With the westward shift of the focus of coal mining,the Jurassic coalfield in the northern Ordos Basin has be-come an important energy security base in China.However,high-intensity mining of coal resources may cause great dam-age to the ecological environment(especially groundwater resources)in the region.To understand the destructive laws of coal mining on the groundwater system,it is necessary to clarify the hydrogeological conditions such as the replenishment,drainage,and renewal capacity of groundwater in coal mining areas.Based on the topography,coal seam burial,and overlying rock structure of the study area,combined with the impact of coal mining disturbance on the roof aquifer,radio-active isotope tritium in groundwater at different burial depths was collected and detected.The historical data of precipita-tion tritium concentration in the study area were restored using logarithmic interpolation method and other methods,and the groundwater renewal rate in the study area was calculated using the updated rate model proposed by Shalle et al.The research results indicate that the groundwater in the shallow buried area mainly comes from Quaternary groundwater and Jurassic groundwater,with a tritium concentration value of 8.60-16.20 TU,which is close to the tritium concentration in atmospheric rainfall and surface water.The annual average renewal rate of groundwater in the shallow buried area is between 0.47％/a and 3.89％/a,reflecting that the groundwater in the shallow buried area is mainly supplied by atmospher-ic rainfall and surface water,with abundant replenishment,short transport path,fast renewal rate,and strong capacity.The groundwater in the medium deep buried area comes from Yan'an Formation and Zhiluo Formation of the Jurassic system,with a tritium concentration value of 7.53-15.55 TU,which is similar to the groundwater in the shallow buried area.The tritium concentration at Z1 and Z2 points are higher than most of the groundwater in the shallow buried area.The calcu-lated groundwater renewal rate is between 0.35％/a and 3.28％/a,which is close to the groundwater in the shallow buried area.This is mainly due to the hydrogeological structure developed in the Yushen medium deep buried coalfield area,where the Jurassic groundwater renewal rate is faster.The water in the deep buried area comes from Yan'an Formation and Zhiluo Formation of Cretaceous and Jurassic periods,with tritium concentration values at or below 12.20 TU,all lower than the tritium values in the medium deep buried area(except for point N4).The groundwater renewal rate in the deep buried area is generally less than 0.05％/a,mainly due to the large burial depth of the groundwater in the deep buried area.In addition,Jurassic strata have a sandstone mudstone interbedded structure,and the groundwater recharge process is long,with slow infiltration recharge,resulting in a much lower renewal rate of the water in the deep buried area than that in the medium deep buried area.The tritium concentration and renewal rate of groundwater in space decrease with the in-crease of water level burial depth.In areas where the coal seam burial depth is large and the direct water filling aquifer groundwater renewal rate is small within the water conducting fracture zone,the impact of coal mining on the groundwa-ter resources of the overlying Quaternary and Cretaceous aquifers is relatively small,and it belongs to the hydrogeological guarantee area that meets the requirements of green coal mining.

Mining activities affect the metal concentrations in mine water (MW). However, mechanism of metals enrichment in MW under mining activities is not well understood. This study investigates the relationships between Fe, Mn, and Zn concentrations in MW and its recharge sources, and the geochemical composition of surrounding rock and coal. Water-coal/rock interaction experiments were conducted to study the mechanisms of metal dissolution, considering both the metal occurrence forms and types of dissolved organic matter (DOM). Results indicate that coal mining significantly disturbs the original geological structure and environment, facilitating groundwater flow from Aquifer III into mining areas. Prolonged interaction between groundwater and fractured coal/rock significantly enhanced Fe, Mn, and Zn leaching. Fe and Zn were elevated 9.88-fold and 3.44-fold, respectively, compared to Aquifer III (0.93 and 1.08 mg/L), while Mn changed slightly compared with Aquifer III (0.17 mg/L). Fe exhibited the highest leachability, primarily originating from exchangeable and carbonate bounded forms during water-coal/rock interaction. Concurrently, DOM dissolution from coal released humic acids, promoting desorption of metals. Metal release during water-coal interaction follows a peak function (R-2 > 0.83). While metal release during water-rock interaction fits with an exponential function (R-2 > 0.94). Although metal release patterns differ between water-coal and water-rock interaction, both processes collectively govern metal concentration in MW. This study demonstrates metal occurrence forms and DOM participation influence metal enrichment in MW during water-coal/rock interaction following coal mining disturbance.

