Geologic surface approximation is profoundly affected by the presence, density and location of scattered geologic input data. Many studies have recognized the importance of utilizing varied sources of information when...Geologic surface approximation is profoundly affected by the presence, density and location of scattered geologic input data. Many studies have recognized the importance of utilizing varied sources of information when reconstructing a surface. This paper presents an improved geologic surface approximation method using a multiquadric function and borehole data. Additional information, i.e., inequality elevation and dip-strikes data extracted from outcrops or mining faces, is introduced in the form of physical constraints that control local changes in the estimated surface. Commonly accepted hypothesis states that geologic surfaces can be approximated to any desired degree of exactness by the summation of regular, mathematically defined, surfaces: in particular displaced quadric forms. The coefficients of the multiquadric functions are traditionally found by a least squares method. The addition of physical constraints in this work makes such an approach into a non-deterministic polynomial time problem. Hence we propose an objective function that represents the quality of the estimated surface and that includes the additional constraints by incorporation of a penalty function. Maximizing the smoothness of the estimated surface and its fitness to the additional constraints then allows the coefficients of the multiquadric function to be obtained by iterative methods. This method was implemented and demonstrated using data collected from the 81'st coal mining area of the Huaibei Coal Group.展开更多
Difficulties with soft coal seams having a high gas content and high stress levels can be addressed by a technology of pressure relief and permeability increase.Slotting the seam by auxiliary drilling with a water jet...Difficulties with soft coal seams having a high gas content and high stress levels can be addressed by a technology of pressure relief and permeability increase.Slotting the seam by auxiliary drilling with a water jet that breaks the coal and slots the coal seam during the process of retreat drilling achieves pressure relief and permeability increase.Improved efficiency of gas extraction from a field test,high gas coal seam was observed.Investigating the theory of pressure relief and permeability increase required analyzing the characteristics of the double power slotting process and the effects of coal pressure relief and permeability increase.The influence of confining pressure on coal physical properties was examined by using FLAC3D software code to simulate changes of coal stress within the tool destruction area.The double power joint drilling method was modeled.Field experiments were performed and the effects are analyzed.This research shows that there is an ''islanding effect'' in front of the joint double power drill and slotting equipment.The failure strength of the coal seam is substantially reduced within the tool destruction area.Drilling depths are increased by 72% and the diameter of the borehole is increased by 30%.The amount of powdered coal extracted from the drill head increases by 17 times when using the new method.A 30 day total flow measurement from the double power drilled and slotted bores showed that gas extraction increased by 1.3 times compared to the standard drilled bores.Gas concentrations increased from 30% to 60% and were more stable so the overall extraction efficiency increased by a factor of two times.展开更多
Emission of large amount of SO2 from combustion of liigh sulfur ctal causes serious envitonmcntai pollution. Pre-combustion desunrization of high sulfur coal has become a necessity.Thts paper reports test results of f...Emission of large amount of SO2 from combustion of liigh sulfur ctal causes serious envitonmcntai pollution. Pre-combustion desunrization of high sulfur coal has become a necessity.Thts paper reports test results of fine coal dcaulfurization with different flotation technology and theeffect of pyrite depressant. Test work showed that when the coal sample from Zhong Liang Shanwas processed with a Free Jet Flotation Column its pyritic sulfur content was reduced from 3.08%to 0. 84%, with 72. 22% recovery ofcomhustiblc matter in clean coal. The coneept of Desulfuriza tion Efficiency Index E for comprehensive evaluation of desumirhation process is proposed, whichis deffeed as the product of the ratio of sulfur content reduction of clean ctal and the recovery ofcomhustihle matters.展开更多
Gateways at faces of great mining heights are mostly driven along the roof of coal seams.For gateway height restrictions,a 1-3 m floor coal is retained,leaving a triangular floor coal at the face ends,causing a loss o...Gateways at faces of great mining heights are mostly driven along the roof of coal seams.For gateway height restrictions,a 1-3 m floor coal is retained,leaving a triangular floor coal at the face ends,causing a loss of coal.In order to improve coal recovery rates and to ensure efficiency of equipment at coal mining faces,we investigated suitable retention methods and recovery technology of floor coal at face ends.The upper floor coal can directly be recovered by a shearer with floor dinting.The lower floor coal is recovered by shearer with floor dinting after advanced floor dinting and retaining a step for protecting coal sides in a haulage gateway.Field practice shows that this method can improve the coal recovery rates at fully mechanized working faces with great mining heights.展开更多
