Mining Engineering Commons^™

Simulation Optimization And Applications Of Pressure-Preserved Triggering Device For Coring In Deep Coal Mines, Shi Xiaojun, Li Minghui, Liu Guikang, You Zhenxi, Guo Lihua, Hou Lele, Zhao Xiang

Coal Geology & Exploration

The pressure-preserved controller is the core component of pressure- and gas-preserved coring equipment used in deep coal mines. Its pressure-preserved capability and sealing performance are the key to pressure- and gas-preserved coring technology. Given that the existing pressure-preserved controller exhibits low initial sealing specific pressure and poor sealing performance when its initial sealing force is provided only by gravity, this study innovatively designed a pressure-preserved triggering device for coring, aiming to provide initial sealing specific pressure required for the sealing of the pressure-preserved controller. Then, this study conducted numerical simulations of the operating process of the triggering device using the …

Development Of Self-Locking Transfer Mechanism For Coal Samples From Pressure-Preserved Coring In Deep Mining, Zhu Pengfei, Li Jianan, Li Ju, Fu Chenghang, Ye Banghua

Coal Geology & Exploration

Pressure-preserved coring technology can directly store the collected deep coal samples at the bottom of the hole, so as to minimize the gas loss during the coring process. Besides, pressure transfer and testing of the pressure-preserved rock core is a technical prerequisite for the accurate determination of gas content. Then, how to achieve the precise docking from pressure-preserved coring to pressure transfer and testing has become a key technical difficulty that needs to be overcome urgently. Therefore, the research was carried out around the self-locking transfer mechanism, which is the core component of the docking transfer between the pressure-preserved coring …

Closure Trajectory Model Of Pressure-Preserved Controller For Coring In Coal Seam Surface Well, Guo Da, Zhang Yiwei, Wang Dingming, Fang Xin, Yang Bengao, Guo Lihua, Hou Lele, Zhao Xiang

Coal Geology & Exploration

The traditional method of coal exploration is to obtain coal samples using an open coring tool and estimate the gas loss through theoretical calculations. However, the measured gas content of these coal samples is generally low, significantly impeding the development and utilization of coalbed methane and compromising the safety of coal mining operations. To meet the demands of deep coal exploration, an innovative pressure-preserved coring tool was specifically designed for the coal seam surface wells. This tool has a total length of 6.7 m and can extract a 3 m long pressure-preserved coal core sample at a single time. In …

Fractal Theory-Based Permeability Model Of Fracture Networks In Coals, Xia Binwei, Liao Chuanbin, Luo Yafei, Ji Kainan

Coal Geology & Exploration

Fractures in coal reservoirs, which act as the major seepage pathways for coalbed methane (CBM), determine the permeability and CBM productivity of coal reservoirs. Research on the relationships between fracture structures and reservoir permeability is of great theoretical and practical significance for the accurate prediction of CBM productivity. Based on the classical cubic law-based permeability model, as well as the fractal theory, fracture network structures, and effective stress, this study built a permeability model containing complex bending fractures, which was then combined with the S & D (Shi-Durucan) model to build the permeability model of fractured coals under the action …

A Method For Classification Of Surrounding Rock Based On The Excavatability Performance And Adaptability Of Tunnel Boring Machines And Its Applications, Liu Jiawei, Zhang Sheng, Chen Zhao, Yang Zhanbiao, Ji Panjun, Wei Yonghui

Coal Geology & Exploration

The varying geological conditions of the surrounding rocks of coal mine roadways influence the wide application of full-face rock tunnel boring machines (TBMs). Therefore, accurately assessing the excavatability of rock masses in coal mines and the rock adaptability of TBMs is crucial for the efficient operation of TBMs. Based on the evaluation results of the parameters and excavatability of rock masses, this study built a classification model for rock mass excavatability using the technique for order preference by similarity to ideal solution (TOPSIS). Furthermore, combining the correlation analysis between the [BQ] values of different geological conditions and the utilization ratio …

