To address the problems of low filling body strength and large surface subsidence in the current filling mining process of a coal mine in Jining, filling materials were prepared with fly ash as the main material and lime, β-gypsum, cement, sodium hydroxide, and compound additives (slag A, AEA-type expansive agent B, cement clinker C) as auxiliary materials. The influence of additive ratio on slurry flow performance, uniaxial compressive strength of filling body, hydration products, and microstructure was explored. The study shows that the flow performance of slurry has no linear relationship with changes in the content of each component in the additive. Under different additive ratios, the initial fluidity of the filling slurry is ≥22.2 cm and the dynamic viscosity is ≤218 mPa•s, which meets the self-flow requirement. When the content of other components is constant, with the increase in the content of components A, B, and C, the filling body strength at different curing ages all shows a trend of first increasing and then decreasing. Under different additive ratios, the hydration products of the filling body cured for 28 days are basically consistent, but there are differences in the intensity of diffraction peaks. The increase in the content of components A, B, and C can effectively improve the compactness and pore development of the filling body. However, when their content is excessive, the microstructure deteriorates. When the content of components A, B, and C is 14％, 6％, and 8％ respectively, the mechanical properties of the filling body are optimal. Its early-age (8 h) strength and long-term (28 d) strength reach 0.75 MPa and 4.33 MPa respectively, with the highest compactness and excellent flow performance.

To address the environmental issues caused by deep mine geothermal hazards and the accumulation of construction waste, waste foam concrete was used as a novel porous support material combined with solid paraffin to prepare phase change thermal storage materials. These materials were used to replace part of the coal gangue at different ratios (referred to as the phase change thermal storage material replacement ratio) as aggregates, and were mixed with cement and fly ash to prepare phase change thermal storage filling body. The microstructural properties of the phase change materials and the filling body were investigated using scanning electron microscopy, while the mechanical and thermal properties of the filling body with different phase change materials were examined. The results indicate that the prepared phase change thermal storage filling body exhibits an uniform and dense microstructure with excellent shape stability, maintaining a stable shape even at elevated temperatures. After comprehensively evaluating the mechanical properties, thermal characteristics, and material economy of the filling body, it is found that at a replacement ratio of 10％, although fluctuations can be observed in compressive strength, thermal storage coefficient, and thermal conductivity, the specific heat capacity has reached saturation. Therefore, controlling the replacement ratio at approximately 10％ is considered the optimal choice. In conclusion, the experimentally developed phase change thermal storage filling body not only meets the compressive strength requirements but also demonstrates excellent thermal conductivity and thermal storage capacity, offering a feasible material solution for geothermal regulation in deep mines and the resource utilization of solid waste.

In order to solve the filling demand of upward drift filling mining method in the broken rock area of a gold mine in Luoyang, fly ash-based foam concrete was used to fill the goaf. The slump test and uniaxial compression test were carried out to explore the influence of fly ash content on the compressive strength of filling body, and the cementitious mechanism of fly ash based foam concrete was analyzed. The results show that the foam concrete can control its flow state through the foaming rate (wet bulk density), and the slump values of the slurry with different cement contents are controlled between 24 cm and 27 cm. At this time, the slurry has a good flow performance and no bleeding phenomenon. Whether fly ash is added or not, the strength of foam concrete specimen can meet the strength requirements of upward drift filling mining method, but the costs of foam concrete materials can be reduced by 46.7％ by adding fly ash, and fly ash-based foam concrete has a good application prospect. The fly ash optimizes the pore structure by generating C-S-H gel and ettringite to improve the later strength of the filling body. In the industrial test of foam concrete, the total volume of goaf is 525 m³, the costs of filling materials are about 55,000 yuan, and the comprehensive filling cost is 42 yuan/t. The filling slurry has good leveling and no bleeding, and the strength of filling body is consistent with the indoor test values. The industrial test of filling has achieved the expected effect and solved the urgent problem of mine filling production.

