CHINA MINE ENGINEERING

Abstract:In order to explore the safety impact relationship between surface structures and underground mining projects, and solve the contradictory community of underground mining and surface safety, this paper uses GIS geographic information software and Rhino+griddle modeling software to conduct three-dimensional modeling of the current terrain, construction (structure) distribution, underground ore body and reconstruction and expansion project of a gold mine. In addition, FLAC3D finite difference software was used to simulate the excavation of underground ore body. The simulation scheme was divided into non-filling mining scheme (the most unfavorable case) and upward horizontal slicing and filling mining scheme (the most conservative case). Considering the limitations of filling technology, the upward horizontal slicing and filling mining scheme was divided into empty top 1m and empty top 0.5m simulation. The surface displacement and deformation values generated by the two mining schemes meet the requirements of the Regulations on Coal pillar maintenance and coal pressing in Buildings, water bodies, Railways and Main shafts and lanes. The upward horizontal filling mining greatly reduces the displacement and deformation value of the surface, which is more conducive to the stability and safety of structures.

Abstract:In order to scientifically mine the near-surface broken orebody and ensure the safety of surface structures, the combination of rock drilling and filling method and upward approach filling method is proposed. FLAC3D software was used to simulate the whole process of excavation and filling under different quarry structural parameters of the two scenarios, and to analyze the stability of the quarry perimeter rock and the ground surface. The results show that: when mining with the two structural parameters of 6m (width)×10m (height) for segmented rock drilling and segmented mine subsequent filling method and 4m (width)×4m (height) for upward approach filling method, the phenomena of top and bottom sinking and bottom bulging are not obvious, the range of stress concentration of the ore column is the smallest, and there is no large area of plastic zone penetration in the mine peripheral rock, so the overall solidity is the best; After the end of mining, the maximum settlement displacement of the surface is 4.27mm, the maximum value of inclination is 0.101mm/m, the maximum value of curvature is 0.842mm/m2, and the maximum value of horizontal deformation is 0.056mm/m. The results of the analysis of various indexes show that the mining of the ore body in accordance with the design scheme has very little impact on the surface buildings and structures. The study may provide experience in mining back similar ore bodies.

Abstract:In this paper, a series of optimization strategies are proposed to solve the problems of crushing zone treatment technology in underground mine backfill mining. Firstly, the process of backfill mining and the stability problems of the crushing zone frequently encountered in the implementation process were sorted out, and the shortcomings of the current solutions were analyzed. Secondly, based on theoretical analysis, the relevant mathematical model was constructed and the parameters were optimized to evaluate the effect of different treatment schemes. On this basis, combined with specific mine examples, the process and effect of optimization technology in practical application are discussed in detail. Finally, through the study of different filling materials and the discussion of measures to improve the stability of the crushing zone, this paper makes a comprehensive analysis of the technical optimization measures, including cost-effectiveness considerations, to ensure the feasibility and economy of the proposed optimization strategy. This study is of great significance for improving the efficiency and safety of underground mine backfill mining.

Abstract:Taking the ecological restoration project of consolidated backfilling in the open-pit of Fengshan Copper Mine as a case study, this paper focuses on discussing the key technologies for ecological restoration through consolidated backfilling in open-pits, Additionally, numerical simulation software is used to conduct an in-depth analysis of the correlation between the ecological restoration project of open-pit consolidated backfilling and the underground mining project in terms of safety and other aspects. The study shows that scientifically and rationally carrying out ecological restoration projects through open-pit consolidated backfilling can create favorable conditions for green and waste-free mining in mines, achieve a win-win situation between ecological benefits and economic benefits, and provide important references for the sustainable development of similar mines.

