Total contents of heavy metals ( Pb, Cr, Cd, Hg, As, Cu, Zn, and Ni) in 68 soil samples were determined to evaluate the contamination level of soil from five coal mine areas in Xingren County, Guizhou province. The ...Total contents of heavy metals ( Pb, Cr, Cd, Hg, As, Cu, Zn, and Ni) in 68 soil samples were determined to evaluate the contamination level of soil from five coal mine areas in Xingren County, Guizhou province. The pollution levels of heavy metals were characterized by anthro- pogenic influence multiple, and the pollution of heavy metal in soil was evaluated using geo-accumulation index. Based on the health risk models recommended by the U.S. Environmental Protection Agency ( US EPA), the health risks of heavy metals in the soils were assessed. The results showed that the abandoned land in the five coal mining areas were contaminated by heavy metals, and the order of pollution levels of eight heavy metals was As 〉 Pb 〉 Cu 〉 Hg 〉 Ni 〉 Cr 〉 Cd 〉 Zn. The soils suffered moderate-heavy pollution from As and Pb, and the contents of As and Pb in the soils were 13.16 and 4.76 times higher than the background values of Guizhou Province, followed by Cu, Hg and Ni , while soil pollution from Cr, Cd and Zn was mild. The order of non-caminogenic risks of the heavy metals in the soils was As 〉 Pb 〉 Cr 〉 Ni 〉 Cu 〉 Hg 〉 Cd 〉 Zn, and the non-carcinogenic dsk value of As was higher than that its threshold value 1, which indicated that As had a high potential health risk to adults and children. The order of carcinogen risks of the four heavy metals was As 〉 Cd 〉 Cr 〉 Ni, and the carcinogenic risk value of As was higher than its threshold value, indicating that As had a high carcinogenic risk to adults and children. The carcinogenic risk values of other three heavy metals ( Cd, Cr and Ni) were lower than the threshold value, so they had no carcinogenic risk to human health. Moreover, children were more sensitively affect- ed by heavy metals from the abandoned land. Therefore, the health of children in such areas should be paid more attention to. The HI value of the eight heavy metals to children was seven times higher than that to adults. The contribution rate of HQAs to HI was about 88%, and the contribution rate of CRA, to TCR was about 98%, so As was the most crucial factor influencing non-carcinogenic and carcinogenic dsk in the abandoned soils.展开更多
Atmospheric pressure fuctuation is one of the most important factors afecting the climate environment and gas emission in the fre area.To obtain the infuence rule of the surface atmospheric pressure change on the gas ...Atmospheric pressure fuctuation is one of the most important factors afecting the climate environment and gas emission in the fre area.To obtain the infuence rule of the surface atmospheric pressure change on the gas sampling and abnormal emission in the mine closed goaf,the No.1 coal mine in Dananhu was taken as the research object.Using Fourier transform and Fisher harmonic analysis and other statistical methods,the infuence of the periodic variation of atmospheric pressure on the gas leakage and outfow in the closed goaf was studied.The results showed that there were three atmospheric pressure periods of 15.2 d,1 d and 182.2 d,and the probability was greater than 95%.The time period with the highest number of atmospheric pressure peaks was 7:00–8:00,which accounted for 20.2%of total occurrence number in a day.And the time periods with the highest number of atmospheric pressure trough were 2:00,15:00 and 16:00,accounting for 27.4%.The peak-to-trough transition time was mainly concentrated around 6 h,and the diurnal variation curve of atmospheric pressure was mainly bimodal.The atmospheric pressure change rate was mostly concentrated in 10–50 Pa/h.It was determined that the distance that the gas sampling pipe was pre-laid into the inner side of the closed wall should be greater than 44.4 m,and the CO concentration and atmospheric pressure in the closed goaf were both periodic and negative with atmospheric pressure.The research results have important guiding signifcance for the monitoring,early warning and environmental protection of the goaf.展开更多
