A self-oscillating pulsed jet nozzle can convert a continuous jet into a pulsed jet, which effectively enhances rock-breaking efficiency by inflicting periodic "water hammer" damage on the rock. As the core component for regulating jet morphology, the conventional linear structure of the nozzle oscillation cavity suffers from energy dissipation, thereby constraining jet performance. To address this, a study was conducted to investigate the influence of the cavity diameter ratio (the ratio of the oscillation cavity length L to the upper nozzle diameter d₁) on the pulsed jet performance within the external field, thereby identifying the optimal range for this ratio. From the perspective of flow field structure, the dynamic relationship between the internal low-velocity zone of the cavity and jet performance was analyzed, and Bezier curves were employed to optimize the wall profile of the oscillation cavity. Rock breaking and punching experiments using the self-oscillating pulsed jet nozzle were performed before and after the shape optimization of the oscillation cavity wall to comparatively verify the optimization effect of the oscillation cavity shape of the nozzle. The results indicate that when the cavity diameter ratio is between 5 and 6, the internal low-velocity zone of the oscillation cavity is minimized, yielding optimal jet performance in the external field. For the optimized nozzle, the average velocity and peak velocity of the external field exhibit increases of 16.99% and 16.74%, respectively. Furthermore, compared with the original nozzle, the diameter, depth, and volume of the punching holes generated by the pulsed jet impact on the rock are enlarged by 25.45%, 24.27%, and 18.32%, respectively. These findings demonstrate that the overall performance of the self-oscillating pulsed jet nozzle is effectively upgraded.

Current path planning algorithms for mine cars generally suffer from low search efficiency and excessively long planned paths when navigating complex mining terrain. Developing highly efficient and precise path planning methods has thus become a critical issue requiring urgent resolution. An innovative two-layer transportation path planning scheme was proposed. The upper layer employed the improved A^* algorithm to initially plan the paths between nodes, while the lower layer utilized the improved sparrow search algorithm (ISSA) for overall path optimization. This ensured the minimization of energy consumption and cost for the overall path, aiming to achieve efficient and precise mining transportation path planning. The results show that the two-layer transportation path planning scheme based on the improved A^* algorithm and ISSA not only realizes the minimization of path energy consumption, but also minimizes the path cost, effectively enhancing the efficiency and safety of path planning. In the path planning process, the proposed scheme by the research institute will not be affected by obstacles, there will be no situation of taking a detour, and it can reach the destination along the shortest path. It has excellent obstacle avoidance and shortest path planning capabilities. Moreover, in the three-dimensional topographic map of the mine with complex terrain, it can quickly solve the target function value with lower energy consumption and lower path cost. The shortest transportation distance obtained by the two-layer transportation path planning scheme based on the improved A^* algorithm and ISSA is only 3 125.36 m. The cargo damage cost, transportation cost, and carbon emission cost are 1 028.63 yuan, 3 968.57 yuan, and 335.18 yuan, respectively, and the transportation time is only 1 836.39 s. All these indicators are lower than those of the mine transportation path planning scheme based on the genetic-ant colony reinforcement learning algorithm.

To optimize the antenna layout for mine wireless communication systems, a 3D model of a rectangular roadway measuring 5 m in width and 3.4 m in height was constructed using the Shooting and Bouncing Ray tracing (SBR) method. A multi-scale analysis of power attenuation characteristics in the 0.9 GHz, 2.4 GHz, and 3.5 GHz frequency bands within roadways was conducted across transmission distance, longitudinal cross-section, and spatial distribution. The impact of antenna positioning on wireless transmission was also investigated. The results show that the 0.9 GHz frequency band exhibits superior transmission characteristics compared to the other two bands. The mean longitudinal cross-sectional power at different transmission distances is 6.60-9.17 dBm and 10.49-12.63 dBm higher than that for 2.4 GHz and 3.5 GHz, respectively. The optimum horizontal position for the antenna is within 0.01 to 0.1 m from the roadway wall. When the antenna was deployed flush against the wall (within 0.01 m of the wall), the spatial power distribution exhibites an asymmetric characteristic. The received power in the adjacent wall area on the same side as the transmitting antenna is 1 to 4 dBm higher than on the opposite side. A stable and strong reception signal can be obtained when the height difference between the transmitting and receiving antennas is less than 0.5 m. The research findings may serve as a reference for optimizing base station placement and antenna layout within roadways, thereby facilitating the development and construction of intelligent communication systems for mining operations.

