CHINA MINE ENGINEERING

Abstract:This research simulated the super-large-scale continuous panel multi-level mining and filling process of a super-large iron mine, and the stress perturbation law was focused on. Results show that the overlaying effect of muti-level mining has negative effects on the stability of the 26m-wide pillar apparently.There are stress-releasing area between two levels and obvious stress concentration areas below Level -580m. The result can be a good reference for continuous panel super-large-scale mining and stress-releasing mining in deep mine.

Abstract:In a super-scale and deep mine, the ore body is extremely thick and large. Extra large strip ore pillars are arranged between the panels. In this paper, the numerical simulation method is used to conduct a comparative study on the stress characteristics and plastic zone distribution of different de-stress schemes applied on the strip pillar. The effect of different de-stress schemes was revealed. A recovery method of strip ore pillar is put forward, which is “the first step: drift de-stress stoping; the second step: medium-long hole or long hole stoping with backfilling”. Its results can provide reference for de-stress mining under similar mining conditions.

Abstract:Mining with block caving is extremely severity for rockmass occurrence characteristics, and rockmass caveability directly affects caving rate and secondary fragmentation of block caving mines. It is a vital technology to realize ore and rock pre-conditioning by increasing internal fractures with artificial auxiliary fracturing, which is currently a routine production process of block caving mines abroad. Based on Tongkuangyu mining project of the first block caving mine in China transferring to the deep, a detailed investigation of rockmass occurrence characteristics and a field test on rockmass pre-conditioning by hydraulic fracturing were carried out. The results show that rockmass at the start caving area of No. 5 orebody in Level 410m of Tongkuangyu mine is hard rock with medium to less integrity, rockmass quality classification is II to III and rockmass caveability is moderately to hard, which would result in caving mining with medium broken and more bulk. Detailed investigation of rockmass occurrence characteristics is the basis for in-depth understanding of rockmass caveability. Borehole wall images before and after preconditioning tests by hydraulic fracturing were obtained and newly generated hydraulic fractures were observed, which could effectively improve the degree of rockmass structure development. Based on analysis of caving front monitoring and drawpoint fragmentation distribution, a more than 3 times increase in caving rate and a 58.3% reduction in secondary fragmentation were achieved in production period of the start caving area, which provide a solid support for steady convergence of production capacity in transition period of mine to the deep. The technology of rockmass pre-conditioning by hydraulic fracturing and related equipment system were initially formed which could support a further development of modern block caving mining in China.

Abstract:As the throat project of deep mining in the mine, the construction period of the shaft controls the whole mine construction period, and the safety and stability of its service period restricts the normal safety production of the mine. Based on the auxiliary shaft project of Sanshandao gold mine, this paper studies and discusses the support concept, support scheme and construction innovation of large-diameter deep-buried shaft with diameter of 105m and buried depth of 1915m. Through in-depth study of domestic and foreign support theory, breaking through the traditional design concept, adopting the design concept of new process pressure relief and making full use of the role of surrounding rock, this paper studies the support scheme of large buried deep shaft, and discusses the innovation direction of deep well construction. The research results of this paper can provide reference application for the support design of bottleneck engineering in deep development and utilization, and provide important reference for the construction technology of deep well and related deep well engineering below 2500m.

Abstract:Aiming at the problem of low accuracy of predicting particle peak velocity by traditional empirical formula in electronic detonator initiation technology, this paper classifies the particle peak velocity according to different hole types according to the characteristics of electronic detonator blasting construction, and proposes a piecewise particle peak velocity prediction method, which is combined with metal mine tunnel blasting. The results show that the traditional Sadowski empirical formula is not suitable for predicting the peak particle velocity of electronic detonator blasting; After sorting the holes according to the delay time, the peak particle velocity can be predicted by Sadowski empirical formula. The part with the largest predicted value of each type of blast holes under the proportional distance charge is selected. Based on this, the combined curve has a better fitting effect.

Abstract:The article summarizes and analyzes the current situation and problems of common concentration control systems for filling slurry preparation, proposes a concentration feedforward stable control process for filling slurry preparation based on stirring torque signals, and elaborates on its technical implementation approach in detail, in order to provide guidance and reference for the large-scale and high-flow stable preparation in mines.

Abstract:In order to explore the feasibility of cemented filling classified tailings in an iron mine in Anhui province, based on the analysis of physical and chemical characteristics of test materials, the flocculation settling test of classified tailings, the strength test of backfill and the fluidity test of filling slurry were carried out. The results show that the optimum parameters for density of classified failings is 30% mortar concentration and 30g/t flocculant addition. Under the same ratio, the strength of classified tailings at each age is lower than that of whole tailings. In order to meet the requirements of mine strength, classified tailings filling needs to increase the ash sand ratio from 1∶12 to 1∶10 when the mass concentration remains unchanged. The flowability of classified tailings is lower than that of full tailings, but there is little difference in the whole, and both can meet the requirements of mine filling. The comprehensive determination of the critical flow state concentration of the classified tailings slurry test under various ash sand ratio conditions is not less than 70%. The research results provide data support for the application of graded tailings in mine filling.

