In order to further study the mechanical properties and pore structure evolution of sandstone under the action of liquid nitrogen freezing and thawing cycles, the sandstone in natural water-bearing state and saturated state were taken as the research object. The compressive strength, elastic modulus, pore T₂ map and nuclear magnetic porosity of sandstone after different liquid nitrogen freezing and thawing cycles were measured by nuclear magnetic resonance instrument and rock mechanics test system. The mechanical properties, porosity evolution and pore size distribution of sandstone under the action of liquid nitrogen were analyzed. Based on the SDR permeability model, the permeability change of sandstone after freezing and thawing cycles was calculated. The results show that the uniaxial compressive strength of sandstone decreases significantly after liquid nitrogen freezing treatment, and the decrease of strength increases with the increase of freezing and thawing cycles. When the number of cycles increases from 0 to 5, the decrease of compressive strength in natural state increases from 12.25% to 29.04%, while the maximum decrease of compressive strength of sandstone in saturated state is 55.50%. The results of nuclear magnetic resonance (NMR) test show that the freezing and thawing cycle of liquid nitrogen significantly increases the porosity and permeability of sandstone, especially for sandstone samples in saturated state. After five freezing and thawing cycles of liquid nitrogen, the porosity growth rate is 39.09%; and the permeability growth rate reaches 160%, which is 1.89 times that of natural water-bearing sandstone. The research results can provide a new idea for the efficient leaching of low permeability sandstone-type uranium deposits by liquid nitrogen fracturing technology.

Over the past few decades, China's uranium resource mining and metallurgy technology has undergone a development process from nothing to something, and from weak to strong. It has introduced trackless mining and "three-under" mining technologies, broken through surface heap leaching and underground heap leaching, innovated in-situ blasting leaching and bacterial heap leaching, practiced acid, alkaline and neutral in-situ leaching of uranium mining technologies, explored and improved borehole drilling, underground leaching methods and hydrometallurgical processes, built digital mines in Xinjiang and Inner Mongolia, verified the control of leaching area, the treatment and reuse of waste drilling mud, reverse osmosis treatment of waste liquids, and the groundwater remediation of decommissioned test mines, and implemented the rational mining and metallurgy of uranium-molybdenum and uranium-coal deposits, and explored the technology of extracting uranium from seawater. The new technologies and processes practiced in uranium resource mining and metallurgy have become the driving force for China's natural uranium production. Looking to the future, China's uranium resource mining and metallurgy industry is bound to innovate and create greater breakthroughs.

The development of nuclear energy plays a vital role in the adjustment of national energy structure and environmental sustainability. The stable supply of natural uranium is essential for nuclear energy development. Given China's relatively limited terrestrial uranium reserves, extracting uranium resources from the vast oceanic territories holds significant strategic value. However, the complex and variable marine environment presents considerable challenges for conventional adsorbent materials and technologies to effectively separate uranium at extremely low concentrations, necessitating the urgent development of specialized adsorbent materials for uranium extraction from seawater. In recent years, researchers domestically and internationally have developed numerous uranium separation materials and conducted promising practical trials under seawater conditions. This review comprehensively summarizes the latest research progress in various seawater uranium extraction technologies based on the characteristics of different adsorbent materials, addresses the multifaceted technical challenges encountered in uranium extraction under real seawater conditions, and provides insights into future prospects for the development of uranium extraction technologies from seawater.

Uranium is a strategic mineral resource in China, and geophysical logging plays a crucial role in sandstone type uranium exploration. This study applies various commonly geophysical logging methods to prospect for uranium in the Chepaizi area of the Junggar Basin. Beginning with the logging instruments and methods, we determine favorable prospecting horizons within the Shawan Formation, Taxihe Formation, and Tuguru Group based on statistical analysis of gamma logging result and radioactive background value across different strata and sections within the study area. The 128 Regiment section, as well as its north and southwest parts, are identified as favorable areas for prospecting. Additionally, comprehensive study and interpretation of geophysical logging parameters allow for accurately divide borehole lithology. Abnormal responses from spontaneous potential (SP) curves suggest a relative relationship between drilling fluid and formation water salinity. When combined with apparent resistivity curve analysis, geochemical characteristics of high-salinity formation water within the Shawan Formation target layer are obtained. High-salinity water of Shawan Formation is conducive to oil and gas accumulation, and their migration provide favorable conditions for uranium reduction enrichment and mineralization. Overall, the application of geophysical logging in Chepaizi area proves beneficial for uranium metallogenic analysis and prospecting in this area.

