CHINA MINE ENGINEERING

Abstract:In view of the actual problems of increasing mining depth and possible increase of coal seam gas disaster risk in Donghuantuo Mine, the basic gas risk evaluation of coal seam such as the initial velocity of coal gas dispersion, the solidity coefficient of coal body, coal seam gas pressure and coal seam gas content of Donghuantuo Mine 7^#、8^#、9^#、11^# and 12^# coal seam was obtained through on-site measurement and laboratory tests, and the analytic-fuzzy mathematical comprehensive evaluation method (AHP-FCA) was used to carry out the coal seam gas risk evaluation. The results show that according to the analytic hierarchy method, the weight of gas outburst risk evaluation index can be determined, and it is concluded that coal seam gas pressure has the greatest impact on the gas outburst disaster in Donghuantuo coal, and it is suggested that the monitoring and management of gas pressure should be strengthened. Combined with the fuzzy mathematical comprehensive evaluation method, the comprehensive evaluation of the outburst risk of gas in each coal seam can be effectively evaluated. This evaluation method can quantitatively describe the gas hazard and visually reflect the degree of coal seam danger. The results of each coal seam showed that the outburst risk of gas in each coal seam in Donghuantuo Coal Mine was within a relatively mild range, and the possibility of gas disaster was low, and the prediction results were more consistent with the actual situation.

Abstract:The National Natural Science Foundation of China (NSFC) is an important source of funds to support basic research in China’s mining industry. The “13th Five-Year Plan” period (2016—2020) is an important upswing in the development of China’s mining industry. Using bibliometric visualization and knowledge mapping, the content and article outputs of NSF projects during 2016—2020 are analyzed, and the scientific research development in the mining field in recent years are summarized in terms of project types, temporal trends, key projects, key areas, and research hotspots. It can be seen that the funding of the NSF for the mining industry in general shows a stable growth trend, which have funded a total of 1936 mining-related scientific research projects of various types, with a total funding amount of 1.032 billion yuan, with research themes mainly distributed in the development and utilization of seabed mineral resources, mining method research and innovation, mining right management and value assessment, open pit mining process research, mining environment pollution and comprehensive management and protection, numerical simulation research and analysis of mining engineering problems, etc.

Abstract:Part of the mines domestically in China have basically completed the automation and information systems upgrading and modernization after years of integration construction. However, due to the lack of overall planning, single process and single system model is mostly adopted for implementation, with information islanding, business isolation, data value mining restrictions and other issues appearing between enterprise internal systems, under which circumstances, it is urgently needed to establish an integrated mine intelligent control system to achieve an in-depth integration between multiple systems of mine. Based on this background, this paper researches the construction scheme of integrated mine intelligent control system and discusses the architecture and methods to achieve integrated control of the various sub-production systems of mine at process level, business level and professional level. To establish an integrated intelligent control system for mines by applying industrial control, information network, digital twin and other advanced technologies, it can effectively solve the internal information islanding issue within mine, enable multi-business collaboration, tap the multi-dimensional value of mine data, and improve the overall intelligence level of mining enterprises.

Abstract:With the development of industrial Internet, artificial intelligence technology and big data technology, the mining industry ushered in a new round of rapid development period in intelligence construction, and some non-coal mining enterprises have gradually begun to explore the construction of intelligent mines. As a new generation of decision support system, intelligent decision support system has become an important part of current intelligent mine construction, and has been applied in the business scenarios of non coal mining enterprises. Based on the application of traditional decision support systems, this paper summarizes the key technologies of intelligent decision making, and proposes a set of intelligent decision support system architecture for non-coal mines based on intelligent decision making technology, and verifies the viability of the architecture through practical case application in an underground iron mine, which may have a certain guiding implications for building intelligent decision support system in other non-coal mines in the future.

Abstract:Based on the on-site situation of the caving of the MEMS inertial sensor protection device in the field blasting of Qidashan, this paper analyzes and studies the dynamic characteristics of the caving impact process and simulates and emulates the MEMS inertial sensor protection device using the finite element software Solidworks/Simulation, and derives the stress and strain clouds of the structural components of the MEMS inertial sensor protection device in the process of collapse impact, as well as the measurement data of the acceleration trajectory of different structural components as a function of time. On the basis of the simulation and emulation results, the system analyzes the structural components of the MEMS inertial sensor protection device affected by caving impact, thus providing an important reference and basis for the research on the performance of the MEMS inertial sensor protection device against caving and impact during mine blasting.