The region where Inner Mongolia and Shaanxi converge is pivotal for the underpinning of national energy se-curity and is also central to the ecological conservation and sustainable development of the Yellow River Basin.Intensive coal extraction in this zone potentially poses a substantial threat to ecological conservation,notably by undermining the in-tegrity of the shallow Quaternary groundwater environment.Accurate assessment of the leakage from various aquifers within the overburden is a complex task,thereby complicating the development of scientifically sound and targeted strategies for water conservation during coal mining.Our research leverages the principle of isotopic mass balance,follow-ing the analysis of environmental isotopes(Deuterium and Oxygen-18)present in the groundwater of the aforementioned border region,to quantify the relative contributions of different mine water sources.Findings indicate that the isotopic sig-natures in the aquifer waters are influenced by a multitude of factors including topography,stratigraphic configuration,and the nature of groundwater storage.The direct sources of groundwater in the Quaternary aquifer of the study area are atmo-spheric precipitation and surface water,characterized by rapid circulation and renewal,replenished by modern water with tritium-rich features.The deuterium(D)and oxygen-18(18O)values in the groundwater are close to those of atmospheric precipitation and surface water.In the deep-buried Cretaceous aquifer,the hydraulic connection with the Quaternary is tight,and the cycle and renewal process is prolonged,resulting in a decrease in environmental isotope values.The deuteri-um values in the Cretaceous groundwater range from-80.2‰ to-75.6‰,and the oxygen-18 values range from-10.6‰ to-8.7‰.The groundwater in the Jurassic aquifer,which is controlled by vertical recharge,exhibits a slower cycle and re-newal rate,with gradually decreasing δD and δ18O values.The shallow and moderately deep-buried strata have a long de-positional history and better cementation,affected by later tectonic movements,and are in direct contact with the Quatern-ary or Neogene,receiving replenishment from Quaternary groundwater,thus having relatively higher δD and δ18O values.In contrast,the Jurassic strata in the deep-buried area,with its substantial thickness and overlying thick layers of Quatern-ary and Cretaceous strata,have poor groundwater replenishment,a long groundwater flow path,and are relatively closed and stagnant,resulting in relatively lower δD and δ18O values.The application of the D-value,in conjunction with the bin-ary mixing model,facilitates the quantitative assessment of the contribution of Quaternary waters in shallow-buried coal mine waters.In the case of the SGT and HLG coal mines,the proportion of Quaternary waters is typically less than 20％.In contrast,the Quaternary water content in the BLT and LSJ coal mines varies between 28.0％and 57.0％.Notably,the Quaternary water proportion in the YBJ coal mine approaches 80％,indicating a significantly higher contribution.For the middle and deep-buried coal mine waters,the Quaternary water content is generally less than 20％.However,it is note-worthy that in the HLW and SS coal mines,which have been developed earlier and feature'skylights'of the Puding Form-ation red soil layer in the roof,the Quaternary water content has reached 37.05％and 26.24％,respectively.This suggests that under specific geological conditions,the proportion of Quaternary waters may be substantially elevated.In the deep-buried mine waters,the contribution of Cretaceous water is approximately around 30％.IsoSource modeling has calcu-lated that the contribution rate of Quaternary water ranges from 7.6％to 9.3％,the contribution rate of Cretaceous water is between 12.0％and 17.1％,and the contribution rate of the Upper Jurassic water is from 74.9％to 80.4％.Moreover,the contributions of various sources to the mine waters are similar across different mining areas.By using the D content value in groundwater and a binary mixed model,it was calculated that the proportion of Quaternary water in shallow buried mine water was less than 20％for SGT and HLG coal mines,28.0％to 57.0％for BLT and LSJ coal mines,and nearly 80％for YBJ coal mines;The proportion of Quaternary water in the mine water in the middle and deep buried areas was generally less than 20％.The proportion of Quaternary water in HLW and SS coal mines,which were developed earlier and had a"skylight"in the red soil layer of the Baode Formation on the roof,reached 37.05％and 26.24％respectively.The proportion of Cretaceous water in deep buried mine water was about 30％.The IsoSource model calculates that the contribution rates of Quaternary water were between 7.6％and 9.3％,Cretaceous water was between 12.0％and 17.1％,and the contribution rates of upper Jurassic water were between 74.9％and 80.4％.The contribution rates of various sources of mine water in different mining areas were similar.This study accurately identified the proportion of water sources in various aquifers of mine water,which was of great significance for ecological environment protection and green and sustainable development of coal resources in the contiguous area of Inner Mongolia and Shaanxi.Accurately identify-ing the source proportions of water from various aquifers in mine water is of significant importance for the conservation of water resources and ecological protection in the coal mining areas bordering Inner Mongolia and Shaanxi.This study aims to provide a precise delineation of these proportions,thereby contributing to sustainable mining practices and the preserva-tion of the ecological environment in the region.

