New Delhi | Manual horizontal digging will start soon in addition to the ongoing top-down drilling to rescue the 41 trapped workers in the Silkyara tunnel in Uttarkashi, NDMA said on Monday.

Manual drilling was resorted to as the auger drill -- a corkscrew-like device with a rotary blade at the front end -- which drilled up to 46.8 metres busted as it hit several hurdles on the way and got entangled in a girder in the debris.

Vertical and manual horizontal drilling are the two methods on which rescue efforts are being focused at the moment. Work on the other options, such as horizontal drilling from the Barkot end of the tunnel is also underway.

A total of 86 metres have to be drilled vertically to prepare an escape passage. Pipes of 1.2 metres in diameter have to be laid vertically through the top of the tunnel on which work began on Sunday as a second option to reach the stranded labourers.

Giving an update on the rescue operations, National Disaster Management Authority (NDMA) Member Lt Gen (retd) Syed Ata Hasnain told reporters here that rat-hole miners will start manual digging shortly. Broken parts of the auger machine have been removed from the rubble with the help of a plasma cutter flown in from Hyderabad.

He further said the government is fully committed to the safe rescue of all the 41 workers who have been trapped in the tunnel since November 12.

Hasnain said both private and public agencies are involved in the rescue operations.

Prime Minister's Principal Secretary PK Mishra, Home Secretary Ajay K Bhalla and Uttarakhand Chief Secretary S S Sandhu also took stock of the ongoing rescue operations.