Application And Research Of Ore-bearing Aquifer's Permeability In One Uranium Mine

In-situ leaching mining method is of one of the main methods to exploit rare metals.As its low cost of construction,good mining effect,it calls for more and more attention.In order to use in situ leaching method reasonably,we need to understand the characteristic of rock mass permeability,ore-bearing aquifer under different conditions of seepage law and its influencing factors.This paper uses the fractal theory to study the relationship between the porous medium permeability and pore structure.Formula of Derivation fractal dimension and porosity of porous media is established.Combined with empirical formula and porous medium mechanics mass conservation equation,single fractured rock mass and the intact rock permeability coefficient formula under triaxial stress state was set up.By the test of indoor,the liquid surface tension effect on rock permeability was studied.Combined with numerical simulation software of Visual Modflow,the three-dimensional groundwater seepage model was established,under the conditions of different arrangement and well spacing distribution of stope,leaching solution and the regularity of solute transport were simulated.The main results are as follows:(1)When a single fractured rock mass is under triaxial stress state,when Lateral stress increases and the normal stress is constant,the permeability law of exponential type increases.when Lateral stress is constant and the normal stress increases,the permeability law of exponential type decreases.(2)Intact rock under triaxial stress state,with the increase of stress,rock is in microcracks pressure stages in the first place;The permeability coefficient is slightly decreased than that in no stress state.Primary pore and fissure get linked gradually.(3)The size of the liquid surface tension can significantly affect the leaching liquid seepage effect in aquifer.By adding the surface active agent to the leaching liquid(sodium dodecyl sulfate,etc.)can significantly reduce the leaching liquid surface tension,permeability coefficient increases obviously,leaching effect is significantly increased.(4)Orebody width along the strike has no obvious change,the ore body is greater than the average width 150 m,the determinant and the seven good leaching effect can be obtained.But on the edge of the stope and ore body thinner area,the model can significantly eliminate leaching corner at 7 o 'clock,waste,reduce the leaching solution so mine mainly adopts type is decorated,seven local flexible pumping liquid injection Wells arrangement,can maximum limit to guarantee the quantity of products at the same time,the economic production effectively.(5)Using the model arrange at seven type,coefficient of permeability is greater than 1 m/d mine,smoke filled fluid well spacing is less than 20 m,mining efficiency is higher but the cost of production significantly increased,is not conducive to sustainable production of mine.When smoke filled fluid well spacing greater than 30 m,the production cost is low,but the production cycle is very long,leaching effect is poorer,daily production is not guaranteed.Therefore,20-30 m smoke filled fluid well spacing for optimal caliper,can produce high economic benefit and reasonable mine service life.Through the above study of Ore-bearing aquifer seepage flow and solute transport law,it helps to deepen the knowing of ore-bearing aquifer seepage law of leaching solution and the optimal design of in-situ leaching mining,provides certain theoretical basis and reference.