International Journal of Mining Science and Technology最新文献

Multi-frequency formation mechanism and modulation strategy of self-priming enhanced submerged pulsed waterjet

IF 11.7 1区工程技术 Q1 MINING & MINERAL PROCESSING

International Journal of Mining Science and Technology

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmst.2025.01.002

Haojie Jia , Yanwei Liu , Weiqin Zuo , Hongkai Han , Ping Chang , Mohammad Waqar Ali Asad , Guozhong Hu , Jian Miao , Hani S. Mitri

Under submerged conditions, compared with traditional self-excited oscillating pulsed waterjets (SOPWs), annular fluid-enhanced self-excited oscillating pulsed waterjets (AFESOPWs) exhibit a higher surge pressure through self-priming. However, their pressure frequency and cavitation characteristics remain unclear, resulting in an inability to fully utilize resonance and cavitation erosion to break coal and rock. In this study, high-frequency pressure testing, high-speed photography, and large eddy simulation (LES) are used to investigate the distribution of the pressure frequency band, evolution law of the cavitation cloud, and its regulation mechanism of a continuous waterjet, SOPW, and AFESOPW. The results indicated that the excitation of the plunger pump, shearing layer vortex, and bubble collapse corresponded to the three high-amplitude frequency bands of the waterjet pressure. AFESOPWs have an additional self-priming frequency that can produce a larger amplitude under a synergistic effect with the second high-amplitude frequency band. A better cavitation effect was produced after self-priming the annulus fluid, and the shedding frequency of the cavitation clouds of the three types of waterjets was linearly related to the cavitation number. The peak pressure of the waterjet and cavitation erosion effect can be improved by modulating the waterjet pressure oscillation frequency and cavitation shedding frequency.

{"title":"Multi-frequency formation mechanism and modulation strategy of self-priming enhanced submerged pulsed waterjet","authors":"Haojie Jia , Yanwei Liu , Weiqin Zuo , Hongkai Han , Ping Chang , Mohammad Waqar Ali Asad , Guozhong Hu , Jian Miao , Hani S. Mitri","doi":"10.1016/j.ijmst.2025.01.002","DOIUrl":"10.1016/j.ijmst.2025.01.002","url":null,"abstract":"<div><div>Under submerged conditions, compared with traditional self-excited oscillating pulsed waterjets (SOPWs), annular fluid-enhanced self-excited oscillating pulsed waterjets (AFESOPWs) exhibit a higher surge pressure through self-priming. However, their pressure frequency and cavitation characteristics remain unclear, resulting in an inability to fully utilize resonance and cavitation erosion to break coal and rock. In this study, high-frequency pressure testing, high-speed photography, and large eddy simulation (LES) are used to investigate the distribution of the pressure frequency band, evolution law of the cavitation cloud, and its regulation mechanism of a continuous waterjet, SOPW, and AFESOPW. The results indicated that the excitation of the plunger pump, shearing layer vortex, and bubble collapse corresponded to the three high-amplitude frequency bands of the waterjet pressure. AFESOPWs have an additional self-priming frequency that can produce a larger amplitude under a synergistic effect with the second high-amplitude frequency band. A better cavitation effect was produced after self-priming the annulus fluid, and the shedding frequency of the cavitation clouds of the three types of waterjets was linearly related to the cavitation number. The peak pressure of the waterjet and cavitation erosion effect can be improved by modulating the waterjet pressure oscillation frequency and cavitation shedding frequency.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"35 2","pages":"Pages 175-189"},"PeriodicalIF":11.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143385308","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}

引用次数: 0

Upgrading of 6–0 mm low rank high sulfur lignite by a compound dry cascade separation bed

