Amid the ongoing Uttarakhand tunnel rescue, the rescue teams have started manual drilling and excavation horizontally using the rat-hole mining method.

The mission is conducted to evacuate the 41 workers trapped inside for 16 days, people familiar with the matter said, adding that six rat-hole mining experts have been deployed for the rescue operation.

Officials involved in the rescue operation said that the horizontal drilling through the last 10-12 metres of debris of the collapsed portion of the tunnel will be done manually by a team of six rat-hole miners from Madhya Pradesh.

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.

They began the drilling from inside the pipes, 800- and 900-mm in diameter, pushed inside the tunnel to evacuate workers, on Monday as reported by HindustanTimes.

“Three of us will go inside the tunnel, one will do the drilling the other will collect muck and the third one will push the muck through the trolley,” Rakesh Rajput, one of the rat-hole miners from Madhya Pradesh, said. “The 41 men are also labourers and we all want to bring them out.”

Rat-hole mining is a primitive method of extracting coal deposits through narrow, horizontal passages, prevalent in Meghalaya. 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.