Abstract:Against the background of solid waste disposal and comprehensive treatment of open-pit backfilling in a certain mine, due to the fact that the unclassified tailings of the mine are fine faction tailings and contain S and clay minerals that have a negative impact on the strength of the filling body, in order to select a cementitious material that is more suitable for the full tailings of the mine, select cement and glue-powder as two types of cementitious materials to contact the experimental study on the performance of filling slurry, results indicate: although SBT filling body have better characteristics at the aspect of bleeding and settling compared to glue-powder, in terms of the two key indicators of filling strength and fluidity, the performance of glue-powder is superior to that of cement and the cost is lower, showing that glue-powder is more suitable for solid waste disposal and backfilling treatment in this mine; through sensitivity analysis, it can be concluded that the strength of cemented by glue-powder is most sensitive to the ash sand ratio, followed by the curing age, and finally the slurry concentration.

Abstract:Based on the construction of main shaft hoisting system in Sishanling Iron Mine, a ten-million-ton “double super” mine, this paper comprehensively discusses the research work carried out in determining the parameters of main shaft hoisting system and the new technology and equipment adopted in design and construction from the aspects of main shaft hoisting system scheme, shaft hoisting operation safety clearance research, large-scale hoisting technical equipment application and large-scale main shaft tower layout. The construction of main shaft hoisting system in Sishanling Iron Mine will have a strong benchmark demonstration significance for the construction and implementation of high speed and heavy load hoisting system in similar mines in China.

Abstract:A 60 million tons/a scale mine abroad is located in an inland area. The ore body is narrow and far from the mineral processing industry site, with steep terrain and natural slopes. The transportation of ore in this project is characterized by high volume, long distance, and high difficulty in transportation. For large-scale mines, belt conveyors play an extremely important role in the production process due to their advantages of large transportation capacity, long-distance transportation, high degree of automation, and the ability to achieve continuous transportation. At the same time, due to the increasing distance required for conveying, single section of belt conveyor is difficult to meet the overall requirements of bulk material transportation in mines. Belt conveyor systems with large capacity and large angle relay transportation are widely used. This article draws on the production data of the system of existing mining belt conveyor to analyze and calculate the reliability and energy consumption of the belt conveyors system against the background of this large mine, providing reference for similar projects.

Abstract:The Xi anshan Iron Mine is a super large scale mine, and the use of TBM to construct belt slope and ramps is the first application of this technology in domestic underground iron mines. There are significant differences between TBM construction and drilling and blasting construction in terms of exploration, design, and construction. Based on the TBM construction of iron mine shaft engineering, combined with equipment performance and development system process requirements, this article innovates the application of inclined shaft route planning, curve radius selection, starting site design, starting and receiving section support, normal section support selection, roadway floor treatment, and opening design form. At the same time, combined with the problems encountered in project design and construction, an analysis and discussion were conducted on the technical requirements for TBM construction survey applicable to mining engineering, the selection of construction plans, and the improvement of TBM construction section utilization rate.

Abstract:With the increase of the mining depth of metal mines, the high ground temperature is becoming more and more serious, However, our mines have insufficient experience in heat hazard control, lack of individual protection and training, and less application of effective mechanical refrigeration technology. Therefore, it is important to strengthen the research on the safety technology of heat damage prevention and control in deep well metal mines. This paper will analyzes the influence of thermal environment on operators and production efficiency in deep mine, summarizes the comprehensive measures for heat hazard prevention and control, including ventilation system optimization, heat source control, individual protection, compressed air refrigeration, mechanical refrigeration, etc., and will lists the typical applications of mechanical refrigeration and cooling technology in two typical deep mine in South Africa and Australia, which can be used as reference for other deep mine.

Abstract:This article introduces the main difficulties faced by the ventilation system of metal and non-metal deep well mining, discusses the key issues of deep well ventilation, and explores the development of engineering implementation plans. The key to deep well intelligence lies in establishing a unified environmental monitoring and evaluation system, dust reduction and refrigeration system, comprehensive judgment system for ventilation energy consumption, and intelligent control system for ventilation structures. Based on different mining process conditions, reasonable mining engineering design is carried out to improve the effective utilization rate of air flow and cooling capacity. The implementation of deep well intelligent ventilation engineering will be the guarantee for the sustainable, efficient, and safe development of metal and non-metal mines.