It is of great significance to analyze the chemical indexes of mine water and develop a rapid identification system of water source, which can quickly and accurately distinguish the causes of water inrush and identify...It is of great significance to analyze the chemical indexes of mine water and develop a rapid identification system of water source, which can quickly and accurately distinguish the causes of water inrush and identify the source of water inrush, so as to reduce casualties and economic losses and prevent and control water inrush disasters. Taking Ca<sup>2+</sup>, Mg<sup>2+</sup>, Na<sup>+</sup> + K<sup>+</sup>, , , Cl<sup>-</sup>, pH value and TDS as discriminant indexes, the principal component analysis method was used to reduce the dimension of data, and the identification model of mine water inrush source based on PCA-BP neural network was established. 96 sets of data of different aquifers in Panxie mining area were selected for prediction analysis, and 20 sets of randomly selected data were tested, with an accuracy rate of 95%. The model can effectively reduce data redundancy, has a high recognition rate, and can accurately and quickly identify the water source of mine water inrush.展开更多
The study investigates the hydrogeochemical characteristics of some towns in the Abakaliki Basin, comprising, Ishiagu, Aka Eze, Amaseri, Afikpo and Okposi communities, with the aim of sourcing for portable water in th...The study investigates the hydrogeochemical characteristics of some towns in the Abakaliki Basin, comprising, Ishiagu, Aka Eze, Amaseri, Afikpo and Okposi communities, with the aim of sourcing for portable water in the area. The basin is underlain by Albian sediments, essentially shales, in the lowlands, which were affected by low-grade metamorphism that had produced slates. The highlands comprise basic intrusives from episodes of magmatism and metallic ore mineralisation. Injection of brines into the aquifer system and low, seasonal aquifer recharge from rainfall results in poor water quality in the area. The study analyzes the geochemical distribution in water sources in the area and identifies sources of pollutants to guide the better choice of portable water. Results of hydrogeochemical analysis of both surface and groundwater from the communities were compared with World Health Organization to identify portable water locations in the area. While the salt lake at Okposi is the main source of brine intrusion in the study area, the Pb/Zn mine at Ishiagu is the main source of mine-water pollution in the study area. Most chemical parameters, (especially Cl<sup>-</sup>, Na<sup>+</sup>, Ca<sup>2+</sup>, Mg<sup>2+</sup>, SO<sub>4</sub><sup>2-</sup>, HCO<sub>3</sub><sup>-</sup>) maintain high concentrations within the salt lake area, with the values declining away from the salt lake. The main anthropogenic source of pollution in the area, especially at Ishiagu, is the indiscriminate surface mining of lead-zinc without proposer waste management practices. Possible sourcing for portable water in the study area includes a deep borehole at Ishiagu, away from lead-zinc intrusives. At the Okposi axis, searching for portable water in boreholes should target shallower aquifers that do not communicate with the deeper-seated brine zones, likewise targeting zones farther away from these brine-invaded areas. A controlled pumping rate could potentially ensure that the cone of depression was not low enough to reach the brine zone at depth. In addition, desalination could also potentially render the salt water drinkable if properly handled to eliminate the high concentration of salts in the water to the level of acceptable limit by the WHO. Based on the study, the best area to target for portable water in the study area is Afikpo, with most geochemical elements naturally occurring within WHO’s standard concentration while portable water could be harnessed in areas further away from mining sites, especially at deep groundwater.展开更多
As a new technical means that can detect abnormal signs of water inrush in advance and give an early warning,the automatic monitoring and early warning of water inrush in mines has been widely valued in recent years.D...As a new technical means that can detect abnormal signs of water inrush in advance and give an early warning,the automatic monitoring and early warning of water inrush in mines has been widely valued in recent years.Due to the many factors affecting water inrush and the complicated water inrush mechanism,many factors close to water inrush may have precursory abnormal changes.At present,the existing monitoring and early warning system mainly uses a few monitoring indicators such as groundwater level,water influx,and temperature,and performs water inrush early warning through the abnormal change of a single factor.However,there are relatively few multi-factor comprehensive early warning identification models.Based on the analysis of the abnormal changes of precursor factors in multiple water inrush cases,11 measurable and effective indicators including groundwater flow field,hydrochemical field and temperature field are proposed.Finally,taking Hengyuan coal mine as an example,6 indicators with long-term monitoring data sequences were selected to establish a single-index hierarchical early-warning recognition model,a multi-factor linear recognition model,and a comprehensive intelligent early-warning recognition model.The results show that the correct rate of early warning can reach 95.2%.展开更多
In this paper,the hydrogeological characteristics in the southern coalfields of China are first briefly outlined.Then,taking the Meitanba mine as an example,the evolution and modeling of mine water inflow are studied....In this paper,the hydrogeological characteristics in the southern coalfields of China are first briefly outlined.Then,taking the Meitanba mine as an example,the evolution and modeling of mine water inflow are studied.Finally,the hazard characteristics related to mine water and mud inrush are analyzed.The results show that the main mine water sources in the Meitanba mine area are groundwater,surface water and precipitation.The evolution of mine water inflow with time indicates that the water inflow is closely related to the development of karst structures,the amount of water from rainfall infiltration,and the scope of groundwater depression cone.The mine water inflow increases with time due to the increase in mining depth and the expansion of groundwater depression cone.Using the big well method and following the potential superposition principle,a hydrogeological model considering multi-well interactions has been developed to predict the mine water inflow.Based on the monitored data in the Meitanba mine area over a period of nearly 60 years,it is found that with increasing mining depth,the number of water and mud inrush points tended to decrease.However,the average water and mud flow rate per point tended to increase.展开更多