This study was performed to investigate the spectral characteristics of micro-seismic signals observed during the rupture of coal. Coal rupture micro-seismic observations were obtained on a test system that included a...This study was performed to investigate the spectral characteristics of micro-seismic signals observed during the rupture of coal. Coal rupture micro-seismic observations were obtained on a test system that included an electro-hydraulic servo pressure tester controlled by a YAW microcomputer, a micro-seismic sensor, a loading system, and a signal collection system. The results show that the micro-seismic signal increases with increasing compressive stress at the beginning of coal rupture. The signal remains stable for a period at this stage. A large number of micro-seismic signals appear immediately before the main rupture event. The frequency of micro-seismic events reaches a maximum immediately after the coal ruptures. Micro-seismic signals were decomposed into several Intrinsic Mode Functions (IMF's) by the empirical mode decomposition (EMD) method using a Hilbert-Huang transform (HHT). The main fre- quency band of the micro-seismic signals was found to range from 10 to 100 Hz in the Hilbert energy spectrum and from marginal spectrum calculations. The advantage of applying an HHT is that this can extract the main features of the signal. This fact was confirmed by an HHT analysis of the coal micro-seis- mic signals that shows the technique is useful in the field of coal rupture.展开更多
The sustainable development of coal mining cities in Heilongjiang province has important effect on the economic stability and development of Heilongjiang, Northeast China, and China at large. To further the sustainabl...The sustainable development of coal mining cities in Heilongjiang province has important effect on the economic stability and development of Heilongjiang, Northeast China, and China at large. To further the sustainable development evaluation system of coal mining cities in Heilongjiang province, based on the analytic hierarchy process （AHP） method combined with operational and scientific principles using Saaty＇s 1-9 scale method to construct the judgment matrix from five aspects, such as economic development and environmental quality, this paper establishes the comprehensive evaluation index sys- tem of sustainable development of coal mining cities in Heilongjiang province, including comprehensive index of industrial economic benefits and the contribution rate of science and technology. In addition, using fuzzy comprehensive evaluation method, a comprehensive evaluation is made on the indices of the four major coal mining cities of Heilongjiang. The result shows that the coal mining cities are not bet- ter than Datong of Shanxi province in many indices. The economic development and environment quality are the most important indices of the targeted layer influencing the sustainable development of coal min- ing cities of HeilonKiiang, and their index weights are 0.4358 and 0.2844, respectively. These two indices including comprehensive index of industrial economic benefit and the ratio of environmental protection investment to GDP are the key elements influencing the two aspects.展开更多
基金provided by the National Science and Technology Major Project of China (Nos.2009ZX05039-004 and 2009ZX 05039-002)the National Natural Science Foundation of China (Nos.40771167 and 70621001)
文摘Geologic surface approximation is profoundly affected by the presence, density and location of scattered geologic input data. Many studies have recognized the importance of utilizing varied sources of information when reconstructing a surface. This paper presents an improved geologic surface approximation method using a multiquadric function and borehole data. Additional information, i.e., inequality elevation and dip-strikes data extracted from outcrops or mining faces, is introduced in the form of physical constraints that control local changes in the estimated surface. Commonly accepted hypothesis states that geologic surfaces can be approximated to any desired degree of exactness by the summation of regular, mathematically defined, surfaces: in particular displaced quadric forms. The coefficients of the multiquadric functions are traditionally found by a least squares method. The addition of physical constraints in this work makes such an approach into a non-deterministic polynomial time problem. Hence we propose an objective function that represents the quality of the estimated surface and that includes the additional constraints by incorporation of a penalty function. Maximizing the smoothness of the estimated surface and its fitness to the additional constraints then allows the coefficients of the multiquadric function to be obtained by iterative methods. This method was implemented and demonstrated using data collected from the 81'st coal mining area of the Huaibei Coal Group.
基金supports provided by the National Key Basic Research and Development Program of China (No. 2011CB201205)the National Natural Science Foundation of China (No. 51074161)the Independent research of State Key Laboratory of Coal Resources and Mine Safety of China University of Mining & Technology (No. SKLCRSM08X03)
文摘Difficulties with soft coal seams having a high gas content and high stress levels can be addressed by a technology of pressure relief and permeability increase.Slotting the seam by auxiliary drilling with a water jet that breaks the coal and slots the coal seam during the process of retreat drilling achieves pressure relief and permeability increase.Improved efficiency of gas extraction from a field test,high gas coal seam was observed.Investigating the theory of pressure relief and permeability increase required analyzing the characteristics of the double power slotting process and the effects of coal pressure relief and permeability increase.The influence of confining pressure on coal physical properties was examined by using FLAC3D software code to simulate changes of coal stress within the tool destruction area.The double power joint drilling method was modeled.Field experiments were performed and the effects are analyzed.This research shows that there is an ''islanding effect'' in front of the joint double power drill and slotting equipment.The failure strength of the coal seam is substantially reduced within the tool destruction area.Drilling depths are increased by 72% and the diameter of the borehole is increased by 30%.The amount of powdered coal extracted from the drill head increases by 17 times when using the new method.A 30 day total flow measurement from the double power drilled and slotted bores showed that gas extraction increased by 1.3 times compared to the standard drilled bores.Gas concentrations increased from 30% to 60% and were more stable so the overall extraction efficiency increased by a factor of two times.
