To solve the problems of strong subjectivity, poor dynamic adaptability, and low evaluation efficiency in the resource development of closed/abandoned mines, a multi-dimensional evaluation index system with a three-tier framework of "target layer, criterion layer, and index layer" was constructed under the guidance of the collaborative concept of "energy-oriented, resource-oriented, and function-oriented" utilization. By integrating algorithms such as Analytic Hierarchy Process (AHP), Light Gradient Boosting Machine (LightGBM), and Isolation Forest, an intelligent model for dynamic weight optimization and consistency check was constructed. The intelligent evaluation system for closed/abandoned mine resources based on adaptive AHP was developed using Java language, with the Vue. js and Spring Boot frameworks, and technologies including MySQL, Redis, Apache POI, and Docker. In the system, functions such as data import, hierarchical analysis calculation, and result visualization are realized, and the shortcomings of traditional evaluation methods, such as static weights and excessive manual intervention, are overcome. A case study was conducted under the actual conditions of the Longdong Coal Mine. The results show that the system can accurately reflect the characteristics of the mine resources and exhibits good practicality. The research results can provide a replicable technical path for the intelligent evaluation of closed/abandoned mine resources.

In view of the mining integrated energy system suffers from multiple source-load uncertainties including fluctuating wind and photovoltaic output, dynamic variation of mine production load and unstable associated energy output after the integration of new energy such as wind power and photovoltaic power, which greatly increases scheduling complexity and makes it difficult to guarantee energy efficiency, a scheduling method integrating uncertainty analysis and multi-level collaboration optimization was proposed. Firstly, an energy flow model covering source-grid-load-storage was constructed, and a multi-scale source-load uncertainty interval model was established to quantify fluctuation risks. Secondly, a multi-time scale collaborative scheduling framework of day-ahead, intra-day slow layer and intra-day fast layer was designed, and the NSGA-Ⅱ algorithm was improved by adopting a time series segmentation strategy to realize the global optimization of operational cost and energy efficiency. Simulation results based on the integrated energy system of Datong Mining Area show that the system operation cost is reduced to 170 500 yuan, the renewable energy utilization rate is increased to 89.1%, the carbon emission is decreased to 6.83 t, the load tracking error is cut down to 18.9 kW, and the peak shaving rate reaches 17.2%. In addition, the average single-time period solution time of the scheduling method based on series segmentation NSGA-Ⅱ is only 7.0 ms, which is significantly superior to that of traditional methods. The research results verify the effectiveness of the energy scheduling method integrating source-load uncertainty and multi-level collaboration in improving the operational efficiency, energy conservation and emission reduction level of mine energy systems. Feasible scheduling strategies and algorithm support are provided for the efficient and low-carbon operation of mining integrated energy systems under complex uncertain conditions.

In the process of mine exploration and production, energy consumption loads such as drilling rigs and ventilation are intertwined with building heating and hot water loads, and the mining area is rich in resources such as mine water waste heat and associated gas. Traditional energy scheduling methods are difficult to effectively deal with them. Therefore, an optimal scheduling model of mine integrated energy system (MIES) integrating photothermal power station and multi-source heat pump was proposed to improve energy efficiency and low-carbon level. The photothermal molten salt heat storage and multi-source heat pump group work together to build an electric-thermal collaborative supply network that adapts to the rhythm of mine production, and the multi-objective particle swarm optimization algorithm was introduced to optimize the economy and low carbon of the system. The results show that the weekly operating cost of the mine energy system is reduced to 331 700 yuan, the total carbon emission is 39.44 t, and the renewable energy consumption rate reaches 92.54%. The system effectively ensures stable heating in the mining area, with temperature fluctuations controlled within ±1.2 ℃. The utilization rate of the photothermal heat storage device reaches 92.17%, and the average coefficient of performance of the heat pump group rises to 4.47. The proposed model can fully integrate and utilize multi-energy sources in mining areas, effectively improving the economic and environmental benefits of the mine production system, and providing crucial technical support for the construction of green mines.

To improve the capability of Fiber Bragg Grating (FBG) sensors in mine safety monitoring systems to address the cross-sensitivity problem of temperature and strain, a high-precision cross-sensitivity decoupling monitoring model was constructed by integrating a dual-grating temperature compensation method and a Gaussian process regression modeling method improved by the particle swarm optimization algorithm. The experimental results indicate that the proposed method outperforms traditional methods in both wavelength shift data fitting and prediction accuracy. The monitoring system achieves high-precision measurement of temperature and strain data in the mine environment, with the minimum monitoring error being only 0.04 mm and the fitting degree R² reaches 0.912. The system realizes high-precision dual-parameter monitoring in the mine environment, where the monitoring accuracy of temperature and strain reaches 0.961, and the data transmission rate increases by 36% compared to photosensitive and electronic sensors. This demonstrates that FBG sensors possess certain advantages in the dimensions of acquisition accuracy and real-time performance. The research results provide a reusable theoretical framework for innovation in mine safety monitoring and lay a methodological foundation for the evolution of intelligent monitoring systems.

