CHINA MINE ENGINEERING

Abstract:Pillar stability is the premise of safe and efficient mining in mines. It is of great significance to study the factors affecting the stability of pillars and their sensitivity for the safety management of pillars. In this paper, a method for analyzing the influencing factors of pillar stability based on rough set theory is proposed, and a manganese ore room-and-pillar mining stope in Sichuan Province is taken as the research object. Firstly, the influencing factors of pillar stability were analyzed. Then, the sensitivity analysis of each influencing factor is carried out by using rough set theory, and the importance of each influencing factor to pillar stability is calculated. The results show that the importance of room width is 0.381, which has the most significant effect on the stability of pillar. The method is objective and effective for the sensitivity analysis of the influencing factors of pillar stability, which can provide theoretical basis for the safety management of mine pillar and the optimization of pillar size.

Abstract:There is a landslide at an elevation of 150m on the north slope of the Yangjialing mining area, which has caused significant damage and deformation to safety production. The landslide rock belongs to the Gufeng Formation shale. In order to explore the macroscopic and microscopic failure mechanisms of the rock, using X-ray powder diffraction, scanning electron microscopy, MTS816 electro-hydraulic servo control testing machine to study it. The experimental results show that the shale in the study area is mainly composed of detrital mineral quartz and clay mineral illite, a small amount of chlorite and kaolinite, and the rocks have a certain degree of water absorption; The whole interior of siliceous shale is flaky structure, containing pores with a diameter of approximately 0.61~4.01μm,and primary cracks with a length of approximately 1.09~2.95μm. Under uniaxial compression, the compressive strength and elastic modulus of rocks increase exponentially with the increase of loading rate. At low loading rates, shale has a significant yield stage and the failure mode is brittle tensile failure; Under triaxial compression, the average compressive strength of shale decreased by 15.31% to 20.40%, and the cohesion decreased by about 16.57%. Confining pressure can improve the compressive strength of saturated shale, which mainly occurs brittle shear failure with a failure angle of about 67.38°; The damage strength and peak strain of rocks are most significantly affected by confining pressure, and the sensitivity of their strength to confining pressure is in the order of damage strength＞peak strength＞initiation strength. The research results indicate that the mineral composition and microstructure of shale in the study area may be the main reasons inducing its macroscopic failure.

Abstract:This article takes a tailings pond in Miyi County, Panzhihua City, Sichuan Province as the research object. FLO-2D numerical simulation software is used to simulate tailings ponds with different forms of dam failure, and the results are compared and analyzed to determine the impact range of dam failure and ensure the personal and property safety of downstream residents. By calculating the flood overtopping parameters of tailings pond, the dam failure parameters of single point instantaneous dam failure and multi point instantaneous dam failure, and substituting them into FLO-2D software, the corresponding numerical simulation results are finally obtained. The results show that under all forms of dam failure, single point dam failure causes the most accumulation and destruction, with most of the tail fine sand and tail powder sand concentrated in the rear section of the main dam. In contrast, multi point instantaneous dam failure has weaker damage to the affected area, and the degree of disaster is relatively mild. However, the affected surface area significantly increases, and the tail sand deposition is the widest, mainly distributed in the initial dam and flooded areas of each dam body; However, due to the minimum flow rate of dam failure caused by flood overtopping, compared to instantaneous dam failure, the damage is relatively small and the affected area is the smallest. Tailings are mainly deposited in the river channel, but it should be noted that when accompanied by a large amount of rainfall, this disaster may also cause other secondary disasters.

Abstract:This article is based on the diffusion theory of relative volume concentration H M. The Ismail equation is combined with the flow state discrimination criteria of E.J. Vasp and Wang Shaozhou slurries, and Liu Dezhong’s exponential calculation method is used to determine the flow state discrimination calculation of slurries. The volume concentration of quasi homogeneous slurries and heterogeneous slurries are obtained, and based on the relative volume concentration of slurries, the concept of coarse and fine particle boundary particle size is proposed. On this basis, the concept of heterogeneous slurry volume concentration increasing resistance is proposed, and the concepts of boundary particle size and increasing resistance are defined, Derive the formula for calculating the resistance of slurry pipelines using the drag coefficient method, which has been verified by six long-distance slurry pipeline projects in China. The calculation results are similar to the actual engineering situation.

