During the mining process of metal open-pit mines, a large amount of solid wastes such as waste rocks and tailings are discarded. Under the action of wind, sun and rain, harmful substances such as heavy metals in the wastes enter the soil, causing the soil in the mining areas and surrounding areas to be polluted. Therefore, it is of great significance to study the production, migration and enrichment of heavy metal elements in open-pit mine soil to guide the prevention and control of heavy metal pollution in mines. The types of pollution sources, soil properties and the influence of hydraulic action on the migration of pollutants in open-pit mines were introduced, and the measures to improve the risk of soil heavy metal pollution in mining areas were summarized. It points out that further research is of great significance on the influence of soil physical and chemical properties on the migration of heavy metals and establishing corresponding numerical models, and it is necessary to form a comprehensive three-dimensional heavy metal pollution prevention and control system. The study can provide a theoretical support for the control of soil pollution in mining areas.

There is a serious problem of heavy metal compound pollution in lead-zinc mining areas. Hyperspectral remote sensing technology can be used to extract heavy metals absorption characteristic spectra from soil spectral information and achieve inversion of heavy metal contents in the soil of mining areas. Based on hyperspectral data, the heavy metals contents in soil, such as Cd, Pb, As and Hg, were retrieved from the soil of the Silongduo lead-zinc mining area in Xizang. The hyperspectral data from soil samples was collected and various spectral transformations were performed, including first differential (FD), second differential (SD), logarithm of the reciprocal (AT), first differential of logarithm of the reciprocal (AFD), and second differential of logarithm of the reciprocal (ASD). The characteristic bands that are strongly correlated with the measured content of heavy metal were selected and finally four inversion models were established, including stepwise multiple linear regression (SMLR), support vector machine (SVM), artificial neural network (ANN), and random forest (RF). The coefficient of determination(R²)and root mean square error (RMSE) were selected to evaluate the accuracy of the models and the optimal inversion model for each heavy metal was obtained. The research results show that the dimensionality reduction effect and feature band selection interval of different spectral transformation methods are different. Among the five transformations, SD transformation has the best effect and can effectively distinguish feature bands, followed by ASD and AFD transformations. The RF model has the best inversion effect, with a better applicability and inversion accuracy than SMLR, ANN, and SVM. The best inversion model for As is the AT-RF model, the best inversion model for Cd is the SD-RF model, the best inversion model for Pb is the ASD-RF model, and the best inversion model for Hg is the ASD-SMLR model. The average assessment values of Cd, Pb, As, Hg content models of soil exceeded the background value of Xizang soil by 124.2, 89.8, 0.70, 1.24 times, indicating that Cd and Pb were the main pollution factors of the soil in the mine concentration area, accompanied by the combined pollution of As and Hg.

With the increase of mine depth, the heat damage becomes more and more obvious. It is difficult to meet the cooling demand of deep mines only by optimizing ventilation. The key to mine cooling by using refrigeration cycle is to choose a reasonable heat sink (cold source). Taking the demand of heat damage control in a gold mine in Guizhou as the background, based on the concept of energy tunnel, it was proposed to use the filled abandoned roadway as a cold source to receive the heat transferred from the fresh air inlet or the underground working face, so as to achieve the purpose of cooling the underground space. The thermal physical parameters of filling materials of abandoned roadway and surrounding rock were measured, and the cold source model of abandoned roadway was established. The 20-year operation was simulated, and the outlet water temperature, heat transfer power and system energy efficiency under two operating modes and three heat exchange tube layout scenarios were obtained. The results show that only by increasing the number of heat exchange tubes, the technical and economic indicators cannot be significantly improved. The intermittent operation mode can alleviate the heat accumulation of the heat sink and improve the heat transfer intensity of per unit tube length, which is conducive to the long-term stable operation of the system. According to the cooling load of the working face, the scrap power threshold is set, and the total heat storage of the heat sink within the service life is calculated. Combined with the heat transfer intensity of per unit tube length, the feasibility of different application scenarios are compared and evaluated. The research results provide a new idea for the reuse of abandoned mine space and the treatment of underground heat damage.

