Uttarkashi, Nov 24 (PTI) Drilling through the rubble to prepare an escape route for the 41 workers trapped inside the Silkyara tunnel was set to resume on Friday morning, a day after another snag hit the rescue efforts, an official said.

Former advisor to the prime minister's office Bhaskar Khulbe said the operation might successfully be completed by Friday evening if everything went well.

Citing the data scanned by a ground penetrating radar, there is no metallic obstruction up to five metres beyond the 46 metre point through the rubble.

The drilling machine's platform has been revamped and strengthened. Boring through the rubble with auger is likely to resume by 11.30 am, Khulbe told reporters at Silkyara.

'We have 12-14 metres more to go. And I hope if all goes well we might conclude the operation by Friday evening,' he said. PTI COR ALM NB NB