The third category mineral resources in Yunnan Province are relatively few, with uneven distribution of existing resources and differences in infrastructure construction time and space, resulting in tight supply of sand and gravel aggregates during peak construction periods in some areas. At the same time, affected by the ecological protection red line in Yunnan Province, it is difficult to establish new mining rights for sand and gravel in some areas. Counties (cities, districts) with scarce resources need to import resources from neighboring areas, greatly increasing the cost of using sand and gravel aggregates. In order to efficiently utilize resources and alleviate the pressure of uneven supply of sand and gravel aggregates in local areas, based on relevant laws, regulations, and policy documents, and referring to the experiences of other provinces in classifying third category minerals, field research and evaluation were conducted from three aspects, including resource endowment, market economy, and existing usage. Finally, five mineral types including granite, basalt, dolomite, tuff, and sandstone (other) have been added as the third category minerals. The added mineral types can be used as a supplement to mineral resources in resource deficient areas, while reducing mining management risks and minimizing illegal mining activities, which is conducive to the development and utilization of sand and gravel mineral resources.

The stability of mine shaft is very important to the safety of mining process. Taking the 1^# shaft adjacent to the caving method stope and the filling method stope of a mine as the research object, a three-dimensional numerical model including the pillar caving method, the non-pillar caving method and the drift filling mining method was constructed, and the influence of mining disturbance of different mining methods on the stability of the shaft was analyzed. The results show that the main reason for the shaft failure is the superposition effect of the poor geological conditions of the rock mass in the ore-penetrating section and the mining disturbance. The disturbance caused by the mining of the drift filling mining method has the greatest influence on the maximum deformation value of the shaft, followed by the disturbance caused by the mining of the pillar caving method, and the disturbance caused by the mining of the non-pillar caving method has the least influence. Especially when the caving stope is mined at the same time, the superposition of the mining disturbance effect has a more significant effect on the deformation of the shaft. On the basis of comprehensive consideration of the existing engineering conditions of the mine, aiming at the risk of shaft failure that may be faced in the mining process of the ore body near the shaft in the section from the elevation of +710 m to +830 m, the curtain grouting reinforcement scheme was designed for the 1^# shaft. The reinforcement scheme can ensure the safety of 1^# shaft in the subsequent mining process.

Due to the influence of ore-rock endowment and blasting construction quality, variable cross-section pillars are commonly present in room-and-pillar underground mining mines. To study the bearing capacity effect of variable cross-section pillars, taking the variable cross-section pillar of a limestone mine as the research object, a mechanical model of the variable cross-section pillar was established, the expressions for its stress and safety factor were derived, the relationships between stress, safety factor and factors such as the diameter d of the variable cross-section pillar and the radius R of the variable cross-section area were studied respectively, and the stress distribution characteristic was analyzed. The results show that the stress of variable cross-section pillars changes gradually in the variable cross-section area, and the stress amplitude decreases with the increase of R or d. The safety factor increases with the increase of R, and the rate of change increases gradually. It also increases synchronously with the increase of d. Compared with constant cross-section pillars, variable cross-section pillars have a more uniform stress distribution, a better stress transfer effect at the junction with the roof, a higher safety factor, and better stability. Numerical simulation and engineering examples have verified the reliability of the theoretical calculation results.

Reasonably and effectively determining the uniaxial compressive strength of rocks is of great significance for ensuring the safety of mining rock engineering. Based on two groups of rock uniaxial compressive strength datasets including longitudinal wave velocity, Schmidt hammer rebound value, point load strength, Schmidt hardness, and other indirect indicators, four combination algorithms including PSO-BP, PSO-LSTM, CNN-LSTM, and PSO-BILSTM, were selected. And the optimal rock uniaxial compressive strength prediction algorithm was comprehensively evaluated through 7 evaluation indicators. The results show that the PSO-LSTM algorithm fits well with the predicted values and actual values on two datasets, and all evaluation indicators are high. Based on the metric scoring method to quantitatively analyze the predictive performance of various algorithms, PSO-LSTM can achieve a total high score of 27 and 21 on Dataset 1 and Dataset 2, respectively, demonstrating the highest prediction accuracy. The analysis of input parameter correlation shows that the point load strength has the greatest impact on the prediction of uniaxial compressive strength in Dataset 1, with a correlation degree of 0.735 5. The tensile strength has the greatest impact on the prediction of uniaxial compressive strength in Dataset 2, with a correlation coefficient of 0.829 2. Meanwhile, the predictive performance of each algorithm in Dataset 2 is better, indicating that using input parameters with high correlation with uniaxial compressive strength can effectively improve the predictive performance. The research results can provide a reference for determining the uniaxial compressive strength of rocks.

