Based on the theory of synergistic mining, the technical challenges such as handling hidden danger in goaf, recycling hidden trouble resources, and ensuring safe and efficient mining of deep ore bodies have been solved for the difficult-to-mine ore bodies in a tungsten mine in southern Jiangxi Province. Four innovative mining designs were proposed, including changing the mining method from the empty-field method to the caving method, taking hidden trouble resources as cover rock layers for deep mining, using the goaf as a free blasting space for cutting grooves and cushion layers, as well as synergistic applying shallow and medium-deep hole blasting technologies. On this basis, the mining design and application of the segmented rock excavation stage caving method were carried out. The results of mining practice show that the segmented rock excavation stage caving method is suitable for dense vein mining. Compared with the original shallow hole shrinkage method, the mining loss rate of this mining method is reduced from 22% to 3%−5%, the daily production capacity of the stope is increased from 65 t to 260 t, the unit consumption of explosives is reduced from 1.18 kg/t to 0.57 kg/t, and the cost per ton of ore is reduced from 65.54 yuan to 33.26 yuan. It is indicated that the theory of synergistic mining has a significant application value in the mining of dense ore bodies in tungsten mines. The research results provide a technical solution that can be used as a reference for dealing with similar problems in mines.

With the gradual reduction of shallow mining resources, mining is moving deeper and deeper. In order to solve the problems of difficult control of the stability of the surrounding rocks and increased support costs in large-section chamber in deep shaft, and to ensure the stable operation of the 941 m mixing plant chambers group, researches on the stability control of the surrounding rocks in large-section chambers was carried out. Multiple technical methods such as laboratory testing, numerical simulation, and field monitoring were adopted. Through comparative analysis, a reasonable construction process and support design were optimized. It is found that when the excavation of the chambers is carried out in the order of batching machine chamber, mixer chamber, and cement silo chamber, the stability of the surrounding pressure is the best. Then, an orthogonal design experiment was used to obtain the optimal support parameters as a spacing of 2 m×2 m among anchor rods, a length of 6 m for anchor cables, and a thickness of 600 mm for concrete lining. A joint support scheme consisting of anchor mesh spraying + grouting anchor rods for initial support and cast-in-place reinforced concrete + anchor cables was proposed. The on-site support results show that the deformation of the surrounding rocks is effectively controlled.

To investigate the effect of vertical isolation columns on the stability of surrounding rock during the deep mining of gently inclined thick ore bodies, a numerical simulation method was used to compare and analyze the settlement, stress, and plastic zone changes of surrounding rocks under four different schemes for a deep mining project of an iron mine in Shandong. The optimization ratio of vertical isolation columns per unit volume was proposed, and the scheme was optimized on this basis. The results indicate that the volume and position of vertical isolation columns in the deep mining process of gently inclined thick ore bodies have a decisive impact on their optimization effect. The optimal scheme is to leave a vertical isolation column with a width of 20 m and a thickness of 41 m on the 8^# vertical survey line where the settlement peak is generated (Scheme 4), which generates the maximum unit volume optimization ratio of settlement peak, stress peak, and plastic zone. Compared to Scheme 2, Scheme 4 can ensure the stability of the surrounding rocks more effectively. Compared to Scheme 3, Scheme 4 can extract an additional 461 700 tons of iron ore and 272 403 tons of refined iron ore powder, increasing the net profit of the enterprise by about 54.48 million yuan and increasing the net profit income by about 11.20%. The research results can provide some reference for the optimization and application of vertical isolation column retention schemes in similar mines.

Tieshanlong Tungsten Industry Huangsha mining area have the problems of low mechanization level, large quantity of mining preparation and cutting engineering, high labor intensity and large dilution loss rate for original mining technology. In order to solve these problems and improve the mechanization degree and ore utilization rate, according to the development experience of medium-diameter long holes in similar mines, combined with the grooving process of medium-long holes, the coordinated and efficient caving of upward medium-long hole and downward medium-diameter long hole was realized. The medium diameter long hole stage subsequent caving method was developed to mine steeply inclined thin ore body, and representative test blocks were selected for industrial tests. The industrial test results show that compared with the sublevel drilling stage caving method, the medium-diameter long hole stage subsequent caving method reduces the explosive unit consumption by 36.5%, and reduces the loss rate and dilution rate by 60% and 16.8%, respectively. The year-on-year ore volume and WO₃ metal extraction volume increase by 16.7% and 19.0% respectively, and the net profit increases by 729 500 yuan. The results can confirm the significant economic and social benefits of the mining technology of steeply inclined thin ore body, and provide a feasible scheme for long hole blasting mining of steeply inclined thin ore body.