Drillability And Mechanical Parameters Of Laser Hot Cracking Sandstones, Yang Lei, Yang Bengao, Liu Junjun, Zhou Xuemin, Xie Jing, Wang Chen, Guo Chenchen, Gao Mingzhong

Coal Geology & Exploration

Over recent years, shallow coal resources that can be easily mined have been gradually exhausted. As a result, conventional drilling techniques tend to face challenges such as low rock-breaking efficiency, high drilling costs, and environmental pollution in the exploration and exploitation of deep coal resources. Therefore, there is an urgent need to introduce a new auxiliary rock-breaking technique for drilling. Focusing on the new laser-assisted rock-breaking technology, this study systematically conducted mechanical and drillability tests on sandstones after laser irradiation for different durations, aiming to explore the temporal and spatial evolution of the temperature field of hard sandstones, the propagation …

Physical And Mechanical Properties Of Thermal Insulation Materials For In-Situ Temperature-Preserved Coring Of Deep Rocks, Xue Shouning, He Zhiqiang, Li Cong, Yu Bo, Lu Xuelian, Liu Wenyue, Yang Jianping, Wei Zijie

Coal Geology & Exploration

High temperature affects deep coal mining and other engineering activities. However, conventional coring methods for terrestrial hard rocks lack temperature-preserved measures, ignoring the effects of temperature on the physical and mechanical properties of rocks. Consequently, the parameters obtained are subjected to distortion, affecting the safe and efficient mining of resources such as deep coals. To make breakthroughs in the development of in-situ temperature-preserved coring technologies for deep rocks, this study proposed using the hollow glass microsphere/epoxy resin (HGM/EP) as thermal insulation materials and the physical and mechanical properties. The results are as follows: (1) With an increase in the HGM …

Research Advances On The In-Situ Pressure-Preserved Coring And Gas Parameter Determination For Deep Coal Seams, Xie Heping, Cui Pengfei, Shang Delei, Fan Dong, Chen Ling, Yang Mingqing, Du Lin, Gao Mingzhong

Coal Geology & Exploration

The in-situ gas pressure and content of coal seams are critical for the safe production of deep coal mines and the accurate evaluation of coalbed methane resources. To address the technical challenges of accurately determining in-situ gas content in deep coal seams, this study proposed brand-new principles of in-situ pressure coring and the tests of in-situ gas content and pressure. It also derived a calculation method for in-situ gas content in coal seams and a method for determining the in-situ gas pressure while considering the effects of moisture content and multiple gas components. Given the in-situ stress environment deep in …

A Preliminary Study Of Pressure-Preserved Coring Calculation Principle And Method For In-Situ Pressure In Deep Coal Seams, Cui Pengfei, Gao Mingzhong, Shang Delei, Li Jianhua, Chu Peng, Song Jie, Li Yongcheng, Hao Haichun

Coal Geology & Exploration

The accurate acquisition of in-situ gas pressure in coal seams is a key link in the chain of the prevention and control of gas disasters. Presently, it is still necessary to explore accurate, low-cost, and time-saving methods for determining gas pressure. Based on the in-situ pressure-preserved coring for deep coal seams, this study proposed a calculation method for in-situ gas pressure in deep coal seams and developed the calculation process. Using the constructed numerical model of the gas pressure evolution in the pressure-preserved space, this study verified the reliability of the proposed method by comparison with the theoretical and numerical …

Influence Of Gas Components On The Determination Of Gas Pressure In Coal Seams Under In-Situ Pressure-Preserved Coring, Chu Peng, Shang Delei, Li Jianhua, Ma Shaoming, Zhu Guodong, Cui Pengfei

