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Mechanical stability of pillars is crucial for the safety of underground engineering. Understanding the failure process of rock pillars upon uniaxial compression may help predict its failure. This study investigates the failure process of sandstone, coal and granite under uniaxial compression using acoustic emission (AE) monitoring. A developed AE method, i.e., microcrack cumulative summation curve method, was applied to identify whether tensile or shear microcracks dominated during rock deformation to failure. This method was validated through Brazilian and direct shear tests. Our results showed that a) sandstone samples experienced shear faulting failure with AE analysis indicating an initial dominance of tensile microcracks, followed by shear microcracks, likely due to grains movements and intra- and inter-granular microcrack development; b) granite samples exhibited tensile failure, with transgranular microcracks developing along the axial compression direction, intense wing microcracks, and a potential transition from tensile to shear microcracking dominating process as indicated by AE analysis; c) coal samples displayed mixed shear-tensile failure, possibly dominated by the orientation of calcite veins where microcracks initiated, developed and coalesced, as suggested by AE and microstructure analysis. Using the power-law singularity theory for failure warning, our analysis demonstrated that lateral strain and AE count can accurately predict failure times for sandstone (15 ~ 22% early) and granite (8 ~ 12% early) samples. However, this method is less effective for coal samples due to their discontinuous failure processes. Our research highlights that combining microcrack development with failure prediction analyses effectively reveals physical failure processes in typical rocks, offering practical application for mining engineering. Highlights: A verified AE microcrack cumulative summation curve method was applied to reveal the failure process of rock materials. Microcracking behavior for sandstone, coal and granite under uniaxial compression was analyzed to reveal likely mechanisms for failure modes. Lateral strain and AE count are effective parameters for early warning and failure time prediction of rocks via power-law singularity theory. [ABSTRACT FROM AUTHOR]

Understanding the mechanisms of crack propagation and failure behavior in rocks is fundamental for geotechnical engineering and mining applications. This study employs a coupled damage model based on the Smoothed Particle Hydrodynamics (SPH) method that integrates the Drucker–Prager and Grady–Kipp models. This mixed failure model is then implemented to simulate the crack propagation morphology and failure modes in uniaxial compression tests of flawed rock samples, and validated against multiple experimental observations. The numerical results exhibit good agreement with experimental observations from the literature in terms of the initiation and propagation of tensile and shear fractures, as well as the final failure morphology. Additionally, this work incorporates contact algorithms to simulate the loading plates, thereby better representing the actual experimental conditions encountered in uniaxial compression tests. Furthermore, a comprehensive parametric study is conducted to investigate the influence of key factors, such as pre-flaw geometry, cohesion, friction at the loading plate interface, and discretization parameters, on the simulated fracture processes and mechanical response. The outcomes indicate the proposed coupled damage model within the SPH framework can accurately capture complex fracture patterns and failure mechanisms in uniaxial compression of flawed rocks. This work demonstrates the capability of the SPH-based mixed-mode failure model to provide insights into rock fracture and failure mechanisms. Highlights: A coupled damage model integrating the Drucker–Prager and Grady–Kipp criteria within a smoothed particle hydrodynamics (SPH) framework is applied to simulate both shear and tensile failure modes in rocks firstly. The model is validated against more experimental observations, demonstrating the model's ability to reproduce the crack propagation and characteristic stress–strain behavior. This work presents a comprehensive parametric study investigating the influence of key factors, such as pre-flaw geometry, cohesion, friction at the loading plate interface, and discretization parameters, on the simulated fracture processes and mechanical response. These systematic investigations provide valuable insights into the governing mechanisms and highlight the importance of proper model calibration for accurate predictions. This work incorporates contact algorithms to simulate the loading plates, thereby better representing the actual experimental conditions encountered in uniaxial compression tests. The tensile wing cracks subjected to uniaxial compression, oriented vertically towards the top boundary of the specimen, are successfully captured. [ABSTRACT FROM AUTHOR]

Rockmass in deep mining is highly susceptible to large-scale collapses under high stress and blast-induced disturbances, leading to casualties and economic losses. To investigate the evolution characteristics of goaf instability and the types of seismic sources that induce instability, an experiment on goaf instability was designed under uniaxial compression conditions based on actual mining operations. The entire experimental process was monitored using digital image correlation analysis and acoustic emission monitoring. By calculating the digital speckle field on the surface of the rock specimen during the experiment, the evolution characteristics of the deformation and strain fields from the beginning of loading to complete failure were analyzed. The study explored the dynamic behavior of cracks from initiation to propagation and eventually inducing large-scale collapse. The results show that the instability process of the goaf begins with the formation of tensile cracks. As stress increases, shear cracks occur in the specimen, leading to macroscopic failure. Furthermore, based on the differences in overall microfracture types measured by RA-AF characteristic parameters during specimen failure, large amplitude acoustic emission events corresponding to the formation of dominant macroscopic cracks were selected, and the focal mechanisms of these events were inverted. The results indicate that shear failure sources are significantly more prevalent than tensile failure sources in acoustic emission events leading to goaf instability. These findings can provide useful guidance for the support design and the prevention and control of rockmass instability disasters. [ABSTRACT FROM AUTHOR]

With the increase in mining depth and intensity, dynamic disasters such as rockburst in mines are becoming more severe. Deep resource extraction is characterized by a high in-situ stress geological environment, closely associated with geological dynamic disasters. However, there is currently no quantitative analysis method for the correlation between the two. In this study, an elastic energy density calculation method is employed, considering the dissipative effect of the self-weight stress field on the tectonic stress field. The remaining energy, referred to as impact energy, is used to classify the risk of coal seam impact, providing a computational method for rapid assessment of impact risk before mining production. The proposed calculation method is compared with 22 mine impact engineering practices in the literature, showing accurate predictions for 21 mines. Since measuring in-situ stress and coal seam physical and mechanical properties is a preliminary work in coal seam extraction, the comprehensive analysis of these data holds significant research and practical value. [ABSTRACT FROM AUTHOR]

