In this study, we carried out the experiment to identify the size and size distribution characteristics of dustp articles which are generated by the work process of coal preparation plant (hammer crusher, vibration screen, belt-conveyor and feeder). As a result, the dust, which has slow deposition velocity, is verified on average97.64% as the size less than 20㎛ of the particles from 0.5 to 100㎛ and the residence time in the air is long. In the dust collection design, the collection of dust less than 20㎛ is considered desirable and efficient in terms of the air environment or the human body`s damage, but whether the only respire able dust between the 0.5㎛～5㎛, which is the most harmful to the human body, will be collected, or the particles, the working environment in mind, will be collected, it gets up to each company`s choice to operate the coal preparation plant of the mine. These results are applicable to the facility`s design and construction as the basis documents.