CHINA MINE ENGINEERING

Abstract:Aiming at the problems of deep rock mass quality evaluation and support system optimization in Jinxing Gold Mine, based on the geological mechanics RMR classification system, taking the roadway in the middle section of Jinxing Gold Mine -450m as the research object, and applied in the roadway in the middle section of Jinxing Gold Mine, the RMR score of the rock mass is 45, the rock mass quality is Ⅲ and the lithology is good. Based on the results of rock mass quality classification, the paper puts forward the combination of theoretical calculation and numerical simulation, and the multilevel support application test of industrial classification zones in selected areas to select the best supporting materials and parameters, so as to ensure the economic benefits of mines.

Abstract:Rock mass occurrence characteristics is of great significance for block caving mining method. This paper based on the study of rock mass occurrence characteristics and physical-mechanical properties of Tongkuangyu Mine in deep, discussing about rock mass cavability, provides vital guidance for mining with block caving in deep. The results show that there are two dominant joint groups in the rock mass of No.4 and No.5 orebodies with NW and SE trending tendencies, and the joint planes dip sharply. The engineering classification of rock mass is hard to harder; rock mass quality classification is II to III and rock mass cavability is moderately to hard, which would result in caving mining with medium broken and more bulk. The method of rock mass pre-conditioning by hydraulic fracturing should be adopted actively in the deep mining, with reasonable planning undercutting place and direction and rate of the first mining area, and supplemented by appropriate inducement projects such as pre-splitting and boudary solt, to improve the rock mass cavability in the deep mine, for the successful use of block caving mining method.

Abstract:This study aims to significantly reduce the complexity of Mixed Integer Linear Programming (MILP) mathematical models in mining applications by using a hierarchical clustering algorithm for pre-processing block data, thereby solving complex problems in mining scheduling optimization. The essence of this method lies in the aggregation of numerous small blocks into relatively fewer and larger consolidated units based on the similarity of geological and mining-related properties of the blocks. This approach simplifies the variables and constraints of the model, reducing the computational resources and time required to solve optimization problems. An application case study of a large open-pit gold mining complex demonstrates the effectiveness of the hierarchical clustering algorithm in practice. The original MILP model, due to the immense number of blocks and high computational complexity, was not directly solvable. After applying the clustering algorithm, the number of blocks was sensibly reduced from 36183 to 5810 consolidated units, significantly reducing the scale of the problem.

Abstract:With underground mining continues to operate at large buried depths, the operating environment such as ventilation, safety, and drainage is becoming more and more complex. The selection of different mining methods is particularly important for the sustainable development of mines. Based on the mining technical conditions of Pakrut Gold Mine, this paper selects four mining methods (caving method, upward layered filling mining method, segmented empty field subsequent filling method, and terraced empty field dry filling method) and 8 evaluation indicators (production capacity, cutting ratio, loss rate, dilution rate, operating cost, ventilation conditions, production organization, safety conditions). And then the AHP-Fuzzy-TOPSIS analysis model is used to calculate the accessible degree of three representative middle sections of 2292m, 2050m and 1930m, and the results are analyzed, which fits with the actual production situation of the mine and verifies the validity of the method. feasibility. It provides a theoretical basis for the selection of the mining method in the middle section of 1930m in the next step, and also provides a certain reference for other mines to choose the optimal mining method in different production stages.

Abstract:At present, the domestic mine design is still based on the conventional two-dimensional design and drawing delivery, the shaft design for the shaft ingate, the chamber and the intersection of the shaft is difficult, the design workload is complicated, the design time is long, the error is easy and the verification is relatively difficult.Based on the background of a shaft project in a lead-zinc mine in Turkey, this paper introduces the calculation books related to shaft 3D design, the 3D modeling of shaft excavation and shaft equipment, and the digital delivery cases of software output construction drawings. Through the vertical shaft 3D design, the shaft construction drawing design task can be completed quickly and accurately, greatly reducing the workload of designers and improving the design efficiency. Compared with the current two-dimensional cad model, it can save 1~2 months.