Coal is the vital resource of energy in China,but abandoned coal ash and gangue lead to the degradation of vegetation cover and reduce soil quality.Both arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing ba...Coal is the vital resource of energy in China,but abandoned coal ash and gangue lead to the degradation of vegetation cover and reduce soil quality.Both arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB) play a key role in biogeochemical cycle such as soil organic matter decomposition,nutrition release,and energy flow.To improve and reclamation the soil quality and ecological efficiency of the coal mining waste,we investigated the effects of an AMF strain (Glomus mosseae) and a PSB strain (Pantoesstewarti) on phytate mineralization and subsequent transfer to the host plant (Medicago sativa L.) using a two-compartment microcosm with a central 30 mm nylon mesh barrier.The results showed that significantly higher available P (AP),above ground biomass (AGB) and underground biomass (UGB) were in combined inoculation of AMF-PSB than other treatments in root and hyphae compartment.The microbial inoculum of the AMF or PSB had a significant influence on soil acid phosphatase activities (ACP).AMF-PSB enhanced phytate mineralization,improved plant biomass.AP and ACP positively influenced the AGB and UGB.AMF-PSB could be used as bioinoculant to enhance sustainable production of the plant in abandoned solid waste of coal mine.展开更多
The discharge of acid mine drainage from abandoned high sulfur(S)coal mines has caused serious pollution in the Shandi River,Yangquan,Shanxi Province.To determine the impact of long-term acid mine drainage on the micr...The discharge of acid mine drainage from abandoned high sulfur(S)coal mines has caused serious pollution in the Shandi River,Yangquan,Shanxi Province.To determine the impact of long-term acid mine drainage on the microorganisms in the river,we collected river sediments from a polluted tributary(Group P)and the mainstream of Shandi River(Group R)to study the bacterial diversity and community composition.The results showed that the tributary was seriously polluted by acid drainage from abandoned coal mines,with the pH value of the sediment being<2.5,resulting in the low bacterial richness and diversity of the tributary samples.Acidophillic Fe-and S-metabolizing bacteria,such as Metallibacterium,Acidiphilium,and Acidithiobacillus,were the dominant genera in Group P samples,while the Group R was dominated by the neutral anaerobic iron-reducing bacteria Geothrix and Geobacter.Results of principal co-ordinates analysis(PCoA)revealed that the bacterial communities are significantly different between groups P and R,and the significant different species were mainly attributed to phylum Proteobacteria,Actinobacteria,and Acidobacteria.The distribution of the microbial community is mainly influenced by pH,and the Fe and Cd concentrations.Metallicactrium,the dominant genus,is negatively correlated with pH(R^(2)=-0.95)and positively correlated with Fe(R^(2)=0.99),while Geothrix and Geobacter,are mainly affected by the heavy metals.This study determined the impact of river pollution caused by abandoned coal mine drainage,especially on the microbial diversity and community composition within the river sediment.展开更多
The seasonal and spatial changes in the chemical composition of the water in abandoned mine drainages and rivers in Yudong River area in the years of 2017-2018 were analyzed.The effects of mine water drainage on the s...The seasonal and spatial changes in the chemical composition of the water in abandoned mine drainages and rivers in Yudong River area in the years of 2017-2018 were analyzed.The effects of mine water drainage on the seasonality and physicochemical properties of the river water after mine closure were evaluated,and the feasibility of irrigation using river water and the degree of pollution to farmland were assessed using the Water Quality Standard for Farmland Irrigation.The results show that the mine water has low pH value(<3.5-4)and high levels of total hardness,SO_(4)^(2−),Fe,Al,and Zn.In addition,the pH of the mine water is negatively correlated with the presence of other metal ions.The correlation coefficient between the chemical oxygen demand(COD)and Fe reached 0.989.While the pollution levels of Pinglu and Baishui rivers were low,the confluence region of the two rivers was seriously polluted.However,only the levels of Fe and Cd slightly exceeded the Surface Water Environmental Quality Standard after the confluence of Yudong and Chongan rivers.Overall,the heavy pollution type of the confluent river is consistent with mine water pollution.The water quality is slightly better in the dry season compared than in the high-water period.Sulfate and Fe content decreased by 39 and 16 mg/L,respectively,and Cd content decreased two-fold.Despite these findings,this study shows that from 2017 to 2018,the pH and Cd content of the rivers at the confluence exceeded the irrigation limit and the water quality continued to deteriorate,which may pose a soil contamination risk.Long-term use of the river for irrigation water may cause toxic elements such as Cd,Fe,Mn,SO_(4)^(2−),Al,and F-to enter the food chain,thereby endangering the life and health of villagers in Yudong River area.展开更多
