In-situ leaching (ISL) of uranium, a core technology in China's uranium mining, faces significant challenges due to pore blockage caused by clay minerals and pyrite, which severely restricts leaching efficiency and production capacity. This paper systematically reviews the causes and mechanisms of blocking phenomena in acid leaching, alkaline leaching, and "CO₂ + O₂" neutral leaching processes. It reveals that clay minerals induce pore blockage through physicochemical interactions such as swelling, ion exchange, and argillization of non-clay minerals, while pyrite oxidation generates sulfate and iron ions, leading to permeability reduction via mineral precipitation and colloidal adsorption. Current unblocking technologies primarily employ inhibitors to suppress pyrite oxidation, chelating agents to immobilize iron-containing precipitates, and swelling suppressants to mitigate clay mineral expansion. However, challenges remain, including lack of specificity, limited environmental compatibility, and insufficient long-term stability. Future research should focus on elucidating the synergistic mechanisms of clay-pyrite interactions, developing intelligent unblocking materials with targeted functionality, and establishing ecological risk assessment frameworks. These advancements aim to drive innovation in green and efficient unblocking technologies, providing theoretical and technical support for China's large-scale uranium base construction and sustainable nuclear energy development.

The Wuyishan metallogenic belt is an important uranium and polymetallic metallogenic belt in China, and the Aozibei deposit in Jiangxi Province, located in the northwestern part of the Hecaokeng uranium ore field within this belt, is one of the key deposits in southern Jiangxi. To investigate the uranium-gold coupling mechanism of the Aozibei deposit, this study conducts a systematic analysis based on a comprehensive review of previous exploration achievements, integrated with mineralization relationships, distribution characteristics, and geophysical-geochemical exploration data including gamma-ray surveys, ²¹⁰ Po sampling, and magnetic surveys.The results indicate that the uranium-gold coupling in this deposit is controlled by multiple factors such as mineralization stages and structure-lithology. The uranium mineralization zone of phase IV is a composite high-field area for gold, with a positive correlation between uranium and gold grades, reflecting a strong "cogenetic and syn-process" coupling. In contrast, gold mineralization is not significant in the uranium mineralization zones of phases I, II, and III. Gamma-ray residual anomalies often overlap with gold anomalies, ²¹⁰ Po anomalies, and magnetic anomalies, and the multi-parameter overlapping areas are identified as the optimal target zones for combined uranium and gold exploration. This study clarifies the metallogenic association between uranium and gold in the Aozibei deposit, providing theoretical support and practical basis for the combined exploration of uranium and gold in similar deposits within the Wuyishan metallogenic belt.

The leaching rate is an important indicator for measuring the in-situ leaching efficiency, it is also an important basis for assessing its technical level. A uranium deposit in Inner Mongolia is mined by acid in-situ leaching process, which is divided into eastern and western mining areas. In recent years, the operation shows that there is a large difference in leaching rate between the eastern and western mining areas, and the leaching rate in the eastern mining area is significantly lower than that in the western mining area. In this paper, the geology, hydrogeological characteristics, mining development technology and operation mode of the eastern and western mining areas of the deposit were systematically analyzed, and the results show that the ore body close to the waterproof floor of the ore-bearing aquifer is more conducive to the leaching of uranium in the ore layer than the "suspended" output. The permeability coefficient of the deposit gradually increases from west to east, and the permeability coefficient of 1 ~ 5 m/d is relatively more conducive to the leaching of uranium in the ore layer than that of 5~10 m/d in the most favorable range of the permeability coefficient of 1 ~10 m/d. Independent acidification was adopted in the western mining area, and the acidity of the leaching agent was increased to 14 m/d, which oxidized U (IV) to U (VI) and placed the ore-bearing aquifer in a favorable chemical environment for uranium leaching, which significantly improved the leaching effect compared with the eastern mining area, which had obvious advantages. The research results can provide a useful reference for the leaching of similar in-situ leaching sandstone-type uranium deposits.