Deep underground galleries are used to access the deep biosphere in addition to mining and other engineering applications, such as geological disposal of radioactive waste. Fracture networks developed in the excavation damaged zone (EDZ) are concerned with accelerating mass transport, where microbial colonization might be possible due to the availability of space and nutrients. In this study, microbial biofilms at EDZ fractures were investigated by drilling from a 350-m-deep gallery and subsequent borehole logging at the Horonobe Underground Research Laboratory (URL). By using microscopic and spectroscopic techniques, the dense colonization of microbial cells was demonstrated at the surfaces of the EDZ fractures with high hydraulic conductivity. 16S rRNA gene sequence analysis revealed the dominance of gammaproteobacterial lineages, the cultivated members of which are aerobic methanotrophs. The near-complete genomes from Horonobe groundwater, affiliated with the methanotrophic lineages, were fully equipped with genes involved in aerobic methanotrophy. Although the mediation of aerobic methanotrophy remains to be demonstrated, microbial O2 production was supported by the presence of genes in the near-complete genomes, such as catalase and superoxide dismutase that produce O2 from reactive oxygen species and a nitric oxide reductase gene with the substitutions of amino acids in motifs. It is concluded that the EDZ fractures provide energetically favorable subsurface habitats for microorganisms. [ABSTRACT FROM AUTHOR]

The drilling rate index (DRI) of rocks is important for optimizing drilling operations, as it informs the choice of appropriate methods and equipment, ultimately improving the efficiency of rock excavation projects. This study presents a hybrid machine learning approach to predict the DRI of rocks accurately. By integrating grey wolf optimization with support vector machine (GWO-SVM), random forest (GWO-RF), and extreme gradient boosting (GWO-XGBoost) models, the aim was to enhance predictive accuracy. Among these, the GWO-XGBoost model exhibited superior predictive performance, achieving a coefficient of determination (R²) of 0.999, mean absolute error (MAE) of 0.00043, root mean square error (RMSE) of 1.98017, and severity index (SI) of 0.0350 during training. Testing results confirmed its accuracy with R² of 0.999, MAE of 0.00038, RMSE of 1.80790, and SI of 0.0312. Furthermore, the GWO-XGBoost model outperformed the other models in terms of precision, recall, f1-score, and multi-class confusion matrix results for each DRI class. The GWO-RF model also demonstrated high accuracy, ranking second, while the GWO-SVM model showed comparatively lower performance. This research aims to advance rock excavation practices by providing a highly accurate and reliable tool for DRI prediction. The results highlight the significant potential of the GWO-XGBoost model in improving DRI predictions, offering valuable intuitions and practical applications in the field. [ABSTRACT FROM AUTHOR]

In order to reveal the failure morphology and mine pressure behavior of overlying strata during shallow buried close multi-coal seam mining, this research takes the Shenmu Zhangjiamao mining area as the engineering background, the study of overlying rock movement and mine pressure distribution law in shallow and close coal seams was carried out. The results show that: with the gradual mining of 2−2 coal seam, the support stress in front and back of the working face increases first and then decreases, and the compaction strength of the collapsed overburden in the middle of the mined-out area increases gradually. With the mining of 2−3 coal seams, the displacement of the direct roof of the lower mined-out area and the rock layer of the upper compaction area increases gradually. With the increase of interlayer spacing, the peak stress in the concentrated stress area on both sides of the 2−3 coal seam decreases gradually. The compaction stress of overlying strata in the upper mined-out area decreases gradually, and the peak value of compaction stress in the middle of the lower goaf increases gradually. Through the measured results of the borehole stress sensor and separation instrument, the obvious influence range of the advance support pressure of the working face is about 40 m. The research results can provide practical experience for similar coal seam group mining in other mines, and can also be used to study the mining pressure behavior of inclined close distance multiple coal seams. [ABSTRACT FROM AUTHOR]

In the past five years, the number of articles related to ultrasonic mineral flotation has increased by about 50 per year, and the overall trend is on the rise. The most recent developments in ultrasonics for flotation process intensification are reviewed herein, including effects of ultrasound treatment on an aqueous slurry, improvement in flotation methods and technological processes, device development tracking, and application effects in mineral process engineering. At this point in time, there are pilot-scale flotation tests to evaluate the feasibility of ultrasonic pretreatment technology for industrial use to enhance residue flotation separation, and the results showed that the recovery rate of concentrate is increased by about 10%. Four aspects of ultrasonic flotation process improvement are summarized, namely, changing the ultrasonic parameters, the synergistic effect of ultrasound and reagents, the ultrasonic effect of particles with different-sized fractions, and application to new systems. In addition, the effect of ultrasonic flotation mechanisms is explored through a quadratic model and numerical simulation. The combination of ultrasonic flotation with other fields, such as magnetic fields, to enhance the separation efficiency and recovery of minerals is also a future trend. It is also proposed that ultrasonic flotation technology will be used with big data, industrial Internet of Things, and automatic control technology to achieve deep bundling, optimizing the flotation process by implementing remote monitoring and control of the flotation process. [ABSTRACT FROM AUTHOR]

Based on field geological surveys and laboratory rock physical and mechanical test data, the rock mass quality of the slope at Daxigou Iron Mine was evaluated, and the physical and mechanical parameters of the rock mass were determined. Using numerical simulation methods, stress, displacement, slip zones, and safety factors for the slope during different stages of open-pit mining were analyzed. The research results indicate that the safety factor of the slope decreases as the bench height increases. Under natural conditions, the safety factor in different excavation stages remains above 1. 8, indicating good slope stability. Rainfall significantly affects slope stability, and under saturated conditions, the final slope's safety factor decreases to 1. 36. However, this is still above the safety factor (1. 25-1. 20) stipulated in GB 51016-2014 Technical Specifications for Open-pit Mining Engineering in Non-coal Mines, indicating that the mine's slope design parameters are reasonable. The research results provide a reference for the design of subsequent safety facilities at the mine. [ABSTRACT FROM AUTHOR]

This study addresses the characteristics of rock masses in gold mine engineering, analyzing 7 key factors affecting rock mass stability:rock uniaxial compressive strength, RQD value, joint structural face conditions, joint structural face spacing, groundwater conditions, effect of joint structural face orientation on engineering, and on-situ stress value. These 7 indicators were adjusted to establish the rock mass quality M-RMR safety evaluation system. Using the M-RMR system, the engineering rock mass quality grades were classified for the Jiaojia Gold Mine-s directly managed mining area, Sizhuang mining area, and Wang-ershan mining area. Furthermore, a neural network knowledge base model was developed to correlate the underground rock mass quality at Jiaojia Gold Mine with its influencing factors, achieving intelligent grading of the rock mass quality for engineering purposes. To simplify the M-RMR indicator system for easier practical application, variable importance projection (VIP) was used to rank the information carried by the 7 indicators, allowing the removal of unimportant variables one by one. The simplified prediction model was built using partial least squares regression of single dependent variables (PLS1). This simplified model can accurately grade rock mass quality using fewer evaluation indicators, demonstrating practical application value. [ABSTRACT FROM AUTHOR]

