In order to uncover the intrinsic reasons for spontaneous combustion of sulfide minerals,representative samples were collected from typical metal mines to carry out the mechanical activation experiment.The structures ...In order to uncover the intrinsic reasons for spontaneous combustion of sulfide minerals,representative samples were collected from typical metal mines to carry out the mechanical activation experiment.The structures and heat behaviors of activated samples were characterized by scanning electron microscopy（SEM）,X-ray diffraction（XRD） analysis,and simultaneous thermal analysis（STA）.It is found that the sulfide minerals after mechanical activation show many changes with increased specific surface areas,aggregation phenomenon,decreased diffraction peak intensity,broadened diffraction peak,declined initial temperatures of heat release and self-ignition points.A new theory for explaining the spontaneous combustion of sulfide minerals is put forward：the chemical reaction activity of sulfide minerals is heightened by all kinds of mechanical forces during the mining,and the spontaneous combustion takes place finally under proper environment.展开更多
Mineral consumption is increasing rapidly as more consumers enter the market for minerals and as the global standard of living increases. As a result, underground mining continues to progress to deeper levels in order...Mineral consumption is increasing rapidly as more consumers enter the market for minerals and as the global standard of living increases. As a result, underground mining continues to progress to deeper levels in order to tackle the mineral supply crisis in the 21 st century. However, deep mining occurs in a very technical and challenging environment, in which significant innovative solutions and best practice are required and additional safety standards must be implemented in order to overcome the challenges and reap huge eco- nomic gains. These challenges include the catastrophic events that are often met in deep mining engineering： rockbursts, gas outbursts, high in situ and redistributed stresses, large deformation, squeezing and creeping rocks, and high temperature. This review paper presents the current global status of deep mining and high-lights some of the newest technological achievements and opportunities associated with rock mechanics and geotechnical engineering in deep mining. Of the various technical achievements, unmanned workingfaces and unmanned mines based on fully automated mining and mineral extraction processes have become important fields in the 21 st century.展开更多
We surveyed all known wintering areas of the Black-necked Crane (Grus nigricollis) in Zhigatse Prefecture of the Tibet Autonomous Region during three winters.Our surveys confirm that Zhigatse Prefecture is the most im...We surveyed all known wintering areas of the Black-necked Crane (Grus nigricollis) in Zhigatse Prefecture of the Tibet Autonomous Region during three winters.Our surveys confirm that Zhigatse Prefecture is the most important wintering area for the species,accounting in some years for as much as 39％ of the estimated world population.Counts ranged from a high of 4240 cranes in January 2007 to a low of 2636 in February 2009.Chick recruitment (chicks/100 cranes) ranged from 8.2 (January 2010) to 11.3 (January 2007).The highest concentration of cranes during all three surveys occurred on the 60 km stretch of the Yarlung Tsangpo (River) between Lhaze and Phuntsoling.To evaluate potential impacts of the Xietongmen Copper Mine,we monitored wintering crane numbers prior to mine installation in an intensive study area located between the Shab Chu Valley and the city of Zhigatse.Our surveys recorded on average 820 ± 83 cranes (SE; n =8) in this area.With the installation of the mine at a location ～50 km west of Zhigatse,increased traffic and development on the north side of the Yarlung River will likely result in a shift in crane distribution away from the north side,to nearby suitable habitats.Based on our survey results,we recommend three areas hosting high numbers of cranes in the vicinity of the mine be added to the Yarlung Tsangpo Middle Reaches Black- necked Crane Nature Reserve.These areas are Nierixiong and Jiaqingze Villages in Nierixiong Xiang and the Shab Chu Valley.展开更多
The coincidence of relevant factors, e.g. oxygen absorption quantity, weight increment, water soluble iron ions and sulfate ion of sulfide ore samples in the oxidation process, was tested through experiment. Based on ...The coincidence of relevant factors, e.g. oxygen absorption quantity, weight increment, water soluble iron ions and sulfate ion of sulfide ore samples in the oxidation process, was tested through experiment. Based on a large number of tests for a group sample of sulfide ores from a mine, some important conclusions were obtained. The results obtained by the investigation indicate that there is no general interpretation relative to the oxygen absorption and the formation products of sulfate ion and water soluble iron ions during the oxidation process of sulfide ores at ambient temperature. However, the weight increment of the sulfide ore samples in the oxidation process at ambient temperature has a linear relationship with the auantitv of oxvaen absorption.展开更多
The basic idea of intrinsically safe circuit and the discharge spark in the Buck converter in the explosive at- mospheres were introduced. The Buck converter is the main topological structure of the switch type of int...The basic idea of intrinsically safe circuit and the discharge spark in the Buck converter in the explosive at- mospheres were introduced. The Buck converter is the main topological structure of the switch type of intrinsically safe circuit, which has two working modes: continuous inductive current (CCM — continuous conduction mode) and dis- crete inductance current (DCM — discontinuous conduction mode). The operating state of the continuous inductive current mode is analyzed in detail and the energy of discharge spark in various operating modes is discussed. The total energy will decrease with the increase of switch frequency, in a switching cycle; the discharge spark energy has a maxi- mum and a minimum value. Therefore, the Buck converter has smaller discharge spark energy than the linear power circuit and the switch type of intrinsically safe circuit can enhance the output power and the conversion efficiency of the intrinsically safe power.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
Air leakage velocity in intake goaf and distribution of air leakage in mining area are determined by Instantaneous and steady liberation of tracer gas SF6. Gas concentration and temperature in gob are measured and thr...Air leakage velocity in intake goaf and distribution of air leakage in mining area are determined by Instantaneous and steady liberation of tracer gas SF6. Gas concentration and temperature in gob are measured and three oxidation areas in goaf are determined. According to oxidation experiment of coal and in-site measurements, the gases of carbon monoxide and dioxide can be produced laraely by coal and oxygen combination at ambient temperature and the temperature of coai and rock In goaf con rise 10℃ due to heat produced by coai and oxygen combination.There is a great risk of spontaneous combustion in neighboring oId gob because of air leakage for pillar mining.展开更多
This paper highlights the role of automation technologies for improving the safety, productivity, and environmental sustainability of underground coal mining processes. This is accomplished by reviewing the impact tha...This paper highlights the role of automation technologies for improving the safety, productivity, and environmental sustainability of underground coal mining processes. This is accomplished by reviewing the impact that the introduction of automation technology has made through the longwall shearer automation research program of Longwall Automation Steering Committee(LASC). This result has been achieved through close integration of sensing, processing, and control technologies into the longwall mining process. Key to the success of the automation solution has been the development of new sensing methods to accurately measure the location of longwall equipment and the spatial configuration of coal seam geology. The relevance of system interoperability and open communications standards for facilitating effective automation is also discussed. Importantly, the insights gained through the longwall automation development process are now leading to new technology transfer activity to benefit other underground mining processes.展开更多
To detect the DoS in networks by applying association rules mining techniques, we propose that association rules and frequent itemsets can be employed to find DoS pattern in packet streams which describe traffic and u...To detect the DoS in networks by applying association rules mining techniques, we propose that association rules and frequent itemsets can be employed to find DoS pattern in packet streams which describe traffic and user behaviors. The method extracts information from the log analysis of submitted packets using the algorithm which depends on the definition of the intrusion. Large itemsets were extracted to represent the super facts to build the association analysis for the intrusion. Network data files were analysed for experiments. The analysis and experimental results are encouraging with better performance as packet frequency number increases.展开更多
Mining resources are offered by the natural milieu and liable to exploitation. Raw materials extracted are essential for jewellery and economy. But in most cases, the environmental impact assessment is disappointing. ...Mining resources are offered by the natural milieu and liable to exploitation. Raw materials extracted are essential for jewellery and economy. But in most cases, the environmental impact assessment is disappointing. In this study conducted at Betare Oya, mining residues are directly disposed in the immediate environment without passing through the tailing ponds for treatment, despite environmental laws and standards. Soluble components of matter are slowly dissolved, drained by meteoric water and flowed into tail bay vicinity. Soil and mining residues were sampled in Mari, Mbigala, Mboufa and Bedobo, respectively, four sub-watershed of Lom, the main river of the region. Concentration of nine MTE （metallic trace elements）： As, Cd, Cr, Cu, Co, Ni, Pb, Zn and Hg were determined by ICP-MS （inductively coupled plasma-mass spectrometry）. Highest concentrations of trace and toxic metals in soil and mining residues are： Cr （210 mg·kg-1） 〉 Zn （136 mg·kg-1） 〉 Ni （64 mg·kg-1） 〉 As （34 mg·kg-1） 〉 Cu （30 mg·kg-1） 〉 Pb （25 mg·kg-1） 〉 Co （17 mg·kg-1） 〉 Cd （0.5 mg·kg-1） 〉 Hg （0.1 mg·kg-l）, respectively. These results let assume that it is a risk of environmental pollution and poisoning relative to these elements around Betare Oya opencast mining area, with impact on human health.展开更多
Flow field in multilayer gob area, which formed in small hiden-depth, multi-coal layer groups, close distance, hard coal layer, and hard roof, possesses characteristics such as complex, changeable and unstable. Dynami...Flow field in multilayer gob area, which formed in small hiden-depth, multi-coal layer groups, close distance, hard coal layer, and hard roof, possesses characteristics such as complex, changeable and unstable. Dynamic balance theory of local flow field in multilayer gob area was built based on the realistic requirement that the serious threat on current mining coal layer by large-scale spontaneous combustion fire on close spontaneous combustion coal layer group of Datong Coal mining area at the ＇di-hard＇ conditions was caused by small coal pit mining. The kernel was in dynamic balance between flow field pressures of working face and local flow field in multilayer gob area was kept by transformation. Corresponding technology and set of devices were developed.展开更多
基金Project(2012J05088) supported by the Natural Science Foundation of Fujian Province,ChinaProject(022409) supported by the School Talent Foundation of Fuzhou University,China
文摘In order to uncover the intrinsic reasons for spontaneous combustion of sulfide minerals,representative samples were collected from typical metal mines to carry out the mechanical activation experiment.The structures and heat behaviors of activated samples were characterized by scanning electron microscopy（SEM）,X-ray diffraction（XRD） analysis,and simultaneous thermal analysis（STA）.It is found that the sulfide minerals after mechanical activation show many changes with increased specific surface areas,aggregation phenomenon,decreased diffraction peak intensity,broadened diffraction peak,declined initial temperatures of heat release and self-ignition points.A new theory for explaining the spontaneous combustion of sulfide minerals is put forward：the chemical reaction activity of sulfide minerals is heightened by all kinds of mechanical forces during the mining,and the spontaneous combustion takes place finally under proper environment.
文摘Mineral consumption is increasing rapidly as more consumers enter the market for minerals and as the global standard of living increases. As a result, underground mining continues to progress to deeper levels in order to tackle the mineral supply crisis in the 21 st century. However, deep mining occurs in a very technical and challenging environment, in which significant innovative solutions and best practice are required and additional safety standards must be implemented in order to overcome the challenges and reap huge eco- nomic gains. These challenges include the catastrophic events that are often met in deep mining engineering： rockbursts, gas outbursts, high in situ and redistributed stresses, large deformation, squeezing and creeping rocks, and high temperature. This review paper presents the current global status of deep mining and high-lights some of the newest technological achievements and opportunities associated with rock mechanics and geotechnical engineering in deep mining. Of the various technical achievements, unmanned workingfaces and unmanned mines based on fully automated mining and mineral extraction processes have become important fields in the 21 st century.
文摘We surveyed all known wintering areas of the Black-necked Crane (Grus nigricollis) in Zhigatse Prefecture of the Tibet Autonomous Region during three winters.Our surveys confirm that Zhigatse Prefecture is the most important wintering area for the species,accounting in some years for as much as 39％ of the estimated world population.Counts ranged from a high of 4240 cranes in January 2007 to a low of 2636 in February 2009.Chick recruitment (chicks/100 cranes) ranged from 8.2 (January 2010) to 11.3 (January 2007).The highest concentration of cranes during all three surveys occurred on the 60 km stretch of the Yarlung Tsangpo (River) between Lhaze and Phuntsoling.To evaluate potential impacts of the Xietongmen Copper Mine,we monitored wintering crane numbers prior to mine installation in an intensive study area located between the Shab Chu Valley and the city of Zhigatse.Our surveys recorded on average 820 ± 83 cranes (SE; n =8) in this area.With the installation of the mine at a location ～50 km west of Zhigatse,increased traffic and development on the north side of the Yarlung River will likely result in a shift in crane distribution away from the north side,to nearby suitable habitats.Based on our survey results,we recommend three areas hosting high numbers of cranes in the vicinity of the mine be added to the Yarlung Tsangpo Middle Reaches Black- necked Crane Nature Reserve.These areas are Nierixiong and Jiaqingze Villages in Nierixiong Xiang and the Shab Chu Valley.
文摘The coincidence of relevant factors, e.g. oxygen absorption quantity, weight increment, water soluble iron ions and sulfate ion of sulfide ore samples in the oxidation process, was tested through experiment. Based on a large number of tests for a group sample of sulfide ores from a mine, some important conclusions were obtained. The results obtained by the investigation indicate that there is no general interpretation relative to the oxygen absorption and the formation products of sulfate ion and water soluble iron ions during the oxidation process of sulfide ores at ambient temperature. However, the weight increment of the sulfide ore samples in the oxidation process at ambient temperature has a linear relationship with the auantitv of oxvaen absorption.
