Abstract: It is easy to form a super-high single-bench dump by using the slop-directed discharge technology in open-pit mines. The slope of this kind of dumping structure is in a critical stable state for a long time，and there are engineering problems such as prominent slope instability risk，obvious ecological hidden danger and high treatment cost. In this paper，the 430 m super-high single-bench dump of an open-pit limestone mine is taken as the research object，and the granular mechanics test，engineering scheme design and limit equilibrium numerical simulation method are comprehensively used to carry out the research on stacking mode optimization and descending section treatment technology. The results of ma⁃ terial screening and triaxial test show that there are significant vertical particle size differentiation charac⁃ teristics in the super-high single-bench dump. The proportion of particles with a particle size of less than 20 mm at the top of the slope is more than 35%，and the proportion of particles with a particle size of more than 40 mm at the foot of the slope is more than 40%，and the mechanical parameters of the soil are lay⁃ ered along the vertical distribution. Through the construction of new transportation roads and the optimiza⁃ tion of rock discharge sequence in different zones，the original single super-high single-bench dumping process is transformed into a composite stacking mode of pressure slope toe combined bench and covered multi-bench. On the premise of not interrupting mine production，the grading and descending section treat⁃ ment is carried out，and the original 33°~35° natural slope angle of the dump is optimized to within 30°.Fi⁃ nally，the overall slope angle of the partition is stable at 29.40°~29.89°. The results of multi-condition sta⁃ bility checking show that the safety factor of each partition slope is significantly improved after treatment， which fully meets the requirements of the specification threshold and effectively eliminates the hidden dan⁃ ger of landslide instability. In this paper，a collaborative management and control mode of“production and management”is constructed，and the slope management is completed synchronously based on the produc⁃ tion process，which greatly reduces the special management investment of mine pit closure and the pres⁃ sure of later operation and maintenance，and can provide engineering reference for the safety management and ecological management of the same type of super-high single-bench dump.

Key words: dump, super high single-bench, slope-directed drainage, numerical simulation, stack? ing mode, descending section treatment