The characteristics of Chinese energy endowment determine that coal is the main energy source for long-term stability in the future. With the depletion of coal resources in the eastern region, the northwest coal rich area has become the core area for coal resource development. In the past 30 years, continuous and in-depth geological and hydrogeological exploration and underground mining in western mining areas had revealed significant differences in the geological structure and hydrogeological conditions of different mining areas/mines, resulting in significant differences in mine water inflow. Based on the analysis of the water inflow of major coal bases in western China, combined with the geological and hydrogeological conditions of the mining area, a water filling mode of the roof aquifer under mining disturbance is proposed. The Inner Mongolia East Coal Base mainly mined Cretaceous coal resources. Poor diagenesis of the coal seams and their roof strata and high porosity of the aquifers provided good conditions for the storage and transportation of groundwater. The Inner Mongolia East Base had the highest average water yield coefficient (2.09 m3/t) and the highest total water inflow (5.54×108 m3/a). Other coal bases mainly mined Jurassic coal resources. The average water yield coefficients were around 0.60 m3/t (except for the Shaanxi part of Huanglong Base, which had an average water yield coefficient of 1.85 m3/t). The DM, ZNH, YBS and other coal mines in the Mengdong Base were adjacent to large rivers, with water inflows exceeding 4000 m3/h. The JJ coal mine in the northern Shaanxi base had shallow coal seam burial, large thickness of the Quaternary aeolian sand layer, and strong water abundance. The water conducting fracture zone of coal mining communicated with the Quaternary aquifer, and the water inflow of the mine was more than 3000 m3/h, even exceeding 6000 m3/h during peak periods. The NTT, XW and other coal mines in the northern Shaanxi base were affected by the burnt rock aquifers, with a water inflow of about 1000 m3/h. The surface of the border area between Inner Mongolia and Shaanxi was the Maowusu Desert. The thickness of the Quaternary and Cretaceous strata was over 400 m, which continuously replenished the bedrock aquifer and formed a multi-layer superimposed composite aquifer structure. The water inflows of most mines were more than 1500 m3/h. The rivers in the Binchang mining area cuted through the Cretaceous bedrock, and the thickness of the Cretaceous aquifer was large (500–700 m), forming a “sponge type” thick aquifers. The development of water conducting fracture zones connected the middle and lower sections of the Cretaceous aquifer, and the water inflow of GJP coal mines in the area exceeded 7000 m3/h. The coal seam fractures in the northern area of Yuheng were relatively developed, with a wide range of coal seam aquifers. The static reserves of coal seam water were large, and the mine water inflow was more than 1000 m3/h. The conventional water filling modes of the coal seam roof and floor aquifer was summarized, and three water filling modes were proposed, including the “strong filling type” shallow aquifer water filling modes, the “sponge type” thick aquifer water filling modes, and the coal seam aquifer water filling mode. The study could provide scientific basis for active protection of groundwater resources and coordinated utilization of mine water in western coal bases.

Recently, high levels of fluorine have been detected in mine water, posing a potential risk to human health in light of the comprehensive utilization of mine water. Focusing on the Shendong area, this study aims to reveal the occurrence, spatial distribution, main sources, and health risks associated with fluorine in mine water using Piper diagrams, statistical analysis, SEM–EDS of rocks, and health risk assessment models. A total of 101 samples, including 68 water samples and 32 rock samples, were collected and analyzed. Results show that the average concentration of fluorine in the study area is mostly greater than 1 mg/L, belonging to high-fluorine mine water. Mine water with elevated levels of fluorine is with an abundance of Na+ and a scarcity of Ca2+. The distribution of fluorine content in mine water of Shendong mine varies significantly with the depth of mining depth, resulting in lower fluoride levels in 1# and 2# mine water and higher levels in 3# mine water. The primary cause of elevated fluorine in 3# mine water is attributed to 3# roof groundwater related to the prolonged water–rock process between groundwater and rock formations. Health risk assessments demonstrate that mine waters from Shigetai, Daliuta, and Huojitu pose no health risks to infants, children, males, or females, whereas waters from Halagou, Buertai, Cuncaota, Bulianta, Shangwan, and Wulanmulun present potential hazards. Health risks associated with mine water are closely correlated with its fluorine concentration. To ensure compliance with drinking and living standards, a proposed solution involves coagulation precipitation followed by adsorption to remove fluorine from mine water. This study provides valuable insights into the distribution, sources, risk assessment, and mitigation of fluorine in mine water and groundwater.

