乌东煤矿地下水水化学特征及其指示

为了研究乌东煤矿煤层顶板含水层之间的水力联系,采用了统计分析、Piper三线图、Gibbs图等方法定性分析了基岩地下水、第四系地下水以及地表水之间的水力联系。利用不同水体的Cl-浓度差异性,计算了相邻含水层之间的水力联系度,定量判别了它们之间的水力联系程度。结果发现,所有地下水样品的pH介于7.1～8之间,都为弱碱性水。随着含水层埋深的加大,地下水TDS逐渐增大,地表水和第四系地下水TDS均低于基岩含水层地下水。基岩地下水、第四系地下水和地表水主要的水化学类型分别为Cl·SO4-Na、HCO3·SO4-Na·Ca、SO4·Cl·HCO3-Na和SO4·Cl·HCO3-Na·Ca。基岩地下水样品受到浓缩作用影响,地表水和第四系地下水受到岩石风化-蒸发影响。同时研究区地下水和地表水中还发生了阳离子反交换作用。第四系地下水和地表水的联系度为0.361,联系程度为中等|第四系和基岩地下水之间的联系度为0.404,联系程度为低。此结果可为后期矿井涌水量预计及防治水工作提供参考依据。     

Evaluating Induced Fractures Between a Large Artificial Lake and an Aquifer-Coal Seam System: A Case Study in Tangshan Coal Mine,China

The hydrogeology of the Tangshan coal mine is extremely complicated. There are at least 20 major faults, with the offset exceeding 50 m. A large artificial lake was created where mining-induced subsidence occurred; it was filled with groundwater pumped from the adjacent aquifers near the coal seams. In addition, there are two nearby rivers that are also believed to have significant groundwater and surface water interactions. Both the river system and the large lake could be a potential threat to a new mining operation in the deep no. 5 coal seam. An in-situ hybrid packer system was designed to measure the thickness of the fracture zone and a 3-D hydrogeological model of the coal seam, associated aquifers, artificial lake, and surface water was established to simulate the groundwater flow field to evaluate the potential impact of induced fractures between the lake and the aquifers and coal seams. The results indicated that the lake has an insignificant impact on the aquifers and coal seams, though it does influence the shallow quaternary aquifer in the study area. Further study is suggested to monitor the groundwater and surface water interactions between the lake and the shallow aquifer system.     

Geochemistry,Hydraulic Connectivity and Quality Appraisal of Multilayered Groundwater in the Hongdunzi Coal Mine,Northwest China

This study assessed the geochemistry and quality of groundwater in the Hongdunzi coal mining area in northwest China and investigated the mechanisms governing its hydrogeochemistry and the hydraulic connectivity between adjacent aquifers. Thirty-four groundwater samples were collected for physicochemical analyses and bivariate analyses were used to investigate groundwater quality evolution. The groundwater in the mine was determined to be neutral to slightly alkaline, with high levels of salinity and hardness; most samples were of SO₄·Cl–Na type. Fluoride and nitrate pollution in the confined aquifers were identified, primarily sourced from coals. Natural geochemical processes, such as mineral dissolution, cation exchange, and groundwater evaporation, largely control groundwater chemistry. Anthropogenic inputs from agricultural and mining activities were also identified in both shallow unconfined aquifers and the deeper confined aquifers, respectively. It was determined that the middle confined aquifer has a high hydraulic connectivity with the lower coal-bearing aquifer due to developed fractures. Careful management of the overlying aquifers is required to avoid mine water inrush geohazards and groundwater quality deterioration. The groundwater in the mining area is generally of poor quality, and is unsuitable for direct human consumption or irrigation. Na⁺, SO₄^2?, Cl^?, F^?, TH, TDS, NO₃^?, and COD_Mn are the major factors responsible for the poor quality of the phreatic water, while Na⁺, SO₄^2?, F^?, and TDS are the major constituents affecting the confined groundwater quality. This study is beneficial for understanding the impacts of coal mine development on groundwater quality, and safeguarding sustainable mining in arid areas.     