To achieve the effective recovery of iron resources from solid waste, a combined recovery process of reverse flotation, magnetizing roasting, and magnetic separation was proposed, taking a low-grade iron tailings resource in Jingzhou, Hubei as the research object, to efficiently separate the weakly magnetic iron resources in the tailings. Mineralogical analysis indicates that the iron grade of the raw ore is 18.72%, and the ore mainly consists of weakly magnetic hematite and limonite, featuring a fine dissemination size and a high gangue content. Reverse flotation pretreatment was adopted to remove aluminosilicate gangue, thereby reducing the processing volume and energy consumption of subsequent processes. The reverse flotation process parameters were optimized through experiments. Under the conditions of a grinding fineness of 75%, a pulp pH of 9, a soluble starch dosage of 1 500 g/t, and a dodecyl amine dosage of 400 g/t, the iron recovery of reverse flotation roughing reaches 83.07%. After one cleaning stage, the total iron grade of the concentrate increases to 43.60%. Through single-factor experiments, the optimal parameters for magnetizing roasting and magnetic separation are determined as follows: a roasting temperature of 650 ℃, a roasting time of 30 min, a pulverized coal dosage of 6%, and a magnetic induction intensity of 180 mT. This process achieves the directional transformation of weakly magnetic hematite and limonite into strongly magnetic magnetite. After roasting, the magnetic iron grade increases from 0.20% to 43.12%, and the iron grade of hematite and limonite decreases from 38.16% to 1.02%. This combined process realizes the efficient recovery and enrichment of iron resources from the tailings, which provides a technical reference for the resource utilization of tailings.

Hematite is the main associated mineral in a rutile ore deposit in Hebei Province. The rutile particles are fine and intergrown with or enclosed by hematite. Conventional magnetic separation has poor separation effect, making it difficult to achieve effective separation of iron and titanium. Reduction roasting has been proven as an effective technological approach for achieving efficient liberation of fine-grained iron ores from associated gangue minerals. A mineral quantitative automatic analysis system and scanning electron microscope (SEM) were adopted to clarify the mineral composition, element distribution and other information of the samples. The combined process of deep reduction and magnetic separation was adopted to treat the titanium-bearing hematite rough concentrate. Thermodynamic calculation was used to simulate the reaction behaviors of iron minerals and gangue minerals during the reduction process. The optimal experimental conditions were determined as follows: reduction temperature of 1 623 K, reduction time of 120 min, C/O molar ratio of 2.0, and magnetic field intensity of 85 mT. Under the optimal conditions, the metallization rate of reduced products reaches 78.94%. The total iron grade and total iron recovery of iron concentrate are 89.08% and 88.39%, respectively. The TiO₂ grade and TiO₂ recovery of titanium concentrate are 36.67% and 71.88%, respectively, showing favorable mineral processing and smelting indexes.

To solve the problem of the influence of disturbance induced by deep approach mining on roadway surrounding rock stability, Sanshandao Gold Mine was taken as the engineering background. Combined with FLAC3D numerical simulation and on-site monitoring data, the failure evolution laws of surrounding rock in sublevel roadways and stope main roadways under different approach parameters and stoping sequences were compared and analyzed. According to the displacement and stress distribution characteristics of roadways, the mining schemes were optimized. The results show that under the disturbance of approach mining, the displacement of roadway roof increases nonlinearly in four stages with the advancement of mining process. The displacement of stope main roadways is generally larger than that of sublevel roadways, and the stage with the fastest growth rate of roof displacement differs among different mining schemes. Thestress concentration levelin the sidewalls of stope main roadways and sublevel roadways is higher than that in the shoulders, and the stress growth rate on the right side of sublevel roadways is significantly greater than that on the left side, exhibiting asymmetric characteristics. In addition, when upward approach mining is adopted, the stress in stope main roadways undergoes obvious staged mutations, while the stress increaseis relatively gradual under downward approach mining. When the approach width increases from 4 m to 5 m, the increments of roadway stress and displacement are relatively small. However, when the approach width increases from 5 m to 6 m, the variation of approach width exerts a remarkable influence on roadway stability. Therefore, based on a comprehensive analysis of roadway stability and mining efficiency, the downward approach mining scheme with a width of 5 m better meets the requirements of on-site safe production. The on-site monitoring results further verify the reliability of parameter optimization. The research results can provide references for the layout and stability control of deep roadways.