文摘Emission of large amount of SO2 from combustion of liigh sulfur ctal causes serious envitonmcntai pollution. Pre-combustion desunrization of high sulfur coal has become a necessity.Thts paper reports test results of fine coal dcaulfurization with different flotation technology and theeffect of pyrite depressant. Test work showed that when the coal sample from Zhong Liang Shanwas processed with a Free Jet Flotation Column its pyritic sulfur content was reduced from 3.08%to 0. 84%, with 72. 22% recovery ofcomhustiblc matter in clean coal. The coneept of Desulfuriza tion Efficiency Index E for comprehensive evaluation of desumirhation process is proposed, whichis deffeed as the product of the ratio of sulfur content reduction of clean ctal and the recovery ofcomhustihle matters.
基金the Independent Research of the State Key Laboratory of Coal Resources and Mine Safety(No. SKLCRSM09X02)the Open Research Fund of the State Key Laboratory of Coal Resources and Mine Safety(No.08KF12)the Graduate Students of Jiangsu Province Innovation Program Funded Projects(No.CX09B_120Z) for their financial support
文摘Gateways at faces of great mining heights are mostly driven along the roof of coal seams.For gateway height restrictions,a 1-3 m floor coal is retained,leaving a triangular floor coal at the face ends,causing a loss of coal.In order to improve coal recovery rates and to ensure efficiency of equipment at coal mining faces,we investigated suitable retention methods and recovery technology of floor coal at face ends.The upper floor coal can directly be recovered by a shearer with floor dinting.The lower floor coal is recovered by shearer with floor dinting after advanced floor dinting and retaining a step for protecting coal sides in a haulage gateway.Field practice shows that this method can improve the coal recovery rates at fully mechanized working faces with great mining heights.
基金support for this work provided by the National Science and Technology Planning Project (No. 2009BAK54B03)the National Natural Science Foundation of China (No. 50834005)
文摘This study was performed to investigate the spectral characteristics of micro-seismic signals observed during the rupture of coal. Coal rupture micro-seismic observations were obtained on a test system that included an electro-hydraulic servo pressure tester controlled by a YAW microcomputer, a micro-seismic sensor, a loading system, and a signal collection system. The results show that the micro-seismic signal increases with increasing compressive stress at the beginning of coal rupture. The signal remains stable for a period at this stage. A large number of micro-seismic signals appear immediately before the main rupture event. The frequency of micro-seismic events reaches a maximum immediately after the coal ruptures. Micro-seismic signals were decomposed into several Intrinsic Mode Functions (IMF's) by the empirical mode decomposition (EMD) method using a Hilbert-Huang transform (HHT). The main fre- quency band of the micro-seismic signals was found to range from 10 to 100 Hz in the Hilbert energy spectrum and from marginal spectrum calculations. The advantage of applying an HHT is that this can extract the main features of the signal. This fact was confirmed by an HHT analysis of the coal micro-seis- mic signals that shows the technique is useful in the field of coal rupture.
基金supported by the Philosophy and Social Science Program of Heilongjiang Province (No. 10D051)the Science and Technology Plan Program of Heilongjiang Province (No. GC10D209)the General Humanity and Social Science Program of Heilongjiang Provincial Universities in 2012 (HET-based energy sustainable development research of Heilongjiang province) (No. 12522258)
文摘The sustainable development of coal mining cities in Heilongjiang province has important effect on the economic stability and development of Heilongjiang, Northeast China, and China at large. To further the sustainable development evaluation system of coal mining cities in Heilongjiang province, based on the analytic hierarchy process （AHP） method combined with operational and scientific principles using Saaty＇s 1-9 scale method to construct the judgment matrix from five aspects, such as economic development and environmental quality, this paper establishes the comprehensive evaluation index sys- tem of sustainable development of coal mining cities in Heilongjiang province, including comprehensive index of industrial economic benefits and the contribution rate of science and technology. In addition, using fuzzy comprehensive evaluation method, a comprehensive evaluation is made on the indices of the four major coal mining cities of Heilongjiang. The result shows that the coal mining cities are not bet- ter than Datong of Shanxi province in many indices. The economic development and environment quality are the most important indices of the targeted layer influencing the sustainable development of coal min- ing cities of HeilonKiiang, and their index weights are 0.4358 and 0.2844, respectively. These two indices including comprehensive index of industrial economic benefit and the ratio of environmental protection investment to GDP are the key elements influencing the two aspects.