Coal Geology & Exploration

Determining the pressure and content of coal seam gas based on pressure-preserved coring is an effective method for quickly and accurately calculating gas parameters. Coal seam gas is a multi-component gas mixture dominated by methane. Given that coals show different adsorption capacities for different gases and that the components in the mixed gas exhibit different partial pressures, the proportions of gas components can influence the calculation results of the content and pressure of coal seam gas. To accurately determine the in-situ gas pressure in coal seams based on the pressure-preserved coring, this study investigated the influence of gas components on …

Exploring The Wetting Mechanism Of Surfactants For Coals Based On Molecular Simulations, Tong Yanjun, Yang Zundong, Song Jie, Li Yongcheng, Liu Yiting

Coal Geology & Exploration

With a gradual increase in the depth and mechanization degree of coal mining, secondary explosions of gas and coal dust have become increasingly severe. Chemical dust suppressants such as surfactants can reduce these explosions by effectively inhibiting the generation and diffusion of coal dust. To explore the inhibition mechanism of nonionic surfactants for hydrophobic coal dust, this study analyzed the basic physicochemical properties of typical hydrophobic coal dust at a depth of 1050 m using FT-IR, XRF, and XRD. This study built a molecular structure model of coal dust by combining test techniques such as EA, XPS, and ¹³C …

Sealing Performance Analysis And Structure Optimization Of Pressure-Preserved Controller For Pressure-Preserved Coring In Deep Coal Mine, Wang Tianyu, Li Jianan, Zhang Yiwei, Li Ju, Xie Heping

Coal Geology & Exploration

As the pressure-preserved controller is a core component of the deep coal in-situ pressure-preserved coring device, its sealing design plays a decisive role in the effect of pressure-preserved coring. In order to obtain the optimal sealing structure, a two-dimensional axisymmetric nonlinear contact model was established for the sealing structure of the pressure-preserved controller. On this basis, the effects of different groove design, cone angle selection and friction coefficient on the sealing performance were analyzed by orthogonal test method. Meanwhile, the stress changes of the sealing ring under different closing stages and medium pressures were studied. The results show that: the …

Pressure Relief Mechanisms And Effects Of Liberation Seam Mining In 1000-M-Deep Coal Mines: A Case Study Of The Huafeng Coal Mine In Tai’An, China, Gao Yanan, Zhang Yao, Zhang Defei, Zhang Yudong, Zhao Weidong, Yu Liyuan

Coal Geology & Exploration

Liberation seam mining serves as an important approach to the prevention of deep dynamic disasters such as coal and gas outbursts, as well as rock bursts. Based on the Nos. 2613 and 2412 mining faces of a 1000-m-depth coal mine in the Huafeng Coal Mine in Tai’an, Shandong, this study investigated the engineering scientific issues such as the pressure relief mechanisms and effect evaluation of liberation seam mining through physical and numerical simulations. As a result, it determined the movement law of overburden strata and the characteristics of underground pressure after the mining of the liberation seam and ascertained the …

Remote Sensing And Gis Based Approach To Evaluate The Impact Of Stone Quarrying And Crushing Activities On Land Resources, R. S. Chaurasia, S. N. Mohapatra

Journal of Sustainable Mining

The land is one of the most treasures to support life, like food, fibre, medicine, and minerals, etc. Stone quarrying is one of the key elements which supports socio-economic development and industrial expansion. RS and GIS play an important role in environmental assessment to monitor the stone quarries and related activities for time to time. The present study was carried out to evaluate the impact of stone quarrying and crushing activities (SQCA) on land resources. Therefore, matrix change analysis of 2021, 2015, 2008 and 2003 were used for change detection. High-resolution Google Earth Pro images were used for the assessment …

Predictive Model Of Seismic Vibrations’ Peak Value Induced By Multi-Face Blasting, Krzysztof Fuławka, Lech Stolecki, Piotr Mertuszka, Marcin Szumny, Arkadiusz Anderko