Abstract:针对邻近采空区硐室影响区巷道围岩变形严重问题，以5206回风巷过邻近5204采空区绞车硐室为研究对象，分析围岩变形严重原因并针对性给出围岩控制技术方案。具体通过采用注浆方式提升煤柱稳定性并封堵漏风裂隙，利用充填柔模袋维护硐室及煤柱稳定性，在煤柱帮浇筑混凝土墙体提高煤柱稳定性，利用架棚提高支护强度。现场应用后，5206回风巷得以安全顺利掘进过5204采空区绞车硐室影响区，期间顶底板及巷帮围岩保持稳定，巷道变形量较小且未发现邻近采空区瓦斯外泄问题。

Abstract:Based on the study of block caving method in inclined ore bodies in some mines at home and abroad, this article uses PCBC software and combines factors such as ore body collapsibility, ore body morphology, induced stress, rock mass structure characteristics, and mining safety to study the undercutting sequence of block caving method in Panjiatian Iron Mine. The research results indicate that PCBC software has practical value in determining the optimal mining height, calculating the mineable amount, determining the undercutting sequence, and preparing production schedule plans, providing reference value for determining the undercutting sequence of block caving method in similar mines.

Abstract:This paper addresses the bifurcation instability of deep roadway surrounding rock under the coupled effect of anisotropic tectonic stress and geometric non-coaxiality. Based on the higher-order Cosserat continuum theory, a nonlinear constitutive model with micro-structural rotational degrees of freedom is developed, and the bifurcation instability criterion considering the couple stress tensor is derived. Using analytical and numerical methods, the critical instability threshold of the roadway axis (N45°E) and maximum principal stress (N43°W) at an oblique intersection in the Dengjia Fireland section of Qingping Phosphate Mine is revealed. The study shows that when the anisotropic coefficient of tectonic stress χ＞0.35, the plastic zone of the surrounding rock expands in a bifurcation mode, with a critical stress threshold of 0.72σ_c. This work provides theoretical support for deep roadway stability control.

Abstract:Rock burst is a sudden dynamic disaster in the process of underground construction, which poses a serious threat to the safety of personnel and equipment. Based on the construction area of a drainage roadway in a copper mine in Xizang Province, this paper applied indoor uniaxial compressive strength test, Brazilian disc splitting strength test, loading and unloading test to obtain the rock physical and mechanical characteristics of the construction area. The composite rock burst prediction of rock at different locations and buried depths is carried out by using four rock burst criteria, namely linear elastic index criterion, strength brittleness index criterion and deformation brittleness coefficient criterion. The conclusion shows that the rock burst tendency in the construction area is weak rock burst tendency and no rock burst tendency, and the rock burst occurrence probability is small and the degree is slight. Rock burst disaster can be prevented and controlled by adopting general support measures in the construction process of drainage lane. The rock burst prediction analysis based on multiple rock burst tendency criteria provides a theoretical basis for rock burst disaster prevention in the construction area of drainage lane.

Abstract:A certain iron ore dumping site is located in the tail area of a newly built tailings pond. After the operation of the tailings pond, the tailings will gradually submerge some areas of the dumping site. The maximum submergence height of the first phase tailings pond is 21 meters. After the operation of the tailings pond, the maximum height of the iron ore dump will be submerged by 66m in the final stage. After the tailings pond submerges the waste dump, it will have a significant impact on the stability of the waste dump. Once the waste dump slides, it will also affect the safety of the tailings pond. Therefore, it is particularly important to study the mutual influence and stability between tailings ponds and waste disposal sites. This article adopts a three-dimensional finite element simulation research method to study the stability of a certain iron ore waste dump under the condition of tailings pond inundation. Based on the research results, an engineering treatment plan is proposed to provide reference for future project construction under similar conditions.

Abstract:This article studied the tailings sedimentation beach morphology and particle sorting characteristics under the influence of two factors, namely discharge slurry concentration and flow rate, through dam stacking experiment. The recommended optimal slurry concentration is 30% to 34%, and the flow rate per unit width is 3.3L/m. Through practical operation, it has been verified that within the recommended range, the tailings sedimentation has a relatively long dry beach, a flat beach surface and a moderate slope, which is basically consistent with the results of the dam stacking experiment.

Abstract:In order to ensure the safe and reliable operation of the tailings drainage system, a hydraulic model test was carried out on the drainage system of a second-class tailings reservoir. The hydraulic characteristics of the drainage well and tunnel were tested through different schemes and different working conditions, and the discharge rate, flow pattern, pulsating pressure and aeration concentration were studied. The test results can provide references for the engineering design of the tailings drainage system.

