The Guanzhuang gold ore field, located in northeastern Hunan Province, is distinguished by its extensively developed ductile shear zones. This study aims to elucidate the structural development mechanisms within this region by employing kinematic vorticity parameters of the ductile shear zones to investigate the characteristics of regional metallogenic structures and to examine the relationship between structural mechanisms and vein development. Field investigations were conducted to assess the structural features of ductile shear zones within the Jinhong and Jinxing ore sections of the Hongyuan mining area, complemented by a detailed petrological microstructural analysis. The kinematic vorticity parameters were calculated using the Mohr’s circle method, resulting in W _k values of 0.707 and 0.758 for the Jinhong and Jinxing ore sections, respectively. These findings suggest that pure shear and simple shear are nearly equivalent in the Jinhong ore section. Furthermore, the ratios （ε/γ） of pure shear strain rate to simple shear strain rate were determined to be 0.509 and 0.449 for the Jinhong and Jinxing ore sections, respectively.The ε/γ ratios for the Zhengchong, Xiaojiashan, Jinhong, and Jinxing ore sections within the Guanzhuang gold ore field, arranged from west to east, are 0.842, 0.751, 0.509, and 0.449, respectively. All ε/γ ratios in the area are less than 1, indicating significant lateral tectonic movement within the Guanzhuang gold ore field. Furthermore, the ε/γ values exhibit a gradual decrease from west to east, suggesting an acceleration of simple shear rates in the same direction, which is indicative of nappe thrust tectonic movement. For the first time, a quantitative relationship has been established between kinematic vorticity parameters and vein variation coefficients. The variation coefficients （V _m） of orebody thickness for the four deposits demonstrate a positive correlation with the kinematic vorticity （W _k） values, with a fitted function expressed as W _k = 0.3146V _m + 0.3978. Conversely, the shear strain rate ratio （ε/γ） exhibits a negative correlation with gold mineralization, with a fitted function given by ε/γ=-0.5834V _c+1.4107. In conclusion, it is posited that this region corresponds to a hydrothermal deposit model typified by tectonic-magmatic-mineralization processes. The area experienced Caledonian hydrothermal activity, which facilitated the formation of gold deposits. The ductile shear tectonic movements have influenced the spatial distribution of gold ore bodies,it reveals ore bodies in any directions, but there are two sets of gold veins oriented in NWW and NNE directions.These orientations offer a principal framework for guiding prospecting activities.

The central segment of the Jiangnan orogenic belt is predominantly characterized by deposits of gold, antimony, and tungsten. Notably, the Tuobeishan antimony deposit, located in northwest Jiangxi, exhibits significant potential for mineralization and exploration. However, its genesis remains undetermined. This study aims to elucidate the genesis of the Tuobeishan antimony deposit by examining its geological characteristics through advanced analytical techniques, including scanning electron microscopy（SEM） and laser ablation inductively coupled plasma mass spectrometry（LA-ICP-MS）. The findings reveal that antimony within the deposit primarily occurs as stibnite（Sb₂S₃）, with lesser occurrences of tetrahedrite（Cu₁₂Sb₄S₁₃） and chalcopyrite（CuSbS₂）, with the paragenetic minerals including sulfides such as pyrite and sphalerite，as well as barite. The sulfide formation process is delineated into a diagenetic stage and a hydrothermal mineralization stage, the latter of which comprises three distinct phases: the quartz-stibnite stage, the quartz-calcite-stibnite stage, and the calcite stage. The precipitation of antimony ore is predominantly influenced by a reduction in fluid pH and temperature, which is accompanied by the concurrent precipitation of barite and calcite. The trace element characteristics of pyrite suggest that a portion of antimony（Sb） is incorporated into the pyrite lattice via a coupled substitution mechanism: （Tl⁺+Cu⁺+Ag⁺）+Sb³⁺→2Fe²⁺. The Tl content in pyrite is approximately an order of magnitude greater than that in stibnite, and there is a significant positive correlation between arsenic（As） and thallium（Tl） in the ore-forming fluids. Collectively, these findings imply that the ore-forming fluid of the Tuobeishan antimony deposit is primarily composed of cyclically evolved medium to low-temperature thermal fluids, with contributions from magmatic hydrothermal fluids.

