Pub Date : 2024-09-01DOI: 10.1016/j.ijmst.2024.08.001
Eloy Peña-Asensio , Josep M. Trigo-Rodríguez , Jordi Sort , Jordi Ibáñez-Insa , Albert Rimola
Amid the scarcity of lunar meteorites and the imperative to preserve their scientific value, non-destructive testing methods are essential. This translates into the application of microscale rock mechanics experiments and scanning electron microscopy for surface composition analysis. This study explores the application of Machine Learning algorithms in predicting the mineralogical and mechanical properties of DHOFAR 1084, JAH 838, and NWA 11444 lunar meteorites based solely on their atomic percentage compositions. Leveraging a prior-data fitted network model, we achieved near-perfect classification scores for meteorites, mineral groups, and individual minerals. The regressor models, notably the K-Neighbor model, provided an outstanding estimate of the mechanical properties—previously measured by nanoindentation tests—such as hardness, reduced Young’s modulus, and elastic recovery. Further considerations on the nature and physical properties of the minerals forming these meteorites, including porosity, crystal orientation, or shock degree, are essential for refining predictions. Our findings underscore the potential of Machine Learning in enhancing mineral identification and mechanical property estimation in lunar exploration, which pave the way for new advancements and quick assessments in extraterrestrial mineral mining, processing, and research.
{"title":"Machine learning applications on lunar meteorite minerals: From classification to mechanical properties prediction","authors":"Eloy Peña-Asensio , Josep M. Trigo-Rodríguez , Jordi Sort , Jordi Ibáñez-Insa , Albert Rimola","doi":"10.1016/j.ijmst.2024.08.001","DOIUrl":"10.1016/j.ijmst.2024.08.001","url":null,"abstract":"<div><div>Amid the scarcity of lunar meteorites and the imperative to preserve their scientific value, non-destructive testing methods are essential. This translates into the application of microscale rock mechanics experiments and scanning electron microscopy for surface composition analysis. This study explores the application of Machine Learning algorithms in predicting the mineralogical and mechanical properties of DHOFAR 1084, JAH 838, and NWA 11444 lunar meteorites based solely on their atomic percentage compositions. Leveraging a prior-data fitted network model, we achieved near-perfect classification scores for meteorites, mineral groups, and individual minerals. The regressor models, notably the <em>K</em>-Neighbor model, provided an outstanding estimate of the mechanical properties—previously measured by nanoindentation tests—such as hardness, reduced Young’s modulus, and elastic recovery. Further considerations on the nature and physical properties of the minerals forming these meteorites, including porosity, crystal orientation, or shock degree, are essential for refining predictions. Our findings underscore the potential of Machine Learning in enhancing mineral identification and mechanical property estimation in lunar exploration, which pave the way for new advancements and quick assessments in extraterrestrial mineral mining, processing, and research.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"34 9","pages":"Pages 1283-1292"},"PeriodicalIF":11.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.ijmst.2024.08.004
Shuohui Yin , Yingjie Wang , Jingang Liu
The exploration of Mars would heavily rely on Martian rocks mechanics and engineering technology. As the mechanical property of Martian rocks is uncertain, it is of utmost importance to predict the probability distribution of Martian rocks mechanical property for the success of Mars exploration. In this paper, a fast and accurate probability distribution method for predicting the macroscale elastic modulus of Martian rocks was proposed by integrating the microscale rock mechanical experiments (micro-RME), accurate grain-based modeling (AGBM) and upscaling methods based on reliability principles. Firstly, the microstructure of NWA12564 Martian sample and elastic modulus of each mineral were obtained by micro-RME with TESCAN integrated mineral analyzer (TIMA) and nanoindentation. The best probability distribution function of the minerals was determined by Kolmogorov-Smirnov (K-S) test. Secondly, based on best distribution function of each mineral, the Monte Carlo simulations (MCS) and upscaling methods were implemented to obtain the probability distribution of upscaled elastic modulus. Thirdly, the correlation between the upscaled elastic modulus and macroscale elastic modulus obtained by AGBM was established. The accurate probability distribution of the macroscale elastic modulus was obtained by this correlation relationship. The proposed method can predict the probability distribution of Martian rocks mechanical property with any size and shape samples.