Aiming at the problems faced by the selection of mining methods in the process of open-pit to underground mining in Sijiaying Iron Mine, based on the complex deposit occurrence characteristics of the mining area and the mining technical conditions of the mining surface environment, the stage open-stope subsequent filling mining method and the sublevel open-stope subsequent filling mining method were proposed, and the traditional staggered arrangement of ore transportation was optimized. The results show that the mining method of combined mining of scraper and pit truck in stage can effectively shorten the transportation distance of scraper and improve the transportation efficiency. When the stage height of the optimized mining method is 60 m, the height of the chute in the mining area is reduced by 30 m, and the number of chutes in the panel area is reduced from 6 to 2, which reduces the amount of preparation work and reduces the mining cost. The key problems that should be paid attention to in the selection and implementation of mining methods in this mining area are pointed out, in order to provide a guidance for the open-pit to underground mining work in Sijiaying Iron Mine.

The development and utilization of mineral resources not only provides a material basis for the development of the national economy, but also a key “battlefield” for carbon emission reduction under the “dual carbon” goals. In order to realize the low-carbon development of mines, based on the previous evaluation indexes of mining scheme optimization, the carbon performance related indexes were introduced, and the weighted grey relational mining scheme optimization model considering carbon performance was constructed. Taking a mine in China as an example, in addition to safety, economic and technical indicators, carbon performance indicators such as average carbon performance were introduced. The weight of each index was comprehensively determined using game theory, and the four mining schemes of stage room subsequent filling mining, open-pit stratified stepped mining, open-pit stratified stepped mining (35%) and stage room subsequent filling combined mining, open-pit stratified stepped mining (60%) and stage room subsequent filling combined mining were evaluated. Finally, it is determined that open-pit stratified stepped mining is the optimal scheme. Compared with the optimization results without considering carbon performance, the introduction of carbon performance index makes the weighted grey relational grade of each scheme change, which proves that it is of great significance to consider carbon performance index under the “dual carbon” goals, which meets the requirements of developing green mining and can provide reference for mining scheme optimization of mines under the “dual carbon” goals.

To address the issues of short setting time, poor water resistance and inadequate strength when β-hemihydrate phosphogypsum (β-HPG) is used as backfill cementing materials, two industrial solid wastes, carbide slag and silica fume were introduced. The effects of these wastes on the workability, water resistance, and strength of β-HPG were analyzed. The microstructure and pore structure of the modified β-HPG were investigated by SEM. Additionally, the environmental behavior, cost, and carbon emissions of the modified β-HPG were evaluated. The results indicate that the combined use of carbide slag and silica fume significantly extends the setting time of β-HPG slurry and enhances its fluidity. After modification, the compressive strength of β-HPG backfill is substantially increased, reaching a 28-day strength value of 36.6 MPa, with a reduced water absorption rate of 2.7% and an elevated softening coefficient of 0.885. The incorporation of silica fume and carbide slag can improve the micromorphology and pore structure of β-HPG backfill. The generated calcium silicate hydrate, a hydraulic hydration product, enhances the compactness of backfill. Carbide slag and silica fume effectively neutralize residual acids in the β-HPG and immobilize phosphorus and heavy metal elements within the hardened body. When the content of carbide slag is 10% and the content of silica fume is 15%−20%, the β-HPG cementing material exhibits favorable economic and environmental benefits.

Aiming at the problem of large solid waste reserves and high processing costs in Western Mining Group Co., Ltd., in order to achieve the reuse of solid waste and reduce the filling cost of mines, Xitieshan and Bolun Mining were selected as test objects. Through indoor and on-site industrial tests, researches were conducted on the proportion and application of filling cementitious materials based on industrial metallurgical solid waste replacing the cement. The results show that Xitieshan uses the new type of solid waste based cementitious material to fill the first and second step mining stope of the mine. The 28-day strength of filling under the two proportioning schemes is 2.5 MPa and 1.1 MPa, respectively. The annual consumption of solid waste is 14 625 t, saving the filling costs of 2.036 1 million yuan. Bolun Mining adopts the new formula to treat the filling layer, and 28-day strength of the filling body is 0.99 MPa. The annual consumption of solid waste is 5 623 t, increasing the filling cost by 43 240 yuan. Through the utilization of solid waste resources, Western Mining Group Co., Ltd. can process 20 248 t of solid waste throughout the year, saving the filling costs of 1.603 7 million yuan.

