Abstract: Coal is the major energy source and provides about 40 percent of the total electricity production of the world .For Australia it is nearly 80%. Meeting up global demand for less emission of GHS, Australia is seeking alternative ecofriendly renewable energy sources. In Australia, there is huge range of fossil fuel resources (especially deep seated coal deposits, which are difficult to extract with conventional mining) and the policy makers are seeking "clean coal" technology for further usages of the resources. CSG (coal seam gas) and UCG (underground coal gasification) are identified technology for exploiting those coal deposits. The UCG is much more effective process for energy exploitation (theoretically greater than 15-20 times) compared to CSG process. Demonstration of UCG projects and development of these technology received momentum as one of the successful project at Chinchilla, Queensland, Australia is operating successfully from 1997 to 2013 for power generation. Last few years there was a debate for choosing priority policy for CSG or UGC. Australian local entrepreneur and global IOCs sought for massive scale CSG extraction and presently this industry is in booming stage. Apparently it is seen from the industry trend for UCG operation is behind the race compared to CSG activity. But the future prospect of UCG is bright, as we can say for adopting policy "First CSG later on UGC; can't be CSG after UCG operation, as there left nothing exploitable in the coal body". The ideal conditions of the coal body are deviated while CSG operation is being done. Very minor amount of hydro-carbon (in-situ natural gas) are extracted but major share of the coal deposit are left over at deep geological formation. Even there is a provision for simultaneous operation of the both in the same block. Review on the existing and developing sophisticated technology for next phase of abandoned CSG fields is a potential area for further R&D. The success of this effort can enlightened the black coal towards "Cleanest and Greenest" source of energy for next generation Hydrogen fuel.