{"title":"Predicting the probability distribution of Martian rocks mechanical property based on microscale rock mechanical experiments and accurate grain-based modeling","authors":"Shuohui Yin , Yingjie Wang , Jingang Liu","doi":"10.1016/j.ijmst.2024.08.004","DOIUrl":"10.1016/j.ijmst.2024.08.004","url":null,"abstract":"<div><div>The exploration of Mars would heavily rely on Martian rocks mechanics and engineering technology. As the mechanical property of Martian rocks is uncertain, it is of utmost importance to predict the probability distribution of Martian rocks mechanical property for the success of Mars exploration. In this paper, a fast and accurate probability distribution method for predicting the macroscale elastic modulus of Martian rocks was proposed by integrating the microscale rock mechanical experiments (micro-RME), accurate grain-based modeling (AGBM) and upscaling methods based on reliability principles. Firstly, the microstructure of NWA12564 Martian sample and elastic modulus of each mineral were obtained by micro-RME with TESCAN integrated mineral analyzer (TIMA) and nanoindentation. The best probability distribution function of the minerals was determined by Kolmogorov-Smirnov (K-S) test. Secondly, based on best distribution function of each mineral, the Monte Carlo simulations (MCS) and upscaling methods were implemented to obtain the probability distribution of upscaled elastic modulus. Thirdly, the correlation between the upscaled elastic modulus and macroscale elastic modulus obtained by AGBM was established. The accurate probability distribution of the macroscale elastic modulus was obtained by this correlation relationship. The proposed method can predict the probability distribution of Martian rocks mechanical property with any size and shape samples.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"34 9","pages":"Pages 1327-1339"},"PeriodicalIF":11.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655793","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.ijmst.2024.04.012
Shutian Cao , Fengshou Zhang , Mengke An , Derek Elsworth , Manchao He , Hai Liu , Luanxiao Zhao
Basalt is a major component of the earth and moon crust. Mineral composition and temperature influence frictional instability and thus the potential for seismicity on basaltic faults. We performed velocity-stepping shear experiments on basalt gouges at a confining pressure of 100 MPa, temperatures in the range of 100–400 °C and with varied obsidian mass fractions of 0–100% under wet/dry conditions to investigate the frictional strength and stability of basaltic faults. We observe a transition from velocity-neutral to velocity-weakening behaviors with increasing obsidian content. The frictional stability response of the mixed obsidian/basalt gouges is characterized by a transition from velocity-strengthening to velocity-weakening at 200 °C and another transition to velocity-strengthening at temperatures >300 °C. Conversely, frictional strengths of the obsidian-bearing gouges are insensitive to temperature and wet/dry conditions. These results suggest that obsidian content dominates the potential seismic response of basaltic faults with the effect of temperature controlling the range of seismogenic depths. Thus, shallow moonquakes tend to occur in the lower lunar crust due to the corresponding anticipated higher glass content and a projected temperature range conducive to velocity-weakening behavior. These observations contribute to a better understanding of the nucleation mechanism of shallow seismicity in basaltic faults.
{"title":"Gouge stability controlled by temperature elevation and obsidian addition in basaltic faults and implications for moonquakes","authors":"Shutian Cao , Fengshou Zhang , Mengke An , Derek Elsworth , Manchao He , Hai Liu , Luanxiao Zhao","doi":"10.1016/j.ijmst.2024.04.012","DOIUrl":"10.1016/j.ijmst.2024.04.012","url":null,"abstract":"<div><div>Basalt is a major component of the earth and moon crust. Mineral composition and temperature influence frictional instability and thus the potential for seismicity on basaltic faults. We performed velocity-stepping shear experiments on basalt gouges at a confining pressure of 100 MPa, temperatures in the range of 100–400 °C and with varied obsidian mass fractions of 0–100% under wet/dry conditions to investigate the frictional strength and stability of basaltic faults. We observe a transition from velocity-neutral to velocity-weakening behaviors with increasing obsidian