The Indian Army has joined the operation to rescue the 41 workers trapped inside the collapsed Silkyara tunnel in Uttarakhand, NDTV reported on Sunday.

A section of the under-construction tunnel on the Brahmakhal-Yamunotri national highway in Uttarkashi district collapsed in the early hours of November 12. The tunnel is part of the Char Dham Road Project to build all-weather roads in Uttarakhand.

The army soldiers will manually drill through the rubble to create an escape passage for the workers, NDTV reported.

Until now, an auger machine was being used for the drilling. The machine had drilled around 46 metres of debris and about 10 metres to 15 metres was remaining, officials had said earlier. However, the blades of the auger machine got stuck in the rubble on Friday.

The soldiers will manually drill through the remainder of the rubble.

The manual drilling will start after the parts of the auger machine are removed from the debris, Uttarakhand Chief Minister Pushkar Singh Dhami said.

Rescue teams have deployed plasma cutters flown in from Hyderabad to remove parts of the auger machine stuck inside the rescue passage, ANI reported.

Simultaneously, vertical drilling from the surface level into the tunnel started on Sunday.

On Sunday, the chief minister said that he met the family of one of the trapped workers and assured them that the government has been working with “full force” to get the workers out safely.

However, manual drilling means that the rescue operation may take longer than expected, officials said. “This operation could take a long time,” PTI quoted National Disaster Management Authority member Lieutenant General (Retired) Syed Ata Hasnain as saying.

Arnold Dix, the president of the International Tunnelling and Underground Space Association, reiterated that the workers would be evacuated “by Christmas”.

On Saturday, Dix, who is assisting the rescue operations, said that the teams have been looking at several options to bring back the trapped workers safely, but there would be no more drilling using the auger.

Also read: Uttarakhand tunnel collapse highlights the precarity of migrant workers