Rat hole mining, a controversial and outlaw mining practice is back in the spotlight nearly nine years after it was banned by the National Green Tribunal (NGT) over severe environmental impacts and unsafe labour conditions.

The rat hole mining technique is being used to extract the 41 construction workers trapped inside a collapsed Uttarakhand tunnel after modern machinary failed to execute the rescue operation.

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So, what is this rat hole mining?

Rat-hole mining is an illegal coal mining practice which is commonly reported in Meghalaya. Since it’s ban in 2014, the practice is still being used behind closed doors in some parts of Meghalaya.

It involves the drilling of holes to extract small quantities of coal. It is considered a primitive method that involves digging holes ranging from five to 100 square metres to reach the coal seams.

When NGT banned the rat hole mining, it claimed the practice is “unscientific”. However, despite the ban, the coal mining practice still remains rampant in several parts of Meghalaya.

Under the technique, miners dig a narrow tunnel which allows one individual to go inside and extract the coal. Since the tunnels just fit one person, the are called rat holes.

How rat hole mining has helped in Uttarakhand tunnel rescue operation?

The state-of-the-art American auger machine drilled roughly 47-48 meters of a horizontal tunnel. After that, it’s driller tool broke inside the drilled passage and authorities said that the damage was beyond repair.

The rescues teams then resorted to manual drilling – a safer but time consuming option. However, they brought in a team of rat hole mining experts who completed the remaining task in less than two days.

Earlier it was reported that manual drilling of the tunnel could take around 4-5 days more.

The rat hole miners went inside the steel pipe being pushed inside the rubble through which trapped workers will be pulled out and drilled a horizontal passage. The process was somewhat similar to the digging of a narrow tunnel for coal mining.

As per the latest reports, less than three meters of drilling was left to reach the trappe workers and the remaining work is expected to be completed by today.