The Songshubei gold deposit is situated in the northern segment of the Wulashan-Daqingshan metallogenic belt, along the northern margin of the North China Craton. The ore-hosting strata within this mining region are identified as the Archean Wulashan Group. Gold-bearing quartz veins, which constitute the orebodies, are hosted within both the Archean Wulashan Group and the Early Proterozoic mylonitized quartz diorite. The formation and spatial distribution of these orebodies are predominantly governed by the Houshihua-Songshubei ductile shear zone. The primary wall-rock alterations observed in the area include sericitization, chloritization, and potassic feldspathization. The principal sulfide minerals present are pyrite and chalcopyrite, categorizing the deposit as a sulfide-poor gold type. This study aimed to identify the primary gold-hosting minerals and characterize the occurrence of gold to inform exploration and resource extraction strategies, as well as to investigate the genesis of the deposit, including the sources of ore-forming materials and fluids. To achieve these objectives, the research integrated petrographic observations of quartz and sulfides from various mineralization stages with in-situ geochemical analyses. These analyses included electron probe microanalysis （EMPA）for major elements, laser ablation inductively coupled plasma mass spectrometry（LA-ICP-MS） for trace elements, and laser ablation multi-collector inductively coupled plasma mass spectrometry（LA-MC-ICP-MS） for sulfur isotopes on gold minerals and gold-hosting sulfides. The findings reveal that the Songshubei gold deposit is an orogenic-type gold deposit. Four distinct stages of mineralization were identified, with the third stage being the primary ore-forming period, occurring at a moderate crustal depth. Gold is predominantly present as native gold, primarily in the form of inclusions within pyrite. The gold grain sizes range from fine to very fine, with no visible gold observed thus far. The fineness of the gold varies from 856.26 to 944.95, with an average of 930.38. The gold-bearing pyrites are notably enriched in mesothermal chalcophile elements, including Au, Ag, Cu, and Pb. They are characterized by low Co/Ni ratios （ranging from 0.04 to 1.12） and highly variable Cu/Au ratios （ranging from 0.01 to 3 052.68）. Formation temperatures, as estimated using the selenium（Se）geothermometer, range from 365 ℃ to 583 ℃, suggesting precipitation from a mesothermal, reducing ore-forming fluid. In-situ sulfur isotope analyses of gold-hosting pyrite and coexisting chalcopyrite produced δ ³⁴S values between -2.91‰ and -1.19‰. These values fall within the typical range for mantle/magmatic sulfur and overlap with the sulfur isotope signature of the Archean Wulashan Group. This overlap indicates a mixed sulfur source, originating from both the metamorphosed Archean Wulashan Group and deep-seated mantle or magmatic sources. In conclusion, the Songshubei gold deposit is classified as an orogenic-type gold deposit, controlled by ductile shear zones. Its ore-forming process is primarily dominated by metamorphic fluids, with episodic incursions of deep-seated magmatic hydrothermal fluids. The ore-forming materials are mainly derived from a mixed source comprising the Archean Wulashan Group and mantle magma.

The Western Kunlun Orogenic Belt, situated along the northern margin of the Tibetan Plateau, represents one of China’s significant polymetallic metallogenic belts. The Kukaazi deposit, located in Yecheng County, Xinjiang, is a newly identified Pb-Zn-(Cu-W) polymetallic deposit within this belt, exhibiting considerable mineralization potential. However, due to its remote location and the paucity of fundamental geological research, the sources of ore-forming materials and the genetic classification of this deposit remain ambiguous, thereby limiting the comprehension of regional metallogenic patterns and hindering further exploration efforts. The deposit comprises three ore blocks: KⅠ, KⅡ, and KⅢ, with ore bodies manifesting as lenticular and stratoid forms within the marble, metasiliciclastic rocks, and contact zones of the Mesoproterozoic Changcheng System. Based on mineral paragenetic associations and cross-cutting relationships, the mineralization process is delineated into the dry skarn stage, the copper-iron sulfide stage, and the lead-zinc sulfide stage. This study undertook a comprehensive sulfur isotope analysis of metal sulfides from the KⅠ and KⅡ ore blocks, alongside a lead isotope analysis of metal sulfides, host rocks, and intrusive rocks, based on an in-depth characterization of the deposit’s geological features and mineralization stages. The objective was to trace the sources of ore-forming materials and elucidate the genesis of the deposit. The sulfur isotope analysis revealed that the δ ³⁴S values of metal sulfides range from 2.0‰ to 12.1‰, with a mean of 7.8‰, displaying a multimodal distribution. Notably, pyrrhotite from the copper-iron sulfide stage exhibited relatively low δ ³⁴S values(mean 3.5‰), akin to mantle-derived sulfur, whereas galena and sphalerite from the lead-zinc sulfide stage showed higher δ ³⁴S values (mean 10.3‰). This suggests that the early ore-forming fluid was predominantly magmatic hydrothermal in origin, with an increasing contribution from seawater over time. The lead isotope analysis indicated that the lead isotope compositions of metal sulfides were relatively homogeneous, with ²⁰⁶Pb/²⁰⁴Pb, ²⁰⁷Pb/²⁰⁴Pb, and ²⁰⁸Pb/²⁰⁴Pb values ranging from 18.394 to 18.733, 15.591 to 15.782, and 38.125 to 38.743, respectively. The observed values exhibit similarity to those found in intrusive rocks, yet they differ significantly from those of the host rocks. This suggests that the ore-forming materials were derived from a combination of magmatic hydrothermal fluids associated with felsic intrusive magmas and the deep metamorphic crystalline basement. The μ values of metal sulfides range from 9.44 to 9.80(mean 9.54), ω values from 34.54 to 38.13(mean 35.68), and Th/U ratios from 3.53 to 3.77(mean 3.62), indicating a crust-mantle mixed origin with a predominance of crustal components. Through a comprehensive analysis of the deposit’s geological characteristics and sulfur-lead isotope data, this study concludes that the Kukaazi deposit represents a distal skarn-type Cu-Pb-Zn polymetallic deposit associated with submarine volcanic activity. This research contributes novel geochemical data pertinent to the genesis of polymetallic deposits in the Western Kunlun Orogenic Belt and provides critical insights for regional mineral exploration efforts.

