Fly ash and bottom ash are the waste materials obtained in enormous quantities from the coal based thermal power plants making their usage and disposal very difficult. There is a scope of utilizing these waste materials in raising ash dykes. This book presents the results of investigation carried out to assess the suitability of fly ash/bottom ash mixed with local soil for raising ash dyke. Samples of fly ash, bottom ash and soil were obtained from the power plant site and a series of laboratory investigations were carried out on mixture of fly ash, bottom ash and local soil in order to find out the optimum fly ash/bottom ash and soil ratio which will give a reasonable factor of safety against slope failure while raising ash dyke. Stability analysis of the slope was carried out by Plaxis to find out the factor of safety. This book, the authors are sure, will be very useful for research scholars and practicing engineers dealing with disposal or utilization of fly ash and bottom ash.