China's mining industry generally has the problems of high carbon emission intensity and extensive energy consumption. At present, mining is still in the theoretical level of carbon emission accounting, and there is a lack of unified management and analysis of carbon emission in the process of mining production. In view of the current situation of carbon accounting in underground mining, the existing accounting methods were summarized, and the carbon emission prediction and measurement model was constructed by using the whole life cycle assessment method and the carbon emission coefficient method, combined with the mine production management data and process equipment and other parameters. Based on this, the MVC software architecture model was used to build a system platform of carbon emission accounting for underground mining, and the function decomposition and interface design were carried out according to the six main modules of production data entry, prediction model calculation, measured model calculation, data comparison accounting, carbon perspective analysis and basic data management. Through the example application of Chengchao Iron Mine, it is concluded that in addition to high-power and high-energy-consuming process equipment such as lifting and ventilation, transportation, support and pneumatic drilling equipment are all key carbon emission points, and the error between the predicted data and the measured value is less than 10%, which meets the accuracy requirements. It shows that the constructed system can effectively realize the prediction and data analysis of carbon emissions from underground mining. The research results have guiding significance for the subsequent carbon reduction work of the mine.

Flotation wastewater treatment is of great significance to reduce environmental pollution, save water resources and promote the sustainable development of the mining industry. The present situation of treatment technology of flotation wastewater was reviewed, based on the analysis of the source, characteristics and harm of flotation wastewater, the research progress of physical, chemical and biological treatment technology of flotation wastewater was summarized. The results show that the physical methods such as coagulation-flocculation and adsorption have slow processing speed, and the removal effect of complex pollutants such as organic agents is limited. Advanced oxidation technologies such as Fenton method and ozone method are expected to become an important development direction of flotation wastewater treatment in the future because of their simple operation and high efficiency. The microbial method has a significant advantage of no secondary pollution, but it is urgent to solve the problems of long treatment time and difficult adaptation of microorganisms to the environment of flotation wastewater. In the future, different processes can be combined to form a treatment technology system of flotation wastewater for different reuse needs.

The key to prevent water outburst/gusher in coal mine is to clarify the hydraulic relationship between coal measure strata and aquifer, accurately detect the occurrence of abnormal areas, and take preventive measures in time. Based on the geological characteristics of the mining area and the evaluation of water inrush, the experimental system of coal-rock-water coupling occurrence was established to investigate the electric excitation response characteristics and signal attenuation characteristics of the medium under the magnetic field outside the borehole radar. The results show that the height of the water flowing fracture zone of the working face is 56.64 m, which exceeds the height of the water barrier. The working face is threatened by the water of the Changxing Formation aquifer and the goaf, and the risk of water inrush is high. In LCR digital bridge experiment, the dielectric constant of the medium decreases with the increase of frequency. At 100 MHz, the dielectric characteristics of the medium and the peak value of capacitance-dielectric loss(C_p−D)feature have obvious differences, and the signal transmission is stable. The resolution of borehole radar detection profile is increased at 100 MHz, and the imaging is stable. The low-resistivity anomaly area is mainly the boundary of rock strata and the water-bearing anomaly area of the Changxing Formation limestone, and some fracture zones have been found to contain water. The research results are brought into the pre-engineering consideration, and the results of geophysical exploration are further analyzed from the quantitative point of view, which provides some practical reference for similar geological water exploration work.

In response to the current challenges of low accuracy, inefficiency, poor real-time performance, and weak environmental adaptability in ore detection technology, a ore identification system based on Orange Pi was proposed. This system utilized a high-definition camera to capture real-time images of ores and processed image data using the YOLOv4-tiny-tf2 model on the Orange Pi 5B development board to achieve efficient and accurate identification of ore types. The results show that the lightweight YOLOv4-tiny-tf2 model simplifies its structure without sacrificing the accuracy of the model, which is more suitable for deployment on lower-configured devices and has a higher portability. Compared with the traditional artificial visual inspection and chemical analysis methods, the ore identification system based on Orange Pi 5B can identify the ore in real time, and the identification accuracy rate reaches 93.75%, which has high reliability and stability.

