CHINA MINE ENGINEERING

Abstract:On the basis of a brief introduction to the laws and regulations faced by international mining investment and development, this paper analyzes the composition, main sources and classification of mining rules and standards related to international mining investment, and gives a brief introduction to the main content of representative technical rules and environmental and social rules as well as the main features thereof.

Abstract:To explore the expansion trend of CO₂ phase change blasting cracking in different drillhole spacings and its application value in coal seam methane mining, CO₂ phase change blasting cracking experiments were carried out in Anshun Hongfa Coal Mine, Guizhou Province, for comparison with the result of numerical simulation of crack growth by LS-DYNA. The research shows that under the same conditions in the field test, the carbon dioxide phase change blasting has the best cracking effect with a drillhole spacing of 10m, and the permeability coefficient of the coal seam can reach about 3 times that of the original coal seam after CO₂ phase change blasting and fracturing. In the software simulation, the crack propagation of the coal seam with a drilling spacing of 10m is optimal.

Abstract:During underground mining, a safety pillar with a certain thickness is often left at certain interval to work together with the surrounding rock for supporting the overlying strata to maintain the structure of the stope and enabling a safe extraction of the ore body. The southeast ore body of Chambishi Copper Mine adopts the strip mining approach of pre-cut headspace open stoping with subsequent backfilling, where extraction is carried out in two steps with 25m-thick safety pillars left in place between the panels. To analyze the stability of the safety pillars left between the panels and provide a reference for later optimization of mining, this paper uses the FLAC^3D numerical simulation software to analyze the stress, displacement and plastic zones of the 25m, 23m, 21m, 19m, 17m and 15m thick pillars respectively after the excavation of the two-step stope is completed. The research results show that pillars with a thickness of 19m and more can meet the stability requirements. Meanwhile on-site observation shows that after the extraction of the two-step stope is completed, the 25m-thick pillars left between the panels have a perfect structure, and no phenomenon such as wall caving has ever occurred, indicating that their stability is excellent.

Abstract:By taking the Meilingnan Copper Mine in Hami City, Xinjiang as the research object, this paper has built a three-dimensional ore body model of the mining area with the help of 3DMine software; built a variogram structure model after a combination analysis and transformation of the sample data based on the principles of geostatistics; used the distance inverse power method and the block model to divide the deposit into blocks for accurate resource estimation, analyzed the estimation results, drew the trend curve of the grade of the ore body in different directions and used it to verify and evaluate the model. The results show that the model built using 3DMine software is reliable and has a high estimation accuracy, providing a reliable basis for the design of medium and deep holes in mines.

Abstract:With the advancement of deep mining of Dongguashan Copper Mine, the emergence of ground pressure has resulted in serious deformation of surrounding rocks and prominent gob caving, restricting the safe and efficient production of the mine. The mine adopts mining method of sub-level open stoping with subsequent backfilling, and the one-step room extraction adopts one-way step-by-step extraction scheme, but gob caving is serious after the one-step extraction. To verify the safety of the original mining scheme during the two-step pillar recovery, this study proposes two plans based on the one-way step-by-step mining scheme: extracting from the middle to both sides, and extracting again after backfilling following a half extraction. The finite element simulation software FLAC^3D is used to simulate the recovery process under different schemes. By using the simulated cloud map to analyze the stress and displacement of the stope, optimal stope mining sequence is chosen, which still adopts the one-way step-by-step extraction. This has certain reference significance for the exploitation of mines having the same type of engineering geological conditions.

Abstract:The severely damaged areas of the structural roadway at the bottom of the Pulang Copper Mine is mainly concentrated in the crisscross location of the faults, and the simple bolting and web-shotcreting support cannot meet the roadway stability requirements. Through a great deal of on-site damage investigation, this article has expounded the drawing crosscut failure mechanism, and based on this, proposed a wall securing, floor control and roof stabilization supporting scheme. It also conducted a comparative analysis of the existing double-layer bolting and web-shotcreting support and the wall securing, floor control and roof stabilization supporting scheme by using FLAC^3D numerical simulation software. The analysis found that the wall securing, floor control and roof stabilization supporting scheme has the effect of controlling the co-deformation of surrounding rock where fault passes through drawing crosscut.

Abstract:This paper analyzes the existing support methods and their working principles in Si ergoumen Gold Mine, uses the FLAC3D software to establish a roadway graded support mathematical model in conjunction with RQ value, the support grade index. Based on the quantitative analysis of the supporting parameters and supporting effects of various types of roadways, it developed the graded support standard for the roadway of Si ergoumen Gold Mine, which provides the basis for choosing optimal supporting scheme for various types of roadways.

