The eclogite-type rutile ore resources in China are widely distributed and abundant in reserves. However, most of the rutile ore belongs to primary ore, with low grade, fine embedded particle size, complex ore properties and small difference in surface properties between the rutile and gangue, which brings many challenges to mineral selection. At present, the process of rutile beneficiation is complex, with high production costs and long recovery cycles, resulting in difficulty in effectively developing and utilizing China's rutile resources. Regarding a low-grade eclogite-type rutile ore in Qinghai Province, an experimental study on short process technology for full particle flotation recovery was carried out. The results indicate that the short process technology for full particle flotation recovery has good adaptability to this mine. Under the conditions that the grinding fineness of－0.074 mm accounts for 59.52%, screening particle size of－0.013 mm, the dosage of sodium fluosilicate 700 g/t, the dosage of lead nitrate 300 g/t and the dosage of EM-OL 600 g/t, rutile concentrate with yield of 3.21%, TiO₂grade of 61.70% and TiO₂ recovery rate of 63.14% can be obtained by the flotation process of two roughing and four cleaning to separate the screened desliming raw ore, and rutile can be fully recovered and utilized. This process realizes the short-term recovery of rutile minerals, which can simplify the beneficiation process, save production costs, and be also conducive to subsequent re-election and upgrading.

A high-sulfur and high-silicon bauxite mine in Guizhou was treated with reverse flotation for desulphurization and desilication.The effects of grinding fineness, pH adjuster, activator, collector, foaming agent and inhibitor on flotation desulphurization and desilication were analyzed, and the optimal experimental conditions for flotation desulphurization and desilication of the bauxite mine were determined. The research results show that when the grinding fineness of the raw ore is－0.074 mm accounting for 75.00%, the dosage of sodium carbonate is 1 500 g/t, the dosage of copper sulfate is 100 g/t, the dosage of mixed collector is 300 g/t, and the dosage of foaming agent is 84 g/t, the raw ore is subjected to a closed-circuit test of reverse flotation desulphurization with “one coarse, one fine and two sweeps”, and the desulphurized aluminum concentrate with a yield of 79.27%, a desulphurization rate of 85.58% and a sulfur content of 0.31% is obtained. When the grinding fineness of desulphurized aluminum concentrate is－0.074 mm accounting for 88.00%, the dosage of sodium carbonate is 600 g/t, the dosage of soluble starch is 200 g/t, and the dosage of Y28 collector is 525 g/t, the reverse flotation desilication closed-circuit test of “one coarse, one fine and two sweeps” is carried out, and the aluminum concentrate yield is 64.21%, the Al₂O₃ recovery rate is 68.46%, the Al₂O₃ grade is 59.37%, the aluminum silicon ratio is 5.83, and the sulfur content is 0.32%.

In order to explore the effect of particle-particle interaction on slurry rheology under different electrolyte solutions, quartz and calcite were used as research objects. The effects of Ca²⁺/Mg²⁺ concentration on the apparent viscosity and yield stress of single quartz/calcite slurry and mixed slurry were studied by rotational rheometer. Combined with Zeta potential, DLVO theory calculation and suspension turbidity test, the surface electrical properties, particle interaction and coagulation behavior of mineral particles under different Ca²⁺/Mg²⁺ concentrations were revealed, and the theoretical relationship between particle microscopic action and slurry rheology was established. The results show that the increase of Ca²⁺/Mg²⁺ concentration can reduce the thickness of the electric double layer on the particle surface, enhance the attraction between the particles, promote the in-phase condensation of the particles, and result in the increase of the apparent viscosity and yield stress of the single quartz and calcite slurry, and reduce the turbidity of suspension. The increase of Ca²⁺/Mg²⁺ concentration can weaken the attraction between quartz and calcite, weaken the heterogeneous condensation between them, lead to the decrease of apparent viscosity and yield stress of mixed slurry, and increase the turbidity of suspension. The yield stress of quartz + calcite mixed slurry has a logarithmic relationship with the Debye length of the solution, and has a positive correlation with the square of the surface potential difference between the two different particles.