This paper presents a laboratory testing rig designed to investigate the failure mechanisms and load transfer of rock masses under rock anchor loading. The study revealed that joint patterns significantly affect the strength and capacity of the rock mass, with existing design approaches based on apex angles of 90 ∘ or 60 ∘ found to be potentially overly conservative. Joint orientation and spacing should be included in the anchor design to obtain a more precise design criterion. In all the studied patterns, increasing the horizontal and vertical stress increased the block models' capacity, and load arching did not occur in the model with an unfavourable joint orientation. This study also revealed that the failure surface followed the joints in all tests and that the block model capacity was significantly higher than estimated with the design principle based on the weight of the overlying rock. The findings of this work have important implications for designing rock anchoring systems in mining and civil engineering demonstrate that joint orientation and block size significantly affect the rock mass capacity. This study confirms the need to consider the influence of in situ stresses on rock mass capacity when designing of rock anchors. Overall, this work guides the development of more precise design criteria for rock anchors, contributing to more efficient and effective rock engineering practices. Highlights: The models exhibited increase in horizontal stress upon application of a vertical anchor load to the blocks, indicative of load arching effects. The maximum vertical displacement in the blocks was in the normal direction to one of the joint sets under the influence of a vertical anchor load. The capacity of the block models was enhanced with an increase in both horizontal and vertical in situ stress. Crater-like failures were observed, with separation surfaces aligning with the joint set surfaces. Apex angles of the block patterns ranged from 90 to 140 ∘ ; symmetrical failures were observed in models with symmetrical jointing around the anchor. [ABSTRACT FROM AUTHOR]

Static crushing agent (SCA) offers advantages such as good safety, no harmful gases, and minimal vibration, making SCA ideal for rock crushing in mines or underground engineering. To scientifically implement the section expansion of mine roadway, the rock mechanical parameters, SCA expansion properties, and cracking behavior of surrounding rock were investigated using laboratory tests, numerical simulations, and field experiments. Results indicate that the smaller hole spacing of SCA improves the fracturing effect on rock mass, reduces the required fracture initiation stress and penetration stress, and the presence of a free surface aids in fracture development in the rock mass. Optimal borehole design parameters and spacing distributions of the SCA were determined, and corresponding construction techniques of roadway expansion were proposed. Field tests demonstrate that static crushing technology, under multi-row drilling conditions, is highly effective for rock roadway expansion projects. These findings provide valuable guidance for non-explosive expansion and other roof breaking treatment projects. [ABSTRACT FROM AUTHOR]

Gob-side entry retaining (GSER) technology has been widely used in underground coal mines. However, the applicable conditions of GSER technology in practical engineering still need further clarification to prevent the safety hazards and significant economic losses caused by its failure. In this study, 587 application cases of GSER in China from 2000 to 2024 were collected, and the relevant data, such as geological conditions and key technical parameters of GSER projects and their impact on engineering practices, were systematically analyzed. Considering the technical characteristics and the developing status of GSER technology, the current status of the application of GSER engineering in the mining areas of China was obtained, and then the applicable geological conditions and optimal technical parameters for the effective implementation of GSER technology were identified. Additionally, the existing technical challenges and further prospects of GSER technology were illustrated. This study provides a reference for reasonable applications and further research of GSER technology. [ABSTRACT FROM AUTHOR]

The deep integration of computer field and coal mining field is the only way to coal mine intellectualization. A variety of artificial intelligence tools have been applied in open-pit and shallow coal mines. However, with the geometric increase of coal demand, the contradiction between supply and demand is becoming more and more serious, and the exploitation of resources from shallow layer (> 600 m) has become an inevitable trend. Well then, as a new engineering scene, the harsh conditions of "three high and one disturbance" seriously threaten the safety of personnel. The superposition of complex mining environment makes the number of input factors increase sharply, which leads to the application of artificial intelligence in deep coal mine roadway engineering. The guidance is not mature, the construction of various databases is missing, and there are still some problems in universality and applicability. To this end, this paper starts with the introduction of the operating characteristics of various artificial intelligence tools, and conducts a comprehensive study of the relevant high-level articles published in top journals. It systematically sorts out the research progress that has successfully solved the five directions of rock mechanics strength, surrounding rock stability, rock-burst, roof fall risks and micro-seismic events. While objectively evaluating the comprehensive performance of different tools, it also expounds its own views on key research and results. Literature review shows that whether as a development tool or a comparative model, the application of ANN in the field of coal mining is more than 98%, and it performs extremely well in the direction of surrounding rock stability and roof fall risk, with an accuracy rate of more than 90%. As the most mature direction of AI tools application, rock mechanical strength has experienced the development process from "SVM → ANN → DL → XGBoost → RF". The dataset is from small samples (< 100) to big samples (> 1000), and the R2 of tree-based models can be stabilized at more than 95%. The research on rock-burst prediction mainly focuses on field factors and micro-seismic monitoring data. Whether it is a small sample or a large-scale data model, the accuracy of BN remains above 85%. The prediction and evaluation of micro-seismic events is a new direction in recent years. The image processing and application of CNN is extremely important. The signal recognition and classification accounts for more than 90%, and the research potential of source location needs to be further explored. In general, the nature of the rock itself is the first choice for almost all influencing factors. At the same time, the update iteration of monitoring methods (micro-seismic, ground sound, separation, deformation, etc.) expands the development of the database, making it possible to obtain the data due to threat to life and cost of equipment, which is very difficult to obtain before. In the process of parameter selection at the input end, the method of combining lithology conditions, geological environment and monitoring data will gradually become the first choice for research. Finally, in the follow-up work collation and on-the-spot investigation, it mainly focuses on the existing problems of deep coal mines, explores the application potential of artificial intelligence in deep coal mine roadway engineering, puts forward the possible research focus and challenging problems in the future, and gives its own opinions. [ABSTRACT FROM AUTHOR]

