Experimental Study On Ore Body Structur Of Ion-adsorption Type Rare-earths In Leaching And Its Applications

With the leaching ore fluid continuously flow in the ore body in the process of in-situ leaching of ionic type rare-earth, mineral particle happen migration and ion exchange, that change grain size distribution,destroy ore body structure, lead to ore body strength weakening,then cause ore body landslide. Studying the impact of leaching mining on the structure and the strength of ore body will have great guiding significance for the analysis of slope stability.In this paper,based on the constant head laboratory column leaching tests of ionic rare earth ore samples research the influence of grain size distribution and permeability coefficient of two different leaching mining way and determine the leaching mining way that minimal impact to the structure of ore body;Using GDS stress path triaxial apparatus test the cohesive force of ore samples that leaching ore before and after with 3% ammonium sulfate solution and using direct shear apparatus test internal friction angle of ore samples that leaching ore before and after to analysis of the effect of leaching mining on the strength of ore body;According to simplified model of slope that the test ore block, using Geo-studio software to calculate the critical saturation line and the safety coefficient of simplified model of the slope,through the field monitoring results to verify the feasibility using the critical saturation line monitoring slope stability. Through the above work,the main conclusions are summarized as follows.(1)Based on the laboratory column leaching tests of ionic rare earth research the influence of grain size distribution and permeability coefficient of leaching mining,the results show that the particle migration effect on the structure of the ore body is greater than the ion exchange,and the second leaching mining way, namely direct leaching ore with ammonium sulfate solution has a smaller affect on the structure of ore body and a safer mining environment than the first leaching way.(2)Leaching mining significantly lower the strength of ore body. the strength of ore body after leaching reduce step by step from seepage entrance to seepage exit. The change of the mineral composition and the increase of water film thickness casued by ion exchange reaction lower cohesion more than 50% and are the main factors to reduce the cohesion of ore body;Grain size distribution changes is the main factor influencing the internal friction angle of ore body,the more fine particle content the greater of the internal friction angle.the internal friction angle increases about 15% after leaching mining.(3)Through numerical simulation got simple method monitoring the slope stability. When seam saturation area calculated by the critical saturation line and seam saturation area calculated by field monitoring saturation line within an area of a difference of ±10%,and we thought the mine be in critical state of failure,yet according to the critical saturation line to adjust injection fluid strength,,control injection fluid,prevent landslides and ensure the safety of leaching mining.