Explained | Uttarkashi tunnel collapse: All 41 workers rescued. Here's a timeline of what happened

Forty-one construction workers who were trapped inside a collapsed tunnel for 16 days in the Indian State of Uttarakhand were finally rescued on Tuesday (Nov 28). The construction workers had been trapped since Nov 12 after the under-construction tunnel collapsed following a landslide. It was sixteen days of day and night efforts by government agencies to rescue them.

Uttarakhand Chief Minister Pushkar Singh Dhami expressed joy over the workers being rescued from the tunnel site. "We have begun bringing the workers out...," he said in a post on X when eight of the workers were brought out of the tunnel.

Click here to follow all updates on Uttarkashi tunnel rescue operation

Sharing a post on X, Prime Minister Narendra Modi said that the courage and patience of the trapped workers inspired everyone. "I also salute the spirit of all the people associated with this rescue operation," Prime Minister Modi added.

Here's a look at the timeline so far:

> Nov 12: Forty-one workers were trapped inside the Silkyara tunnel in Uttarkashi after a portion of the under-construction tunnel collapsed following a landslide. The rescue operation started immediately and authorities said that all the trapped construction workers were safe and basic supplies like oxygen, food, and water were being given to them.

> Nov 13: Uttarakhand Chief Minister Pushkar Singh Dhami visited the incident spot and took stock of the situation. Excavators had been removing debris to carve out a path to reach the workers. "There is enough water while oxygen and food for instant energy like dry fruits are being supplied to them," a disaster management official told Reuters.

> Nov 14: Excavators started drilling with the help of auger machinery to fix a wide steel pipe that would help pull out the trapped workers. A team of geologists from the state government and educational institutions had arrived to determine the cause of the accident. Families of the trapped workers urge swift rescue operation.

> Nov 15: Falling debris hampers rescue efforts. Workers remained safe with food, water, and oxygen being supplied through a pipe. Dozen workers outside the Silkyara tunnel called for their colleagues to be rescued quickly.

> Nov 16: A new drilling machine was installed after the National Highways & Infrastructure Development Corporation Limited (NHIDCL) was dissatisfied with the first one. Ranjit Sinha, the top disaster management officer in Uttarakhand, told Reuters the new machine would cut through the debris at 2.5 metres an hour, as opposed to one metre using the previous machine.

> Nov 17: Rescuers drill through 24 metres of debris. Four millimetre (mm) pipes are inserted into the tunnel. However, the rescue efforts are hampered when one of the pipes hits an obstacle. A report from the NHIDCL said that during efforts to restart the drilling machine, a "large-scale cracking sound" was heard which created a situation of panic in the tunnel.

> Nov 18: Drilling remains suspended. The workers remained safe and were able to establish communication via radios. Protesting workers alleged rescue teams were keeping them in the dark about the pace of progress of the rescue.

> Nov 19: Drilling remains suspended. Union Transport Minister Nitin Gadkari reviewed the rescue operation and said that boring horizontally with the huge auger machine appeared to be the best option.

> Nov 20: Prime Minister Narendra Modi held a telephone conversation with Chief Minister Dhami to review the progress of the rescue operation. Experts surveyed the collapse site to gather information about the tunnel collapse from every angle and later discussed possible routes of rescue for the trapped workers. Rescuers pushed through a new pipeline to the trapped workers. They had been relying on nuts, puffed rice, chickpeas and other dry food via a smaller pipe. 

> Nov 21: Authorities released the first video of the 41 workers trapped inside the tunnel after a camera was sent into the tunnel through a new pipeline. Two explosions were carried out at the Balakot end of the tunnel. Workers were told to practise yoga and meditation for anxiety. 

> Nov 22: Rescue teams drilled 32 metres of an estimated 60 metres that must be cleared to push through a pipe wide enough for the workers to crawl out. However, drilling was hampered after some iron rods came in the way of the auger machine.

> Nov 23: Drilling resumed and ambulances and medical support were kept on standby. Rescue operation entered the final stages. 

> Nov 24: Rescue efforts were again hampered after the auger machine faced a hurdle, soon after the drilling resumed.

> Nov 25: A rescue official told Reuters that the operation would be further slowed as rescue teams were considering drilling through the last 10 metres of debris manually. A family member of the trapped worker said that everyone (trapped workers) inside the tunnel was very worried.

> Nov 26: Rescuers started drilling vertically from the top of the mountain where the workers were trapped. A National Disaster Management Authority (NDMA) official said, "86 metres will have to be reached through vertical drilling to reach trapped workers."

> Nov 27: Rescuers brought in rat miners to drill through a narrow pipe by hand and help pull out the trapped workers. The NDMA said that there would be rain the area in the area in the next day or two but added it would not affect the operation.

> Nov 28: All 41 workers were rescued and were taken to hospital for treatment. Rescuers drilled through rocks and debris to finally reach the workers.

(With inputs from agencies)