To efficiently recover copper from magnetic separation tailings of an iron mine in Anhui, the occurrence states of copper, zinc, and sulfur minerals were investigated, and the key process conditions affecting copper recovery were optimized through flotation experiments. The results show that copper with a grade of 0.10% in magnetic separation tailings is mainly present in the form of chalcopyrite, zinc with a grade of 0.37% is mainly present in the form of sphalerite, and sulfur with a grade of 3.22% is mainly present in pyrite. All minerals are fine-grained disseminated. Employing a mixed flotation-preferential copper flotation process, the optimal reagent combination of condition test is determined as follows: collector PQ-5 dosage of 70 g/t; sphalerite depressant as a combination of 400 g/t sodium sulfide, 500 g/t zinc sulfate, and 400 g/t sodium sulfite; pyrite depressant PZ-1 dosage of 300 g/t. The closed-circuit test adopted a one roughing, three cleaning, and two scavenging process, ultimately obtaining a copper concentrate with a copper grade of 20.85% and a copper recovery of 81.41%. Meanwhile, the removal rates of zinc and sulfur in the copper concentrate reaches 94.12% and 96.30%, respectively, achieving effective separation of copper from other minerals. The research results can provide valuable reference for the efficient recovery of copper from the magnetic separation tailings of this iron mine.

In order to make slag resource utilization and harmless treatment, CaO−MgO−Al₂O₃−SiO₂ (CMAS) slag glass-ceramics were successfully prepared with different additions of cadmium using glass-ceramics preparation technology with solid wastes such as tailings and fly ash as main raw materials. The crystallization characteristics of glass-ceramics with different additions of cadmium were characterized by differential scanning calorimetry (DSC), XRD, SEM, and Raman spectrum. At the same time, the bulk density, flexural strength, thermal expansion coefficient, Vickers hardness and toxicity leaching concentration of glass-ceramics with different additions of cadmium were analyzed. The results show that with the increase of cadmium addition, the full width at half maximum of the crystallization peak gradually decreases, which promotes the crystallization of the glass-ceramics, but the main crystal phase does not change significantly. The related elements in the glass-ceramics are depolymerized due to the addition of cadmium, which changes the microstructure of the glass-ceramics. In addition, the flexural strength, Vickers hardness and bulk density of the glass-ceramics increase with the increase of cadmium slag addition. The results of toxicity leaching test indicate that the maximum leaching concentration of cadmium is 0.030 37 mg/L, which is far lower than the maximum leaching concentration of hazardous waste specified by the state.

The solid waste coal gangue produced in the process of coal mining and washing and the discharge of Pb(Ⅱ) from industrial wastewater will bring great harm to the ecosystem and human health, and it is of great significance to study the efficient removal method of Pb(Ⅱ) and the rational utilization of coal gangue for ecological and environmental protection. A low-cost aminothiol difunctional modified coal gangue (CG-SHNH) composite material was prepared by grafting 3-mercaptopropyl trimethoxysilane (MPTMS) and 3-aminopropyl triethoxysilane (APTES) with coal gangue. The physical and chemical properties of the adsorbed materials were investigated by means of XRD, XRD-EDS, XFR, FTIR, SEM, Zeta potential, and so on. And it is found that new bands appeare at 2 930 cm⁻¹ and 2 560 cm⁻¹, corresponding to C—H and S—H tensile vibrations, respectively, and a new peak appeares at 3 367 cm⁻¹, which is the absorption peak of N—H bonds, indicating that the surface of CG-SHNH is rich in amino and sulfhydryl functional groups. The results of N₂ adsorption-desorption analysis indicate that the average pore size of CG-SHNH increases significantly, from 17.33 nm to 24.54 nm. The study on the adsorption performance of CG-SHNH for Pb(Ⅱ) shows that the optimal adsorption capacity of CG-SHNH for Pb(Ⅱ) is 125 mg/g when the addition amount of CG-SHNH is 1 g/L, the contact time is 20 h, the temperature is 25 ℃, the pH is 6.6, and the initial concentration of Pb(Ⅱ) is 600 mg/L. The adsorption mechanism shows that CG-SHNH amino and sulfhydryl bifunctional groups can synergistically promote the chelation adsorption of Pb(Ⅱ), exhibiting excellent heavy metal ion adsorption ability.