Just a few metres of rock and earth separate Indian rescue teams from 41 workers who have been trapped inside a collapsed road tunnel for nearly two weeks, officials said Friday, vowing to get all the men out safely.
After a series of rapid advances, hopes that the men's freedom was imminent were dashed late Wednesday when the drilling machine powering through tonnes of rock and concrete ran into metal rods, but those have now been cleared.
An AFP reporter could see sparks flying as workers in the entrance of the tunnel welded together the final sections of steel pipe, to make the tube that will provide a safe exit for the trapped workers.
Rescue teams have stretchers fitted with wheels ready to pull the exhausted men through 57 metres (187 feet) of pipe once it has been driven through the final section of rubble blocking their escape.
"We have to (drill) 14 metres further inside the tunnel," Bhaskar Khulbe, a senior government official overseeing rescue efforts, told reporters on Friday, adding that the "trapped workers are in good frame of mind".
Officials have repeatedly predicted they were within a few hours of a breakthrough, but a government statement has also noted that any timeline is "subject to change due to technical glitches, the challenging Himalayan terrain, and unforeseen emergencies".
Ambulances are on standby and a field hospital has been prepared to receive the men, who have been trapped since a portion of the under-construction Silkyara tunnel in the Himalayan state of Uttarakhand caved in 13 days ago.
'Get these brave men out'
Syed Ata Hasnain, a senior rescue official and retired general, said their efforts were "like battle".
"By any means, we must get these brave men out", he told reporters on Friday afternoon, adding that "all resources" needed were being utilised.
"This is a war that is being fought to save the sons of India who have been toiling up there in the mountains," Hasnain said, adding that the final stretch was critical.
"We are going to be very, very careful in further progress", he said.
The area outside the tunnel has been a flurry of activity, with worried relatives gathering and rescue teams stopping to pray at a Hindu shrine erected at the entrance.
National Disaster Response Force chief Atul Karwal said his teams had been rehearsing how -- once the steel pipe breaks through -- they would bring the men out as quickly and safely as possible.
"The boys will go in first," he said Thursday. "We have put wheels under the stretchers so that when we go in, we can get the people out one by one on the stretcher -- we are prepared in every way."
Rescue efforts have been hit with repeated delays caused by falling debris, fears of further cave-ins and drilling machine breakdowns.
Arnold Dix, president of the International Tunnelling and Underground Space Association, who is at the site assisting the rescue, said engineers had even faced having to cut through construction vehicles buried in the earth when the roof first collapsed.
Uttarakhand chief minister Pushkar Singh Dhami said work was on a "war footing".
"We are trying to overcome all the obstacles soon, and bring all the workers out safely," Dhami said Friday.