CHINA MINE ENGINEERING

Abstract:Safe and efficient deep mining is an urgent problem facing the development of metal mineral resources in China. In recent years, remarkable progress has been made in China’s mining technology. However, owing to a relatively late start, there remains a certain gap compared to mining-developed countries. Through a comprehensive investigation of the current state of deep thick massive ore body mining technologies at home and abroad, this paper summarizes the characteristics of deep thick massive ore body mining in China. It introduces international case studies of deep thick massive ore body mining, and elaborates in detail on China’s practical experiences with backfill mining of these deposits. The aim is to innovate and establish a new mining model for mines of ultra-deep (exceeding 1000 meters) and 10 million tonnes per year production rate, prioritizing safety and green, low-carbon requirements, thereby providing guidance and reference for mines in China currently confronting the challenges of deep thick massive ore body extraction.

Abstract:This article takes the 113-01 fully mechanized mining face of Guotun Coal Mine as the research object, and uses a combination of numerical simulation and engineering practice to study the technology of passing through the old roadway in the mining face of deep mining mines. Based on FLAC3D numerical simulation analysis, it was found that when the untreated old roadway was pushed to a distance of 10 meters from the working face, the peak stress of the coal pillar reached 131.2MPa, and the plastic zone extended to 16 meters, resulting in a significant risk of roof collapse; After using EW-1 inorganic filling material with a water cement ratio of 6∶1 to fill the old roadway, the expansion range of the plastic zone is significantly reduced, and the stability of the surrounding rock is significantly improved. Combining roof grouting reinforcement with quality control measures for mining engineering, on-site practice has shown that the roof of the working face is intact during the passage of the old roadway, and no roof collapse accidents have occurred. The support resistance is stable, which verifies the effectiveness of the passage of the old roadway technology. This study provides technical reference for the safe passage of old tunnels in deep mine working faces.

Abstract:This study investigates the effect of length-to-diameter ratios (L/D) on dynamic mechanical properties of coal samples using Split Hopkinson Pressure Bar (SHPB) experimental device, using rectangular bullets in different impact velocity within 3.107-7.108m per-second to load and break the cylinder of raw coal specimen, the draw ratio of that in 0.5, 1, 1.5, 2 Researching the impact of the length of raw coal sample with on the dynamic mechanical properties. The results indicate that: ①due to the combination of the uneven distribution of the coal specimen self-contained bedding and strain rate effect, in the condition with relatively high impact velocity, strain-rate time-history curves showed two typical forms: the one is constant strain rate platform change gently, the other is the posterior part of constant strain-rate platform has obvious fluctuation; ② The samples with different draw-ratio show obvious strain rate effect, the shapes of the stress-strain curve of that range from 0.5 to 2 change in peaks , hills and polymorphism, showing different process of effects of elastic and plastic deformation; ③ With regard to the bedding structure of coal and the theory of SHPB test, whatever which are too long or too short , the samples are not suitable for studying the breakage features of the impact dynamic strain of coal. The sample with L=50mm is the best, that of 75mm is inferior.

Abstract:The Panjiatian Iron Mine is transitioning from open-pit to underground mining. To better design the shaft and tunnel engineering and address the potential rock-burst risks associated with deep ore body extraction, hydrostatic fracturing is used for in-situ stress testing, and energy accumulation simulation combined with rock mechanics parameters is employed for rock-burst prediction.The test principles methods of hydro-fracturing in-situ stress measurement are briefly described. The results show that the horizontal stress is predominant, the maximum principal stress of DH02 is between 7.52MPa and 17.86MPa; and Multiplex drill hole is between 7.08MPa and 15.8MPa; the direction of the maximum principal stress is NW. Analyse probable rock burst of the ore-body according to the measured monitoring results and rock mechanical parameters, the results show that there is approximately no rock burst in the ore-body, and suitable for tunnel. In-situ stress measurement provides scientific basis for the tunnel layout and roadway support design in Panjiatian Iron Mine．

Abstract:The evaluation of the caving ability of the Panjiatian Iron Ore Deposit is discussed by examining factors such as the ore body morphology, rock mass structure, intact rock strength, and the stress state of the original rock that affect the caving ability of the ore rock. The MRMR index classification method is used to conduct a quality analysis and evaluation of the industrial ore bodies and low-grade ore bodies of the Panjiatian Iron Mine. The MRMR value for the industrial ore bodies is 43, indicating a moderate caving ability, while the MRMR value for the low-grade ore bodies is 57, also indicating a moderate caving ability. Using the Laubscher caving chart method for caving ability evaluation, the hydraulic radius for the industrial ore bodies is found to be between 11m and 20m, and for the low-grade ore bodies, it is between 18m and 29.5m, with both values being relatively small. Through the study of the caving ability of the Panjiatian Iron Ore Deposit, it is concluded that the use of the natural caving method for mining is feasible.