The Mangyahedong region is situated within the Qimantage metallogenic sub-belt of the western East Kunlun orogenic belt, noted for its advantageous metallogenic conditions. In recent years, a diverse array of mineral resources, including gold, lead-zinc, iron, cobalt-nickel-copper, and tungsten, have been progressively identified within an area spanning 80 km², yielding significant prospecting outcomes. Nonetheless, the metallogenic types and characteristics of these deposits have not been comprehensively summarized. Utilizing exploration and research data, this study integrates the geological characteristics of the deposits and preliminarily identifies five metallogenic types: （1）Structurally controlled alteration-type gold deposits, which are governed by northwest-trending ductile-brittle faults and hosted in volcanic rocks of the Qimantage Group, classified as orogenic gold deposits. （2）The volcanogenic massive sulfide(VMS) type lead-zinc deposit is located at the interface between volcanic and clastic rock formations, characterized by laminated siliceous rocks and massive to stockwork ores. （3）The hydrothermal type cobalt-nickel-copper deposit is fault-controlled and represents the first identification of independent cobalt minerals, such as grimmite(NiCO₂S₄), suggesting a mesothermal to epithermal origin. （4）The skarn-type iron deposit is situated at the contact zone between intermediate-felsic intrusions and carbonate rocks. The hydrothermal quartz vein-type tungsten deposit is characterized by scheelite-bearing quartz veins. The mineralization exhibits temporal progression and spatial zoning. Within the Ordovician back-arc basin, the volcanic-sedimentary sequence of the Qimantage Group was established, with the volcanic formation enriched in gold, cobalt, and nickel serving as the source bed, and synsedimentary fault exhalation leading to the formation of the VMS-type lead-zinc protore. During the Early Devonian, collisional orogeny resulted in the formation of orogenic gold deposits. In the Late Triassic, magmatic activity led to the development of skarn-type iron deposits, hydrothermal quartz vein-type tungsten deposits, and hydrothermal-type cobalt-nickel deposits. In terms of spatial distribution, the mineral deposits are collectively influenced by the three formations of the Qimantage Group and northwest-trending faults. Specifically, the volcanic formation is associated with gold(Au) and cobalt-nickel(Co-Ni) deposits, the clastic formation is linked to lead-zinc(Pb-Zn) and tungsten(W) deposits, and the contact zone of the carbonate formation is related to iron (Fe) deposits. The northwest-trending faults serve as the primary structures for ore transportation and hosting. Results from geochemical surveys conducted at a scale of 1∶25 000 reveal high coefficients of variation for gold and tungsten. Three northwest-trending anomaly belts(Au-As-Sb, Pb-Zn-Ag, Co-Ni-Cu-Cr) are spatially aligned with ore-controlling faults and host strata, with anomaly characteristics in the southeastern segment comparable to those in the northwestern segment, where known deposits are present. Based on comprehensive data integration, two prospecting targets have been identified: the Hongweishan-Heishigou Au-Pb-Zn target(YC2) and the Heishigou Co-Ni target(YC1). The former exhibits medium- to large-scale potential for gold and lead-zinc, while the latter demonstrates medium-scale potential for cobalt-nickel. This study offers a significant reference for mineral exploration within the Qimantage metallogenic belt.

The Wulonggou gold orefield is situated in the central segment of the East Kunlun Orogenic Belt and is characterized by meso-epithermal magmatic hydrothermal deposits and tectonic altered rock-type gold deposits. The spatial distribution, scale, and morphology of all identified gold orebodies in this region are stringently regulated by fractured tectonic alteration zones. These fracture alteration zones act as favorable conduits for the migration of ore-forming fluids and serve as primary sites for gold precipitation and enrichment. In recent years, the shallow mineral resources within the mining area have been progressively exhausted, prompting a shift in exploration activities towards the middle and deeper levels. However, the extension patterns of deep ore-controlling structures remain ambiguous, and the accurate localization of concealed orebodies presents significant challenges, thereby hindering substantial prospecting advancements in this region. To systematically elucidate the developmental characteristics of deep ore-controlling structures and objectively assess the deep gold prospecting potential of the mining area, this study conducts comprehensive research utilizing previously collected systematic physical property test data of rocks and ores. The statistical analysis of physical properties highlights a significant resistivity contrast between the intact wall rocks located at the roof and floor of ore bodies and the rocks within the ore-hosting fractured alteration zones. These fractured alteration zones, characterized by well-developed fractures filled with conductive minerals and groundwater, typically exhibit low-resistivity electrical signatures. This results in distinct electrical boundaries when compared to the high-resistivity wall rocks. Such differentiation provides a crucial physical basis for tracing deep tectonic alteration zones through electromagnetic geophysical prospecting in the study area. By leveraging this electrical differentiation, the implementation of suitable geophysical detection technologies in the middle and deep mining areas can accurately delineate the deep extension, variation in occurrence, and spatial scale of gold-bearing fractured alteration zones. Consequently, this approach offers robust scientific support for the precise planning and optimization of deep drilling verification projects. In this study, the transient electromagnetic method (TEM) was employed to perform subsurface detection tests aimed at identifying concealed deep structures within the middle and deep sections of the Huanglonggou ore block at the Shenshuitan gold mine. Four geophysical survey profiles were systematically arranged underground in the Huanglonggou ore block to ensure comprehensive coverage. Analysis of the collected data reveals that various fractured tectonic alteration zones in the study area exhibit distinct and pronounced low-resistivity anomaly responses. By integrating multiple sources of information, including underground engineering logs, surface geological data, and rock-ore physical property characteristics, the spatial relationships and distribution patterns among faults, gold-bearing mineral enrichment zones, and low-resistivity electrical anomalies within the ore block have been preliminarily elucidated. Guided by the structural ore-controlling theory, verification boreholes were strategically positioned at favorable metallogenic sites where the orientation of fractured alteration zones transitions significantly from steep to gentle. Industrial gold orebodies were successfully identified within the low-resistivity anomaly targets delineated by transient electromagnetic method (TEM). The drilling results conclusively demonstrate the technical superiority of TEM in detecting and tracing deep-seated, concealed ore-controlling faults, confirming its effectiveness and practicality for deep gold exploration in the study area. The integrated research framework developed in this study, which combines underground TEM detection, joint geological interpretation, and drilling validation, provides detailed and reliable geological and geophysical data essential for subsequent mid- to deep-level mineral exploration in the Wulonggou gold orefield. Additionally, it offers practical guidance for the precise localization and quantitative prediction of concealed gold orebodies in regions characterized by well-developed mid- to deep-level alteration zones. This study also presents valuable technical insights and practical case studies for the deep exploration of similar high-altitude, tectonically altered rock-type gold deposits within the East Kunlun Orogenic Belt and other analogous regions globally.

