To find discriminating features in seismograms for the classification of mine seismic events,signal databases of blasts and microseismic events were established based on manual identification.Criteria including the re...To find discriminating features in seismograms for the classification of mine seismic events,signal databases of blasts and microseismic events were established based on manual identification.Criteria including the repetition of waveforms,tail decreasing,dominant frequency and occurrence time of day were considered in the establishment of the databases.Signals from databases of different types were drawn into a unified coordinate system.It is noticed that the starting-up angles of the two types tend to be concentrated into two different intervals.However,it is difficult to calculate the starting-up angle directly due to the inaccuracy of the P-wave arrival＇s picking.The slope value of the starting-up trend line,which was obtained by linear regression,was proposed to substitute the angle.Two slope values associated with the coordinates of the first peak and the maximum peak were extracted as the characteristic parameters.A statistical model with correct discrimination rate of greater than 97.1% was established by applying the Fisher discriminant analysis.展开更多
We present a super-range seismic observation along the >1300-km-long profile passing through the Yinchuan basin and the Ordos block from the blasting point towards the southeast triggered by a large-(dynamite) scal...We present a super-range seismic observation along the >1300-km-long profile passing through the Yinchuan basin and the Ordos block from the blasting point towards the southeast triggered by a large-(dynamite) scale coal blast in the Ningxia Hui Autonomous Region's Helan Mountain (yielded a profile). The seismic wave information from the uppermost mantle reflecting different depths was obtained by the China continental seismic survey. Pn refracted waves from the uppermost mantle were effectively traced up to 500 km and beyond. The stable dynamic and kinematic characteristics of the Pn wave-group indicate that the uppermost mantle below the Ordos block is a gently changing structure with a weak positive gradient. If Pm1, Pm2 waves are considered as the wave groups from the upper mantle, there may be distinct structural strata in the upper-mantle structures with average velocities of 7.70―7.80 km/s and 8.10―8.20 km/s, respectively. Based on the travel-time curve feature of Pm1, Pm2 waves, there may be a certain layer with a reverse velocity between the M1 and M2 interfaces. The depth range indicated by them is about 110―120 km and 200―220 km. These phenomena basically reflect the structural features of the upper-mantle lithosphere in this region. The information obtained may provide meaningful references for surveying North China craton lithospheric structures, as well as under-standing the shapes and structures of different spherical layers within the upper-mantle.展开更多
The micromorphology and physicochemical properties of hydrophobic blasting dust(HBD)from an iron mine were comprehensively analyzed by laser particle size analysis(LPSA),scanning electron microscopy(SEM),X-ray diffrac...The micromorphology and physicochemical properties of hydrophobic blasting dust(HBD)from an iron mine were comprehensively analyzed by laser particle size analysis(LPSA),scanning electron microscopy(SEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).The results show that the HBD particles can be classified into three types based on their particle size(PS):larger particles(PS>10μm),medium particles(1μm≤PS≤10μm),and nanoparticles(PS<1μm).The cumulative volume of respirable dust(PS≤10μm)was 84.45%.In addition,three shapes of HBD were observed by SEM:prism,flake,and bulk.In particular,the small particles were mostly flaky,with a greater possibility of being inhaled.Furthermore,the body and surface chemical compounds of HBD were determined by XRD and XPS,respectively.Ammonium adipate(C6H16N2O4)was the only organic compound in the body of HBD,but its mass fraction was only 13.4%.However,the content of organic C on the surface of HBD was 85.35%.This study demonstrated that the small-particle size and large amount of organic matter on the surface of HBD are the main reasons for its hydrophobicity,which can provide important guidance for controlling respirable dust in iron mines.展开更多
Frequency and scale of the blasting events are increasing to boost limestone production. Mines areapproaching close to inhabited areas due to growing population and limited availability of land resourceswhich has chal...Frequency and scale of the blasting events are increasing to boost limestone production. Mines areapproaching close to inhabited areas due to growing population and limited availability of land resourceswhich has challenged the management to go for safe blasts with special reference to opencast mining.The study aims to predict the distance covered by the flyrock induced by blasting using artificial neuralnetwork （ANN） and multi-variate regression analysis （MVRA） for better assessment. Blast design andgeotechnical parameters, such as linear charge concentration, burden, stemming length, specific charge,unconfined compressive strength （UCS）, and rock quality designation （RQD）, have been selected as inputparameters and flyrock distance used as output parameter. ANN has been trained using 95 datasets ofexperimental blasts conducted in 4 opencast limestone mines in India. Thirty datasets have been used fortesting and validation of trained neural network. Flyrock distances have been predicted by ANN, MVRA,as well as further calculated using motion analysis of flyrock projectiles and compared with the observeddata. Back propagation neural network （BPNN） has been proven to be a superior predictive tool whencompared with MVRA. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.展开更多