For the precise quantification and calculation of solid mineral resources and reserves, this study utilizes data from exploration projects, mining design, and engineering surveys during the exploration and development of solid minerals. By employing three-dimensional (3D) digitalization methods and visualization techniques, we have constructed 3D geological attribute models, designed mine-out models, and 3D excavation engineering models. Furthermore, we have integrated the statistical computation of resources and reserves with these 3D entity models, proposing a 3D statistical computation method and data management framework specifically tailored for solid mineral resources and reserves. The findings indicate that the application of 3D digitalization methods enables accurate and detailed accounting and computation of resources and reserves and production ores, precise classification of resource reserve types, and dynamic updating of resources and reserves based on the continuously expanding information of ore body control points, thereby enhancing the efficiency of dynamic management of solid mineral resources and reserves. Practical application cases have further confirmed the feasibility and effectiveness of the 3D digital dynamic management method for solid mineral resources and reserves.

Gamma logging is the fundamental method for quantitatively determining uranium content of mineralized intervals in boreholes. The U-Ra equilibrium in a certain sandstone-hosted uranium deposit has been severely disrupted. To investigate the impact of Ra-rich sections (mineralized intervals where the equivalent uranium grade derived from radium is ≥ 0.010 0% but the uranium grade is<0.010 0%) on log interpretation and U-Ra equilibrium correction results, the uranium and radium content analysis results of permeable ore samples were systematically studied. The results show that: for samples with a uranium grade≥0.010 0%, the weighted average uranium grade is 0.042 7 %, the weighted average U-Ra equilibrium coefficient is 0.615, and the coefficient of variation is 1.041; for samples with an equivalent uranium grade derived from radium≥0.010 0%, the weighted average uranium grade is 0.029 5%, the weighted average U-Ra equilibrium coefficient is 0.890, and the coefficient of variation is 3.785. Ra-rich sections will significantly increase the deposit's U-Ra equilibrium coefficient, increase the orebody thickness, and decrease the deposit's uranium grade. Gamma logging cannot identify and remove Ra-rich sections. Consequently, neither the log interpretation results nor the U-Ra equilibrium correction results objectively reflect the orebody's spatial position, grade and thickness. The estimated resource quantity is also inaccurate.

The ore-bearing aquifer in a sandstone-type uranium deposit in Xinjiang has poor permeability and small amount of water in the well. When using the "CO₂ + O₂" neutral leaching process, it is difficult to add oxygen, and the oxidation efficiency of U (Ⅳ) in the ore is low, resulting in a low leaching rate of uranium resources. To solve this problem, an efficient micro-nano oxygenation device was developed. The results show that this device can add oxygen steadily and continuously to the low permeability and low water well. Under the condition that the leaching agent is supplemented with NH₄ HCO₃ and the CO₂ concentration is unchanged, compared with the traditional single well oxygenation, the concentration in the leaching solution increased by 35.95%, the oxidation capacity of the ore layer was increased, the oxygen consumption was reduced by 20.16%, and the monthly leaching rate was increased by 60.00% during micro-nano oxygenation.

