No.4326 super-wide panel of Wangzhuang Coal Mine ( in which the fully-mechanized top-coal caving longwall mining method was used) was monitored for dynamic characteristic of surface movement. The dynamic surface movem...No.4326 super-wide panel of Wangzhuang Coal Mine ( in which the fully-mechanized top-coal caving longwall mining method was used) was monitored for dynamic characteristic of surface movement. The dynamic surface movement in and after mining was predicted by using the Mining Subsidence Prediction System. The results indicate that after mining, the surface above the super-wide panel reaches a state of full subsidence, making the No.309 national highway above the panel be located on the flat bottom of the subsidence basin so that the influence of mining activity in both sides of 4326 panel on the national highway is the smallest.展开更多
A combined method of numerical simulation and field testing was adopted in this study in the interest of solving the problem of hard to control high concentrate dusts on a fully mechanized mining face. In addi- tion, ...A combined method of numerical simulation and field testing was adopted in this study in the interest of solving the problem of hard to control high concentrate dusts on a fully mechanized mining face. In addi- tion, the dust suppression effect of a multi-direction whirling air curtain was studied in this paper. Under the influence of the wall attachment effect, the compressed air which blows out from the two-phase or three-phase radial outlets on the generator of the air curtain can form a multi-direction whirling air curtain, which can cover the whole roadway section of a fully mechanized mining face. The traditional method of controlling dust is a forcing system with exhaust overlap which has the major disadvantage of lacking a jet effect and consequently results in poor dust control. It is difficult to form the air flow field within the range of Lp ≤ 5√S. However, due to the effect of this novel system, the radial airflow can be turned into axial airflow allowing fresh air to flow through the length of the heading. The air flow field which is good at controlling dust diffusion can be formed 12.8 m from the heading face. Furthermore, the field measurement results show that before the application of a multi-direction whirling air curtain, the dust concentration is 348.6 mg/m^3 and 271.4 mg/m^3 respectively at the roadway cross-section measurement points which are 5 m and 10 m from the heading face. However, after the application of the multi-direction whirling air curtain, the dust concentration is only 61.2 mg/m3 and 14.8 mg/m^3, respectively. Therefore, the dust control effect of a multi-direction whirling air curtain is obvious.展开更多
Given the actual working of a fully mechanized plough at a mining face, we have proposed a formula for running constraints between powered supports and a coal plough under assumed geological conditions of the coal fac...Given the actual working of a fully mechanized plough at a mining face, we have proposed a formula for running constraints between powered supports and a coal plough under assumed geological conditions of the coal face and, on this basis, established an automatic control model of powered supports for the coal plough face. We introduced the working principle of the powered support control system of the plough at the mining face. We established three advanced characteristics of this control system： response speed, reliability and easy maintenance of the system. As well, we briefly introduced, the principal function of primary and subordinate controllers and the realization of the communication system by a Single Bus. Ten controllers were constructed and tested in our laboratorium. The results show that the control model is practical and meets actual conditions. It provides a theoretical basis for designing a comouter control system for a oowered support system of a plough at a mining face.展开更多
To investigate the abnormal ground pressures and roof control problem in fully mechanized repeated mining of residual coal after room and pillar mining, the roof fracture structural model and mechanical model were dev...To investigate the abnormal ground pressures and roof control problem in fully mechanized repeated mining of residual coal after room and pillar mining, the roof fracture structural model and mechanical model were developed using numerical simulation and theoretical analysis. The roof fracture characteristics of a repeated mining face were revealed and the ground pressure law and roof supporting condi- tions of the repeated mining face were obtained. The results indicate that when the repeated mining face passes the residual pillars, the sudden instability causes fracturing in the main roof above the old goal and forms an extra-large rock block above the mining face. A relatively stable ＂Voussoir beam＂ structure is formed after the advance fracturing of the main roof. When the repeated mining face passes the old goaf, as the large rock block revolves and touches gangue, the rock block will break secondarily under overburden rock loads. An example calculation was performed involving an integrated mine in Shanxi province, results showed that minimum working resistance values of support determined to be reason- able were respectively 11,412 kN and 10,743 kN when repeated mining face passed through residual pillar and goaf. On-site ground pressure monitoring results indicated that the mechanical model and support resistance calculation were reasonable.展开更多
Knowledge of the airflow patterns and methane distributions at a continuous miner face under different ventilation conditions can minimize the risks of explosion and injury to miners by accurately forecasting potentia...Knowledge of the airflow patterns and methane distributions at a continuous miner face under different ventilation conditions can minimize the risks of explosion and injury to miners by accurately forecasting potentially hazardous face methane levels. This study focused on validating a series of computational fluid dynamics(CFD) models using full-scale ventilation gallery data that assessed how curtain setback distance impacted airflow patterns and methane distributions at an empty mining face(no continuous miner present). Three CFD models of face ventilation with 4.6, 7.6 and 10.7 m(15, 25, and 35 ft) blowing curtain setback distances were constructed and validated with experimental data collected in a full-scale ventilation test facility. Good agreement was obtained between the CFD simulation results and this data.Detailed airflow and methane distribution information are provided. Elevated methane zones at the working faces were identified with the three curtain setback distances. Visualization of the setback distance impact on the face methane distribution was performed by utilizing the post-processing capability of the CFD software.展开更多
Based on the neural network technique, this paper proposes a BP neural network model which integrates geological factors which affect top coal caving in a comprehensive index. The index of top coal caving may be used ...Based on the neural network technique, this paper proposes a BP neural network model which integrates geological factors which affect top coal caving in a comprehensive index. The index of top coal caving may be used to forecast the mining cost of working faces, which shows the model’s potential prospect of applications.展开更多
文摘No.4326 super-wide panel of Wangzhuang Coal Mine ( in which the fully-mechanized top-coal caving longwall mining method was used) was monitored for dynamic characteristic of surface movement. The dynamic surface movement in and after mining was predicted by using the Mining Subsidence Prediction System. The results indicate that after mining, the surface above the super-wide panel reaches a state of full subsidence, making the No.309 national highway above the panel be located on the flat bottom of the subsidence basin so that the influence of mining activity in both sides of 4326 panel on the national highway is the smallest.
