Experimental Study On Seepage Law Around The Diversion Conduit Of Ionic Type Rare-earth Ore In-situ Leaching

Nowadays,the theoretical study of seepage law of the diversion conduit is lacking,then the corresponding technical guidance is lacking,which leads to lay diversion conduit by experience,at the same time due to crack leakage,resulting in a considerable part of the leachate lossing,making the rare earth recovery rate is low,which brings great harm and pollution to the mining area.Therefore,it is of great significance for calculating the recovery rate of the rare earth resources in-situ leaching to master seepage law of the diversion conduit.In this paper,seepage law around the single and dense diversion conduit was analyzed by using the in-situ leaching model.Firstly,the pore water pressure distribution in the horizontal direction and the relationship between recovery rate and leekage of the single diversion conduit were used to analyze the seepage law around the single diversion conduit;Secondly,using the fractal theory,the fractal expression pore water pressure distribution in the horizontal direction of the single diversion conduit was proposed,and the measured pore water pressure distribution was fitted by it to determine the fractal parameters;Finally,the horizontal water pressure distribution law,the control process of the recovery rate and variation law of hydraulic gradient in the horizontal and vertical directions under different spacing and different initial head conditions of the dense diversion conduit were used to analyze the seepage law around the dense diversion conduit,considering the influence of the ratio of horizontal and vertical hydraulic gradient on the liquid collection rate,which provided a reference for reasonably determining the conduit spacing.Conclusions were as follows:(1)The pore water pressure distribution law in the horizontal direction was forming a substantially symmetrical descending funnel on both sides of the diversion conduit,the pore water pressure value was lower near the diversion conduit,while the pore water pressure value was higher far from the diversion conduit,the closer the diversion conduit was,the faster the pore water pressure decreased,and quickly close to the diversion conduit,the bottom curvature was very small,the water line was gentle,the influence range of a single diversion conduit was 22 centimeter.(2)According to fractal theory,assuming that the channel of water horizontally entering the diversion conduit was the ubiquitous 2-branched tree network structure,based on Hagen-Poiseuille equation,the fractal expression of the pore water pressure distribution in the horizontal direction and the calculation method of its parameters of the single diversion conduit were proposed,then the indoor model test showed that the expression was effective and feasible.(3)With the increasing of the initial water head,the length ratio of the pipe at each level of the tree-like branched network gradually increased and the increasing range was smaller and smaller,but the diameter ratio and the length of the primary pipe gradually decreased,then became stable,diameter ratio of the pipe at all levels was stable at 0.84.(4)Analyzing the fundamental factor influencing recovery rate of the diversion conduit was the hydraulic gradient,variation law of hydraulic gradient in the horizontal and vertical directions under different spacing and different initial head conditions of dense diversion conduit,considering the influence of the ratio of horizontal and vertical hydraulic gradient on the liquid collection rate of the diversion conduit,it was concluded that when the ratio of horizontal and vertical hydraulic gradient reached 2.26,the maximum liquid collection rate reached 73.7%.