ArchiveTaking a domestic uranium mine as the research object, a three-dimensional geological initial model of the deposit was constructed by the basic data such as drilling location, inclinometry, samples, and lithology for geological exploration of the deposit, and the resource reserves of the deposit were estimated. According to the deposit exploration, production exploration, and mining processes, the three-dimensional geological model, resource types, and development status of the ore bodies/blocks were dynamically updated. The logical relationships among three-dimensional models of mineral deposits at different times was constructed to realize the automatic monitoring of mineral resource retention, changes, and reasons for changes, in order to grasp the background of mineral resource quantity. The research on resource utilization was carried out, the annual and cumulative leaching rates was calculated, the recoverable reserves (confirmed reserves) of ore bodies/blocks were predicted based on mining production data, and the targeted resource utilization plans for different ore bodies/blocks were proposed accordingly to improve the resource utilization efficiency of the mine.
The previous studies of Mengqiguer uranium deposit centred on the directing exploration work and summary of metallogenic regularity. There are few studies on groundwater hydrodynamic field in upstream and downstream of the mining area affected by in-situ leaching. It is found that the linkage between groundwater level and seasonal variation is not obvious in the process of uranium exploration outside the mining area. These changes are quite different from the understanding of the natural flow field of groundwater in the previous exploration process. Previous studies have shown that the groundwater level throughout the deposit varies seasonally. In view of this, this paper analyzes the influence of in-situ leaching mining on the groundwater system of Mengqiguer deposit by collecting the hydrogeological data in the exploration stage and the actual measurement. Through the analysis, it is concluded that the upstream of the in-situ leaching mining area is not affected, the underground water level in the mining area is slowly declining, and the underground water level in the downstream of the mining area continues to decline. This study can provide a new idea for the understanding of groundwater hydrodynamic field in the process of uranium exploration outside the mining area, and also provide data reference for in-situ leaching of uranium.
In order to improve the production efficiency of mining enterprises and reduce production costs, choose west of Mengqiguer uranium P0 prospecting line as the pilot to study the layout principle and construction technology application of exploration and mining combined engineering. The practice shows that compared with the traditional construction process, the combination of exploration with mining not only achieves the purpose of geological exploration, but also meets the needs of mining and metallurgy production, and achieves the optimization of time benefit, economic benefit and environmental benefit.
Aiming at the optimization problem of ore blending for multi-metal in open-pit mine, a multi-objective optimization mathematical model for ore blending of multi-metal in open-pit mine is established, which takes the minimum ore grade deviation and the lowest production cost as the optimization objectives, and comprehensively considers various constraints such as production capacity of ore point, ore output, ore grade, oxidation rate, equipment production capacity and quantity, lithology and beneficiation process requirements. A multi-objective optimization method for ore blending of multi-metal in open-pit mine based on SPEA2 and entropy weighted TOPSIS is proposed. The method is applied to the optimization of ore matching in Shangfanggou molybdenum mine. The results show that compared with the original ore blending plan, the ore grade deviation of the optimized ore blending plan is reduced by 73.60%, and the production cost is reduced by 20.99%.
Taking the stope of a uranium mine as the research object, based on the characteristics of the ore body and existing engineering experience, the upward horizontal slicing mining method is selected. The mining scheme model with different stope structural parameters is established by using the numerical method of FLAC3D. Through the numerical simulation of the stope mining and backfilling process, the temporal and spatial evolution characteristics of the stope stress field, displacement field and plastic zone are analyzed. The stability of stope is studied. The results show that the horizontal stratified height of 2 m is safer and more stable than 4 m, especially in the early mining period. With the development of mining operations, the stress concentration area of the stope gradually expands, and there are obvious stress areas through the top and bottom of the mining area. With the progress of backfill, the distribution of compressive stress inside the backfill body is more uniform, showing a small compressive stress, and the stress change amplitude is not large in the later period. The displacement at the intersection of roadway and stope is the largest, and in the early stage of mining backfill operation, the growth rate is fast and the near-vertical jump growth occurs. The displacement changes at the middle part of roadway and the top plate in the middle part of stope show phased changes, and the overall displacement is small.
In response to the problems in resource reserve management, combined with the actual situation of a certain open-pit uranium molybdenum mine, a mining software management platform is adopted to establish the basic database and spatial model of the mine, and estimate the benchmark number of dynamic resource reserve management. Based on production data such as borehole measurement, sampling, ladder plane, and slope geological logging, establish and update multi-dimensional engineering information spatiotemporal data, construct different spatiotemporal relationships between ore bodies or blocks and the entire deposit, as well as algorithms for their area, shape, thickness, length, resource reserves, etc., and then reconstruct ore body or block models and estimate resource reserves, automatically realizing visualized dynamic management of resource reserves. The visualization and dynamic management of resource reserves can guide mining production in a timely manner through the rapid exploration and mining comparison, and can also provide services for the production exploration, mining design, and improvement of production planning of unexplored ore bodies or blocks. This management method has achieved good results in the production process of open-pit uranium molybdenum mines.