Abstract:This paper constructs a dynamic evaluation system for the intelligent level of metal and non-metal mines, covering the whole production process, in response to the needs of intelligent mine construction. Through literature review, industry research, and referencing intelligent construction practices in related sectors, an evaluation model is proposed based on four dimensions: “intelligent production processes,” “effectiveness of safety management and control,” “data integration capability,” and “management innovation level.” The indicator layer refines these into 18 quantifiable metrics. A combined weighting method—integrating the Analytic Hierarchy Process (AHP) and entropy weight method—is adopted, with comprehensive weights calculated via linear weighting to achieve quantitative assessment. Results demonstrate that this system effectively identifies weaknesses in mine intelligentization, comprehensively and objectively reflects construction progress, provides tiered improvement recommendations for mining enterprises, supports high-quality industry development, and offers references for policy formulation.

Abstract:The traditional open-pit mines face significant challenges, including information silos, data integration difficulties, poor information flow, and extensive management practices. These issues result in weak comprehensive capabilities for informatization, visualization, and intelligent management and control. To address these issues, this study proposes and practices an Integrated Intelligent Management System of Mines based on real 3D and artificial intelligence (AI) technologies. The system innovatively integrates real 3D with AI to construct a digital twin management and control platform. This platform centers on unified spatio-temporal benchmarks for full-element mine information integration. It establishes a coordinated management framework covering “human-equipment-material-environment” full-elements in open-pit mines and implements an integrated intelligent management system platform. This integrated system platform combines a “The Intelligent Mine Command Large-Screen System” with “The Multiple Demonstration Applications”, covering core aspects of mine safety and production. Practical application at the Dalucao Rare Earth Mine in Dechang County, Sichuan Province, demonstrates that the system delivers significant improvements: mine production efficiency increased by approximately 27.78%, management efficiency improved by 25%, safety risks were effectively reduced by about 40%, and annual labor costs were reduced by 1.2 million RMB. These results provide a replicable scientific paradigm for intelligent mine construction. The system holds significant importance for promoting the green, safe, and sustainable development of mineral resource exploitation.

Abstract:Regarding the underground environment containing explosive gases and dust, the risk of explosion in the working environment is caused by ignition sources formed by non electrical explosion-proof equipment such as hot surfaces, mechanical sparks, and thermal reactions. This article proposes a method for suppressing ignition sources of non electric explosion-proof equipment based on D-S evidence theory and multi-sensor data fusion. It uses multiple sensors to collect information about the possible ignition sources that may form in the entire non-electrical system.It analyzes and evaluates the data characteristics formed by the working environment and different ignition sources to suppress the generation of non electric equipment ignition sources in underground environments containing explosive substances. Warning and initiating appropriate protective measures for potential ignition sources.It can ensure the safety of underground working conditions.

Abstract:The coal seam permeability in the mining area of the 111103 working face is poor, the pumping efficiency is low, the standard period is long, the regional geological conditions are complex, and the structural area is easy to accumulate gas, which causes gas accidents. In order to solve this problem, the comprehensive index method was used to analyze and evaluate the gas treatment measures of the working face, and it was found that the traditional pre-pumping borehole could not meet the requirements of the coal seam gas treatment. Numerical simulation analysis shows that there is still a blank zone for gas extraction for 12 months. The main factor that leads to the long period of gas extraction is the poor air permeability of the coal seam. The CO2 fracturing and permeability enhancement measures are used to carry out comprehensive gas treatment, and the maximum extraction concentration of low permeable coal seam after fracturing reaches 90%, and the attenuation is small, and the pumping can reach the standard after 6 months of pumping, and the extraction effect is remarkable. The tectonic area was continuously pumped after fracturing and permeability, and the effect was remarkable.