Abstract:A iron mine ecological restoration project is to backfill the open-pit using tailings cemented solidification method. It is planned to build afilling station around the open-pit. In order to demonstrate the safety and reliability of slope and filling station, the limit equilibrium analysis method and the numerical simulation method were used to calculate and analyze the slope stability under the load of the filling station. The calculated results show that the slope under the load of the filling station is basically stable when the open-pit is backfilled to -354m, and the slope is under stable state when the open-pit is backfilled to -300m. In order to ensure the safety of the slope and the filling station, it is recommended to strengthen the monitoring of the slope where the filling station is located. And the construction should be carried out under the premise that the slope in the region is stable.

Abstract:SHPB dynamic test bed was used to carry out impact tests on red sandstone samples with different fracture dips, recording the mass-particle size distribution after rock fragmentation and calculating its fractal dimension, to analyze the fractal characteristics of rock crushing and the law of energy consumption under impact load. The results show that: Under the same impact load, the dynamic compressive strength increases and the strain rate decreases with the increase of the crack dip angle, and the dynamic compressive strength increases most obviously when the dip Angle increases from 45° to 60°; The existence of prefabricated cracks in rock samples will hinder the transfer of stress waves, leading to the increase of reflection energy and the decrease of transmission energy. Moreover, with the increase of inclination Angle, the influence of prefabricated cracks will be gradually weakened, while the reflection energy and transmission energy will be continuously reduced and the dissipated energy will be almost not affected by the inclination Angle of cracks; The fractal dimension of fractured rock mass increases linearly with the increase of fracture dip angle and dynamic compressive strength and decreases with the increase of strain rate. The relationship between fractal dimension and rock-crushing dissipation energy satisfies the power function.

Abstract:It is difficult to objectively and accurately evaluate the safety status of gas prevention and control systems in gas outburst mines. This article first analyzes the factors affecting the safety status of the mine gas prevention and control system, and based on this, constructs a safety status evaluation system for the mine gas prevention and control system. Secondly, based on the Analytic Hierarchy Process and combined with the Particle Swarm Optimization (PSO) algorithm, the judgment matrix is optimized and modified, and the weights of each indicator in the evaluation system are calculated on the basis of reducing subjective influence. Finally, based on cloud theory and the weights of secondary and primary indicators, the cloud digital features of the total indicator are calculated, and a standard cloud model for evaluation indicators is generated using a forward cloud generator in Matlab. And taking a typical gas outburst mine in Guizhou Province as the research object, combined with the actual investigation situation of the mine site, the comprehensive discrimination and evaluation standard index cloud of the safety status of the mine gas prevention and control system was obtained, and the accurate evaluation of the safety status of the mine gas prevention and control system was made, and corresponding rectification measures were proposed. The research results have important significance for the objective and accurate evaluation of the safety status of gas prevention and control systems in gas outburst mines and for coal mine safety production.

Abstract:In order to explore the fragment provenance and structural environment characteristics of Carboniferous-Permian sedimentary rocks in Shixi area, eastern margin of Ordos Basin, some tests were carried out on the analysis of major and trace elements, mineral composition and casting thin-section of 26 mudstone samples and 17 sandstone samples. The results show that the sandstone clastic particles in the study area is mainly composed of quartz, feldspar, mica and debris. The average content of debris is higher than 20%, igneous rock debris mainly consists of volcanic tuff debris and intrusive rocks debris, accounting for 78.9%~87.2% of total content of debris, which means pyroclastic rock-volcanic lava system is the main provenance area; The parent rock of the Carboniferous-Permian terrigenous clastic in study area is felsic igneous rock, and the provenance area is recycling orogenic in southern margin of the Ordos Basin, where the terrigenous debris suppy is related to the Permian tectonic evolution of North Qilian orogenic belt.