Acid mine water (AMD) can cause many environmental and social problems. The high sulfate ion content in AMD is one of the key factors contributing to contamination. Microbial electrolytic cell (MEC) is an electrically mediated microbial electrochemical technology. In explore the mechanism of the effect of MEC on AMD-containing sulfate, the construction of microbial sulfur removal system (MEC-CS) and CS system with SO42− removal rate as the target were discussed. Hash water analyzer (DR2600), ion chromatograph (TIS), and pyrophosphate sequencing were applied to analyze the desulfurization efficiency, the activity of electro-microorganisms on electrodes, and the evolution pattern of intermediate key ion products in both treatment systems. The results show that: The maximum sulfate removal rate in the MEC-CS system was 62.6%, which was 33.9% higher than that of the conventional CS system (28.7%), it indicates that the desulfurization capacity and AMD processing capacity are effectively improved; Sequencing results showed that Desulfovibrio and Desulfobacterium were most enriched in the cathode electrode, this indicates that a certain voltage promotes the activity of sulfate-reducing bacteria and facilitates the desulfurization capacity. In addition, the abundance of various SRBs involved in sulfate reduction was high, and MEC significantly enhanced the hydrogenase activity of SRBs, making them more capable of reduction; MEC-CS has a higher concentration of key intermediate ions (SO42− ions, S2− ions, total iron, etc.) realized in the reaction process and a higher conversion rate compared to the CS system. Electrogenic bacteria in the MEC-CS system were less frequently detected in the CS system. MEC enhances the efficiency of sulphuric acid removal by facilitating electron transfer in the microbial desulphurization process, and the method also enables the removal of heavy metal ions such as iron and the recovery of purer minerals. Thus, it provides a new idea for the industrialization and economization of the bioelectric desulfurization process.

The over-exploitation of groundwater and the deterioration of its quality have heightened the importance of non-traditional water resources, such as mine water. The study of the water’s chemical characteristics and the formation mechanism of high-salinity mine water in semi-arid regions holds significant importance for zero discharge and the resource utilization of mine water in Northwest China. In this study, a total of 38 groundwater and mine water samples were collected to examine the hydrogeochemical characteristics of high-salinity mine water using Piper diagrams and Gibbs diagrams, as well as isotope analyses and ion ratio coefficients. Additionally, the corresponding mine water treatment recommendations were put forward. The results show that the TDS content of groundwater increases with hydrographic depth. The average TDS concentration of Quaternary, Luohe, and Anding groundwater is 336.87, 308.67, and 556.29 mg/L, respectively. However, the TDS concentration of Zhiluo groundwater and mine water is 2768.57 and 3826.40 mg/L, respectively, which belong to high-salinity water. The Quaternary, Luohe, and Anding groundwater hydrochemical type is predominantly HCO3-Ca type, and the Zhiluo groundwater and mine water hydrochemical type is predominantly the SO4-Na type. Furthermore, there is minimal difference observed in δD and δ18O values among these waters. It can be inferred that the Zhiluo Formation in groundwater serves as the primary source of mine water supply, primarily influenced by the processes of concentration caused by evaporation. The high salinity of mine water is closely related to the high salinity of Zhiluo groundwater. The high salinity of groundwater has evolved gradually under the control of the concentration caused by evaporation and rock-weathering processes. The dissolution of salt rock, gypsum, along with other minerals, serves as the material basis for high-salinity groundwater formation. In addition, the evolution of major ions is also affected by cation exchange. The TDS concentration of mine water ranges from 3435.4 mg/L to 4414.3 mg/L, and the combined treatment process of nanofiltration and reverse osmosis can be selected to remove the salt. After treatment, mine water can be used for productive, domestic, and ecological demands.

Excessive fluoride ion (F-) concentrations in mine water affected by the geologic processes and coal mine activity prevent the reusage of it as domestic and production water resources. There are few researches on the accumulation mechanism of fluoride in mine water. In this study, 71 water samples and 39 rock samples were collected from 9 mines of the Inner Shaanxi-Mongolia Contiguous area for chemical analyses and laboratory experiments. Results indicate that the concentration of F- in mine water increased with the gradual increase of the coal mining depth. The average concentration of F- in no.3-1 coal mine water is higher than that in no.2-2 coal mine water. And concentrations of F- exceed the China national standard for drinking water quality (upper limit of 1 mg/L), which is closely related to fluoride in the no.3-1 coal roof groundwater and water-rock interaction in the goaf. The main hydrogeochemical processes include mineral dissolution (fluorapatite and hornblende), desorption of exchangeable F- from clay minerals (mica, illite, kaolinite and chlorite) and cation exchange between Ca2+ and Na+. Furthermore, long-term further water-rock interactions result in F- accu mulationin mine water. Alkaline environments, decreased particle size of rock, and increased temperature all favor release of F- from clay mineral surface into mine water. Finally, conceptual model of high-fluoride mine water was first proposed, and the formation of high-fluoride mine water can be summed as two stages including water-rock interaction in groundwater and secondary water-rock interaction in goaf. This study helps to improve our understanding of genesis of high-fluoride mine water and our capability of predicting the future concentration, which may provide foundation for manage and utilization of mine water.