Abstract:According to the actual production and operation conditions of a mountainside tailings pond, two methods are used to analyze and compare the flood in the tailings pond. Under the premise of fully considering the influence of the backwater steel pipe in the tunnel, the discharge capacity of the drainage system in the tailings pond is analyzed and calculated in detail. Finally, the flood regulation calculation of the tailings pond is carried out by using the water balance method. According to the results of the flood regulation calculation, it is concluded that the flood control capacity of the tailings pond meets the requirements of the specification under the condition that the reservoir water level and the length of the dry beach are controlled according to the requirements and the drainage system is working normally. The purpose of this study is to provide technical support and guarantee for mining enterprises in the process of flood discharge and backwater facilities and safety flood management of tailings pond, and also to provide reference for fine management and standardized management of tailings pond.

Abstract:In order to solve the problem of large deformation of surrounding rock in shallow buried large section composite roof roadway, the 2301 return air roadway is taken as the research object. The reasons for the poor control effect of the original anchor mesh cable support surrounding rock in the return air roadway are analyzed. Targeted optimization support technology schemes mainly based on roof grouting and anchor mesh cable are proposed and applied in engineering. Using long anchor rods and cables to improve the strength of surrounding rock support, enhancing the integrity and deformation resistance of composite roof through hollow grouting anchor rod grouting, and further improving the surface protection strength through steel mesh and grouting methods. After on-site application, the deformation of the surrounding rock did not increase significantly after 120 days of completion of the 2301 return airway support. The maximum deformation of the roof, floor, and two sides were 191 and 117mm, respectively, indicating good control effect on the surrounding rock.

Abstract:In response to the bottlenecks of low efficiency, heavy pollution, and high costs in the traditional purification process of low-grade graphite ore, this study proposes a new flotation-alkali-acid composite gradient purification process, systematically investigating the evolution of impurity occurrence forms and the multi-stage synergistic impurity removal mechanism. By optimizing the ratio of flotation reagents and process parameters, the carbon content in the concentrate was increased from 6.8% in the raw ore to 88.6%; combined with the analysis of alkali fusion reaction kinetics, the quantitative relationship between the silicate decomposition rate and temperature and alkali concentration was revealed, and more than 80% of silicon impurities were removed through alkali fusion treatment at 700℃; a HCl-HF mixed acid synergistic leaching model was constructed to clarify the coupling effect of Cl^- complexing metal ions and HF directional etching of silicates, increasing the carbon content to 99.5%; finally, high-temperature purification at 2800℃ achieved a carbon content of 99.99%, with the ash content reduced to 30×10^-6. Multiscale characterization reveals that the composite process, by gradient removal of micron-scale gangue, nano-scale oxides, and atomic-scale light element impurities, maintains the integrity of the graphite crystal structure while ensuring surface cleanliness. This provides theoretical support and a technical pathway for the green and efficient utilization of low-grade graphite.

Abstract:This paper delves into the disaster-causing mechanisms and prevention strategies of mine vertical shaft hoisting system’s portal safety gate accidents. After analyzing domestic and foreign accident cases, it identifies mechanical failures, human-induced errors, and management deficiencies as key causes. It also systematically categorizes the structural and safety features of planar, vertical, V-shaped, and fold-over safety gates, presenting an inherent safety analysis framework and model selection optimization plan. Furthermore, it thoroughly assesses various drive modes (manual, pneumatic, electric, hydraulic, and cage-linked), comparing their principles, safety, and pros/cons, along with a guide for scenario-based drive selection. In closure and safety analysis, it originally proposes a hierarchical safety model of mechanical, electrical, and integrated locking, establishes the principle of direct detection of locking signals, and forms an enhanced interlocking control system for start-up, operation, and emergency braking. Finally, it scientifically defines safety-related quantitative indicators, sets inherent safety design standards, and envisions future directions like passive detection tech, intelligent standard systems, and safety integrity verification.

Abstract:This article summarizes the research process of composite flow resistance in slurry pipelines. Based on the research results of Durand, Ismail, Vasp and others, and according to the relative volume concentration CCA=C1VCV of slurry, the concept of boundary particle size between coarse and fine particles is proposed, and the formula for composite flow resistance in slurry pipelines is derived. This formula has a clear mathematical and physical concept, rigorous derivation, and simple calculation method, which can be used as a reference for slurry pipeline engineering design.