CHINA MINE ENGINEERING

Abstract:The extraction of mineralized alteration information and the interpretation of remote sensing geological structure play an important role in ore deposit location. Taking Xialonggang lead polymetallic mine as an example, Landsat8 OLI data was selected to extract alteration information by means of principal component analysis, band ratio method and secondary principal component analysis, including interference signal removal, anomaly information extraction, anomaly classification and median filtering. The mixed anomaly information of iron stain and hydroxyl group was extracted by the secondary principal component analysis method. Five prospecting potential areas were identified through the analysis of remote sensing alteration information combined with remote sensing geological structure interpretation. The mixed alteration and variation of iron stain, hydroxyl group, iron stain and hydroxyl group were often superposition in the metallogenic prospect area, indicating that the Xialonggang area has good metallogenic potential. It provides scientific basis for geological prospecting in Xialonggang.

Abstract:The step slope formed in the upper part of an open pit is filled with loose loose body, which has some hidden danger. In order to control the influence of subsequent blasting operation on slope stability, vibration test was carried out in the slope during blasting operation. ANSYS numerical simulation software is used to simulate the dynamic response law of the slope under blasting vibration, study the change characteristics of effective stress and plastic strain, and prove the reliability of the simulation by comparing the acceleration and velocity of the slope bottom, and then determine and analyze the safety and stability of the slope under the dynamic vibration load of blasting operation. The influence of seismic wave on the stability of loose accumulation slope under blasting operation is studied. The results show that the slope stability is good under the current blasting load, and the slope is in a stable state after blasting, which can provide a basis for the subsequent correction of mine blasting parameters.

Abstract:In order to solve the problem of surplus tailings stockpiling, ecological restoration is planned and implemented after the end of mining in the south of an iron mine. The hanging wall ore body is underground mining and application of sublevel open stopping with subsequent filling method. According to the engineering geological conditions of the south mining pit , the mining and filling scheme of the hanging wall mine, the dimensional numerical model of the south mining pit filling and underground mining is constructed to analyze the initial state of the computational model and simulate the filling process of the underground mining process of the hanging wall ore body. Firstly, according to the and mining technical conditions of ore body, stress, strain and plastic zone of roof under different lithology were studied and analyzed by numerical simulation method to evaluate the stability of stope and optimize the reasonable stops structural parameters. Finally, the influence of underground mining from backfill and no backfill in the south mining pit is simulated and analyzed. also, the stress and plastic zone changes of the open-pit slope and filling body in the hanging wall mine at different periods of underground mining are revealed. Through the comprehensive comparative analysis of the stress and plastic zone in different mining periods, it is suggested to strengthen the comprehensive monitoring of the stress and displacement of the open-pit slope, underground stope and roadway during the mining of the ore body in the -60m section.

Abstract:The large-diameter deep hole stage void field followed by filling is a safe and effective method for mining inclined very thick ore bodies, and a reasonable mining field structure parameter is a prerequisite for maintaining the stability of the mining field. The structural parameters of the one-step mining field were determined by the Mathews stability diagram method, and the stability of the mining field was investigated by the numerical software FLAC^3D based on the “one step at a time” recovery scheme. The results show that the structural parameters of the one-step and two-step quarries are both 45m×15m×30m. The filling body and the surrounding mine house do not reach their critical damage strength, and the quarry structural parameters are reasonable. The results of the study provide theoretical support for the safe recovery of inclined very thick ore bodies.

Abstract:A simplified model was constructed based on the geological background of a certain open-pit mine. First, limit equilibrium analysis method and SLIDE software were used to analyze the stability of the mining and waste dump slopes. Then, PFC discrete element software and FLAC finite element software were used to establish numerical models, simulating and analyzing the stress distribution, displacement changes, and the process of instability and failure of the waste dump and different sections of the mining slope. The two results are consistent with each other, and the internal mechanism of slope deformation and the law of instability and failure in the waste dump and mining area are obtained. Finally, based on the on-site engineering environment, it is pointed out that the slope of the 1# waste dump is basically stable, while the 2# waste dump is in an unstable state. In the unstable area, monitoring should be strengthened and appropriate reinforcement measures should be taken to prevent significant losses.

