Rescuers in India began digging manually Monday in hopes of reaching 41 construction workers who have been trapped in a collapsed mountain tunnel in the countrys north for over two weeks.

Kirti Panwar, a state government spokesperson, said a dozen men were taking turns burrowing into the debris with hand-held drilling tools for what was hoped would be the final stretch. They had dug nearly one metre (3.2 feet) and had up to 11 more metres (36 feet) to go, he said.

Rescuers have also started to create a vertical channel with a newly replaced drilling machine, officials said. They drilled horizontally for a week but the mountainous terrain proved too much for the machine, which broke down repeatedly before it was damaged irreparably on Friday, officials said.

The work being done now is designed to create a passageway for evacuating the trapped workers. Rescue teams have inserted pipes into dug-out areas and welded them together so the men can be brought out on wheeled stretchers.

Rescuers worked overnight to pull out parts of the broken drilling machine stuck inside the pipes so manual digging could start, Devendra Patwal, a disaster management official at the site, said.

The workers have been trapped since Nov. 12 when a landslide in Uttarakhand state caused a portion of the 4.5-kilometre (2.8-mile) tunnel they were building to collapse about 200 metres (650 feet) from the entrance.

What began as a rescue mission expected to take a few days has turned into weeks, and officials have been hesitant to give a timeline for when it might be completed.

The vertical digging, which started Sunday, required the rescue team to excavate about 106 metres (347 feet) of dirt and debris. The length is nearly double the approximately 60 metres (196 feet) they needed to dig through horizontally from the front.

They could also face similar risks or problems they encountered earlier that damaged the first drilling machine attempting to cut through rocks. The high-intensity vibrations from drilling could also cause more debris to fall.

Patwal said they were prepared for all kinds of challenges, but hoped they wouldnt face stiff resistance from the mountain.

We dont know what the drilling machine will have to cut through. It could be loose soil or rocks. But we are prepared, he said.

As the rescue operation entered its 16th day, uncertainty over its fate has been growing. Some locals offered Hindu prayers near the tunnel.

Some officials were hopeful that the rescue mission would be completed last week. Arnold Dix, an international expert assisting the rescue team, however, told reporters he was confident the workers would be back with their families by Christmas, suggesting they were prepared for a longer operation.

Most of the trapped workers are migrant labourers from across the country. Many of their families have travelled to the location, where they have camped out for days to get updates on the rescue effort and in hopes of seeing their relatives soon.

Authorities have supplied the trapped workers with hot meals through a six-inch (15-centimetre) pipe after days of surviving only on dry food sent through a narrower pipe. They are getting oxygen through a separate pipe, and more than a dozen doctors, including psychiatrists, have been at the site monitoring their health.

The tunnel the workers were building was designed as part of the Chardham all-weather road, which will connect various Hindu pilgrimage sites. Some experts say the project, a flagship initiative of the federal government, will exacerbate fragile conditions in the upper Himalayas, where several towns are built atop landslide debris.

Large numbers of pilgrims and tourists visit Uttarakhands many Hindu temples, with the number increasing over the years because of the continued construction of buildings and roadways.