With the increasingly prominent environmental problems of abandoned coal mines,this paper discussed the significance of environmental vulnerability assessment of abandoned coal mines.Environmental vulnerability assess...With the increasingly prominent environmental problems of abandoned coal mines,this paper discussed the significance of environmental vulnerability assessment of abandoned coal mines.Environmental vulnerability assessment is essentially an assessment of environmental quality.At present,the research object of environmental impact assessment method and program of mine is mostly single factor.However,the impact of abandoned coal mine on the environment is multifaceted,which was summarized into nine prominent common problems.Based on these nine factors,the environmental vulnerability assessment model of abandoned coal mine based on multifactor evaluation was established by using the analytic hierarchy process(AHP)method,the ranking criteria of nine factor indexes was proposed,the evaluation process was established,and the evaluation index system of environmental vulnerability of abandoned coal mines was established.The environmental vulnerability assessment method of abandoned coal mines has universal applicability,which can provide the basis for the government and enterprises to carry out treatment and planning of abandoned coal mine and promote the optimization of governance effect.展开更多
Lipovtsy coal field mine №4 processed north-western reserves of Lipovtsy field in Primorski Krai (Russia). In 1997, the mine was declared unprofitable and was abandoned by natural flooding with no arrangement of mine...Lipovtsy coal field mine №4 processed north-western reserves of Lipovtsy field in Primorski Krai (Russia). In 1997, the mine was declared unprofitable and was abandoned by natural flooding with no arrangement of mine water discharge and in 2005 it was fully flooded. The main sources of pollution in the studied area are spoil heaps (mine wastes), underspoil filtering waters and mine waters which are being discharged on the surface after finishing of “hydraulic funnel” artificial support. The study of technogenic landscape of abandoned mine industrial area showed that its morphologic form is dominated by spoil heaps. Soils located near mine waste body differ from benchmark soils by chemical properties and size distribution. The influence of active hydrochemical mine and drainage water flows is the reason of the above-mentioned variation in soil properties. Results showed that, there exist a high correlation ratios between chemical composition of mine waters and water extracts from soil: Between the alkalinity of mine waters and electrical conductivity of soil water extracts (r = 0.73), between mine water iron content and pH of soil water extract (r = −0.56), between the solid residue of mine waters and electrical conductivity of soil water extracts (r = 0.72), between the mine waters calcium content and electrical conductivity of soil water extracts (r = −0.75), between the alkalinity of mine waters and silicon dioxide content of soil water extracts (r = 0.61), between the mineralization of mine waters and chrome content of soil water extracts (r = 0.73).展开更多
In multi-seam mining,the interlayer rock strata between the upper coal seam(UCS)and the lower coal seam(LCS)appear damage and strength weakening after mining the UCS.Ground stability control of the gob-side entry reta...In multi-seam mining,the interlayer rock strata between the upper coal seam(UCS)and the lower coal seam(LCS)appear damage and strength weakening after mining the UCS.Ground stability control of the gob-side entry retaining(GER)under the gob with close distance coal seams(CDCS)is faced with difficulties due to little attention to GER under this condition.This paper focuses on surrounding rock stability control and technical parameters design for GER under the gob with CDCS.The floor rock strata damage characteristics after mining the UCS is first evaluated and the damage factor of the interlayer rock strata below the UCS is also determined.Then,a structural mechanics model of GER surrounding rock is set up to obtain the main design parameters of the side-roadway backfill body(SBB)including the maximum and minimum SBB width calculation formula.The optimal SBB width and the water-to-cement ratio of high water quick-setting material(HWQM)to construct the SBB are determined as 1.2 m and 1.5:1.0,respectively.Finally,engineering trial tests of GER are successfully carried out at#5210 track transportation roadway of Xingwu Colliery.Research results can guide GER design under similar mining and geological conditions.展开更多
