CHINA MINE ENGINEERING

Abstract:In order to study the effects of strain rate and water content on energy dissipation of frozen clay, the energy dissipation characteristics of frozen clay under different impact velocities (4~10m/s) and different water content conditions (9%~18%) were investigated comprehensively by means of ?50mm Split Hopkinson Pressure Bar kinetic test. The test results show that: (1) from the perspective of dissipation energy, the energy absorption process of frozen clay damage is divided into three stages: slow growth, rapid growth and stabilization; there is a positive primary function correlation between dissipation energy, reflected energy and transmissive energy and incident energy (R²＞0.94), and there is also a linear positive correlation between incident energy, reflected energy, transmissive energy and dissipation energy and average strain rate (R²＞0.87); with As the water content increased, the energy reflection coefficient, energy transmission coefficient and energy dissipation coefficient showed decreasing and then increasing, increasing and then decreasing trends, respectively. The results of the study provide reference for the construction of blasting projects in permafrost areas.

Abstract:The consolidated surface stacking technology of tailings provides a new way to solve the tailings treatment and the reclamation and backfilling of open pit. Based on the engineering background of Dagushan Iron Mine of Anshan Iron and Steel Group, this paper studies the slurry ratio of backfill body and the mechanical properties of the backfill body formed. After determining the ratio of filling slurry used in the pit filling treatment, COMSOL numerical simulation software was used to evaluate the stability of the pit bottom cover structure in the filling process from two aspects of stress evolution process and displacement distribution. The results show that the existing mine filling treatment scheme can meet all requirements.

Abstract:This article introduces the content of the research on the stability of the existing slope of Maoboxi Stone Mine in Shaoxing County, and reveals the application method of slope analysis software in mining slope analysis, which is modeled after Slide 6.0. The Slope 6.0 slope analysis software can directly display the calculation results of slope safety factors, but different calculation results can be obtained under different working conditions or using different analysis methods.. The method used in this article has certain reference significance for other similar mines.

Abstract:The basic L-G graph theory does not take into account the possible cost advantages of underground mining, and there are certain limitations in the boundary optimization of open-pit to underground mining. Based on the analysis of the economic and reasonable stripping ratio calculated by the price method and the reserve profit comparison method, and combined with the NPV Scheduler software, this paper studies the method of boundary optimization of open-pit to underground mining, and verifies the rationality of this method through engineering examples. The research results have certain guiding significance for the determination of mining boundary of open-pit to underground mines.

Abstract:For field production processing problems, the method of copper selective flotation-middling regrinding separation was obtained as a preferred method for Anhui high-sulfur copper ore, which based on mineralogical property analysis and optimization test of separation system conditions. The results show that, compared with the flow of copper selective flotation which used middling regrinding-returning in order, the optimized separation process could decrease the accumulation of procedural middling, improve the separation efficiency of ore, reduce the impact of floatable and fine gangue, increase the recycling ratio of copper, and improve the concentrate quality. It showed that the copper accumulation of the during middling decreased by 3% and 11% and the total copper recovery ratio increased by 0.6% and 0.2% of the Sample 1 and Sample 2, respectively, by using the middling regrinding separation than that of the middling regrinding returned sequentially under laboratory conditions. Moreover, the recovery ratio of the copper roughing flotation increased more than 5% for Sample 1, and the content of the copper in copper concentrate increased more than 3.6% for Sample 2. This work provides a reference for high efficiency separation of the complex dissemination high-sulfur copper resources.

Abstract:An open pit mine is composed of two adjacent south and north open pits. The lowest mining level of the north open pit is -350m, and the south open pit is -50m, and the south open pit is planned to be closed after one year. In order to achieve the ecological restoration of the south open pit, it is planned to carry out the tailings cementation filling after the south open pit is closed. In order to ensure that the filling of the south open pit will not affect the normal and safe production of the north open pit, it is necessary to analyze the stability of the slope during the filling treatment of the open pit. Geo-Studio software is used to analyze the stability of the slope before and after the filling of the south open pit, and different working conditions such as the thickness of the filling revetment, the stacking height, groundwater, and seismic load conditions are considered. The research results can provide a basis for the filling treatment of the south open pit and the safety production of the north open pit.

Abstract:Based on the current gold market price, the industrial index of a low-grade gold deposit in Jinchang, Gansu Province is demonstrated. The geological scheme method is used to simulate the mine production process flow, and the four sets of index schemes are calculated to select the industrial index suitable for the deposit from the aspects of resource utilization and economic benefits.

