Flow Microbalance Simulation of Pumping and Injection Unit in In Situ Leaching Uranium Mining Area

Abstract

In situ leaching (ISL) uranium mining technology is an in situ mining technology in which the chemical solution is injected into the ore-bearing strata through drilling wells, and the solution moves along the ore bed by controlling the hydraulic gradient of the flow field and reacts with the ore to form uranium-bearing solution. To reduce leaching dead angle in the process of leaching, each pumping and injection unit should achieve uniform leaching at the end of production, and appropriate pumping and injection mode should be adopted for pumping and injection wells of each unit in the mining area. In this paper, on the basis of the actual production data of a sandstone uranium mine, we established the unit flow model of ISL uranium mining area by using GMS software. The unit flow balance of 72 boreholes in the whole mining area was analyzed and optimized through the model. The concept of flow microbalance of pumping and injection unit in the mining area is put forward for the first time, and the calculation equation of supply and receive the flow of pumping and injection well is determined. The calculation and analysis process of flow microbalance of pumping and injection unit in mining area is established. The simulation results showed that the application effect of the model was good, and the correlation coefficient of the solute transport model reached 0.8.

Hydrodynamic Simulation of the Influence of Injection Flowrate Regulation on In-Situ Leaching Range

“…The transport of solutions in in-situ leaching uranium-bearing aquifers is controlled by three fields: the hydrodynamic seepage field formed by the hydraulic gradient of the extracted liquid; the solute dispersion field formed by the leaching agent under the effect of the concentration gradient; and the physicochemical reaction leaching field formed by the chemical reaction between the leaching agent and the ore. The interaction of the seepage, dispersion, and leaching fields promotes the migration and diffusion of the solution, which constitute the in-situ leaching uranium flow field [9]. The leaching reagent and solution move continuously under the action of this flow field, forming a time-varying spatial range in the formation.…”

“…The well-site comprises two types of wells, a pumping well and an injection well, and the edges are all injection wells. Zhang et al [9] put forward the theory of "unit flow micro-balance in mining area". Moreover, by adjusting the unit pumping flow, the flow field shape can be changed, and the range of leaching can be controlled.…”

“…The in-situ leaching uranium flow field is a coupled flow field composed of groundwater hydrodynamic, solute dispersion, and chemical reaction fields [9]. The natural groundwater flow system depends on the hydrogeological conditions of the deposit itself, while the pumping liquid flow system is an artificial flow field controlled by humans, the latter of which is the key to determining the size of the leaching range.…”

Analysis of Natural Groundwater Flowing into the Flow Field of In Situ Leaching Mining

“…With the development of computer technology, numerical simulation has become an essential quantitative method to study groundwater flow conditions [3][4][5][6][7][8][9] and has been widely utilized in the in situ leaching of uranium. The numerical simulation can be used to quantitatively calculate water flow conditions in the flow field of in situ leaching mining and analyze related characteristics and regularities [10][11][12][13][14][15][16]. Tan et al [17] researched the multiprocess coupling and the movement of the reaction front during in situ leaching mining and formed relevant theories.…”

“…Wang et al [21], Zhou et al [22], Liu et al [23], and Xie et al [24] used the tracer technique to study the migration characteristics, solution migration range, and control mode of the fluid and related ions during the in situ leaching of uranium. Zhang et al [16] first proposed the flow microbalance of pumping and injection units in the in situ leaching of uranium and analyzed all pumping and injection units at an in situ leaching mining area in Inner Mongolia.…”