The objective was to evaluate disposal requirements for solid wastes from power stations burning low-rank western coals. Samples of wastes from process development programs were tested in the laboratory. Measurements were selected to characterize waste materials with respect to their disposal properties. This volume presents results of physical and chemical tests carried out on four fly ashes collected from tests of a fluidized bed combustion process carried out at the Grand Forks Energy Technology Center. Other volumes present results of characterization of solids from dry scrubbing processes and from wet scrubbers employing alkaline fly ashes as FGD reagents. Regulations promulgated under the Resource Conservation and Recovery Act of 1976, as amended, require that disposal practices pose no reasonable probability of adverse effects on health or the environment. Laboratory tests indicated that fly ashes from atmospheric fluidized bed combustion (AFBC) of coal would be classified as nontoxic and therefore nonhazardous. These tests indicated that AFBC fly ashes can be disposed of as nonhazardous wastes. However, compositions of leachates from these solids indicated that leachates from disposed wastes have some potential to contaminate surface water and groundwater. Disposal practices should be designed so that no leachate or runoff from exposed wastes is released directly to surface waters. In addition, generation and release of leachate should be controlled so high quality groundwater resources are protected. Specific designs required to achieve these goals will vary from site to site. Current technology should be adequate to develop environmentally and economically acceptable disposal options. 16 figures, 16 tables.