文摘The basic idea of intrinsically safe circuit and the discharge spark in the Buck converter in the explosive at- mospheres were introduced. The Buck converter is the main topological structure of the switch type of intrinsically safe circuit, which has two working modes: continuous inductive current (CCM — continuous conduction mode) and dis- crete inductance current (DCM — discontinuous conduction mode). The operating state of the continuous inductive current mode is analyzed in detail and the energy of discharge spark in various operating modes is discussed. The total energy will decrease with the increase of switch frequency, in a switching cycle; the discharge spark energy has a maxi- mum and a minimum value. Therefore, the Buck converter has smaller discharge spark energy than the linear power circuit and the switch type of intrinsically safe circuit can enhance the output power and the conversion efficiency of the intrinsically safe power.
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.
文摘Air leakage velocity in intake goaf and distribution of air leakage in mining area are determined by Instantaneous and steady liberation of tracer gas SF6. Gas concentration and temperature in gob are measured and three oxidation areas in goaf are determined. According to oxidation experiment of coal and in-site measurements, the gases of carbon monoxide and dioxide can be produced laraely by coal and oxygen combination at ambient temperature and the temperature of coai and rock In goaf con rise 10℃ due to heat produced by coai and oxygen combination.There is a great risk of spontaneous combustion in neighboring oId gob because of air leakage for pillar mining.
文摘This paper highlights the role of automation technologies for improving the safety, productivity, and environmental sustainability of underground coal mining processes. This is accomplished by reviewing the impact that the introduction of automation technology has made through the longwall shearer automation research program of Longwall Automation Steering Committee(LASC). This result has been achieved through close integration of sensing, processing, and control technologies into the longwall mining process. Key to the success of the automation solution has been the development of new sensing methods to accurately measure the location of longwall equipment and the spatial configuration of coal seam geology. The relevance of system interoperability and open communications standards for facilitating effective automation is also discussed. Importantly, the insights gained through the longwall automation development process are now leading to new technology transfer activity to benefit other underground mining processes.
文摘To detect the DoS in networks by applying association rules mining techniques, we propose that association rules and frequent itemsets can be employed to find DoS pattern in packet streams which describe traffic and user behaviors. The method extracts information from the log analysis of submitted packets using the algorithm which depends on the definition of the intrusion. Large itemsets were extracted to represent the super facts to build the association analysis for the intrusion. Network data files were analysed for experiments. The analysis and experimental results are encouraging with better performance as packet frequency number increases.
文摘Mining resources are offered by the natural milieu and liable to exploitation. Raw materials extracted are essential for jewellery and economy. But in most cases, the environmental impact assessment is disappointing. In this study conducted at Betare Oya, mining residues are directly disposed in the immediate environment without passing through the tailing ponds for treatment, despite environmental laws and standards. Soluble components of matter are slowly dissolved, drained by meteoric water and flowed into tail bay vicinity. Soil and mining residues were sampled in Mari, Mbigala, Mboufa and Bedobo, respectively, four sub-watershed of Lom, the main river of the region. Concentration of nine MTE （metallic trace elements）： As, Cd, Cr, Cu, Co, Ni, Pb, Zn and Hg were determined by ICP-MS （inductively coupled plasma-mass spectrometry）. Highest concentrations of trace and toxic metals in soil and mining residues are： Cr （210 mg·kg-1） 〉 Zn （136 mg·kg-1） 〉 Ni （64 mg·kg-1） 〉 As （34 mg·kg-1） 〉 Cu （30 mg·kg-1） 〉 Pb （25 mg·kg-1） 〉 Co （17 mg·kg-1） 〉 Cd （0.5 mg·kg-1） 〉 Hg （0.1 mg·kg-l）, respectively. These results let assume that it is a risk of environmental pollution and poisoning relative to these elements around Betare Oya opencast mining area, with impact on human health.
基金Supported by the Key Projects of the National Natural Science Foundation of China （50834002）
文摘Flow field in multilayer gob area, which formed in small hiden-depth, multi-coal layer groups, close distance, hard coal layer, and hard roof, possesses characteristics such as complex, changeable and unstable. Dynamic balance theory of local flow field in multilayer gob area was built based on the realistic requirement that the serious threat on current mining coal layer by large-scale spontaneous combustion fire on close spontaneous combustion coal layer group of Datong Coal mining area at the ＇di-hard＇ conditions was caused by small coal pit mining. The kernel was in dynamic balance between flow field pressures of working face and local flow field in multilayer gob area was kept by transformation. Corresponding technology and set of devices were developed.
