To investigate the deformation characteristics and support optimization methods of roadways excavated in backfill under complex stress conditions,the stress distribution and roadway deformation failure characteristics of a copper mine in Serbia were surveyed.The stability of the backfill was evaluated based on a modified coal mine roof rating(mCMRR)system,and the support parameters for roadways excavated in the backfill were optimized by combining the analysis of roof bolt systems(ARBS)with numerical simulation.The results show that a high horizontal stress difference coefficient,fractured rock strata,and non-uniform stress transfer induced by intensive multi-level mining are the main causes of the complex stress regime in the mine,with roadway deformation characterized by roof crushing,apex failure,and shear staggering.The mCMRR value of the backfill in the bottom structure of the preliminary stope is 60.5,rated as"moderate"with a safety factor of 2.14.For the combined boltmesh-shotcrete support system in roadways excavated in the backfill,the existing bolt pattern can be optimized from 0.8 m×1.0 m to 1.0 m×1.2 m.Numerical simulation and industrial tests indicate that a support scheme consisting of roof bolts spaced at 1.0 m×1.2 m,ϕ6 mm@100 mm×100 mm steel mesh on the roof and sidewalls,and a 50 mm shotcrete layer,can effectively form a cooperative load-bearing structure of roadway and surrounding rock.The stress,displacement,and plastic zone distributions in the roof and sidewalls meet safety requirements,and the support cost is reduced by 8.3%.

To accurately constrain the emplacement age of intrusive rocks in the Liziyuan Gold Deposit,West Qinling Orogenic Belt,elucidate their petrogenesis and tectonic setting,and clarify their constraints on the regional gold mineralization timing,whole-rock analysis,zircon U−Pb dating,and trace element analysis were carried out on monzogranite and syenite.Combined with various zircon trace element discrimination diagrams,the rock types,source characteristics,and tectonic settings were systematically identified.The dating results show that the emplacement ages of monzogranite and syenite are 217.2 Ma±2.6 Ma and 210.4 Ma±2.3 Ma,respectively,indicating they were formed during the early Indosinian magmatic event.Zircon trace element characteristics reveal that the monzogranite and syenite exhibit typical Ⅰ-type granite affinity and were mainly derived from continental crustal materials.Zircons display positive Ce anomalies and negative Eu anomalies,suggesting that the magma formed under relatively high oxygen fugacity and possibly underwent plagioclase fractionation.Tectonic discrimination indicates that the monzogranite and syenite were emplaced during the transition from anorogenic to orogenic settings,accompanied by crustal thickening.Comprehensive analysis demonstrates that the monzogranite and syenite were formed during the Late Triassic Indosinian and were generated by partial melting of continental crust materials under a collisional orogenic setting.Integrated with previously published zircon ages for magmatism and mineralization,a complete metallogenic temporal sequence of"pluton emplacement(210–214 Ma)→hydrothermal mineralization(207 Ma)"is established,and a dual-constraint model of"pluton age+mineralization age"is proposed.This study provides key geochronological and geochemical evidence for further understanding the magma-mineralization evolution in the West Qinling Orogenic Belt.

To address the massive waste rock and tailings generated during ore mining processes,this study conducted Brazilian splitting tests on waste rock-tailings backfill specimens to achieve efficient utilization of general solid waste in mines and gain insights into the influence mechanisms of tensile strength and energy dissipation characteristics in waste rock−tailings backfill.Response surface methodology was employed to analyze experimental results regarding tensile strength and energy dissipation.The research systematically investigated the effects of varying waste rock addition rates,ash-sand ratios,slurry concentrations,and curing ages on the backfill’s tensile strength and energy dissipation.Results demonstrate that stress–strain curves of waste rock-tailings backfill exhibit distinct four-phase features including compaction,elastic deformation,yielding,and fracture.Under identical slurry concentrations,tensile strength increases with rising ash-sand ratios,waste rock addition rates,and prolonged curing ages,with the ash-sand ratio at 1∶4 showing the most significant impact under controlled conditions.The response surface-based tensile strength prediction model of the backfill achieves a multiple correlation coefficient of 0.9687,revealing the influence hierarchy:curing age>ash-sand ratio>waste rock addition rate.Elastic strain energy density accounts for over 98%of total energy during backfill fracture,indicating that abrupt release of internal elastic strain energy constitutes the primary failure mechanism in Brazilian splitting tests.The research results can provide a theoretical basis for the optimization of waste rock−tailings backfill ratio in underground mines and for maintaining the stability of underground goafs and stopes.