Mastering the characteristics and functional suitability of mine water is a prerequisite for achieving resource utilization and graded utilization of mine water sources. Taking the mine water in Yushuling Coal Mine as the research object, water samples were collected from different areas for water testing, the types of mine water resource utilization were divided, an evaluation system was established, and the functional suitability of different utilization directions of mine water was comprehensively analyzed. Research results show that the chemical type of mine water is mainly , with a membership degree of 0.812 - 0.991 for Class V water. The content of hydrochemical components is high, and there are three potential utilization pathways for drinking, irrigation, and industrial water. The suitability evaluation results of various types of mine water for drinking are grade Ⅲ and Ⅳ, which are not suitable for drinking.In terms of irrigation and industrial water suitability, there are significant differences in the evaluation results of different types of mine water. The sodium adsorption ratio, Razner stability index of water accumulation in goaf and fissure water are 3 - 10.8 (mmol·L)^1/2and 6.1 - 6.5, respectively, indicating that they have little impacts on soil physical and chemical properties and are basically non-corrosive, making them suitable for irrigation and industrial water use. The saturation index of accumulated water in the burnt area is 0.8 - 1.2, exceeding 0.6, indicating a tendency towards scaling. Generally, it cannot be directly used as irrigation water, but can be used for industrial water use. The water quality of the water tank is severely polluted, with indicators such as soluble sodium percentage (78.4% - 84.5%), magnesium hazard ratio (62.9% - 72.0%), Razner stability index(7.2 - 7.7), and Larson ratio (8.0 - 12.0), indicating that this type of water poses a high risk to soil alkalinity and permeability, and has severe corrosiveness, with poor potential for functional utilization.

Large-scale continuous mining of deep ore bodies is the frontier research direction of deep mining in the future. Aiming at the problem of mutual restriction between the traditional intermittent mining operation mode and the deep intelligent and efficient mining of deep hard rock deposits, a continuous mining operation mode of parallel mining and filling was proposed, which used flexible isolation layer to realize the parallel filling and continuous mining process. The strength distribution of filling body in parallel filling process of high-stage large stope was analyzed by means of theoretical calculation formula and FLAC3D numerical software, and the strength requirements of filling body at different heights of high-stage stope were determined. PFC discrete element software was used to analyze the flow law of ore-filling granular and the deformation damage characteristics of isolation layer in parallel filling and continuous ore drawing. The results show that in the parallel filling and continuous ore drawing process, the 28 d consolidation bearing strength of the filling body at the top and bottom of the stope should be greater than 8 MPa. With the filling and ore drawing, the maximum load of the isolation layer is 57 kPa when it is close to the funnel mouth of the ore drawing. At this time, the isolation layer has obvious concave deformation, and the damage near the pillar area on both sides increases, resulting in obvious tensile and compressive damage. The study can provide reference for the continuous operation of deep ore body mining.

To study the phenomenon of rock burst in deep rock roadway, the true triaxial rock burst test machine was used to study the phenomenon of rock burst induced by cyclic dynamic disturbance under different axial stresses in semi-circular arch roadway with prefabricated straight wall, and the acoustic emission technology was used to monitor the failure process of roadway. Through the rock burst test, it is found that the greater the initial axial static stress, the higher the degree of rock deterioration, the shorter the disturbance time required for rock burst, the faster the cumulative energy rate of the sample, and the more severe the rock burst. The results show that when the axial stress exceeds 76.5% of the peak stress of the rock roadway, the rock burst will occur after the cyclic dynamic disturbance is applied to the specimen. The failure mode of rock roadway is tension-shear combined failure, and the failure mode of crack propagation is closely related to axial stress and dynamic disturbance. Acoustic emission cumulative ringing count is used to describe the degree of rock deterioration, and it is found that the degree of rock deterioration under dynamic disturbance is positively correlated with the initial axial static stress.

