In an effort to step up the rescue operations in Uttarkashi, a rat hole mining technique will be used for manual drilling to remove the debris inside the pipe on the 16th day of continued rescue efforts in the Silkyara tunnel, according to officials.
As per the official sources, a team of 6 specialists have reached the site to undertake the manual drilling work. They 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.
Apart from the drilling machine, a hammer, a shovel, a trowel, and a life support device for oxygen will be carried by these specialised teams while going inside the tunnel.
The auger machine being used for horizontal drilling of the tunnel that got stuck inside the pipe was cut and removed earlier today using a plasma cutter. The auger machine stuck inside the pipe, produced 48 m of debris on the mouth of the tunnel, which will also be removed by the rat miners.
Rat miners are specialists in digging and drilling manually in narrow passages including tube mines who mostly work in mines and have the experience of drilling for hours.
The rat hole mining technique is generally used in coal mining, especially in regions that have difficult terrain.
“It is a challenging operation. We were called in from Delhi. We reached here yesterday. We are basically from Madhya Pradesh. We will try our best to complete the drilling process as soon as possible,” one of the civilian specialists who reached the site to carry out manual drilling told ANI.
The Army’s engineering unit has made steel frames of 1.2×1.5 m whose thickness is 1 m. The Madras Sappers along with the help of other agencies will take the frames one by one from the mouth of the tunnel to the inside which will also take at least 10 days.
Thirty personnel of the engineer regiment are at the spot to expedite the rescue operations.
Over 35 metres of vertical drilling work have been completed so far out of the 86 metres needed to reach the trapped workers.
SJVN, a public sector undertaking company involved in hydroelectric power generation and transmission, started the vertical drilling work on the top of the tunnel atop the hill on Sunday, November 26.
This machine has the capacity to go only to a depth of 45 meters, after which the machine and its parts will be replaced and then the manual drilling work will start.
Today is the second day of vertical drilling and as per National Highways and Infrastructure Development Corporation Limited (NHIDCL), the drilling work is expected to be completed by November 30, as the agencies have set a time frame of 100 hours i.e. four days for it.
A delegation led by Principal Secretary to Prime Minister, Pramod Kumar Mishra took stock of ongoing efforts to rescue 41 trapped workers in the Silkyara tunnel in Uttarkashi on the 16th day of the operations.
Union Home Secretary Ajay Kumar Bhalla and Uttarakhand Chief Secretary SS Sandhu along with Pramod Kumar Mishra inspected the work inside the tunnel.
Micro tunnelling expert Chris Cooper said earlier on Monday (27th November) that all the debris from the auger machine has been removed and manual drilling to reach the trapped labourers will start in a few hours.
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, on Monday morning.
Vouching for the manual method, former Army Engineer-in-Chief, Lieutenant General Harpal Singh (Retd), told ANI that there is no other way left except the manual method to reach the trapped workers.
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.
(This news report is published from a syndicated feed. Except for the headline, the content has not been written or edited by OpIndia staff)