content. The frictional stability response of the mixed obsidian/basalt gouges is characterized by a transition from velocity-strengthening to velocity-weakening at 200 °C and another transition to velocity-strengthening at temperatures >300 °C. Conversely, frictional strengths of the obsidian-bearing gouges are insensitive to temperature and wet/dry conditions. These results suggest that obsidian content dominates the potential seismic response of basaltic faults with the effect of temperature controlling the range of seismogenic depths. Thus, shallow moonquakes tend to occur in the lower lunar crust due to the corresponding anticipated higher glass content and a projected temperature range conducive to velocity-weakening behavior. These observations contribute to a better understanding of the nucleation mechanism of shallow seismicity in basaltic faults.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"34 9","pages":"Pages 1273-1282"},"PeriodicalIF":11.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141404070","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1016/j.ijmst.2024.09.001
Haichun Hao, Mingzhong Gao, Yan Wu, Zheng Gao, Yongcheng Li, Xuemin Zhou, Peng Chu, Xuan Wang, Jiahua Li, Lang Zhou, Jie Song, Tianxiang Ao, Yikun Yang
The lunar surface and its deep layers contain abundant resources and valuable information resources, the exploration and exploitation of which are important for the sustainable development of the human economy and society. Technological exploration and research in the field of deep space science, especially lunar-based exploration, is a scientific strategy that has been pursued in China and worldwide. Drilling and sampling are key to accurate exploration of the desirable characteristics of deep lunar resources. In this study, an in-situ condition preserved coring (ICP-Coring) and analysis system, which can be used to test drilling tools and develop effective sampling strategies, was designed. The key features of the system include: (1) capability to replicate the extreme temperature fluctuations of the lunar environment (−185 to 200 °C) with intelligent temperature control; (2) ability to maintain a vacuum environment at a scale of 10−3 Pa, both under unloaded conditions within a ϕ580 mm × 1000 mm test chamber, and under loaded conditions using a ϕ400 mm × 800 mm lunar rock simulant; (3) application of axial pressures up to 4 MPa and confining pressures up to 3.5 MPa; (4) sample rotation at any angle with a maximum sampling length of 800 mm; and (5) multiple modes of rotary-percussive drilling, controlled by penetration speed and weight on bit (WOB). Experimental studies on the drilling characteristics in the lunar rock simulant-loaded state under different drill bit-percussive-vacuum environment configurations were conducted. The results show that the outgassing rate of the lunar soil simulant is greater than that of the lunar rock simulant and that a low-temperature environment contributes to a reduced vacuum of the lunar-based simulated environment. The rotary-percussive drilling method effectively shortens the sampling time. With increasing sampling depth, the temperature rise of the drilling tools tends to rapidly increase, followed by slow growth or steady fluctuations. The temperature rise energy accumulation of the drill bits under vacuum is more significant than that under atmospheric pressure, approximately 1.47 times higher. The real-time monitored drilling pressure, penetration speed and rotary torque during drilling serve as parameters for discriminating the drilling status. The results of this research can provide a scientific basis for returning samples from lunar rock in extreme lunar-based environments.
月球表面及其深层蕴藏着丰富的资源和宝贵的信息资源，对这些资源的探索和利用对人类经济社会的可持续发展具有重要意义。在深空科学领域进行技术探索和研究，特别是月球探测，是中国和世界一直奉行的科学战略。钻探和取样是准确探测月球深部资源理想特性的关键。本研究设计了一套原位条件保存取芯（ICP-Coring）和分析系统，可用于测试钻探工具和制定有效的取样策略。该系统的主要特点包括(1) 能够通过智能温度控制复制月球环境的极端温度波动（-185 至 200 °C）；(2) 能够维持 10-3 Pa 的真空环境，包括在 ϕ580 mm × 1000 mm 试验室内的无负荷条件下，以及在使用 ϕ400 mm × 800 mm 月球岩石模拟物的负荷条件下；(3) 施加高达 4 MPa 的轴向压力和高达 3.5 兆帕；(4) 以任意角度旋转取样，最大取样长度为 800 毫米；(5) 多种旋转-冲击钻进模式，由穿透速度和钻头重量 (WOB) 控制。对不同钻头-冲击-真空环境配置下月球岩石模拟加载状态的钻探特性进行了实验研究。结果表明，月球土壤模拟物的放气率大于月球岩石模拟物，低温环境导致月球模拟环境的真空度降低。旋转冲击式钻探方法有效地缩短了取样时间。随着取样深度的增加，钻具的温升呈快速上升趋势，随后缓慢上升或平稳波动。真空条件下钻头的温升能量积累比常压条件下更为显著，约为常压条件下的 1.47 倍。钻进过程中实时监测到的钻压、钻进速度和旋转扭矩可作为判别钻进状态的参数。该研究成果可为在极端月基环境中返回月岩样本提供科学依据。