Background: Rock slope instability is a complex geotechnical issue that is affected by site-specific rock properties, geological structures, groundwater, and earthquake load conditions. Numerous studies acknowledge these aleatory uncertainties in slope stability assessment; however, understanding the rock behaviour could still be improved. Therefore, this paper aims to summarise the probability methods applied in rock slope stability analysis in mining and civil engineering and develop new probabilistic design and assessment methodologies for four methods, namely empirical/rock mass classifications techniques, kinematic analysis, limit equilibrium (LE), and numerical methods and introduces how to integrate all methods to determine the total probability of failure. The case studies have been conducted based on slopes from Indonesia, a seismically active country, utilising the proposed design methods. Results: Regarding the probabilistic empirical/rock mass classification (RMC) technique, this study has identified that seven of the ten most involved input parameters in RMC naturally exhibit aleatory uncertainty. Thus, the optimal way to present the output probability of RMC is as a confidence interval (CI) or total and conditional probability associated with each rock mass class. In probabilistic kinematic analysis, this study presents a systematic method to compute the probabilities of different types of failure alongside the total probability of occurrence (PtK). The probability of failure (PoF) for jointed generalized Hoek-Brown (GHB) numerical modelling was lower than that obtained through the probabilistic LE approach for a similar slope. However, the PoF of jointed GHB is higher than the LE approach when loaded with 0.1 and 0.15 earthquake coefficients. Conclusions: The variation of PoF across different failure criteria determines how epistemic uncertainty is apparent in the modelling process, while the aleatory uncertainty arises from input parameters. Furthermore, this study introduces the total probability of failure equation as a combination of kinematic and kinetic probabilities (limit equilibrium and numerical modelling). [ABSTRACT FROM AUTHOR]

Rockburst hazards occur sporadically after excavation of deep-buried hard rock tunnel. These failures in the surrounding rock masses are primarily induced by high ground stress, rendering conventional rock mass quality classification systems less applicable. This study discusses the limitations of existing rock mass quality classification systems when applied to deep-buried hard rock tunnels. A rockburst intensity tendency index, quantified through microseismic (MS) monitoring, is introduced and integrated into the RMR system, resulting in the development of an engineering rock mass quality classification system fordeepburied hard rock tunnels (DHRT-RMR). The development process involves: (i) selecting input parameters, including the rockburst intensity tendency index, and defining their weightings using the AHP; and (ii) establishing the DHRTRMR system based on the principles of the RMR system. The rockburst intensity tendency index, DHRT-RMR system, and RMR system are then applied to two test sites selected from a tunnel in southwest China. Results indicate that the standalone use of RMR or the rockburst intensity tendency index is limited in engineering rock mass classification for deep-buried hard rock tunnels. However, the DHRT-RMR system can accurately assesses rock mass qualities in such tunnels. [ABSTRACT FROM AUTHOR]

In conventional opencast mining, blasting plays a significant role in mining activity. Basically, blasting is done in mining activity to create fragmentation. However, the process of fragmentation through blasting results in various side effects. The most prominent side effects include flyrock, airblast, and ground vibration. Also, the desired fragmentation size varies depending on the mineral being extracted. So, the type and quantity of explosive used should be optimized, as they can increase the magnitude of side effects, such as flyrock, airblast, and ground vibrations. actors, including space, burden, stemming material type, and stemming column height also affect all the aforementioned negative impacts. In this article, a case study of Indian mines measures the unfriendly impacts of blasting in opencast mining. [ABSTRACT FROM AUTHOR]

The thick ore bodies in the Xianglushan tungsten mine have been irregularly mined, forming a super large, connected irregular goaf group and tall, isolated irregular pillars inside. At the same time, there is a production capacity task of recovering residual and dangerous ore bodies. This poses the potential for serious ground-pressure disasters, such as roof caving, pillar collapse, and large-scale goaf collapse during mining. Based on the actual needs of the site, we established a microseismic monitoring system. After analyzing the mining and filling processes and their relationships, and, combined with the distribution characteristics of microseismic multiple parameters, we constructed a ground-pressure disaster warning mode and mechanism. We analyzed the stability of the goaf, further formed a warning system, and achieved disaster warning. In response to the current situation of the difficulty of early warning of ground pressure in the Xianglushan tungsten mine, continuous on-site monitoring of existing goaves, point pillars, and strip pillars, as well as analysis of stress changes during dynamic mining and filling processes, we explored scientific and reasonable early warning mechanisms and models, understanding the relationship between the changes in microseismic parameters during dynamic mining and filling processes and ground pressure, studying and improving the reliability of underground microseismic monitoring and early warning, and achieved the internal connection between building early warning systems and the prevention of ground-pressure disasters. The results indicate that the mining and filling process of the ore body is the main factor in maintaining a stable and balanced distribution of underground ground pressure in mining engineering. Microseismic monitoring can invert the evolution of ground pressure and form a feedback system with ground-pressure warning, achieving mine safety management. [ABSTRACT FROM AUTHOR]

With the escalating demand for advanced and eco-friendly processing technologies in mining engineering, the potential applications of microwave heating technology in the treatment of cement tailings backfill (CTB) are expanding significantly. This research comprehensively investigates the mechanisms through which microwave irradiation duration and power influence the mechanical properties of CTB with varying concentrations and cement-to-sand ratios. The aim is to reveal the influencing patterns through experimental methods, providing scientific evidence for optimizing CTB treatment processes. This paper conducted microwave heating tests, uniaxial compression tests, and SEM-EDS tests on CTB. The research results indicate that heating time and power significantly enhance the early strength of CTB, with a more pronounced effect on CTB with higher concentrations and higher cement–sand ratios. When the heating time is 7 min and the heating power is 340 W, the cement hydration reaction is maximally promoted, thereby increasing the density and strength growth rate of CTB. However, excessively long heating time or overly high heating power may cause microcracks or thermal stress concentration within the CTB, adversely affecting the strength growth rate of CTB. Optimal thermal exposure duration and microwave power settings facilitate the activation of cementitious materials and the nucleation of calcium-silicate-hydrate (C-S-H) phases, thereby accelerating the compressive strength evolution of cemented tailings backfill (CTB). The outcomes of this research offer valuable insights into the deployment of microwave heating methodologies in underground mine backfilling, which are pivotal for augmenting the economic viability and environmental sustainability of mining operations. [ABSTRACT FROM AUTHOR]

