Drilling to create a vertical escape route for the 41 workers trapped inside the collapsed tunnel in Silkyara here for two weeks began on Sunday, an official said, a day after an auger machine carrying out horizontal drilling broke down.

"Vertical drilling has begun and (a stretch of) up to 15 metres has been drilled already," NHIDCL MD Mahmood Ahmed told reporters in Silkyara.

If it does not face any hurdle, it will take nearly 100 hours to reach the trapped workers from the top of the hill above the tunnel.

Officials had earlier said rescuers have to drill down 86 metres from above.

The vertical drilling began a day the auger machine's blades got stuck inside the rubble, hindering the multi-agency rescue effort that began on November 12 when a portion of the under-construction tunnel on Uttarakhand's Char Dham route collapsed following a landslide, trapping the 41 workers inside.

The removal of the shaft and fins of the auger machine stuck in the debris is underway with plasma and laser cutters inside the tunnel, state nodal officer for the rescue operations Neeraj Khairwal said.

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