Coal mining has changed the hydrogeological conditions of river basins,and studying how the relationship among different types of water body has changed under the influence of coal mining is of great significance for ...Coal mining has changed the hydrogeological conditions of river basins,and studying how the relationship among different types of water body has changed under the influence of coal mining is of great significance for understanding the regional hydrological cycle.We analyzed the temporal and spatial distribution of hydrochemical properties and environmental isotopes in the Hailiutu River Basin(HRB),China with a mixed model.The results showed that:(1)human activity(e.g.,coal mining and agricultural production)causes considerable changes in the hydrochemical properties of surface water in and around the mining areas,and leads to significant increases in the concentrations of Na^(+)and SO_(4)^(2-);(2)precipitation is the main source of water vapour in the HRB.The transformation between surface water and groundwater in the natural watershed is mainly affected by precipitation;and(3)in the mining areas,the average contribution rates of precipitation to the recharge of surface water and groundwater increased by 2.6%-7.9%and 2.7%-9.9%,respectively.Groundwater in the Salawusu Formation constitutes up to 61.3%-72.4%of mine water.Overall,this study is beneficial for quantifying the effects of coal mining on local hydrological cycles.The research results can provide a reference for local water resources management and ecological environment improvement.展开更多
Membrane distillation(MD)is a promising membrane separation technique used to treat industrial wastewater.When coupled with cheap heat sources,MD has significant economic advantages.Therefore,MD can be combined with s...Membrane distillation(MD)is a promising membrane separation technique used to treat industrial wastewater.When coupled with cheap heat sources,MD has significant economic advantages.Therefore,MD can be combined with solar energy to realize the large-scale and low-cost treatment of highly mineralized mine water in the western coalproducing region of China.In this study,highly mineralized mine water from the Ningdong area of China was subjected to vacuum MD(VMD)using polyvinylidene fluoride hollow-fiber membranes.The optimal operation parameters of VMD were determined by response surface optimization.Subsequently,the feasibility of VMD for treating highly mineralized mine water was explored.The fouling behavior observed during VMD was further investigated by scanning electron microscopy with energy-dispersive X-ray spectroscopy(SEM-EDS).Under the optimal parameters(pressure=-0.08 MPa,temperature=70℃,and feed flow rate=1.5 L/min),the maximum membrane flux was 8.85 kg/(m^(2) h),and the desalination rate was 99.7%.Membrane fouling could be divided into three stages:membrane wetting,crystallization,and fouling layer formation.Physical cleaning restored the flux and salt rejection rate to 94%and 97%of the initial values,respectively;however,the cleaning interval and cleaning efficiency decreased as the VMD run time increased.SEM-EDS analysis revealed that the reduction in flux was caused by the precipitation of CaCO_(3).The findings also demonstrated that the membrane wetting could be attributed to the formation of NaCl on the cross section and outer surface of the membrane.Overall,the results confirm the feasibility of MD for treating mine water and provide meaningful guidance for the industrial application of MD.展开更多
In the last decade, Mozambique became one of the top coal producers in Africa. The coal mines are in Moatize district in the center of the country, inside the lower Zambezi river basin. Pollution due to mining activit...In the last decade, Mozambique became one of the top coal producers in Africa. The coal mines are in Moatize district in the center of the country, inside the lower Zambezi river basin. Pollution due to mining activities has negative impacts in agriculture, fishing, water supply, and presents risks to public health. Mozambique is one of the largest cassava producers in the world. More than 1.5 million tons of cassava peel are generated in the country and this agro-waste is discarded. The aim of this study is to discuss the possibility of using cassava peel to treat mine water. Cassava peel can be used as carbon sources for sulfate reducing bacteria in bioremediation, as an adsorbent and as a filter medium. An integrated method is proposed for treatment of mine water in Moatize. It was suggested that applying cassava peel generated in developing countries for treatment of mine water could be a good solution to protect the environment against mining pollution.展开更多
For the sake of mine water drainage and sustainable groundwater protection,the new approach of mine water deep geological storage(MWDGS)is highly necessary to save water resources in the semi-arid region of China.Howe...For the sake of mine water drainage and sustainable groundwater protection,the new approach of mine water deep geological storage(MWDGS)is highly necessary to save water resources in the semi-arid region of China.However,up to now,little academic research has been done on mine water geological storage.Given this situation,the hydrogeological feasibility of MWDGS was explored in Baotashan coarse sandstone(BCS)of Jurassic measure in Ordos Basin.The results show that the white-gray BCS with a fragile skeleton of quartz(41.4%),feldspar(21.1%),and clay minerals(16.4%)provides the potential variable-void for mine water;and its hydro-chemical type of BCS aquifer is CO_(3)-Na and Cl-Na.As the burial depth increases,the strong alkaline groundwater is in stagnant and poor recharge-runoff-discharge condition.The lab test shows that the pores whose diameter is over 10μm could be treated as the main storage of mine water;and the effective porosity varies