This report presents the activities performed and the results achieved during a two-phase investigation of the technical and economic feasibility of disposing of coal mine refuse underground in active mines. Three regions that are severely affected by coal refuse problems are southwestern Pennsylvania, southern west Virginia, and eastern Kentucky. A conceptual model mine is presented that describes the geologic conditions, mining methods, and environmental circumstances typical of each region. Procedures used in selecting the regions and in modeling typical mines are described. The report presents existing methods for stowing systems that would be appropriate for the model mine, discusses technical characteristics and environmental effects relative to the various systems, and evaluates the technical and economic feasibility of the three alternative disposal system designs. Comparisons of costs among systems and with costs of surface disposal systems are presented.