The Army is just supervising (the operation). 30 metres of (vertical drilling) has been done”, he added.
Vouching for the manual method, former Army Engineer-in-Chief, Lieutenant General Harpal Singh (Retd), earlier today, said that there is no other way left except the manual method to reach the trapped workers.
Singh said that he reached the site to provide technical inputs and further aid the ongoing rescue operations. He added that efforts are made on all fronts to speed up the rescue process.
As per official sources, the rat hole mining technique will be used through manual drilling to remove the debris inside the pipe to accelerate the rescue.
The rat hole mining technique is generally used in coal mining, especially in regions that have difficult terrain.
A team of 6 specialists have reached the site to undertake the manual drilling work and a team of 11 people will go inside the 800 mm pipe of the tunnel to remove the debris manually. The team includes engineers from the Indian Army’s Madras Engineering Group as well as civilians.
In collaboration with the Border Road Organisation and other agencies, efforts are also underway to enter from the other mouth of the tunnel that is the Barkot side. Four blasts were undertaken under the supervision of BRO and so far only 10 metres out of 500 meters have been covered.
Also, the rescuers are planning to build a mini tunnel along the left side of the tunnel, horizontal but perpendicular to the Silkyara tunnel, the work of which will be undertaken by SJVN.
After a portion of the tunnel caved in on November 12, the debris falling in the 60-metre stretch on the Silkyara side of the tunnel trapped 41 labourers inside the under-construction structure.