from 1.36%to 3.46%.When mine water is injected,the strong hydrodynamics of mine water storage would change the permeability significantly and about 0.201%soluble solids would be dissolved.Partial clay minerals obstruct the pores and induce the saturated phase of high permeability to evolve into steady phase of lower permeability.Under the condition of nonhydraulic fracturing during continuous storage,the heterogeneous anisotropic medium obtained by Transition PRObability GeoStatistics(TPROGS)shows that the capacity of BCS aquifer is 0.455 to 1.226Mm^(3)for 1 km^(2)in the study area.The simulation shows that the groundwater mound in well-scale and mine-scale would be formed.The groundwater quality characteristics of“Three Zone”would occur around and gradually drop to approximate the original brine within 10 years.The hydrogeological feasibility reveals that this approach is useful for the well design and groundwater environment management during the mine water deep geological storage project in the Ordos basin.展开更多
In order to investigate chromium contamination of coal mine water, to analyze chromium leaching mechanism and to evaluate environment pollution potential of coal mine water, we perform site investigations, physical an...In order to investigate chromium contamination of coal mine water, to analyze chromium leaching mechanism and to evaluate environment pollution potential of coal mine water, we perform site investigations, physical and computer modeling in the Xuzhou-Datun coal mine district. The result of our test samples shows that chromium concentration was 9 μg/L in roof leachate and 3 μg/L in coal leachate. The host rock has a higher pollution potential than that of coal seams. Leaching experiments and XRD test results indicate that chromium is released from the process of transforming illite to kaolinite. The pH, pe and temperature of coal mine water affect the chromium leaching behavior. Modeling results suggest that the adsorption of adsorbents controls chromium concentration in coal mine water. The chromium adsorption ratio is quite low in both an acid and in an alkaline environment. Therefore, coal mine water has a high pollution potential. Under other conditions, chromium adsorption is stronger in a neutral water environment, so that chromium concentrations may be very low.展开更多
The iron and manganese absorption properties of several filter media were studied. Four plain filter media and six surface-modified media were examined. The surface modification was performed using potassium permangan...The iron and manganese absorption properties of several filter media were studied. Four plain filter media and six surface-modified media were examined. The surface modification was performed using potassium permanganate as a surface treatment. The surface-modified manganese sand was found to be most efficient at removing iron and manganese from water. The metal concentrations in filtered effluent were between 0.01 and 0.04 mg/L, which is far lower than the standard for recycle water. A concen-tration of 5% KMnO4 was found to be most effective as surface modifier. The surface of the manganese sand modified by 5% KMnO4 was examined and found to be covered with a dense membrane of some compound. The membrane had the advantages of uniform texture, large surface area and physical and chemical stability. It was effective at removing iron and manganese from mine water.展开更多
In order to understand the mechanism and regularity of the groundwater con- tamination from mine water of abandoned mines,experiments were conducted on an abandoned coal mine in Fuxin,a representative city with lots o...In order to understand the mechanism and regularity of the groundwater con- tamination from mine water of abandoned mines,experiments were conducted on an abandoned coal mine in Fuxin,a representative city with lots of mine water in northeast China.The groundwater pollution from different contaminants of coal-mining voids (total hardness,SO_4^(2-),Cl^-and total Fe) and pollution factors transportation situation in the coal rock were simulated by soil column experiment under the conditions of mine water leach- ing and main water leaching (similar to rainwater leaching),and the water-rock interaction mechanism was discussed during mine water infiltration through saturated coal rock by application of principle of mass conservation,based on physical properties of coal rock,as well as monitored chemical composition.The results show that,compared with the clear water leaching process,trends of change in pollutant concentrations presented different characteristics in the mine water leaching process.Groundwater is contaminated by the water rock interactions such as migration & accumulation,adsorption & transformation, dissolution & desorption and ion exchange during the mine water permeation.The expe- riments also suggest that at first dissolution rate of some kinds of dissoluble salts is high, but it decreases with leaching time,even to zero during both the mine water leaching and main water leaching.展开更多
The removal of Cd, Cu, Ni and Zn from dilute mine water by using several geological materials including pure limestone, sand, carbonaceous limestone and brecciated limestone was performed on a laboratory scale. The re...The removal of Cd, Cu, Ni and Zn from dilute mine water by using several geological materials including pure limestone, sand, carbonaceous limestone and brecciated limestone was performed on a laboratory scale. The results showed that to add geological materials in combination with sodium carbonate injection would notably enhance the efficiency of heavy metal removal to varying degrees. Pure limestone was found the best one among the four materials mentioned above for removing heavy metals from mine water. The removal efficiencies of pure limestone when it is ground as fine as 30–60 meshes are 58.6% for Cd, 100% for Cu, 47.8% for Ni, and 36.8% for Zn at 20℃. The optimum pH is about 8.9 to 9.1. The mechanism of higher effective removal, perhaps, is primarily due to co-precipitation under the control of calcite-related pH value. According to this research, Na2CO3 injection manners, including slug dosing and drip-wise, seemed to have little impact on the efficiency of heavy metal removal.展开更多