{"title":"Design, test, and verification of in-situ condition preserved coring and analysis system in lunar-based simulation environment","authors":"Haichun Hao, Mingzhong Gao, Yan Wu, Zheng Gao, Yongcheng Li, Xuemin Zhou, Peng Chu, Xuan Wang, Jiahua Li, Lang Zhou, Jie Song, Tianxiang Ao, Yikun Yang","doi":"10.1016/j.ijmst.2024.09.001","DOIUrl":"10.1016/j.ijmst.2024.09.001","url":null,"abstract":"<div><div>The lunar surface and its deep layers contain abundant resources and valuable information resources, the exploration and exploitation of which are important for the sustainable development of the human economy and society. Technological exploration and research in the field of deep space science, especially lunar-based exploration, is a scientific strategy that has been pursued in China and worldwide. Drilling and sampling are key to accurate exploration of the desirable characteristics of deep lunar resources. In this study, an in-situ condition preserved coring (ICP-Coring) and analysis system, which can be used to test drilling tools and develop effective sampling strategies, was designed. The key features of the system include: (1) capability to replicate the extreme temperature fluctuations of the lunar environment (−185 to 200 °C) with intelligent temperature control; (2) ability to maintain a vacuum environment at a scale of 10<sup>−3</sup> Pa, both under unloaded conditions within a <em>ϕ</em>580 mm × 1000 mm test chamber, and under loaded conditions using a <em>ϕ</em>400 mm × 800 mm lunar rock simulant; (3) application of axial pressures up to 4 MPa and confining pressures up to 3.5 MPa; (4) sample rotation at any angle with a maximum sampling length of 800 mm; and (5) multiple modes of rotary-percussive drilling, controlled by penetration speed and weight on bit (WOB). Experimental studies on the drilling characteristics in the lunar rock simulant-loaded state under different drill bit-percussive-vacuum environment configurations were conducted. The results show that the outgassing rate of the lunar soil simulant is greater than that of the lunar rock simulant and that a low-temperature environment contributes to a reduced vacuum of the lunar-based simulated environment. The rotary-percussive drilling method effectively shortens the sampling time. With increasing sampling depth, the temperature rise of the drilling tools tends to rapidly increase, followed by slow growth or steady fluctuations. The temperature rise energy accumulation of the drill bits under vacuum is more significant than that under atmospheric pressure, approximately 1.47 times higher. The real-time monitored drilling pressure, penetration speed and rotary torque during drilling serve as parameters for discriminating the drilling status. The results of this research can provide a scientific basis for returning samples from lunar rock in extreme lunar-based environments.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"34 9","pages":"Pages 1259-1272"},"PeriodicalIF":11.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Knowledge of the mechanical behavior of planetary rocks is indispensable for space explorations. The scarcity of pristine samples and the irregular shapes of planetary meteorites make it difficult to obtain representative samples for conventional macroscale rock mechanics experiments (macro-RMEs). This critical review discusses recent advances in microscale RMEs (micro-RMEs) techniques and the upscaling methods for extracting mechanical parameters. Methods of mineralogical and microstructural analyses, along with non-destructive mechanical techniques, have provided new opportunities for studying planetary rocks with unprecedented precision and capabilities. First, we summarize several mainstream methods for obtaining the mineralogy and microstructure of planetary rocks. Then, nondestructive micromechanical testing methods, nanoindentation and atomic force microscopy (AFM), are detailed reviewed, illustrating the principles, advantages, influencing factors, and available testing results from literature. Subsequently, several feasible upscaling methods that bridge the micro-measurements of meteorite pieces to the strength of the intact body are introduced. Finally, the potential applications of planetary rock mechanics research to guiding the design and execution of space missions are environed, ranging from sample return missions and planetary defense to extraterrestrial construction. These discussions are expected to broaden the understanding of the microscale mechanical properties of planetary rocks and their significant role in deep space exploration.
