Underground Coal Gasification is the conversion of solid Coal to gas in-situ by heating the coal and injecting oxidants air/oxygen to cause the gasification by partial combustion instead of complete combustion of coal. UCG is the promising technology having a lot of health, safety and environmental advantages over the conventional mining techniques; the major motivational aspects of UCG involves increased worker health & safety by using no man underground, no surface disposal of ash and coal tailings, low dust and noise pollution, low water consumption, larger coal reserves exploitation, and low Volatile organic components, methane and greenhouse gases emission to atmosphere. UCG is an inherently clean coal technology as it reduces deadly sulphur and nitrogen oxide emissions to very low levels. It is the only coal power generation technology that can virtually eliminate mercury air emissions and capture most of the coal mercury content in a concentrated form that can potentially be sequestered from environmental release. Total solid waste from UCG is typically half the volume generated by conventional coal plants and water use is substantially lower as well.