Abstract:Taking a certain gold mine as the research object, this paper focuses on the impact of different flotation processes on the effective recovery of gold. The focus of this study is on the effects of rapid flotation processes and conventional flotation processes on the effective recovery of gold. By using the rapid flotation process, a gold grade of 74.01g/t with a recovery rate of 87.12% can be obtained from the rapid flotation gold concentrate 1, and a gold grade of 81.42g/t with a recovery rate of 9.63% can be obtained from the flotation gold concentrate 2. The total gold grade of the concentrate is 74.69g/t with a gold recovery rate of 96.75%. By using the conventional flotation process, a gold concentrate with a gold grade of 80.06g/t and a recovery rate of 95.83% can be obtained. This study provides different ideas for effective gold recovery, improves the gold recovery rate, and provides important technical support for the effective development and recovery of similar gold mines.

Abstract:A lithium mica mine in Jiangxi Province, where the ore is characterized by high clay content. During the mineral processing, the primary/secondary sliming of ore affects the flotation conditions of lithium mica, leading to a deterioration of flotation conditions, resulting in a loss of lithium mica recovery rate and poor concentrate grade. To address the issue of low recovery rate of high-clay lithium mica, a mineral processing experimental study was conducted using the “cyclone desliming-flotation” process. The experimental results show that under the conditions of a slurry concentration of 30%, the sodium hexametaphosphate dosage of 350g·t^-1, and the collector EF1128 dosage of 400g·t^-1 under the roughing processing, the the lithium mica concentrate concentrate was obtained with Li₂O grade and operating recovery of 1.65% and 86.13%, respectively, by using of one roughing, two cleaning, two scavenging, and middles back to the flowsheet in turn.

Abstract:Taking high sulfur copper zinc ore as the research object, based on the study of process mineralogy, according to the characteristics of the ore, the influence of grinding fineness, adjusting agent type, and collecting agent type on copper zinc sulfur recovery is studied, and suitable mineral processing technology and reagent system are developed. The experimental results show that using the process of two coarse, one scavenging, five fine, and three fine sweeps of copper and zinc can obtain a copper zinc mixed concentrate with a copper grade of 6.90%, a copper recovery rate of 85.54%, a zinc grade of 39.48%, and a zinc recovery rate of 94.76%; By adopting a process of one coarse, one scavenging, and three fine, a sulfur concentrate with a sulfur grade of 49.09% and a sulfur recovery rate of 72.48% can be obtained, with a sulfur operation recovery rate of 85.03%. This study can achieve efficient recovery of copper, zinc, and sulfur from high sulfur copper zinc ores, providing important guidance for the comprehensive development and utilization of this type of mining resource.

Abstract:To study the chemical characteristics and genesis of groundwater in the Feitianyan mining area of Chaozhou, 15 sets of groundwater samples were collected and subjected to conventional ion testing (including pH value, K+, Na+, Ca2+, Mg2+, Cl-, SO2-4, HCO-3, TDS, etc.). Through the use of SPSS software and Origin software, multidimensional methods such as mathematical statistical analysis, Piper trilinear plot drawing, Gibbs plot model analysis, ion ratio analysis, correlation analysis, and factor analysis were conducted to reveal the hydrochemical composition types of groundwater and the controlling factors of their evolution process. The results show that：（1）The pH value of groundwater in the study area is weakly acidic. The cations in the water body are mainly Na+, and the anions are mainly HCO-3. The groundwater is mainly HCO3·Cl-Na·Ca type water, followed by Cl-Na type water, a small amount of Cl·SO4-Na, HCO3-Na type water.（2）The main ion composition is influenced by the interaction between water and rock, with ions originating from the weathering of silicate minerals and the dissolution of evaporite minerals, as well as the alternating adsorption of cations; In addition, atmospheric precipitation under the influence of human activities is also a major contributing factor to the chemical composition of water.