In order to study the mechanical properties and optimal ratio of carbon nanotube modified superfine cement-based grouting materials, carbon nanotubes, superfine cement, dispersant, defoamator and polyacrylate emulsion were used as raw materials based on three-factor and four-level orthogonal test. The water-cement ratio and the content of carbon nanotubes and polyacrylate emulsion were used as control factors. The viscosity, fluidity, setting time, uniaxial compressive strength and elastic modulus of the grouting slurry were tested. The influence of each factor on each index was determined through range analysis and variance analysis. The uniaxial compressive strength and elastic modulus were selected as the index for coupling, and the coupling value was analyzed by range, variance and multivariate linear regression analysis to obtain the optimal ratio and verify it. The results show that the uniaxial compressive strength and elastic modulus of the test block decrease with the increase of the water-cement ratio. With the increase of carbon nanotube content, the uniaxial compressive strength of the test block increases first and then decreases, and the elastic modulus shows a trend of increasing first, then decreasing and then increasing again. With the increase of polyacrylate emulsion content, the uniaxial compressive strength of the test block increases first and then decreases, and the elastic modulus shows a decreasing trend. After the uniaxial compressive strength and elastic modulus of the test block are normalized, the weight of 0.6:0.4 is added and coupled, and the optimal ratio of grouting materials is obtained by range and variance analysis. Through multivariate linear regression analysis and laboratory test verification, the optimal ratio is water-cement ratio of 0.6, carbon nanotubes content of 0.4%, polyacrylate emulsion content of 2.5%. The research results can provide a reference for the optimal ratio of carbon nanotube-modified superfine cement-based grouting materials.

In order to solve the problem of low comprehensive utilization rate of circulating fluidized bed fly ash (CFBFA), coal mine backfill materials were prepared by adding a small amount of cement with CFBFA as the main raw material. The differences in physical and chemical properties between CFBFA and fly ash were compared. On this basis, the control variable method was used to explore the effects of mass concentration, cement dosage and synergist dosage on the fluidity, bleeding rate and compressive strength of backfill materials. In addition, the optimal mix proportion was selected and engineering test was carried out based on a coal mine filling project in Shanxi. The experimental results show that the CFBFA requires a large amount of water and has a high activity. The mass concentration and cement dosage are the key factors affecting the performance of the backfill materials. The higher the mass concentration, the worse the flowability of the filling slurry, the lower the bleeding rate, and the higher the strength of the filling body. The higher the cement dosage, the better the flowability and bleeding rate of the filling slurry, and the higher the strength of the filling body. Without the addition of synergist, the mass concentration is below 0.555, and the cement dosage is 200 kg/m³, the filling slurry meets the design requirements of flowability no more than 20 s and 28 day compressive strength no less than 3.0 MPa. However, the bleeding rate is greater than 2%, which does not meet the design requirements. The synergist can significantly improve the flowability of the filling slurry, reduce the bleeding rate, and reduce the cement dosage by up to 90 kg/m³. The suitable dosage of synergist is 5.0 kg/m³. Engineering tests have shown that the addition of synergists significantly improves the mixability and pumpability of the filling slurry. The flowability, bleeding rate, and compressive strength of the filling material prepared on site with a mass concentration of 0.595, cement dosage of 120 kg/m³, and synergist dosage of 5.0 kg/m³ can meet the engineering design requirements.

To address the challenges of selecting suitable tailings thickening devices for domestic mines due to the diversity of available options, a thickening device optimization method based on the AHP-TOPSIS evaluation model was proposed. Based on the actual filling situation of a certain polymetallic mine, 13 evaluation indicators were selected from aspects such as economy, site conditions, and technology. Three thickening device schemes, including vertical sand silo, deep cone thickener, and paste storage thickener, were comprehensively evaluated and optimized through expert scoring. By calculation and analysis, the comprehensive superiority of the three schemes is found to be 49.51%, 17.42% and 80.11%, respectively. Therefore, the paste storage thickener scheme is determined to be the best scheme. The result is consistent with the actual application situation on site in a certain polymetallic mine, which adopts a filling process based on paste storage thickener. The tailings processing capacity of a single paste storage thickener exceeds 100 t/h, and the tailings storage capacity exceeds 1 600 t. The highest bottom flow mass concentration of the thickener reaches 74%, with a good filling effect. This evaluation model can provide a new method for optimal selection of tailings thickening devices.

In order to clearly present the development process of slurry transportation and comprehensively analyze the key research points related to pipeline transportation in different stages, CiteSpace software was used to conduct co-occurrence analysis and cluster analysis on 494 articles included in the China National Knowledge Infrastructure (CNKI) literature database from 2006 to 2023. The study reveals the following findings. Firstly, the overall trend of changes in the number of publications presents an M-shape, which can be divided into a preliminary exploration period, an efficient growth period, and a stable development period according to the chronological order. Secondly, the research subjects present a distribution of stars around some experts, and there are limitations in the research perspective. Thirdly, the research contents focus on three aspects, including material preparation, transportation technology, and mining filling. The slurry ratio has expanded from focusing on the particle size distribution of tailings to the application of additives, enhancing the integration of various disciplines. Therefore, future efforts could involve strengthening the core position of relevant mining research institutions, attaching importance to cross institutional collaboration and communication, expanding the research group, refining the research scope of pipeline transportation, strengthening the research on filling materials, deepening the depressurization treatment of deep well transportation, and trying to integrate non Newtonian fluid research methods, so as to enrich the research on filling pipeline transportation in the domestic academic community.