A gently inclined and multi-layer poor ore vein contains lead-zinc, magnetite and sulfur-copper minerals at the same time. Based on the characteristics of the ore body and its low grade, a pseudo inclined strip roadway filling mining method was proposed for safer and more economical mining. FLAC3D software was used to simulate and analyze the roof displacement, pillar stress, and plastic zone distribution under different approach widths. Research results show that the pseudo inclined strip roadway filling mining method can effectively reduce the loss and impoverishment of ore, greatly reduce mining and cutting engineering amount, increase the production capacity of the stope, and achieve separate mining and transportation of different types of minerals. It can be flexibly applied to complex and variable gently inclined ore bodies. After numerical simulation analysis, the optimal approach width for this mine is determined as 5 m or 6 m.

In view of the optimal selection of mining methods in underground metal mines, a game theory-subjective and objective multi-attribute combined weighting model was constructed. Taking the optimal selection of mining methods at the Sijiaying Iron Mine as an example, under the criteria of environment, economy, technology, and safety, 11 indicators closely related to mining methods were selected. The improved analytic hierarchy process (AHP) and CRITIC methods were used to determine the subjective and objective weights of each indicator, respectively. By applying game theory, the subjective and objective weights were integrated to obtain the comprehensive weights for all indicators, providing a basis for the selection of mining methods. The game theory-subjective and objective multi-attribute combined weighting model was used for optimal selection between two alternative mining methods. The comprehensive membership degree of the sub-level open stoping method with subsequent filling is 0.711, while that of the block caving method with subsequent filling is 0.692, with the former being chosen as the optimal scheme. The research results can offer a beneficial reference for decision-making in mining method optimization.

To solve the problem of roof instability or insufficient production capacity caused by unreasonable values of stope structure parameters, an iron ore mine in Hebei Province was selected as the background to optimize the stope structure parameters and analyze their sensitivity. Firstly, a rock mass quality investigation was conducted and the extended Mathews stability chart method with stable probability was used to preliminarily determine the width and length range of the stope. Then, FLAC3D numerical simulation was used to explore the deformation law of the maximum displacement of the stope roof with the variation of structure parameters. Combined with response surface method, a prediction model for the displacement of the stope roof was constructed, and the sensitivity of the single factor affecting the displacement of the stope roof and their interaction relationship were explored. Finally, considering safety and block size, the stope structure parameters were optimized, and industrial experiments were conducted to verify the rationality of the results. The results indicate that the overall rating of the ore body is grade V, and the rock mass quality is very poor. The sensitivity of the roof displacement of the stope to various parameters, from high to low, is as follows: stope width, stope length, and stope height. The optimal stope structure parameters for this ore body are a width of 12 m, a length of 36 m, and a height of 60 m. When using the structure parameters for recovery, the contour of the goaf is relatively flat and stable. The research results can provide theoretical basis for selecting reasonable stope structure parameters and correctly coordinating stope safety and production capacity.

To study the influence of seepage field on the freezing temperature in the loose accumulation rock group of the intake air shaft in the gold mining area in the northern sea area of Sanshan Island, Laizhou City, based on the flow velocity measurement and the material parameters of the rock group, the COMSOL finite element numerical model was established. The intersection time of the three-circle freezing construction of the vertical shaft and the formation time of the freezing curtain were predicted, and the reliability of the design and numerical simulation of the three-circle freezing construction scheme of the vertical shaft was verified by an engineering example. The results show that due to the high flow velocity of coastal groundwater, the intersection line of the inflow surface is shaped like teeth during the freezing process. The low temperature of the freezing pipe has a significant impact on the downstream under the seepage action, and the freezing curtain develops asymmetrically and shifts to the downstream of seepage. The three-circle freezing design reduces the temperature of the shaft excavation area to below the phase transition temperature of −1 ℃ after 18 days of freezing. In the engineering verification, the intersection time and the freezing curtain formation time are 25 d and 36 d, respectively, which are consistent with the numerical simulation results. The research results can provide reference for similar projects.