The grades of gold, silver, copper, lead, zinc, sulfur and iron in a low-grade polymetallic sulfide ore in western Yunnan are 1.92 g/t, 41.31 g/t, 0.39%, 1.20%, 0.42%, 9.54% and 34.92% respectively, and the content of harmful element As is 0.22%. The low-grade polymetallic sulfide ore has low grade of valuable elements, complex occurrence state, many kinds of minerals, uneven dissemination size, and difficult comprehensive recovery. The genetic characteristics of the ore, including the composition and relative content of main minerals, the dissemination relationship of the main minerals, grain size and liberation characteristics, as well as the occurrence states of gold, silver, copper, lead, zinc, sulfur and iron, were systematically investigated and determined using chemical analysis and chemical phase analysis. Based on this, the principle process of "copper-lead mixed flotation, copper-lead separation, zinc-sulfur mixed flotation, zinc-sulfur separation, and low-intensity magnetic separation for iron" was proposed. The results of laboratory process verification test show that under the condition of grinding fineness of -0.074 mm accounting for 90%, the concentrates are obtained as follows, copper concentrate with a copper grade of 21.19%, gold grade of 52.40 g/t, silver grade of 558 g/t, and copper recovery of 74.50%; lead concentrate with a lead grade of 74.66%, gold grade of 24.85 g/t, silver grade of 1 730 g/t, and lead recovery of 82.54%; zinc concentrate with a zinc grade of 46.27% and zinc recovery of 76.88%; sulfur concentrate with a sulfur grade of 45.54% and sulfur recovery of 81.91%; as well as magnetite concentrate with an iron grade of 63.47% and iron recovery of 36.87%.

A copper-sulfur ore processing plant in Guangdong employed a "high-alkali copper extraction-weak-acid sulfur extraction" process and reagent system. To address the problems of high on-site alkali consumption, low flotation efficiency, and elevated safety and environmental risks, experimental studies were conducted on ore properties and mineral processing techniques. This led to the identification of a "low-alkali, acid-free" process scheme and based on the ore characteristics, the development of a tailored, low-alkali reagent system for the green and efficient separation of copper-sulfur. Results indicate that a scheme employing B18 to collect copper minerals and CD-S2 to partially replace lime for sulfur suppression, with copper sulfate replacing sulfuric acid for activation, and butyl xanthate for sulfur floation, is effective. The closed-circuit test achieved a copper concentrate with Cu grade of 20.84% and Cu recovery of 88.11%, along with a comprehensive sulfur concentrate with S grade of 46.12% and S recovery of 94.68%. Compared to the "high-alkali-weak-acid" process, the "low-alkali-acid-free" process can increase the copper grade and recovery in copper concentrate by 2.59 percentage points and 1.94 percentage points respectively, while maintaining comparable overall sulfur concentrate indicators. The pH of the roughing pulp in closed-circuit tests decreases from 11 to 8.5, achieving clean and efficient separation and recovery of copper and sulfur in a low-alkali-acid-free environment.

To address the low flotation separation efficiency of chalcopyrite and pyrite, a novel thiol collector (930 agent) was adopted in flotation tests. Its selective adsorption mechanism was revealed by Fourier transform infrared spectroscopy analysis, and its effectiveness was verified through mineral flotation tests. The test results show that the novel environment-friendly and high-efficiency collector 930 agent, obtained by functional group structure reconstruction based on thiol collectors, increases the copper recovery of concentrate by 12.27% and 4.77%, the sulfur recovery of concentrate by 13.84% and 1.99%, and raises the sulfur grade of sulfur concentrate by 3.37% and 3.00% respectively, compared with the traditional collectors ethyl xanthate and butyl xanthate. The use of the new 930 collector optimizes the selectivity of copper-sulfur separation, provides a novel agent scheme with high selectivity and environmental friendliness for sulfide ore flotation separation, and is of great significance for reducing smelting costs and alkaline wastewater discharge.

To investigate the effect of varying magnetization times on the reverse flotation of fine-grained hematite, water, reagents, and slurry were subjected to magnetization treatments of differing durations. By measuring the conductivity and surface tension of the solution, the viscosity of the solution and slurry, and the changes in infrared and Raman spectra of the mineral particle surfaces at different magnetization times, the mechanism by which magnetization time influences the reverse flotation of hematite was revealed. Results indicate that the magnetization effect is optimal at an 8-minute magnetization time. Magnetized water, starch and slurry can enhance hematite recovery rates by 2.3 percentage points, 4.16 percentage points and 3.84 percentage points respectively, whereas magnetized dodecyl amine reduces hematite recovery by 3.56 percentage points. Magnetization increases the solution's electrical conductivity, enhancing the solubility of reagents and the concentration of electrolytes within the solution. It also elevates viscosity, thereby strengthening the inhibitor's efficacy and preventing hematite particles from floating. Furthermore, it reduces the solution's surface tension, facilitating the adhesion of quartz to bubbles and improving the recovery rate in hematite reverse flotation. Infrared spectroscopy analysis indicates that magnetization influences the interaction between the reagent and the mineral surface, altering the amount of reagent adsorbed onto the mineral surface.

