The slab beneath the Alboran Sea is a consequence of the collision between two continents (Europe and Africa), which was initiated along the northeastern Spanish coast, experienced slab rollback and migrated to the area adjacent to the two continents. The tectonic background in this area includes episodes of collisions with adjacent continents as well as extension of those basins in the western Mediterranean. Here, we present three-dimensional (3D) Kirchhoff-approximate generalized Radon transform (GRT) images to further constrain the lithospheric structures previously identified by other researchers. The GRT images were calculated from the same P-to-S (Pds or Ps) teleseismic receiver functions (RFs) as the previous common conversion point (CCP) stacking, but the GRT data provide figures with greater resolution than the Pds RFs CCP results. This study indicates that the Alboran Slab may have completely detached from the crustal base under the western Betics Mountains and that a larger range of lithospheric ‘peeling off’ developed beneath the western part of the Betics Mountains than some previous results have claimed. The observed thin lithosphere under the Middle Atlas (MA) and eastern High Atlas (HA) may have a geodynamic relationship with lithospheric delamination under the eastern part of the Rif Mountains, which has also led to the thin lithosphere under the eastern Rif. According to the thick lithosphere under the western HA, the shallow LAB under the MA and eastern HA may have no heat-flow connection with the Canary mantle plume, as stated in several previous studies.

This paper aims to quantitatively analyze the influence of natural groundwater flowing into the flow field of in situ leaching mining. The computational method was built to evaluate the effect of natural groundwater on the production efficiency of pumping wells for the in situ leaching of uranium, and the “flow ratio of groundwater” and related formulas were defined. C1 and C2 mining areas of an in situ leaching uranium mine in Inner Mongolia were taken as an example, and the effect on the “flow ratio of groundwater” when changing the flow quantity of injection wells and the position and length of the filter in the pumping and injection wells were compared. The results show that the variation in the “flow ratio of groundwater” of a whole mining area or a single pumping well in different production stages can be obtained by the neutral solution concentration value from the mining area’s numerical simulation. Regulating the position, length of the filter, and mode of fluid injection in an in situ leaching mine can control the quantity of natural groundwater flowing into the mining area and reduce the fluid exchange between the flow field of in situ leaching uranium mining and natural groundwater.

Based on simulated groundwater streamlines, researchers have developed a theoretical framework for calculating the characteristic volume of in-situ uranium leaching, encompassing both the convection volume and potential leaching volume. This framework was further enhanced by integrating it with the optimization theory of particle release. Through extensive research utilizing the genetic algorithm, a multi-objective optimization program for the flow field of in-situ uranium leaching named MOFISL was created. Consequently, an optimization system combining particle release optimization theory and MOFISL was established. Implementing the optimization system at a specific site in Bayan-Uul. We first determine the most effective method for positioning particles in the given area. Subsequently, the focus of MOFISL was directed towards optimizing the pumping volume while simultaneously minimizing external influence on the flow field, resulting in a series of Pareto optimal solutions. The results indicate that potential leaching volume is primarily influenced by the number of particles released horizontally, with minimal impact from the vertical release. While comparing edge and corner injection wells to internal injection wells, it is notable that internal injection wells have a more complex local flow field. This complexity necessitates a higher quantity of particles for accurate potential leaching volume calculations. By adjusting the weight of optimal solutions, multi-objective optimization management model for in-situ leaching of uranium offers efficient and accurate optimization methods for the decision-making process. The demonstrated adaptability and potential for future enhancements highlight the versatility of the optimization system.

Hydraulic fracturing is a key stimulation technique for enhancing the permeability of tight sandstone-hosted uranium deposits. However, existing hydraulic fracture network evaluation methods are primarily applicable to stress regimes in which the vertical principal stress exceeds the horizontal principal stress, making them unsuitable for evaluating low-angle or subhorizontal hydraulic fractures formed under high-horizontal-stress and low-vertical-stress conditions. To address this limitation, this study develops a semi-quantitative method for evaluating hydraulic fracturing effectiveness under stress regimes characterized by high horizontal stress and low vertical stress. The proposed method introduces a Stoneley-wave attenuation index and combines it with Stoneley-wave chevron-apex responses to identify hydraulically fractured intervals. By further integrating conventional well-log data to reduce interference from borehole enlargement, lithological boundaries, and natural fractures, the method supports the identification of hydraulically induced fractures and provides a semi-quantitative assessment of their development. The method was applied to a hydraulic fracturing pilot test for in situ leaching uranium mining in the Bayingobi Basin, Alxa, China, where it supported the identification of hydraulically induced fractures and fractured intervals in both stimulation and monitoring wells. Field application results support the engineering applicability of the proposed method and provide preliminary validation of its effectiveness. The results indicate that this method provides an effective logging-based approach for evaluating hydraulic fracturing performance and investigating fracture propagation in tight sandstone-hosted uranium deposits.