Silkyara tunnel collapse: Banned in Meghalaya, rat hole mining to rescue 41 trapped workers

The dangerous rat hole mining, a coal mining method supposed to be unscientific and unsafe, will now be used to try and rescue the 41 construction workers trapped inside the Silkyara tunnel in Uttarkashi for the 16th days today.

Rat hole mining commonly used in illegal coal mines of Meghalaya is now banned given the risks involved.

Experts so far have tried all sorts of scientifically applicable methods to make a breakthrough, including horizontal drilling using an American auger machine and also vertical drilling from atop the hill.

However, the persistent efforts have so far not achieved the desired success.

But now experts have opted for the most unconventional and regarded as unscientific, rat hole mining to rescue the trapped workers.

The idea is to apply this method to drill manually and remove the debris inside the 800 mm pipe of the tunnel.

What is Rat Hole Mining and what the SC said?

Rat hole mining has been already banned in Meghalaya by the National Green Tribunal (NGT) in 2014. The NGT had termed it unscientific.

Originally, rat hole mining involved digging narrow tunnels, each of which fits only one person to enter and extract coal. It is a technique that is generally used in coal mining, especially in regions that have difficult terrain.

In Meghalaya, where the practice was once rampant, has also led to a number of fatal incidents.

In January 2021, six workers lost their lives after a crane collapsed into the pit of a coal mine in the Sorkari forest. In December 2018, at least 17 labourers died when the mine they were working in at Ksan got trapped and submerged.

Considering the gravity of the situation, the NGT penalized the Meghalaya Government was fined Rs 100 crore in 2019 for failing to stop rat-hole mining, even five years after the imposition of the ban.

Worth mentioning, the Meghalaya Government had challenged the NGT ban in the Supreme Court stating that there was no other option of extracting coal from the hills as the available coal seam is too thin to mine with big machines.

But, since the efforts to resuce the trapped workers in the Silkyara tunnel is yet to see the light of the day, experts opting for the “unscientific” methodology of rat hole mining is something significant.

How the Govt plans to rescue the 41 workers now?

As per the official sources, a team of 6 specialists have reached the site to undertake the manual drilling work.

They will go inside the 800 mm pipe of the tunnel to remove the debris manually. The team includes engineers from the Indian Army’s Madras Engineering Group as well as civlians.

Apart from the drilling machine, a hammer, a shovel, a trowel, and a life support device for oxygen will be carried by these specialised teams while going inside the tunnel.

The debris was formed after the auger machine being used for horizontal drilling of the tunnel got stuck inside the pipe. It reportedly produced 48 m of debris on the mouth of the tunnel. A plasma cutter was used to cut and remove the auger machine, but the debris will have to be removed by the rat miners.

Read also: Uttarkashi tunnel collapse: BSNL steps in to provide landline phone to enable trapped workers to talk to their families