With the continuous exploitation of wolframite resources, the raw ore gradually tends to be poor and fine. Flotation has become an effective means to improve the recovery efficiency of fine wolframite. In recent years, study of flotation technology has mainly focused on the development of flotation reagents. Taking the development of wolframite flotation reagents as the starting point, the development of collectors, activators and inhibitors in wolframite flotation was introduced. The combination methods, advantages and disadvantages and indexes of reagents were described in detail. The flotation process mechanism of flotation reagents and the mechanism of solid-drug surface action were analyzed. The results show that the chelating collector has strong selectivity, but the cost of the reagent is high, the manufacturing process is complex and the stability is poor, and there are few reagents that can be applied in actual production. Fatty acid collectors are widely used because of their strong collecting ability and low price, but their selectivity will be reduced, and they are often used in combination with other agents. The collecting performance of arsonic acid and phosphonic acid collectors is better than that of fatty acid collectors, but because of its high price and environmental pollution, it has not been applied in actual industrial production. The combined use of collectors can not only reduce the production cost of mines, but also reduce the use of toxic agents to a certain extent. Highly selective activators and inhibitors can achieve efficient separation of wolframite slime and gangue minerals. According to the existing situation, new reagents with high selectivity, low dosage, environmental protection and non-toxicity should be developed according to different ore properties.

Aiming at the problem of stable driving of mining rehicle in the complex terrain of submarine cobalt-rich crusts, a scheme of four-track all-wheel drive travel mechanism for deep-sea mining vehicles and a terrain-adaptive control method were proposed, and a mechanical model of four-track travel was established. A multi-body dynamics simulation model was built based on Recurdyn software. The characteristics of the four-track travel mechanism, such as straight-line travel, climbing, obstacle-crossing and steering, were analyzed, and laboratory tests and marine tests for the travel mechanism were carried out for verification. The results show that the test results are close to the theoretical calculation values, with the calculation error within 10%. The adaptive control method effectively improves the travel effect of the travel mechanism and reduces the deviation of straight-line travel. When the travel speed is 0.051 m/s, the adoption of vehicle body leveling control can improve the travel stability by 2 to 3 times. However, when the travel speed is 0.198 m/s, the control effect is relatively poor. On the whole, as the travel speed increases, the effect of the adaptive control weakens continuously. The research results can provide references for the research and development of travel technologies and equipment in deep-sea complex terrains.

With the deepening of environmental protection concepts and the continuous advancement of battery technology, the development of new energy vehicles has entered an explosive growth period, and it has also triggered a wave of disposal of retired batteries. In order to cope with the challenge of efficient and green recycling of waste lithium iron phosphate (LFP) batteries, the main literatures on the recycling of lithium iron phosphate batteries at home and abroad in recent years were comprehensively reviewed, and the latest developments of pretreatment, regeneration and repair, pyrometallurgical and wet recycling technologies were systematically introduced. By analyzing and comparing the main characteristics and shortcomings of various recovery technologies, the advantages of wet selective leaching in current recovery practice were pointed out, and the necessity of its development in the future comprehensive recovery of all components and multi-process coordination was emphasized.

To optimize the mechanical strength performance of mine waste rock-tailings cemented backfill, the Box-Behnken design within the response surface methodology (RSM) was used to conduct a three-factor-three-level test. The synergistic effects of waste rock particle size (0 to −5 mm, +5 mm to −10 mm, +10 mm to −15 mm), mass concentration (84%, 86%, 88%), and sand-to-binder ratio (53%, 60%, 67%) on the uniaxial compressive strength of backfill at different curing ages (7 and 28 days) were systematically explored. At the same time, the traditional orthogonal test was introduced to compare the prediction accuracy and efficiency with the RSM. The RSM results reveal that particle size of waste rock predominantly governs the early-stage strength of the backfill, while mass concentration significantly influences the later-stage strength. The synergistic interaction between particle size and mass concentration is the most pronounced, jointly regulating the skeleton stability and interfacial bonding properties of the backfill. After experimental verification, the accuracy (R²) of the backfill strength prediction model obtained based on RSM is 0.994 9 (7 d) and 0.983 7 (28 d), respectively. The corresponding optimal filling material proportion condition are waste rock particle size of +5 mm to −10 mm, mass concentration of 85.5%, and sand-to-binder ratio of 58.6%. The results of the orthogonal experiment indicate that the particle size of waste rock plays a dominant role in the backfill strength in the early and later stages. Research has shown that RSM can effectively analyze the nonlinear coupling relationship of multiple factors, and the prediction accuracy is significantly improved compared to traditional orthogonal experimental methods.