A uranium deposit in Xinjiang adopts the "CO₂ + O₂" neutral leaching process.When treating the leachate with a fixed bed, the resin's adsorption capacity is reduced with the increase in operating time, and there are problems such as long leaching and transformation operation cycles, and poor process connection. To solve this problem, the research has been conducted on the integrated process of resin saturation readsorption, hydrochloric acid transformation regeneration and water elution. The analysis reveals that resin pollutants mainly contain elements such as Ca, Fe, Al, etc., and industrial hydrochloric acid can effectively detoxify them. This integrated process utilizes low concentration acidic qualified solution to disturb ion exchange equilibrium, promoting the conversion of to and achieving saturation readsorption; the resin is transformed into chlorouranyl type and activated with hydrochloric acid transformation; during water washing, asρ(Cl^-) decreases, gradually dissociates into . The results show that this process increases the resin capacity by more than twice, improves the leaching efficiency by 37 %, shortens the operating time by 58.3 %, and reduces the cost of hydrometallurgy by 61 700 yuan per ton of uranium, achieving the synergistic operation of resin detoxification, regeneration transformation, and uranium leaching. The integrated process provides an efficient solution for the "CO₂ + O₂" neutral leaching and uranium hydrometallurgy.

This study investigated parameter optimization for heap leaching of a low-grade uranium ore from Namibia deposit through systematic column leaching experiments. Mineralogical composition analysis shows that the uranium ore contains a high proportion of high acid consuming gangue minerals, with tetravalent uranium accounting for 68 %. The main uranium minerals are easily leached uraninite and coffinite. The uranium is enriched of in the fine-grainedportion. After crushing to-8 mm, the mass fraction of fine-grained uranium at -0.425 mm reaches 15.09 %, and its uranium grade is as high as 0.032 %, which leads to the deterioration of direct heap leaching permeability and requires acid-agglomeration pretreatment. Column leaching experiments established the optimal parameter combination : irrigation rate of 20 L/(h·m²), heap height of 9 m, aciddosage for pre-agglomeration of 20 kg/t, binder dosage of 125 g/t, and initial leachate acidity of 100 g/L H₂SO₄. Under optimized conditions, the irrigation duration is shortened to 55 d, and the uranium extraction rate is increased to 80 %. This study has demonstrative significance for the development of similar low-grade, high acid consumption, high fine-grained, and high tetravalent uranium resources.

To improve the extraction efficiency of uranyl ions in a moving bed adsorption tower and reduce the loss of saturated resin, a geometric model incorporating key internal components was established using a coupled CFD-DEM approach, with model reliability validated against experimental data. Systematic simulations of particle settling under varying inlet flow rates were conducted, focusing on the kinetic behavior at the optimal flow rate. Based on these findings, structural optimizations were implemented, and the particle flow and collision characteristics before and after optimization were compared. The simulation results indicate that the particle settling process can be divided into three distinct stages: initial uniform settling, accelerated directional transport, and energy dissipation deposition. Local vortices induced by the liquid distribution device predominantly govern particle spatial distribution, leading to accumulation in the bottom region of the tower. At the optimal flow rate, over 90% of particles reside in the low-velocity range, indicating significant collective stability within the system. Particle contact statistics reveal that wear risk primarily stems from particle-particle collisions rather than particle-structure interactions. Comparative analysis of different flow rates demonstrates that velocity markedly influences particle collision frequency and energy by altering the flow field kinetic energy. While the optimized design improves particle distribution uniformity, it also results in a slight increase in collision energy, highlighting a trade-off between flow homogenization and collision dynamics. This study elucidates the microscopic mechanisms of particle transport and wear in moving bed adsorption towers, providing a theoretical basis for the optimization of devices and the regulation of operational parameters.

The selection of mine development plans is a complex process involving multiple factors and indicators. In order to reduce the influence of subj ective j udgment on the selection of mine development plans, taking a uranium mine well as the research object, a fuzzy comprehensive evaluation model was established based on the fuzzy mathematics theory, the fuzzy weights of 10 influencing factors were determined, and the influence degree of the development plan was quantified. Based on the fuzzy judgment weight matrix and the relative membership degree matrix, and in accordance with the principle of fuzzy mathematics comprehensive evaluation, the optimal development method is determined from the initial development schemes of fuzzy clustering. Through fuzzy comprehensive evaluation, the optimal main and auxiliary shaft development schemes are determined as the vertical shaft and vertical shaft development scheme. According to the different hoisting methods of the mines, a technical and economic comparison was conducted on the two proposed schemes. The comparison results recommend that the centralized hoisting schemes of the two mines be adopted as the mine development schemes.