Journal of Sustainable Mining

The seismicity level induced by blasting in the Polish copper mines is very important inlight of the efficiency of active rockburst prevention and safe conduct of blasting operations in the vicinity of the mining infrastructure such as shafts, workings, or function chambers (e.g., workshops, storages, etc.). Knowledge of the seismic vibrations’ peak value might be the basis for designing blasting works in a way that ensures desired seismic effect. However, current experiences show that Peak Particle Velocity prediction models developed so far do not apply to multi-face blasting, where there are many vibrations’ sources at the same time dotted across …

Managing The Rock Mass Destruction Under The Explosion, Maksym Kononenko, Oleh Khomenko, Ivan Sadovenko, Valeriy Sobolev, Yuliya Pazynich, Adam Smoliński

Journal of Sustainable Mining

Using the theory of elasticity and the main provisions of the quasi-static-wave hypothesis of the mechanism of the destruction of a solid medium under the action of an explosion, analytical modelling of the parameters of the formation of crumpling zones and crushing of the rock mass around the charging cavity during its explosive loading was carried out. Analytical models of the radii of the crumpling, intensive fragmentation and fracturing zones formed around the charging cavity in the rock mass during its explosive loading, taking into account the pressure of the explosion products, the limit of tensile-compressive strength of the rocks, …

Application Geological Strength Index (Gsi) Quantification Method On The Characterization Of Carbonate Rock Mass, Singgih Saptono, Danu Mirza Rezky

Journal of Sustainable Mining

Determining GSI as a representation of the presence of rock mass in slope analysis continues to develop. The development of the quantitative GSI method was carried out because the basic (qualitative) GSI values were deemed too subjective so the results from the use of the quantitative GSIwere expected to be more objective and accurate. The method used is to combine 3 GSI quantitative methods to find GSI based on surface conditions and joint structure. The results showed that the Quantitative GSI value was smaller than the GSI predictive value (qualitative). The GSI approach with RQD and UCS parameters is also …

Nickel Recovery From Low-Grade Laterites: Study Of Thermal Pre-Treatments To Improve The Efficiency Of The Hydrometallurgical Process, Johana Borda, Robinson Torres

Journal of Sustainable Mining

The processing of lower-grade laterites to obtain nickel has increased due to the gradual depletion of higher-grade sulphide ore reserves. However, the extraction from laterites has been limited because conventional technologies imply a considerable expense of energy or reagents. In this document, the effect of thermal pre-treatments on a laterite sample is demonstrated to improve nickel leaching under moderate conditions. The influence of agents such as coke, coal and NaCl in the heat treatment was also studied. With the results it is presumed that part of the nickel occluded in the goethite migrates to the iron oxides surface during the …

European Feedback On Post-Mining Seismicity, Isabelle Contrucci, Dalija Namjesnik, Peter Niemz, Paloma Primo, Andrzej Kotyrba, Grzegorz Mutke, Petr Konicek, Pascal Dominique, Tobias Rudolph, Stefan Möllerherm, Jannes Kinscher, Emmanuelle Klein, Simone Cesca

Journal of Sustainable Mining

Following the Paris Agreement adopted in 2015, Europe has committed to reducing its greenhouse gas emissions. In this context, the abandonment of coal as an energy source, both in terms of consumption and production, will lead to the closure of many mines in the years to come.

Mine closure guidelines to manage residual mining risks already exist in European countries. However, they do not include post-mining seismic risk management due to a lack of sufficient studies and knowledge on this subject. After mining closure, the flooding of the mining works leads to hydromechanical loading of the underground and, in the …

Change Detection Of Open-Pit Mines Based On Fm-Unet++ And Gf-2 Satellite Images, Du Shouhang, Li Wei, Xing Jianghe, Zhang Chengye, She Changchao, Wang Shaoyu, Li Jun