In order to improve the prediction efficiency and accuracy of uniaxial compressive strength of rocks, a combined model based on convolutional neural network (CNN) and long short-term memory (LSTM) network was proposed and optimized using Newton-Raphson-based optimizer (NRBO). Extensive collection of rock physical parameter experimental data, including point load strength, Schmidt hammer rebound number, porosity, and longitudinal wave velocity, was conducted. After preprocessing, 381 valid samples were retained and visualized for analysis and outlier handling. CNN was used for feature extraction, LSTM captured temporal dependencies, and NRBO optimized hyperparameters such as learning rate, regularization coefficient, and number of hidden layer nodes. The experimental results show that the NRBO-CNN-LSTM model performs the best on the test set, with a coefficient of determination of 0.98, a root mean square error of 6.27, and an average absolute error of 4.82, significantly better than other comparison models, demonstrating stronger fitting ability and generalization performance. This optimization model can effectively integrate multiple physical characteristics of rocks, achieve high-precision and high stability prediction of uniaxial compressive strength, and provide reliable technical reference for engineering practice.

Aiming at the characteristics of roadway surrounding rocks in Baiyinhar mine, such as hard lithology, severe alteration and extremely poor stability, a secondary support scheme for the roadway based on the distribution of the plastic zones was proposed. For the fractured surrounding rocks, based on the results of the point load test and the relevant shaft construction data of the Baiyinhar mine, the physical and mechanical parameters of the rock mass were calculated according to the Hoek-Brown strength criterion. The plastic zone range of the arched roadway was calculated using three equivalent circle radius methods combined with the Fenner formula and the Drucker-Prager (D-P) criterion formula, and the Kastner approximate solution for the plastic zone boundary of the surrounding rock of a circular hole under a non-uniform stress field was obtained. The displacement, stress, and plastic zone distribution after excavation, as well as the effect of the original support, were obtained using numerical simulation. According to the plastic zone distribution of the roadway surrounding rock under the original support, the secondary support for the roof, top corners, and floor of the roadway was conducted. The results show that the equivalent circle radius method of the circumscribed rectangle and the D-P criterion are more suitable for calculating the plastic zone of the roadway in Baiyinhar mine. Combined with numerical simulation, it is found that gold-bearing altered rock is predominantly distributed in the top corners of the roadway. After conducting the secondary support, the deformation of the surrounding rock at the roof and floor was significantly reduced from the original 23 mm to approximately 8 mm and 10 mm, respectively. The stress concentration in the roof was also reduced, and the range of the plastic zone was significantly decreased, which helps to prevent shear failure of the roadway surrounding rock.

A double shear test device without friction between joint surfaces was used to conduct shear tests on anchor cables and the new type of anchor cable with C-shaped tube(ACC), and the effect of preload on the shear properties of the two structures was analyzed. The test results show that the negative effect of preload on the anchor cable is greater than that of the ACC. As the preload is increased from 100 kN to 300 kN, the shear load capacity of the anchor cable is reduced by a maximum of 14.82％, while the ACC is reduced by only 6.53％. Meanwhile, finite element simulation was utilized to further study the shear deformation properties of the ACC. The results show that the higher the preload, the lower the peak shear load and breaking displacement of the ACC, the higher the flexural stiffness of the structure, the earlier the strength of the specimen is mobilized and the faster the specimen fails locally. Under low preload conditions, the breaking displacement of the ACC is greater, which is due to the fact that for the same shear displacement, a lower preload will result in less tensile deformation at the shear plane location of the structure, and will also result in a larger bending angle of the structure at the shear plane location.