Based on main physical and mechanical properties of deep-sea sediment from C-C poly-metallic nodule mining area in the Pacific Ocean, the best sediment simulant was successfully prepared by mixing bentonite with a cer...Based on main physical and mechanical properties of deep-sea sediment from C-C poly-metallic nodule mining area in the Pacific Ocean, the best sediment simulant was successfully prepared by mixing bentonite with a certain content of water. Compression-shear coupling rheological constitutive model of the sediment simulant was established by endochronic theory and the coupling rheological parameters were obtained by compressive and compression-shear creep tests. A new calculation formula of turning traction force of the tracked mining vehicle was first derived based on the coupling rheological model and consideration of pushing resistance and sinkage of the tracked mining vehicle. Effects of the turning velocity, crawler spacing and contacting length of crawler with deep-sea sediment on the turning traction force were analyzed. Research results can provide theoretical foundation for operation safety and optimal design of the tracked mining vehicle.展开更多
Land subsidence caused by underground coal mining is one of the most prominent environment problems in China. The reclamation of mining subsidence land with Yellow River sediment was considered to be feasible, but its...Land subsidence caused by underground coal mining is one of the most prominent environment problems in China. The reclamation of mining subsidence land with Yellow River sediment was considered to be feasible, but its effectiveness needs to be verified. An integrated reclamation technology with Yellow River sediment was evaluated using a comparison of actual crop production soil profile analysis in Jining City, China. The results indicated that reconstructed soil profile of the reclaimed farmland was less effective in retaining water and in supporting plant growth than that of the unaltered farmland. Some measures are proposed, such as reducing the drainage velocity to allow sedimentation and retention of the clay and silt, changing the techniques of filling the Yellow River sediment and increasing the organic matter content in the soil layers to improve the capacity to retain water in the reclaimed farmland.展开更多
The sinkage of a moving tracked mining vehicle is greatly af fected by the combined compression-shear rheological properties of soft deep-sea sediments. For test purposes, the best sediment simulant is prepared based ...The sinkage of a moving tracked mining vehicle is greatly af fected by the combined compression-shear rheological properties of soft deep-sea sediments. For test purposes, the best sediment simulant is prepared based on soft deep-sea sediment from a C-C poly-metallic nodule mining area in the Pacific Ocean. Compressive creep tests and shear creep tests are combined to obtain compressive and shear rheological parameters to establish a combined compressive-shear rheological constitutive model and a compression-sinkage rheological constitutive model. The combined compression-shear rheological sinkage of the tracked mining vehicle at dif ferent speeds is calculated using the Recur Dyn software with a selfprogrammed subroutine to implement the combined compression-shear rheological constitutive model. The model results are compared with shear rheological sinkage and ordinary sinkage(without consideration of rheological properties). These results show that the combined compression-shear rheological constitutive model must be taken into account when calculating the sinkage of a tracked mining vehicle. The combined compression-shear rheological sinkage decrease with vehicle speed and is the largest among the three types of sinkage. The developed subroutine in the Recur Dyn software can be used to study the performance and structural optimization of moving tracked mining vehicles.展开更多
The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for...The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for this study. The samples were analyzed using the Atomic Absorption Spectrophotometer (AAS). The mean concentrations of Mn (611.37 mg/kg) and Zn (955.86 mg/kg) in the sediments were very high compared to the standard in unpolluted sediments. The enrichment factor (EF) shows that there is an enrichment of Mn at some sites (EF (Mn) > 2). The presence of As, Mn, and Zn is also highlighted by the geo-accumulation index (I-geo) which shows slight pollution in Mn (0 < I-geo (Mn) < 1) on some sites. Moderate pollution for As (1 < I-geo (As) < 2) was determined at the treatment site and high pollution in Zn at some sites in the area (I-geo (Zn) > 3). This study shows that the presence of Zn in the sediments is linked to artisanal gold mining activities. Indeed, Zn is much used for gold recovery. The statistical analysis (PCA) shows, on the one hand, natural mineralization of the sediments and addition of metals linked to anthropic activities corresponding to the erosion of mining discharges. The surface sediments of the Kokumbo mining sites show pollution in As, Mn, and Zn.展开更多
