Rat Hole Mining is a process that involves digging very small tunnels, usually about 3-4 feet deep, in which workers, more often children, enter and extract coal.
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New Delhi: Rescuers have fallen back on the rat-hole mining technique to evacuate the 41 labourers trapped in Silkyara-Barkot tunnel in Uttarakhand for 15 days, following the failure of a heavy machine to drill through the rubble to create an escape passage for them. Rat-hole mining is often associated with Meghalaya, where holes are drilled for mining small amounts of coal.
At the Silkyara tunnel in Uttarkashi, at least 12 experts have been called by Trenchless Engineering Services Private Limited and Navayuga Engineers Private limited for applying the rat-hole mining technique horizontally in the collapsed part of the main structure. “They will have to drill at least 10 to 12 metres with their own hands. They will mostly use two tools — hand-held drilling machines to remove the rubble and gas cutters for cutting the iron hurdles,” an official told PTI.
According to Neeraj Khairwal, Additional Secretary, Uttarakhand government and the state nodal officer for the rescue operation, a skilled team of workers called to apply the rat-hole mining technique will remove the rubble with their hand. “As they remove the muck, the tunnel pipe (800-mm) will be pushed gradually by the machine through the rubble,” Khairwal said.
Rakesh Rajput, another expert, said three of them will go inside the tunnel, one will do the drilling, another will collect the muck and the third one will push the muck through the trolley.
What is rat-hole mining
Rat Hole Mining is a process that involves digging very small tunnels, usually about 3-4 feet deep, in which workers, more often children, enter and extract coal.
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Meghalaya predominantly engages in rat hole mining because of the difficult terrain and nature of coal available in this region. The coal seams in Jharkhand and Chhattisgarh are thicker than those in Meghalaya, leading to fewer Rat hole mine incidents in these states. A coal seam (dark brown or black) is a banded deposit of coal located underground and may be seen within deep rock layers.
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. Once the pits are dug, miners descend using ropes or bamboo ladders to reach the coal seams. The coal is then manually extracted using primitive tools such as pickaxes, shovels, and baskets.
In the other type of rat-hole mining, called box-cutting, a rectangular opening is made, varying from 10 to 100 sqm, and through that a vertical pit is dug, 100 to 400 feet deep. Once the coal seam is found, rat-hole-sized tunnels are dug horizontally through which workers can extract the coal, according to a report in The Indian Express.
Environment and safety concerns of rat hole mining
Rat hole mining are typically unregulated, lacking safety measures such as proper ventilation, structural support, or safety gear for the workers. It can also cause land degradation, deforestation, and water pollution.
This method has faced severe criticism due to its harzardous working conditions, environmental damage and numerous accidents which also leads to fatalities.
NOTE: In 2014, the National Green Tribunal (NGT) banned it, citing concerns about its unscientific nature and the safety risks posed to workers. Despite the ban imposed by the NGT, unauthorised rat-hole mining continues, leading to unfortunate fatalities in Meghalaya.