IF 11.7 1区工程技术 Q1 MINING & MINERAL PROCESSING

International Journal of Mining Science and Technology

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmst.2025.01.007

Xiaodong Yu , Deqing Gan

In this paper, the effect of vibration intensity on the spatial distribution of sulfur content in bed particles was studied. The effects of vibration and airflow on the mechanical characteristics of particles were studied, the collision behavior mode of particles was determined, the spatial saltation law of particles was investigated, the spatial functional axis of beds was determined, and the saltation separation period of particles was determined. The test results show that: When separation bed provides inlet airflow velocity (U_in) is 2.55 m/s, the airflow distribution interval of I, II and III areas were U_I=2.55–2.57 m/s, U_II=1.33–1.35 m/s, U_III=0.35–0.38 m/s, respectively; when separation bed vibration amplitude (A) A=2.4–2.5 mm, separation bed vibration frequency (f) f=23–24 Hz, the desulfurization effect is the best. When vibration intensity (Γ) Γ=1.22, U_in=1.05 m/s, the particles have disordered contact and collision behavior. When Γ=14.89, U_in=3.18 m/s, the particles have a transition cataclastic collision. When Γ=5.80, U_in=2.55 m/s, the particles have directional collision behavior. It is determined that the OX axis is the transverse stable diffusion axis of the material, the OY axis is the longitudinal gradient transport axis of the material, and the OZ axis is the vertical density cascade distribution axis of the material. When separation time (T) T=0–10 s was the period of disorderly diffusion and mixing of particles, T=10–20 s was the period of directional migration and stratification of particles, and T=20–30 s was the period of cascade distribution and separation of particles. Finally, separation experiments conducted under optimal operating parameters demonstrated that the clean coal yield was 72.02% with a sulfur content of 0.98%.

{"title":"Upgrading of 6–0 mm low rank high sulfur lignite by a compound dry cascade separation bed","authors":"Xiaodong Yu , Deqing Gan","doi":"10.1016/j.ijmst.2025.01.007","DOIUrl":"10.1016/j.ijmst.2025.01.007","url":null,"abstract":"<div><div>In this paper, the effect of vibration intensity on the spatial distribution of sulfur content in bed particles was studied. The effects of vibration and airflow on the mechanical characteristics of particles were studied, the collision behavior mode of particles was determined, the spatial saltation law of particles was investigated, the spatial functional axis of beds was determined, and the saltation separation period of particles was determined. The test results show that: When separation bed provides inlet airflow velocity (<em>U</em><sub>in</sub>) is 2.55 m/s, the airflow distribution interval of I, II and III areas were <em>U</em><sub>I</sub>=2.55–2.57 m/s, U<sub>II</sub>=1.33–1.35 m/s, <em>U</em><sub>III</sub>=0.35–0.38 m/s, respectively; when separation bed vibration amplitude (<em>A</em>) <em>A</em>=2.4–2.5 mm, separation bed vibration frequency (<em>f</em>) <em>f</em>=23–24 Hz, the desulfurization effect is the best. When vibration intensity (<em>Γ</em>) <em>Γ</em>=1.22, <em>U</em><sub>in</sub>=1.05 m/s, the particles have disordered contact and collision behavior. When <em>Γ</em>=14.89, <em>U</em><sub>in</sub>=3.18 m/s, the particles have a transition cataclastic collision. When <em>Γ</em>=5.80, <em>U</em><sub>in</sub>=2.55 m/s, the particles have directional collision behavior. It is determined that the <em>OX</em> axis is the transverse stable diffusion axis of the material, the <em>OY</em> axis is the longitudinal gradient transport axis of the material, and the <em>OZ</em> axis is the vertical density cascade distribution axis of the material. When separation time (<em>T</em>) <em>T</em>=0–10 s was the period of disorderly diffusion and mixing of particles, <em>T</em>=10–20 s was the period of directional migration and stratification of particles, and <em>T</em>=20–30 s was the period of cascade distribution and separation of particles. Finally, separation experiments conducted under optimal operating parameters demonstrated that the clean coal yield was 72.02% with a sulfur content of 0.98%.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"35 2","pages":"Pages 307-324"},"PeriodicalIF":11.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528908","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}

引用次数: 0

Response properties of geometries of coal penetrating fracture on seepage behavior 穿煤断裂几何形状对渗流行为的响应特性