Bottom sediment qualities in Ihetutu minefield were assessed to ascertain the impact of Pb-Zn mining activities on the sediments from streams, rivers and ponds in the area. Levels of Cu, Zn, Fe, Ni, Mn, Pb, Cd and Cr ...Bottom sediment qualities in Ihetutu minefield were assessed to ascertain the impact of Pb-Zn mining activities on the sediments from streams, rivers and ponds in the area. Levels of Cu, Zn, Fe, Ni, Mn, Pb, Cd and Cr and some physico-chemical parameters were measured in bottom sediments taken from four sampling stations (streams/mine pits) within Ihetutu minefield of Ishiagu which receives discharges from mining and human activities, and a control sampling station in Uturu (about 12 km away from study area). The study was conducted in four seasons (Rainy, Late Rainy, Dry, and Late Dry Seasons). Sample digestion was done with a temperature adjustable block digester. Heavy metal analysis was carried out with Flame atomic absorption spectrophotometer (FAAS) while other physico-chemical parameters were determined with standard field and laboratory procedures. Ranges of mean values of results obtained were;pH = 5.81 - 6.44, EC = 269.00 - 1545.00 μS/cm, Cl− = 43.30 - 112.33 mg/kg, alkalinity = 0.70 - 1.25 mg/kg, NO3-?= 5.90 - 7.90 mg/kg, TOC = 0.81 - 1.75 mg/kg, TOM = 1.40 - 3.02 mg/kg, Cu = 4.74 - 50.93 mg/kg, Zn = 26.78 - 57.07 mg/kg, Fe = 1066.19 - 1764.05 mg/kg, Mn = 36.66 - 42.96 mg/kg, Ni = 4.02 - 17.19 mg/kg, Pb = 38.01 - 162.23 mg/kg, Cd = 1.01 - 25.90 mg/kg, and Cr = 1.23 - 1.62 mg/kg. Assessment of heavy metals pollution, using pollution indices revealed that Contamination factor ranged from moderate to very high degree of contamination while Pollution load index also showed a deterioration of bottom sediment qualities. Geoaccummulation index indicated moderate to very high pollution, especially with Cu, Zn, Pb, and Cd in the mine pit, while Enrichment factor indicated high enrichments and inputs from anthropogenic sources especially, the Pb-Zn mining activities. Pollution of the area by heavy metals was in the order of Fe > Pb > Zn > Mn > Cu > Ni > Cd > Cr. Highest positive correlation (r = 0.992) was between Pb and Cu while the highest negative correlation (r = 𕒴.789) was between Ni and Mn. Anal展开更多
With the continuous growth of the population and the continuous reduction of cultivated land,China’s food security is greatly threatened.In addition,China’s coal mining has been mainly underground mining,causing lan...With the continuous growth of the population and the continuous reduction of cultivated land,China’s food security is greatly threatened.In addition,China’s coal mining has been mainly underground mining,causing land subsidence and damaging existing cultivated land.This efect intensifes the contradiction between the growth of the risk population and the reduction of cultivated land.The reclamation of mining subsidence land with Yellow River sediment is often used as an efective way to improve the recovery rate of cultivated land.Shortening the reclamation time and realizing continuous flling are signifcant issues.The work presented in this paper studied the sediment settlement rate and consolidation time by combining theory,feld flling and reclamation tests and numerical simulations.A feld flling test study was carried out in the lowlands of Jibeiwang Village,Qihe County,Shandong Province,China.By calculating the drainage consolidation time,the consolidation factor of 0.015656 m^(2)/d,and the time factor for sediment consolidation of 0.575 were determined.The sediment consolidation time for this test was 9.18 days.The calculation of sediment deposition rate and consolidation time is of great practical signifcance to guide the Yellow River sediment flling,realize continuous flling,and save reclamation time and cost.展开更多
基金Projects(51274251,11502226)supported by the National Natural Science Foundation of China
文摘Based on main physical and mechanical properties of deep-sea sediment from C-C poly-metallic nodule mining area in the Pacific Ocean, the best sediment simulant was successfully prepared by mixing bentonite with a certain content of water. Compression-shear coupling rheological constitutive model of the sediment simulant was established by endochronic theory and the coupling rheological parameters were obtained by compressive and compression-shear creep tests. A new calculation formula of turning traction force of the tracked mining vehicle was first derived based on the coupling rheological model and consideration of pushing resistance and sinkage of the tracked mining vehicle. Effects of the turning velocity, crawler spacing and contacting length of crawler with deep-sea sediment on the turning traction force were analyzed. Research results can provide theoretical foundation for operation safety and optimal design of the tracked mining vehicle.