In order to study the subsidence law of surface road engineering under the overlapping occurrence conditions of quicksand layer and goaf, taking the reconstruction and expansion project of S342 provincial road above the goaf of Dangyang gypsum mine, FLAC3D was used to study the distribution law of surface displacement under the conditions of quicksand layer, goaf and their overlapping occurrence. The influences of quicksand layer migration and goaf on the stability of surface road sections were evaluated, and a goaf treatment plan was proposed. The research results indicate that under the action of quicksand layer migration and goaf, the surface subsidence gradually decreases from the center of the goaf to the surrounding areas, and the peak subsidence is concentrated in the range of K5+617 to K5+717. The displacement and settlement in the central area of the road centerline are relatively large, showing a pattern of first increasing and then decreasing from west to east. The settlement on the north and south sides is relatively small, with the maximum surface settlement of the north, middle, and south lines of the road being 69 mm, 167 mm, and 31 mm, respectively. As the distance from the surface increases, the displacement of the overlying rock above the quicksand layer shows a decreasing trend in the central area (within a range of 100 m from K5+630 to K5+730), while the displacement in other areas shows an increasing trend. Therefore, the range of surface rock movement under the action of the goaf at the quicksand layer is defined as 100 m. The research results can provide theoretical basis for road expansion projects under the conditions of quicksand layer occurrence.

To address the issues of instability, difficulty in support, and high support costs during the excavation of trapezoidal roadways, a support scheme for the roadway of 105 working face was proposed using theoretical analysis and numerical simulation methods, with a research background in a certain mine in Toksun. The support effect was verified using measured data. The research results indicate that under the existing support conditions, the mining pressure behavior of the 104 working face roadway is not obvious, the surrounding rock stability is stable, and there is no significant delamination phenomenon. On this basis, support scheme can be provided to the 105 working face. Compared with the theoretical analysis values, there is a certain optimization space for the existing support scheme, which can be optimized for design. The optimized support scheme has reduced the control strength of roof and two sides of the roadway, but the support cost has decreased by 32.5%. On-site application shows that during the roadway excavation, the deformation of the roof, the low side and the high side is relatively small, the maximum displacement are 19.6 mm, 21.2 mm, and 26.8 mm, respectively. During the mining period of the working face, the roadway and surrounding rocks of the working face are relatively stable, with no occurrence of high-energy microseismic events. The optimized support scheme can meet the safety requirements of roadway excavation and mining of the working face.

Aiming at the problems of surrounding rock softening, failure of original support mode and roadway collapse in the process of excavation in the contact zone of north and south edge of a copper mine at the level of −400 m, the strength of engineering rock mass was determined by rock mechanics characteristic test, and the failure reason of original support was analyzed. FLAC3D numerical simulation software was used to explore the reasonable support parameters and support principle of prestressed anchor bolt, and the control effect of different support schemes on surrounding rock was compared. On this basis, a joint support scheme with anchor bolt spacing of 0.9 m, pre-tightening force of 90 kN and sprayed concrete thickness of 100 mm was proposed. The numerical simulation results show that the scheme can effectively reduce the plastic zone volume of surrounding rock, and control the roof subsidence and the total amount of two-side convergence of roadway within 21 mm and 19 mm respectively, which are reduced by 44.9% and 56.2% respectively compared with no support, and the support effect is good. The field application results show that the deformation of the roadway tends to be stable after 42 days. On the 91 st day, the roof subsidence is 28.74 mm, and total amount of two-side convergence is 22.32 mm. The scheme can meet the needs of mine safety production. It is reasonable and feasible to design and optimize the support parameters of prestressed anchor bolt in soft rock roadway based on FLAC3D.

Pre-drainage of bedding boreholes before mining is one of the main methods for coal seam outburst elimination in working face. However, most of the outburst coal seams in China have low permeability, resulting in unsatisfactory gas drainage effect, which seriously limits the implementation of this technical measure. In view of the extraction conditions of bedding boreholes in 15111 working face of Sijiazhuang Company, the equipment system and process flow of pressure relief and permeability enhancement for mechanical cavitation of bedding boreholes were put forward. The variation characteristics of coal seam stress and gas content around the mechanical cavitation boreholes were studied, and the influence of the diameter of the cavitation borehole on the pressure relief and permeability enhancement of the coal seam was revealed, and the process parameters of the mechanical cavitation borehole in the 15111 working face were determined. On this basis, the industrial test of mechanical cavitation pressure relief and permeability enhancement in the return airway of 15111 working face was carried out. The results show that the mechanical cavitation of bedding boreholes increases the exposed area and pressure relief range of coal around the borehole, and improves the influence radius of borehole gas extraction. The gas extraction amount of mechanical cavitation is 8.06 times that of ordinary bedding boreholes, and the volume fraction of gas extraction is 153.4% higher than that of ordinary bedding boreholes, and the effect of permeability enhancement is remarkable. The research results provide an empirical reference for regional outburst prevention in mines with similar conditions.

