Silkyara/IBNS: The mammoth rescue operation to evacuate the 41 trapped workers in a tunnel in Uttarakhand's Silkyara came to an end Tuesday after a 17-day multi-agency drill. All 41 labourers were brought out of the tunnel bringing a sigh of relief nationwide.

After several high-tech machines failed, the rescuers relied on the banned manual "rat-hole"-mining technique to drill through the nearly 60 metres of rock that threatened to bury the workers.

Three teams of the National Disaster Response Force, or NDRF, went inside the tunnel to bring out the trapped workers.

The India Air Force (IAF) kept its Chinook helicopter on standby at Chinyalisaur airstrip in Uttarakhand, about 30 km away from the Silkyara tunnel, to airlift workers after their rescue from the tunnel.

The chopper can be used if any rescued workers need urgent medical attention.

The labourers, in such cases, can be airlifted either from the tunnel site to the Chinyalisaur hospital (a distance of 30 km) or flown to the premier All India Institute of Medical Sciences in Rishikesh (a distance of around 160 km).

The first three workers to be rescued were brought out on specially modified stretchers; these were lowered manually down a two-metre-wide pipe inserted into holes drilled into the hillside.

An emergency medical centre has been set up in Chinyalisaur to treat the 41 workers trapped underground in the Silkyara tunnel since Nov 12.

Forty-one ambulances are on standby at the site of the tunnel collapse, one for each worker, to bring them to the Chinyalisaur hospital by road.

Local police will organise a 'green corridor' to ensure each ambulance reaches the hospital as quickly as possible.

A makeshift medical centre has also been set up - at the mouth of the collapsed tunnel - to provide first aid and emergency care.