Rat Miners Key in Uttarkashi: ‘Unscientific’ Method Paved Way for 41 Workers | Options that Didn't Work

Centuries ago, poet Rahim had said that one should not forget smaller things simply because there are bigger options as one cannot use a sword where you need a needle. These lines seemed aptly fit for the Uttarkashi tunnel collapse, where an “unscientific" method — rat hole mining — came to the ultimate rescue of the workers when all big machines failed.

In 2014, the National Green Tribunal (NGT) banned rat hole mining, saying it was “unscientific" and “unsafe for workers". Ten years down the line, the same practice helped save 41 workers who were stuck inside an under-construction tunnel since November 12.

THE NATURE OF THE PROBLEM

Earlier this month, 41 workers got trapped after debris fell in a 60-meter stretch on the Silkyara side. The collapse occurred in the tunnel between Silkyara and Barkot.

Over the past few days, various government agencies tried a number of methods to make a path for the stuck workers, but everything failed. Before rat hole mining, the authorities were hopeful that a heavy-duty auger drilling machine would help make the passage. However, despite overcoming a number of hurdles over the past few days, even auger failed on Friday.

The ultimate 10 metres of the rubble were cleared after rat hole mining experts were called in. They used hand-held tools in a confined space to create a passage. The authorities are expecting the rescue work to be completed by Tuesday evening.

WHAT IS RAT HOLE MINING?

Rat hole mining basically means digging small-pits, about three-four feet deep, just large enough for one individual, to extract coal from narrow, horizontal seams. The practice was most prevalent in Meghalaya due to the difficult terrain and nature of coal available in this region.

While it has proved deadly in several cases, particularly during the rainy season, when water flooded into the mining areas, the practice helped in this case.

THE OPTIONS CONSIDERED SO FAR

While the horizontal boring by National Highways and Infrastructure Development Corporation Limited (NHIDCL) with an American auger machine was being considered as the fastest method, the authorities explored at least five different ways for the rescue. All possible ways – vertical, horizontal, perpendicular drilling and drift tunnel options — were being worked upon.

Each of these methods had a different timeline and challenges: