During advanced water detection using the transient electromagnetic method, the exploration effect for water-rich area is often poor due to the interference of bolts that are distributed in different positions in work...During advanced water detection using the transient electromagnetic method, the exploration effect for water-rich area is often poor due to the interference of bolts that are distributed in different positions in working face. Thus, the study on the interference characteristics of bolts in different states has important directive significance for improving the acquisition quality and data processing method in water detection. Based on the analysis of the distribution laws of magnetic field excited by small multi-turn coincident loop in full space of homogeneity, the test on the interference of bolts has been designed in the mine. Through drilling 18 holes around the overlapping coil in the working face, mass data are collected in order with the posi- tion change and the exposed bolt length. The results of comprehensive data analysis show that the transient electromagnetic field is strongly interfered as the distance between the bolt and the center of the coil is less than 3 m, and the interference varies greatly as the distance varies. On the other hand, the field induced by the bolts can be ignored as the distance exceeds 3 m. The findings can help to improve data acquisition and correction during advanced water detection when using the transient electromagnetic method.展开更多
Well logging technology in coalbed methane （CBM） exploration may develop in two directions： one is the novel well logging methods; the other is the new interpretation methods for the conventional logging data, on w...Well logging technology in coalbed methane （CBM） exploration may develop in two directions： one is the novel well logging methods; the other is the new interpretation methods for the conventional logging data, on which the authors of this paper concentrated mainly. The paper introduced several methods in calculating with well logs such important parameters as porosity, permeability and gas content of CBM reservoir and evaluated their effectiveness. A new method of well logging data interpretation was put forward for coalbed recognition, i.e., the combination of the principal component analysis and the wavelet transform. The authors find that the second principal component （PCA2） contains much more information of coalbed in the coal-bearing series and the reconstruction signal from the detailed wavelet coefficients at level 4 （PCA24） and 5 （PCA25） highlights the signature ofcoalbeds. In terms of the characteristics of CBM reservoir in China, the authors summarized the key points in the application of well logging technique to CBM exploration, and gave a guideline for further related research work.展开更多
There are many potential hazards in the underground mining these include fire, explosion, inundation, roof collapse, toxic gases, chemical pollution, etc. Over past centuries, in US alone, more than 100 000 miners los...There are many potential hazards in the underground mining these include fire, explosion, inundation, roof collapse, toxic gases, chemical pollution, etc. Over past centuries, in US alone, more than 100 000 miners lost their life in different accidents. The primary safety methods used in underground mines concentrate on the monitoring of the hazardous gases, fire detection and ventilation. Using advanced instruments and monitoring techniques have significantly reduced the accidents in the modem mines. However despite the advancement of these monitoring facilities, accidents still occur in underground mining annually in the world, and many miners were killed because they were trapped and unable to escape due to blocked of exit access. Described a new development for the emergency evacuation system in underground mines and analyzed the advantages and disadvantages of the system. It is expected that the new system will greatly improve the emergency exit methods and save more lives in the future.展开更多
基金Supported by the Key Projects of Anhui Provincial Scientific and Technological Program （11010401015） the Key Program of National Natural Science Foundation of China （51134012）
文摘During advanced water detection using the transient electromagnetic method, the exploration effect for water-rich area is often poor due to the interference of bolts that are distributed in different positions in working face. Thus, the study on the interference characteristics of bolts in different states has important directive significance for improving the acquisition quality and data processing method in water detection. Based on the analysis of the distribution laws of magnetic field excited by small multi-turn coincident loop in full space of homogeneity, the test on the interference of bolts has been designed in the mine. Through drilling 18 holes around the overlapping coil in the working face, mass data are collected in order with the posi- tion change and the exposed bolt length. The results of comprehensive data analysis show that the transient electromagnetic field is strongly interfered as the distance between the bolt and the center of the coil is less than 3 m, and the interference varies greatly as the distance varies. On the other hand, the field induced by the bolts can be ignored as the distance exceeds 3 m. The findings can help to improve data acquisition and correction during advanced water detection when using the transient electromagnetic method.
基金This work was supported by Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry （2006331）, China Postdoctoral Science Foundation （20070411106） and Open Fund of Key Laboratory of Depositional Mineralization ＆ Sedimentary Mineral, Shandong Province （DMSM200802）.
文摘Well logging technology in coalbed methane （CBM） exploration may develop in two directions： one is the novel well logging methods; the other is the new interpretation methods for the conventional logging data, on which the authors of this paper concentrated mainly. The paper introduced several methods in calculating with well logs such important parameters as porosity, permeability and gas content of CBM reservoir and evaluated their effectiveness. A new method of well logging data interpretation was put forward for coalbed recognition, i.e., the combination of the principal component analysis and the wavelet transform. The authors find that the second principal component （PCA2） contains much more information of coalbed in the coal-bearing series and the reconstruction signal from the detailed wavelet coefficients at level 4 （PCA24） and 5 （PCA25） highlights the signature ofcoalbeds. In terms of the characteristics of CBM reservoir in China, the authors summarized the key points in the application of well logging technique to CBM exploration, and gave a guideline for further related research work.
文摘There are many potential hazards in the underground mining these include fire, explosion, inundation, roof collapse, toxic gases, chemical pollution, etc. Over past centuries, in US alone, more than 100 000 miners lost their life in different accidents. The primary safety methods used in underground mines concentrate on the monitoring of the hazardous gases, fire detection and ventilation. Using advanced instruments and monitoring techniques have significantly reduced the accidents in the modem mines. However despite the advancement of these monitoring facilities, accidents still occur in underground mining annually in the world, and many miners were killed because they were trapped and unable to escape due to blocked of exit access. Described a new development for the emergency evacuation system in underground mines and analyzed the advantages and disadvantages of the system. It is expected that the new system will greatly improve the emergency exit methods and save more lives in the future.
