Rescuers drilled deeper into the rubble of a collapsed road tunnel in northern India on Friday to fix wide pipes for 40 workers trapped underground for a sixth day to crawl to their freedom.

Drilling with a new machine started on Thursday and has covered a stretch of 24 meters (78 feet) so far, Devendra Patwal, a disaster management official, said.

It may require up to 60 meters (195 feet) to enable the trapped workers’ escape, Patwal told The Associated Press on Friday.