Three days after the auger machine broke down inside the steel pipe in the Silkyara tunnel, the rescue workers managed to remove all debris of the auger machine from the steel pipes. It has also been decided to start manual drilling of the tunnel to push in 800 mm steel pipes which would serve as an escape passage for the workers.
It was important to extract the shaft and fins of the machine from the rubble completely before starting the manual drilling.
Micro tunnelling expert Chris Cooper, who has been aiding the rescue team, told ANI that 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," added Cooper.
A plasma and laser cutter were brought from Hyderabad on Sunday to aid in clearing the debris of the 25-tonne machine.
Cooper said the pace of the operation will depend on how the ground behaves. "We have nine meters of hand tunnelling to do. Could be quickly, could be a bit longer. If we hit some lattice girder, then we've got to cut it out, but we're confident we can get through. The Army is just supervising (the operation)", he added.
Though vertical drilling is simultaneously being carried out, manual drilling is still considered the best option. Former Army Engineer-in-Chief, Lieutenant General Harpal Singh (Retd), told reporters that there is no other way left except the manual method to reach the trapped workers.
Singh was brought to the site to aid in the operations and to provide technical inputs. "Efforts are underway to remove the 1.5 meters of the damaged pipe. After its removal, strengthening and muck clearance, skilled labourers will go in with the help of the army. We hope this will be done so," he told reporters.
Meanwhile, manual drilling will also see the rescuers use the rat hole mining technique 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 six specialists have reached the site to undertake the manual drilling work. A team of 11 people will go inside the 800 mm pipe of the tunnel to remove the debris manually, reported ANI. The team includes engineers from the Indian Army's Madras Engineering Group as well as civilians.