Fiber-reinforced wet-mix shotcrete has excellent properties such as deformation resistance and crack resistance. To evaluate the support performance of fiber-reinforced wet-mix shotcrete, a series of tests were conducted, including uniaxial compressive tests, notched beam flexural toughness tests, and disk flexural tests. The test results indicate that, although the addition of fibers slightly reduces the compressive strength of wet-mix shotcrete, the flexural strength and energy absorption capacity have been significantly enhanced. The roadway support test results shows that the compressive strength of the steel fiber wet-mix shotcrete can reach 25 MPa, the thickness of the spray layer is maintained at 100−150 mm, with a minimal rebound and notable support effectiveness.

In order to explore the potential value of a large amount of safety hazard data in the construction process of intelligent mines, taking a mine in Shandong as an example, comprehensive analysis of its historical safety hazard data from 2014 to 2023 was conducted, and a multidimensional analysis model for mine safety management was constructed. Firstly, a Multi-Layer Perceptron (MLP) was used to construct a personnel, equipment, and environmental classification model for identifying hazards and accidents. Using the Latent Dirichlet Allocation (LDA) topic model, equipment hazards were classified into eight topics of lighting, transportation, support, electrical, firefighting, blasting, ventilation, and miscellaneous. Then, based on the principle of Apriori algorithm, key information was extracted from unstructured hazard text, and the relationship between different hazard features and topics was explored and analyzed. Finally, deep analysis of the data mining results was conducted using a combination of multidimensional analysis and data visualization techniques. The results indicate that equipment related hazards are high-risk areas that require special attention in the safety management of the mine. The lack of support for the roof, potholes on sloping road surfaces, and installation of switch grounding are significant hazard topics and associated rules, and the areas such as S16181 and S18165 are gathering areas for this type of hazard. The multidimensional analysis model constructed by the research can provide a basis for the analysis of mining safety hazards.

The contents of silver (Ag), lead (Pb), zinc (Zn), iron (Fe), manganese (Mn) and sulfur (S) in a polymetallic ore in Heilongjiang are 330.52 g/t, 0.57%, 0.29%, 25.77%, 9.05% and 3.38%, respectively. Due to the carbon content is high, mineral dissemination relationship is complex, as well as Ag, Pb and Zn are partially wrapped in Fe-Mn minerals, it is difficult to guarantee the concentrate grade and recovery rate. In order to realize the comprehensive recovery of valuable components in the ore, the process of Ag−Pb−Zn mixed flotation and Fe-Mn magnetic separation was adopted, and the full process closed-circuit test was carried out. The Ag, Pb and Zn grades of the Ag−Pb−Zn mixed concentrate obtained by the test are 3 010.80 g/t, 5.39% and 2.37%, respectively, and the recovery rates are 83.35%, 89.61% and 77.55%, respectively. The Fe grade and recovery rate of the Fe concentrate are 60.97% and 8.01%, respectively, and the total Fe recovery rate is 71.89%. The Mn grade and recovery rate of Mn concentrate are 18.30% and 76.38%, respectively. The tailings yield of the full process is 50.23%, and the Ag, Pb and Zn grades of the tailings are 35.07 g/t, 0.055% and 0.068%, respectively. By using copper sulfate as an activator and butyl xanthate+ammonium dibutyl dithiophosphate as a collectors in Ag−Pb−Zn mixed flotation, the process has realized the comprehensive recovery of Ag, Pb and Zn with high recovery rates, as well as the effective recovery of Fe and Mn, additionally, the backwater can be reused in production.