In the field of deep mining engineering, high-pressure water jets progress toward larger diameters and higher velocities to enhance their impact performance. Understanding the decay characteristics as well as their implications remains challenging. In this article, the jet spread coefficients (k and c) within the empirical model of jet diffusion are determined by series of lab experiments, while simulations using the Eulerian method are conducted by implementing the modified diffusion model as a subroutine. The effects of spread coefficient, jet velocity, and nozzle diameter on the degree of jet decay are studied. The results show that the jet spread coefficient increases logarithmically with increasing jet velocity. With the increase in nozzle diameter, the growth of spread coefficient k of the jet gradually decreases. Increasing the nozzle diameter and spread coefficient k can effectively reduce the decay degree of jet axial velocity and water volume fraction. Notably, although the increase in jet velocity does not impact the decay of axial velocity, it exacerbates the decay of water volume fraction. Similarly, the increase in spread coefficient c has no effect on the reduction of water volume fraction, but it intensifies the decay of jet axial velocity. The combined effects of increased jet velocity and jet spread coefficient weaken the degree of jet decay. The research presents a comprehensive and innovative study of jet diffusion and attenuation phenomena. These insights not only expand the application of jet diffusion models but also provide theoretical support for understanding and optimizing the application of jets. [ABSTRACT FROM AUTHOR]

Three-dimensional printing (3DP) technology has shown great potential in rock mechanics and mining engineering due to its ability to create complex and customized objects with high precision and accuracy. At present, an emerging research focus is improving the mechanical properties of 3D-printed samples, which originally has low strength and stiffness, to match those of natural rocks. The objective of this study was to investigate the effectiveness of different post-treatments on the strength enhancement of 3D-printed gypsum samples. To achieve this goal, 3D-printed gypsum samples were subjected to different post-treatments including dipped infiltration treatment and vacuum infiltration treatment using different infiltrants: water, saltwater, ColorBond, and StrengthMax. Subsequently, each sample was subjected to ultrasonic wave velocity testing and uniaxial compression experiments to characterize their mechanical properties, CT scans to investigate their microstructural characteristics. Additionally, X-ray Diffraction (XRD) and Scanning Electron Microscope (SEM) tests were conducted to explore the underlying reasons for changes in macroscopic strength. Finally, the physical characteristics and mechanical properties of untreated and post-processed 3D-printed gypsum samples were compared with natural rocks. The results showed that the strength of samples treated with water and saltwater was much lower than that of those treated with ColorBond and StrengthMax, while the porosity was the opposite. In water-treated and saltwater-treated samples, water or saltwater treatment can alter particle characteristics, but weak adhesive bonding and numerous pores result in low mechanical strength. Samples treated with Colorbond or StrengthMax exhibit improved strength due to effective gap filling and cohesive structure formation, with StrengthMax-treated samples showing higher strength despite having more pores than Colorbond-treated ones. Moreover, the physical and mechanical properties of these treated samples matched a wider range of natural rock types compared to the untreated samples. Highlights: This study investigates the impact of different post-treatments and infiltrants on the physical and mechanical properties of 3D-printed gypsum samples. A novel method is proposed in this study to quantitatively evaluate the degree of infiltration by comparing the changes in porosity before and after vacuum infiltration of 3D-printed samples based on 2D CT images. The study provides an in-depth analysis of the mechanisms responsible for the macroscopic strength enhancement in 3D-printed samples after vacuum infiltration treatment. Vacuum infiltration treatment using StrengthMax significantly improves the physical and mechanical properties of 3D-printed gypsum rocks, allowing them to replicate a wider variety of natural rocks compared to untreated samples. [ABSTRACT FROM AUTHOR]

Borosins are a class of ribosomally synthesized and post-translationally modified peptides (RiPPs) with α-N-methylated backbones. Although the first mature compound of borosin was reported in 1997, the biosynthetic pathway was elucidated 20 years later. Until this work, borosins have been able to be categorized into 11 types based on the features of their protein structure and core peptides. Type III borosins were reported only in fungi initially. In order to explore the sources and potential of type III borosins, a precise genome mining work of type III borosins was conducted in bacteria and KchMA's self-methylation activity was validated by biochemical experiment. Furthermore, a commercial protease and AI-assisted rational design was employed to engineer KchMA for the capacity to produce various N-methylated peptides. Our work demonstrates that type III borosins are abundant not only in eukaryotes but also in bacteria and have immense potential as a tool for synthetic biology. [ABSTRACT FROM AUTHOR]

As mining engineering progresses into the deep excavation phase, the intensification of high pressure, high temperature, strong disturbances, and complex geological conditions becomes increasingly prominent. Researchers perform stability analysis on the excavation area to reduce potential safety hazards during the extraction process. Developing a detailed numerical calculation model that accurately reflects the true geological structure is essential for numerical simulation analysis in mining engineering. Based on the excellent 3D geological modeling capabilities of 3D Mine software, this paper introduces a new 3D geological and numerical unified modeling method (3DMine-Rhino-HyperMesh) involving multi-software coupling and details the specific steps and concepts of this modeling approach. Subsequently, using a certain open-pit mine in Panzhihua as a backdrop, a detailed geological and numerical unified model is established, reflecting the true geological structure of the mining area, and the potential failure mechanisms of the mine slope are analyzed. The results indicate that the modeling method aligns well with the actual geological conditions, enhancing the grid quality of the numerical model and offering a new modeling approach for simulating and analyzing large complex geological entities in mining operations. [ABSTRACT FROM AUTHOR]

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This action research study examines how meaningful choice design affects the overall meaningful learning experience of a virtual reality educational serious game. An intervention was developed to teach hazard detection in mines and was tested by mining engineering postgraduate students at a tertiary institution. Qualitative findings suggest that participants felt that the application of meaningful choice design improved the overall learning experience. This design approach empowered players to tailor their experiences based on their strengths and weaknesses, enabling them to establish a personalized flow and pace to master the content. Moreover, participants expressed that the inclusion of meaningful choice design enriched their serious game experience and, consequently, enhanced their learning outcomes. Future research on serious games should focus on exploring replayability, quantifying the impact of positive game experiences on learning, and implementing various game design principles in educational serious games. This study advances game-based education by emphasizing the benefits of using game design techniques and positive play experiences for learning. [ABSTRACT FROM AUTHOR]