IF 11.7 1区工程技术 Q1 MINING & MINERAL PROCESSING

International Journal of Mining Science and Technology

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmst.2025.01.003

Penghua Han , Kai Wang , Jiewen Pang , Xiaofeng Ji , Cun Zhang

The fracture surfaces of coal-rock masses formed under mining-induced stress generally exhibit complex geometries, and the fracture geometry is one of the primary factors affecting the seepage characteristics of coal-rock penetrating fracture. This paper investigates the seepage characteristics of 5 groups of coal penetrating fracture (CPF) with different joint roughness coefficients (JRCs). Based on 3D morphology scanner tests and hydraulic coupling tests, a characterization method of effective geometric parameters in fracture surfaces under various confining pressures was improved, and a relationship between effective geometric parameters and the confining pressure is established. The results indicate that the nonlinear flow behavior in a CPF primarily includes three types: non-Newtonian fluid seepage under high confining pressure and low JRC, non-Darcy seepage under low confining pressure and high JRC, and the whole process of seepage characteristics between these two conditions. Among them, non-Newtonian fluid seepage is caused by significant fracture expansion, while non-Darcy seepage can be attributed to turbulence effects. During the seepage process, the geometric parameters with different JRC fracture samples all exhibit exponential changes with the increase of confining pressure. In addition, under high confining pressure, the effective contact ratio, effective fracture aperture, and void deviation ratio with high JRC fracture samples under high confining pressure increase by 93.5%, 67.4%, and 24.9%, respectively, compared with those of low JRC fracture samples. According to the variation of geometric parameters in a CPF with external stress, a seepage model considering geometric parameters in a CPF is proposed. By introducing the root mean square error (RMSE) and coefficient of determination (R²) to evaluate the error and goodness of fit between model curves and experimental data, it is found that the theoretical curves of model in this paper have the best matching with the experimental data. The average values of RMSE and R² for model in this paper are 0.002 and 0.70, respectively, which are better than models in the existing literature.

{"title":"Response properties of geometries of coal penetrating fracture on seepage behavior","authors":"Penghua Han , Kai Wang , Jiewen Pang , Xiaofeng Ji , Cun Zhang","doi":"10.1016/j.ijmst.2025.01.003","DOIUrl":"10.1016/j.ijmst.2025.01.003","url":null,"abstract":"<div><div>The fracture surfaces of coal-rock masses formed under mining-induced stress generally exhibit complex geometries, and the fracture geometry is one of the primary factors affecting the seepage characteristics of coal-rock penetrating fracture. This paper investigates the seepage characteristics of 5 groups of coal penetrating fracture (CPF) with different joint roughness coefficients (JRCs). Based on 3D morphology scanner tests and hydraulic coupling tests, a characterization method of effective geometric parameters in fracture surfaces under various confining pressures was improved, and a relationship between effective geometric parameters and the confining pressure is established. The results indicate that the nonlinear flow behavior in a CPF primarily includes three types: non-Newtonian fluid seepage under high confining pressure and low JRC, non-Darcy seepage under low confining pressure and high JRC, and the whole process of seepage characteristics between these two conditions. Among them, non-Newtonian fluid seepage is caused by significant fracture expansion, while non-Darcy seepage can be attributed to turbulence effects. During the seepage process, the geometric parameters with different JRC fracture samples all exhibit exponential changes with the increase of confining pressure. In addition, under high confining pressure, the effective contact ratio, effective fracture aperture, and void deviation ratio with high JRC fracture samples under high confining pressure increase by 93.5%, 67.4%, and 24.9%, respectively, compared with those of low JRC fracture samples. According to the variation of geometric parameters in a CPF with external stress, a seepage model considering geometric parameters in a CPF is proposed. By introducing the root mean square error (RMSE) and coefficient of determination (<em>R</em><sup>2</sup>) to evaluate the error and goodness of fit between model curves and experimental data, it is found that the theoretical curves of model in this paper have the best matching with the experimental data. The average values of RMSE and <em>R</em><sup>2</sup> for model in this paper are 0.002 and 0.70, respectively, which are better than models in the existing literature.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"35 2","pages":"Pages 191-211"},"PeriodicalIF":11.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529003","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}

引用次数: 0

Macro- and micro-mechanical response and damage mechanism of sandstone under high-temperature conditions

IF 11.7 1区工程技术 Q1 MINING & MINERAL PROCESSING

International Journal of Mining Science and Technology

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmst.2025.01.004

Laiwei Wu , Yanli Huang , Junmeng Li , Guiyuan Wang , Yingshun Li , Xiaotong Li , Junzhi Chen , Chuning Ji