Coal Geology & Exploration

Automatic extraction of land use change information in open-pit mines using the remote sensing and deep learning technology is of great significance for the mining monitoring and ecological environmental protection. A novel deep learning model FM-UNet++ was constructed for the change of land use types in complex and heterogeneous mining scenarios, and the automatic change detection of open-pit mines was achieved using the Gaofen-2 (GF-2) satellite images. Firstly, the change detection dataset of open-pit mine was produced through data surveys and visual interpretation, which was augmented by data enhancement. Secondly, the FM-UNet++ for open-pit mine change detection was constructed by …

Underground Coal Gasification Field Tests In China: History And Prospects, Qin Yong, Yi Tongsheng, Yang Lei, Zhou Yongfeng, Wang Jun, Wang Lingxia

Coal Geology & Exploration

To achieve peak carbon dioxide emissions and carbon neutrality in China, a low-carbon and efficient coal energy structure is essential for the sustainable energy development of China. Underground coal gasification (UCG) is an important strategy for transforming the coal energy structure in China. Based on the review of previous literature, this study analyzes the exploration history of the UCG field tests in China and delivers the prospects of UCG industrialization in China. The analytical results show that the development and field tests of UCG technologies in China have experienced five stages, namely the initial attempt, silence/recovery, extensive explorations, making technological …

Construction And Engineering Applications Of Block Model For Coal Seam Value Considering The Variations In Coal Seam Thickness And Quality, Liu Feiyue, Yang Ke, Yang Tianhong, Kan Lei, Fu Kai

Coal Geology & Exploration

The variations in coal seam thickness and coal quality parameters (i.e., calorific value, volatile matter, ash content, and sulfur content) determine the spatial distribution of coal prices. The accurate characterization of coal seams’ economic value plays an important role in the rational mining and utilization of coal resources. This study first determined that the geological attributes of coal seams including their thickness and coal quality are regional variables. Based on this, this study discretized geological bodies in the study area using a block model. Then, using a geostatistical method, this study obtained the experimental semivariograms of coal seam thickness and …

Applicability Evaluation Technology Of Perforating Parameters In Different Reservoirs, Bi Gang, Wu Jiemin, Yang Shangyu, Li Mengmeng, Han Fei, Wang Xin, Cui Ying

Coal Geology & Exploration

Perforating parameters have an important impact on the productivity of oil and gas wells. Currently, the optimization of perforating parameters is mostly based on single factor analysis, with no multi-factor comprehensive evaluation analysis performed. In this paper, the finite element simulation method was used to analyze and study the influence law of perforating parameters on wellhead flow under different reservoir conditions. Firstly, a geometric model of pressure drop in reservoir with perforation completion was established to simulate the fluid flow after perforation. In this way, the influence laws of perforating parameters, anisotropy parameters and natural fracture parameters on the pressure …

Construction And Restoration Technology Of Terrain Remodeling Layer In The Restoration Of Ecological Geological Layer In Open-Pit Mining Areas, Zhao Xin, Wang Tong, Li Congcong, Lin Zhongyue, Li Fei, Wang Weichao, Feng Kangning, Yin Yalei, Jiang Zhe

Coal Geology & Exploration

Mining can easily result in a series of change in the geomorphic form, such as irregular mining pits, high and steep slopes, slag hills, primitive soil failure and accumulated water in mining pits in the plateau and alpine mining area, which is in disharmony with the surrounding environment. Such changes of geomorphic form will not only adversely affect the surface ecological environment, but also bring different degrees of influence and damage to the shallow groundwater seepage field and the permafrost. In particular, the geological hazards and disasters such as landslides and collapses may even be resulted in. In response to …

Uav Aerial Triangulation: Point Error Distributions And The Influencing Mechanisms Of Ground Control Points On Its Accuracy, Zha Jianfeng, Zhu Pengcheng, Wu Dejun, Ma Chenyang, Zhong Chongwu, Yin Hongwu, Wang Dong