基金This research was supported by National Key Technology Research and Development Program （2012BAC04B03） during the Twelfth Five-Year Plan Period and National Natural Science Foundation of China （Grant No. 41771542）.
文摘Land subsidence caused by underground coal mining is one of the most prominent environment problems in China. The reclamation of mining subsidence land with Yellow River sediment was considered to be feasible, but its effectiveness needs to be verified. An integrated reclamation technology with Yellow River sediment was evaluated using a comparison of actual crop production soil profile analysis in Jining City, China. The results indicated that reconstructed soil profile of the reclaimed farmland was less effective in retaining water and in supporting plant growth than that of the unaltered farmland. Some measures are proposed, such as reducing the drainage velocity to allow sedimentation and retention of the clay and silt, changing the techniques of filling the Yellow River sediment and increasing the organic matter content in the soil layers to improve the capacity to retain water in the reclaimed farmland.
基金Supported by the National Natural Science Foundation of China(Nos.51274251,11502226)
文摘The sinkage of a moving tracked mining vehicle is greatly af fected by the combined compression-shear rheological properties of soft deep-sea sediments. For test purposes, the best sediment simulant is prepared based on soft deep-sea sediment from a C-C poly-metallic nodule mining area in the Pacific Ocean. Compressive creep tests and shear creep tests are combined to obtain compressive and shear rheological parameters to establish a combined compressive-shear rheological constitutive model and a compression-sinkage rheological constitutive model. The combined compression-shear rheological sinkage of the tracked mining vehicle at dif ferent speeds is calculated using the Recur Dyn software with a selfprogrammed subroutine to implement the combined compression-shear rheological constitutive model. The model results are compared with shear rheological sinkage and ordinary sinkage(without consideration of rheological properties). These results show that the combined compression-shear rheological constitutive model must be taken into account when calculating the sinkage of a tracked mining vehicle. The combined compression-shear rheological sinkage decrease with vehicle speed and is the largest among the three types of sinkage. The developed subroutine in the Recur Dyn software can be used to study the performance and structural optimization of moving tracked mining vehicles.
文摘The main purpose of this study is to characterize the surface sediments of the Kokumbo artisanal gold mining sites in Metallic trace Elements (MTEs). A total of 12 samples of surface water sediments were collected for this study. The samples were analyzed using the Atomic Absorption Spectrophotometer (AAS). The mean concentrations of Mn (611.37 mg/kg) and Zn (955.86 mg/kg) in the sediments were very high compared to the standard in unpolluted sediments. The enrichment factor (EF) shows that there is an enrichment of Mn at some sites (EF (Mn) > 2). The presence of As, Mn, and Zn is also highlighted by the geo-accumulation index (I-geo) which shows slight pollution in Mn (0 < I-geo (Mn) < 1) on some sites. Moderate pollution for As (1 < I-geo (As) < 2) was determined at the treatment site and high pollution in Zn at some sites in the area (I-geo (Zn) > 3). This study shows that the presence of Zn in the sediments is linked to artisanal gold mining activities. Indeed, Zn is much used for gold recovery. The statistical analysis (PCA) shows, on the one hand, natural mineralization of the sediments and addition of metals linked to anthropic activities corresponding to the erosion of mining discharges. The surface sediments of the Kokumbo mining sites show pollution in As, Mn, and Zn.
