Experimental study on optimization of ore-drawing parameters for fine-grained tailings dams constructed by upstream method

Due to the fine particle composition of tailings and the addition of flocculant in the concentration process, the hydraulic sorting is weakened during the flow and deposition of tailings slurry, and dry beach can not be formed, resulting in lower stability of upstream-method tailings dams. The problem of optimizing the ore-drawing parameters of fine-grained tailings is studied based on the example of a lead-zinc tailings dam in China. Based on the sedimentation mechanism of tailings, the sedimentation and rheological characteristics of slurry are tested. The critical separation concentration of tailings slurry is preliminarily selected as 28%. Then, the upstream-method model tests are carried out in the 55 m-long horizontal sedimentary model flume to analyze the effects of slurry concentration and discharge rate on the tailings sediment sorting, the deposited beach slope and the physical and mechanical properties of the tailings. The drawing parameters optimized by the model tests are applied to the actual tailings dam, and good results are achieved, which fully verifies the effectiveness of the laboratory model tests. The method for preliminary determination of the critical slurry concentration by one-dimensional settlement and rheological property tests and model tests of a large sedimentation model flume is proposed to further determine the optimal drawing parameters, which has important engineering practical value for the optimization of drawing technology of fine-grained tailings dams by upstream-method.