• The body of one of the nine workers trapped inside a coal mine in Assam’s Dima Hasao district was recovered by Army divers on the third day of the rescue operations.

• The labourers were trapped inside the Assam Coal Quarry situated in the 3 Kilo area of Umrangso, after a sudden gush of water flooded a “rat hole” mine.

• The flooding occurred all of a sudden, probably due to the opening up of an underground water channel.

• Rescue operations were launched immediately with teams consisting of local authorities, emergency responders and mining experts

• A team of Navy, Army, National Disaster Response Force (NDRF) and State Disaster Response Force (SDRF) personnel intensified their efforts to rescue the trapped miners.

• Officials have said the mine is illegal.

What is rat-hole mining?

• Coal deposited in thin seams imbedded in sedimentary rocks, sandstones and shale, is extracted manually by making narrow tunnels either through the side of the hill (referred to as side-cutting) or through a rectangular shaft/pit (known as box-cutting). 

• The tunnels being narrow are referred to as “rat holes” and the mining method is commonly known as “rat-hole mining”.

• Rat-hole mining involves digging of narrow tunnels, usually 3-4 feet high, for workers to enter and extract coal. The horizontal tunnels are often termed rat holes, as each just about fits one person.

• In side-cutting, a hole is cut from the side of the hill where coal seam is visible from outside or where there is a possibility of locating a coal seam. Through a narrow tunnel, the miners explore the inside of the hill for coal and if found, extract it manually through small implements. 

• In both side-cutting and box-cutting methods, the miners enter/crawl into the tunnel and extract the coal with a small shovel. The extracted coal is brought from the tunnel into the shaft/pit by using a conical basket or a wheelbarrow. 

• The coal is then taken out of the pit either manually or with the help of a small crane.

• Rat hole mines were once used extensively in India’s northeastern states. They were banned in 2014 because of the large number of fatalities and the damage caused to the environment.

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