This paper focuses on the "CO₂+O₂" in-situ leaching uranium process of the Qianjiadian uranium deposit, and conducts an in-depth investigation into the relationship between filter length, leaching recovery rate, and operating water volume. Actual field data are used for analysis, and the results show that there is a strong positive correlation between filter length and operating water volume: the operating water volume increases significantly in the filter length of 7-11 m, with an average growth rate of 5.2% per meter; while the growth slows down in the filter length of 12-18 m, with an average growth rate of 1.3% per meter. In contrast, a strong negative correlation is observed between filter length and leaching recovery rate: the leaching recovery rate decreases gently in the filter length of 7-11 m, with an average decline rate of 0.75% per meter; the decline accelerates in the filter length of 12-14 m, with an average decline rate of 2.0% per meter; and it drops sharply in the filter length of 15-18 m, with an average decline rate of 3.67% per meter. Based on the above analysis, it is determined that the optimal filter length range for the "CO₂+O₂" in-situ leaching uranium process of the Qianjiadian uranium deposit is preferably 7-9 m. For ore segments with larger ore body thickness, the filter length can be appropriately adjusted within the range of 16 m, but shall not exceed 16 m.

In the leaching liquid system of a uranium deposit in Xinjiang, the content ofρ(Cl^-) is high and the mineralization degree is high. When using traditional D382 weakly alkaline anion exchange resin to treat this system, the dynamic adsorption capacity of uranium is low (15~30 mgU/mL)and the uranium separation and enrichment efficiency is poor. This study systematically evaluated the adsorption performance of JH-1 macroporous weakly alkaline acrylic resin on the system. The results show that J H-1 resin has special tertiary amine functional groups and a macroporous skeleton structure, exhibitingexcellent selectivity for uranium complexes and in CO₂ +O₂ neutral leachate. Its saturated adsorption capacity reaches 60 mgU/mL, which was 2.6 times higher than that of D382 resin. In the dynamic adsorption process, the adsorption efficiency of JH-1 resin for uranium reaches 98.85%, the leaching efficiency is 99%, and the uranium recovery rate is 82%. This resin effectively solves the problem of resin adsorption site competition and equipment scaling in high mineralization systems by suppressing the interference of competitive ions such as Cl^- and .It significantly reduces the consumption of raw materials such as hydrochloric acid and industrial salt, and reduces production costs by 23 000 yuan/tU, providing technical support for efficient development of sandstone uranium mines.

With the continuous development of in-situ leaching uranium mining technology, how to effectively remove solid particles has become a key issue of in-situ leaching uranium mines. In this paper, the removal method of solid particles in an in-situ leaching uranium mine was studied in depth, and the process was optimized. Firstly, the principle of in-situ leaching uranium process was summarized. The sources of solid particles and their negative effects on production were described in detail, such as increasing the operating pressure of the system, reducing the permeability of the ore layer, and affecting the efficiency of uranium recovery. Then, the existing solid particle removal methods were analyzed. On this basis, a series of optimization strategies for solid particle removal process were proposed, including improving resin cleaning cycle, optimizing resin tower sequence, and increasing discharge process in adsorption process. Through experimental research and practical application case analysis, it is verified that the optimized process has significant effects in improving the removal efficiency of solid particles and improving the stability of system operation. The research results provide important technical support for the efficient production of in-situ leaching uranium mines.

One of Kazakhstan's paleo-channel sandstone uranium deposit has reduced uranium concentrations (15-20 mg/L) and over 50% of wells exceeding their service life, affecting economic performance and sustainability. To address these problems, technical measures were implemented: used oxidants during acidification to boost uranium concentration peaks and maintain higher levels; established a ful-life cycle quality management system to increase the service life of drilling wells; carried out advanced exploration to increase indicated and measured resources; and remined the low-recovery or multilayered orebodies. The results show these measures effectively improve resource recovery, lower operating cost, and extend mine life, supporting economic feasibility and sustainable operation.

Current uranium mining and metallurgy equipment faces significant shortcomings in perception, control, communication, and machine intelligence. This paper systematically elaborates on the dedicated equipment system for the entire process from mining, hauling, beneficiation, to hydrometallurgy of both hard-rock and sandstone-type uranium deposits. Based on this analysis, differentiated upgrade paths were proposed. Representative achievements, such as the group-well water-level Fabry-Perot cavity sensor system, the underground intelligent ore transfer system for mined rock, and the ultra-high-lift leaching solution pumping system, demonstrate the implementation of a closed-loop framework integrating sensing, decision-making, and execution. Results indicate that intelligent technologies significantly enhance the efficiency and safety of uranium mining and metallurgy, providing strong technical support for the efficient development of uranium resources in China.