With the improvement of coal-mining mechanizations and the intensification of human activities, the organic matter pollution of mine water is becoming severe. In this study, the chemical compositions of the influents and effluents from 15 mine water treatment stations in the mining area bordering Mongolia and Shaanxi were measured. The occurrence of DOM (dissolved organic matter) in the effluent from the mine water treatment stations in this area was determined by the EEM (excitation emission matrix), combined with the PARAFAC (parallel factor analysis) method. The DOM removal from the mine water treatment station in the Caojiatan coal mine is specifically discussed here, although trends are similar across the 15 mines. The treatment capacity of this treatment process for different types of pollutants is also evaluated, and a mine water treatment process suitable for the current coal-mining mode is suggested. The results show that the DOM of the mine water treatment stations in this area mainly has four components: a fulvic-acid-like substance (C1/C3), a protein tryptophan-like substance (C2), and a protein tyrosine-like substance (C4). The coagulation, filtration, and disinfection process has a removal efficiency of more than 90% for the protein-like tryptophan components, COD (chemical oxygen demand), and NO2−, and an efficiency of ~50% for TOC (total organic carbon), <30% for Cu2+ and F−, and almost no removal effect for protein-like tyrosine components, EC (electrical conductivity), TDS (total dissolved solids), and NH4+. These conclusions show that aliphatic hydrocarbons, such as alkanes and cycloalkanes, in mine water are removed by the treatment process, whereas macromolecular aromatic hydrocarbons and other groups are not removed by the treatment process. Based on this, an ozone-demulsification process for the special removal of protein tyrosine-like pollutants in mine water is proposed. This conclusion can provide theoretical support for research on the source and fate of the carbon trajectory in the water-cycle process and provides technical guidance for the removal of DOM from mine water.

蒙陕深埋矿区属于新开发矿区,煤炭开采扰动下水文地质特征仍不清楚,基建和生产过程中发生了多种类型的水害问题,其中工作面回采过程中和回采结束后的涌水变化特征研究处于空白,给井下排水系统设置和防治水工作开展增加了难度.为查清工作面回采前后的全生命周期涌水量演化规律,开展顶板含水层分布、导水裂隙带发育、涌水量变化等方面的实测研究.结果表明:煤层顶板地层均属于河流/河湖相沉积,空间上呈含隔水层互层状展布,隔水层的主要岩性为泥岩、砂质泥岩;受控于鄂尔多斯盆地伊陕斜坡的单斜构造,含煤地层高程在蒙陕接壤区最低,其顶板侏罗纪煤系含水层属于区域性地下水滞流区.煤层顶板地层在中生代沉积旋回作用下,发育了3层直接充水含水层,其中直罗组七里镇砂岩(Ⅰ号含水层)距离3-1煤层顶板77.4～109.4 m,呈富水强、水压高的特点;导水裂隙带实测高度为103.4 m,裂采比18.8,工作面回采过程中导水裂隙带将发育至Ⅰ号含水层.工作面回采前期,随着导水裂隙带向上发育沟通不同含水层,采空区涌水量呈阶段性增加,工作面回采至300 m左右,采空区涌水出现第一个峰值;工作面回采中后期,导水裂隙带持续周期性发育,导致顶板含水层破坏范围不断扩大,采空区涌水量仍呈台阶式增加;工作面回采结束前后,采空区范围内顶板导水裂隙带发育最强烈、范围最大,出现采空区涌水量最高值;工作面回采结束后,在其顶板隔水层中泥质组分的自弥合作用下,隔水层逐渐再造,导水裂隙宽度变窄、数量变少,采空区涌水量"缓坡式"衰减(每小时几十立方米以内).对工作面涌水量实现全生命周期演化规律掌握,可以为蒙陕深埋矿区井下工作面防治水工作提供科学依据.

Abstract In order to understand the evolution law of groundwater quality during the artificial recharge process with mine water, the effluent from the mine water treatment plant of the Mindong No. 1 Mine was selected to artificially recharge the Quaternary aquifer of the study area. In this experiment, the spatial evolution of the groundwater quality of some wells around the recharge well was monitored during the artificial recharge process with reclaimed mine water. The factor analysis method was used to reveal the evolution law of groundwater quality during the recharge process. Although the reclaimed mine water met the standards for artificial recharge, the results showed that pH value as well as Cl−, TDS, NO3−, and F− concentrations in the reclaimed water were higher than those observed in the Quaternary aquifer, presenting a potential risk to groundwater quality. On the other hand, four organic components were identified in the groundwater after the artificial recharge, including fulvic-like acids (Ex/Em = 280/440, Ex/Em = 250/440) as the main component. Indeed, most of these components were caused by terrestrial origin and soil migration. In addition, the reclaimed mine water contained protein-like tryptophan (Ex/Em = 300/340), which was mainly derived from the discharge of point sources. The total fluorescence intensity of organic pollutants in the different wells tended to be uniform with the recharge time. However, if external pollution is introduced, it may significantly affect the types of organic pollutants and diffuse rapidly within 24 hours. Therefore, it is necessary to control effectively the concentration of trace organic matter in the influent water to ensure the safety of the artificial recharge with mine water.

