ln-situ experiments were conducted to investigate the mechanical properties of the soil-rock mixture in the internal dump of the Shengli #1 Surface Coal Mine, China. Based on the experimental results, this study used ...ln-situ experiments were conducted to investigate the mechanical properties of the soil-rock mixture in the internal dump of the Shengli #1 Surface Coal Mine, China. Based on the experimental results, this study used comparative analysis and found that the shear strength of the soil-rock mixture in the dump was greater than the residual shear strength of the original rock. The results showed that the material presented in the dump as large blocks was the main factor affecting the strength of the soil-rock mixture, Numerical simulation was carried out for the analyses of three factors： different combinations of shear failure, rolling failure along with different large-block radius ratios, and mixture densities. The results illustrated that the cohesion and angle of internal friction of the soil-rock mixture are 12 kPa and 32.26°. However, in some cases the bench angle in the dump was controlled by a coupling relationship of rocks in the material. Finally, the stability of a soil slope showed a linear relationship with the large-block radius ratio and the bulk density.展开更多
According to the characteristics of opencast coal resources and dragline technology system application in China,the structure and shifting step of transport passage are optimized in this paper.Typical coal transport p...According to the characteristics of opencast coal resources and dragline technology system application in China,the structure and shifting step of transport passage are optimized in this paper.Typical coal transport passage is analyzed in aspects such as the internal dump occupation,dragline operation efficiency,coal transport distance,upper stripping distance and shifting quantities.The middle passage should be given priority in thick overburden open pit mine because the dragline system is only responsible for part stripping task.According to characteristics of middle passage,the transport passage is divided into parallel climbing,vertical climbing and horizontal transport.In addition,the transport passage structure optimization model and shifting distance optimization model are established in this paper.The case study in Heidaigou open pit mine shows that,the parallel climbing height is accounted for about 60%of the total height,and reasonable shifting distances of the first mining area and the second mining area are 240 and 320 m.Sensitivity analysis shows that,the total passage height has important influence on the shifting step,so it is with the stripping height and passage construction cost to the passage structure.展开更多
Transportation accounts for 80% of open-cut coal mine carbon emissions. With regard to the energy con- sumption and carbon emissions of transportation within an open-cut mine, this paper systematically compared the wo...Transportation accounts for 80% of open-cut coal mine carbon emissions. With regard to the energy con- sumption and carbon emissions of transportation within an open-cut mine, this paper systematically compared the work and energy consumption of a truck and belt conveyor on a theoretical basis, and con- structed a model to calculate the energy consumption of open-cut mine transportation. Life cycle carbon emission factors and power consumption calculation model were established through a Process Analysis- Life Cycle Analysis （PA-LCA）. The following results were obtained： （1） the energy consumption of truck transportation was four to twelve times higher than that of the belt conveyor; （2） the C02 emissions from truck transportation were three to ten times higher than those of the belt conveyor; （3） with the increase in the slope angle for transportation, the ratio of truck to belt conveyor for both energy consumption and carbon emissions gradually decreased; （4） based on 2013 prices in China, the energy cost of transportation using a belt conveyor in open-cut coal mines could save 0.6-2.4 Yuan/（t kin） compared to truck transportation.展开更多
In order to study the stability control mechanism of a concave slope with circular landslide, and remove the influence of differences in shape on slope stability, the limit analysis method of a simplified Bishop metho...In order to study the stability control mechanism of a concave slope with circular landslide, and remove the influence of differences in shape on slope stability, the limit analysis method of a simplified Bishop method was employed. The sliding body was divided into strips in a three-dimensional model, and the lateral earth pressure was put into mechanical analysis and the three-dimensional stability analysis methods applicable for circular sliding in concave slope were deduced. Based on geometric structure and the geological parameters of a concave slope, the influence rule of curvature radius and the top and bottom arch height on the concave slope stability were analyzed. The results show that the stability coefficient decreases after growth, first in the transition stage of slope shape from flat to concave, and it has been confirmed that there is a best size to make the slope stability factor reach a maximum. By contrast with average slope, the stability of a concave slope features a smaller range of ascension with slope height increase, which indicates that the enhancing effect of a concave slope is apparent only with lower slope heights.展开更多