Paste backfill technology is one of the key supporting technologies to ensure national mineral resource security and implement the Two Mountains Theory.Nevertheless,the traditional extensive,experiencedependent,and mine-wide homogenized paste backfill design fails to satisfy the engineering requirements of goafs in terms of spatial difference,functional difference,and environmental constraint difference under complex mining conditions.To solve the above problems,the concept of personalized paste backfill was proposed.Taking differentiated paste performance requirements and precise customization of paste materials as the core,it achieved multi-objective directional regulation of paste backfill materials by identifying performance indexes of different mining areas and working conditions and combining mineral fingerprint characteristics of solid wastes.This paper elaborated the differentiated performance requirements of paste and precise customization of paste materials.The differentiated performance requirements of paste mainly cover mechanical properties,pipeline transport performance,consolidation forming performance,environmental safety,low carbon and emission reduction,and other aspects.The precise customization of paste materials involves raw material system identification,material structure optimization,cementitious system construction,functional component addition,and whole-process quality control.It is indicated that future research should be strengthened in goaf demand identification,solid waste mineral fingerprint analysis,intelligent decision-making of material proportioning,and system dynamic regulation methods,so as to promote the high-quality development of paste backfill towards refinement,intelligence,and customization.

In response to the technical challenges faced by gold mines employing cyanidation gold extraction processes,such as the scarcity of backfill aggregates,the instability of traditional backfill performance,and high costs,this study conducted experimental research on lightweight energy-absorbing paste backfill.The basic physicochemical properties and energy absorption characteristics of the lightweight energy-absorbing backfill were systematically evaluated using XRD,slump and bleeding rate tests,uniaxial compressive strength tests,and triaxial compression mechanical behavior studies.The results indicate that when the dry density of the lightweight energyabsorbing backfill is between 500 kg/m³ and 650 kg/m³,the slurry bleeding rate ranges from 1.20%to 1.45%,achieving stable structural flow paste backfill.After 3 d of curing,the uniaxial compressive strength reaches 0.6–1.0 MPa.Furthermore,under triaxial confining pressure conditions,the material’s strength exhibits a positive correlation with increasing pressure,demonstrating excellent energy absorption characteristics.This research provides technical support for the subsequent promotion and application of lightweight energy-absorbing paste backfill in gold mines.

The Shanggong Gold Deposit has proven gold resources exceeding 140 t,reaching a super-large scale.In recent years,deep validation boreholes have encountered polymetallic orebodies,which have raised new requirements for understanding its mineralization.Carbon,hydrogen,and oxygen isotope analyses were conducted on quartz and ankerite from different mineralization stages of the Shanggong Gold Deposit.The results show that theδ¹⁸O_{H_(2}O) values of quartz range from−2.5‰to 1.6‰,with an average of−0.4‰;theδD_{H_(2}O)values range from−94.7‰to−86.5‰,with an average of−90.6‰,which are close to magmatic water.Theδ¹⁸O_{H_(2}O)-δD_{H_(2}O)diagram indicates a transitional trend from meteoric water to primary magmatic water for the ore-forming fluids of gold deposits in the region.Theδ¹³ C_{CO_(2})values of quartz range from−11.9‰to−5.3‰,with an average of−7.9‰,which are significantly higher than those of organic matter and freshwater CO₂ but lower than those of marine carbonates,and they are comparable to those of the crust,mantle,igneous rocks/magmatic systems,and atmospheric CO₂.Theδ¹³C_V-PDB values of ankerite range from−2.0‰to−1.2‰,with an average of−1.4‰,which are higher than theδ¹³C composition of other carbon reservoirs except marine carbonates.Mantle degassing and magmatic processes are the main sources ofδ¹³C in the Shanggong Gold Deposit.However,there is an obvious gradual transition phenomenon among gold deposits in the region,which has been significantly influenced by low-temperature alteration and meteoric water.Differences in structural settings or magmatic activity backgrounds have led to variations in theδ¹³C sources of the gold deposits.