In the Kaiping Coal field,mining of five coal seams,located within 80 m in the Kailuan Group,#5,#7,#8,#9 and#12 coal seam,is difficult due to small interburden thickness,concentrated stress distributions,high coal sea...In the Kaiping Coal field,mining of five coal seams,located within 80 m in the Kailuan Group,#5,#7,#8,#9 and#12 coal seam,is difficult due to small interburden thickness,concentrated stress distributions,high coal seam metamorphism,and complex geological conditions.By using the ZTR12 geological penetration radar(GPR)survey combined with borehole observations,the overburden caving due to mining of the five coals seams was measured.The development characteristics of full-cover rock fractures after mining were obtained from the GPR scan,which provides a measurement basis for the control of rock strata in close multiple coal seam mining.For the first time,it was found that the overburden caving pattern shows a periodic triangular caved characteristic.Furthermore,it is proposed that an upright triangular collapsed pile masonry and an inverted triangular with larger fragments piled up alternately appear in the lower gob.The research results show that the roof structure formed in the gob area can support the key overlying strata,which is beneficial to ensure the integrity and stability of the upper coal seams in multiple-seam mining of close coal seams.展开更多
A roadway within ultra-close multiple-seams(RUCMSs) is one of the most difficult supported coal roadways to deal with in underground coal mines. This is usually due to the unknown stress distributions, improper roadwa...A roadway within ultra-close multiple-seams(RUCMSs) is one of the most difficult supported coal roadways to deal with in underground coal mines. This is usually due to the unknown stress distributions, improper roadway layout, and unreasonable support parameters. In order to solve this support problem and effectively save RUCMSs from frequent and abrupt disasters(such as serious deformation of the surrounding rock, roof cave ins, and coal side collapse), a comprehensive method is adopted here which includes theoretical analysis, numerical simulation, and field monitoring. A mechanical model was constructed to determine the stress distribution in the coal pillar after two sides of a longwall panel had been mined. Based on this model, the horizontal, vertical, and tangential stress equations for the plane below the floor of the upper-left coal pillar were deduced. In addition, a typical coal mine(the Jinggonger colliery, located in Shuozhou city, Shanxi province, China) with an average distance between its 9# and 11# coal seams of less than 8.0 was chosen to conduct research on the proper layout and reasonable support required for a typical coal roadway located within coal seam 11#. Using FLAC3D(Fast Lagrangian Analysis of Continua in 3-Dimensions) numerical software, eight schemes were designed with different horizontal distances(d) between the center lines of the coal pillar and the roadway in the lower coal seam(RLCS). The simulations and detailed analysis indicate that the proper distances required are between 22.5 and 27.5 m. A total of 20 simulation schemes were used to investigate the factors influencing the support provided by the key bolts(bolt length, spacing, distance between two rows, installation angle, and pre-tightening force). The results were analyzed and used to determine reasonable values for the support parameters. Field results show that the stability and strength of the RLCS can be effectively safeguarded using a combination of researched stress distribution characteristics, proper layout of the RLCS, and correct support parameters.展开更多
The paper presents the mining method for the close quarter coal seams with thin rock sheet, that is mining the low coal seam, recovering the top coal seam after putting down the roof rock of the low coal seam. Practic...The paper presents the mining method for the close quarter coal seams with thin rock sheet, that is mining the low coal seam, recovering the top coal seam after putting down the roof rock of the low coal seam. Practice has proved that in recovering the top coal outside the face width after the rock between seams falls naturally or is demolished, the technology is simple, easy to operate and does not make a great demand for technical equipment. In the process of recovering the top coal, the low seam support could not be affected seriously, and two seams mining could be coordinated. Compared with the individual mining method, this mining method can produce a better economic benefit.展开更多
