Utilization of Fly-Ash in the Backfilling of Void in Underground Mines

Coal-fired thermal power plants worldwide are encountering significant challenges in handling and disposing of the ash generated during the combustion process. The problem is further exacerbated by the high ash content (30–52%) present in Indian coal. Thermal power plants face major concerns regarding the safe disposal of coal ash and the need for large storage areas. Consequently, efforts have been made to find alternative uses for the ash, rather than simply dumping it in nearby ash ponds. One promising approach involves utilizing underground mine voids to accommodate the bulk of the fly ash. Underground mine spaces have the greatest potential for storing fly ash in large quantities compared to other possible applications. The process involves using filling materials to reinforce the surrounding rock and provide support to the overlying strata, thereby reducing surface subsidence. This paper presents a study conducted in this context, focusing on the bulk utilization of fly ash in backfilling applications. The research aimed to find viable solutions for effectively utilizing fly ash, thereby addressing the challenges faced by coal-based thermal power plants in managing and disposing of this by-product. This innovative approach presents an encouraging solution for sustainable mining practices and minimizing the environmental impact associated with coal extraction.