New Delhi | The National Disaster Management Authority on Sunday said that work is on to retrieve broken parts of the auger machine and start manual digging while vertical drilling has also started to bring out 41 workers trapped in Silkyara tunnel in Uttarkashi for the last 14 days.

National Disaster Management Authority (NDMA) Member Lt Gen (retd) Syed Ata Hasnain told reporters here that all efforts are going on to rescue the workers.

Considered as the second best option, the work on vertical drilling started around noon and 15 meters of drilling has already been completed, Hasnain said.

After 86 meters of vertical drilling, the crust of the tunnel will have to be broken to bring out the trapped workers, he added.

The member also mentioned that as many as six plans are being executed to rescue the workers but the best option so far is horizontal drilling under which 47 meters of drilling have been completed.

Machines for undertaking sideways drilling (perpendicular drilling) are expected to reach the rescue site during night, Hasnain said.

Meanwhile, work is on to retrieve broken parts of the auger machine which encountered obstacles during the horizontal drilling, the NDMA member said, adding magna and plasma cutters are being used for the purpose.

Once the broken parts are retrieved, manual digging of 15 meters will be done to reach out to the trapped workers though it may take time, he said, stressing that all concerned agencies are working to make the rescue operation a success.

A plasma cutter was flown in from Hyderabad on Sunday to cut and remove parts of the auger machine stuck in the rubble inside the Silkyara tunnel.

A complete disengagement of the machine is necessary for the officials to resume the rescue work which involves manual pushing of pipes through rubble to prepare an escape passage. A part of a drill machine has also been sent atop the hill, above the tunnel, for vertical drilling.

A unit of Madras Sappers, an engineer group of the Corps of Engineers of the Indian Army, arrived at the site on Sunday to assist in the rescue operations.

Blades of the auger machine drilling through the rubble of the collapsed Silkyara tunnel to prepare an escape route got stuck in the debris on Friday night, forcing officials to consider switching to other options that could drag the rescue operation by several days, or even weeks.

On day 14 of the multi-agency rescue mission, officials shifted focus to two alternatives -- manual drilling through the remaining 10- or 12-metre stretch of the rubble or, more likely, drilling down 86 metres from above.

The rescue effort began November 12 when a portion of the under-construction tunnel on Uttarakhand's Char Dham route collapsed following a landslide, cutting off the exit for the workers inside.

The workers are in a built-up two-kilometre stretch of the tunnel. They are being sent food, medicines and other essentials through the six-inch wide pipe.