Geotechnical, Environmental and Other Issues Pertaining to Fly Ash Disposal in Opencast Mine Voids

Abstract

The generation of huge quantity of fly ash and its utilization or safe disposal is the main concern affecting the efficient and economical working of thermal power plants (TPP) in India. Government of India is making continuous efforts and making stringent regulations to promote fly ash utilization and has given targets to all TPPs to achieve 100% utilization level. Despite various initiatives by Government, the utilization of fly ash is still around 63% and remaining 37% fly ash is poorly disposed off into ash ponds. Presently, major consumers of fly ash are for making cement, bricks, concrete and roads. The utilization of fly ash in all these activities has reached to almost saturation level. A very limited quantity of fly ash is being utilized by mines for backfilling of mine voids. One of the potential area for bulk disposal of fly ash is mine void filling which can help in achieving 100% utilization target. This paper discusses geotechnical, environmental and various operational and legal issues pertaining to fly ash disposal in opencast mine voids. Various methods of fly ash disposal in mine voids with successful implementation on a large scale in Indian opencast mines are discussed with a view to achieve 100% utilization target set by Ministry of Environment, Forest and Climate Change (MOEFCC), Government of India.