Abstract: In this paper, based on the solid material particle’s differential motion equations (displacement, velocity, acceleration) in the pipeline of fully mechanized coal mining and backfilling, the particle diameter and density of the solid material are established as the main factors which affect its motion. In addition, the effect characteristics of the two main factors to the particle motions are studied by theoretical analysis and MATLAB software. The results indicate that the solid material particle experiences a varying acceleration motion in the feeding pipeline, and the total acceleration time increase as the particle diameter and density increase. According to the engineering conditions of No. 12 coal mine of Pingdingshan Coal Group, the proper diameter of the used solid material particle should be 80 mm, the feeding system has not been blocked heretofore, and the real feeding rate can reach to 500 t/h.

Key words: fully mechanized coal mining and backfilling, feeding system, particle diameter, density, vertical feeding