面向“30·60”双碳目标,矿区能源利用方式的绿色、经济、高效转型成为我国能源革命的迫切需求。西部矿区拥有丰富的可再生能源资源禀赋,但仍面临着可再生能源就地消纳困难,电力设备投资成本高、利用率低以及外送输电通道有限的困...面向“30·60”双碳目标,矿区能源利用方式的绿色、经济、高效转型成为我国能源革命的迫切需求。西部矿区拥有丰富的可再生能源资源禀赋,但仍面临着可再生能源就地消纳困难,电力设备投资成本高、利用率低以及外送输电通道有限的困难。为提升矿区用能清洁化程度,提升矿区能源供给的稳定性与可靠性,增强矿区对外部电网的支撑能力,提出全清洁能源下的高品质矿区能源系统(High-quality Coal Mine Energy System,HCMES)及其配置优化方法。首先,考虑西部矿山综合能源系统的负荷特点与伴生能源利用,结合可再生能源发电与废弃矿井抽水蓄能,构建全清洁能源下的HCMES架构。其次,考虑到矿区生产全流程负荷的需求响应能力,考虑系统的能量平衡约束,提出全清洁能源下的高品质矿区能源系统优化配置模型。最后,以系统年平均综合成本最小化为目标,将原问题转化为混合整数线性规划模型,求解生成高品质矿区能源系统优化配置方案。以我国西部某年产煤量1200万t的矿区实际数据为实例,验证所提模型与方法的有效性,并分析可再生能源出力与生产负荷需求不确定性对系统优化配置结果的影响。算例仿真设置了4种矿区能源系统配置方式:不配置储能、配置抽水蓄能、配置电化学储能、配置抽水蓄能(不外购电能)。结果表明,所提出的HCMES相较于其他配置方式可减少电气一次设备投资11.11%,相较于方式3可降低年平均综合成本7.91%,且最多可减少矿区生产用能总二氧化碳排放量91.17%。展开更多
基金Supported by the National Natural Science Foundation of China(21467005)
文摘Total contents of heavy metals ( Pb, Cr, Cd, Hg, As, Cu, Zn, and Ni) in 68 soil samples were determined to evaluate the contamination level of soil from five coal mine areas in Xingren County, Guizhou province. The pollution levels of heavy metals were characterized by anthro- pogenic influence multiple, and the pollution of heavy metal in soil was evaluated using geo-accumulation index. Based on the health risk models recommended by the U.S. Environmental Protection Agency ( US EPA), the health risks of heavy metals in the soils were assessed. The results showed that the abandoned land in the five coal mining areas were contaminated by heavy metals, and the order of pollution levels of eight heavy metals was As 〉 Pb 〉 Cu 〉 Hg 〉 Ni 〉 Cr 〉 Cd 〉 Zn. The soils suffered moderate-heavy pollution from As and Pb, and the contents of As and Pb in the soils were 13.16 and 4.76 times higher than the background values of Guizhou Province, followed by Cu, Hg and Ni , while soil pollution from Cr, Cd and Zn was mild. The order of non-caminogenic risks of the heavy metals in the soils was As 〉 Pb 〉 Cr 〉 Ni 〉 Cu 〉 Hg 〉 Cd 〉 Zn, and the non-carcinogenic dsk value of As was higher than that its threshold value 1, which indicated that As had a high potential health risk to adults and children. The order of carcinogen risks of the four heavy metals was As 〉 Cd 〉 Cr 〉 Ni, and the carcinogenic risk value of As was higher than its threshold value, indicating that As had a high carcinogenic risk to adults and children. The carcinogenic risk values of other three heavy metals ( Cd, Cr and Ni) were lower than the threshold value, so they had no carcinogenic risk to human health. Moreover, children were more sensitively affect- ed by heavy metals from the abandoned land. Therefore, the health of children in such areas should be paid more attention to. The HI value of the eight heavy metals to children was seven times higher than that to adults. The contribution rate of HQAs to HI was about 88%, and the contribution rate of CRA, to TCR was about 98%, so As was the most crucial factor influencing non-carcinogenic and carcinogenic dsk in the abandoned soils.
基金This work was financially sponsored by the National Natural Science Foundation of China(51864045,51804161,52074156 and 51804355)And Central University Basic Scientifc Research Business Expenses Special Funds(2023ZKPYAQ03).
文摘Atmospheric pressure fuctuation is one of the most important factors afecting the climate environment and gas emission in the fre area.To obtain the infuence rule of the surface atmospheric pressure change on the gas sampling and abnormal emission in the mine closed goaf,the No.1 coal mine in Dananhu was taken as the research object.Using Fourier transform and Fisher harmonic analysis and other statistical methods,the infuence of the periodic variation of atmospheric pressure on the gas leakage and outfow in the closed goaf was studied.The results showed that there were three atmospheric pressure periods of 15.2 d,1 d and 182.2 d,and the probability was greater than 95%.The time period with the highest number of atmospheric pressure peaks was 7:00–8:00,which accounted for 20.2%of total occurrence number in a day.And the time periods with the highest number of atmospheric pressure trough were 2:00,15:00 and 16:00,accounting for 27.4%.The peak-to-trough transition time was mainly concentrated around 6 h,and the diurnal variation curve of atmospheric pressure was mainly bimodal.The atmospheric pressure change rate was mostly concentrated in 10–50 Pa/h.It was determined that the distance that the gas sampling pipe was pre-laid into the inner side of the closed wall should be greater than 44.4 m,and the CO concentration and atmospheric pressure in the closed goaf were both periodic and negative with atmospheric pressure.The research results have important guiding signifcance for the monitoring,early warning and environmental protection of the goaf.
基金We gratefully acknowledge the State Key Research Development Program of China(Grant No.2016YFC0501106)and the National Natural Science Foundation of China(Project 51574253).
