The basic principle, major controlled process condition, mining process and its characteristics of selective leaching are analyzed. It is a clean mining process of high efficiency.

It's the carbon-energy footprint, destructive mining, diminishing supplies of clean water and exploitative labor practices -- all of which are now threatening Meghalaya, by the way.

UCG is promoted as a relatively clean method of exploiting coal seams that are too deep or thin to be tapped economically using conventional mining.