The thermal effects of coal combustion considerably influence the physical and chemical properties, structural characteristics, and stability of rocks, posing a serious threat to the safety of coal mining operations. In this study, the impacts of temperature on the physical and chemical characteristics (i.e., mineral phase, microstructure, and mechanical strength) of sandstone were investigated by employing experimental methods, including microstructural analysis, uniaxial acoustic emission (AE), and nuclear magnetic resonance (NMR). The results indicate that temperature alters the mineral phase and the pore characteristics, and these two factors jointly affect the mechanical properties of sandstone. The influence of temperature on the mechanical strength of sandstone is categorized into low-temperature strengthening and high-temperature damage, with a threshold temperature identified at 600 °C. The low-temperature strengthening effect encompasses both pore strengthening and mineral phase strengthening, while the high-temperature damage effect primarily results from pore damage. As the experimental temperature rises, both the number of AE events and the AE energy transition from a surge in the post-peak failure stage to a stepwise increase during the loading process. This transition implies that the failure mode of the sandstone sample evolves from brittle failure to tensile failure.

{"title":"Macro- and micro-mechanical response and damage mechanism of sandstone under high-temperature conditions","authors":"Laiwei Wu , Yanli Huang , Junmeng Li , Guiyuan Wang , Yingshun Li , Xiaotong Li , Junzhi Chen , Chuning Ji","doi":"10.1016/j.ijmst.2025.01.004","DOIUrl":"10.1016/j.ijmst.2025.01.004","url":null,"abstract":"<div><div>The thermal effects of coal combustion considerably influence the physical and chemical properties, structural characteristics, and stability of rocks, posing a serious threat to the safety of coal mining operations. In this study, the impacts of temperature on the physical and chemical characteristics (i.e., mineral phase, microstructure, and mechanical strength) of sandstone were investigated by employing experimental methods, including microstructural analysis, uniaxial acoustic emission (AE), and nuclear magnetic resonance (NMR). The results indicate that temperature alters the mineral phase and the pore characteristics, and these two factors jointly affect the mechanical properties of sandstone. The influence of temperature on the mechanical strength of sandstone is categorized into low-temperature strengthening and high-temperature damage, with a threshold temperature identified at 600 °C. The low-temperature strengthening effect encompasses both pore strengthening and mineral phase strengthening, while the high-temperature damage effect primarily results from pore damage. As the experimental temperature rises, both the number of AE events and the AE energy transition from a surge in the post-peak failure stage to a stepwise increase during the loading process. This transition implies that the failure mode of the sandstone sample evolves from brittle failure to tensile failure.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"35 2","pages":"Pages 265-274"},"PeriodicalIF":11.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529007","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}

引用次数: 0

Effect of acid fracturing fluid modifying coal microstructure stimulated by ultrasonic

IF 11.7 1区工程技术 Q1 MINING & MINERAL PROCESSING

International Journal of Mining Science and Technology

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmst.2025.01.005

Shaojie Zuo , Rui Gan , Zhijie Wen , Liang Zhang , Zhizhong Jiang , Fuping Zhao , Chengwei Liu , Kun Li , Zhiyuan Xu

The combination of ultrasonic and acid fracturing fluid can strengthen the modification effect on the micropore structure of the coal matrix, thereby enhancing the efficiency of the acid fracturing process. In this research, acetic acid was utilized to formulate acid fracturing fluids with varying concentrations, and the evolutionary traits of both the acid fracturing fluids and ultrasonic waves in relation to coal samples were investigated. The functional group structure, mineral composition, micropore structure and surface morphology of coal samples were characterized by FTIR, XRD, N₂ adsorption at low temperature and SEM-EDS. The results showed that aromatics (I) and branching parameters (CH₂/CH₃) were reduced by 81.58% and 88.67%, respectively, after 9% acetic acid treatment. Acetic acid can dissolve carbonates and clay minerals in coal, create new pores, and increase porosity, pore volume and pore fractal dimension. After modification by 7% acetic acid, the pore volume increased by 5.7 times. SEM observation shows that the diameter of coal surface holes increases, EDS scanning shows that the content of mineral elements in coal decreases, the connectivity of coal holes increases, and the holes expand. The findings of this research offer theoretical direction for optimizing ultrasonic-enhanced acid fracturing fluid modification.