基金supported by the Key Program of the Coal Joint Funds of the National Natural Science Foundation of China (No.U1261205)the Youth Program of National Natural Science Foundation of China (No.51404147)+2 种基金the Class General Financial Grant from the China Postdoctoral Science Foundation (No.2015M570601)the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents (No.2014RCJJ029)the State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science and Technology,Shandong University of Science and Technology (No.MDPC2013ZR02)
文摘A combined method of numerical simulation and field testing was adopted in this study in the interest of solving the problem of hard to control high concentrate dusts on a fully mechanized mining face. In addi- tion, the dust suppression effect of a multi-direction whirling air curtain was studied in this paper. Under the influence of the wall attachment effect, the compressed air which blows out from the two-phase or three-phase radial outlets on the generator of the air curtain can form a multi-direction whirling air curtain, which can cover the whole roadway section of a fully mechanized mining face. The traditional method of controlling dust is a forcing system with exhaust overlap which has the major disadvantage of lacking a jet effect and consequently results in poor dust control. It is difficult to form the air flow field within the range of Lp ≤ 5√S. However, due to the effect of this novel system, the radial airflow can be turned into axial airflow allowing fresh air to flow through the length of the heading. The air flow field which is good at controlling dust diffusion can be formed 12.8 m from the heading face. Furthermore, the field measurement results show that before the application of a multi-direction whirling air curtain, the dust concentration is 348.6 mg/m^3 and 271.4 mg/m^3 respectively at the roadway cross-section measurement points which are 5 m and 10 m from the heading face. However, after the application of the multi-direction whirling air curtain, the dust concentration is only 61.2 mg/m3 and 14.8 mg/m^3, respectively. Therefore, the dust control effect of a multi-direction whirling air curtain is obvious.
基金Project 104030 supported by the Ministry of Education of the People’s Republic of China
文摘Given the actual working of a fully mechanized plough at a mining face, we have proposed a formula for running constraints between powered supports and a coal plough under assumed geological conditions of the coal face and, on this basis, established an automatic control model of powered supports for the coal plough face. We introduced the working principle of the powered support control system of the plough at the mining face. We established three advanced characteristics of this control system： response speed, reliability and easy maintenance of the system. As well, we briefly introduced, the principal function of primary and subordinate controllers and the realization of the communication system by a Single Bus. Ten controllers were constructed and tested in our laboratorium. The results show that the control model is practical and meets actual conditions. It provides a theoretical basis for designing a comouter control system for a oowered support system of a plough at a mining face.
基金the National Basic Research Program of China (No.2014CB046905)Innovation Project for Graduates in Jiangsu Province (No.KYLX15_1405)+1 种基金the National Natural Science Foundation of China (Nos.51274191 and 51404245)the Doctoral Fund of Ministry of Education of China (No.20130095110018)
文摘To investigate the abnormal ground pressures and roof control problem in fully mechanized repeated mining of residual coal after room and pillar mining, the roof fracture structural model and mechanical model were developed using numerical simulation and theoretical analysis. The roof fracture characteristics of a repeated mining face were revealed and the ground pressure law and roof supporting condi- tions of the repeated mining face were obtained. The results indicate that when the repeated mining face passes the residual pillars, the sudden instability causes fracturing in the main roof above the old goal and forms an extra-large rock block above the mining face. A relatively stable ＂Voussoir beam＂ structure is formed after the advance fracturing of the main roof. When the repeated mining face passes the old goaf, as the large rock block revolves and touches gangue, the rock block will break secondarily under overburden rock loads. An example calculation was performed involving an integrated mine in Shanxi province, results showed that minimum working resistance values of support determined to be reason- able were respectively 11,412 kN and 10,743 kN when repeated mining face passed through residual pillar and goaf. On-site ground pressure monitoring results indicated that the mechanical model and support resistance calculation were reasonable.
文摘Knowledge of the airflow patterns and methane distributions at a continuous miner face under different ventilation conditions can minimize the risks of explosion and injury to miners by accurately forecasting potentially hazardous face methane levels. This study focused on validating a series of computational fluid dynamics(CFD) models using full-scale ventilation gallery data that assessed how curtain setback distance impacted airflow patterns and methane distributions at an empty mining face(no continuous miner present). Three CFD models of face ventilation with 4.6, 7.6 and 10.7 m(15, 25, and 35 ft) blowing curtain setback distances were constructed and validated with experimental data collected in a full-scale ventilation test facility. Good agreement was obtained between the CFD simulation results and this data.Detailed airflow and methane distribution information are provided. Elevated methane zones at the working faces were identified with the three curtain setback distances. Visualization of the setback distance impact on the face methane distribution was performed by utilizing the post-processing capability of the CFD software.
文摘Based on the neural network technique, this paper proposes a BP neural network model which integrates geological factors which affect top coal caving in a comprehensive index. The index of top coal caving may be used to forecast the mining cost of working faces, which shows the model’s potential prospect of applications.
