For 24 hours, Munna Qureshi kept digging away, metres deep inside a 2.6-feet-wide steel pipe. Hunched and weary, fatigue hit him in waves ever so often. But the 29-year-old from Delhi knew he couldn’t stop.

Behind him lay several yards of darkness, but before him lay the fate of 41 workers trapped in a tunnel for more than 400 hours. At that time, excavator machines and sophisticated drills had failed to bore through the debris. The job eventually fell to 12 so-called “rat-hole miners” or “rat miners” such as Qureshi, who were tasked with chipping away at 12 metres of debris — at the end of it lay freedom for all those men and relief for all their families.

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At 7.05pm on Tuesday, he pushed aside the last rock that stood between him and the survivors.

“I can’t describe my happiness,” Qureshi said, minutes after the first trapped worker was wheeled out around 7.45pm. “They hugged me, cheered in applause, and thanked me profusely.”

Feroz, another rat-hole miner, who helped dig through the last two metres of debris, left the tunnel in tears.

“I hugged one of the trapped workers and just wept,” he said.

A dozen men, largely from Uttar Pradesh and Madhya Pradesh and employed with a Delhi-based firm, were set into action on Monday evening, as a sort of last resort to manually carve through the debris, with the group emerging victorious on Tuesday evening, as 41 men were pulled out from the tunnel, in a heroic effort that underlines the endurance of human spirit.

But officials only turned to rat-hole mining, a primitive method of extracting coal deposits through narrow, horizontal passages, when more modern equipment collapsed in the face of the daunting challenge.

Since rescue efforts began late on November 12, authorities turned to a host of techniques to free the trapped workers. These included excavator machines, two types of auger machines (one of which was built in the US) and vertical boring machines. The first two failed after suffering irreparable damage owing to the largely unyielding debris, while the third faced hiccups hours after being put to use.

Instead, what worked finally was a technique that is illegal across India because of its associated dangers. Still, the method prevails in parts of Meghalaya, as well as on some construction sites, given the minimal capital costs involved and the availability of labour.

The term “rat-hole” refers to the narrow pits dug into the ground, typically just large enough for one person to descend and extract coal. The name comes from its resemblance to rats burrowing through narrow holes.

So, for the 12 rat miners who dug away at the debris left behind after the auger machine had to be discarded, the rescue was more than just that – it was also vindication.

Vipin Rajput, one of the 12, who lives in Jhansi in Uttar Pradesh, said he hopes people will now consider their work noble.

“I hope they will see us with some respect now because of the rescue,” he said.

Still, in the 24 hours till 7pm on Tuesday, doubt threatened to consume some of the trapped workers. After all, burly apparatus had failed, several times over.

“Often, we thought we may not succeed. But we did at last,” said Chandran, one of the 12 rat miners, struggling to control his emotions.

Explaining the operation, Munna Bhai, from Uttar Pradesh, said teams worked in shifts to clear the rubble that lay at the end of the pipe.

“Four teams worked in eight-hour shifts. At a given time, three workers were inside the pipe tunnel. Our job was to remove the debris as the pipe was being pushed through the debris,” he said.

People from Bundelkhand in Uttar Pradesh, where many of the 12 men hail from, said several of them earlier worked in granite and stone mines in the region. Many also worked in mines in Ahmedabad, Gujarat and Maharashtra.

Parsadi Lodhi, another rat miner also from Jhansi in Uttar Pradesh, said the operation was not difficult, but tiring.

“There was enough space inside to remove the debris,” said Lodhi, who has been doing this work for the past 10 years.

Qureshi said the day was a milestone in his life.

“I can’t express my happiness. I have done this for my fellow workers. I can never forget the respect they (the trapped workers) have given us.”