Context: The rescue operation in Uttarakhand using rat-hole mining, a method banned for its hazardous nature and environmental impact, brings to light the complexities and challenges of mining practices in India.

Rat Hole Mining

• 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. 

• A rat-hole mine involves digging of very small tunnels, usually only 3-4 feet deep, in which workers, more often children, enter and extract coal. Rat-hole mining is broadly of two types – side-cutting and box-cutting.

• Rat hole mining is a method used for extracting coal from narrow, horizontal seams, and it is particularly prevalent in the state of Meghalaya.

• The term "rat hole" refers to the narrow pits dug into the ground, usually 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.

Types of rat-hole mining

Side-cutting procedure

• The side-cutting type of mining is usually done on hill slopes by following a coal seam visible from the outside.

• Coal seams: Dark brown or black-banded coal deposited within layers of rock.

• In this procedure, narrow tunnels are dug on the hill slopes and workers go inside until they find the coal seam.

• The coal seam in hills of Meghalaya is very thin, less than 2 m in most cases

Box-cutting

• It entails digging a circular or squarish pit, varying from 10 to 100 sqm in width, up to a depth of 400 feet.

• Miners who drop down in makeshift cranes or using rope-and-bamboo ladders dig horizontally after finding the coal seam.

• Once the coal seam is found, rat-hole-sized tunnels are dug horizontally through which workers can extract the coal.

• The tunnels are dug in every direction from the edge of the pit, resembling the tentacles of an octopus.

Environmental and Safety Concerns

• The mines are typically unregulated, lacking safety measures such as proper ventilation, structural support, or safety gear for the workers.

• The unregulated mining led to land degradation, deforestation, and water with high concentrations of sulphates, iron, and toxic heavy metals, low dissolved oxygen, and high biochemical oxygen demand.

• Water sources in Meghalaya rivers have turned acidic with high concentrations of toxic metals due to rat-hole mining, posing environmental challenges.

Bans by the National Green Tribunal (NGT)

• The NGT banned rat-hole mining due to safety concerns, with incidents of flooding during the rainy season resulting in fatalities.

• Despite bans by the NGT in 2014 and 2015, rat-hole mining persists in Meghalaya due to economic factors and the absence of alternative livelihoods.

Why Prevalent in Northeastern India?

• Despite the presence of coal reserves, commercial mining is not practiced in the North-Eastern regions because of terrain’s unsuitability and nature of coal deposits. 

• The coal seam is extremely thin, and methods like open-cast mining are economically unviable.

• The coal found in the North-East contains lots of sulfur and this type of coal is categorized as bad quality of coal. Thus discourages big ticket private investments.

• Being a tribal state where the 6th Schedule applies, all land is privately owned, and hence coal mining (like limestone mining) is done by private parties which do not have capacity of big investment.

• Further, these mines are considered as gold chest by the locals which provides employment and prospect of money for the population of these backward area without much investment.