After all the efforts to rescue 41 workers trapped inside the collapsed Silkyara tunnel failed to make headway, a banned mining practice came to the aid of the rescuers.
The Rat-hole mining technique, which began on Monday, helped reduce the distance between the trapped workers and the rescuers as a team of “rat-hole miners” drilled through tonnes of concrete and the rubble.
As per the latest reports, the work of inserting the pipe inside the tunnel is complete and all the workers will be rescued soon.
Twelve rat-hole mining experts were involved in manual drilling and excavation horizontally through the last 10- or 12-metre stretch of debris of the collapsed portion of the under-construction tunnel on Uttarakhand’s Char Dham route.
The “rat-hole” method made quick progress and the rescuers are about to reach the 41 workers trapped in the collapsed tunnel for 17 days.
The Rescue Operation So Far?
After over two weeks of the multi-agency rescue mission, officials shifted their focus to two alternatives — manual drilling through the remaining 10- or 12-metre stretch of the rubble or, more likely, drilling down 86 metres from above.
The horizontal drilling that was being carried out by a huge auger machine failed after the machine got stuck in the rubble on Friday, forcing officials to focus on an alternative option — drilling down from above the tunnel.
The rescuers also began vertical drilling on Sunday afternoon after the auger machine failed to make any headways. About 40 per cent of the 86-metre vertical drilling required is now done.
For the horizontal through-the-rubble option, officials decided that the final stretch would be handled through a manual approach in which individual workers will go into the escape passage with drills, as well as gas-cutters to tackle obstacles like iron girders.
What is Rat-Hole Mining?
Rat hole mining is a controversial and hazardous practice of extracting small quantities of coal from narrow burrows or deep tunnels. It was prevalent in some states like Meghalaya.
The term “rat hole” refers to the narrow pits dug into the ground, typically large enough for one person to fit and extract coal, according to The Indian Express.
Once the pits are dug, miners descend using ropes or bamboo ladders to reach the end of the tiny holes. The coal is then extracted manually using tools like pickaxes, shovels, and baskets.
As per the report, there are two types of rat hole mining: side cutting, where the narrow tunnels are dug on the hill slopes and workers go inside until they find the coal seam and box cutting, where a rectangular opening is made, through which a vertical pit is dug and small rat-hole tunnels are dug horizontally to extract coal.
Risks in Rat hole mining
Rat hole mining is unregulated, lack safety measures and cause environmental concerns. There are no proper safety provisions for miners like ventilation, structural support and safety gear.
In a prominent tragic incident in 2019, 15 miners trapped inside a flooded “rat hole” coal mine died in Meghalaya’s East Jaintia Hills district, after remaining trapped for several days.
The practice has been a centre of criticism due to the dangerous working conditions, numerous accidents and environmental damage. The method of mining has been banned by the National Green Tribunal (NGT) in 2014. However, in 2019, the Supreme Court set aside the NGT ban and allowed coal mining in Meghalaya through scientific mining methods.
Why Rescuers Chose Rat-hole Mining Method?
Two teams of seven and five men who are experts in the technique of rat-hole mining were called in by two private companies involved in the rescue operation. The miners are divided into multiple teams, where each team responsible for going into the steel chute laid into the escape passage for brief periods.
Uttarakhand government’s nodal officer Neeraj Khairwal said that the men brought to the site were not rat-hole miners but people who are experts in the technique.
Rajput Rai, a rat-hole drilling expert, said earlier today that one person will do the drilling, while another collected the rubble with his hands and the third would place it on a trolley to be pulled out.
“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 miners, told Reuters.
“We have been doing it for more than 10 years and there’s enough space for us. The 41 men are also labourers and we all want to bring them out,” he added.
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