Whatever is required to save the 41 trapped workers will be done and keeping the morale of workers and their family members high should be everyone's collective responsibility, Union minister Nitin Gadkari said on Sunday as he reviewed the rescue operation at the partially collapsed Silkyara tunnel.

The minister for road transport and highways, who was accompanied by Uttarakhand Chief Minister Pushkar Singh Dhami, said the rescue operation is challenging as the soil strata in the Himalayan region is not uniform.

It is soft at some places and hard at other places which makes any mechanical operation difficult, he said.

Horizontal drilling with the American auger is the quickest method in the given circumstances to reach the trapped workers, Gadkari said.

"American auger was working alright when it was drilling through soft soil. It faced some problems after it encountered some hard obstacle that led to the machine applying greater pressure and creating vibrations following which it was stopped for safety reasons," he said at a press conference in Silkyara.

"We are working on six options simultaneously. The PMO is also closely monitoring the operation. Our biggest priority is to save all those who are trapped and as soon as possible. Whatever is needed will be done," he said.

Whichever machine or technical assistance is required will be provided, he said.

"Keeping up the morale of the trapped workers and their family members should be everyone's collective responsibility at the moment," he said.

He said the trapped workers are being constantly provided oxygen, electricity, food, water and medicines.

Apart from one pipeline through which they were supplied food earlier, an alternative larger-diametre pipeline has also been inserted up to 42 metres through the rubble so that food like roti, vegetables and rice apart from light food could also be supplied to them, he said, Road, Transport and Highways Secretary Anurag Jain also said that multivitamins, antidepressants and dry fruits are being provided to the 41 workers trapped for the past seven days.

"Fortunately, there is light inside because the electricity is on. There is a pipeline, and thus water is available. There is a 4-inch pipe, which was used for compression. Through that, we are sending food from day 1," he said.

Jain, in a video brief update on the rescue operation, further said there is water and electricity in two km portion inside the tunnel, which is the finished part of the 4.531-kilometre two lane bi-directional tunnel at Silkyara in Uttarkashi.

Experts from different fields have been pooled in and asked to suggest whatever methods can be applied to ensure the safe and early evacuation of the trapped workers, Gadkari said.

Preparations are on to start vertical drilling through the hill above the tunnel, he said, adding every possible method is being tried for their speedy evacuation.

Gadkari said tunnels at a cost of approximately Rs 2.75 lakh crore are being built by the Centre in Jammu and Kashmir, Himachal Pradesh and Uttarakhand.

Except for the headline, this story has not been edited by The Telegraph Online staff and has been published from a syndicated feed.