Abstract:On the basis of establishing the model equation of gas flow in mining area, taking 24312 working face of Xinjiang 1930 Coal mine as the engineering background, the gas extraction effect of three parameters of different well location, drilling diameter and drilling depth during coal mining was simulated. The calculation results show that the flow rate and concentration in the extraction well are obviously different under different working conditions. The maximum gas extraction amount can be achieved under the condition that the extraction period is 360d, the local well is about 30m away from the side wall of the return air roadway, the end hole is located in the middle of the coal seam, and the drilling diameter is 210mm. The numerical simulation results were used to guide the ground well construction of 24312 working face. After 180 days of operation, the gas concentration in the return air roadway decreased to 60% of the previous concentration, and the gas concentration in the upper corner decreased to 52%. The gas concentration on both sides decreased significantly, eliminating the threat of gas overrun on the working face. The simulation results can provide reference for the layout of surface Wells in similar mining areas.

Abstract:Hongling coal mine is a coal and gas outburst mine.In order to determine the sensitive index and critical value of outburst prediction in working face, the drilling cuttings quantity (s) , initial gas emission velocity (q) and drilling cuttings gas desorption index (Δh₂) under different adsorption gas pressures in coal seam are simulated by experiments, the relation between prominent prediction index and gas pressure is obtained.In this experiment, the critical value of coal face prediction index is determined based on the critical value of gas pressure 0.69MPa in regional prediction index of Hongling mine. Finally, the sensitive index and critical value of outburst prediction in No.2-1 coal face are determined by determining the sensitivity of prediction index according to the dispersion between the coal seam gas pressure and the prediction index of working face. The results of this experiment can be used as an important basis for mine outburst prevention work.

Abstract:In view of the dynamic disaster accidents such as roof caving and coal wall spalling in fully mechanized mining face and mining roadway during the mining process of lower coal seam in close distance coal seam. Based on the engineering background of 14101 fully mechanized mining face in close distance coal seam group, this paper studies the roof caving characteristics and weighting law of lower coal seam mining in close distance coal seam group by using UDEC numerical simulation software, and obtains the weighting law of lower coal seam mining roof. The simulation results show that the weighting intensity is low, but the weighting is frequent, which leads to the occurrence of roof disaster accidents. The roof control measures in normal and special periods of working face are put forward. Through the monitoring of roof pressure on site, the roof weighting law is verified, and the corresponding stability control measures are beneficial to the stability control of roof. The research has certain reference value for the roof stability control of similar working face mining.

Abstract:Through the active advance support strengthening form of adding grouting anchor cable + anchor cable to the mining roadway of 153307 fully mechanized caving face instead of the support form of single hydraulic prop, the passive support is changed into active support, the roof stress of the roadway is reduced by 32.1% and 7.2% in the vertical and horizontal directions respectively, and the roof subsidence value is reduced by 107mm. The plastic zone is reduced by 1m. The active support is used to strengthen the integrity of surrounding rock, which realizes the safe and efficient production of mine, and provides scientific guidance for mines with similar conditions.

Abstract:In this paper, the data of comminution characterization test of molybdenum ore with complex components are analyzed, and the key design parameters are determined, then the key equipment in SABC comminution process is simulated. By simulating seven different operating conditions, the influence of ore property change on grinding system productivity in mining process is predicted, which provides technical support for the future production adjustment.

Abstract:Technical and economic comparison between SABC and HPGR process was conducted for Shandake copper mine new plant. The results indicate that the investment of HPGR process is 5674 thousand dollar higher than SABC process. Energy consumption for treating one ton of ore of SABC process is 2.78kWh/t higher than that of HPGR process. The operating cost of HPGR process is 0.54 dollar lower than SABC process when treating one ton of ore. Net present value of SABC process is 7086 thousand dollar higher than that of HPGR process when internal rate of return is 8%. In the long run, HPGR process has more better economic benefits for Shandake copper mine.

Abstract:China’s carbon emissions account for about one third of the world’s carbon emissions, including more than 70% of the carbon emissions generated by coal consumption, as carbon neutrality has become a major strategic goal of the country, then the coal industry emission reduction measures must be the most important. China’s relevant institutions and scholars predict that even after carbon neutrality, the demand for coal will still reach 1.2 billion to 1.5 billion t/a, so the coal industry must explore a green development road. According to our country coal distribution area and ecological geological characteristics, the relationship between reduction should be throughout the whole life cycle of coal is put forward, that is, from the coal exploration, mining, coal and coal chemical industry, ecological restoration, layout of new energy, into the carbon market, innovating the mode of government regulation and a series of measures to reduce emissions or increase carbon sinks, to achieve carbon neutrality.