Plate-type nuclear fuel is extensively employed in small modular reactors, where the incorporation of neutron poisons into fuel elements enhances fuel utilization efficiency. Hafnium (Hf), a commonly used neutron poison, is widely applied in nuclear fuel assemblies. To ensure the operational safety, the accurate quantification of neutron poison content is of great significance. In this study, the detection of Hf was investigated using Prompt Gamma-ray Neutron Activation Analysis (PGNAA). A PGNAA system comprising a D-T neutron generator and a high-purity germanium detector was established to measure Hf plate samples. The system achieved a mass detection limit of 3.89 g for Hf. Furthermore, a Monte Carlo simulation model of the measurement system was developed to calculate the characteristic gamma rays induced by neutron excitation. The calculated results deviate from the experimental measurements by less than 10%, thereby validating the model's reliability. These findings provide both experimental and theoretical support for the application of PGNAA technology in measuring Hf content in nuclear fuel elements.

In response to the large amount of uranium containing wastewater generated during the mining and processing of uranium resources, two types of edible mushroom processing waste, Velvet Antler Mushroom Feet (VAMS) and Red Bamboo Fungus Cap (BFP), were used as biological adsorbents to investigate their removal performance of U (VI) in aqueous solutions. The effects of acidity, adsorption time, initial uranium concentration, solid-liquid mass-volume ratio, coexisting ions and temperature on the U (VI) adsorption performance of edible fungus processing waste were systematically investigated by the static batch method. The results show that under the conditions of pH=5.0 and temperature of 25 ℃, the maximum adsorption capacities of VAMS and BFP for U (VI) are 24.34 mg/g and 23.88 mg/g, respectively, with removal rates reaching 97.7% and 91.8% accordingly. Moreover, Ca²⁺ has the strongest interference effect on the adsorption of U (VI).VAMS and BFP reach equilibrium at 2 hours and 4 hours, respectively, and conform to the pseudo-second-order kinetic model and Freundlich isotherm model. This indicates that the adsorption process is mainly dominated by multi-molecular layer chemical adsorption. The thermodynamic parameters (ΔG<0, ΔH>0) confirm that the adsorption is a spontaneous endothermic reaction. Combined with the characterizations of SEM-EDS, FT-IR and XPS, the adsorption of U (VI) by VAMS mainly relies on the coordination of hydroxyl groups on the material surface, while the adsorption of U (VI) by BFP mainly depends on the coordination of nitrogen-containing functional groups on the material surface. The research results not only indicate that edible mushroom processing waste has good adsorption performance for uranyl ions, but also realize the resource utilization of agricultural waste, providing a low-cost and environmentally friendly adsorption material for the treatment of uranium containing wastewater, which has important application value.

Continuous sampling and analysis of characteristic pollutant concentrations were conducted on the wastewater from a closed uranium mine discharge outlet and surrounding surface water from 2020 to 2024. The monitored characteristic pollutants included U, ²²⁶Ra, ²¹⁰Po, ²¹⁰Pb, Cd, Mn, As, and pH. Using the Mann-Kendall test to analyze the spatiotemporal distribution characteristics of characteristic pollutants in wastewater, and using the Nemerow Index method to evaluate the ecological risk of surrounding surface water. The results show that during 2020—2024, the concentrations of characteristic pollutants in wastewater and surface water meet the limit requirements, and the concentrations of U, ²²⁶Ra, Mn, and As in surface water are generally higher than those in the control points. The Mann-Kendall test results indicate that from 2020 to 2024, the concentrations of U, As, and Cd in the wastewater discharged from uranium mines are effectively controlled and show a significant downward trend. The ecological risk analysis of monitoring data from six surface water sampling points using the Nemerow Index method shows that the pollution factors that have a significant impact on surface water are U natural, ²²⁶Ra, and Mn. In the process of long-term monitoring of the closed uranium mines, the focus is on the concentration changes of U, ²²⁶Ra, Mn, and As in wastewater, as well as U, ²²⁶Ra, and Mn pollution factors in downstream surface water.