小屯煤矿无机和有机水化学特征及水源判别研究

为了准确判别小屯煤矿井下突水水源,在小屯矿区开展了无机和有机水化学特征研究。结果表明,研究区内玉龙山灰岩水、长兴灰岩水与第四系水或地表水存在密切水力联系,夜郎组玉龙山段含水层与长兴灰岩含水层之间水力联系密切;大气降水与玉龙山灰岩水联系密切,采空区水与地表、地下水区别较大;大气降水直接补给长兴组灰岩含水层,经含水层涌入矿井,可以根据突水中DOM特征,判别采空区水突水水源。     

隐伏岩溶地下水动态特征及水文地质模式分析

以淮南煤田潘二煤矿2次放水试验及"5.25"陷落柱突水等资料为基础,采用地下水系统分析、构造控水理论及统计分析等方法,对区内主要含水层间的水力联系和断层的导(阻)水性进行了系统分析。结果表明:奥陶系灰岩含水层与太原组C3Ⅲ段灰岩含水层之间存在密切水力联系,2个含水层水位响应和变化幅度近乎一致,而与太原组C3Ⅰ和C3Ⅱ段灰岩含水层间水力联系弱;F1断层在太原组C3Ⅰ和C3Ⅱ段灰岩含水层中为阻水断层,而在太原组C3Ⅲ段和奥陶系灰岩含水层为导水断层,DF1断层在太原组C3Ⅰ段含水层为阻水断层,而在太原组C3Ⅱ、C3Ⅲ段和奥陶系灰岩含水层中为导水断层。     

Mine Closure of Pit Lakes as Terminal Sinks: Best Available Practice When Options are Limited?

In an arid climate, pit lake evaporation rates can exceed influx rates, causing the lake to function as a hydraulic terminal sink, with water levels in the pit remaining below surrounding groundwater levels. We present case studies from Western Australia for two mines nearing closure. At the first site, modelling indicates that waste dump covers for the potentially acid forming (PAF) material would not be successful over the long term (1,000 years or more). The second site is a case study where PAF management is limited by the current waste rock dump location and suitable cover materials. Pit lake water balance modelling using Goldsim software indicated that both pit lakes would function as hydraulic terminal sinks if not backfilled above long-term equilibrium water levels. Poor water quality will likely develop as evapoconcentration increases contaminant concentrations, providing a potential threat to local wildlife. Even so, the best current opportunity to limit the risk of contaminant migration and protect regional groundwater environments may be to limit backfill and intentionally produce a terminal sink pit lake.     

Understanding Abiotic and Biotic Conditions in Post-Mining Pit Lakes for Efficient Management: A Case Study (Poland)

This study was aimed at determining whether the origin, morphometry, and hydrology of post-mining lakes affect their hydrochemical and hydrobiological parameters (i.e. water quality). The investigated post-mining lakes were very young compared to glacial lakes and represent early stages of ecosystem succession. Despite their different ages and morphometries, they are all mesotrophic and have good water quality. They have not been supplied with phosphorus and nitrogen, which can cause excessive development of pelagic phytoplankton; as a result, they share low chlorophyll a (Chl a) content, low phytoplankton biomass, and relatively high water transparency. Low abundance and species richness of zooplankton indicate low trophic levels in all of the lakes. Chl a in Lakes Przykona and Bogda?ów were within the range typical of mesotrophic lakes, while Lake Janiszew had very low Chl a, typical of an oligotrophic water body. The low N:P ratios (4–6), especially in summer, indicates nitrogen limitation of primary production. There is a risk that such a proportion of the major biogenic elements could lead to harmful cyanobacterial blooms. The lake basins were formed using quaternary deposits (sand, clay) at their bottoms; as a result, the lakes had a slightly alkaline pH (>8), which favors the development of aquatic organisms. Optimum depth helps establish lake stratification and ensures ecological stability. This applies to post-mining lakes as well; an optimum depth should be determined to ensure the development of thermal stratification, which affects lake processes.     

