The Centre and State government are working on half a dozen action plans, including horizontal and vertical drilling to create a passage, to save labourers trapped inside the Silkyara tunnel in Uttarkashi district of Uttarakhand.
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.
“The labourers are safe in the 2 km constructed section of the tunnel. There is electricity and water. Food and medicines are being delivered through the dedicated 4-inch compressor pipeline,” Road Secretary Anurag Jain said at a media briefing.
Jain explained that the government is working on 5-6 action plans, which includes horizontal drilling using an augur drill.
In the meantime, National Highways and Infrastructure Development Corporation (NHIDCL) on Sunday managed to lay another lifeline service by pushing a 150 mm diameter (6 inch) steel pipe through the debris by ROC machine.
The pipe has been successfully inserted in the entire length of around 57 meters. Some fruits items were also supplied to the trapped labourers. Video connection was established with the stranded workforce. Some debris was found inside the pipe and cleaning of the pipe using compressed air and water pressure was done at night. Further cleaning has been completed using compressed air.
Two vertical drilling exercises are under way from the Barkot and Silkyara end by Oil and Natural Gas Commission (ONGC) and Rail Vikas Nigam (RVNL), respectively.
On the Barkot end, the ONGC drilling team completed the inspection on Sunday and the report is to be submitted by Monday. Post this, the Border Roads Organisation (BRO) will conduct road alignment for movement of personnel and equipment.
On the Silkyara end, from where RVNL is drilling, the BRO has completed the access road. RVNL had requested for electric connection, which has been provided. The vertical drilling will be completed by November 26.
Another action plan is with RVNL creating a 170 metre tunnel for which the requisite equipment has reached Dehradun from Nashik and is now in transit. The equipment will be set up by November 23.
Hydro power generator THDC India, as part of the third action plan, has started drifting work at the Barkot end to construct a 483 meter tunnel. Two blasts were taken with the first resulting in a total 6.4 metre drift which was followed by wire mess laying. Further work has also started.
NHIDCL has resumed horizontal boring from the Silkyara end to rescue workers using an augur boring machine. The fabrication of a protective canopy for the drilling machine is underway, with modifications to the augur diameter and welding of pipeline is in progress.
Besides, hydro power generator SJVN will drill a 1.2 metre bore hole from the Silkyara end. On this, the BRO completed the access road and handed over the site to SJVNL. The drilling machine is in transit. The work is expected to start on Monday by 8 pm.
A drift tunnel is also being created by manual-semi mechanised method by a joint team of THDCL, Army, Coal India and NHIDCL. The work is underway to create a drift inside the tunnel with a safe channel established from 180 metres to 150 metres . The Army is mobilising box culverts for this purpose.