NEW DELHI (AP) — Attempts to reach 41 construction workers stuck in a collapsed tunnel in northern India for two weeks were again stymied Saturday.

The drilling machine broke down late Friday while making its way through the rubble, stones and metal, forcing the rescuers to work by hand to remove debris in hopes of reaching the stranded workers, but the whole operation has currently ground to a halt.

Arnold Dix, an international expert assisting the rescue team at the accident site in the mountainous Uttarakhand state, said it is unclear when the drilling will start again.

“The machine is busted. It is irreparable,” he told reporters. “The mountain has once again resisted the auger (machine).”

Dix said the rescuers would need to pull out the entire drilling machine and replace it to restart the digging. He didn’t specify how much time it would take.

The workers have been trapped since November 12 when a landslide 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. The mountainous terrain in the area has proven to be a challenge for the drilling machine, which had earlier broken twice as rescue teams attempted to dig horizontally toward the trapped workers.

The machine stopped working after it had drilled about two metres (6.5 feet) of the last stretch of 12 metres (40 feet) of rock debris that would open a passage for the workers to come out from the tunnel.

Rescuers have inserted pipes into the dug-out channel and welded them together to serve as a passageway from where the men would be pulled out on wheeled stretchers. About 46 metres (151 feet) of pipe has been put in so far, according to Devendra Patwal, a disaster management officer.

Meanwhile, a new drilling machine used to dig vertically was brought to the accident site Saturday.

The vertical dig is seen as an alternative plan to reach the trapped men, and rescuers have already created an access road to the top of the hill. However, rescue teams will need to dig 103 metres (338 feet) downward to reach the trapped workers — nearly double the distance of the horizontal shaft.

Authorities have supplied the trapped workers with hot meals made of rice and lentils through a six-inch (15-centimetre) pipe after days when they survived on dry food sent through a narrower pipe. Oxygen is being supplied through a separate pipe, and more than a dozen doctors, including psychiatrists, have been at the accident site monitoring their health.

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

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 Uttarakhand’s many Hindu temples, with the number increasing over the years due to the continued construction of buildings and roadways.