The influence of water content and dip angle conditions on the pre peak energy accumulation characteristics of coal rock assemblages and their mechanism of action are crucial for studying the stability of high dip angle coal seams. The results indicate that water content changes the peak strength turning point. The accumulated energy before the peak gradually decreases from 0° to 60° and increases at 60° to 90°. As the inclination angle of the interface increases, the pre peak energy accumulation decreases. As the water content increases, the proportion of coal components gradually increases, while the proportion of rock components gradually decreases, and the energy accumulated before the peak of coal components is greater than that of rock components. The energy reduction rate gradually increases from 0° to 60° and decreases from 60° to 90°. When the inclination angle of the interface is 0° ∼ 30°, 30° ∼ 60°, and 90°, the main mechanism affecting its stability is the combined effect of water weakening, water weakening, and interface slip, as well as the uneven deformation of the coal rock interface. [ABSTRACT FROM AUTHOR]

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Layered rocks are widely distributed in mining and underground engineering. The evolution processes, such as crack initiation, development and penetration, inevitably occur due to stress changes. This study carried out an experiment and numerical simulation to explore the correspondence between crack distribution and bedding dip, and to reveal the mechanical mechanism of layered rock fracturing. The results show that the layered rock specimens with different bedding dips obtained different stress combinations under the same uniaxial compression conditions. There are a total of five types of stress combinations, including pure compression type, compression shear type, pure shear type, tension shear type, and pure tension type. The Mohr circle is effective in characterizing the relationship between the stress combinations and failure modes. The failure mode of layered rocks in the range of 0° to 150° is presented the variation features of "tensile failure → compression-shear failure → shear failure → tensile shear failure → tensile failure". Furthermore, the combined distributions of dominant and secondary cracks are summarized into the penetrating mode, the exfoliation mode, the feather crack mode, and the associated mode in high-dip of layered marbles. This paper provides research ideas for stability monitoring and crack tracking of layered rock mass engineering. [ABSTRACT FROM AUTHOR]

The phenomenon of peripheral rock instability is more common in crushed bedrock roadways, and the fundamental reason for this lies in the significantly different characteristics of its peripheral rock stress field. Taking the newly dug belt inclined shaft of PingDingShan TianAn Coal Co., Ltd. No. 6 Mine as the engineering background, a mechanical model of a broken perimeter rock roadway was established by using classical rock mechanics theory. Stress distribution around the roadway of the broken perimeter rock medium was systematically analyzed, and radial and tangential stress formulas of the broken perimeter rock were deduced. Through the formula calculation, it was deduced that there was a stress drop in the intact surrounding rock outside the disturbed zone, and the radial stress of the intact surrounding rock in its deep part was relatively increased, while the tangential stress was relatively decreased. The existence of crushed surrounding rock increased the minimum principal stress and decreased the maximum principal stress of the unfractured surrounding rock, which proves that a well-maintained disturbed zone can play a lining role. Thus, a "U-shaped steel + inverted arch + bottom arch linkage beam + floor bolt compensation" support program was proposed. This joint support program easily forms a closed support structure, which is more effective in controlling the deformation of tunnel perimeter rock. The support structure can effectively resist the deformation of the surrounding rock and enhance bottom drum resistance. Through numerical simulation, it was concluded that the horizontal displacement of the two gangs was reduced by 70%, and the displacement of the top and bottom plates was reduced by 77% after optimization of the support, which effectively controlled the stability of the broken surrounding rock. [ABSTRACT FROM AUTHOR]

Geo-engineering problems are known for their complexity and high uncertainty levels, requiring precise definitions, past experiences, logical reasoning, mathematical analysis, and practical insight to address them effectively. Soft Computing (SC) methods have gained popularity in engineering disciplines such as mining and civil engineering due to computer hardware and machine learning advancements. Unlike traditional hard computing approaches, SC models use soft values and fuzzy sets to navigate uncertain environments. This study focuses on the application of SC methods to predict backbreak, a common issue in blasting operations within mining and civil projects. Backbreak, which refers to the unintended fracturing of rock beyond the desired blast perimeter, can significantly impact project timelines and costs. This study aims to explore how SC methods can be effectively employed to anticipate and mitigate the undesirable consequences of blasting operations, specifically focusing on backbreak prediction. The research explores the complexities of backbreak prediction and highlights the potential benefits of utilizing SC methods to address this challenging issue in geo-engineering projects. [ABSTRACT FROM AUTHOR]

The isolated island face determination is an important basis for coal mine safety supervision. In order to accurately determine the island attribute of the working face, a method for determining the island attribute of working face under a typical conditions is proposed based on the coal column size effect analysis. Combined with a mine engineering conditions, the size effect of the coal column in the west and north wing of the 305 working face was analyzed by theoretical analysis and engineering analogy. The results showed that: the coal column bodies of the west wing and north wing of the 305 working face did not cause large-scale serious damage of the coal rock mass due to excessive stress concentration. The leading support pressure range of the 305 working face was less than 120 m, which was significantly smaller than the width of the coal column in the north wing. The width of the extreme balance zone of the lateral support pressure of the 305 working face is 52.3 m. The coal column body in the west wing of the 305 working face is wider than the sum of the two extreme balance zones. The west and north wings of the 305 working face are not gob areas. The 305 working face is not an island working face.

This is an article in the field of mining engineering. The development of aluminum industry is subject to decisive factors such as bauxite resources. As a large aluminum industry country in the world, after nearly two decades of rapid development, domestic bauxite resources are becoming increasingly scarce, and the contradiction between ore supply is becoming increasingly prominent. How to ensure the sustainable supply of China's bauxite resource demand and ensure the sustainable and high-quality development of China's aluminum industry is an urgent problem to be solved. The author believes that in the environment of establishing and improving the economic system of green and low-carbon circular development and promoting high-quality development, in addition to continuously increasing the development and utilization of foreign bauxite resources, we can also strengthen the comprehensive utilization of domestic low-grade bauxite resources, restrict the export of primary aluminum products measures such as transnational transfer of aluminum production capacity and promoting small equity and multi-point investment in overseas aluminum industry, and improve the guarantee ability of sustainable supply of bauxite resources in China.