Abstract:In the process of mineral reserve estimation, we often come across the processing of samples with exceptionally high grades, and presently there are two common methods for processing exceptionally high grades, namely Traditional Multiplier Method and Mathematical Statistical Method. By taking the sampling data from the general exploration report of Laoyachao IV gold ore body (Phase II) as the research object, this paper employs the horizontal section method to conduct the resource estimation, and in view of the phenomenon where the geological grades obtained by using the multiplier method are usually undesirably high, it also discusses the lower limit value of exceptionally high grade and the reasonableness of the processing result from multiplier method and mathematical statistical method,. The research shows that the multiplier method lacks the theoretical basis of statistics and is only empirical, while mathematical statistics can well take into account the values of relevant statistical characteristics and has mathematical and statistical implications. After the mathematical and statistical processing, the sample grade variation coefficient has been reduced to some extent, the arithmetic mean of the samples is close to and less than the Sichel valuation, the weighted grade is reduced by 0.35g/t, the geological grade after processing is more consistent with the actual conditions of RoM ore, mitigating the influence of the extra high grade samples.

Abstract:A phosphate ore body belonging to a state company in Yichang has an average thickness of 17.71m and an average dip angle of 14.22°, which is a gently inclined massive phosphate ore body, with a loose structure of the ore bed and the roof, developed joints and poor stability; there are many dangerous rock bodies on the surface, which do not allow surface collapse; multiple poor and rich ore beds are distributed alternatively, which is not conducive to the classification and utilization of poor and rich ores. Overall, conventional mining is difficult. This paper describes in detail the panel layout, stoping sequence, secondary development and stoping process with room & pillar cut-and-fill method with subsequent filling under bolt and cable supporting roof and sublevel cutting roof. Production practice shows that this mining method has a larger production capacity than the original design, less secondary development quantity, high degree of automation, high safety factor, low ore loss and dilution rate, allowing for easy sectional mining, which can better meet the needs of mine production safety. The aim is to provide experience for the development of other similar mines.

Abstract:In order to understand the occurrence regularity of mine gas and evaluate the possibility of gas emission, the gas parameters of No. 8+9 and No. 15 coal seams in Duanwang Coal Mine were tested, and the coal seam porosity, adsorption constant, gas content, gas pressure and initial gas desorption rate were analyzed. The results show that: (1) the gas content of coal seam is relatively high. The gas contents of No. 8+9 and No. 15 coal seams are 3.68m³/t and 8.98m³/t respectively. The gas pressures are 0.24MPa and 0.49MPa respectively. (2) The initial gas desorption rates of No. 8+9 and No. 15 coal seams are 10.7mmHg and 13.2mmHg respectively, indicating that coal seams have the risk of outburst. Gas pre-extraction shall be carried out during coal seam mining and gas prevention measures must be formulated. (3) The flow attenuation coefficients of drill holes in No. 8+9 and No. 15 coal seams are 0.017d^-1 and 0.019d^-1, and the permeability coefficients of coal seams are 4.412MPa²·d and 9.000MPa²·d. The comprehensive evaluation shows that the gas in No. 8+9 and No. 15 coal seams can be emitted. The measured results provided the basis and foundation for gas management and comprehensive utilization.

Abstract:This paper takes Xing’an Coal Mine in Yuci, Shanxi Province as an engineering case, predicting the stoping working face, advancing working face, production mining area and the mine gas emission rate in the mine by different-source prediction model. The theoretical calculation and prediction results show that: during the stoping of No.15lower coal seam, the gas gushing quantity of gas emission from the stoping working face are mainly composed of extracting seam and then the adjacent seam. The compositions of the is mainly composed of open layer and then the adjacent layer. During the mining period of phases 1, 2, 3 and 4, the average gas emission from extracting seam accounted for 93.77%, and the from the adjacent seam accounted for 6.23%. For the gas emission compositions of stoping area, during the mining from phase 1 to phase 4, the average gas emission of stoping face, advancing face and mined-out area accounted for 56.88%, 19.99% and 23.13% respectively; and for the gas emission compositions of mine, during the mining from phase 1 to phase 4, the average gas emission of production mining area accounted for 83.38%, and of the mined area accounted for 16.62%. The prediction results can provide theoretical guidance for the application and engineering practice of gas extraction technology in Xing’an Coal Mine.