To effectively solve the problems of poor selectivity and only being suitable for separation in weakly alkaline environment of traditional cationic collectors used in reverse flotation desilication of phosphate, a novel high-efficiency cationic collector SDTQ suitable for separation in weakly acidic environment was developed. Flotation tests were carried out on a siliceous-magnesian phosphate from Guizhou Province using this collector. The results show that when pH=6 and the SDTQ dosage is 25 mg/L, the recovery of pure quartz mineral is close to 100%, while fluorapatite exhibits no obvious floatability. In the flotation of artificial mixed ore, good separation effect of fluorapatite and quartz is achieved at pH=6 with an SDTQ dosage of 100 mg/L. On this basis, using the magnesium-depleted phosphate concentrate pulp at pH=6 as the research object, the collector dosage condition test was carried out. The optimal SDTQ dosage is determined to be 1.1 kg/t. Under this collector dosage, open-circuit tests were carried out. The separation indexes of P₂O₅ grade 35.38%, P₂O₅ recovery 85.41% and acid-insoluble content 5.53% in phosphate concentrate are obtained. Finally, through the closed-circuit process of one roughing, one cleaning and one scavenging, favorable separation indexes are obtained, with P₂O₅ grade of 35.49%, P₂O₅ recovery of 90.31% and acid-insoluble content of 9.81% in phosphate concentrate. Compared with dodecylamine, SDTQ increases the P₂O₅ grade of phosphate concentrate by 2.05 percentage points and the recovery by 10.02 percentage points. The measurement results of Zeta potential and contact angle show that SDTQ is selectively adsorbed on the quartz surface through electrostatic interaction, and the enhanced hydrophobicity difference between quartz and fluorapatite is the key mechanism to achieve efficient desilication in phosphate reverse flotation. The test results of atomic force microscopy and Fourier transform infrared spectroscopy show that SDTQ collector acts on the quartz surface in the form of physical adsorption through the synergistic effect of quaternary ammonium cationic groups and long-chain alkyl groups. SDTQ collector can improve the grade of phosphate, reduce reagent cost, and has both economic and environmental advantages.

To investigate the motion patterns and separation mechanisms of different magnetic particles in a permanent magnet roller separator during mineral processing, a magnetic force calculation model was established based on the magnetic field gradient and particle specific magnetic susceptibility. The magnetic field distribution of the permanent magnet roller system was simulated using ANSYS Maxwell. The obtained magnetic field vector data were then imported into the EDEM simulation environment via its field management interface. Subsequently, secondary development was performed using the C++ API to extend EDEM's capabilities for simulating particle behavior under magnetic forces. Simulation results indicate that the distribution density of magnetic particles in high-velocity zones is significantly higher than that of intergrowth particles and non-magnetic particles. As particle size increases from 15 mm to 60 mm, the average and the minimum roll-off speeds of the particles show an increasing trend, while the maximum roll-off speed exhibits the opposite behavior. When the magnetic roller speed increases from 10 r/min to 50 r/min, the trajectory spacing among magnetic particles, intergrowth particles, and non-magnetic particles all increase. At a speed of 30 r/min, particle separation performance is optimal. Experimental validation of the coupled simulation method demonstrates that it can realistically simulate the magnetic particle separation process. The research findings provide crucial theoretical foundations and technical support for optimizing such mineral processing technologies.

Aiming at the problem of low separation accuracy when recovering copper and aluminum particles from lithium iron phosphate batteries by wind specific gravity separation method, heavy liquid separation was conducted on three samples: the copper-aluminum mixture obtained after crushing and screening of battery cells from a factory's battery crushing and sorting system, as well as the copper product and aluminum product obtained from air gravity separation. The results show that at a heavy liquid density of 2.95 g/cm³ and a solid-liquid ratio of 0.35 g/mL, the aluminum recovery rates of the copper-aluminum mixture vary with particle size. For particles >0.630 mm, the Al and Cu recovery rates reach 96.99% and 99.72%, respectively; for particles of 0.630-0.104 mm, the corresponding values are 97.62% and 90.02%. The recovery rates of aluminum and copper are 96.44% and 99.83%, respectively. The aluminum recovery rate of particles greater than 0.630 mm reaches 99.66%, and the copper recovery rate reaches 98.52%. The aluminum recovery rate for particles in the 0.630-0.125 mm size range reaches 90.60%, and the copper recovery rate reaches 96.46%. Copper and aluminum can be obtained from raw materials via heavy liquid separation, and separated from raw materials using the same method. The research results provide a basis for the subsequent separation of black powder and metal particles.