Abstract:In recent years, digital twin technology has developed rapidly and has made great progress in smart cities, smart parks and other fields. However, due to the uncertainty of mineral resources, the mobility of the operation site and the diversity of production processes, the development of digital twin in mining industry is slow and there are few successful cases. The author's team has independently developed the MIM digital twin platform based on years of practical engineering experience in the industry, combined with multiple disciplines such as intelligent equipment, industrial automation, 5G, and data governance platforms. It has been widely applied in the Yanqianshan iron mine. By applying the MIM digital twin platform, Yanqianshan Iron Mine has achieved unmanned or intelligent operation of some processes, improved enterprise management efficiency, optimized production design accuracy, reduced the number of operators, and achieved good results. This article first provides an overview of the MIM digital twin platform and related MIM digital twin systems, then summarizes the main highlights of the Yanqianshan project, and finally summarizes the innovative application of digital twin technology in this mine and proposes future directions for development.

Abstract:In recent years, with the needs of mine large-scale,upsizing,environmental protection and other needs, SAG mill has gradually become the mainstream grinding equipment of processing plant, but because of the grinding characteristics of SAG mill , the sensitivity of head ore properties is higher than that of conventional grinding and high pressure roller grinding and other systems, so how SAG mill to reach the production target, keep the production capacity and increase the production capacity is an important part of mine enterprise exploration and practice. This paper analyzes and improves the reasons for the failure of 7.5m×3.2m SAG mill in a processing plant, puts forward a variety of methods to improve the production capacity of SAG mill, and carries on the corresponding evaluation for reference when similar mines enterprise facing this problem.

Abstract:In order to solve a series of problems such as serious roof leakage and rib spalling, poor support effect, low tunneling efficiency and restricted mining progress in the roadway under the coal roof of extremely soft and fragile thick coal seam, the outer section of 842 air roadway in Wobei Coal Mine is taken as the research object. Based on the investigation of its engineering geological conditions and the deformation of roadway under the original support mode, the full-length anchorage technology of prestressed anchor cable in loose coal body is put forward, which is expected to further improve the tunneling level of fully mechanized caving face in extremely soft and fragile thick coal seam in China.

Abstract:Ensuring the stability of the bottom plate is the foundation for achieving safe coal mining in the fully mechanized top coal caving face. However, when there is a goaf underneath the mining area, the mining face often faces problems such as roof collapse and instability of the fully mechanized top coal caving equipment, which greatly restricts the safe coal mining and is a key problem that mines need to solve. Taking the 6303 fully mechanized mining face as the engineering background, the drilling method was used to determine the position of the overlying 9 # coal seam goaf, and the stability of the bottom plate during the mining face recovery period was analyzed through theoretical and numerical simulation technology. A reinforcement technology scheme for the goaf was proposed and applied in engineering. The research found that: ① the plastic zone of the bottom plate after the mining face recovery is connected to the overlying goaf roof, and the stability of the bottom plate is poor, After reinforcing the goaf, the stability of the working face bottom plate can be significantly improved; ② Based on the analysis of existing reinforcement materials, it was found that the filling material for the goaf can not only meet the reinforcement needs of the goaf, but also reduce the reinforcement cost and construction volume of the reinforcement project Provide a specific reinforcement drilling layout plan, filling process, and safety technical measures based on the layout of the mining roadway and detection roadway in the 6303 fully mechanized mining face. After engineering application, when the 6303 fully mechanized mining face passed through the goaf of the overlying 9 # coal seam, the working face floor and fully mechanized mining equipment remained stable, and there were no abnormalities in the mining equipment, roof and floor, and mine pressure, indicating that the reinforcement technology used had a significant effect.

Abstract:The mechanical arm of mining equipment is a component with flexible structure. During mining work, the mechanical arm is subjected to heavy load and strong impact, which affects the mining efficiency and working stability of the equipment and leads to equipment failure. Mining equipment work environment is complicated, vibration signal acquisition and fault analysis work is more difficult. Taking the rocker arm of shearer as an example, in order to test the vibration signal of the mechanical arm of mining equipment, a test platform simulating the vibration signal of the rocker arm of shearer is designed. The vibration signals of the rocker arm under various working conditions are collected experimentally, and the network model for analyzing the transverse vibration data of the rocker arm is established. The lateral vibration model of rocker arm is fitted by neural network, which greatly reduces the error of manual analysis and provides data basis for mining equipment working condition monitoring and fault prediction.