The distribution characteristics of methyl mercury in Rana chensinensis and water,sediment and soil in gold-mining areas of the upper reaches of the Songhua River,China were studied by field sampling and laboratory te...The distribution characteristics of methyl mercury in Rana chensinensis and water,sediment and soil in gold-mining areas of the upper reaches of the Songhua River,China were studied by field sampling and laboratory testing.The results show that the methyl mercury contents in water,sediment and soil in gold-mining areas are much higher than those in the control site,indicating that gold-mining activities intensify the methyl mercury pollution in the study area.Methyl mercury contents are in a descending order of sediment > soil > water in the environment,and in a descending order of brain > viscera > muscle > skin in Rana chensinensis.There are significant correlation between methyl mercury contents in Rana chensinensis and those in water and sediment.In particular,the methyl mercury content in the skin of Rana chensinensis is positively correlated with those in water and sediment in spring.Therefore,skin is one of main intake pathways for methyl mercury due to its high permeability.展开更多
In order to enhance coal recovery ratio of open pit coal mines, a new extraction method called zonal mining system for residual coal around the end-walls is presented. The mining system can improve economic benefits b...In order to enhance coal recovery ratio of open pit coal mines, a new extraction method called zonal mining system for residual coal around the end-walls is presented. The mining system can improve economic benefits by exploiting haulage and ventilation roadways from the exposed position of coal seams by uti- lizing the existing transportation systems. Moreover, the main mining parameters have also been dis- cussed. The outcome shows that the load on coal seam roof is about 0.307 MPa and the drop step of the coal seam roof about 20.3 m when the thickness of cover and average volume weight are about 120 m and 0.023 MN/m~ respectively. With the increase of mining height and width, the coal recovery ratio can be improved. However, when recovery ratio is more than 0.85, the average stress on the coal pillar will increase tempestuously, so the recovery ratio should also be controlled to make the coal seam roof safe. Based on the numerical simulation results, it is concluded that the ratio of coal pillar width to height should be more than 1.0 to make sure the coal pillars are steady, and there are only minor dis- placements on the end-walls.展开更多
Leaving ditches between adjacent mining areas can effectively reduce re-stripping in the latter mining area and simultaneously lead to an increment in internal dumping costs in the former mining area. This paper estab...Leaving ditches between adjacent mining areas can effectively reduce re-stripping in the latter mining area and simultaneously lead to an increment in internal dumping costs in the former mining area. This paper establishes calculation models for these two marginal costs. The optimizing model for slope cover height can be determined by including marginal cost models in the objective function. The paper has two main contributions:(a) it fully considers redistribution of dumping space in the model;(b) it introduces price fluctuations and cash discounts in the model. We use the typical open-pit mine as an example to test and prove the model. We conclude that a completely covered slope is reasonable in Haerwusu open pit mine; in addition to an increasing price index, the slope cover height can be reduced; and that price changes are one of the most important influencing factors of slope cover height optimization in an open-pit mine.展开更多
基金financially supported by the Key Program of the National Natural Science Foundation of China(No.51574222)National Natural Science Foundation of China(No.51034005)+1 种基金Program for New Century Excellent Talents in University of China(No.NCET-13-1022)National Key Research and Development Plan of China(No.2016YFC0501103)
文摘ln-situ experiments were conducted to investigate the mechanical properties of the soil-rock mixture in the internal dump of the Shengli #1 Surface Coal Mine, China. Based on the experimental results, this study used comparative analysis and found that the shear strength of the soil-rock mixture in the dump was greater than the residual shear strength of the original rock. The results showed that the material presented in the dump as large blocks was the main factor affecting the strength of the soil-rock mixture, Numerical simulation was carried out for the analyses of three factors： different combinations of shear failure, rolling failure along with different large-block radius ratios, and mixture densities. The results illustrated that the cohesion and angle of internal friction of the soil-rock mixture are 12 kPa and 32.26°. However, in some cases the bench angle in the dump was controlled by a coupling relationship of rocks in the material. Finally, the stability of a soil slope showed a linear relationship with the large-block radius ratio and the bulk density.
基金Financial support from the National High-Tech Research and Development Program of China(No.2012AA062004)the National Natural Science Foundation of China(No.51034005)
文摘According to the characteristics of opencast coal resources and dragline technology system application in China,the structure and shifting step of transport passage are optimized in this paper.Typical coal transport passage is analyzed in aspects such as the internal dump occupation,dragline operation efficiency,coal transport distance,upper stripping distance and shifting quantities.The middle passage should be given priority in thick overburden open pit mine because the dragline system is only responsible for part stripping task.According to characteristics of middle passage,the transport passage is divided into parallel climbing,vertical climbing and horizontal transport.In addition,the transport passage structure optimization model and shifting distance optimization model are established in this paper.The case study in Heidaigou open pit mine shows that,the parallel climbing height is accounted for about 60%of the total height,and reasonable shifting distances of the first mining area and the second mining area are 240 and 320 m.Sensitivity analysis shows that,the total passage height has important influence on the shifting step,so it is with the stripping height and passage construction cost to the passage structure.