This paper studied the investment and management strategies of major global uranium mining companies and summarizes the insights and recommendations for Chinese uranium mining enterprises in the uranium market. Selecting six major uranium companies, including Kazatomprom, Rosatom, BHP, Cameco, Paladin Energy and Orano, as research subjects, analyzed their strategic trends, exploration and development strategies, and uranium asset portfolios. The study found that during periods of low uranium prices, these companies improved profitability through technological innovation, cost reduction, production cuts, halting high-cost mines, and securing long-term contract prices. During the uranium price recovery cycle, these companies quickly adjusted their strategies, increased investment in risk exploration, and restarted suspended mines, leading to significant growth in revenue and net profit. Based on these experiences, this paper proposes the five recommendations. First, uranium mining enterprises should enhance their understanding of industry cyclicality and optimize their asset portfolios. Second, they should continue to increase investment in uranium-rich countries to enhance resource control. Third, they should flexibly adjust production strategies and produce on-demand to stabilize spot market prices. Fourth, they should pursue diversified development through comprehensive mining operations. Lastly, they should continuously increase exploration investment to prepare for future resources.

Associated radioactive solid waste is generated by associated mining enterprises during mining, beneficiation, and smelting processes. If not stored properly, it may pose potential radiation safety risks to the environment. To effectively assess the radiation impact on operators during the loading, unloading, and stacking of associated radioactive solid waste, this paper selects the waste storage process of an existing temporary storage facility for associated radioactive solid waste as an example. The radiation hazard factors evaluated mainly include γ rays generated by the decay of natural radionuclides in the associated solid waste and ²²²Rn generated by the decay of radionuclides. The evaluation results show that the γ radiation dose rate at external attention points of the waste temporary storage facility is less than 2.5 μGy/h, and the maximum annual radiation dose to operators does not exceed 4.1 mSv/a, which is in compliance with relevant regulations. The results indicate that after adopting certain shielding and ventilation measures in the associated solid waste temporary storage facility, the radiation dose to operators can be effectively controlled, reducing radiation safety risks.

In order to grasp the radioactive level and its changing trend around the ionic rare earth ore separation enterprise, and evaluate the potential impact of smelting separation process on the surrounding environment, this study takes a typical rare earth separation enterprise in Guangxi as an example. From 2017 to 2024, a systematic tracking and monitoring was carried out for 8 consecutive years, and the spatial and temporal distribution data of the radiation environment were obtained, and the dynamic characteristics and changing trends of the radiation environment around the enterprise were grasped. The maximum gamma dose rate around the enterprise is 104 nGy/h, and the maximum radon concentration is 69.0 Bq/m³. The specific activities of ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K in solid-state environmental samples are 36.8-88.9, 28.9-180, 27.7-107 Bq/kg, and 452-479 Bq/kg, respectively. The specific activities of ²³⁸U, ²³²Th, ²²⁶Ra, and ⁴⁰K in gaseous environmental samples are <29.8, <6.95-27.6, <6.28-27.6, and <19.3-33.5 Bq/kg, respectively. The mass concentrations of uranium and thorium in liquid environmental samples are 0.057-3.7 and 0.019-0.948 μg/L, respectively. The activity concentrations of ²²⁶Ra, total alpha, and total beta are 2.01-21.9 mBq/L, 0.017-0.123 Bq/L, and 0.027-0.099 mBq/L, respectively. The total amount of U and Th in the liquid effluent sample is 0.241-168 μg/L, and the activity concentrations of ²²⁶Ra, ²¹⁰Po, and ²¹⁰Pb are 16.2-1 870, 1.35-89.1, 2.56-96.8 mBq/L. According to the analysis of monitoring results, from 2017 to 2024, the gamma radiation dose rate and radon concentration level in the surrounding environment of the ion type rare earth separation enterprise, as well as the radioactive indicators of surface water, groundwater, aerosols, soil, and sediment, basically meet the standard requirements. The overall radiation environment around the enterprise is stable, and the obvious fluctuations in some indicators are closely related to the adjustment of sewage treatment processes. The results provide a reliable reference for the radiation environment management of associated radioactive mining enterprises.