文摘Coal is the vital resource of energy in China,but abandoned coal ash and gangue lead to the degradation of vegetation cover and reduce soil quality.Both arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB) play a key role in biogeochemical cycle such as soil organic matter decomposition,nutrition release,and energy flow.To improve and reclamation the soil quality and ecological efficiency of the coal mining waste,we investigated the effects of an AMF strain (Glomus mosseae) and a PSB strain (Pantoesstewarti) on phytate mineralization and subsequent transfer to the host plant (Medicago sativa L.) using a two-compartment microcosm with a central 30 mm nylon mesh barrier.The results showed that significantly higher available P (AP),above ground biomass (AGB) and underground biomass (UGB) were in combined inoculation of AMF-PSB than other treatments in root and hyphae compartment.The microbial inoculum of the AMF or PSB had a significant influence on soil acid phosphatase activities (ACP).AMF-PSB enhanced phytate mineralization,improved plant biomass.AP and ACP positively influenced the AGB and UGB.AMF-PSB could be used as bioinoculant to enhance sustainable production of the plant in abandoned solid waste of coal mine.
基金the National Natural Science Foundation of China(No.41977159).
文摘The discharge of acid mine drainage from abandoned high sulfur(S)coal mines has caused serious pollution in the Shandi River,Yangquan,Shanxi Province.To determine the impact of long-term acid mine drainage on the microorganisms in the river,we collected river sediments from a polluted tributary(Group P)and the mainstream of Shandi River(Group R)to study the bacterial diversity and community composition.The results showed that the tributary was seriously polluted by acid drainage from abandoned coal mines,with the pH value of the sediment being<2.5,resulting in the low bacterial richness and diversity of the tributary samples.Acidophillic Fe-and S-metabolizing bacteria,such as Metallibacterium,Acidiphilium,and Acidithiobacillus,were the dominant genera in Group P samples,while the Group R was dominated by the neutral anaerobic iron-reducing bacteria Geothrix and Geobacter.Results of principal co-ordinates analysis(PCoA)revealed that the bacterial communities are significantly different between groups P and R,and the significant different species were mainly attributed to phylum Proteobacteria,Actinobacteria,and Acidobacteria.The distribution of the microbial community is mainly influenced by pH,and the Fe and Cd concentrations.Metallicactrium,the dominant genus,is negatively correlated with pH(R^(2)=-0.95)and positively correlated with Fe(R^(2)=0.99),while Geothrix and Geobacter,are mainly affected by the heavy metals.This study determined the impact of river pollution caused by abandoned coal mine drainage,especially on the microbial diversity and community composition within the river sediment.
基金The authors wish to thank the financial support provided by the National Natural Science Foundation of China(41977159).
文摘The seasonal and spatial changes in the chemical composition of the water in abandoned mine drainages and rivers in Yudong River area in the years of 2017-2018 were analyzed.The effects of mine water drainage on the seasonality and physicochemical properties of the river water after mine closure were evaluated,and the feasibility of irrigation using river water and the degree of pollution to farmland were assessed using the Water Quality Standard for Farmland Irrigation.The results show that the mine water has low pH value(<3.5-4)and high levels of total hardness,SO_(4)^(2−),Fe,Al,and Zn.In addition,the pH of the mine water is negatively correlated with the presence of other metal ions.The correlation coefficient between the chemical oxygen demand(COD)and Fe reached 0.989.While the pollution levels of Pinglu and Baishui rivers were low,the confluence region of the two rivers was seriously polluted.However,only the levels of Fe and Cd slightly exceeded the Surface Water Environmental Quality Standard after the confluence of Yudong and Chongan rivers.Overall,the heavy pollution type of the confluent river is consistent with mine water pollution.The water quality is slightly better in the dry season compared than in the high-water period.Sulfate and Fe content decreased by 39 and 16 mg/L,respectively,and Cd content decreased two-fold.Despite these findings,this study shows that from 2017 to 2018,the pH and Cd content of the rivers at the confluence exceeded the irrigation limit and the water quality continued to deteriorate,which may pose a soil contamination risk.Long-term use of the river for irrigation water may cause toxic elements such as Cd,Fe,Mn,SO_(4)^(2−),Al,and F-to enter the food chain,thereby endangering the life and health of villagers in Yudong River area.
基金Research Funds for Yue Qi Young Scholars(No.2018QN11)the Fundamental Research Funds for the Central Universities(2009QG09).
