Seepage Law In-situ Leaching Mining Of Ionic Rare Earth And Its Application

In-situ leaching mining technology is used to exploit ionic rare earth resources mainly depending on experience. But so far, there is no uniform standard to guide in-situ leaching mining technology mining ionic rare earth. Studying the model of single port fluid injection intensity and the seepage law of the leaching ore fluid in the seam and the stability of the slope in-situ leaching mining will have important significance for standardizing the ionic rare earth mining.This paper puts forward two kinds of single port liquid injection intensity calculation model under the condition of Darcy flow and the non-Darcy flow based on Dupuit assumptions. The coefficient of permeability and seepage parameters are determined by the laboratory experiment. The single port liquid injection intensity calculation model is verified through field experiment. The seepage stability time of the test mining area in one liquid injection intensity is confirmed according to the liquid injection rate and the recycled fluid volume every day. The seepage stability time is further proved by the growth rate of the liquid level and the pore water pressure. The phreatic surface is determined by many liquid level observation holes in the mining area of experiment. And the saturated volume ratio is calculated in the period of liquid. The earth pressure gauges are installed in the slope having empty face and without free face in order to analyze the stability of slope according to the earth pressure change rule and crack growth of slope. At the same time, the saturated volume ratio is calculated when the slope is unstable. The main study results are as follows:(1) Compared single port liquid injection intensity in the field experiment with the calculation results under Darcy flow and non-Darcy flow, the results indicated that the error of the single port liquid injection intensity between measured value in the field and calculated value under the condition of non-Darcy is lesser than 15%. The calculation results can satisfy engineering requirements.(2)The seepage reached to be stable at 42 day after fluid injection when the intensity of liquid injection is 740 m3/d. And the saturated volume ratio is only 63% at this time. So, the rare earth mine of unsaturated zone is hard to be soaked in sulfate solution. And resource recovery rate is low.(3)The saturated volume ratio increases with the injection continually of ammonium sulfate solution into the seam of rare earth mine. The stretch-draw crack appears on the top of the mountain when the saturated volume ratio of rare earth mine is 20%～30%. The slope stability deviated initially when the saturated volume ratio is 55%～70%. The stability of slope toe having free face deviated initially when the saturated volume ratio is 55%～70%.