Longwall mining is generally recognized as safer, more productive, and more economic when compared to room-and-pillar underground coal mining. There has been, however, increasing concern for the control of airborne coal dust concentrations at longwall faces. The airborne dust cloud at a longwall face is a complex aerosol system containing particles of varied size, density, shape, and state of aggregation. For the development of more effective dust control practices at longwall faces, it is necessary to understand more clearly the characteristics of the longwall dust cloud. In this U.S. Bureau of Mines paper, results of a research study on dust concentration distribution along longwall faces are presented. The objective of this study is to characterize the longwall dust cloud behavior and provide necessary fundamental data for a better understanding of the longwall dust problem. Msa personal samplers and gravimetric total dust samplers were employed to collect respirable and total airborne dust samples. The size distribution of these samples was determined by microtrac spa. The instantaneous respirable airborne dust concentrations were recorded using ram-1. The dust concentrations are related to face operations, particularly the shearer location and activities. The size distribution of airborne dust, instantaneous respirable airborne dust concentration, and air quantity distributions along longwall faces reveal a complex dust flow phenomenon. Additional fundamental studies are needed for characterizing the temporal and spatial behavior of the dust cloud.