文摘With the increasingly prominent environmental problems of abandoned coal mines,this paper discussed the significance of environmental vulnerability assessment of abandoned coal mines.Environmental vulnerability assessment is essentially an assessment of environmental quality.At present,the research object of environmental impact assessment method and program of mine is mostly single factor.However,the impact of abandoned coal mine on the environment is multifaceted,which was summarized into nine prominent common problems.Based on these nine factors,the environmental vulnerability assessment model of abandoned coal mine based on multifactor evaluation was established by using the analytic hierarchy process(AHP)method,the ranking criteria of nine factor indexes was proposed,the evaluation process was established,and the evaluation index system of environmental vulnerability of abandoned coal mines was established.The environmental vulnerability assessment method of abandoned coal mines has universal applicability,which can provide the basis for the government and enterprises to carry out treatment and planning of abandoned coal mine and promote the optimization of governance effect.
文摘Lipovtsy coal field mine №4 processed north-western reserves of Lipovtsy field in Primorski Krai (Russia). In 1997, the mine was declared unprofitable and was abandoned by natural flooding with no arrangement of mine water discharge and in 2005 it was fully flooded. The main sources of pollution in the studied area are spoil heaps (mine wastes), underspoil filtering waters and mine waters which are being discharged on the surface after finishing of “hydraulic funnel” artificial support. The study of technogenic landscape of abandoned mine industrial area showed that its morphologic form is dominated by spoil heaps. Soils located near mine waste body differ from benchmark soils by chemical properties and size distribution. The influence of active hydrochemical mine and drainage water flows is the reason of the above-mentioned variation in soil properties. Results showed that, there exist a high correlation ratios between chemical composition of mine waters and water extracts from soil: Between the alkalinity of mine waters and electrical conductivity of soil water extracts (r = 0.73), between mine water iron content and pH of soil water extract (r = −0.56), between the solid residue of mine waters and electrical conductivity of soil water extracts (r = 0.72), between the mine waters calcium content and electrical conductivity of soil water extracts (r = −0.75), between the alkalinity of mine waters and silicon dioxide content of soil water extracts (r = 0.61), between the mineralization of mine waters and chrome content of soil water extracts (r = 0.73).
基金financial support from the National Natural Science Foundation of China(Nos.51804111,51974117,51904102,and 52074117)Natural Science Foundation of Hunan Province(No.2020JJ5194)the Postgraduate Scientific Research Innovation Project of Hunan Province(No.CX20200991)。
文摘In multi-seam mining,the interlayer rock strata between the upper coal seam(UCS)and the lower coal seam(LCS)appear damage and strength weakening after mining the UCS.Ground stability control of the gob-side entry retaining(GER)under the gob with close distance coal seams(CDCS)is faced with difficulties due to little attention to GER under this condition.This paper focuses on surrounding rock stability control and technical parameters design for GER under the gob with CDCS.The floor rock strata damage characteristics after mining the UCS is first evaluated and the damage factor of the interlayer rock strata below the UCS is also determined.Then,a structural mechanics model of GER surrounding rock is set up to obtain the main design parameters of the side-roadway backfill body(SBB)including the maximum and minimum SBB width calculation formula.The optimal SBB width and the water-to-cement ratio of high water quick-setting material(HWQM)to construct the SBB are determined as 1.2 m and 1.5:1.0,respectively.Finally,engineering trial tests of GER are successfully carried out at#5210 track transportation roadway of Xingwu Colliery.Research results can guide GER design under similar mining and geological conditions.
基金The research is supported by National Key R&D Program of China(No.2017YFC060300204)National Natural Science Foundation of China(No.52074293)+2 种基金Hebei Province Natural Science Foundation of China(No.E2020402041)Yue Qi Young Scholar Project,CUMTB and Yue Qi Distinguished Scholar Project(No.800015Z1138)China University of Mining&Technology,Beijing.
文摘In the Kaiping Coal field,mining of five coal seams,located within 80 m in the Kailuan Group,#5,#7,#8,#9 and#12 coal seam,is difficult due to small interburden thickness,concentrated stress distributions,high coal seam metamorphism,and complex geological conditions.By using the ZTR12 geological penetration radar(GPR)survey combined with borehole observations,the overburden caving due to mining of the five coals seams was measured.The development characteristics of full-cover rock fractures after mining were obtained from the GPR scan,which provides a measurement basis for the control of rock strata in close multiple coal seam mining.For the first time,it was found that the overburden caving pattern shows a periodic triangular caved characteristic.Furthermore,it is proposed that an upright triangular collapsed pile masonry and an inverted triangular with larger fragments piled up alternately appear in the lower gob.The research results show that the roof structure formed in the gob area can support the key overlying strata,which is beneficial to ensure the integrity and stability of the upper coal seams in multiple-seam mining of close coal seams.