The stress concentration of the roof and the solid coal side will be caused by the untimely collapse of the lateral hard roof in the gob-side roadway, which poses a major threat to the safety of the working face, and the blasting method is often used to weaken it. Taking the gob-side roadway of a working face as the background, the relationships among blasting angle, blasting height and pressure relief effect of the hard roof in the gob-side roadway were studied by means of theoretical analysis, numerical simulation and field practice. The results show that the fracture position on the goaf side is the most conducive to maintaining the stability of roadway surrounding rock during the blasting of gob-side roadway. The blasting angle should be higher than the breaking angle formed when the key stratum is broken, and the roof pressure above the coal pillar after blasting should be avoided. In the range of reasonable blasting angle, with the increase of blasting angle, the pressure relief effect is improved. When the blasting height reaches the top of the combined sub-key stratum, a better pressure relief effect can be achieved. The field engineering practice shows that under the condition of reasonable parameters, the implementation of strike blasting on the roof of gob-side roadway can effectively reduce the impact risk and ensure the safe production of working face. The research results can provide theoretical and engineering basis for mines with similar conditions.

In order to explore the effect of high temperature and water cooling on the dynamic compressive mechanical properties of porous sandstone, XRD and SEM tests were carried out on natural condition and high temperature-water cooled sandstone specimens at 200 ℃, 400 ℃, 600 ℃, 800 ℃ and 1000 ℃. The impact compression test was carried out by SHPB test device, and the high temperature-natural cooling condition was added as a comparison. The results show that the natural sandstone structure is dense, and the main mineral components are calcite, dolomite and quartz. After high temperature-water cooling treatment, calcite and dolomite are gradually decomposed into calcium oxide, calcium hydroxide is formed in water, and the section is covered with micron-sized particles. With the increase of the action temperature, the color of the specimens gradually changes from gray to brown, their volume expands, and their mass, density and longitudinal wave velocity decrease. The dynamic stress-strain curves of the specimens after different high temperature-water cooling treatments are similar, which are divided into three stages, including elasticity, plasticity and failure. The dynamic compressive strength is negatively correlated with the action temperature, and the dynamic strain and average strain rate are positively correlated with the action temperature. With the increase of the action temperature, the impact crushing degree of the specimens is aggravated, and the damage is changed from several fragments to powder. Compared with the high temperature-natural cooling porous sandstone specimens, the dynamic compressive strength and average particle size of the high temperature-water cooling porous sandstone specimens decrease, and the dynamic strain and average strain rate increase. The high temperature-water cooling effect causes the internal structure damage of the porous sandstone specimens. The higher the temperature, the more serious the structural damage of the specimens and the more obvious the dynamic characteristic decline.

In the process of open-pit mine production, mining disturbance can cause different degrees of damage to different areas of surrounding rock, and ultimately lead to changes in the mechanical properties of surrounding rock. In order to explore the influence of different initial damage levels on the mechanical properties and acoustic emission characteristics of sandstone, the characteristic stress value of sandstone was determined by analyzing the acoustic emission impact parameters during the loading process of sandstone samples, and the uniaxial compression test of sandstone with four different initial damage levels was carried out with acoustic emission monitoring system. The results show that the initial damage has a significant effect on the mechanical properties of the rock. With the increase of the initial damage degree, the compressive strength of the rock sample decreases by 33.6%, the elastic modulus decreases by 43.4%, the Poisson's ratio decreases by 64%, and the peak strain point gradually moves backward. The acoustic emission characteristic signals of sandstone with different initial damage levels are in good agreement with the stress-strain curves. With the increase of initial damage level, the sudden increase of local acoustic emission signals is obvious. With the increase of damage level, the crack failure mode of rock changed from tensile failure of non-destructive rock samples to tensile-shear mixed failure.

In order to study the influence of different inclination angles of prefabricated cracks on the mechanical properties and acoustic emission characteristics of rock and the crack expansion mechanism and rupture mode in the process of rock rupture, the Brazilian disc test was carried out by prefabricating disc specimens with different inclination cracks. The acoustic emission technique and the extended finite element method were used to observe and analyze the rupture evolution law of rock under different inclination cracks. The results show that with the increase of inclination angle, the crack initiation position shifts from the tip of prefabricated crack to the middle, and the parameters such as rock initiation load and peak load decrease first and then increase. The analysis results of acoustic emission parameters show that the specimens show various failure modes: the specimens with medium inclination angle mainly occur shear-tensile failure, while the specimens with higher or lower inclination angle mainly occur tensile splitting failure. The cumulative ringing count, cumulative amplitude, cumulative energy and bearing capacity of acoustic emission are consistent with the change trend of prefabricated crack inclination angles. The numerical simulation results are consistent with the laboratory test results, which confirms the effectiveness of the numerical simulation method in predicting rock crack expansion. The research results are helpful to predict and control the rupture behavior of rock mass in mining, tunnel excavation and other fields in engineering operations, and provide an effective reference for solving engineering safety problems in the industry.

