New Delhi/IBNS: Five days after an under-construction tunnel collapsed in Uttarakhand trapping 40 labourers, a special machine has been flown to the spot to expedite the rescue work, media reports said.

In an interview with NDTV, National Disaster Relief Force (NDRF) Atul Karwal said that they are "hopeful" that the labourers could be brought to safety within "12 to 15 hours".

According to reports, the special machine-an American Auger drill-is expected to cut through 70 meters of rock, much of which came down from the roof during the rescue efforts in approximately 12 to 15 hours.

The machine works at a "theoretical speed" of 5 meters an hour.

The authorities are planning to bore through the rock and insert an 80 mm (less than 3 feet) through which the labourers can crawl through.  In case anyone is incapacitated or injured, "we can use stretchers and harnesses to bring them out," Karwal told NDTV.

The rescue work that started on Sunday after a section of the tunnel roof collapsed, suffered several setbacks due to rock fall.

The last few have increased the length of the blocked portion from an initial 40 to 50 meters to an approximate length of 70 meters. 

Elite rescue teams from Norway and Thailand and the one that successfully rescued the trapped children from a cave in Thailand in 2018 have joined forces to evacuate the 40 workers trapped in an under-construction tunnel in Silkyara in Uttarakhand's Uttarkashi district, media reported.

A section of the tunnel, a unit of the ambitious Char Dham all-weather road project, collapsed on Sunday due to a landslide. The collapsed portion, measuring 30 meters, is located 270 meters from the tunnel's entrance on the Silkyara side.

The rescue operations entered the fifth day on Thursday. The approximately 50 metres of debris is posing a big challenge for the rescuers in the fragile mountains where the tunnel is located. The debris needs to be penetrated to insert 800 mm and 900 mm of evacuation tubes.

If this can be achieved, the trapped workers on the other side of the collapsed tunnel can crawl out safely.