In order to realize the prediction of a chaotic time series of mine water discharge,an approach incorporating phase space reconstruction theory and statistical learning theory was studied.A differential entropy ratio ...In order to realize the prediction of a chaotic time series of mine water discharge,an approach incorporating phase space reconstruction theory and statistical learning theory was studied.A differential entropy ratio method was used to determine embedding parameters to reconstruct the phase space.We used a multi-layer adaptive best-fitting parameter search algorithm to estimate the LS-SVM optimal parameters which were adopted to construct a LS-SVM prediction model for the mine water chaotic time series.The results show that the simulation performance of a single-step prediction based on this LS-SVM model is markedly superior to that based on a RBF model.The multi-step prediction results based on LS-SVM model can reflect the development of mine water discharge and can be used for short-term forecasting of mine water discharge.展开更多
The mechanism of mine water inrushes in coal mines in China differs considerably from that in other countries.In China, most water inrushes occur from floor strata, where the water-inrush sources are karstic limestone...The mechanism of mine water inrushes in coal mines in China differs considerably from that in other countries.In China, most water inrushes occur from floor strata, where the water-inrush sources are karstic limestone aquifers.Our study describes the mechanism of mine water inrushes through a fault in the mine floor using principles of strata mechanics and the path of water inrush from an aquifer to the working face.A criterion to judge whether a ground water inrush will occur through a fault or not is also described, together with a case history of water inflow in the Feicheng coalfield, China.展开更多
Reservoirs play an important role in water management and are key elements for water supply.Monitoring is needed in order to guarantee the quantity and quality of stored water.However,this task is sometimes not easy.T...Reservoirs play an important role in water management and are key elements for water supply.Monitoring is needed in order to guarantee the quantity and quality of stored water.However,this task is sometimes not easy.The objective of this study was to develop a procedure for predicting volume of stored water with remote sensing in water bodies under Mediterranean climate conditions.To achieve this objective,multispectral Landsat 7 and 8 images(NASA)were analyzed for the following five reservoirs:La Serena,La Pedrera,Beniarrés,Cubillas and Negratín(Spain).Reservoirs water surface was computed with the spectral angle mapper(SAM)algorithm.After that,cross-validation regression models were computed in order to assess the capability of water surface estimations to predict stored water in each of the reservoirs.The statistical models were trained with Landsat 7 images and were validated by using Landsat 8 images.Our results suggest a good capability of water volume prediction from free satellite imagery derived from surface water estimations.Combining free remote sensing images and open source GIS algorithms can be a very useful tool for water management and an integrated and efficient way to control water storage,especially in low accessible sites.展开更多
Water fluoride pollution has caused non-negligible harm to the environment and humans,and thus it is crucial to find a suitable treatment technology.In this study,La-Fe@PTA adsorbent was synthesized for the defluorida...Water fluoride pollution has caused non-negligible harm to the environment and humans,and thus it is crucial to find a suitable treatment technology.In this study,La-Fe@PTA adsorbent was synthesized for the defluoridation of mine water.The results showed that the optimum conditions for defluoridation by La-Fe@PTA were p H close to 7.0,the initial F-concentration of 10 mg/L,the dosage of 0.5 g/L and the adsorption time of 240 min.Compared with SO_4^(2-),Cl^(-),NO_(3)^(-),Ca^(2+)and Mg^(2+),CO_(3)^(2-)and HCO_(3)^(-)presented severer inhibition on fluoride uptake by La-Fe@PTA.The adsorption process fits well with the pseudo-second-order kinetic model and Freundlich model,and the maximum adsorption capacity of Langmuir model was 95 mg/g.Fixed-bed adsorption results indicated that fluoride in practical fluorinated mine water could be effectively removed from 3.6 mg/L to less than 1.5 mg/L within130 bed volume(BV)by using 1.5 g La-Fe@PTA.Furthermore,the adsorbent still had good adsorption capacity after regeneration,which confirms the great application potential of La-Fe@PTA as a fluoride ion adsorbent.The mechanism analysis showed that La-Fe@PTA adsorption of fluorine ions is a physicochemical reaction driven by electrostatic attraction and ion exchange.展开更多
Taking the Xinhe mine's structure, mine pressure, structural fissure, fault andfault displacement, the distance between fault and water inrush point, thickness of block,water pressure those geological factors whic...Taking the Xinhe mine's structure, mine pressure, structural fissure, fault andfault displacement, the distance between fault and water inrush point, thickness of block,water pressure those geological factors which influenced the water inrush as the independentvariable, based on these data of water inrush point and water uninrush point, usingthe method of quantification theory(Ⅰ,Ⅱ), it would quantitatively disposes the qualitativevariable, applied to calculation to evaluate the risk of Xinhe's water inrush.展开更多
文摘It is of great significance to analyze the chemical indexes of mine water and develop a rapid identification system of water source, which can quickly and accurately distinguish the causes of water inrush and identify the source of water inrush, so as to reduce casualties and economic losses and prevent and control water inrush disasters. Taking Ca<sup>2+</sup>, Mg<sup>2+</sup>, Na<sup>+</sup> + K<sup>+</sup>, , , Cl<sup>-</sup>, pH value and TDS as discriminant indexes, the principal component analysis method was used to reduce the dimension of data, and the identification model of mine water inrush source based on PCA-BP neural network was established. 96 sets of data of different aquifers in Panxie mining area were selected for prediction analysis, and 20 sets of randomly selected data were tested, with an accuracy rate of 95%. The model can effectively reduce data redundancy, has a high recognition rate, and can accurately and quickly identify the water source of mine water inrush.