The measurement error of the filling batching system is the key factor affecting the quality of the filling body. In order to reveal the effect of the fluctuation in mass fraction and pumping agent dosage caused by the measurement error on the working performance of the filling slurry, based on the cement hydration mechanism and the action principle of the pumping agent, the response surface and variance analysis methods were used to carry out mechanical properties, flow properties and rheological properties tests, and industrial test verification was carried out to determine the optimal mass fraction and pumping agent dosage. The results are concluded as follows. Firstly, when the mass fraction and pumping agent dosage fluctuated within ±1%, the main effect significantly affected the 28 day strength, viscosity, slump, expansion and average viscosity coefficient, and the interaction effect significantly affected the 28 day strength, viscosity and average viscosity coefficient. Secondly, fluctuations in mass fraction and pumping agent dosage can cause changes in the proportion of free water in the filling slurry, thereby affecting the working performance of the filling slurry. Finality, it is suggested that the fluctuation range of the mass fraction of the mine should be kept between 78% and 79%, and the fluctuation range of the pumping agent dosage should be kept between 1% and 2%. The research results can provide a theoretical basis for the construction of filling batching systems and the accuracy calibration of batching equipment.

In order to realize the safe and efficient mining of metal mines in the surface protection area, taking the mining of inclined orebodies under slope in Paishanlou Gold Mine as the engineering background, the roof caving characteristics, stability conditions of caving arch and its control and utilization technology in the goaf of inclined orebodies were systematically studied. It was analyzed and concluded that the inclined orebodies in Paishanlou Gold Mine conform to the characteristics of the arch caving model, and the mathematical relationships between the critical caving span and caving height of the inclined orebodies under slope were established. A goaf caving process control scheme with the subarea mining model as the core was proposed, and the subarea open-stope mining with subsequent centralized filling mining technology was developed. The results of on-site practice show that after adopting this mining technology, the mining cost is decreased by 26.8 yuan/t, the production capacity is increased by 20%, the ore loss rate is decreased by 1.5%, the dilution rate is decreased by 3%, and the mined metal quantity is increased by 427.5 kg. This method not only meets the surface protection requirements of Paishanlou Gold Mine, but also achieves the goals of low-cost, safe and efficient mining. The research results can provide technical references for the mining of low-grade orebodies in surface protection areas.

In the second-step mining of open stoping with subsequent filling mining method, the blasting vibration has significant influence on the stability of the artificial pillar formed after the cement filling in the first-step stope. Based on the background of mining in the transition from open-pit to underground in Sijiaying Iron Mine, a 3D geological model and a numerical calculation model of stope were established by using the FLAC numerical simulation method. And three mining sequences of the second-step stope in the mining panel were studied, including “from one side to the other side” “from the center to both sides” and “from two sides to the center”. When the distance between the blasting hole and the backfill was 1.0 m and 1.5 m respectively, the characteristics of the effect of blasting on the stability of the artificial pillar were obtained, and the strength demand of the backfill body was inverted. The results are concluded as follows. Firstly, when the peak pressure of the blasting load is 15 MPa, with the increase in the distance from the hole to the backfill, the maximum principal stress of the backfill in the first-step stope decreases. The concentrated stress and plastic failure range in the backfill under the “from two sides to the center” mining sequence are the least, which is the most favorable to the stability of the backfill. Secondly, when the mining sequence of the second-step stope is “from two sides to the center”, the longer the distance between the blasting hole and the backfill, the smaller the plastic zone in the backfill, which is more favorable to the stability of the backfill. Meanwhile, the larger the distribution range of the shear plastic zone formed in the two-step mining ore body, the more conducive to the carving of the two-step stope. Thirdly, the strength of cemented backfill prepared by cementing powder and unclassified tailings with a ratio of1:6can meet the stability requirements of artificial pillars.