Generally, the Mos hardness of bauxite is 2.5 to 3.5. According to the specific conditions of the Sangaredi bauxite deposit, that is, the rock hardness coefficient is between 3 and 6, and there is a clayey zone in the...Generally, the Mos hardness of bauxite is 2.5 to 3.5. According to the specific conditions of the Sangaredi bauxite deposit, that is, the rock hardness coefficient is between 3 and 6, and there is a clayey zone in the bauxite mining area, it is necessary to carry out blasting work before mining. This article mainly analyzes and optimizes the blasting practice of the Sangaredi open pit bauxite mine. The subject was finally extended to the reduction of nuisances due to blasting, that is to say essentially due to vibrations: this presupposed a study around the vibration data available, and the proposal of methods to limit these vibrations. The bottom conditions of the Sangaredi bauxite ore zone are studied. Bauxite reserves are very rich and the market is huge. The analysis of mine blasting practices, mainly the types of explosives, the selection and analysis of explosives and blasting equipment and choosing the mode of longitudinal blasting, the link of the blasting site of the mining area, further study the optimization of mining blasting practice, the choice of drilling and process to determine reasonable blasting parameters, which improving the drilling method. The experimental results show that this optimization scheme improves efficiency blasting of the bauxite mine but also promotes an increase in production.展开更多
This study explores the key physicochemical factors affecting the hydrophilic characteristics of iron mine blasting dust(BD). The BD is separated into an unwetted part(UWBD, hydrophobic part) and a wetted part(WBD, hy...This study explores the key physicochemical factors affecting the hydrophilic characteristics of iron mine blasting dust(BD). The BD is separated into an unwetted part(UWBD, hydrophobic part) and a wetted part(WBD, hydrophilic part). Its particle size, true density(TD), pore parameters, mineral composition, and surface compounds are comprehensively characterized and compared. The results indicate that a smaller particle size and more developed pore parameters are two key factors responsible for the strong hydrophobicity of the BD. The mineral composition of the BD has no direct effect on its wetting properties;however, it indirectly influences the deposition characteristics of the BD in water by affecting its TD. Unlike coal dust, the surface organic composition of the BD does not affect its wettability and the peak area of C–C/C–H hydrophobic groups in the C 1s X-ray photoelectron spectrum of the UWBD(45.03%) is smaller than that in the C 1s spectrum of the WBD(68.30%). Thus, eleven co-influencing processes of physicochemical properties of the BD on its wettability are summarized. This research sheds light on the key factors affecting the wettability of the BD.展开更多
基金Projects(51374244,11447241)supported by the National Natural Science Foundation of China
文摘To find discriminating features in seismograms for the classification of mine seismic events,signal databases of blasts and microseismic events were established based on manual identification.Criteria including the repetition of waveforms,tail decreasing,dominant frequency and occurrence time of day were considered in the establishment of the databases.Signals from databases of different types were drawn into a unified coordinate system.It is noticed that the starting-up angles of the two types tend to be concentrated into two different intervals.However,it is difficult to calculate the starting-up angle directly due to the inaccuracy of the P-wave arrival＇s picking.The slope value of the starting-up trend line,which was obtained by linear regression,was proposed to substitute the angle.Two slope values associated with the coordinates of the first peak and the maximum peak were extracted as the characteristic parameters.A statistical model with correct discrimination rate of greater than 97.1% was established by applying the Fisher discriminant analysis.
基金Supported by National Natural Science Foundation of China (Grant No. 90814012)National Basic Research Program of China (Grant No. 2004CB428400)Contribution No.: 0801, Geophysical Exploration Center, China Earthquake Administration
文摘We present a super-range seismic observation along the >1300-km-long profile passing through the Yinchuan basin and the Ordos block from the blasting point towards the southeast triggered by a large-(dynamite) scale coal blast in the Ningxia Hui Autonomous Region's Helan Mountain (yielded a profile). The seismic wave information from the uppermost mantle reflecting different depths was obtained by the China continental seismic survey. Pn refracted waves from the uppermost mantle were effectively traced up to 500 km and beyond. The stable dynamic and kinematic characteristics of the Pn wave-group indicate that the uppermost mantle below the Ordos block is a gently changing structure with a weak positive gradient. If Pm1, Pm2 waves are considered as the wave groups from the upper mantle, there may be distinct structural strata in the upper-mantle structures with average velocities of 7.70―7.80 km/s and 8.10―8.20 km/s, respectively. Based on the travel-time curve feature of Pm1, Pm2 waves, there may be a certain layer with a reverse velocity between the M1 and M2 interfaces. The depth range indicated by them is about 110―120 km and 200―220 km. These phenomena basically reflect the structural features of the upper-mantle lithosphere in this region. The information obtained may provide meaningful references for surveying North China craton lithospheric structures, as well as under-standing the shapes and structures of different spherical layers within the upper-mantle.