文摘The study investigates the hydrogeochemical characteristics of some towns in the Abakaliki Basin, comprising, Ishiagu, Aka Eze, Amaseri, Afikpo and Okposi communities, with the aim of sourcing for portable water in the area. The basin is underlain by Albian sediments, essentially shales, in the lowlands, which were affected by low-grade metamorphism that had produced slates. The highlands comprise basic intrusives from episodes of magmatism and metallic ore mineralisation. Injection of brines into the aquifer system and low, seasonal aquifer recharge from rainfall results in poor water quality in the area. The study analyzes the geochemical distribution in water sources in the area and identifies sources of pollutants to guide the better choice of portable water. Results of hydrogeochemical analysis of both surface and groundwater from the communities were compared with World Health Organization to identify portable water locations in the area. While the salt lake at Okposi is the main source of brine intrusion in the study area, the Pb/Zn mine at Ishiagu is the main source of mine-water pollution in the study area. Most chemical parameters, (especially Cl<sup>-</sup>, Na<sup>+</sup>, Ca<sup>2+</sup>, Mg<sup>2+</sup>, SO<sub>4</sub><sup>2-</sup>, HCO<sub>3</sub><sup>-</sup>) maintain high concentrations within the salt lake area, with the values declining away from the salt lake. The main anthropogenic source of pollution in the area, especially at Ishiagu, is the indiscriminate surface mining of lead-zinc without proposer waste management practices. Possible sourcing for portable water in the study area includes a deep borehole at Ishiagu, away from lead-zinc intrusives. At the Okposi axis, searching for portable water in boreholes should target shallower aquifers that do not communicate with the deeper-seated brine zones, likewise targeting zones farther away from these brine-invaded areas. A controlled pumping rate could potentially ensure that the cone of depression was not low enough to reach the brine zone at depth. In addition, desalination could also potentially render the salt water drinkable if properly handled to eliminate the high concentration of salts in the water to the level of acceptable limit by the WHO. Based on the study, the best area to target for portable water in the study area is Afikpo, with most geochemical elements naturally occurring within WHO’s standard concentration while portable water could be harnessed in areas further away from mining sites, especially at deep groundwater.
基金financially supported by the National Key Research and Development Program of China(No.2019YFC1805400)。
文摘As a new technical means that can detect abnormal signs of water inrush in advance and give an early warning,the automatic monitoring and early warning of water inrush in mines has been widely valued in recent years.Due to the many factors affecting water inrush and the complicated water inrush mechanism,many factors close to water inrush may have precursory abnormal changes.At present,the existing monitoring and early warning system mainly uses a few monitoring indicators such as groundwater level,water influx,and temperature,and performs water inrush early warning through the abnormal change of a single factor.However,there are relatively few multi-factor comprehensive early warning identification models.Based on the analysis of the abnormal changes of precursor factors in multiple water inrush cases,11 measurable and effective indicators including groundwater flow field,hydrochemical field and temperature field are proposed.Finally,taking Hengyuan coal mine as an example,6 indicators with long-term monitoring data sequences were selected to establish a single-index hierarchical early-warning recognition model,a multi-factor linear recognition model,and a comprehensive intelligent early-warning recognition model.The results show that the correct rate of early warning can reach 95.2%.
基金This research is supported by the National Natural Science Foundation of China(Nos.51774131,51874133)Construction Project of Chenzhou National Sustainable Development Agenda Innovation Demonstration Zone(2021sfQ18).