Abstract In order to find out the status of organic pollutants in coal mine area of Ordos Basin in northwest China, we used an excitation emission matrix combined with parallel factor analysis to study the compositional characteristics and fluorescence intensity of dissolved organic matter (DOM) in mine water. In this way, we found that the DOM in the Mongolia-Shaanxi border mining area of Ordos Basin has four main components: two that resemble fulvic acid (C1/C3), a protein-like tryptophan substance (C2), and a protein-like tyrosine substance (C4). The fluorescence intensity of the fulvic acid-like component increased from 334.73 a.u to 440.33 a.u after treatment, and the fluorescence intensity of the protein-like tyrosine-component decreased from 330.18 a.u to 295.78 a.u. And then we investigated the removal efficiency of DOM and other pollution in the Caojiatan mine water treatment plant’s coagulation - filter – ultrafiltration process. In this process, the removal efficiency of the protein-like tryptophan components reaches 90%, while that of chemical oxygen demand / NO2− and the total organic carbon is about 50%. The removal efficiency of the Cu2+ and F−is less than 30%, and almost none of the protein-like tyrosine components, electrical conductivity, total dissolved solids, and NH4+. Thus, It’s proved that aliphatic hydrocarbons such as alkanes and cycloalkanes in mine water were removed in the treatment process, whereas macromolecular aromatic hydrocarbons and other groups were not removed. In the end, we put forward the ozone air flotation process, ozone effect makes the water of oxygen functional groups such as carboxyl, hydroxyl content increased, allowing more of the aluminum, iron, magnesium, and calcium ion complexing, precipitation, leading to desorption from the particulate organic matter, reduce the space steric hindrance and electrostatic repulsion, the effect of enhanced coagulation, Promote the condensation of particulate matter by means of adsorption bridge. This provides theoretical support for research on the source and fate of the carbon trajectory in the water cycle in a coal mine area and provides guidance on the removal of DOM from mine water.

煤矿预疏放水属于未污染的地下水,水质优良具有开发成高质水资源的潜力,以煤矿预疏放奥灰水为对象,通过感官指数和健康指数分析法发现水质的感官指数偏低健康指数较高,为解决传统工艺产水水质感官指数和健康指数不能兼顾的问题,采用混合纳滤反渗透系统对传统工艺进行改进,通过对比NE40,NE70和NF270三种纳滤膜筛选出一级和二级纳滤膜,利用一级和二级纳滤系统分别提高水质的感官指数和健康指数,利用反渗透产水的稀释作用控制水体的溶解性总固体(TDS)在合理区间,混合脱盐系统的浓水TDS控制在1 000 mg/L以下,整个系统基于水质离子质量浓度预测公式设计一级纳滤、二级纳滤和反渗透系统的回收率.结果表明:一级纳滤系统选用NF270膜产水水质更优,预测公式显示随着回收率增加产水水质感官指数不断下降健康指数不断上升,一级纳滤采用70％回收率较为适宜,通过对比水质离子质量浓度预测值与实际值,发现预测偏差＜10％;二级纳滤系统选用NE40膜更优,预测公式显示随着二级纳滤系统回收率的增加感官指数和混合产水TDS加速下降,健康指数先匀速增加后急剧减少,浓水TDS先下降后上升,其中反渗透回收率越高变化临界点越前移,当二级纳滤和反渗透系统回收率分别为50％和75％时,产水水质预测值满足健康美味水要求,同时产水预测TDS适宜为224.01 mg/L,浓水TDS控制在标准线以下为987.85 mg/L;经过实测二级纳滤系统的浓水水质并利用盐平衡得出二级纳滤和反渗透系统回收率分别为50％和75％时的真实混合产水水质,其中感官指数为2.23,健康指数为8.88,TDS为238.4 mg/L,与预测产水水质结果接近,产水水质相比原水明显提升;经济分析显示混合脱盐系统相比于传统工艺运行成本只增加了 7％,无机结垢风险小,同时增加了产水水质的附加值,因此该系统具有潜在的经济效益;工艺适用性分析发现系统具有应对不同原水水质的应用潜力.