Abstract:With the continuous development of science and technology, digital electronic detonators can achieve arbitrary ms settings. This paper studies the stress distribution law of delayed blasting in conjunction with shock wave theory, numerical simulation and field test methods. Theoretical calculation shows that there are more free surfaces created by delaying 3-8ms, and the blasting effect is the best. Subsequently, with the help of ANSYS finite element, a delayed blasting model in a bench hole with a height of 26m was established. Based on the energy attenuation of the shock wave acting on the rock at different air spacings at different times, the law of stress distribution after detonation was studied. The results show that by delaying the detonation in the hole by 3ms, and the energy decays slowly, which plays a good role in energy storage and buffering; The stress diffusion range in the rock mass is large, the time to reach the rock breaking strength is long, and the stress peak value decays slowly. Finally, the theoretical research results are applied to the field for confirmation.

Abstract:An underground mine uses graded tailings and waste rock for consolidated filling where there exist such problems as aging filling equipment, high bleeding rate of underground filling, and serious slurry segregation, thus, construction of a new filling system is urgently needed. In this paper, an experimental research on the materials used for total tailings filling was carried out based on available filling aggregate sources and the extraction process requirements, the slurry transport density range of 68%~72% was defined for consolidated filling with total tailings, and three types of filling slurry respectively with a concrete-tailing ratio of 1∶6, 1∶10 and 1∶20 were chosen. According to the results of the filling test, the total tailings high-density gravitating transport and filling process was selected, and a technical and economic comparison of the total tailings settling devices was carried out. Ultimately, a new type of vertical silo was selected as the tailings thickening device, which provided the basis for the construction of the filling station.

Abstract:To improve the reliability and systematization level of TSF regulation and enable a digital management and control of TSFs, this article has proposed a comprehensive application of high-resolution remote sensing, unmanned aerial vehicle and three-dimensional laser technology in TSF safety regulation, thus to obtain the “space-air-ground” multi-source data technology, and build a “health archive” for the major risk sources of TSFs based on the multi-source big data to fulfill a refined management and control of the whole process, and carry out the diagnosis-analysis-design-governance (DADT) cycle prevention and control, the process control of the whole life cycle, enabling a comprehensive measurement and control of the whole space and multi-scale of TSFs, having overcome the systematic deficiencies of the safety regulation of the TSFs existing in the past, and helped to accurately and efficiently deal with potential safety hazards, providing a scientific, efficient and complete new concept for the safety regulation of TSFs.

Abstract:The high and steep jointed broken rock slopes of open-pit mines have huge potential safety hazards, and it is of great significance to accurately monitor the rock movement and deformation of open-pit slopes. With Anqian Mining’s Yabaling Open-pit Mine as the engineering background, this article has investigated the construction of the open-pit slope monitoring system based on Beidou GNSS technology as well as its application in Anqian Mining’s Yabaling open-pit mine. The application results show that the indigenous open-pit slope monitoring system based on Beidou GNSS technology can effectively solve the problems of time-consuming, laborious and poor real-time manual monitoring, and enable an online real-time monitoring of the open-pit slopes, and it is found that the validity and accuracy of its monitoring data are high, thus, providing a reference for the monitoring and management of high and steep slopes in other open-pit mines with similar conditions.

Abstract:In order to reasonably determine the timing of abscission grouting hole completion and grouting, this paper uses FLAC^3D numerical simulation software to establish a numerical calculation model to simulate and analyze the evolution law of abscission during the advancement of the working face and the influence of the advancement of the working face on drilling. The research concluded that the timing for completing the abscission grouting drillhole is when the working face advances to 150m, and the best drilling position is 150m in front of the first cut and the middle position of the working face inclination.

Abstract:In the Carboniferous-Permian coal seam in North China, the Huanghebei coalfield in Shandong is threatened by the water hazard from the roof-floor limestone aquifer, and the mining risk of the lower coal group is extremely high. In respect of such geological conditions, and as a result of analysis, summarization and exploration, a method of double-layer multi-branch drilling grouting to transform roof-floor limestone aquifers is proposed in this article, which enables the management of roof-floor limestone aquifers. This method innovatively adopts an open section common to roof and floor drill-holes, and is used to set different management targets according to the occurrence of rock formations, in addition to specific management methods. COMSOL Multiphysics is used for numerical simulation of the control parameters of the target rock formations, and reasonable grouting parameters and drilling spacing are determined in conjunction with control experience under similar conditions in China. After the application of this method, the safe mining of the lower coal group has been realized, and it has provided a reliable technological method and scientific guidance for the development of the more than 1 billion tons of coal resources threatened by water hazard in Huanghebei coalfield, as well as other similar mines and non-coal mines threatened by roof and floor water hazard. Meanwhile, this method has great application prospects.