文摘Bottom sediment qualities in Ihetutu minefield were assessed to ascertain the impact of Pb-Zn mining activities on the sediments from streams, rivers and ponds in the area. Levels of Cu, Zn, Fe, Ni, Mn, Pb, Cd and Cr and some physico-chemical parameters were measured in bottom sediments taken from four sampling stations (streams/mine pits) within Ihetutu minefield of Ishiagu which receives discharges from mining and human activities, and a control sampling station in Uturu (about 12 km away from study area). The study was conducted in four seasons (Rainy, Late Rainy, Dry, and Late Dry Seasons). Sample digestion was done with a temperature adjustable block digester. Heavy metal analysis was carried out with Flame atomic absorption spectrophotometer (FAAS) while other physico-chemical parameters were determined with standard field and laboratory procedures. Ranges of mean values of results obtained were;pH = 5.81 - 6.44, EC = 269.00 - 1545.00 μS/cm, Cl− = 43.30 - 112.33 mg/kg, alkalinity = 0.70 - 1.25 mg/kg, NO3-?= 5.90 - 7.90 mg/kg, TOC = 0.81 - 1.75 mg/kg, TOM = 1.40 - 3.02 mg/kg, Cu = 4.74 - 50.93 mg/kg, Zn = 26.78 - 57.07 mg/kg, Fe = 1066.19 - 1764.05 mg/kg, Mn = 36.66 - 42.96 mg/kg, Ni = 4.02 - 17.19 mg/kg, Pb = 38.01 - 162.23 mg/kg, Cd = 1.01 - 25.90 mg/kg, and Cr = 1.23 - 1.62 mg/kg. Assessment of heavy metals pollution, using pollution indices revealed that Contamination factor ranged from moderate to very high degree of contamination while Pollution load index also showed a deterioration of bottom sediment qualities. Geoaccummulation index indicated moderate to very high pollution, especially with Cu, Zn, Pb, and Cd in the mine pit, while Enrichment factor indicated high enrichments and inputs from anthropogenic sources especially, the Pb-Zn mining activities. Pollution of the area by heavy metals was in the order of Fe > Pb > Zn > Mn > Cu > Ni > Cd > Cr. Highest positive correlation (r = 0.992) was between Pb and Cu while the highest negative correlation (r = 𕒴.789) was between Ni and Mn. Anal
基金This research was funded by Jiangxi Provincial Social Science Foundation“the 14th Five-Year Plan”(2021)regional projects(21DQ44)National Natural Science Foundation of China(41771542)+3 种基金Institutional Research Centers of Jiangxi Provincial of Ecological Civilization Construction(JXST2103)Research Center of Geological Resource Economics and Management(20GL02)Science and Technology Research Project of Jiangxi Provincial Department of Education(GJJ210723)the Doctoral Research Initiation fund of East China University of Technology(DHBK2019184).
文摘With the continuous growth of the population and the continuous reduction of cultivated land,China’s food security is greatly threatened.In addition,China’s coal mining has been mainly underground mining,causing land subsidence and damaging existing cultivated land.This efect intensifes the contradiction between the growth of the risk population and the reduction of cultivated land.The reclamation of mining subsidence land with Yellow River sediment is often used as an efective way to improve the recovery rate of cultivated land.Shortening the reclamation time and realizing continuous flling are signifcant issues.The work presented in this paper studied the sediment settlement rate and consolidation time by combining theory,feld flling and reclamation tests and numerical simulations.A feld flling test study was carried out in the lowlands of Jibeiwang Village,Qihe County,Shandong Province,China.By calculating the drainage consolidation time,the consolidation factor of 0.015656 m^(2)/d,and the time factor for sediment consolidation of 0.575 were determined.The sediment consolidation time for this test was 9.18 days.The calculation of sediment deposition rate and consolidation time is of great practical signifcance to guide the Yellow River sediment flling,realize continuous flling,and save reclamation time and cost.