Lake George as a Sink for Contaminants Derived from the Kilembe Copper Mining Area, Western Uganda

Abstract  The copper mine at Kilembe in the Ruwenzori Mountains in western Uganda ceased to operate in 1978 but a steady flow of contaminants, including Cu, Co, Ni, Zn, Cd, and sulphate, continues to enter the Nyamwamba-Rukoki River, which passes through Queen Elizabeth National Park, and finally flows into Lake George. Lake George is quite shallow, alkaline, and highly eutrophic. Measuring mass-flow of contaminants, water, and suspended solids in the Rukoki River near Kasese allowed us to estimate their input into Lake George. Grid sampling of lake sediments indicated that the contaminants settle near the two mouths of the river; low concentrations in a drill core in the centre of Lake George indicate that further dispersion within the lake is small. Sequential extraction experiments on lake sediments and lake water analyses suggest low bioavailability of the heavy metals. We conclude that Lake George is a highly resilient system that efficiently immobilises contaminants. Though there is no health risk for the population under present environmental conditions, a reduction of the contaminant load is desirable.     

沁水盆地寿阳勘探区煤层气井排采水源层判识

煤层气井水源层判识,对于单井排采动态诊断、优选作业井层和制定科学的压裂方案均具有重要意义。针对寿阳勘探区煤层气井高产水问题,开展了区域水动力场和能量场、煤系砂岩和灰岩含水性、目标煤层围岩岩性连井对比、井筒与煤层围岩含水层连通关系以及典型煤层气井水源层剖析等方面的研究。研究表明,区域水动力场和煤层渗透率是煤层气井平均产水水平的决定因素,而煤层气井产水量的井间差异主要受控于单井波及范围内局部地质工程因素(断裂、压裂缝类型和高度及岩性组合),水力压裂缝是除断裂外煤层与围岩含水层沟通的一种方式。通过综合分析,本文取得的结论是,煤系砂岩是寿阳勘探区煤层气井的主要水源层,太原组灰岩对排采的影响有限。建议在煤层气开发井层优选和压裂方案设计时,重点考虑目标煤层与砂岩含水层的垂向组合关系。     

Long-Term Time-Series Analysis to Understand Groundwater Flow in Abandoned Subsurface Mines with Application to a Coalfield in Liège,Belgium

Complex underground flow processes can occur in flooded mine workings. As the groundwater rebounds, outbreaks, flooding, and slope stability problems can occur where hydraulic pressures build up in less drained areas. A time-series statistical analysis was conducted to understand how exploited areas in an abandoned coalfield were connected and to calculate groundwater response times to rain events by spatially and temporally correlating piezometric levels and discharge rates. Ten years of flow rate and water level data were statistically analyzed for an abandoned coalfield in Liège (Belgium). Then, the results were compared to results from physically-based simulations (a 3D groundwater flow model) based on data from the first 2 years of monitoring. The statistical approach gives qualitative indications on the interconnections between the different areas of the coalfield, as well as on the storage capacity/transmissivity of the aquifer. Improved understanding of this hydrogeological behavior can be used to prevent post-mining accidents and assess the associated risks.     

南泥湖露天矿区采场水力联系及矿坑涌水量预测

为了查明南泥湖露天矿区采场范围内水力联系及矿坑涌水量,分析了含水层类型及其富水性特征,地下水补给、径流、排泄条件,地下水的基本特征等,基于此,采用长期水文监测、示踪试验及水化学分析等方法,研究了大气降水、地表水、地下水及矿坑涌水之间的水力联系及相互转换关系;并分析了露采矿坑的涌水因素以及预测了露采矿坑涌水量,主要包括矿坑大气降水补给量、地表径流量和地下水补给量。研究为后期水文地质监测以及地质灾害防治提供了技术支持。     