Cu-Ni sulfide deposits represent critical strategic resources within the non-ferrous metal sector. However, the exploration of these deposits, particularly in deep and peripheral regions, is fraught with significant challenges due to complex overburden and concealed ore bodies. Traditional geophysical methods, when applied singularly, exhibit notable limitations in this context, such as pronounced anomaly multiplicity and reduced interpretative accuracy, thereby hindering detailed exploration efforts around the extensive Jinchuan Cu-Ni deposit. This study addresses the technical challenges associated with the unclear identification of concealed ultramafic ore-bearing rock masses and the ambiguous differentiation between ore and non-ore anomalies. The research focuses on the Yangjiadashan area, located in the southeastern periphery of the Jinchuan rock mass. By integrating regional geological conditions and rock physical properties, the study employs a combination of high-precision magnetic surveys, induced polarization (IP) mid-gradient measurements, and bilateral three-pole IP sounding for field exploration. This study introduces an innovative “screening+weighting” multi-parameter fusion method designed to integrate magnetic ΔT, apparent resistivity, and polarizability data. This approach effectively mitigates lithological and overburden interference, reduces data redundancy, and enhances the precision of delineating concealed ore targets. Drilling validation has revealed a continuous pyrite ore body with an apparent thickness of approximately 5 meters at a depth of 264 to 269 meters, exhibiting sulfur and iron contents ranging from 13.60% to 26.43% and 10.65% to 15.58%, respectively. These findings confirm the applicability of the integrated geophysical and multi-parameter fusion technology for deep prospecting in the peripheral area of the Jinchuan deposit. Furthermore, this research offers a valuable technical reference for the detailed exploration of concealed copper-nickel ore bodies in similar mining regions and supports subsequent deep resource exploration of the Jinchuan deposit.

The Yunnan Chang’an gold mine, a significant mining site within the polymetallic mineralization concentration zone of the Ailao Mountains-Honghe orogenic belt in southwestern China, is situated in the southern section of the Jinping anticlinal structure. This site is characterized by a unique geological setting, marked by highly intricate subsurface geological formations. The complex terrain and topography create a variety of spatial conditions conducive to the formation of subsurface adverse geological features and the occurrence and movement of groundwater. Throughout prolonged mining operations, the presence of underground adverse geological formations and water hazards at the Chang’an gold mine has become increasingly prominent. Traditional prevention and control strategies primarily depend on hydrogeological mapping and drilling. However, the drilling process is intricate, time-consuming, and limited to point-based detection, which poses challenges in covering the three-dimensional space ahead of the tunnel. This limitation introduces the risk of “missed judgments”, and drilling in high-pressure areas may also precipitate “borehole-collapse” water disaster incidents. Consequently, these methods no longer satisfy the precision and timeliness demands of contemporary mines for advanced water disaster warning systems. In light of these considerations, this study selects the Chang’an gold mine as a representative case study, concentrating on the implementation of underground geophysical exploration techniques for the identification of adverse geological formations and water-related hazards. The objective is to address the challenges associated with the advanced detection of complex structural metal mineral water hazards and unfavorable geological formations. Initially, the research undertakes a systematic analysis of the underground geological conditions and primary disaster types present at the Chang’an gold mine. By evaluating the suitability of various geophysical exploration methods, the seismic wave technique （TST） and the advanced water probing method utilizing multiple frequencies （CFC） were identified as the core integrated technologies. Subsequently, given the constrained working environment within the underground tunnels of metal mines, the TST-CFC collaborative observation system was optimized and designed. This involved specifying the parameters for the seismic source, electrode configuration, data acquisition process, and processing standards, ultimately developing a comprehensive technical framework encompassing “data collection - anomaly interpretation-risk warning.” The study focused on the 1 450 m return air drift of the Chang’an section, as well as the 1 350~1 300 m slope passage and the 1 350 m middle section flat passage, as the primary subjects for detection. Each project had a forecast distance of 100 meters, culminating in a total of 300 meters of tunnel being completed for advanced detection purposes. Through a combination of on-site data collection, indoor processing, and comprehensive analysis, various forecast results were generated, including geological offset maps, rock wave velocity distribution maps, and CFC offset maps. These results facilitated the precise identification of the location, scale, and water content characteristics of adverse geological formations. Specifically, the 1 450 m return air drift revealed one adverse geological formation, the 1 350~1 300 m slope passage identified two such formations, and the 1 350 m middle section flat passage detected three adverse geological formations. The analysis of water gushing risks across the three tunnels demonstrated a successive upward trend. The TST-CFC collaborative detection technology scheme developed in this study has proven to be precise and efficient in identifying adverse geological formations and water-related hazards in complex structural metal mines, thereby effectively addressing the limitations of traditional detection methods. The findings of this research not only offer a scientific foundation for the Chang’an gold mine to optimize underground construction strategies, enhance disaster prevention and control measures, and improve disaster warning capabilities, but also provide replicable and scalable detection technology references for metal mines with intricate structural characteristics in the southwest region and beyond.