{"title":"Effect of acid fracturing fluid modifying coal microstructure stimulated by ultrasonic","authors":"Shaojie Zuo , Rui Gan , Zhijie Wen , Liang Zhang , Zhizhong Jiang , Fuping Zhao , Chengwei Liu , Kun Li , Zhiyuan Xu","doi":"10.1016/j.ijmst.2025.01.005","DOIUrl":"10.1016/j.ijmst.2025.01.005","url":null,"abstract":"<div><div>The combination of ultrasonic and acid fracturing fluid can strengthen the modification effect on the micropore structure of the coal matrix, thereby enhancing the efficiency of the acid fracturing process. In this research, acetic acid was utilized to formulate acid fracturing fluids with varying concentrations, and the evolutionary traits of both the acid fracturing fluids and ultrasonic waves in relation to coal samples were investigated. The functional group structure, mineral composition, micropore structure and surface morphology of coal samples were characterized by FTIR, XRD, N<sub>2</sub> adsorption at low temperature and SEM-EDS. The results showed that aromatics (<em>I</em>) and branching parameters (CH<sub>2</sub>/CH<sub>3</sub>) were reduced by 81.58% and 88.67%, respectively, after 9% acetic acid treatment. Acetic acid can dissolve carbonates and clay minerals in coal, create new pores, and increase porosity, pore volume and pore fractal dimension. After modification by 7% acetic acid, the pore volume increased by 5.7 times. SEM observation shows that the diameter of coal surface holes increases, EDS scanning shows that the content of mineral elements in coal decreases, the connectivity of coal holes increases, and the holes expand. The findings of this research offer theoretical direction for optimizing ultrasonic-enhanced acid fracturing fluid modification.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"35 2","pages":"Pages 275-293"},"PeriodicalIF":11.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529008","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}

引用次数: 0

Cyclic loading of marble: Correlating the attenuation of the electric and acoustic activities and highlighting criticality indices in terms of natural time 大理石的循环加载：将电活动和声活动的衰减联系起来，突出自然时间的临界指数

IF 11.7 1区工程技术 Q1 MINING & MINERAL PROCESSING

International Journal of Mining Science and Technology

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmst.2024.12.015

Dimos Triantis , Ilias Stavrakas , Ermioni D. Pasiou , Stavros K. Kourkoulis

The attenuation of the acoustic activity in marble specimens under uniaxial compressive loading-unloading loops is quantified in juxtaposition to that of the electric activity. In parallel, the existence of “pre-failure indices” warning about entrance into a critical stage, that of impending fracture, is explored. The acoustic activity is quantified in terms of the normalized number of acoustic hits, their average rate of production and their cumulative energy, and, the cumulative counts and their average rate of change. The electric activity is studied in terms of the pressure stimulated currents and the electric charge released. The analysis revealed that the acoustic and electric activities are linearly correlated to each other, suggesting that they are different manifestations of the same damage mechanisms. In addition, Kaiser’s effect, governing the acoustic activity, is found to govern, also, the electric activity. Moreover, it is concluded that entrance into the critical stage is safely predicted by means of a simple criterion, based on the evolution of the average rate of change of the normalized cumulative counts in the natural time domain. These predictions are almost identical with those of the criterion based on the “variance” and the “entropies” of the time series of acoustic events in this domain.

{"title":"Cyclic loading of marble: Correlating the attenuation of the electric and acoustic activities and highlighting criticality indices in terms of natural time","authors":"Dimos Triantis , Ilias Stavrakas , Ermioni D. Pasiou , Stavros K. Kourkoulis","doi":"10.1016/j.ijmst.2024.12.015","DOIUrl":"10.1016/j.ijmst.2024.12.015","url":null,"abstract":"<div><div>The attenuation of the acoustic activity in marble specimens under uniaxial compressive loading-unloading loops is quantified in juxtaposition to that of the electric activity. In parallel, the existence of “pre-failure indices” warning about entrance into a critical stage, that of impending fracture, is explored. The acoustic activity is quantified in terms of the normalized number of acoustic hits, their average rate of production and their cumulative energy, and, the cumulative counts and their average rate of change. The electric activity is studied in terms of the pressure stimulated currents and the electric charge released. The analysis revealed that the acoustic and electric activities are linearly correlated to each other, suggesting that they are different manifestations of the same damage mechanisms. In addition, Kaiser’s effect, governing the acoustic activity, is found to govern, also, the electric activity. Moreover, it is concluded that entrance into the critical stage is safely predicted by means of a simple criterion, based on the evolution of the average rate of change of the normalized cumulative counts in the natural time domain. These predictions are almost identical with those of the criterion based on the “variance” and the “entropies” of the time series of acoustic events in this domain.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"35 2","pages":"Pages 159-174"},"PeriodicalIF":11.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529002","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}