Evaluating the Origin of Seepage Water in the Golgohar Iron Mine,Iran

The Golgohar mine produces iron ore from an open pit in south-central Iran that is now more than 100 m below the water table, and dewatering has not solved the mine’s water seepage problem. Previous studies had reported that Kheirabad (Sirjan) Playa, 13 km north of the mine, was the most probable groundwater source. A combination of geological, hydrogeological, hydrochemical, and isotopic techniques were used to evaluate the hydraulic connectivity between the mine and the lake, and to characterize the probable water sources. Thirty-two surface and groundwater samples were collected and analyzed for major and minor (Li, B, and Br) constituents. Ten water samples were analyzed for oxygen-18 and deuterium and three samples were analyzed for tritium. The results indicated that impermeable formations and very low-permeability alluvial deposits lie between lake and the pit. In addition, the chemical and isotopic signatures of the two water sources indicated different origins. Inverse geochemical modeling and the mine water’s isotopic signatures suggest that the water is coming from the surrounding alluvial aquifer, or is deep basin water from within the fractured bedrock, or a mixture of the two.     

有机-无机联合矿井突水水源判别方法

溶解性有机质(Dissolved Organic Matter,DOM)在随地下水运移过程中,不同含水层水中DOM含量、类别、荧光强度等均存在较明显差异,因此结合无机水化学,开展了有机-无机联合的矿井突水水源判别方法研究,结果表明:地下水中无机组分浓度分布具有垂向分带性,利用pH、矿化度(TDS),HCO3,SO4等无机指标,可以判别浅部含水层和深部含水层水化学特征差异; DOM进入含水层后发生氧化还原反应强烈,其浓度(TOC含量和UV254)变化快、差异大,可以识别地表水与第四系水的水化学特征;第四系与白垩系含水层,以及覆岩破坏范围内的细分含水层,水中无机组分和有机组分含量非常接近,而荧光指纹技术灵敏度高,可以根据3DEEM光谱图分析DOM类型和荧光峰强度等差异,区分相邻含水层的水化学特征差异。陷落柱等地质异常体作为特殊的地质环境体,其内部水体中DOM相对丰富,其DOM含量和荧光指纹特征与奥灰水差异显著。将有机-无机联合开展不同含水层水化学特征分析,能够很好地区分不同水源,为矿井突水事故发生时快速判别水源提供科学依据。     

Predicting Open Pit Mine Inflow and Recovery Depth in the Durvuljin soum,Zavkhan Province,Mongolia

Increasingly, mine issues and water resources are being managed on a watershed basis, while addressing problems at the local mine scale. A good example of this developed when empirical and analytical modelling of the potential inflow to an open pit mine in the Durvuljin soum, a region in northwest Mongolia, indicated that inflow would be on the order of 0.3 to 10.5 L/s. In this study, the radius of influence due to open pit mining was estimated to be between 0.6 and 3 km. Based on simulated drawdown contours and transient pit inflow figures that captured the impact of mining and groundwater inflow rate variations over a period of time, it appeared that advanced dewatering will not be required at this mine, unless currently unknown major fractured structures are intercepted. In-pit basal sumps and pumps should be sufficient to remove water from the mine floor. However, an assessment of the final pit level is also crucial to planning the post-mining surface and groundwater quality/eco-system and mitigation requirements during recovery. Our post-mining water table recovery estimate indicated that inflow will exceed evaporation and that a shallow lake will likely form. While such solutions, which do not rely on complex numerical models nor excessive input data, are not appropriate for all hydrogeologic situations, they are relevant to the conditions encountered at most mine sites.     

Analytic calculations of hydraulic conductivities above longwall coal faces

The paper decribes a theoretical investigation into the zones of increased hydraulic conductivity caused by rock failure above a longwall panel. Primitive stresses are determined from empirical expressions and induced stresses are calculated using previously derived analytic formulae. Principal components of the resultant total stress distribution are subjected to Mohr and Griffith failure tests to determine regions of failure. The predictions are illustrated graphically by means of contour diagrams. Predicted failure heights are correlated with existing experimental values and fracture conductivities are investigated by a comparison of theoretical, field and laboratory results.     