Drainage well is an important safety facility in tailings pond, its stability is related to the safety of tailings pond. Based on the similarity principle, the dynamic response characteristics and variation law of the drainage wells in tailings pond under different seismic accelerations and different buried depths were systematically studied by shaking table test. The results show that when the peak seismic acceleration increases from 0.315g to 1.5g, the acceleration amplification coefficient in the drainage wellbore increases first and then decreases, and the well wall gradually changes from elasticity to elastoplasticity, and the stiffness gradually decays. Under the action of 1.5g peak seismic acceleration, the maximum relative displacement of the drainage well under the full-buried condition is 0.967 mm, which is much smaller than that under the non-buried condition of 5.295 mm, indicating that under the action of seismic, the tailings around the drainage well play a stabilizing role in the drainage wellbore, and the seismic performance of the drainage well is improved. In the process of increasing the peak seismic acceleration from 0.315g to 1.5g, the first-order frequency of the drainage well under the non-buried, semi-buried and full-buried conditions decreases by 29.17%, 27.05% and 22.74%, respectively compared with the initial natural frequency, and the stiffness of the drainage well degrades fastest under the non-buried condition. Under the action of seismic, the strain peaks at different positions in the wellbore are positively correlated with the peak seismic acceleration. The maximum strain value appears at the bottom of the drainage well, indicating that it is most vulnerable to vibration damage. The seismic performance of the bottom of the drainage well should be enhanced in the design.

Abandoned open-pit mine has caused serious damage to the ecological environment of the mining area and its surrounding areas, causing a series of problems such as geological disasters, soil erosion and landscape destruction. The ecological restoration and management of abandoned open-pit mine is not only an effective means to build green mines, but also an important way to promote the sustainable development of resource-based cities. Taking a stone mining area in Chifeng City as the research background, the damage status, existing problems and hazards of abandoned open-pit mine in this area were analyzed, and the planning ideas and management modes suitable for this area were put forward. The seven project deployments and corresponding main technical measures involved in the project implementation process were discussed in detail. The results show that the management technology of abandoned open-pit mine is difficult and the success rate of ecological restoration is low. Especially, the exposed slope and rock wall area need to increase the depth of research and management. There are various management modes for abandoned open-pit mines. It is necessary to select one or more suitable combination modes according to their site conditions and influencing factors, and connect them with local planning at all levels. The management of abandoned open-pit mine involves many treatment objectives such as mine, waste dump, slope and soil field. Its management is a complex system engineering. In planning and design, all factors should be taken into account to avoid blind management.

In response to the problem of large computation and slow detection speed of the current pedestrian detection algorithm in underground mines, a lightweight underground pedestrian detection model named MBE-YOLO was proposed based on YOLOv8n. Firstly, a lighter neck structure was designed based on the weighted bidirectional feature pyramid network, with the goal of efficiently fusing multi-scale information. Secondly, the detection head of the original network was redesigned using shared convolution, and the phantom convolution was introduced to obtain rich and effective feature representations, thus solving the problem of the huge number of parameters in the original detection head. Finally, considering the impact of lightweight model on accuracy, a lightweight hybrid local channel attention mechanism was added, which adaptively adjusts the importance of different regions at the global and local levels to improve accuracy. Experimental results show that compared with the benchmark model YOLOv8n, the mAP@0.5:0.95 of MBE-YOLO model is improved by 0.2 percentage points, the computational cost is reduced by 44%, the FPS is increased by 4.3 frames/s, the number of parameters is reduced by 46%, and the model size is reduced by 43%. Compared with the five mainstream models, this model has significant advantages in detection accuracy and lightweight, making it more suitable for scenarios that require real-time detection.

Aiming at the problems of low efficiency and difficulty in applying traditional fire detection algorithms to embedded devices with limited resources, a lightweight fire detection algorithm based on improved YOLOv8n was proposed. Firstly, in order to greatly reduce the number of model parameters, the C2f module in the YOLOv8n model was changed to the C2fGhost module. Secondly, in order to prevent the loss of important features after the lightweight of the model, strengthen the feature extraction ability and reduce the interference of irrelevant information in the image, the EMA attention mechanism was added to the Backbone part of the YOLOv8n model. Finally, in order to improve the generalization ability of the model, the CIoU loss function in the YOLOv8n model was replaced by WIoU. The experimental results show that the parameters of the improved model decrease by 30.1%, mAP50−95 increases by 0.6 percentage points, and the accuracy rate decreases by only 0.2 percentage points. The improved model can detect the underground fire in real time and efficiently, and the detection algorithm has reference value for mine safety management.