{"title":"Micromechanical testing and property upscaling of planetary rocks: A critical review","authors":"Yiwei Liu , Guoping Zhang , Jiangmei Qiao , Xuhai Tang","doi":"10.1016/j.ijmst.2024.08.002","DOIUrl":"10.1016/j.ijmst.2024.08.002","url":null,"abstract":"<div><div>Knowledge of the mechanical behavior of planetary rocks is indispensable for space explorations. The scarcity of pristine samples and the irregular shapes of planetary meteorites make it difficult to obtain representative samples for conventional macroscale rock mechanics experiments (macro-RMEs). This critical review discusses recent advances in microscale RMEs (micro-RMEs) techniques and the upscaling methods for extracting mechanical parameters. Methods of mineralogical and microstructural analyses, along with non-destructive mechanical techniques, have provided new opportunities for studying planetary rocks with unprecedented precision and capabilities. First, we summarize several mainstream methods for obtaining the mineralogy and microstructure of planetary rocks. Then, nondestructive micromechanical testing methods, nanoindentation and atomic force microscopy (AFM), are detailed reviewed, illustrating the principles, advantages, influencing factors, and available testing results from literature. Subsequently, several feasible upscaling methods that bridge the micro-measurements of meteorite pieces to the strength of the intact body are introduced. Finally, the potential applications of planetary rock mechanics research to guiding the design and execution of space missions are environed, ranging from sample return missions and planetary defense to extraterrestrial construction. These discussions are expected to broaden the understanding of the microscale mechanical properties of planetary rocks and their significant role in deep space exploration.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"34 9","pages":"Pages 1217-1241"},"PeriodicalIF":11.7,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1016/j.ijmst.2024.08.009
Mengyao Qi , Weijun Peng , Wei Wang , Yijun Cao , Longyu Zhang , Yukun Huang
A novel small molecule depressant (M-DEP) was used to separate chalcopyrite and molybdenite via flotation. The results showed that M-DEP had an excellent selective depression on molybdenite, while had little effect on the flotation of chalcopyrite. The adsorption capacity of M-DEP on the surface of molybdenite was greater than that on chalcopyrite surface. The adsorption of M-DEP reduced the floatability of molybdenite and had less effect on the floatability of chalcopyrite, which was due to its different adsorption modes on the surface of the two minerals. Furthermore, the interaction between chalcopyrite and M-DEP was mainly chemical interaction, and almost all of the adsorbed M-DEP molecules were removed and replaced by sodium butyl xanthate (SBX). By contrast, hydrophobic interaction was the main way in which M-DEP was adsorbed on the molybdenite surface with little chemical interaction, which was less interfered by SBX addition. Therefore, M-DEP had a super selective depression on molybdenite. The study provided a novel depressant and approach for the deep separation of chalcopyrite and molybdenite via flotation.
{"title":"A novel molybdenite depressant for efficient selective flotation separation of chalcopyrite and molybdenite","authors":"Mengyao Qi , Weijun Peng , Wei Wang , Yijun Cao , Longyu Zhang , Yukun Huang","doi":"10.1016/j.ijmst.2024.08.009","DOIUrl":"10.1016/j.ijmst.2024.08.009","url":null,"abstract":"<div><div>A novel small molecule depressant (M-DEP) was used to separate chalcopyrite and molybdenite via flotation. The results showed that M-DEP had an excellent selective depression on molybdenite, while had little effect on the flotation of chalcopyrite. The adsorption capacity of M-DEP on the surface of molybdenite was greater than that on chalcopyrite surface. The adsorption of M-DEP reduced the floatability of molybdenite and had less effect on the floatability of chalcopyrite, which was due to its different adsorption modes on the surface of the two minerals. Furthermore, the interaction between chalcopyrite and M-DEP was mainly chemical interaction, and almost all of the adsorbed M-DEP molecules were removed and replaced by sodium butyl xanthate (SBX). By contrast, hydrophobic interaction was the main way in which M-DEP was adsorbed on the molybdenite surface with little chemical interaction, which was less interfered by SBX addition. Therefore, M-DEP had a super selective depression on molybdenite. The study provided a novel depressant and approach for the deep separation of chalcopyrite and molybdenite via flotation.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"34 8","pages":"Pages 1179-1196"},"PeriodicalIF":11.7,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1016/j.ijmst.2024.08.008
Jiaxin Zhuang , Zonglong Mu , Wu Cai , Hu He , Lee J. Hosking , Guojun Xi , Biao Jiao
Multistage hydraulic fracturing of horizontal wells (MFHW) is a promising technology for controlling coal burst caused by thick and hard roofs in China. However, challenges remain regarding the MFHW control mechanism of coal burst and assessment of the associated fracturing effects. In this study, these challenges were investigated through numerical modelling and field applications, based on the actual operating parameters of MFHW for hard roofs in a Chinese coal mine. A damage parameter (D) is proposed to assess the degree of hydraulic fracturing in the roof. The mechanisms and effects of MFHW for controlling coal burst are analyzed using microseismic (MS) data and front-abutment stress distribution. Results show that the degree of fracturing can be categorized into lightly-fractured (D≤0.3), moderately fractured (0.3<D≤0.6), well-fractured (0.6<D≤0.9), and over-fractured (0.9<D≤0.95). A response stage in the fracturing process, characterized by a slowdown in crack development, indicates the transition to a well-fractured condition. After MFHW, the zone range and peak value of the front-abutment stress decrease. Additionally, MS events shift from near the coal seam to the fractured roof layers, with the number of MS events increases while the average MS energy decreases. The MFHW control mechanisms of coal bursts involve mitigating mining-induced stress and reducing seismic activity during longwall retreat, ensuring stresses remain below the ultimate stress level. These findings provide a reference for evaluating MFHW fracturing effects and controlling coal burst disasters in engineering.