The method of large-diameter deep-hole stage open stoping followed by backfilling demonstrates high efficiency in the extraction of thick and extensive ore bodies. However, the presence of a significant fault within the mining area can result in a coupling effect between the fault and mining-induced stress, potentially triggering fault activation. This activation leads to complex ground pressure behavior, complicating the accurate delineation of the fault’s influence range using traditional empirical methods and posing significant challenges to the stability control of the stope. To address this issue, this study utilizes the porphyry ore section of Shanxi Zijin Mining as a case study. A three-dimensional refined numerical model is developed, incorporating the orebody, F₄ fault, backfill, and surrounding rock. This model systematically examines the influence mechanism of the fault on stress evolution, displacement response, and plastic zone propagation throughout the entire mining process. Furthermore, the study proposes a quantitative method for defining the fault’s influence range. Utilizing the Barton rock mass quality Q-value classification and the Hoek-Brown criterion, the mechanical parameters of the orebody and surrounding rock were determined. The model employs the Mohr-Coulomb elastic-plastic constitutive law to simulate a two-level, interval mining sequence, facilitating a comparative analysis between two distinct stages: mining in fault-free areas and mining in fault-affected areas. By comparing the computational outcomes of models with and without the fault, the relative displacement growth rate method was introduced to quantitatively ascertain the influence distance of the F₄ fault. The findings indicate that during mining in fault-free areas, the maximum shear stress in the surrounding rock adjacent to the goaf reaches 67.35 MPa, with a maximum displacement of 19.26 cm. The plastic zone is predominantly characterized by shear failure, exhibiting a maximum yield volume of 135×10³ m³. The roof of the goaf is primarily subjected to tensile stress, while the tunnel sides display a partitioned failure pattern of tension and shear. Under the influence of the fault, the maximum shear stress escalates to 100.75 MPa, marking an increase of 49.6%. Concurrently, the maximum displacement ascends to 47.12 cm, and the maximum yield volume of the plastic zone expands to 226×10³ m³. Both shear and tensile failures are observed, leading to a significant enlargement of the plastic zone and pronounced asymmetric deformation in proximity to the fault. Through a comparative analysis of models with and without the fault, and utilizing the relative growth rate curve of displacement with a 100% change rate as a reference, the maximum influence distance of the F₄ fault is determined to be 28.5 m. Within this range, the deformation of the surrounding rock is substantially governed by the fault. In response to the fault-affected zone, systematic control measures are proposed, including the reinforcement of support structures, optimization of stope structural parameters, and enhancement of backfill strength within the fault-impacted area. The findings of this research offer a quantitative foundation and engineering strategy for the safe and efficient implementation of the stage open stoping with subsequent backfilling method under fault conditions.

As shallow mineral resources become increasingly exhausted, metal mining operations are progressively extending to greater depths. These deep mining environments are inherently complex and challenging, often characterized by high stress, elevated temperatures, significant osmotic pressure, a heigh tened risk of rock bursts, and considerable mining-induced disturbances. Particularly for fractured ore bodies situated beneath water bodies, buildings, and transportation routes—collectively termed as “three-under” conditions—mining operations are required to adhere to stringent ecological standards, including zero surface subsidence and the protection of river ecosystems. Consequently, ensuring safe and efficient mining under these conditions presents a significant challenge that demands urgent attention. In response to this issue, this study examines a deeply situated, steeply dipping, thick, and massive fractured ore body within a lead-zinc mine located in a scenic area of Nanjing. The research focuses on the selection of appropriate mining methods and the optimization of mining structure parameters.Initially, a comprehensive evaluation system incorporating 13 core indicators was developed to address multidimensional requirements such as mining technology, economics, safety, and environmental compatibility. The analytic hierarchy process （AHP） was employed to ascertain the weights of each indicator. This was integrated with a fuzzy mathematics-based comprehensive evaluation method to facilitate a scientific comparison among three preliminary schemes: the upward-seam layered stoping with backfilling method, the upward-seam horizontal layered pillar backfilling method, and the upward-seam backfilling method. The evaluation results reveal that the upward drift backfilling method emerged as the optimal mining scheme, attributed to its superior performance in operational safety, loss rate control, and minimal impact on the backfill body. Secondly, to validate and optimize the structural parameters of this scheme, the FLAC^3D numerical simulation software was employed to systematically analyze the stability of the mining face within the specified ranges of drift height （3.5~4.5 m） and width （3~6 m）. The results from both simulation and engineering applications indicate that at the maximum dimensions （4.5 m in height and 6 m in width）, the maximum tensile stress （4.67 MPa） and compressive stress （68.99 MPa） in the surrounding rock remain below the strength limits of the ore and rock. Furthermore, the maximum roof settlement （4.02 mm） and maximum floor heave （4.11 mm） are significantly below the permissible values stipulated by codes. The distribution of the plastic zone is sporadic, with no continuous failure zone observed, thereby demonstrating that the working face maintains an overall stable state. By implementing the optimized plan within the engineering practices at the -725 to -775 m levels, the actual production capacity of the mining area increased to 196.4 t/d, and the ore loss rate was significantly reduced from 27% to 5%. This was achieved while concurrently meeting the ecological protection objective of zero surface subsidence. Through the integration of the analytic hierarchy Process （AHP）-fuzzy comprehensive evaluation with FLAC^3D numerical simulation, this study developed a closed-loop technical system encompassing method selection, parameter optimization, and engineering validation. This approach not only effectively addressed the mining challenges associated with deep, fractured ore bodies under “three-under” conditions at this site but also established a replicable and scalable technical paradigm for safe, efficient, and environmentally sustainable mining under similar complex constraints.

