Analysis on Breaking Causes of Middle Pans of Scraper Conveyor in Fully-Mechanized High Cutting Coal Mining Face

According to the easy breaking problem of the middle pans in the scraper conveyor of a 7 m high cutting coal mining face in Bulianta Mine, the motion tr aces of the middle pans were analyzed and the performances were obtained. According to the main performances of the middle pans in the scraper conveyor, a pressur e test was conducted on the related stressed conditions, the material composition and mechanical performances of the middle pan were compared and the main breakin g causes of the middle pan were obtained. The results showed that the actual breaking and deformation results of the middle pan were ftted to the results of the finite e lement analysis. The pressure test analysis showed the max stress location of middle pan. When the pressure increased to 4 330 kN, the convex head of the middle pa n and the transition part of the pan sidewall would be in a cracking tendency. Meanwhile, the middle part of the concave head in the dumbbell key seat would be in a cr acking tendency. An element analysis was conducted on the breaking part of the middle pan. The analysis showed that an overhigh content of Si, Mn, Cr, P, Mo and oth er element would directly affect the hardness of the middle pan and could cause the easy breaking of the middle pan.