In response to the call of Zhejiang Province to comprehensively promote the digital construction of mines, it is committed to realizing the digital transformation and upgrading of mines and promoting the high-quality development of enterprises. Aiming at the system construction requirements of basic digitization in small and medium-sized open-pit mines, modern information technologies such as real three-dimensional, digital twin, the Internet of Things and artificial intelligence were introduced. The system architecture, key technologies and core modules were deeply analyzed and studied. A mine basic digital management system with cross-temporal, full-cycle and multi-domain data fusion was constructed and applied in many small and medium-sized open-pit mines in Linhai City and Wenling City, Zhejiang Province. Its powerful data fusion ability and intelligent management level have promoted the transformation of mining enterprises from "fragmented" management to "integrated" management, realized the transformation of data resources to data assets, and have guided the transformation of enterprises from traditional thinking to modern system thinking. At the same time, it also provides a reference for the digital and intelligent upgrading of small and medium-sized mines in China.

Mineral resources are an important material foundation for human survival and development. To strengthen the research on regulatory technology for cross-border mining in open-pit mines, high-resolution remote sensing technology was proposed for dynamic monitoring of cross-border mining activities. Three periods of high-resolution remote sensing images were selected, the change information of cross-border mining patterns in open-pit mines with provincial and municipal certification in Xiangtan City was extracted, and remote sensing dynamic monitoring research was conducted on cross-border mining in open-pit mines. A remote sensing interpretation marker library was established for the development of open-pit mines in the research area, a relatively complete set of dynamic monitoring technology methods was explored for cross-border mining in open-pit mines. The accuracy of suspected cross-border mining and mining development of the map spot accounts for 100% and 90.3%, respectively. It is found that, from 2016 to 2020, the number, map spots, and total area of cross-border open-pit mines with provincial and municipal certification in Xiangtan City show an overall decreasing trend. The research results indicate that high-resolution remote sensing technology has a strong practicality and high accuracy in the dynamic monitoring of cross-border mining in open-pit mines, and can effectively monitor the dynamic changes of cross-border mining. The research results can provide a technical support for the dynamic monitoring of cross-border mining in open-pit mines in Xiangtan City.

In order to solve the problems of low efficiency, high labor cost, and inability to meet the large-scale drilling requirements of traditional RTK-line hole layout methods, the application of UAV-LiDAR technology in open-pit mines was explored. Taking the Southern Open-pit Coal Mine as the research background, comparative experiments were conducted with traditional RTK-line hole layout method in terms of layout error, operational efficiency, environmental adaptability, and economy. The results of field testing and data analysis show that the UAV-LiDAR hole layout technology can reduce the hole layout error from 17.4 cm to 0.1 cm, improve the operation coverage ability by 200%, and save a cumulative operation cost of 1.931 million yuan within 10 years. Meanwhile, it has an outstanding applicability in dealing with complex terrain, high temperature environments, and night work. Furthermore, this technology can provide precise coordinates for the collaborative operation of intelligent drilling machines, hole inspection robots and other equipment, promote the development of intelligent blasting, and provide a key technical support for the intelligent process of mining, with broad application prospects.

A foreign high-sulfur hematite-limonite ore contains 5.68% of sulfur and 45.95% of iron. Iron mainly occurs in hematite-limonite, and sulfur mainly exists in the form of sulfide. In order to rationally develop and utilize the ore, based on the study of the properties of the raw ore, the process flow of grinding-flotation sulfur separation-high intensity magnetic separation of iron was tested. Under the condition of grinding fineness of −0.074 mm accounting for 80%, the sulfur concentrate with sulfur grade of 41.31% and sulfur recovery of 69.74% was obtained, and the iron concentrate with iron grade of 60.84% and iron recovery of 76.92% was obtained. The sulfur content of iron concentrate meets the requirements of quality standards, and the comprehensive recovery and utilization of high-sulfur hematite-limonite ore resources are realized.

The efficient and sustainable utilization of resources can be achieved by flotation recovery of high-quality carbon components in high-ash fine-grained coal slime. Taking high-ash fine-grained coal slime as the research object, by compounding octylphenol polyoxyethylene ether (OP-10) and polyethylene oxide (PEO) for pretreatment and comparing with single reagent pretreatment flotation, it was found that the two reagents greatly improved the floatability of coal slime through synergistic effect. On this basis, the mesoscopic mechanism was analyzed by laser particle size analyzer, contact angle measuring instrument, infrared spectrometer (FTIR), Zeta potentiometer and atomic force microscope (AFM). The results are as follows. Firstly, due to the competitive adsorption relationship between the two agents, PEO agents preferentially adsorbed and exposed the alkyl chain through polar forces on the surface of the coal sample to enhance partial hydrophobicity, while compressing the hydration layer on the surface of the slime and reducing the electrostatic repulsion between the interfaces, prompting the fine coal slime to begin to flocculate into small flocs. Secondly, after the completion of PEO reagent action, OP-10 reagent began to adsorb on the surface of flocs, compressing the electric double layer of coal slime and shielding the electronegative ions. Thirdly, the two ends of the structure of the agent were adsorbed by the polar force, so that the middle aromatic hydrocarbons were partially exposed to the surface of the coal sample, showing the most obvious hydrophobic modification effect. In general, the compound reagent adsorbs in the form of single-layer adsorption and double-layer adsorption through electrostatic force and polar force to enhance the hydrophobicity of coal samples, and the adhesion force is greatly reduced after the action of the compound reagent, and the flotation efficiency is greatly improved.