In order to promote the full utilization of in-situ leaching uranium resources, statistical analysis was conducted on the thickness of ore bodies, filter length, and effective thickness of ore layers in a research area of an in-situ leaching uranium mine in Inner Mongolia. The three-dimensional mining software was used to construct a geological model and mining model of the ore body. Through visual comparison of three-dimensional entities, the location of the "residual difficult ore body" outside the leaching range was accurately grasped, and the remaining resource amount was estimated. The results show that the remaining resource amount was considerable and needed further research. Using the price method to calculate the economic indicators of the deposit, conducting a technical and economic evaluation of the deposit, using the calculated economic uranium per square meter as a threshold to constrain the resource model of the "residual difficult ore body" outside the leaching range, and generating an economic block model. Using the inverse distance power method to estimate the resource quantity of the economic block model, the resource quantity of the uranium per square meter above the economic indicators is estimated. Through research, the precise location, remaining resources, and economic viability of "residual difficult ore bodies" outside the vertical leaching range within the research area have been mastered, achieving economic evaluation of the remaining resources of in-situ leaching mines.
The calcination process in uranium dioxide production is a crucial link that affects the indicators (tetravalent uranium) of uranium dioxide products. The mechanism of decomposition and reduction of AUC to produce UO2 is discussed, and the main factors and control measures affecting the tetravalent uranium content in the product are identified. It is found that the oxidation of UO2 leading to unacceptable tetravalent uranium levels cannot be directly measured but is a significant factor. Common reasons for tetravalent uranium levels being unacceptable, such as material abnormalities, equipment failures, and abnormal operations, are summarized. Equipment failures and abnormal operations are particularly prone to causing the oxidation of UO2 leading to unacceptable tetravalent uranium levels. Therefore, the weak points in the quality of natural uranium dioxide product mainly lie in equipment failures during the calcination of AUC and abnormal operations in the cooling process.
In the majority of reactors, a proportion of the combustible neutron poisons is incorporated into the fuel rods with the intention of increasing their burnup depth, thereby extending the operational lifespan of the core and enhancing the economic efficiency of the process. Erbium (Er) is a common combustible neutron poison, and in order to address the issue of on-line monitoring of the Er elemental content during the production of such fuel rods, a solution must be found. A novel approach, namely Prompt Gamma-ray Neutron Activation Analysis (PGNAA), is employed, which is well-suited to large-volume samples and can be detected online. Utilising the americium-beryllium (AmBe) isotope neutron source and high-purity germanium to establish an experimental measurement platform, with erbium oxide (Er2O3) selected as the sample. This is also combined with the MCNP to perform simulation calculations. The results demonstrate that the mass and the net area of the characteristic peaks of the sample exhibit a linear variation after correction for neutron self-shielding. The mass detection limit of the platform for erbium was 24.2 g, with a relative standard deviation of 3.65% and a relative error of 3.47%. The accuracy and precision were affected by the statistical fluctuations inherent to the data set. Subsequent optimisation of the equipment will enhance the accuracy and precision. The results demonstrate the feasibility of this method for online monitoring and establish a foundation for the subsequent use of thermal neutrons to measure the elemental content of erbium and to correct the neutron self-shielding effect of large-volume samples.
The history of uranium mining & metallurgy industry in China is reviewed, and the status of radioactive waste management system and waste disposal are introduced. On basis of analyzing the existing problems, the basic idea, work target, key tasks and guarantee measures of uranium mining & metallurgy waste management are put forward, which can provide guidance for science management of uranium mining & metallurgy waste in the future.
Against the background of growing global energy demand, the rate of extraction of various types of mineral resources is accelerating. However, with the increase of mining depth, the problem of high temperature and heat damage is gradually highlighted. The high temperature and heat damage not only affect the normal operation of various types of machinery and equipment, but also pose a serious threat to the safe production of the mine. The causes and effects of heat damage in mines were analyzed. At the same time, taking a hard rock uranium mine in the south of China as an example, through numerical simulation and other methods, the thermal and physical parameters of the surrounding rock of the mine, the geothermal field of the mine and the deep thermal environment were studied in depth, and on this basis, the existing problems of the mine were analysed, and the cooling technology was proposed.