文摘In this paper,the hydrogeological characteristics in the southern coalfields of China are first briefly outlined.Then,taking the Meitanba mine as an example,the evolution and modeling of mine water inflow are studied.Finally,the hazard characteristics related to mine water and mud inrush are analyzed.The results show that the main mine water sources in the Meitanba mine area are groundwater,surface water and precipitation.The evolution of mine water inflow with time indicates that the water inflow is closely related to the development of karst structures,the amount of water from rainfall infiltration,and the scope of groundwater depression cone.The mine water inflow increases with time due to the increase in mining depth and the expansion of groundwater depression cone.Using the big well method and following the potential superposition principle,a hydrogeological model considering multi-well interactions has been developed to predict the mine water inflow.Based on the monitored data in the Meitanba mine area over a period of nearly 60 years,it is found that with increasing mining depth,the number of water and mud inrush points tended to decrease.However,the average water and mud flow rate per point tended to increase.
基金This research was supported by the National Key Research and Development Program of China(2018YFC0406401)the Inner Mongolia Autonomous Region“Grassland Talents”Project.
文摘Coal mining has changed the hydrogeological conditions of river basins,and studying how the relationship among different types of water body has changed under the influence of coal mining is of great significance for understanding the regional hydrological cycle.We analyzed the temporal and spatial distribution of hydrochemical properties and environmental isotopes in the Hailiutu River Basin(HRB),China with a mixed model.The results showed that:(1)human activity(e.g.,coal mining and agricultural production)causes considerable changes in the hydrochemical properties of surface water in and around the mining areas,and leads to significant increases in the concentrations of Na^(+)and SO_(4)^(2-);(2)precipitation is the main source of water vapour in the HRB.The transformation between surface water and groundwater in the natural watershed is mainly affected by precipitation;and(3)in the mining areas,the average contribution rates of precipitation to the recharge of surface water and groundwater increased by 2.6%-7.9%and 2.7%-9.9%,respectively.Groundwater in the Salawusu Formation constitutes up to 61.3%-72.4%of mine water.Overall,this study is beneficial for quantifying the effects of coal mining on local hydrological cycles.The research results can provide a reference for local water resources management and ecological environment improvement.
基金This research was supported by the Open Fund Project of the State Key Laboratory of Water Resources Protection and Utilization in Coal Mining(GJNY-18-73.13).
文摘Membrane distillation(MD)is a promising membrane separation technique used to treat industrial wastewater.When coupled with cheap heat sources,MD has significant economic advantages.Therefore,MD can be combined with solar energy to realize the large-scale and low-cost treatment of highly mineralized mine water in the western coalproducing region of China.In this study,highly mineralized mine water from the Ningdong area of China was subjected to vacuum MD(VMD)using polyvinylidene fluoride hollow-fiber membranes.The optimal operation parameters of VMD were determined by response surface optimization.Subsequently,the feasibility of VMD for treating highly mineralized mine water was explored.The fouling behavior observed during VMD was further investigated by scanning electron microscopy with energy-dispersive X-ray spectroscopy(SEM-EDS).Under the optimal parameters(pressure=-0.08 MPa,temperature=70℃,and feed flow rate=1.5 L/min),the maximum membrane flux was 8.85 kg/(m^(2) h),and the desalination rate was 99.7%.Membrane fouling could be divided into three stages:membrane wetting,crystallization,and fouling layer formation.Physical cleaning restored the flux and salt rejection rate to 94%and 97%of the initial values,respectively;however,the cleaning interval and cleaning efficiency decreased as the VMD run time increased.SEM-EDS analysis revealed that the reduction in flux was caused by the precipitation of CaCO_(3).The findings also demonstrated that the membrane wetting could be attributed to the formation of NaCl on the cross section and outer surface of the membrane.Overall,the results confirm the feasibility of MD for treating mine water and provide meaningful guidance for the industrial application of MD.
文摘In the last decade, Mozambique became one of the top coal producers in Africa. The coal mines are in Moatize district in the center of the country, inside the lower Zambezi river basin. Pollution due to mining activities has negative impacts in agriculture, fishing, water supply, and presents risks to public health. Mozambique is one of the largest cassava producers in the world. More than 1.5 million tons of cassava peel are generated in the country and this agro-waste is discarded. The aim of this study is to discuss the possibility of using cassava peel to treat mine water. Cassava peel can be used as carbon sources for sulfate reducing bacteria in bioremediation, as an adsorbent and as a filter medium. An integrated method is proposed for treatment of mine water in Moatize. It was suggested that applying cassava peel generated in developing countries for treatment of mine water could be a good solution to protect the environment against mining pollution.