At present, there are some problems in the process of gravity separation shaking table beneficiation, such as low efficiency and high cost of manual identification of ore belts, as well as large number of parameters and insufficient accuracy of existing segmentation models. This study addresses these challenges by developing a model that is both computationally efficient and highly accurate for the segmentation of scheelite zones under ultraviolet light, a condition that enhances the natural fluorescence of the target mineral. Central to this research is a significantly enhanced DeepLabV3+ model, which integrates several critical architectural modifications. Initially, the computationally intensive Xception backbone was substituted with the more efficient MobileNetV3 network, which was further enhanced by integrating an efficient channel attention module. This modification aimed to reduce the parameter count while enhancing feature representation. Subsequently, the encoder’s atrous spatial pyramid pooling module was restructured into a DenseASPP configuration. This redesign incorporated additional atrous convolutional branches to establish a more continuous range of receptive fields, thereby facilitating superior multi-scale feature extraction from mineral bands of varying widths. Furthermore, the decoder was augmented with a convolutional block attention module to highlight discriminative features and suppress noise, complemented by deformable convolutions to accommodate the irregular shapes and boundaries of the mineral zones. The model was trained and evaluated on a custom-developed dataset of ultraviolet-lit scheelite images, which was expanded using data augmentation techniques. A series of ablation studies confirmed the contribution of each proposed enhancement. In comparative experiments, the final model exhibited superior performance, achieving a Dice coefficient of 93.89%, a mean intersection over union of 91.97%, and an mAP@50:95 of 81.04%. The study demonstrates that the proposed model achieves a high level of accuracy with a notably reduced model size of 18.32 million parameters and a computational cost of 33.50 GFLOPs. This indicates an optimal balance between precision and efficiency, making it well-suited for industrial applications. The research conclusively shows that the model effectively fulfills the dual requirements of high accuracy and a lightweight architecture for segmenting shaking table mineral zones. By incorporating specific advancements in network architecture, the model offers a robust technical foundation for automating shaking table control systems. This development has the potential to significantly improve beneficiation efficiency and consistency, marking a substantial advancement in intelligent mineral processing. Future research will focus on further validating the model’s generalization capabilities across a broader range of industrial operating scenarios.

This study systematically investigated the effects of loading rate and stress amplitude on the mechanical properties of skarn under cyclic loading by conducting variable-rate cyclic loading tests in conjunction with microstructural analysis. The compositional and structural characteristics of skarn were elucidated, and its dynamic shear modulus, damping ratio, and damage evolution law were comprehensively examined. The test specimens were derived from roof core samples of a lead-zinc mine in Yunnan, China, which were subsequently cut, ground, and polished to meet standard specifications. X-ray diffraction （XRD） and polarizing microscopy analyses confirmed that the primary mineral constituents are ilvaite （26.1%）, actinolite （42.6%）, and calcite （16.9%）. Notably, ilvaite and actinolite, which possess higher hardness, collectively constitute approximately 60% of the composition and play a crucial role in inhibiting microcrack propagation. The experiments were conducted using the YAW-2000 servo-controlled rock mechanics testing system, supplemented with the YYSJ50 extensometer （Linear Variable Displacement Transducer, LVDT） for precise deformation monitoring. A cyclic loading scheme comprising two distinct paths—constant amplitude and incremental amplitude—was developed, incorporating three different loading rates （2 kN/s, 4 kN/s, 6 kN/s） for each path. Fifteen cycles were executed for each group to simulate various seismic loading conditions. The findings indicate that the shear modulus increases with rising stress amplitude but exhibits a declining trend as the number of cycles increases within the same group. This decrease is particularly pronounced under low loading rate conditions. The damping ratio follows a “concave-shaped” evolution pattern, initially decreasing and then increasing with the number of cycles, and generally diminishes as the loading rate increases. This suggests that higher loading rates inhibit the material’s energy dissipation capacity. Regarding damage analysis, the damage evolution model, based on axial strain, effectively elucidates the cumulative process of rock damage. The damage variable demonstrates an S-shaped growth curve with an increasing number of cycles, with damage accumulation being more pronounced under low loading rate conditions. Furthermore, the analysis of fracture mechanisms reveals that the primary cracks in skarn subjected to cyclic loading exhibit oblique shear characteristics, which starkly contrast with the vertical tensile cracks observed under monotonic loading. As the stress amplitude increases, the width of the primary cracks decreases, and the number of secondary cracks diminishes, indicating that the loading method significantly influences the rock’s failure mode. This study systematically demonstrates that loading rate and stress amplitude are critical factors in regulating the dynamic mechanical behavior of skarn. The developed damage evolution model, along with the elucidated damping and stiffness response laws, provides a crucial theoretical foundation and experimental reference for safety assessment and structural design in seismic engineering, mining, and related geotechnical fields.