The safety of uranium tailings pond is especially important, while static and dynamic mechanical characteristic of uranium tailings is the basement of safety analysis and evaluation of tailings pond. This paper took one of southern uranium tailings pond as research target, and by means of function fitting and picturizing, systematically studied the regularity of space-time distribution of uranium tailings layers, as well as transformation law and inner mechanism of physical, mechanical and dynamic characteristic of uranium tailings, including indexes such as density, void ratio, coefficient of consolidation, filtration coefficient, internal friction angle, cohesion, dynamic modulus of elasticity, dynamic shear modulus and damping ratio. The result can provide an important guiding significance for the construction, operation and safety analysis of uranium tailings pond.
Uranium tailings pond is a major safety and environmental hazard, and it is very important to ensure the safety and reliability under all conditions (including extreme disaster condition). Seismic condition is an important extraordinary working condition affecting the safety of uranium tailings ponds. Focused on the renovation project of a uranium tailings pond, the three-dimensional dynamic finite element method is applied to simulate and analyze seismic condition of uranium tailings pond for the first time. HS small model and UBC3D-PLM model constitutive model are selected to simulate and analyze a uranium tailings pond by dynamic finite element method. Seismic wave characteristic parameters and tailings dynamic characteristic parameters are taken into the finite element seismic dynamic simulation calculation, and the extreme conditions of rare earthquake are considered in the calculation, the displacement nephogram, acceleration nephogram, acceleration time history curve, potential liquefaction range and incremental displacement nephogram are obtained. The results show that the displacement of the dam body increases continuously under earthquake action, and the displacements of dam body decrease obviously after the implementation of the renovation project; there is no obvious change in the acceleration response caused by the renovation project; the liquefaction area is mainly distributed in the slope of the filled dam below the rock-filled platform, mainly in shallow layers (depth of about 3~6 m), and the improvement of liquefaction is limited. The stability safety factor of the dam body under rare earthquake increases from 0.975 to 1.061, the security of rare earthquake condition gets fundamental improvement.
Hard rock uranium mines are an important part of China's natural uranium production capacity. Due to policy adjustments, many hard rock uranium mines are currently in a maintenance state. Production facilities such as ore mining and hydrometallurgy processes are stopped, and only tailings(slag) storage, wastewater treatment and other waste treatment facilities maintain operation. There is a significant difference in radioactive waste emissions from the production period, with an overall reduction in the number and release of source items, and significantly reducing the radiation impact on the surrounding environment and the public. After the shutdown of a typical hard rock uranium mine, the radon concentration and individual dose contribution values decreased by 25.4% to 44.5%. Based on the characteristics of the source terms during the maintenance period, optimization suggestions for environmental protection measures during the maintenance period of hard rock uranium mines are proposed to further reduce the source terms. At the same time, an adjustment plan for effluent and environmental monitoring is provided to ensure timely detection of problems while reducing manpower and increasing maintenance workload, ensuring the radiation safety and controllability of the shutdown mines.
Some uranium mining and metallurgy soil 226Ra background value can not be determined, because of historical background and decommissioning knowledge in the early year. Based on analyzing the influencing factors of soil 226Ra value, natural factors determine soil 226Ra background value and human factors cause the soil 226Ra value to rise. It is difficult to investigate soil 226Ra background value at the contaminated site. In order to reduce the influence of human factors, monitoring plan, minimum sample size, and investigation statistical method are researched from surrounding soil of the site. Based on an example of the uranium mining and metallurgy decommissioning site, the feasibility of the supplemental investigation method is verified. The investigation statistical method can provide support for the engineering design and practice of uranium mining and metallurgy decommissioning.
The radioactivity of investigation, analysis and evaluation of liquid effluent such as mine water, tailings pond effluent and process wastewater produced by a uranium mine were conducted, the radioactivity level of liquid effluent and the pollution of accepted water were mastered, and the radiation impact of liquid effluent on local residents through various pollution channels was evaluated. The results show that the discharge concentrations of U, 226Ra, 210Pb and 210Po in the mine water, process wastewater and tailings pond effluent meet the limit requirements. The concentration of U in the middle and lower reaches of the accepted water body is slightly higher than the background level, and the concentrations of 226Ra, 210Pb and 210Po are among the normal background levels. The maximum personal dose caused by liquid effluent from uranium mine was 1.45×10-3 mSv/a of 20 km, and the maximum collective effective dose was 2.35×10-4 man·Sv/a of 20 km. The key resident group was the population group of WNW orientation in the >2~5 km area. The liquid effluent of uranium mining is discharged into the receiving water after reaching the standard, which has little impact on local radiation.