为了研究适宜于季节性水质波动条件下矿井水处理的最优实验条件,提出面向生态灌溉的矿井水处理方法,进一步实现露天矿区矿井水资源化利用.以内蒙古某露天煤矿冬、夏两季矿井水为研究对象,选取新型成核剂硅藻土与传统助凝剂阳离子型聚丙烯酰胺(CPAM)、混凝剂聚合氯化铝(PAC)联合投加,对其进行强化混凝处理.结果表明:PAC单独投加条件下,随着PAC投加量的增加,出水TDS逐渐升高,HCO3-浓度逐渐降低;200 mg/L PAC+CPAM联合投加方式下,投加4 mg/L CPAM时冬、夏两季矿井水出水浊度取得最低值0.46、1.04 NTU,浊度去除率高达99.51％、99.71％.CPAM投加量的增加对总溶解固体(TDS)没有显著的影响,对HCO3-浓度影响很小或没有影响,去除效果不明显.矾花形成快速,时间明显短于PAC单独投加与200 mg/L PAC+硅藻土联合投加,此外,随着CPAM投加量的递增,矾花形成时间呈现依次变短的趋势;200 mg/L PAC+硅藻土联合投加方式下,投加400 mg/L硅藻土时冬、夏两季矿井水浊度分别为6.01、8.25 NTU,达到《城市污水再生利用绿地灌溉水质》(GB/T 25499—2010)限制性绿地的限值要求,浊度去除率达93.58％、97.67％,TDS、HCO3-浓度变化基本不受硅藻土投加量的影响.

AbstractThis paper adopted organic components, environmental isotopes, and organic components to study water quality comprehensively, in order to distinguish the differences of hydrogeochemical characteristics between coal measure strata and aquifers on the roof of deeply buried mining areas in Inner Mongolia-Shaanxi, China. The results show that the deeply buried mining area in Inner Mongolia-Shaanxi belongs to Mu Us Desert, and the surface is covered by aeolian sand, with excellent precipitation infiltration capacity. Salinity of surface water and Quaternary water<500 mg/L, the main cation is Ca2+, and the main anion is HCO3-, which belongs to HCO3-Ca·Mg type water. The Cretaceous Zhidan Formation is in unconformable contact with the Quaternary and constitutes a unified water-bearing complex on the whole, which makes Zhidan Formation have a better supply water source, and its inorganic water quality characteristics are close to the Quaternary water. The deep aquifer is affected by the Anding Formation relative impermeable layer and has weak recharge runoff condition. The salinity of Jurassic water is generally >3500 mg/L due to long-term water-rock action. The main cation is Na+, and the main anion is SO42-, which belongs to SO4-Na type water. According to the analysis of hydrochemical characteristics, there is no direct hydraulic connection between Luohe Formation and Zhiluo Formation. The characteristics of environmental isotopes show that the rainwater, surface water, and Quaternary water in the study area belong to the modern groundwater, while Zhidan Formation water is between the modern groundwater and the ancient water. The values of δD and δ18O in the deep Zhiluo Formation and Yan’an Formation are low, and the groundwater falls below the rainwater line of Ordos Basin with a deep circulation depth. Before mining, the groundwater is in a stagnant state with good closed conditions. Qualitative and quantitative signatures of various organic components in water are on the basis of organic geochemistry and hydrogeology, in order to facilitate the study of the quantity, composition, and distribution patterns of organic substances in groundwater and their role in geological, geochemical, and other processes. By testing the organic matter of dissolved organic matter (DOM) in each aquifer, the organic water chemistry characteristics of each aquifer in the Taokutu well field can be established. The content of dissolved organic matter (TOC and UV254) in groundwater decreases gradually with the increase of aquifer depth. Fluorescence peaks in Area I and Area III mainly appeared in surface water and Quaternary water, and DOM sources were more abundant in surface water. The fluorescence peak in Area I also appears in the water of Zhidan Formation, Zhiluo Formation, and Yan’an Formation, and the fluorescence peak between Area I and Area II is a symbol. The fluorescence peak intensity of Cretaceous → Zhiluo Formation in Area V area has an increasing trend, indicating that there are humus-like DOM from other sources in the deep Zhiluo Formation aquifer. In general, the comprehensive analysis of hydrochemical characteristics by various means can well distinguish the differences of hydrogeochemical characteristics among aquifers, which provides a scientific basis for the rapid and accurate discrimination of water situation and disaster in coal mines and the safe production.

利用矿井水进行生态灌溉,可实现煤炭开采、矿井水资源利用及矿区生态修复相互协调发展,矿井水含多种污染物,灌溉前需进行灌溉适宜性评价.以沙地生态脆弱区敏东一矿为研究区,采集地表水、地下水及矿井水水样,分析其水质特征,在此基础上利用盐度危害性(S)、碱危害性(SAR)、可溶性钠含量(SSP)、渗透性指数(PI)与重金属污染指数(HPI)进行多源矿井水资源评价,最后利用极限条件法确定其灌溉适宜性.研究结果表明:研究区17组水样阳离子均以Na+为主,阴离子以HCO3-为主,直接充水水源及矿井水中Fe、Mn、Zn、As、Pb五种重金属质量浓度较高.直接充水水源、采空区、工作面、巷道和水仓水样的SAR(13.29～32.40)和SSP(91.13～97.26),及矿井水样的HPI(150.43～448.81)不符合生态灌溉要求,而所有水样的S(0.76～32.4)和PI(53.33～136.36)均符合生态灌溉要求.根据极限条件法则,研究区间接充水水源可直接进行生态灌溉,而直接充水水源和矿井水受地层矿物溶滤及采煤活动的影响,不可直接用于生态灌溉.