Abstract:With the fast and high-quality development of China’s national economy, the demand for mineral resources has grown rapidly. With thin air and low temperature all year round in plateau mining areas, the demand for heat due to downcast air preheating as well as production heating and domestic heating is high, with a high energy consumption. In this paper, Pulang Copper Mine is used as the test base. For the first time, the mine in the high altitude area adopts the ultra-low temperature air source heat pump unit for heat generation and heating, enabling energy efficient and environment-friendly heating of the mine. The upcast air from the mine contains a large amount of waste heat. The waste heat in the upcast air is recovered by the air source heat pump within the limit of one heating cycle. Compared with electric heating, the installation of waste heat recovery system for 3600 adit and 3700 upcast shaft helps save 1.48×106kW·h of electric energy per year, or 799,200 yuan of tariff per year. The installation of waste heat recovery system for 3850 adit and the south upcast shaft helps save 3.45×106kW·h of electric energy per year, or 1.863 million yuan of tariff per year.

Abstract:The beneficiation process of Mirador Copper Mine comprises bulk copper-sulfur flotation-rougher concentrate regrind-copper-sulfur separation, in which the column+cell combined process is adopted for cleaning operation. The flotation column utilizes the EFD gas-water mixture flotation columns manufactured by ERIEZ Tianjin and the column size is 5m×12m, where 3 columns are installed for Cleaning Ⅰ and 1 column for Cleaning Ⅱ. Since it was put into production in July 2019, this type of flotation column has shown a good separation effect and a strong adaptability to various ore types thanks to its high degree of automation, and is in full conformity with the cleaning operation requirements of Mirador Copper Mine.

Abstract:The mineralization geological setting of the Kunyang Phosphate’s No.2 deposit is complex, and the marine geological environment from the late Sinian to the Cambrian has created favorable conditions for the enrichment and deposition of phosphorus in the region; However, at the same time, the large-scale dolomite with multiple cycles became the direct surrounding rock or indirect aquifer of the upper and lower walls along with mineralization, and then with the compression and deformation from the crustal movement, the Xiangtiaochong anticline structure and other geological traces in the southwest part of the Kunming Front Sag, and the strata and industrial orebodies in the mine area are basically SE-dipping monoclinic structures. Analysis and practice shows that the water should be preferably drained instead of blocked when it comes to water control during the construction of inclined shafts and the use of ground penetrating radar for water detection (karst cave) along with geological drilling verification, as well as the use of geological drilling methods for water detection, water draining for pressure relief have helped ensure the safe construction of the project.

Abstract:The grade of ore extracted in mining has an important impact on the cost of downstream smelting and processing. To further improve the bauxite quality in open-pit mining, improve the efficiency of resource utilization and reduce the cost of smelting and processing, this paper conducted an in-depth analysis of the main factors affecting the bauxite ore quality in open-pit mining by taking Xingxian open-pit sedimentary bauxite mine as an example. The methods for improving the quality of ore are put forward from four aspects: technical measures, organizational measures, management measures and economic measures, providing a reference and guidance for bauxite ore quality control in open-pit mining.

Abstract:Aiming at the two most important types of pipeline projects in tailings facilities, namely the tailings transport pipeline and the tailings dam return water pipeline, this article gives an introduction to the principles that should be followed in the selection of the route schemes. In conjunction with a TSF project, and from the aspects of technology, economy, safety, environmental protection, etc., a comprehensive comparison and analysis of the three pipeline route schemes initially selected are carried out, and the analysis results show that priority should be given to tailings transportation pipeline when selecting TSF pipeline routing scheme since there are more restraints on tailings transport pipelines, and the tailings dam return water pipeline can be laid in parallel with the tailings transport pipeline; the pipeline running in the tunnels is slightly more expensive in terms of initial CAPEX, but it has more advantages in terms of environmental protection, pipeline safety and OPEX. Since the national and local government’s requirements for environmental protection and safety are getting increasingly stricter, it is a good way to properly consider the tunnel scheme in the selection of the TSF pipeline routing scheme, by taking into account factors such as economic conditions.

Abstract:Copper-lead-zinc polymetallic sulfide ore is an important non-ferrous mineral resource. The type of mineral resource has various properties and the mineral process flowsheets are complex and diversified. This paper summarizes the currently common copper-lead-zinc polymetallic ore mineral process flowsheets and flotation reagents used in China, and analyzes their future development direction.