基金Fundamental Research Funds for the Universities,Grant/Award Numbers:2020ZDPY0201,2022QN1061National Key Research and Development Project of China,Grant/Award Number:2019YFC1805400+1 种基金National Science Foundation of Jiangsu Province,Grant/Award Number:BK20210524National Natural Science Foundation,Grant/Award Number:42202268。
文摘For the sake of mine water drainage and sustainable groundwater protection,the new approach of mine water deep geological storage(MWDGS)is highly necessary to save water resources in the semi-arid region of China.However,up to now,little academic research has been done on mine water geological storage.Given this situation,the hydrogeological feasibility of MWDGS was explored in Baotashan coarse sandstone(BCS)of Jurassic measure in Ordos Basin.The results show that the white-gray BCS with a fragile skeleton of quartz(41.4%),feldspar(21.1%),and clay minerals(16.4%)provides the potential variable-void for mine water;and its hydro-chemical type of BCS aquifer is CO_(3)-Na and Cl-Na.As the burial depth increases,the strong alkaline groundwater is in stagnant and poor recharge-runoff-discharge condition.The lab test shows that the pores whose diameter is over 10μm could be treated as the main storage of mine water;and the effective porosity varies from 1.36%to 3.46%.When mine water is injected,the strong hydrodynamics of mine water storage would change the permeability significantly and about 0.201%soluble solids would be dissolved.Partial clay minerals obstruct the pores and induce the saturated phase of high permeability to evolve into steady phase of lower permeability.Under the condition of nonhydraulic fracturing during continuous storage,the heterogeneous anisotropic medium obtained by Transition PRObability GeoStatistics(TPROGS)shows that the capacity of BCS aquifer is 0.455 to 1.226Mm^(3)for 1 km^(2)in the study area.The simulation shows that the groundwater mound in well-scale and mine-scale would be formed.The groundwater quality characteristics of“Three Zone”would occur around and gradually drop to approximate the original brine within 10 years.The hydrogeological feasibility reveals that this approach is useful for the well design and groundwater environment management during the mine water deep geological storage project in the Ordos basin.
基金Our study was funded by the National Natural Science Foundation of China (Nos.40572095, 40730422 and 40772102)the Six Projects Sponsoring Talent Summits of Jiangsu Province and the Jiangsu Province Plan of Post-Graduate Student Inno-vation (No.CX07B-050z)
文摘In order to investigate chromium contamination of coal mine water, to analyze chromium leaching mechanism and to evaluate environment pollution potential of coal mine water, we perform site investigations, physical and computer modeling in the Xuzhou-Datun coal mine district. The result of our test samples shows that chromium concentration was 9 μg/L in roof leachate and 3 μg/L in coal leachate. The host rock has a higher pollution potential than that of coal seams. Leaching experiments and XRD test results indicate that chromium is released from the process of transforming illite to kaolinite. The pH, pe and temperature of coal mine water affect the chromium leaching behavior. Modeling results suggest that the adsorption of adsorbents controls chromium concentration in coal mine water. The chromium adsorption ratio is quite low in both an acid and in an alkaline environment. Therefore, coal mine water has a high pollution potential. Under other conditions, chromium adsorption is stronger in a neutral water environment, so that chromium concentrations may be very low.
基金provided by the National Hi-tech Research and Development Program of China (No.2008AA06z305)the National Natural Science Foundation of China (No.50678172)the Science and Technology Research Program of the Ministry of Education of China (No.107022)
文摘The iron and manganese absorption properties of several filter media were studied. Four plain filter media and six surface-modified media were examined. The surface modification was performed using potassium permanganate as a surface treatment. The surface-modified manganese sand was found to be most efficient at removing iron and manganese from water. The metal concentrations in filtered effluent were between 0.01 and 0.04 mg/L, which is far lower than the standard for recycle water. A concen-tration of 5% KMnO4 was found to be most effective as surface modifier. The surface of the manganese sand modified by 5% KMnO4 was examined and found to be covered with a dense membrane of some compound. The membrane had the advantages of uniform texture, large surface area and physical and chemical stability. It was effective at removing iron and manganese from mine water.
基金the National Natural Science Foundation of China(50434020,50374042)Science & Technology Found of Liaoning Province(20022155)Specialized Research Fund for the Doctoral Program of Higher Education(20040147003)
文摘In order to understand the mechanism and regularity of the groundwater con- tamination from mine water of abandoned mines,experiments were conducted on an abandoned coal mine in Fuxin,a representative city with lots of mine water in northeast China.The groundwater pollution from different contaminants of coal-mining voids (total hardness,SO_4^(2-),Cl^-and total Fe) and pollution factors transportation situation in the coal rock were simulated by soil column experiment under the conditions of mine water leach- ing and main water leaching (similar to rainwater leaching),and the water-rock interaction mechanism was discussed during mine water infiltration through saturated coal rock by application of principle of mass conservation,based on physical properties of coal rock,as well as monitored chemical composition.The results show that,compared with the clear water leaching process,trends of change in pollutant concentrations presented different characteristics in the mine water leaching process.Groundwater is contaminated by the water rock interactions such as migration & accumulation,adsorption & transformation, dissolution & desorption and ion exchange during the mine water permeation.The expe- riments also suggest that at first dissolution rate of some kinds of dissoluble salts is high, but it decreases with leaching time,even to zero during both the mine water leaching and main water leaching.