Coal Geology & Exploration

Unmanned aerial vehicles (UAVs) have been an important means of monitoring the surface deformation in mining areas since they are flexible, are insensitive to weather, and can swiftly acquire images of target areas. However, there is an urgent need to improve UAV-based measurement accuracy. Based on a systematic analysis of factors affecting the accuracy of surface measurement points, this study focuses on the influence of the quality of ground control points on the point error distribution and accuracy of aerial triangulation. Firstly, through a large number of repeated observations and experiments, this study investigated the error distributions of the planar …

Research Advances On The Techno-Economic Evaluation Of Ucg Projects, Yi Tongsheng, Qin Yong, Zhou Yongfeng, Wang Lingxia, Jin Jun, Zhou Ze

Coal Geology & Exploration

Underground coal gasification (UCG) is driven by China's development strategy for a clean and efficient coal energy structure. Its industrialization prospect depends on the economic and social benefits of UCG projects. Against this background, this study reviews the research advances on the economic evaluation of UCG projects at home and abroad and summarizes the current insights into the economic competitiveness of UCG projects. Through case analysis, it presents a basic model for the economic evaluation of the UCG-combined-cycle gas turbine (CCGT) - carbon capture and storage (UCG-CCGT-CCS) system and the main understanding of the model. Furthermore, this study discusses the …

Ucg Industrialization In The Soviet Union: History And Comments, Kong Weimin, Zhou Yongfeng, Yi Tongsheng, Li Ping, Qin Yong, Zhou Ze

Coal Geology & Exploration

China's energy resources are originally poor in oil and gas but rich in coal. The industrialization of underground coal gasification (UCG) technologies, which is an important way of achieving a low-carbon and efficient coal energy structure in China, contributes to the smooth achievement of the peak carbon dioxide emissions and carbon neutrality in China. This study reviews the history of the field tests and industrialization of UCG technologies in the Soviet Union by systematically referencing and sorting literature, aiming to provide a reference for the present development and industrialization of UCG technologies in China. The results show that the development …

Ucg Pilot Tests In The United States And Their Contributions To Modern Ucg Technologies, Huang Wan, Wang Jun, Wang Lingxia, Yi Tongsheng, Chen Kexin, Qin Yong

Coal Geology & Exploration

The industrialization of underground coal gasification (UCG), which is conducive to the transformation and development of the coal energy structure and the improvement in the low-carbon utilization level of coal resources, is an environmentally friendly energy development technology in line with the sustainable development strategy. The international energy crisis from the 1980s to the 1990s prompted the United States to vigorously develop UCG technologies. Accordingly, this country has successively carried out six series of UCG pilot tests, which contribute greatly to the progress in UCG technologies and provided the critical foundation for the formation of modern UCG technologies worldwide. This …

Ucg Pilot Tests In Eu Countries: A Review Of History And Progress, Jin Lili, Yang Lei, Wu Yarong, Wang Xiaofang, Yi Tongsheng, Qin Yong

Coal Geology & Exploration

Underground coal gasification (UCG) is an important way of transforming China’s coal energy structure. European Union (EU) countries explored UCG for over 80 years, and their rich experience can be used as a reference for promoting UCG industrialization in China. The UK prepared for UCG pilot tests for the first time in the world. From 1944 to 2014, based on the experience of the former Soviet Union and the United States, EU countries successively implemented at least 12 UCG pilot test projects in three stages, making important contributions to the progress in UCG technologies. They invented the blind-hole method and …

Ucg Engineering Demonstrations In Australia: History And Its Implications, Zhou Ze, Wang Lingxia, Qin Yong, Jin Jun, Yang Lei, Yi Tongsheng

Coal Geology & Exploration

Underground coal gasification (UCG), which is a revolutionary coal mining technology, is an important direction for achieving a low-carbon and efficient coal energy structure in China and is also a potential explorable way to ensure the smooth realization of the peak carbon dioxide emissions and carbon neutrality in China. Based on a literature survey, this study sorts out the exploration process of UCG technologies in Australia and analyzes the gains and losses using field test cases. The experience in UCG technologies in Australia can provide a reference for the development of the technologies in China. The results show that the …