A novel biodegradable surfactant of sodium N-lauroyl sarcosinate (LS) was used for copper ion flotation. The effects of mass concentration ratio of LS to Cu(Ⅱ)(ρ_LS:ρ_Cu(Ⅱ)), pH value of solution and flotation time on the flotation effect of copper ion were explored by single factor condition tests, and the flotation conditions were optimized by Box-Behnken response surface method. Finally, the verification test was carried out based on the optimization results. The results of single factor test show that at the best condition with ρ_LS:ρ_Cu(Ⅱ) of 2.5, pH value of 8, and flotation time of 5 min, the removal rate of Cu(Ⅱ) reaches 97.97%. The verification test results show that the average removal rate of Cu(Ⅱ) in the three verification tests reaches 99.71% at the condition with ρ_LS:ρ_Cu(Ⅱ) of 2.5, pH of 9, and flotation time of 4 min, which is basically consistent with the prediction results obtained by software fitting. It indicates that the model has a good fitting degree and reliability. The morphology and elemental analysis show that the structure of LS-Cu complex is loose and stable. Compared with LS, the mass concentration of Cu(Ⅱ) in the complex increases from 0.00 to 5.15%, indicating that LS has a good adsorption capacity for Cu(Ⅱ).

A systematic study was conducted on the influence of preparation conditions of caustic starch on the reverse flotation desilication effect of a certain Anshan style hematite ore in Hebei province. Through single-factor variable tests and closed-circuit process test, the optimization combination scheme of key preparation parameters such as causticity ratio, causticity temperature, and causticity time was clarified. The results show that under the optimal conditions of a causticity ratio of 8 : 100, a causticity temperature of 90 ℃, and a causticity time of 30 min, the selective inhibition performance of caustic starch was significantly improved. In the closed-circuit test, the iron grades of iron concentrate and tailings were 67.02% and 20.65%, respectively, with an iron recovery rate of 87.63%. Infrared spectroscopy and Zeta potential analysis revealed the mechanism of changes in the molecular structure and adsorption properties of caustic starch. The results confirmed that after causticization treatment, starch can effectively expose its hydroxyl and carboxyl groups, which enhances the chemical adsorption ability of the inhibitor on the surface of hematite, thereby achieving selective inhibition of hematite. The research result provides a novel approach for the green and sustainable development of the reverse flotation desilication process for hematite.

In order to solve the technical bottleneck of low reaction activity and limited usage of IOT (iron ore tailings) in preparation of geopolymers, IOT-based geopolymers were prepared with high-silica IOT and low-silica IOT as the main raw materials, metakaolin as the correction material and water glass as the alkali activator. The thermal-chemical activation was used to activate the activity of IOT. The XRD and SEM/EDS were used to analyze the changes in mineral composition of IOT before and after activation, and the influence of thermal chemical activation at 500 ℃ and 700 ℃ on the microstructure and structure of geopolymers was studied. The results show that the reactivity of IOT after thermal-chemical activation is significantly increased, the geopolymers have dense internal structure and the compressive strength is increased significantly. The suitable thermal-chemical activation temperature is 500 ℃. At the same thermal-chemical activation temperature, IOT with a 80 μm sieve residue of 10% exhibit the highest activity and the geopolymers prepared by them have the highest compressive strength. Compared with low-silica IOT, high-silica IOT can obtain a higher reactivity after thermal-chemical activation, and the geopolymers prepared with high-silica IOT have a higher compressive strength. Thermal-chemical activation causes partial transformation of low activity minerals in IOT, forming highly active minerals such as soluble sodium silicate and metastable amorphous substances.

In order to promote the high-quality development of resource-based cities, the comprehensive evaluation index, coupling coordination degree and obstacle factors of mineral-economy-mine environment in 84 resource-based cities in China from 2020 to 2022 were studied by constructing the index system of mineral-economy-mine environment and using the comprehensive evaluation model, coupling coordination degree model and obstacle degree model. The results show that the comprehensive evaluation index of mineral, economy and mine environment has increased, and the differences of resource-based cities in different types and regions are obvious. The coupling coordination degree of resource-based cities is low, most cities are in a state of imbalance, and the overall level of coupling coordination is on the rise. The main obstacle factors of the mineral system are the sales revenue of mineral products, the total output value of mine industry and the total profit of mining enterprises. The main obstacle factors of the economic system are the total import and export trade volume, the number of patent authorizations and the profits of industrial enterprises above a certain scale. The main obstacle factors of the mining environment system are the area of restoration and treatment for the current year, the cumulative restoration and treatment area, and the amount of investment in restoration and treatment for the current year.