基金granted by the Science Foundation of China Postdoctors (No. 20070420214)the Natural Science Foundation of Shaanxi Province (No. SJ08D03)
文摘The removal of Cd, Cu, Ni and Zn from dilute mine water by using several geological materials including pure limestone, sand, carbonaceous limestone and brecciated limestone was performed on a laboratory scale. The results showed that to add geological materials in combination with sodium carbonate injection would notably enhance the efficiency of heavy metal removal to varying degrees. Pure limestone was found the best one among the four materials mentioned above for removing heavy metals from mine water. The removal efficiencies of pure limestone when it is ground as fine as 30–60 meshes are 58.6% for Cd, 100% for Cu, 47.8% for Ni, and 36.8% for Zn at 20℃. The optimum pH is about 8.9 to 9.1. The mechanism of higher effective removal, perhaps, is primarily due to co-precipitation under the control of calcite-related pH value. According to this research, Na2CO3 injection manners, including slug dosing and drip-wise, seemed to have little impact on the efficiency of heavy metal removal.
基金supported by the Science and Research projects for Ph.D. candidates in the faculty of Xuzhou Normal University (No.08XLR12)Natural Science Foundation of Xuzhou Normal University (No.09XLA10)
文摘In order to realize the prediction of a chaotic time series of mine water discharge,an approach incorporating phase space reconstruction theory and statistical learning theory was studied.A differential entropy ratio method was used to determine embedding parameters to reconstruct the phase space.We used a multi-layer adaptive best-fitting parameter search algorithm to estimate the LS-SVM optimal parameters which were adopted to construct a LS-SVM prediction model for the mine water chaotic time series.The results show that the simulation performance of a single-step prediction based on this LS-SVM model is markedly superior to that based on a RBF model.The multi-step prediction results based on LS-SVM model can reflect the development of mine water discharge and can be used for short-term forecasting of mine water discharge.
基金Projects Y2007F46 supported by the Natural Science Foundation of Shandong Province20070424005 by the Doctor Disciplines Special Scientific Researc Foundation of the Ministry of Education+1 种基金108158 by the Key Project of the Ministry of Education of China50539080 by the National Natural Scienc Foundation of China
文摘The mechanism of mine water inrushes in coal mines in China differs considerably from that in other countries.In China, most water inrushes occur from floor strata, where the water-inrush sources are karstic limestone aquifers.Our study describes the mechanism of mine water inrushes through a fault in the mine floor using principles of strata mechanics and the path of water inrush from an aquifer to the working face.A criterion to judge whether a ground water inrush will occur through a fault or not is also described, together with a case history of water inflow in the Feicheng coalfield, China.
文摘Reservoirs play an important role in water management and are key elements for water supply.Monitoring is needed in order to guarantee the quantity and quality of stored water.However,this task is sometimes not easy.The objective of this study was to develop a procedure for predicting volume of stored water with remote sensing in water bodies under Mediterranean climate conditions.To achieve this objective,multispectral Landsat 7 and 8 images(NASA)were analyzed for the following five reservoirs:La Serena,La Pedrera,Beniarrés,Cubillas and Negratín(Spain).Reservoirs water surface was computed with the spectral angle mapper(SAM)algorithm.After that,cross-validation regression models were computed in order to assess the capability of water surface estimations to predict stored water in each of the reservoirs.The statistical models were trained with Landsat 7 images and were validated by using Landsat 8 images.Our results suggest a good capability of water volume prediction from free satellite imagery derived from surface water estimations.Combining free remote sensing images and open source GIS algorithms can be a very useful tool for water management and an integrated and efficient way to control water storage,especially in low accessible sites.
基金supported by the National Natural Science Foundation of China(No.51978658)。
文摘Water fluoride pollution has caused non-negligible harm to the environment and humans,and thus it is crucial to find a suitable treatment technology.In this study,La-Fe@PTA adsorbent was synthesized for the defluoridation of mine water.The results showed that the optimum conditions for defluoridation by La-Fe@PTA were p H close to 7.0,the initial F-concentration of 10 mg/L,the dosage of 0.5 g/L and the adsorption time of 240 min.Compared with SO_4^(2-),Cl^(-),NO_(3)^(-),Ca^(2+)and Mg^(2+),CO_(3)^(2-)and HCO_(3)^(-)presented severer inhibition on fluoride uptake by La-Fe@PTA.The adsorption process fits well with the pseudo-second-order kinetic model and Freundlich model,and the maximum adsorption capacity of Langmuir model was 95 mg/g.Fixed-bed adsorption results indicated that fluoride in practical fluorinated mine water could be effectively removed from 3.6 mg/L to less than 1.5 mg/L within130 bed volume(BV)by using 1.5 g La-Fe@PTA.Furthermore,the adsorbent still had good adsorption capacity after regeneration,which confirms the great application potential of La-Fe@PTA as a fluoride ion adsorbent.The mechanism analysis showed that La-Fe@PTA adsorption of fluorine ions is a physicochemical reaction driven by electrostatic attraction and ion exchange.
文摘Taking the Xinhe mine's structure, mine pressure, structural fissure, fault andfault displacement, the distance between fault and water inrush point, thickness of block,water pressure those geological factors which influenced the water inrush as the independentvariable, based on these data of water inrush point and water uninrush point, usingthe method of quantification theory(Ⅰ,Ⅱ), it would quantitatively disposes the qualitativevariable, applied to calculation to evaluate the risk of Xinhe's water inrush.