In response to the problems of low production efficiency,high boulder yield,and high comprehensive costs encountered in the upward horizontal cut-and-fill mining method at Jinshan Gold Mine,this study conducted a series of research on medium-depth hole blasting parameter optimization technology.Firstly,based on the Livingston blasting crater theory,fundamental medium-depth hole blasting parameters suitable for the rock mass conditions at Jinshan Gold Mine were determined through inversion derivation using single-hole,multihole,and inclined bench blasting crater tests.Subsequently,by utilizing the LS-DYNA numerical simulation software,fluid-structure interaction blasting models for both double-hole and multiple-row hole arrangements were established.A comparative simulation analysis of rock damage and fragmentation effects under different blasting pattern parameters(burden×spacing)was performed,leading to the identification of a 1.4 m×1.2 m blasting pattern as the optimal scheme.Finally,the optimized parameters were validated through field industrial trials.The results demonstrate that the optimized blasting scheme significantly reduces the stope boulder yield,improves the fragmentation uniformity of the blasted ore,and effectively enhances production efficiency.This provides an integrated systematic solution of"experimental study,numerical simulation,and industrial validation"for blasting parameter optimization in similar mines.

As metal mines progressively enter the stage of deep mining,the demands for mine safety as well as green and efficient production have become increasingly prominent.The backfilling mining method has emerged as a vital mining technique for deep ore bodies due to its effectiveness in ground pressure control,improvement of ore recovery rates,and enhancement of underground working conditions.Traditional backfilling mining methods,however,suffer from shortcomings such as high backfilling costs and significant labor intensity.Enhancing backfilling system efficiency,reducing mining backfilling costs,and decreasing workers’labor intensity have become key challenges in promoting backfilling in mines.As a novel solution to these challenges,intelligent backfilling technology has achieved positive results in many mining applications.This paper briefly introduced the basic concepts and principles of intelligent backfilling technology,analyzed the reasons for its rapid development,and provided a detailed overview of the current state of artificial intelligence algorithms in backfilling experiments as well as the construction of intelligent backfilling systems in China.Finally,the difficulties in research on intelligent backfilling technology were discussed,and some ideas for the future development direction of intelligent backfilling technology were provided.

The Laodonggou Gold Deposit is located in the Inner Mongolia section of the Beishan mineralization belt.The main ore bodies are hosted in marble and dolomitic marble of the Yuanzaoshan Group of the Jixian System of the Mesoproterozoic Era.They occur in a layered and lens-shaped manner.According to the ore body’s structure,mineral composition,and oxidation degree,the ore types can be classified into primary copper−gold polymetallic ore,primary gold−silver−lead ore,and cave-type oxidized ore.This study discovered typical submarine hot water sedimentary structures such as bedding-parallel laminated structure,syngenetic breccia structure,convolute bedding structure,and soft-sediment sliding deformation structure in the surrounding rocks of the layered and lens-shaped ore bodies.The study proposed the Middle Proterozoic hot water sedimentary mineralization in the Laodonggou Gold Deposit.The superimposed and modified mineralization in the Laodonggou Gold Deposit is related to the Silurian magmatic−hydrothermal activities and has characteristics of isospatial mineralization and epigenetic mineralization.The formation of cave-type oxidized ore in the Laodonggou Gold Deposit is the result of Quaternary groundwater activity and karstification.The Laodonggou Gold Deposit is a stratabound polygenetic compound deposit.The aggregation of conductive minerals and the formation of the gold deposit are causally related to the geoelectric field conditions.This study has significant implications for promoting the exploration work of Proterozoic stratabound gold deposits in the Inner Mongolia section of the Beishan mineralization belt and the entire Beishan metallogenic belt.

In order to solve the problems of a poor driving environment and low intelligence level of underground load-haul-dump(LHD)vehicle,a simulation study on autonomous positioning and navigation of underground intelligent LHD vehicle was achieved through kinematics analysis,3D model establishment,global map construction,and global path planning.By analyzing the kinematics model of articulated vehicles,the correlation between vehicles’physical parameters was established,and the conditions that the LHD vehicle simulation model needed to meet were clarified.On the Gazebo 3D simulation platform,a simulation model of the LHD vehicle body with sensors and a simulation model of the underground tunnel environment were constructed.The initial position of the LHD vehicle simulation model in the tunnel environment was set to facilitate subsequent autonomous positioning and navigation research.Based on sensor information,a global map was constructed.The AMCL algorithm was used to achieve autonomous positioning of the LHD vehicle simulation model,ensuring that the initial position of the LHD vehicle simulation model was consistent between the Gazebo 3D simulation platform and the Rviz 3D visualization platform.Two algorithms were used for global path planning of the LHD vehicle simulation model from the mining area to the unloading area in underground tunnels,respectively.The simulation results show that the A^*algorithm performs better in this simulation study,providing a technical support for achieving intelligent underground vehicles.