This study proposes a coupled constitutive model for the stress relaxation of the anchor-saturated clay system, grounded in fractional calculus theory. The anchor is modeled as a linear elastic body due to its considerably higher stiffness and negligible rheological effects under service stress levels. In contrast, the saturated clay is represented by a fractional-order generalized Kelvin model, whose parallel structure effectively encapsulates the “memory effect” and “stage-wise stabilization” features—characterized by rapid initial decay followed by gradual convergence—commonly observed in engineering practice. The use of the Riemann-Liouville fractional derivative, along with the two-parameter Mittag-Leffler function, provides a unified theoretical framework for describing material memory effects and continuous relaxation characteristics. To achieve high-precision parameter identification, we propose a hybrid optimization strategy that integrates the adaptive hybrid differential evolution（AHDE） algorithm with the Levenberg-Marquardt （L-M） algorithm. The AHDE, featuring adaptive parameter mechanisms and sub-population mutation strategies, conducts a global search, while the L-M algorithm subsequently performs local refinement. This approach effectively addresses the challenges of non-convexity and multi-parameter coupling inherent in fractional-order constitutive models. The strategy’s validity is confirmed using prestress monitoring data from the 71# anchor bolt, which is equipped with a vibrating wire pressure cell at the Youyiguan Intelligent Port freight corridor slope project in Guangxi, China. The monitoring data exhibit a characteristic two-stage evolution, marked by rapid initial decay followed by slow stabilization. The findings indicate that the model effectively replicates the complete stress relaxation process, achieving an R² value of 0.9517, and surpasses the standalone Levenberg-Marquardt（L-M）, least squares, genetic algorithm, and particle swarm optimization methods in terms of both fitting accuracy and residual stability. Sensitivity analysis elucidates that the fractional order predominantly governs the relaxation rate, the viscosity coefficient dictates the degree of retardation, the soil elastic modulus primarily influences the initial anchoring force, and the anchor elastic modulus is crucial for sustaining long-term pre-stress levels. This study presents a comprehensive framework that integrates fractional-order constitutive modeling, hybrid optimization-based parameter identification, and mechanistic parameter analysis, providing both theoretical insights and practical guidance for the analysis of long-term prestress relaxation and the engineering design of anchored geotechnical structures in soft ground.

To examine the multi-scale damage effects of deep sandstone subjected to high-temperature conditions, a comprehensive analysis was conducted using uniaxial compression tests, micrometer-scale computed tomography（CT） scanning, scanning electron microscopy（SEM）, and X-ray diffraction（XRD）. This study systematically investigates the mechanisms underlying the degradation of mechanical properties and structural deterioration. The findings indicate that as the heating temperature rises from 25 ℃ to 800 ℃, the compressive strength of sandstone demonstrates significant nonlinear evolution, transitioning from high-strength and low-ductility to low-strength and high-ductility mechanical behavior. At a temperature of 800 ℃, the rate of strength degradation in sandstone reaches 38.1%. Additionally, the porosity of the sandstone increases markedly from an initial 1.68% to 6.35%, accompanied by an increase in the heterogeneity of pore distribution. Under conditions of elevated temperature, the pore evolution in sandstone progresses through distinct stages, including microcrack closure, initiation, and coalescence, ultimately resulting in a damage pattern characterized by a thermal fracture surface. The absolute permeability of sandstone increases by 135.1% at high temperatures, exhibiting a proportional relationship with porosity, thereby affirming the predominant influence of pore structure on permeability performance. These physical and chemical transformations, encompassing the evaporation of bound water, crystal expansion, and mineral decomposition, fundamentally driving the multi-scale thermal damage effect observed in sandstone. The three critical temperature thresholds of 200, 400, 600 ℃ correspond to the key processes of dehydration, mineral decomposition, and phase transformation, respectively, under high-temperature conditions. Collectively, these processes dictate the evolution of the macroscopic mechanical properties of sandstone.

This study investigates the mechanical properties and failure characteristics of grouting-filled fractured rock masses by examining the influence of fissure inclination, circular hole radius, and filling conditions on the mechanical behavior and strain field evolution of specimens with combined defects. This is achieved through uniaxial compression tests and the application of digital image correlation(DIC) technology. The findings reveal that the peak stress and crack initiation stress of filled specimens are significantly greater than those of unfilled specimens. For both specimen types, peak strength and crack initiation stress increase with fissure inclination angle, while they exhibit no significant dependence on the circular hole radius. The evolution of the principal strain of cracks is independent of fissure size and inclination, correlating instead with the mechanical behavior of the rock at various damage stages. This provides a foundation for determining the characteristic stresses of fractured rock. In specimens without filling, strain localization zones during the elastic phase initially form around the combined defects and progressively migrate toward the defect tips. In contrast, in cement-filled specimens, the maximum strain remains concentrated within the filling zone for a prolonged duration, only transitioning to the defect tips following the fracture of the filling material. Based on the mechanisms and locations of initiation, the crack initiation modes in specimens with combined defects can be classified into four distinct categories. Additionally, the failure patterns, determined by the formation and coalescence of secondary cracks, are categorized into three types of tension-shear composite failure modes. Importantly, both the crack initiation and failure modes are predominantly influenced by the fissure inclination angle, with no significant correlation to the radius of the circular hole or the filling conditions.