Abstract:Based on an industrial experiment at a domestic tungsten mine, a systematic analysis was conducted on the ore feed size, reject rate, and equipment processing capacity in the photoelectric sorting process. With an original ore grade of 0.22% and an ore feed size of 10~40mm, the use of the K-108 photoelectric sorting equipment yielded a tungsten concentrate with a grade of 0.26%, a reject tailings tungsten grade of 0.046%, a reject rate of 21.84%, and a tungsten metal recovery rate of 95.38%. The photoelectric sorting process showed a significant separation effect for this tungsten mine. The study identified that non-standard ore sampling was the fundamental reason for the high reject and concentrate recovery rates in the industrial test, and the sorting cycle load was a key factor affecting the stability of the sorting process.

Abstract:The Baifang Copper Mine is located in the southern edge of the Hengyang Basin, where multiple structures are superimposed and composite. Folds, faults, unconformities, karst, and other factors in the area play an important controlling role in the formation and spatial distribution of the ore body. Deep exploration is difficult. Physical property tests have shown that there are significant differences in the electrical properties of rocks (minerals) from different strata in the area. The use of wide area electromagnetic methods can effectively analyze and predict geological characteristics such as rock development, structural morphology, fault distribution, and spatial distribution of rock masses. By implementing 7 wide area electromagnetic sounding profiles, conducting systematic processing and quantitative inversion calculations, the geological boundaries of the deep strata, structures, rock masses, and other geological bodies of the Baifang Copper Mine are inferred. Combined with the spatial positioning mechanism and laws of the ore body, the ore-forming geological body geophysical prospecting indicators are established to predict favorable ore-forming target areas. After verification by drilling engineering in the later stage, the results of the wide area electromagnetic method are in good agreement with the geological and structural development revealed by the engineering, providing sufficient geophysical basis for conducting edge and deep exploration.

Abstract:Process design, equipment selection, investment estimate and technical and economic comparison between HPGR final grinding and traditional crushing-ball mill process were conducted for a copper mine in Pakistan. The results indicate that HPGR final grinding process is longer, with more equipments and installation power comparing to traditional crushing-ball mill process. The investment of HPGR final grinding process is 10874 thousand dollar higher than that of traditional crushing-ball mill process. Energy consumption of HPGR final grinding process is higher than that of traditional crushing-ball mill process, but the operating cost of HPGR final grinding process lower, because no steel ball and ball mill liner consumed. Annual operating revenue and net profit of HPGR final grinding process are 4398.7 and 4601.2 thousand dollar higher than that of traditional crushing-ball mill process. In the long run, HPGR final grinding process can generate more better economic benefits for this copper mine, which has better industrial application value.

Abstract:The digital transformation of the traditional metal mine industry is accelerating. Different data format standards, sharing difficulties, data islands and other problems still exist. This paper, specifically discusses the necessity and the key problem of digital delivery. At the same time, it also gives the specific methods of digital delivery, analyzes the functions of the digital delivery platform, which can provide a reference for the digital delivery of the metal mine industry.

Abstract:Copper mainly exists in the form of primary copper sulfide in a copper mine in Hubei, and the main gangue minerals are garnet and quartz. It was difficult to obtain a high recovery rate of copper-bearing minerals because of the uneven medium-fine dissemination, complex inlaying relationship, and low liberation degree. The grind fineness of the primary grinding and regrinding were determined to be 70.59% under 0.074mm and 92.93% under 0.045mm, respectively. The mixed collector of isobutyl xanthate/ammonium butyl aerofloat (2∶1) was adopted in a flow of bulk flotation-Cu-S separation-centralized return of middling. A concentrate with a copper grade of 20.33% and recovery of 91.21% was gained from a 0.62% copper-bearing ore. The results provide guidance for process optimization and improving copper recovery rate.