The block caving is one of the most efficient mining methods for large, thick, and fragmented ore bodies. However, the draw control process is strongly affected by ore fragmentation, grade mixing, and variations in geological conditions, which often results in ore loss and dilution and consequently constrains resource recovery and economic performance. To address these issues, a draw planning and management system for block caving was developed with the aim of improving draw control efficiency and economic benefits through systematic planning, intelligent decision support, and visualized production management. The system was developed using a platform-plugin software architecture and a three-layer framework consisting of a presentation layer, a core application layer, and a data layer. It integrates three key functional modules, including scheme design, draw planning, and production management, and employs PostgreSQL with spatial data extensions to enable unified data storage and efficient access. Field application results show that the system stabilizes the daily ore grade at approximately 0.32 %, with intraday grade fluctuations controlled within ± 0.01 %, and increases the resource recovery rate by about 0.5 %. Based on the designed production capacity and metal price, the annual reduction in metal loss is estimated to be approximately 92.22 million CNY. These results demonstrate that the proposed system provides effective decision support for block caving draw control and exhibits strong engineering applicability and promotion potential.

To address the issues of high development-to-extraction ratio, high cost, and low efficiency in the original mining process of a thin vein uranium deposit, a high-sublevel deep-hole continuous and synergistic mining method for thin veins has been developed. Compared with the original mining method, the stope production capacity of the new method has increased by 380.3 %, while the direct mining cost has decreased by 56.29 %. Meanwhile, to verify the safety and stability of this mining method during extraction in irregular veins, a study was conducted based on the ore veins in -200 m to -250 m level. The stability during extraction under both static and dynamic blasting loads was investigated using FLAC3D numerical simulation software. The static simulation results show that the maximum tensile stress in the ore pillar is 0.46 MPa, which is less than the tensile strength of the rock mass (1.63 MPa). The overall displacement does not exceed 1.14 cm, indicating no significant deformation. The plastic zone does not penetrate the barrier pillars and crown pillars, ensuring the stability of the stope. In the dynamic blasting load simulation, a simplified triangular dynamic load was applied to the mined-out Stope 1 #. The maximum tensile stress in the ore pillar was 0.38 MPa, indicating a stable state. The cyclic loading caused a maximum displacement of 2.6 cm in the ore pillar, with a maximum vibration velocity of 20 cm/s. Additionally, the extent of the plastic zone in the ore pillar was limited. Through numerical simulations analyzing stress, displacement, plastic zone, and vibration velocity, it has been demonstrated that the stope pillars remain stable, indicating the strong practicality of the new mining method. The research results provide technical support for the efficient and safe mining of thin-vein uranium deposits.

In the oxygen injection process of "CO₂ + O₂" in-situ leaching uranium, oxygen is prone to bubble coalescence and flow regime deterioration during long distance transportation, which in turn induces gas blockage, resulting in intermittent liquid injection, and decrease in leaching efficiency. To reveal the mechanism by which bubble size evolution regulates flow stability, this study designed a visualization experimental system for static mixers used in in-situ leaching uranium. Particle shadow velocimetry (PSV) was employed in combination with multi-stage image processing techniques—including Gaussian filtering, adaptive threshold segmentation, and morphological reconstruction. To achieve high resolution in-situ observation of micro bubble size, distribution and dynamic behavior. The results show that as oxygen concentration increase from 15 mg/L to 700 mg/L, microbubble diameter (d₅₀) rise from 528 μm to 823 μm. Conversely, increasing water flow rate from 0.5 m³/h to 2.0 m³/h, microbubble diameter (d ₅₀) reduce from 945 μm to 412 μm, indicating significantly enhance dispersion capability. With rising oxygen concentration, the flow patterns evolve sequentially from fog flow, through bubble flow and transition flow, to slug flow. In the slug flow pattern, the big bubbles periodically collapse, leading to frequent gas blockage issues on-site. This study demonstrates that the proposed image processing method provides highly reliable data for microbubble size distribution, coalescence frequency, and flow pattern identification, offering a solid foundation for process optimization and control of oxygen injection in in-situ leaching uranium.