Aiming at the surrounding rock control problems of gob-side entry retaining under the condition of deep water-rich composite roof, the support design and stress analysis were carried out. By analyzing the influence mechanism of composite roof structure and water-rich environment on surrounding rock stability, the limitations of traditional support methods in controlling continuous deformation and floor softening were pointed out. The collaborative control technology system was proposed as follows. Firstly, the constant resistance anchor cable with a length of 11.8 m was used for three rows of vertical roof support, and the two-way shaped charge blasting roof cutting technology was combined to block the lateral stress transmission in the goaf. Secondly, "one beam and four columns" hydraulic support was set up in the dynamic pressure area to strengthen the support. Thirdly, in the drenching section, C20 concrete bedding and grouting anchor cable joint technology were used to control the water seepage softening of the bottom plate. The engineering application results show that the proposed control system reduces the time from severe deformation to stability by more than 40%, the maximum cumulative convergence of the left side of the return air chute is controlled within 940 mm, and the floor heave is significantly reduced within 660 mm. The proposed collaborative control technology can effectively deal with the complex geological conditions of water-rich composite roof, and realize the long-term stability control of gob-side entry retaining. The research results can provide a reliable technical basis for non-pillar coal mining under deep and complex geological conditions.

To address the challenge of the unclear spatiotemporal coupling mechanism of the wind temperature field in dynamic excavation roadways during the thermal hazard control of deep high-temperature mines, a three-dimensional unsteady heat transfer model of the dynamic excavation process was constructed. A dimensionless time F_ov characterizing the excavation speed and the traditional dimensionless distance X were introduced to establish a spatiotemporal binary relationship Θ(F_ov, X) for the temperature field. The spatiotemporal coupling relationship of the dimensionless temperature in the excavation roadway was obtained through iterative inversion based on the Gauss-Newton method, further revealing the nonlinear mechanism of the effect of inlet air temperature on thermal hazard regulation. The results show that the evolution of the dimensionless temperature over time and space follows an exponential-quadratic time-varying relationship (Mean Relative Error MRE=1.1%). The temperature gradient is positively correlated with distance and negatively correlated with time. The initial cooling effect of low-temperature air supply is significant, but after long-term ventilation, the air flow and surrounding rock gradually approach thermal equilibrium, and the cooling efficiency attenuates by 26.3%. Thermal hazard control projects should integrate surrounding rock thermal management with localized cooling to improve cooling sustainability. A reduction in the inlet air temperature intensifies the nonlinear variation characteristics of the air temperature, increasing the MRE of the dimensionless temperature spatiotemporal coupling model from 1.10% (30 ℃) to 1.81% (20 ℃), while still meeting engineering accuracy requirements. The air temperature response in the area near the heading face is the most sensitive. When the inlet air temperature rises from 20 ℃ to 30 ℃, the total temperature rise near the heading face area is 42.1% higher than that in the roadway exit area. Taking a heading face air temperature threshold of 26 ℃ as the constraint, a dynamically designed inlet air temperature that meets the cooling requirements was derived.

Aiming at the extraction challenges of high-grade ore bodies in deep fractured surrounding rock, the applicability of the drift filling mining method was explored using a copper-gold mine as the engineering background. Through core sampling, uniaxial compression and Brazilian splitting tests, combined with the Hoek-Brown and Mohr-Coulomb strength criteria, the key mechanical parameters of the surrounding rock and backfill were obtained. Subsequently, numerical simulations on overhand and underhand drift filling mining methods were conducted to analyze the displacement characteristics of the surrounding rock under corresponding support conditions, and scheme optimization was achieved by integrating technical and economic indicators. The results indicate that the overhand drift filling mining method is applicable to ore bodies with good to moderate rock mass stability, whereas the underhand drift filling mining method is more suitable for ore bodies featuring extremely fractured and highly unstable rock masses. For both drift filling mining methods, the total displacement of the surrounding rock remains relatively small; however, the displacement distributions differ due to variations between the roof and the floor. An economic comparison reveals that the underhand drift filling mining method incurs higher mining and filling costs (4.01 yuan/t higher than the overhand drift filling mining method), while its support costs are lower (0.313 yuan/t lower than the overhand drift filling mining method). Based on a comprehensive evaluation, the overall application of the overhand drift filling mining method is recommended, with the underhand drift filling mining method reserved exclusively for localized areas containing highly fractured surrounding rock.