The rescue of 41 construction workers who have been trapped in a collapsed tunnel in northern India for nearly two weeks ran into another delay during what was described as the final phase of digging to reach them, officials said Thursday.

The platform of the drilling machine got destabilized while piercing through rock debris, and technicians need to fix it before the rescue operation can resume, Kirti Panwar, a spokesperson for the Uttarakhand state government, said.

Officials earlier hoped to be ready to start bringing the workers out Thursday, but now that won't happen until Friday at the earliest.

"We are fixing the machine. It should be ready tomorrow," the Press Trust of India news agency quoted Arnold Dix, an international expert, as saying.

"Since the trapped workers on the other side of the rubble are safe and fit, not rushing has enormous value because if we rush in a situation like this, we might create problems we cannot imagine," Dix said.

The drilling also was interrupted on Wednesday night when boring machine hit a metal girder, causing some damage to its blades. That caused a six-hour delay as the rescuers cut the metal object and cleared the obstacle, officials said.

The machine started operating during the day Thursday, said Atul Karwal, chief of the state-run National Disaster Response Force.

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

Pushkar Singh Dhami, Uttarakhand state's top elected official, visited the site on Thursday and spoke to some of the workers in the tunnel by walkie-talkie, Karwal said.

As of Thursday evening, the drilling had made it through nearly 46 meters (151 feet) and needed to excavate up to 12 meters (40 feet) more to create a passageway, according to Kirti Panwar, a state government spokesperson at the accident site.

Rescue teams plan to insert and weld together pipes that would be the trapped workers' route to freedom. Approximately 46 meters of pipes have been put in so far, Panwar said.

Members of the National Disaster Response Force "will then crawl inside and bring out the workers one by one, most likely on stretchers which have been fitted with wheels," he said.

Rescuers resumed drilling horizontally through the entrance of the tunnel Wednesday after problems with the machine forced them to stop digging last week and consider alternate rescue plans.

The mountainous terrain in Uttarakhand has proved a challenge to the drilling machine, which broke down as rescuers attempted to dig horizontally toward the trapped workers. The machine's high-intensity vibrations also caused more debris to fall.

On Wednesday evening, ambulances and a team of 15 doctors were deployed to the accident site, PTI reported.

Relatives who had gathered there told PTI they were finally feeling optimistic after days of anxiety over the rescue and concern for their trapped loved ones.

Indrajeet Kumar said he felt hopeful and relieved after he was able to speak to his brother and another relative who were among the workers in the collapsed tunnel.

"They told me not to worry and that we would soon meet outside," he said, adding that both of them "were doing fine."

Authorities began supplying the trapped workers with hot meals, made of rice and lentils, through a 6-inch (15.24 cm) pipe earlier this week after days of them surviving off of dry food sent through a narrower pipe. Oxygen is being supplied to them through a separate pipe.

Officials on Tuesday released a video, after a camera was pushed through the pipe, showing the workers in their construction hats moving around the blocked tunnel while communicating with rescuers on the ground through walkie-talkies.

Uttarakhand is dotted with Hindu temples, and highway and building construction has been constant to accommodate the influx of pilgrims and tourists. The tunnel is part of the Chardham all-weather road, a flagship federal project connecting various Hindu pilgrimage sites.