Abstract: The impacting of the movement of ore or rock in a vertical orepass on the stored materials could ram the loose materials，draw the suspension arch and the blockage of orepass.On the basis of summing up the movement characteristics of ore or rock in vertical orepass，the energy conversion and dissipation characteristics of the whole process of material movement are analyzed，the mechanism and the process of moving ore or rock impact-ramming on stored materials in the orepass are discussed，and the comprehensive measures for preventing impact-ramming are given combined with an example on mines.The study results show that:①when the ore or rock block falls in a vertical orepass，the impact energy on the stored materials at the orepass bottom is proportional to the height of the ore or rock falling and the quality of the falling ore or rock block；②the impact force of falling ore or rock is transferred between ore or rock blocks in the orepass formed a “force chain” effect，the greater the impact force，the greater the ramming degree and scope of densification，the ramming range is inversely proportional to the velocity of the energy dissipation in the impact process；③the effective measures to prevent the impact-ramming of the material stored in the orepass is controlling the size of ore or rock entering the orepass and reducing the falling distance of ore-rock blocks in the orepass.

Key words: Underground mining, Vertical orepass, Ore or rock movement, Energy transformation, Stored materials in orepass, Impact ramming