This is an article in the field of mining engineering. Under the background of "double carbon" and "ballast stone" of refractory gold ore resources, pre-oxidation is an effective pretreatment method for efficient gold extraction from refractory gold ores. Destroying the finely impregnated gold inclusions, and eliminating or avoiding the passivation, robbing or secondary wrapping of gold by harmful substances, are the key and bottleneck problems to determine the gold recovery rate in refractory gold ores. Understanding the phase transformation and reconstruction evolution of gold-bearing minerals during pre-oxidation process is critical for inclusions destruction directly and gold leaching. In this article, the typical characteristics of refractory gold ores and existing pre-oxidation techniques were outlined, and the research advances in phase transformation and reconstruction of gold-bearing inclusions in roasting oxidation, hot-press oxidation, biological oxidation, chemical oxidation and other pre-oxidation processes were summarized. The result shows that the gold-bearing sulfides are mainly transformed into Fe oxides (or As oxides) and sulfate (or arsenate) by pre-oxidation. However, due to the coupling effect of multiple factors such as oxidation temperature, atmosphere or oxygen concentration, pH value, redox potential, Bacterial characteristics, etc., sulfides may also be converted into elemental sulfur, sulfur oxide, thiosulfate, jarosite and scorodite. In addition, jarosite, iron oxide and calcium sulfate are the main solid matters leading to the secondary package of gold. Pre-oxidation process and microscopic mechanisms, such as neutral thermobaric oxidation with low temperature and pressure, bacteria domestication with thermophilic, alkalophilic and arsenic-resistant properties, process enhancement of bacterial oxidation under multi-factor coupling, green and efficient oxidant screening, and chemical oxidation based on multi-field coupling, etc., still need to be deeply researched. The coupling relationship and regulation among ore characteristics, process reaction of pre-oxidation, phase transformation and reconstruction of gold-bearing materials and gold recovery rate are the research hotspots and difficulties in the green and efficient pre-oxidation field for refractory gold ores in the future.

This is an article in the field of mining engineering. Magnesite in China is rich and good in quality. Its mineral quantity and grade rank the first in the world. It is widely used as the raw material for the production of magnesium oxide in industry. The change of microstructure of magnesite during calcination is the key to performance the properties of magnesia products. Taking this as the starting point, the technical progress of preparing high-performance magnesia products from magnesite is summarized firstly. Then, according to the restrictive factors of industry development, this article analyzes the future development trend of this field briefly.

Abstract The drilling rate index (DRI) of rocks is important for optimizing drilling operations, as it informs the choice of appropriate methods and equipment, ultimately improving the efficiency of rock excavation projects. This study presents a hybrid machine learning approach to predict the DRI of rocks accurately. By integrating grey wolf optimization with support vector machine (GWO-SVM), random forest (GWO-RF), and extreme gradient boosting (GWO-XGBoost) models, the aim was to enhance predictive accuracy. Among these, the GWO-XGBoost model exhibited superior predictive performance, achieving a coefficient of determination (R²) of 0.999, mean absolute error (MAE) of 0.00043, root mean square error (RMSE) of 1.98017, and severity index (SI) of 0.0350 during training. Testing results confirmed its accuracy with R² of 0.999, MAE of 0.00038, RMSE of 1.80790, and SI of 0.0312. Furthermore, the GWO-XGBoost model outperformed the other models in terms of precision, recall, f1-score, and multi-class confusion matrix results for each DRI class. The GWO-RF model also demonstrated high accuracy, ranking second, while the GWO-SVM model showed comparatively lower performance. This research aims to advance rock excavation practices by providing a highly accurate and reliable tool for DRI prediction. The results highlight the significant potential of the GWO-XGBoost model in improving DRI predictions, offering valuable intuitions and practical applications in the field.

Currently used machine diagnostic systems are based on very modern solutions based on the acquisition and recording of their operating parameters in real time. Increasingly available and high-tech sensor systems mean that the number of recorded parameters is increasing and their quality is improving. These data are mainly used to assess the technical condition of machines and the processes they perform. In mining, these data can also be used to assess and, at a later stage, improve the safety of the underground mining process. Referring to this issue, the paper presents examples of the use of diagnostic systems for powered roof supports and longwall shearers to assess the safety status of the underground hard coal mining process. In the case of the wall support, the focus was on measuring the pressures in the stands of its individual sections. Temporary changes in the values of these pressures constitute a valuable source of information regarding the interaction of the support with the rock mass. In particular, this concerns the identification of the effects of the informational impact of the rock mass on the longwall excavation protected by the support. The research results presented in the paper, especially in the case of very dangerous dynamic impacts, indicate the possibility of both diagnosing the operating condition of the section and identifying symptoms of exposure to such events. This undoubtedly significantly expands the possibilities of using the measured pressures. Diagnostic signals from a longwall shearer are also widely used. The current intensities drawn by its motors while cutting the rock mass, as well as the advance speed and its position in the wall make it possible to analyze these parameters and their changes before, during and after the occurrence of various types of events. These data enable the assessment of the effects of the rock mass on its operational efficiency and safety status. It also enables the identification of symptoms that precede the occurrence of such events. The presented examples indicate the need for a broader and more holistic approach to the use of diagnostic parameters of mining machines. In particular, this concerns the study of the cooperation between the support and the rock mass and its influence on the efficiency and safety of the rock mass mining process. The subject matter addressed relates to very important and current issues, and the developed methodology and obtained results should be applied in practice as soon as possible. [ABSTRACT FROM AUTHOR]

This is an article in the field of mining engineering. The deep sand gravel type pore brine in Qaidam Basin belongs to the unsaturated chloride type brine with high calcium, high sodium and low potassium. 480 kg of gravel-type pore brine at 1000～2000 meters underground in Dalangtan mining area was selected for the test, and evaporated and crysta-llized in the natural state in summer. The distribution law of ions in the solid and liquid phases, the salt crystallization law and crystal morphology were analyzed, and the main precipitation characteristics of potassium were studied. The results show when evaporating in the outdoor natural state, the salt precipitation process is mainly divided into four stages: halite→carnallite→bischofite→tachyhydrite. The salt evolution law in the halite stage conforms to the phase diagram of Na+, K+, Mg2+//Cl-—H2O at 25 ℃, and that in carnallite and bischofite stages conforms to the phase diagram of K+, Ca2+, Mg2+//Cl-—H2O system at 25 ℃. There is a separate precipitation stage of potassium, at which potassium is mainly precipitated in the form of carnallite, and the recovery rate of potassium is 85.76%. The K+content in the potassium mixed salt can reach 9.27%, which is a high quality raw material for the production of potassium fertilizer. Calcium precipitates after the brucite stage. The experimental results can provide references for the development and utilization of this type of brine.

