The primary purpose of this study was to develop emission factors for significant surface coal mining operations that are applicable at Western surface coal mines and are based on state-of-the-art sampling and data analysis procedures. Primary objectives were (1) to develop emission factors for individual mining operations, in the form of equations with several correction factors to account for site-specific conditions, and (2) to develop these factors for particles less than 2.5 micrometers (fine particulates), particles less than 15 micrometers (inhalable particulates), and total suspended particulates. Secondary objectives were (1) to determine deposition rates over the 50- to 100-m distance downwind from the sources, and (2) to estimate control efficiencies for certain source categories. Emissions resulting from the following were sampled at three mines during 1979 and 1980: drilling, blasting, coal loading, bulldozing, dragline operations, haul trucks, light- and medium-duty trucks, scrapers, graders, and wind erosion of exposed areas. The primary sampling methods was exposure profiling, supplemented by upwind/downwind, ballon, wind tunnel, and quasi-stack sampling. The number of tests run totaled 265. The report concludes with a comparison of the generated emission factors with previous ones, a statement regarding their applicability to mining operations with specific caveats and collateral information which must be considered in their use and recommendations for additional research in Western and other mines.