Abstract:After the mining of the 53-01 working face, it is easy to form a large area of suspended roof. When the suspended roof bends, suddenly fractures, and collapses, it can cause impact disasters. By establishing a mechanical model of the cantilever structure of the top plate, the main factors affecting the impact of ground pressure on the span l of the cantilever structure are obtained. Propose to reduce the risk of impact in the working face by combining the weakening of the suspended roof structure, the restoration of the tunnel section, and the anti impact of the composite weak structure. After pressure relief, the average amount of drilling cuttings is 2.86kg/m, which is stable at around 2.9kg/m and within a safe range, achieving good results in anti erosion.

Abstract:In order to analyze and evaluate the slip stability of dangerous rock body formed by the combination and cutting of steep-inclined structural planes, taking the dangerous rock body of Longsi CIV-1 slope as an example, a simplified geological model, a generalized theoretical model of instability and a mechanical analysis model of dangerous rock body under the influence of frost heave, earthquake and hydraulic factors were established according to the measured data, the dimensionless calculation formula of coefficient of sliding stability of dangerous rock body is derived by using limit equilibrium theory and assumption of improved groundwater pressure distribution. using mathematical model focuses on the influence of various factors on the slip stability of the dangerous rock body, and diagrams get drawn which express the relationship between freezing effect, seismic effect, hydraulic effect, the geometry of the dangerous rock body and the coefficients of slip stability when the dangerous rock body is saturated. The calculation example analysis shows that: the slip stability of the dangerous rock body gradually decreases as frost heave coefficient increases; it decreases as bedding plane or height of posterior edge crack increases, and the larger bedding plane or height of posterior edge crack, the more sensitive the effect of frost heaving on stability will be; it decreases as vertical or horizontal seismic action coefficient increases, and the effect of horizontal coefficient is more significant than vertical coefficient, However, the sensitivity of the effect of horizontal coefficient and vertical coefficient on the stability of the dangerous rock body is different under various hydraulic states; In addition, it decreases as height and angle of vertical face in front of slope increases , and the rate of its decrease declines with the increase of height or angle of vertical face in front of slope.

Abstract:Metal mine intelligence is the core guarantee for the high-quality development of mining, the establishment of a underground metal intelligent mine system architecture, the construction of a standard system, strengthening infrastructure, accelerating the evolution of intelligent ecology, deepening the application of industrial integration, and improving security are the basis and guide for the intelligent underground mining of metal mines. In view of the current problems such as the lack of a systematic architecture and model for the intelligent construction of underground metal mines, the lack of top-level overall planning and design, and the easy occurrence of repetitive construction, this paper proposes a mature system architecture and technical path, and has achieved good results in practical application, which has enhanced the overall supporting role of the intelligent standard of underground metal mines and promoted the development of the metal mineral industry.

Abstract:The intermediate ore storage facilities mainly include coarse ore piles and coarse ore silos. In the design process, there is always no unified regulation for the selection of coarse ore piles and coarse ore silos. This paper is based on the upgrading and renovation project of a certain molybdenum mine. Through a detailed comparative analysis of the coarse ore heap and the coarse ore bin, the final plan is to choose a conical coarse ore heap with a diameter of 85m as the optimal one. Through the analysis of the overall layout of the factory area, it is determined that the coarse ore heap is located on the west bank of the Wenyu River, south of the Qinling Ecological Red Line, and meets the requirements of ore heap construction through river diversion. Diversion of the river to meet the requirements of mining pile construction.

Abstract:Taking a certain laterite nickel ore as the research object, this study explores the feasibility of using mineral processing technology to remove the chromite, in response to the problem of its containing chromite being unfavorable for subsequent wet smelting. The experimental results show that the use of a hydraulic cyclone classification-shaking table gravity- magnetic separation process can effectively remove chromite from laterite nickel ore, with a chromite removal rate of 50.99%. The chromium grade of chromite ore is 34.32%, and the chromium iron ratio is 2.03, which meets the smelting requirements and achieves comprehensive resource utilization. Meanwhile, the distribution rates of nickel and cobalt in wet metallurgical products are 99.51% and 97.17%, respectively, indicating a relatively low loss rate of nickel and cobalt. This study can effectively remove chromite from laterite nickel ore, providing important guidance for the comprehensive development and utilization of this type of laterite nickel ore.