基金Project(2014QNA50)supported by Fundamental Research Funds for the Central UniversitiesChina+1 种基金Project(51404248)supported by National Natural Science Foundation of the Youth Science Foundation of ChinaProject(PAPD)supported by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘A roadway within ultra-close multiple-seams(RUCMSs) is one of the most difficult supported coal roadways to deal with in underground coal mines. This is usually due to the unknown stress distributions, improper roadway layout, and unreasonable support parameters. In order to solve this support problem and effectively save RUCMSs from frequent and abrupt disasters(such as serious deformation of the surrounding rock, roof cave ins, and coal side collapse), a comprehensive method is adopted here which includes theoretical analysis, numerical simulation, and field monitoring. A mechanical model was constructed to determine the stress distribution in the coal pillar after two sides of a longwall panel had been mined. Based on this model, the horizontal, vertical, and tangential stress equations for the plane below the floor of the upper-left coal pillar were deduced. In addition, a typical coal mine(the Jinggonger colliery, located in Shuozhou city, Shanxi province, China) with an average distance between its 9# and 11# coal seams of less than 8.0 was chosen to conduct research on the proper layout and reasonable support required for a typical coal roadway located within coal seam 11#. Using FLAC3D(Fast Lagrangian Analysis of Continua in 3-Dimensions) numerical software, eight schemes were designed with different horizontal distances(d) between the center lines of the coal pillar and the roadway in the lower coal seam(RLCS). The simulations and detailed analysis indicate that the proper distances required are between 22.5 and 27.5 m. A total of 20 simulation schemes were used to investigate the factors influencing the support provided by the key bolts(bolt length, spacing, distance between two rows, installation angle, and pre-tightening force). The results were analyzed and used to determine reasonable values for the support parameters. Field results show that the stability and strength of the RLCS can be effectively safeguarded using a combination of researched stress distribution characteristics, proper layout of the RLCS, and correct support parameters.
文摘The paper presents the mining method for the close quarter coal seams with thin rock sheet, that is mining the low coal seam, recovering the top coal seam after putting down the roof rock of the low coal seam. Practice has proved that in recovering the top coal outside the face width after the rock between seams falls naturally or is demolished, the technology is simple, easy to operate and does not make a great demand for technical equipment. In the process of recovering the top coal, the low seam support could not be affected seriously, and two seams mining could be coordinated. Compared with the individual mining method, this mining method can produce a better economic benefit.
文摘面向“30·60”双碳目标,矿区能源利用方式的绿色、经济、高效转型成为我国能源革命的迫切需求。西部矿区拥有丰富的可再生能源资源禀赋,但仍面临着可再生能源就地消纳困难,电力设备投资成本高、利用率低以及外送输电通道有限的困难。为提升矿区用能清洁化程度,提升矿区能源供给的稳定性与可靠性,增强矿区对外部电网的支撑能力,提出全清洁能源下的高品质矿区能源系统(High-quality Coal Mine Energy System,HCMES)及其配置优化方法。首先,考虑西部矿山综合能源系统的负荷特点与伴生能源利用,结合可再生能源发电与废弃矿井抽水蓄能,构建全清洁能源下的HCMES架构。其次,考虑到矿区生产全流程负荷的需求响应能力,考虑系统的能量平衡约束,提出全清洁能源下的高品质矿区能源系统优化配置模型。最后,以系统年平均综合成本最小化为目标,将原问题转化为混合整数线性规划模型,求解生成高品质矿区能源系统优化配置方案。以我国西部某年产煤量1200万t的矿区实际数据为实例,验证所提模型与方法的有效性,并分析可再生能源出力与生产负荷需求不确定性对系统优化配置结果的影响。算例仿真设置了4种矿区能源系统配置方式:不配置储能、配置抽水蓄能、配置电化学储能、配置抽水蓄能(不外购电能)。结果表明,所提出的HCMES相较于其他配置方式可减少电气一次设备投资11.11%,相较于方式3可降低年平均综合成本7.91%,且最多可减少矿区生产用能总二氧化碳排放量91.17%。