Rescue workers have broken through to the 41 workers trapped in a collapsed tunnel in Uttarkashi, Uttarakhand.

Footage from November 28 shows rat hole miners at work digging a narrow tunnel big enough for just a single person to fit in.

The workers, who have been trapped since November 12, will be extracted one by one through a 90cm diameter pipe.

A team of "rat-hole miners" began manual drilling operations yesterday to reach the 41 workers trapped within the debris of the collapsed Silkyara tunnel in Uttarakhand's Uttarkashi as rescue ops entered Day 17. A team of 24 seasoned "rat-hole mining" experts are involved in the manual drilling process and excavate a narrow passageway toward the trapped workers. This time-consuming task will involve removing debris and creating a safe route for the rescue operation. The workers are just 5 metres away from the rescue team.

Uttrakhand Chief Minister Pushkar Singh Dhami says, "Almost 52 metres has been done (pipe inserted). It is expected that there will be a breakthrough around 57 metres. 1 metre of the piple was pushed in before me, if 2 metres more of it is pushed in it will be around 54 metres in. After that, one more pipe will be used in...Earlier steel girders were found (during drilling), this has reduced now. Right now, we are finding more of concrete, it is being cut with cutter."

Manual drilling operations began at the tunnel yesterday. Initial drilling efforts were conducted using a large auger machine that got stuck in the rubble on Friday, prompting authorities to look for alternative methods - vertical drilling from above the tunnel. Approximately 40% of the required 86-metre vertical drilling has been completed.

The last bit of the stuck auger was removed by Monday evening allowing for the insertion of a steel pipe deeper into the partially constructed escape passage. The 25-tonne machine, once repaired, will push an 800-mm pipe forward as the manual drilling progresses.