Abstract:The hydraulic fracturing method was used to conduct in-situ stress testing at a certain mine. Based on the measured data, the relationship between the magnitude of the in-situ stress and depth was analyzed, and the distribution law and variation characteristics of in-situ stress in the mine were obtained. The FLAC finite difference software was used to perform inversion simulation on the mining area, and the simulation results were used to verify the accuracy of the in-situ stress measurement results. The in-situ stress measurement results showed that the in-situ stress in the mining area was mainly composed of horizontal structural stress, with an average maximum horizontal principal stress direction of N 62.6°E. The maximum and minimum horizontal principal stresses and the vertical stress in the mining area all increased with depth. The average ratio of the maximum horizontal principal stress to the vertical stress was 2.42, and the average ratio of the minimum horizontal principal stress to the vertical stress was 1.49. The numerical simulation results showed that the maximum error between the inverted value of in-situ stress at the hole bottom monitoring point and the measured value was -13.9% of the maximum horizontal principal stress. The error was within a reasonable range, which verified the accuracy of the in-situ measurement data and the reliability of the inversion simulation, providing a data basis for subsequent work at the mine.

Abstract:In order to clarify the deformation and failure law of semi-coal rock roadway in thin coal seam, taking Chahe Coalmine as the engineering background, the fundamental cause of deformation and failure of semi-coal rock roadway is studied through theoretical analysis, and the failure and deformation law of semi-coal rock roadway under different coal-rock ratio is analyzed through numerical simulation. The results show that the deformation and failure of semi-coal roadway largely depend on the buried depth of roadway and the cohesion of surrounding rock, and the coal seam of two sides of roadway is the first to fail, and its failure depth is greater than that of other surrounding rock of roadway. With the increase of the proportion of coal to rock in semi-coal roadway, the plastic zone of surrounding rock becomes larger and larger, the range of high stress formed by surrounding rock becomes larger, and the horizontal displacement of two sides of roadway increases significantly. The peak displacement is mainly concentrated in the two sides of roadway coal seam, and the overall displacement of surrounding rock also increases gradually, especially the two sides of roadway coal seam. The increase of the proportion of coal and rock in semi-coal roadway is more likely to cause the roadway structure instability, the research results can provide some theoretical guidance for parameter layout of semi-coal roadway.

Abstract:The conventional surveying and mapping methods for open-pit mines use laser scanning to map the mining environment, which cannot provide a comprehensive view of the mine, resulting in reduced surveying and mapping effectiveness. Setting up a drone inclined photography route and using drones to collect field data of mines is the fundamental condition for mapping the overall view of mines. By utilizing oblique photogrammetry technology, a surveying and mapping model for open-pit mines is constructed to restore the mining environment in the form of a three-dimensional model, thereby achieving accurate surveying and mapping of open-pit mines. By using case analysis, it was verified that the surveying and mapping method has better surveying and mapping effect, and can map the overall view of the mine, which has high promotion value.

Abstract:The deformation and destruction of roadway surrounding rock is one of the main factors restricting the safe and efficient production of coal. Effective roadway surrounding rock deformation detection means and supporting technology are important guarantees for the normal mining of underground coal resources. In order to ensure the safe and efficient production of coal resources, it is particularly important to study the deformation and control technology of roadway surrounding rock. Combined with in-situ monitoring, theoretical analysis, data processing and numerical simulation, the lithology analysis of roadway surrounding rock was carried out, and the internal causes of roadway deformation were deduced. Then the roof separation instrument and borehole stress sensor were used for multi-source monitoring of roadway surrounding rock, and the monitoring data were analyzed remotely. According to the analysis results of data monitoring, a scientific and reasonable roadway surrounding rock control scheme is designed, and the control effect is tested by FLAC^3D numerical simulation method. The borehole stress gauge data show that the surrounding rock stress increases first and then decreases along the side wall away from the roadway. The data of roof separation instrument show that the mining influence does not cause serious roof separation phenomenon in the area of roadway stress increase. The numerical simulation results show that the surrounding rock control scheme can reduce the original deformation of roadway by 50%, so as to effectively control the deformation of surrounding rock. The study on monitoring and control of roadway surrounding rock deformation provides a theoretical basis for roadway surrounding rock deformation control.

