This two-phase project to study the problems of large-scale surface coal mining is an important element in the overall problems of coal conversion programs to supply the future energy needs of the United States. Mathematical models are being developed for use in both national energy planning studies (macromodels) and for new mine viability studies (micromodels). During the quarter, eight cases were analyzed in detail to test the simulation models for representative situations in the following regions: Illinois Basin--dragline area stripping, Four Corners--dragline area stripping, Fort Union--dragline area stripping, Texas Gulf--dragline area stripping, Appalachia (Ohio)--dragline contour stripping, Powder River--shovel/truck area stripping, Appalachia (West Virginia)--shovel/truck mountain top removal, and Green River--shovel/truck multiple dipping seam mining. User's Manuals were prepared describing the fifteen models developed to date.