引用次数: 0

Experimental study on failure precursory characteristics and moisture content effect of pre-cracked rocks under graded cyclic loading and unloading 分级循环加载和卸载下预开裂岩石的破坏前兆特征和含水量效应实验研究

IF 11.7 1区工程技术 Q1 MINING & MINERAL PROCESSING

International Journal of Mining Science and Technology

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmst.2024.12.014

Wei Zhang , Dongxiao Zhang , Weiyao Guo , Baoliang Zhang

It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock mass. Based on digital speckle correlation (DSCM), acoustic emission (AE) and electromagnetic radiation (EMR), uniaxial hierarchical cyclic loading and unloading tests were carried out on sandstones with different fracture numbers under dry, natural and saturated water content, to explore the fracture propagation, failure precursor characteristics and damage response mechanism under the influence of water content effect. The results show that with the increase of water content, the peak stress and crack initiation stress decrease gradually, and the decreases are 15.28%–21.11% and 17.64%–23.04%, respectively. The peak strain and crack initiation strain increase gradually, and the increases are 19.85%–44.53% and 19.15%–41.94%, respectively. The precracked rock with different water content is mainly characterized by tensile failure at different loading stages. However, with the increase of water content, the proportion of shear cracks gradually increases, while acoustic emission events gradually decrease, the dissipative energy and energy storage limits of the rock under peak load gradually decrease, and the charge signal increases significantly, which is because the lubrication effect of water reduces the friction coefficient between crack surfaces.

{"title":"Experimental study on failure precursory characteristics and moisture content effect of pre-cracked rocks under graded cyclic loading and unloading","authors":"Wei Zhang , Dongxiao Zhang , Weiyao Guo , Baoliang Zhang","doi":"10.1016/j.ijmst.2024.12.014","DOIUrl":"10.1016/j.ijmst.2024.12.014","url":null,"abstract":"<div><div>It is important to analyze the damage evolution process of surrounding rock under different water content for the stability of engineering rock mass. Based on digital speckle correlation (DSCM), acoustic emission (AE) and electromagnetic radiation (EMR), uniaxial hierarchical cyclic loading and unloading tests were carried out on sandstones with different fracture numbers under dry, natural and saturated water content, to explore the fracture propagation, failure precursor characteristics and damage response mechanism under the influence of water content effect. The results show that with the increase of water content, the peak stress and crack initiation stress decrease gradually, and the decreases are 15.28%–21.11% and 17.64%–23.04%, respectively. The peak strain and crack initiation strain increase gradually, and the increases are 19.85%–44.53% and 19.15%–41.94%, respectively. The precracked rock with different water content is mainly characterized by tensile failure at different loading stages. However, with the increase of water content, the proportion of shear cracks gradually increases, while acoustic emission events gradually decrease, the dissipative energy and energy storage limits of the rock under peak load gradually decrease, and the charge signal increases significantly, which is because the lubrication effect of water reduces the friction coefficient between crack surfaces.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"35 2","pages":"Pages 249-264"},"PeriodicalIF":11.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529006","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}

引用次数: 0

Advancing the recovery of iron and rare earth elements from the solid waste at Bayan Obo 推进从巴彦奥博固体废物中回收铁和稀土元素的工作

IF 11.7 1区工程技术 Q1 MINING & MINERAL PROCESSING

International Journal of Mining Science and Technology

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmst.2024.12.006

Na Zhao , Qiang Zhang , Hongwei Ma , Yongsheng Sun , Peng Gao , Zhao Cao , Zhenyue Zhang

The storage of solid waste in Bayan Obo has resulted in significant resource wastage and environmental concerns. In this study, an efficient process was developed to recover iron and rare earth elements (REEs) from this waste by processes of hydrogen-based mineral phase transformation (HMPT), magnetic separation, and flotation. Under optimal HMPT conditions (525 °C, 12.5 min, and 30% H₂ concentration), an iron concentrate with a TFe grade of 64.09% and a recovery of 95.33% was obtained. The magnetic properties of the solid waste were greatly enhanced by HMPT, allowing the effective magnetic separation of iron minerals. Further optimization of the flotation process resulted in a REEs concentrate with a rare earth oxide (REO) grade of 65%–70% and a REEs recovery of 60%–65%. Hematite was reduced to magnetite during HMPT, and bastnaesite was decomposed to REEs oxides and fluorides, and the particle structure was significantly destroyed. However, changes in monazite, fluorite, and barite were minimal.