In mining areas, groundwater resources are crucial for providing drinking water, as well as water needed for plant growth and mining. The Yuhengbei mining area is situated in arid and semi-arid areas in Western China. As there are a number of large-scale mining fields in the area, their exploitation may affect both the quality and quantity of groundwater. The hydraulic connection between aquifers directly determines whether deep coal mining activities affect water quality in shallow aquifers. This study investigates the hydrogeochemical characteristics and the solute sources of groundwater (including surface water, Quaternary water, water from Cretaceous and Jurassic coal strata aquifer) in the Yuhengbei mining area. The study uses conventional, multivariate statistical analysis, and dissolved organic matter (DOM) analysis. The results suggest that all water samples were slightly alkaline, while the water from the shallow aquifers (surface water, Quaternary and Cretaceous aquifers) was predominantly of the HCO3-Ca type. Furthermore, the groundwater in the deep Jurassic aquifer was mostly of the SO4-Na type. Major ion and DOM concentrations appeared to decrease with increasing aquifer depth. Moreover, the groundwater circulation is regulated by natural processes. Namely, rock weathering was the main mechanism controlling the chemical constituents of groundwater in the shallow aquifers, while groundwater quality in deep aquifers was mainly governed by the dissolution of evaporation. Water–rock interaction and cation exchange were the main mechanisms controlling the chemical constituents of groundwater. The R-mode HCA revealed that natural processes controlled the chemical composition of groundwater, as well as that the evolution of groundwater is primarily controlled by the nature of the geological structures and the local hydrogeological conditions. The TOC and UV254 results suggest that the coal strata aquifer had a weak hydraulic connection with the overlying aquifers. The DOM was mainly derived from autogenous biological sources. Based on the indicator values, the hydraulic connection between the deep aquifers and the upper shallow aquifers was weak overall. These results show that in this area, although drinking water and irrigation water come predominantly from shallow groundwater, mining activities temporarily have little impact on the quality of shallow groundwater. Better understanding hydrogeochemical characteristics and formation mechanisms will provide a technical basis for local groundwater management and support the sustainable use of water resources.

In order to explore the stable anchoring conditions of coal side under the mining disturbance of soft section coal pillar in Wangcun Coal Mine of Chenghe Mining Area, the distribution model of the anchoring support pressure at the coal pillar side was established, using the strain-softening characteristics of the coal to study the distribution law of anchoring coal side support pressure. The analytical solution for the reinforcement anchorage stress in the coal pillar side was derived with the inelastic state mechanical model. The results show that the deformation angle of the roadway side and roof increases with the roof subsidence due to the mining influence at the adjacent working face, the plastic deformation zone extends to the depth of the coal side, and the increase of anchorage stress can effectively control the roof subsidence and further deterioration of plastic zone. The roadway height and the peak support pressure have a certain influence on the anchorage stress, the required anchorage stress of the coal side rises with the roadway height and the peak support pressure. The required anchorage stress of the coal pillar side decreases as the cohesion between the coal seam and the roof and floor and the anchor length increases. Then, applied the research result to Wangcun coal mine in Chenghe mining area, the design of anchor cable reinforcement support was proposed for the section of coal pillars side that has been anchored and deformed, which achieved great results and effectively controlled the convergence and deformation of the side, providing a safety guarantee for the roadway excavation and mining.

Sinocyclocheilus lingyunensis is endemic to Youjiang River in Guangxi, Southwestern China. In this study, the complete mitochondrial genome of S. lingyunensis was sequenced. It was determined to be 16,572 bases. The overall base composition was 31.9% A, 25.3% T, 26.9% C, 15.9% G with 42.8% GC content. The nucleotide sequence data of 12 heavy-strand protein-coding genes of S. lingyunensis and other 16 Sinocyclocheilus species were used for phylogenetic analyses. Trees constructed using Bayesian inference showed strong support for a topology indicating Sinocyclocheilus species as a monophyletic group.

In order to determine the influence of spheroidization process of Ammonium dinitramide’s hazard grade, the hazardous division of Ammonium dinitramide before and after spheroidization is studied by using hazard classification procedure for combustible and explosive substances and articles standard (WJ20405) and hazard classification method and criterion for combusitible and explosive substances and articles standard (WJ20404). The research results show that spheroidization process can significantly improve the temperature stability of Ammonium dinitramide and significantly reduce friction sensitivity and impact sensitivity of Ammonium dinitramide. So spheroidization process can reduce the hazardous of Ammonium dinitramide and improve the safe character of Ammonium dinitramide.