基金financially supported by the National Key Research and Development Program of China(No.SQ2017YFSF060069)the National Natural Science Foundation of China(No.51574017)
文摘The micromorphology and physicochemical properties of hydrophobic blasting dust(HBD)from an iron mine were comprehensively analyzed by laser particle size analysis(LPSA),scanning electron microscopy(SEM),X-ray diffraction(XRD),and X-ray photoelectron spectroscopy(XPS).The results show that the HBD particles can be classified into three types based on their particle size(PS):larger particles(PS>10μm),medium particles(1μm≤PS≤10μm),and nanoparticles(PS<1μm).The cumulative volume of respirable dust(PS≤10μm)was 84.45%.In addition,three shapes of HBD were observed by SEM:prism,flake,and bulk.In particular,the small particles were mostly flaky,with a greater possibility of being inhaled.Furthermore,the body and surface chemical compounds of HBD were determined by XRD and XPS,respectively.Ammonium adipate(C6H16N2O4)was the only organic compound in the body of HBD,but its mass fraction was only 13.4%.However,the content of organic C on the surface of HBD was 85.35%.This study demonstrated that the small-particle size and large amount of organic matter on the surface of HBD are the main reasons for its hydrophobicity,which can provide important guidance for controlling respirable dust in iron mines.
文摘Frequency and scale of the blasting events are increasing to boost limestone production. Mines areapproaching close to inhabited areas due to growing population and limited availability of land resourceswhich has challenged the management to go for safe blasts with special reference to opencast mining.The study aims to predict the distance covered by the flyrock induced by blasting using artificial neuralnetwork （ANN） and multi-variate regression analysis （MVRA） for better assessment. Blast design andgeotechnical parameters, such as linear charge concentration, burden, stemming length, specific charge,unconfined compressive strength （UCS）, and rock quality designation （RQD）, have been selected as inputparameters and flyrock distance used as output parameter. ANN has been trained using 95 datasets ofexperimental blasts conducted in 4 opencast limestone mines in India. Thirty datasets have been used fortesting and validation of trained neural network. Flyrock distances have been predicted by ANN, MVRA,as well as further calculated using motion analysis of flyrock projectiles and compared with the observeddata. Back propagation neural network （BPNN） has been proven to be a superior predictive tool whencompared with MVRA. 2014 Institute of Rock and Soil Mechanics, Chinese Academy of Sciences. Production and hosting byElsevier B.V. All rights reserved.
文摘Generally, the Mos hardness of bauxite is 2.5 to 3.5. According to the specific conditions of the Sangaredi bauxite deposit, that is, the rock hardness coefficient is between 3 and 6, and there is a clayey zone in the bauxite mining area, it is necessary to carry out blasting work before mining. This article mainly analyzes and optimizes the blasting practice of the Sangaredi open pit bauxite mine. The subject was finally extended to the reduction of nuisances due to blasting, that is to say essentially due to vibrations: this presupposed a study around the vibration data available, and the proposal of methods to limit these vibrations. The bottom conditions of the Sangaredi bauxite ore zone are studied. Bauxite reserves are very rich and the market is huge. The analysis of mine blasting practices, mainly the types of explosives, the selection and analysis of explosives and blasting equipment and choosing the mode of longitudinal blasting, the link of the blasting site of the mining area, further study the optimization of mining blasting practice, the choice of drilling and process to determine reasonable blasting parameters, which improving the drilling method. The experimental results show that this optimization scheme improves efficiency blasting of the bauxite mine but also promotes an increase in production.
基金financially supported by the National Key Research and Development Program of China (No. 2017YFC0805204)the National Natural Science Foundation of China (Nos. 51874015 and 51504017)
文摘This study explores the key physicochemical factors affecting the hydrophilic characteristics of iron mine blasting dust(BD). The BD is separated into an unwetted part(UWBD, hydrophobic part) and a wetted part(WBD, hydrophilic part). Its particle size, true density(TD), pore parameters, mineral composition, and surface compounds are comprehensively characterized and compared. The results indicate that a smaller particle size and more developed pore parameters are two key factors responsible for the strong hydrophobicity of the BD. The mineral composition of the BD has no direct effect on its wetting properties;however, it indirectly influences the deposition characteristics of the BD in water by affecting its TD. Unlike coal dust, the surface organic composition of the BD does not affect its wettability and the peak area of C–C/C–H hydrophobic groups in the C 1s X-ray photoelectron spectrum of the UWBD(45.03%) is smaller than that in the C 1s spectrum of the WBD(68.30%). Thus, eleven co-influencing processes of physicochemical properties of the BD on its wettability are summarized. This research sheds light on the key factors affecting the wettability of the BD.
