A banned mining technique was used in the rescue operation for 41 workers trapped in the collapsed Silkyara tunnel in Uttarakhand. The rat-hole mining technique that began at the tunnel on Monday, November 27, and concluded on Tuesday, November 28, successfully extracted all 41 workers.
Despite delays caused by a malfunctioning auger machine from the US, the 'rat-miners' took over the last phase of the mission. The machine drilled for roughly 47 metres before breaking down, and the rest of the total 60 metres of debris had to be cleared first by the miners themselves before proceeding with their mission.
They manually drilled and removed debris to facilitate the laying of pipelines and the safe evacuation of the trapped workers. Drilling commenced within 800 and 900 mm diameter pipes at 7 pm on Monday, achieving a breakthrough around 7.05 pm on Tuesday evening.
Munna Bhai, a rat-hole miner, explaining the process to reporters said, “Our four teams were working 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. We kept digging for almost 24 hours,” he said.
The National Disaster Response Force (NDRF) personnel were deployed to use a steel chute pushed into the drilled passage to bring out the workers one by one. The workers were then made to lay on wheeled stretchers pulled by rescue personnel.
Rat-hole mining, a manual drilling method prevalent in Meghalaya, became necessary when heavy machines failed during the operation. This method involves skilled workers digging narrow pits into the ground, typically just wide enough for one person.
After the pits are dug, miners descend into the holes using ropes and bamboo ladders. This practice, typically employed for coal extraction, is considered highly dangerous. It’s banned in several countries as miners succumb to asphyxiation, oxygen deprivation, and hunger. It was banned in India by the National Green Tribunal in 2014. The individuals involved in the Uttarakhand operation were not professional rat-hole miners but just experts on the method, said nodal officer Neeraj Khairwal.