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.

In response to the issues such as significant differences in dynamic water levels among different drilling wells in a test mining area, insufficient groundwater recharge, unbalanced unit extraction, and varying leaching rates, this study employs automated monitoring of dynamic water levels as a focal point. By carrying out dynamic groundwater level monitoring, we aimed to achieve a visualized system for groundwater dynamics. Utilizing computer digital processing and simulation technology for the analysis of monitoring data, we established a quality control system centered on numerical simulation of the leach flow field, study of flow field characteristics, optimization of extraction flow rates, and regulation of groundwater levels. We developed scientific techniques for flow field regulation, enabling reasonable distribution of leaching agents, reducing areas of dead zones in leaching, enhancing the smoothness of the flow field in the mining area, and improving unit extraction conditions, thereby laying a solid foundation for intelligent and refined analysis of the mining area.

With the continuous improvement of automation levels in uranium mines, the reliability of electrical control systems has become a key factor in ensuring production safety and efficiency. This paper addresses the abnormal failure issues of the frequency converter control system in a uranium mining project in Xinjiang and proposes a PLC-based frequency converter communication control and hardwired backup redundancy control scheme. By comparing and analyzing the technical characteristics of terminal control and communication control, a redundant architecture combining Modbus RTU and terminal control is designed and implemented. Practical application shows that this scheme effectively solves the control failure issues caused by communication interference in the original system. The mean time between failures (MTBF) of the system has increased from 168 h before the transformation to over 2 000 h, and the control response time has been shortened to less than 100 ms. The research content provides an important reference for the design of high-reliability control systems in the uranium mining industry, especially for production scenarios with complex electromagnetic environments and stringent reliability requirements.

To address pipeline blockage issues in the negative-pressure pneumatic conveying of uranium dioxide at a uranium company, this study employed a combined approach of CFD-DEM coupled simulation and field experiments. By examining particle flow patterns, gas-phase pressure distribution, and system pressure drop, the underlying mechanism of pipeline blockage was elucidated. The validity of the simulation model was confirmed through comparative analysis of field measurements and numerical results. The findings demonstrate that increasing the elbow curvature radius from 200 mm to 500 mm and the bend diameter ratio from 2.50 to 6.25 significantly reduced local pressure losses during conveying. As a result, particle flow stability improved, with the peak gas-phase pressure dropping to 27.2 kPa and the overall system pressure drop decreasing markedly, thereby restoring normal operation of the power equipment. This study verifies the reliability of the CFD-DEM model for optimizing the pneumatic conveying system of uranium dioxide particles, offering both theoretical support and practical guidance for achieving efficient and stable transport.

To address the challenges in the design of associated radioactive waste repository and ensure the long-term effectiveness of waste disposal, theoretical and experimental research were conducted on radionuclide migration control technologies for associated radioactive waste disposal sites. A three-dimensional pollution control technology system was established from three dimensions: source, process, and end. Through waste leaching experiments, stabilization agents were screened, and based on this, a new type of stabilization composite material was developed, which effectively resolved the acid rebound issue to a certain extent, achieving source control. Research on seepage process blockage constructed a three-dimensional waterproof intrusion system, blocking external water intrusion from multiple dimensions. For end-of-pipe pollution control technology, soil modification and retardation experiments were conducted using natural clay from a specific region, determining the optimal mixing ratio of modified materials and the thickness of the natural material anti-seepage layer.The practical applications were implemented for a provincial associated radioactive waste repository, and the results show the three-dimensional pollution prevention and control technology plays a critical role in controlling radionuclide migration.

Uranium tailings produced by mining and smelting contain residual radioactivity, and the released radon gas is harmful to human. Covering control is an effective means to inhibit radon. In order to solve the problems of insufficient long-term stability and high cost of traditional covering materials, this study proposed multi-layer covering system based on alkali-activated solidification materials for uranium tailings, and carried out the trial in a tailings pond in the south of China. The selected sodium silicate (with a modulus of 2.0) as the alkali activator, mineral powder as the active material, and river sand as the fine aggregate, determined the optimal mix proportion as mineral powder : solid sodium silicate : uranium tailings (1.25-1.60 mm): river sand : water = 0.8 : 0.2 : 1.4 : 0.6 : 0.5 (mass ratio), with a compressive strength of 10.6 MPa for the solidified body at 28 days. With the alkali-activated solidified body of uranium tailings as the radon shielding layer, the test shows that the radon reduction efficiency of the 5 cm thick alkali-activated solidified body reaches 97.85 %. The multi-layer covering system constructed with the alkali-activated solidified body of tailings as the radon shielding layer consists of a protective layer, a vegetation layer, a radon shielding layer, a drainage layer and a barrier layer, which has functions such as corrosion resistance, seepage prevention, radon reduction, etc., and the radon excretion rate after covering is stable within 0.187-0.419 Bq/(m³·s), which meets the national standard. This system has excellent resistance to wind erosion, rainwater scouring and differential settlement and has good long-term stability. Economic analysis shows that the material cost of this system is only 75% of the same system at home and abroad, and the local of uranium tailings to achieve resource recycling has both environmental benefits and economic advantages, providing an efficient and feasible technical scheme for the decommissioning and treatment of uranium tailings pond.

China's associated radioactive waste residues are wide-ranging in origin, diverse in type, and large in quantity, which has begun to constrain the healthy development of the associated radioactive mineral industry. There is an urgent need to build scientifically standardized repositories for long-term disposal. On the basis of reviewing domestic and international disposal approaches for associated radioactive solid waste, and by analyzing the geological conditions, storage capacity, investment costs, safety assurance, construction conditions, and operation and maintenance of a specific disposal repository as well as the suitability of different disposal methods, then proposing a repository construction scheme with high feasibility.

To solve the problems of large subjectivity, empirical, time-consuming, laborious and low efficiency of manual interaction in the design of open-pit mine slope road, a parametric three-dimensional design method of open-pit mine slope road is proposed. The general idea is: combining with the requirements of open-pit mine slope road design parameters, using parametric slope road design ideas to construct a mathematical model for parametric three-dimensional design of open-pit mine slope road. The research results were developed and realized in the digital mining software platform, and the generated road parametric 3D design model was used for an open-pit mine slope road design. The experimental study shows that the average time for completing the design of a single open-pit mine slope road is 3 h for manual interaction, and 5 min for parametric 3D design method, and the proposed parametric 3D design method of the open-pit mine slope road greatly reduces the workload of the design technicians, and accommodates the rapid automatic updating after the design parameters change. The proposed parameterized 3D design method of open-pit mine slope road greatly reduces the workload of design technicians, adapts to the rapid automatic update after the change of design parameters, and greatly improves the rationality of the design results.