{"title":"Multistage hydraulic fracturing of a horizontal well for hard roof related coal burst control: Insights from numerical modelling to field application","authors":"Jiaxin Zhuang , Zonglong Mu , Wu Cai , Hu He , Lee J. Hosking , Guojun Xi , Biao Jiao","doi":"10.1016/j.ijmst.2024.08.008","DOIUrl":"10.1016/j.ijmst.2024.08.008","url":null,"abstract":"<div><div>Multistage hydraulic fracturing of horizontal wells (MFHW) is a promising technology for controlling coal burst caused by thick and hard roofs in China. However, challenges remain regarding the MFHW control mechanism of coal burst and assessment of the associated fracturing effects. In this study, these challenges were investigated through numerical modelling and field applications, based on the actual operating parameters of MFHW for hard roofs in a Chinese coal mine. A damage parameter (<em>D</em>) is proposed to assess the degree of hydraulic fracturing in the roof. The mechanisms and effects of MFHW for controlling coal burst are analyzed using microseismic (MS) data and front-abutment stress distribution. Results show that the degree of fracturing can be categorized into lightly-fractured (<em>D</em>≤0.3), moderately fractured (0.3<<em>D</em>≤0.6), well-fractured (0.6<<em>D</em>≤0.9), and over-fractured (0.9<<em>D</em>≤0.95). A response stage in the fracturing process, characterized by a slowdown in crack development, indicates the transition to a well-fractured condition. After MFHW, the zone range and peak value of the front-abutment stress decrease. Additionally, MS events shift from near the coal seam to the fractured roof layers, with the number of MS events increases while the average MS energy decreases. The MFHW control mechanisms of coal bursts involve mitigating mining-induced stress and reducing seismic activity during longwall retreat, ensuring stresses remain below the ultimate stress level. These findings provide a reference for evaluating MFHW fracturing effects and controlling coal burst disasters in engineering.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"34 8","pages":"Pages 1095-1114"},"PeriodicalIF":11.7,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01DOI: 10.1016/j.ijmst.2024.07.010
Tingsheng Qiu , Kaiwei Ding , Huashan Yan , Liu Yang , Hao Wu , Guanfei Zhao , Xianhui Qiu
The electrochemical interaction between galena and monoclinic pyrrhotite was investigated to examine its impact on the physical and chemical properties of the mineral micro-surface. This investigation employed techniques such as electrochemistry, metal ion stripping, X-ray photoelectron spectroscopy, and quantum chemistry. The electrochemical test results demonstrate that the galena surface in the electro-couple system exhibits a lower electrostatic potential and higher electrochemical activity compared to the monoclinic pyrrhotite surface, rendering it more susceptible to oxidation dissolution. Monoclinic pyrrhotite significantly amplifies the corrosion rate of the galena surface. Mulliken charge population calculations indicate that electrons are consistently transferred from galena to monoclinic pyrrhotite, with the number of electron transfers on the mineral surface increasing as the interaction distance decreases. The analysis of state density revealed a shift in the surface state density of galena towards lower energy levels, resulting in decreased reactivity and increased difficulty for the reagent to adsorb onto the mineral surface. Conversely, monoclinic pyrrhotite exhibited an opposite trend. The X-ray photoelectron spectroscopy (XPS) test results indicate that galvanic interaction leads to the formation of hydrophilic substances, PbSxOy and Pb(OH)2, on the surface of galena. Additionally, the surface of monoclinic pyrrhotite not only adsorbs Pb2+ but also undergoes S0 formation, thereby augmenting its hydrophobic nature.
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