{"title":"Advancing the recovery of iron and rare earth elements from the solid waste at Bayan Obo","authors":"Na Zhao , Qiang Zhang , Hongwei Ma , Yongsheng Sun , Peng Gao , Zhao Cao , Zhenyue Zhang","doi":"10.1016/j.ijmst.2024.12.006","DOIUrl":"10.1016/j.ijmst.2024.12.006","url":null,"abstract":"<div><div>The storage of solid waste in Bayan Obo has resulted in significant resource wastage and environmental concerns. In this study, an efficient process was developed to recover iron and rare earth elements (REEs) from this waste by processes of hydrogen-based mineral phase transformation (HMPT), magnetic separation, and flotation. Under optimal HMPT conditions (525 °C, 12.5 min, and 30% H<sub>2</sub> concentration), an iron concentrate with a TFe grade of 64.09% and a recovery of 95.33% was obtained. The magnetic properties of the solid waste were greatly enhanced by HMPT, allowing the effective magnetic separation of iron minerals. Further optimization of the flotation process resulted in a REEs concentrate with a rare earth oxide (REO) grade of 65%–70% and a REEs recovery of 60%–65%. Hematite was reduced to magnetite during HMPT, and bastnaesite was decomposed to REEs oxides and fluorides, and the particle structure was significantly destroyed. However, changes in monazite, fluorite, and barite were minimal.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"35 2","pages":"Pages 295-306"},"PeriodicalIF":11.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529009","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}

引用次数: 0

Investigation on coal damage and fracture extension law of liquid nitrogen injection pre-cooling and fracturing under true triaxial stress

IF 11.7 1区工程技术 Q1 MINING & MINERAL PROCESSING

International Journal of Mining Science and Technology

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmst.2024.12.013

Botao Li , Haifei Lin , Jianping Wei , Hongtu Zhang , Shugang Li , Zongyong Wei , Lei Qin , Pei Wang , Rongwei Luo , Zeran Liu

To more accurately describe the coal damage and fracture evolution law during liquid nitrogen (LN₂) fracturing under true triaxial stress, a thermal–hydraulic-mechanical-damage (THMD) coupling model for LN₂ fracturing coal was developed, considering the coal heterogeneity and thermophysical parameters of nitrogen. The accuracy and applicability of model were verified by comparing with LN₂ injection pre-cooling and fracturing experimental data. The effects of different pre-cooling times and horizontal stress ratios on coal damage evolution, permeability, temperature distribution, and fracture characteristics were analyzed. The results show that the permeability and damage of the coal increase exponentially, while the temperature decreases exponentially during the fracturing process. As the pre-cooling time increases, the damage range of the coal expands, and the fracture propagation becomes more pronounced. The initiation pressure and rupture pressure decrease and tend to stabilize with longer pre-cooling times. As the horizontal stress ratio increases, fractures preferentially extend along the direction of maximum horizontal principal stress, leading to a significant decrease in both initiation and rupture pressures. At a horizontal stress ratio of 3, the initiation pressure drops by 48.07%, and the rupture pressure decreases by 41.36%. The results provide a theoretical basis for optimizing LN₂ fracturing techniques and improving coal seam modification.