基金supported by the key project of the National Natural Science Foundation of China(No.51034005)the Research Fund for the Doctoral Program of Higher Education(the Specialized Research Fund for the Doctoral Program of Higher Education of China)(No.20100095110019)+1 种基金the National‘‘Twelfth Five-Year’’Plan for Science&Technology Support(No.2014BAC14B00)the National High Technology Research and Development Program of China(No.2012AA062004)
文摘Transportation accounts for 80% of open-cut coal mine carbon emissions. With regard to the energy con- sumption and carbon emissions of transportation within an open-cut mine, this paper systematically compared the work and energy consumption of a truck and belt conveyor on a theoretical basis, and con- structed a model to calculate the energy consumption of open-cut mine transportation. Life cycle carbon emission factors and power consumption calculation model were established through a Process Analysis- Life Cycle Analysis （PA-LCA）. The following results were obtained： （1） the energy consumption of truck transportation was four to twelve times higher than that of the belt conveyor; （2） the C02 emissions from truck transportation were three to ten times higher than those of the belt conveyor; （3） with the increase in the slope angle for transportation, the ratio of truck to belt conveyor for both energy consumption and carbon emissions gradually decreased; （4） based on 2013 prices in China, the energy cost of transportation using a belt conveyor in open-cut coal mines could save 0.6-2.4 Yuan/（t kin） compared to truck transportation.
基金financially supported by the China Postdoctoral Science Foundation(No.2015M580491)the National Natural Science Foundation of China(No.51404262)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20140213)the National High Technology Research and Development Program of China(No.2012AA062004)
文摘In order to study the stability control mechanism of a concave slope with circular landslide, and remove the influence of differences in shape on slope stability, the limit analysis method of a simplified Bishop method was employed. The sliding body was divided into strips in a three-dimensional model, and the lateral earth pressure was put into mechanical analysis and the three-dimensional stability analysis methods applicable for circular sliding in concave slope were deduced. Based on geometric structure and the geological parameters of a concave slope, the influence rule of curvature radius and the top and bottom arch height on the concave slope stability were analyzed. The results show that the stability coefficient decreases after growth, first in the transition stage of slope shape from flat to concave, and it has been confirmed that there is a best size to make the slope stability factor reach a maximum. By contrast with average slope, the stability of a concave slope features a smaller range of ascension with slope height increase, which indicates that the enhancing effect of a concave slope is apparent only with lower slope heights.
基金Under the auspices of National Natural Science Foundation of China (No. 40673059)Testing Foundation of Northeast Normal University
文摘The distribution characteristics of methyl mercury in Rana chensinensis and water,sediment and soil in gold-mining areas of the upper reaches of the Songhua River,China were studied by field sampling and laboratory testing.The results show that the methyl mercury contents in water,sediment and soil in gold-mining areas are much higher than those in the control site,indicating that gold-mining activities intensify the methyl mercury pollution in the study area.Methyl mercury contents are in a descending order of sediment > soil > water in the environment,and in a descending order of brain > viscera > muscle > skin in Rana chensinensis.There are significant correlation between methyl mercury contents in Rana chensinensis and those in water and sediment.In particular,the methyl mercury content in the skin of Rana chensinensis is positively correlated with those in water and sediment in spring.Therefore,skin is one of main intake pathways for methyl mercury due to its high permeability.
文摘In order to enhance coal recovery ratio of open pit coal mines, a new extraction method called zonal mining system for residual coal around the end-walls is presented. The mining system can improve economic benefits by exploiting haulage and ventilation roadways from the exposed position of coal seams by uti- lizing the existing transportation systems. Moreover, the main mining parameters have also been dis- cussed. The outcome shows that the load on coal seam roof is about 0.307 MPa and the drop step of the coal seam roof about 20.3 m when the thickness of cover and average volume weight are about 120 m and 0.023 MN/m~ respectively. With the increase of mining height and width, the coal recovery ratio can be improved. However, when recovery ratio is more than 0.85, the average stress on the coal pillar will increase tempestuously, so the recovery ratio should also be controlled to make the coal seam roof safe. Based on the numerical simulation results, it is concluded that the ratio of coal pillar width to height should be more than 1.0 to make sure the coal pillars are steady, and there are only minor dis- placements on the end-walls.
基金the key project of the National Natural Science Foundation of China (No. 51034005)the Research Fund for the Doctoral Program of Higher Education of China(No.20100095110019)+1 种基金the National‘‘Twelfth Five-Year’’Plan for Science and Technology Support of China(No.2014BAC14B00)the National High Technology Research and Development Program of China(No.2012AA062004)
文摘Leaving ditches between adjacent mining areas can effectively reduce re-stripping in the latter mining area and simultaneously lead to an increment in internal dumping costs in the former mining area. This paper establishes calculation models for these two marginal costs. The optimizing model for slope cover height can be determined by including marginal cost models in the objective function. The paper has two main contributions:(a) it fully considers redistribution of dumping space in the model;(b) it introduces price fluctuations and cash discounts in the model. We use the typical open-pit mine as an example to test and prove the model. We conclude that a completely covered slope is reasonable in Haerwusu open pit mine; in addition to an increasing price index, the slope cover height can be reduced; and that price changes are one of the most important influencing factors of slope cover height optimization in an open-pit mine.