This study employs field tests and theoretical analysis to examine the factors influencing the anchorage force of split-set bolts and the evolution of anchorage strengthacross various time scales. Specifically, it assesses the impact of different anchorage lengths and diameters on the initial anchorage force of the bolts. Additionally, by integrating field monitoring with numerical simulation, the research elucidates the temporal and spatial variation patterns and the underlying mechanisms governing bolt anchoring performance. The findings indicate that the initial anchorage force of the bolt exhibits a linear and positive correlation with bolt length and increases with thedifference between the bolt and borehole diameters, although the rate of increase gradually diminishes. In the short term, the redistribution of stress in the surrounding rock induces further deformation of the bolt, resulting in an upward trend in pullout resistance. Furthermore, the non-uniform stress distribution induced by the cross-sectional structure of the roadway significantly influences the anchoring strength. Specifically, the stress concentration at the arch foot enhances the“clamping”effect on the bolt, leading to a 40.9% increase in anchorage force at the arch foot within 30 days, surpassing the 32.0% increase observed at the straight wall. Upon completion of the surrounding rock stress redistribution, the pullout resistance of the bolt stabilizes around 60 days. Over extended service periods, the anchorage force gradually diminishes due to stress fatigue and corrosion of the bolt rod. Four years post-installation, the average pullout force reduces to 88.9%（45.30 kN） of the initial resistance, and after nine years, it declines to 21.5%（17.03 kN）, falling short of the design specifications. The quantitative data provided in this study serve as a reference for the informed selection and durability assessment of roadway support systems in mining engineering.

Limestone mining frequently results in the formation of high and steep rock slopes characterized by poor stability and challenging conditions for vegetation restoration, primarily due to unsustainable or excessive exploitation practices. The ecological rehabilitation of such mines has consistently posed significant challenges. Traditional regreening techniques, which often rely on singular approaches, have proven inadequate in addressing the adverse environmental conditions and the complexities of soil and water conservation. Consequently, there is substantial practical and applicative value in developing an effective and scalable comprehensive restoration strategy. The Tianluoshan limestone mine, located in the Pinggui district of Hezhou City, Guangxi, serves as a pivotal case study within the autonomous region’s major restoration initiatives, aimed at addressing the ecological rehabilitation of high and steep rock slopes in limestone mines. To optimize the outcomes of ecological restoration efforts, the overall slope of the Tianluoshan limestone mine has been stratified into three distinct regions: A, B and C. The C region has been designated as the initial focus of research, with findings to be disseminated and implemented based on the results of the study. During the test, based on the vertical differentiation characteristics of the slope in area C, the area was stratified into three sections from top to bottom. A comprehensive restoration strategy, comprising “engineering slope protection, substrate improvement, and vegetation reconstruction” was proposed through an analysis of the geological and ecological attributes of the test area. Three restoration technologies were evaluated. Considering the unique geographical context of the mining area, the “ecological rod + hanging net guest soil spray seeding” technology was selected. This was further enhanced by incorporating an appropriate seed formula tailored to the geological conditions of the mining area, resulting in a technical combination of “suitable seed formula + ecological rod + hanging net guest soil matrix spray seeding.” The findings indicated that this technological combination was pivotal for comprehensive restoration. The seed formula included common pioneer species for slope ecological restoration, such as Bermuda grass, Pueraria lobata, ryegrass, and cogongrass, which are characterized by their tolerance to poor soil, strong stress resistance, and well-developed root systems. The implementation of ecological rods effectively reduces the runoff velocity on slopes, thereby contributing to sand retention and soil stabilization. The technology of spray seeding with a hanging net soil matrix involves securing the slope surface with galvanized iron wire mesh, followed by the application of an enhanced matrix comprising humus, organic fertilizer, and water-retaining agents. This process establishes stable environmental conditions conducive to plant growth. The integration of these technologies can rapidly and cost-effectively enhance vegetation coverage on slopes. Considering the variations in slope gradient and damage severity across the three test sections in the slope C area, slope classifications of 60°, 71° and 82° were established, along with an assessment of the damage morphology of the slope surface. This informed the design of differential repair techniques and spray thicknesses, leading to the development of a technical combination suitable for the ecological restoration of high and steep rock slopes in limestone mines. Monitoring the growth height of two representative plant species, thatch and pig feces, over a six-month period revealed that both species exhibited strong adaptability across all test sections, with continuous increases in growth height observed. The vegetation coverage rate achieved the anticipated target in the short term, resulting in the formation of a preliminarily stable plant community. The Pearson correlation coefficient analysis was employed to examine the strong correlation between temperature, rainfall, and plant growth efficiency, thereby confirming the adaptability of the ecological restoration technology combination utilized in this study within the limestone region. Given the favorable outcomes of the experiment, this technological combination is being applied to the ecological restoration of the high and steep rock slopes throughout the Tianluoshan limestone mine. The findings of this study offer valuable reference and guidance for the ecological restoration of high-steep rocky slopes with analogous geological conditions.

The author developed an evaluation index system and model to assess the security of China’s rare earth resource industrial and supply chains from three perspectives: resource-acquisition security, resource-conversion security, and resource-circulation security. This study evaluates the security of these chains from 2000 to 2023. The primary factors affecting security were identified using the obstacle degree model. Subsequently, the coupling and coordination among the three primary indicators were assessed using a modified coupling coordination model. The findings are as follows: （1） The security of China's rare earth industrial and supply chains remained stable from 2000 to 2011 but experienced irregular declines from 2012 to 2023, with the order of security being resource-circulation security>resource-acquisition security>resource-conversion security. （2） Resource-acquisition and resource-conversion security are identified as the principal impediments. The challenges are rooted in import concentration, recycling rates, product value-added rates, application-technology competitiveness, energy consumption per unit, and resource consumption coefficients. From 2000 to 2023, there has been a decline in the coupling and coordination of the rare earth industry and supply chain security. Enhancing and refining the security-improvement strategies can enhance coordination.