Abstract:Aiming at the practical problem of high gas concentration in the upper corner during the mining period of the fully mechanized caving face in Shiquan Coal Industry, the application practice of high-power directional drilling rig roof strike high-level drilling to extract gas in fracture zone is carried out. The practice shows that the directional drilling rig has the advantages of long duration of extraction effect and high utilization rate of borehole. Through the 30108 fully mechanized caving face layout coal seam roof to long drilling, drilling length of about 400m, drilling depth of 36~48m, the drilling gas concentration within the basic control of 20%; the gas concentration in the upper corner of the working face before and after the drilling is 0.78% and 0.57% respectively, and the gas concentration is reduced by 26.9%. The test results provide meaningful reference and reference value for similar gas control technology.

Abstract:In view of the gas control problem of Donghuantuo 3095 working face, through the collection, analysis and calculation of gas parameters during the excavation of the working face, the comprehensive gas control plan during the mining period of the working face is formulated in advance, which can simultaneously implement the gas control project during the excavation and installation process to ensure that the gas control measures during the mining period are in place. At the same time, by analyzing the effect of gas control during mining, the specific parameters of gas control measures can be further optimized, so as to significantly improve the effect of gas control and avoid the gas concentration in the working face exceeding the limit. The research results show that after the implementation of the gas comprehensive control measures of the combination of pipe drainage at the upper corner and water injection at the working face, the gas concentration at 3095 working face and the upper corner is controlled below 0.21%, and there is no obvious gas accumulation during the mining, which can effectively ensure the safe and efficient mining of Donghuantuo 3095 working face, and provide important reference and reference for the gas comprehensive control of working faces in similar mines.

Abstract:In order to ensure safety production, the monitoring of the goaf is based on the analysis of the existing goaf monitoring system. The system has real-time monitoring data display, automatic alarm, automatic data storage and playback. Compared with other goaf monitoring systems,the monitoring system has the characteristics of diversified monitoring means, low monitoring cost, high forecast accuracy and strong scalability.

Abstract:Frequency control technology has been widely used in various fields of society, not only can play an obvious energy-saving effect, but also can meet the needs of various processes in production, bringing very considerable economic and environmental benefits for enterprises. This paper describes the necessity and advantage of frequency control of semi-autogenous mill, and the research and analysis are carried out combined with the relevant research results and application cases. It is hoped to provide some reference for relevant personnel to popularizing and applying mill frequency conversion speed regulation technology.

Abstract:Water prevention and drainage is an important part of mine safety production. There were two times of flood damage during the production of an open-pit mine. After doing a lot of field research, the design for water prevention and drainage was carried out accordingly. In the implementation of the scheme, measures such as filling, blocking, dredging, prevention and drainage are carried out, and the feasibility is confirmed in the actual operation of mine water prevention and drainage.

Abstract:The automatic driving technology of underground mining trackless vehicle is always a key link that affects the realization of automation and intelligence in mines. In this paper, based on the analysis and research of the application environment and technical difficulties of the automatic driving system of underground mining trucks, the overall design scheme of automatic driving system is put forward, and the key technologies in the application are studied and discussed. The study results show that the issues of the safety of mine drivers and production efficiency can be solved by the technologies of automatic driving system drive-by-wire upgrading, intelligent perception, positioning, communication and mining truck integrated dispatching, and these technologies also effectively improve the intelligent level of mine equipment.

Abstract:The Liuhuangshan Cu-Pb-Zn polymetallic mine is located in the syncline fold belt of the South Tianshan. After more than ten years of mining, the ore body shape is gradually clear, but its genetic type is unknown. Based on the mineral exploration in the past two years, previous geological exploration data and regional data, this paper discusses the metallogenic model of the Liuhuangshan Cu-Pb-Zn polymetallic mine, combined with the data of chemical exploration results and the diagenesis and metallogenic laws, from the aspects such as geologic features of the deposit and the ore body, determines its genetic type, and provides ideas for similar type prospecting. The genetic type is preliminarily considered to be the “medium-low temperature hydrothermal filling and metasomatism” type Cu-Pb-Zn polymetallic deposit related to magmatic activity in the late caledonian movement.