{"title":"Investigation on coal damage and fracture extension law of liquid nitrogen injection pre-cooling and fracturing under true triaxial stress","authors":"Botao Li , Haifei Lin , Jianping Wei , Hongtu Zhang , Shugang Li , Zongyong Wei , Lei Qin , Pei Wang , Rongwei Luo , Zeran Liu","doi":"10.1016/j.ijmst.2024.12.013","DOIUrl":"10.1016/j.ijmst.2024.12.013","url":null,"abstract":"<div><div>To more accurately describe the coal damage and fracture evolution law during liquid nitrogen (LN<sub>2</sub>) fracturing under true triaxial stress, a thermal–hydraulic-mechanical-damage (THMD) coupling model for LN<sub>2</sub> fracturing coal was developed, considering the coal heterogeneity and thermophysical parameters of nitrogen. The accuracy and applicability of model were verified by comparing with LN<sub>2</sub> injection pre-cooling and fracturing experimental data. The effects of different pre-cooling times and horizontal stress ratios on coal damage evolution, permeability, temperature distribution, and fracture characteristics were analyzed. The results show that the permeability and damage of the coal increase exponentially, while the temperature decreases exponentially during the fracturing process. As the pre-cooling time increases, the damage range of the coal expands, and the fracture propagation becomes more pronounced. The initiation pressure and rupture pressure decrease and tend to stabilize with longer pre-cooling times. As the horizontal stress ratio increases, fractures preferentially extend along the direction of maximum horizontal principal stress, leading to a significant decrease in both initiation and rupture pressures. At a horizontal stress ratio of 3, the initiation pressure drops by 48.07%, and the rupture pressure decreases by 41.36%. The results provide a theoretical basis for optimizing LN<sub>2</sub> fracturing techniques and improving coal seam modification.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"35 2","pages":"Pages 213-229"},"PeriodicalIF":11.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529004","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}

引用次数: 0

Bond length and interface failure mechanism of anchor cable under continuous radial pressure conditions

IF 11.7 1区工程技术 Q1 MINING & MINERAL PROCESSING

International Journal of Mining Science and Technology

Pub Date : 2025-02-01 DOI: 10.1016/j.ijmst.2025.01.001

Jian Ouyang, Xiuzhi Shi, Xianyang Qiu, Zongguo Zhang, Zeyu Li

The anchoring capacity of the anchor cable is closely related to the bonding length and radial pressure conditions. Through field pull-out tests, theoretical analysis, numerical simulation, and industrial tests, this study clarifies the relationship between radial pressure and bonding length for the ultimate pull-out force and reveals the microscopic failure process of the resin-rock interface in the anchoring system. The results show that the ultimate load increases with the increase of bonding length in three different stages: rapid, slow, and uniform growth. The new mechanical model developed considering radial pressure describes the inverse relationship between radial pressure and the plastic zone on the bonding section, and quantifies the reinforcing effect of confining pressure on the anchoring force. During the pull-out process of the anchor cable, the generation of failure cracks is in the order of orifice, bottom, and middle of the hole. Radial pressure can effectively enhance the ultimate pull-out force, alleviate the oscillation increase of pull-out force, and inhibit resin cracking, but will produce an external crushing zone. It also reveals the synergistic effect between bonding length and radial pressure, and successfully carries out industrial tests of anchor cable support, which ensures the stability of the stope roof and provides an important reference for the design of anchor cable support in deep high-stress mines.

{"title":"Bond length and interface failure mechanism of anchor cable under continuous radial pressure conditions","authors":"Jian Ouyang, Xiuzhi Shi, Xianyang Qiu, Zongguo Zhang, Zeyu Li","doi":"10.1016/j.ijmst.2025.01.001","DOIUrl":"10.1016/j.ijmst.2025.01.001","url":null,"abstract":"<div><div>The anchoring capacity of the anchor cable is closely related to the bonding length and radial pressure conditions. Through field pull-out tests, theoretical analysis, numerical simulation, and industrial tests, this study clarifies the relationship between radial pressure and bonding length for the ultimate pull-out force and reveals the microscopic failure process of the resin-rock interface in the anchoring system. The results show that the ultimate load increases with the increase of bonding length in three different stages: rapid, slow, and uniform growth. The new mechanical model developed considering radial pressure describes the inverse relationship between radial pressure and the plastic zone on the bonding section, and quantifies the reinforcing effect of confining pressure on the anchoring force. During the pull-out process of the anchor cable, the generation of failure cracks is in the order of orifice, bottom, and middle of the hole. Radial pressure can effectively enhance the ultimate pull-out force, alleviate the oscillation increase of pull-out force, and inhibit resin cracking, but will produce an external crushing zone. It also reveals the synergistic effect between bonding length and radial pressure, and successfully carries out industrial tests of anchor cable support, which ensures the stability of the stope roof and provides an important reference for the design of anchor cable support in deep high-stress mines.</div></div>","PeriodicalId":48625,"journal":{"name":"International Journal of Mining Science and Technology","volume":"35 2","pages":"Pages 231-247"},"PeriodicalIF":11.7,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143529005","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}

引用次数: 0