地下水溶解碳酸盐中碳氧稳定同位素组成特征与演化规律

利用任楼井田及所在的临涣矿区生产矿井常观孔、矿井出水点,从上而下分别取第四系第四含水层、二叠系煤系砂岩含水层、石炭系太原组岩溶含水层及奥陶系岩溶含水层24个水样,测试溶解碳酸盐中δ¹³C与δ¹⁸O,分析¹³C与¹⁸O组成特征与演化规律.研究结果表明：任楼井田及所在的临涣矿区地下水溶解碳酸盐δ¹³C变化幅度大,碳循环复杂,土壤水补给机理、同位素交换反应机理和含水层围岩成分溶解机理明显;含水层碳酸盐岩含量决定溶解碳酸盐δ¹³C与δ¹⁸O的变化关系,碳酸盐岩含量越高,δ¹³C随δ¹⁸O变化斜率减小;四含水因埋藏较浅并受煤层开采影响,处于相对“开放”系统内进行地下水循环,煤系水循环系统相对比较封闭,岩溶含水层虽然埋藏深,水循环系统相比四含“封闭”,但地下水径流速度快,补给源区水力梯度大,可能为山区补给.     

Impact of Mining Activities on Groundwater Level,Hydrochemistry, and Aquifer Parameters in a Coalfield’s Overburden Aquifer

Changes in groundwater level, hydrochemistry, and aquifer parameters were studied by following disturbances caused by tunnel excavation in a panel in the Ningtiaota coalfield, northwest China. Temporal changes of hydrochemical compositions were evaluated based on time-series hydrochemical data in three boreholes (J2, J13, and SK8). The time series of hydraulic conductivity and specific storage of aquifers were obtained using the water level response to Earth tides and long-term (from 2014 to 2019) hourly recorded water level data. The results showed that the concentrations of Ca²⁺, HCO₃^?, and TDS in groundwater in borehole J2 decreased sharply following underground tunnel excavation and recovered after six months. Back and forth changes also occurred in the hydrochemical types (HCO₃–Ca?→?HCO₃–Ca–Mg?→?HCO₃–Ca). The excavation caused changes in hydraulic conductivity (about 2 order of magnitudes) and groundwater level (about 3.2 m), possibly by unclogging fractures. This in turn caused hydrochemical changes, such as silicate dissolution and calcite precipitation, possibly due to inflow of dilute water from neighboring aquifers. After the disturbance, the concentrations of Ca²⁺, HCO₃^?, and TDS in groundwater gradually recovered as the aquifer and groundwater levels both tended to recover, possibly due to the reclogging of fractures. This study on the coupled evolution of hydrological processes could enhance our understanding of the effects of mining on aquifer systems.

     

Analysis of Groundwater Inrush Conditions and Critical Inspection Parameters at the Baixiangshan Iron Mine,China

The Baixiangshan Iron Mine is a large, complex deposit. The mine is endangered by several groundwater inrush factors: multiple aquifers, high water pressure, transmissive faults, and minor hidden faults, joints, and fissures. Through a systematic hydrogeological investigation, locations where the major roadway intersected with faults in the aquifers were identified. Critical inspection parameters to predict the potential of groundwater inrush were then calculated for the intersections between the major roadways and the transmissive faults. Finally, control measures are proposed that incorporate the high groundwater pressure and the high dip angle faults. The results of this research can be applied during development of the Baixiangshan Iron Mine.     

压水试验在隧道深竖井施工中的实践应用

高黎贡山隧道深竖井含水层层数较多、较厚,破碎带较多,地质构造异常复杂,掘砌过程中存在较大的突水问题。对竖井进行地面预注浆后,采用压水试验检验地面预注浆的技术成果,压水试验整个过程是通过止浆塞封水,分段压水,利用满足压水流量的变档调速泵设备,调节压水流量实现多级次压水试验,并结合立井井筒地面预注浆效果压水试验检验方法,将压水试验应用于高黎贡山隧道深竖井地面预注浆施工中。试验结果认为：在水文地质条件异常复杂的隧道深竖井地面预注浆工程施工中,压水试验同时能够准确地计算出含水层渗透系数及井筒剩余涌水量,检测地面预注浆效果显著。研究结果表明：压水试验是检验隧道深竖井地面预注浆效果的科学有效方法,同样适用于含水层较多、较厚,地质构造异常复杂,破碎带较多的非煤矿领域,取得了良好的应用。