This is an article in the field of mining engineering. The Southern Xizang is one of the main distribution areas of high temperature geothermal zones in China with rich geothermal resources. The chemical analysis and test results of the geothermal water show that the lithium content in the geothermal water of the high temperature geothermal zone in Southern Xizang can reach 34.51 mg/L, and the relative abundance of geothermal lithium is obviously better than that of the world's typical plateau Salt Lake brines, such as Clayton Valley in the Western Plateau of North America and Uyuni in the Andes Plateau of South America. The lithium magnesium ratio is mostly less than 3, which is conducive to lithium extraction from brine. The areas with high lithium content in the geothermal water of the high temperature geothermal zones in Southern Xizang are all distributed in the the Yarlung Zangbo River suture zone and the areas to the south, consistent with the distribution range of lithium rich rocks. At the same time, the Yarlung Zangbo River suture zone and its south area have more Cl-Na geothermal water than the north, and the south has higher TDS and longer circulation path. Based on the stable isotopic composition of hydrogen and oxygen in geothermal water and the provenance of lithium in the surrounding lithium-rich Salt Lake brine, it is inferred that the main sources of lithium in the geothermal water are leaching of lithium-rich rocks by geothermal water and lithium-rich magmatic hydrothermal solutions formed during magmatic differentiation.

This is an article in the field of mining engineering. This article analyzes the present situation of molybdenum resource exploitation and utilization in China, and predicts the future demand formolybdenum resource in China. Molybdenum is a strategic mineral resource in China, widely used in the field of the steel, and in the strategic emerging industries and high-tech fields of broad prospects for development. The present situation of molybdenum resource exploitation and utilization in China is analyzed from the aspects of molybdenum resource reserves, production, consumption, import and export trade, secondary recovery, etc., and the future demand of molybdenum resource in China is forecasted by department analysis method. The conclusion is that molybdenum resources are abundant in China, but the resource advantage is gradually weakening. The consumption structure of molybdenum resources needs to be optimized in China, the import and export trade is more concentrated, and the secondary recovery is relatively backward. The department forecast method predicts that China′s molybdenum resource demand in 2025, 2030 and 2035 will be 99 thousand t, 83 thousand t and 69 thousand t respectively. Therefore, molybdenum resource reserve system is proposed to ensure orderly development of resources. By increasing investment in scientific and technological research, the international market of molybdenum products will be expanded. A good job in the global molybdenum resource layout will be done to ensure the future of China′s countermeasures and suggestions, and provide reference for the sustainable development of molybdenum resource industry in China.

This is an article in the field of mining engineering. In this article, SEM-EDS, XRD, FT-IR, laser particle size analysis and other means were used to characterize the mechanical activation of boron and magnesium ore powder. The results show that the crystal structure of boraxite changes at the action of mechanical force from the regular and orderly crystal structure to the disorder of the amorphous structure. The particle size distribution of the ore powder is greatly affected by the mechanical force. At the experimental conditions of 200 r/min speed of the ball mill and the ratio of ball to material of 10∶1, the optimal activation time is 6 h, when the particle size of 90% of the ore powder is less than 21.5 μm. The activity of ascharite is related to the number of active bonds after activation. In a certain activation time, the activity of ascharite increases with increasing activation time, but the agglomeration of mineral powder particles at the action of van der Waals force for a long activation time leads to a decrease in activity. The mechanical activation pretreatment can reduce the dependence on sulfuric acid concentration and temperature in the leaching reaction of ascharite, and significantly improve the leaching rate of elements in ascharite. The experiments show that the leaching rate of ascharite after activation for 6 h is 50% higher than that of the raw ascharite under the condition of reaction temperature 25 ℃ and sulfuric acid concentration 1.48 mol/L. And amorphous SiO2 can be prepared at friendly conditions. The apparent activation energy decreases from 23.54 kJ/mol to 9.41 kJ/mol after activation. The diffusion of the solid product layer during the leaching process is the limiting link which affects the reaction of ascharite with sulfuric acid.

This is an article in the field of mining engineering. The diatomite was modified with sodium dodecyl sulfonate and ferroferric oxide, and the influence of external factors on the adsorption effect was analyzed. And the experiment of the phase composition change and the microstructure change after the modified diatomite adsorbs heavy metal ions was carried out. The results show that when the modified diatomite content is 4 g/L, the adsorption time is 40 min, the temperature is set to 30 ℃, the pH value is set to 5, and the initial concentration is set to 200 mg/L, the adsorption of the modified diatomite is relatively good. The fitting degree of the Freundlich model to the test curve is above 0.90, and the fitting degree of the Langmuir model to the test curve is below 0.9, which shows that the Freundlich isotherm adsorption model is more suitable for the change law of the adsorption of heavy metal lead ions on modified diatomite. There is no significant difference in the characteristic diffraction peaks of the XRD pattern before and after the adsorption of lead ions on the modified diatomite. Only the peak intensity of the diffraction peak is reduced. However, the other mineral components inside the modified diatomite remain unchanged and the structure does not change significantly. This also shows that modified diatomaceous earth can effectively adsorb lead ions in sewage. However, the adsorption process is basically physical adsorption.

This is an article in the field of mining engineering. In view of the concentration and enrichment of lithium ions in old halide in Qerhan Salt Lake, the expansion experiment of the multi-stage precision control process of old halide enrichment was completed by means of evaporation crystallization and step separation. The enrichment law of lithium and boron during evaporation was studied. The concentration of lithium ions reached more than 1 g/L, and high quality hydrochloromagnite was obtained. The material balance of the evaporation process of the salt pan was carried out, and the actual halogen yield and lithium yield of each phase of salt extraction were obtained, as well as the production capacity of the sun salt pan and the area distribution ratio of each level of the salt pan, which can provide reliable data support for the comprehensive development and utilization of potassium old brine extraction in Qerhan Salt Lake in the future.

This is an article in the field of mining engineering. As an important battery raw material in the field of new energy, the global demand for lithium is accelerating. For a long time, China has needed to import a large amount of lithium raw materials, and there is still expected to be a significant demand gap in the future. Unconventional brine sources such as geothermal brine, oil and gas field brine, and desalination wastewater in seawater containing contain considerable lithium resources and may become an effective supplement to conventional lithium resources. As a green and sustainable method for extracting lithium resources, the development of unconventional brine-type lithium resources faces significant opportunities. The discovery of abundant unconventional brine-type lithium resources in Sichuan, Xizang, Yunnan and other places in China will be of great help to solve the shortage of lithium raw material supply in China. By summarizing the current status and progress of unconventional brine-type lithium resource development and its key technologies both domestically and internationally, this article provides a reference for the development of unconventional brine-type lithium resources in China.