Abstract:The acoustic emission (AE) technique was used to monitor the triaxial compression process of granite porphyry rock in an iron ore district, and the AE characteristics of the failure process of rock samples were obtained. The Mohr’s envelope was fitted by drawing the stress circle of granite-porphyry, and the cohesion of the sample was 18.68MPa, and the internal friction angle was 54.268°. By analyzing the stress-strain curves of granite porphyry under triaxial compression under different confining pressures and the characteristic curves of acoustic emission energy, event number and cumulative event number, it was found that the initial stress and the fracture breakthrough stress correspond to the first and second peak values of acoustic emission energy and event number. And the peak stress corresponds to the highest peak value of acoustic emission signal. Drawing the fitting line of characteristic stress intensity, it was found that the initial stress of fracture was less affected by confining pressure, and the fracture transfixion stress was greatly affected by confining pressure. The relationship between mechanical properties and AE parameters and rock fracture was obtained, which can provide reference for mining and engineering research with granite as surrounding rock.

Abstract:In this paper, the application of automated mining system in iron mines is studied, taking the Yianqianshan Iron Mine as an example. Firstly,the working principle and advantages of automated mining syatem were analyzed. The application of automated mining system in Yianqianshan Iron Mine is introduced in detail, and its application effect is evaluated. The research results show that the application of automated mining shovel and transport machine can improve the efficiency and quality of iron ore mining, reduce production costs, and have broad application prospects.

Abstract:A copper ore in Pakistan belongs to low grade sulphide ore, and three rougher, rougher concentrate regrinding, three cleaner flotation process was used to treat the ore. Optimum conditions, rougher grinding product size P₆₅=0.074mm, dosage of lime 1400g/t, dosage of collector AP 28g/t, and dosage of frother BK202 25g/t were confirmed, and regrinding product size was confirmed to be P₉₀=0.043mm. Final copper concentrate with copper grade 26.35% and copper recovery 89.34% could be obtained through closed flow sheet, besides 33.77% of gold and 20.15% of silver could also be recovered. The process is simple and the flotation index is good, which will provide technical guidance for the development and utilization of the mine.

Abstract:Experimental study is investigated in the rare-earth minerals in Sichuan, in view of the low recovery. And the “Bulk Flotation-High intensity magnetic separation” process was process was adopted. The flotation results indicated that, under conditions of the pulp concentration of 30%, NaOH dosage of 300g/t, silicate sodium dosage of 400g/t, H205+LD dosage of 300+300g/t, frother dosage of 50g/t, the rare earth concentrate was obtained by using of one roughing, four cleaning, two scavenging, and middles back to the flowsheet in turn. The rare earth flotation mixed concentrate was obtained with REO grade and operating recovery of 13.82% and 84.19%, respectively. The high intensity magnetic separation was used to removing barite and fluorite from the rare earth flotation mixed concentrate. The final concentrate REO grade, operating recovery and total recovery was 46.63%,89.22% and 75.11% respectively.

Abstract:For the crushing and dry separation processes, a three stage one closed circuit grinding and separation process is implemented. By combining the automatic control system with the performance of the process and equipment, a simple mathematical model is established for crushing and roller grinding dry separation. The feed rate is adjusted for different periods of material flow to achieve more grinding and less selection. Further classify and process iron concentrate and aggregates to achieve full process control from crushing and screening to magnetic separation. Segmented closed-loop control can achieve production with fewer people and ensure production stability.