神府矿区采煤对地下水循环的影响——以窟野河中下游流域为例

以窟野河中下游地区为例,通过野外调查和水化学特征分析,总结了神府矿区地下水循环模式：第四系潜水和侏罗系烧变岩潜水主要受地形控制;延安组碎屑岩含水层分5个含水层段,主要受地层倾向控制,沿河道相由东向西流动。进而提出了采煤对地下水影响机制：浅部煤层开采破坏了潜水含水层之下黏土层的隔水性,含水盆地汇水面积减小,泉流量减小或干枯;同时采矿造成的人为“溯源侵蚀”袭夺了相邻水文地质单元的地下水,矿井水补给量增加,蒸发量减小;深部煤层开采进一步破坏黏土隔水层,导致潜水含水层消失,使得地表径流转换为地下径流,地下水完全依赖5-2号煤层底板径流。     

路堑边坡渗流场的有限差分分析与工程实例

渗流问题是边坡稳定性分析的重点、难点之一。该文以有限差分法求解渗流问题的原理为基础,基于山西省阳泉市307国道复线路堑边坡的边界条件和地质模型,运用有限差分软件深入分析了侧向和垂向双向补给条件下坡体中渗流场的特征,所得浸润曲线几何特征与实际情况十分吻合,为边坡稳定性评价提供了详实的水文地质资料。     

宁夏王洼煤矿矿井涌水分析与涌水量计算

 在分析宁夏王洼煤矿地质及水文地质条件的基础上,对矿井的充水因素进行了论述,认为区内的第四系遍布全区,普遍含孔隙潜水,但由于其钻孔揭露最大厚度较小,导水裂隙带的最大破坏高度尚未达到该含水层,所以该含水层对煤矿开采影响较小;影响区内煤矿涌水量的主要含水层为中奥陶系、上三迭统延长群、下侏罗统延长群、中侏罗统直罗群、上侏罗统安定群、第三系、下白恶统六盘山群。采用富水系数比拟法、狭长水平巷道水动力学法、矿井实测排水量对煤矿涌水量进行了计算,通过对各种计算方法适应性的评述及计算结果的对比分析,认为采用大井法预测矿井涌水量比较合理。     

Ground Water Control Techniques for Safe Exploitation of the Neyveli Lignite Deposit, Cuddalore District, Tamil Nadu, India

Dewatering in deep opencast mines generally focuses on extraction of seepage water from the phreatic zones above the ore/mineral deposits and storm water that collects in mine pits. But at the Neyveli lignite deposit in the Cuddalore District, there was a danger of the mine floor bursting due to the hydrostatic head pressures in the underlying thick confined aquifers, a problem not previously encountered anywhere in India. Hydrogeological studies established the feasibility of mining the lignite by maintaining a constant cone of depression (pressure relief) in the surrounding aquifers below the mine by continuous pumping through a pre-planned network of wells. This depressurizing process had to be designed to tackle multi-layered confined aquifers and water table conditions. This paper traces the multi-faceted evolution in developments to control ground water at the Neyveli Mines.     

Using Time Series Analysis of Coal Mine Hydrographs to Estimate Mine Storage,Retention Time,and Mine-pool Interconnection

Understanding flow-system dynamics of underground coal mine complexes is essential to designing in-situ remediation. Such complexes can be studied by applying time series analysis to the precipitation series and well and mine discharge hydrographs. The Corning mine complex discharges acid mine drainage into Sunday Creek in Ohio, USA. Analysis of the Corning discharge shows that the aquifer has a short (9 days) response time and has little capacity for long-term storage. A time lag of 3–4 days occurs between precipitation and discharge, which corresponds to pressure pulse propagation displacing stored mine water, rather than actual advective flow of water. A gradual decline in hydraulic head is observed from the unsaturated recharge area to the fully flooded discharge area. All well hydrographs show a similar seasonal trend, with mine water levels peaking in early summer, and reaching their lowest levels in early fall, consistent with seasonal recharge patterns. A relatively isolated and fully saturated portion of the mine is sensitive to diurnal barometric pressure, as is typical of confined aquifers, with well water level declining as pressure increases. Other portions of the mine behave as unconfined aquifers, insensitive to barometric pressures. The results also demonstrate the important spatial heterogeneity of the aquifer and indicate that the mine does not behave as a single pool.     

Origin of mine water by using environmental isotope technique in water-logged Coal Mines,Pingdingshan, China

Pingdingshan Coal Mining Area lies in the western part of Henan Province, and the No. 7 mine is located at the area of south-west corner. With the increase of the mining depth, the threat of karstwater from aquifer underlying the coal seam become progressively alarming to the mine workings. A research program was undertaken to investigate into the hydrogeological conditions of the coal mine, employing environmental isotopes techniques. Through the complete and systematic analysis upon the atmospheric precipitation, hydrochemistry of the surface-water and groundwater, oxyhydrogen isotopes, the following factors have been ascertained: a) the creating, distributing and migration laws of the groundwater in No. 7 mine: b) the recharge sources and the combination mechanism of the mine-water; and c) the proportion of the surface water in mine water and its age by separating the component of the minewater. The research revealed that the major recharge source of the groundwater at No. 7 mine is surface-water, and more specifically speaking is the impulsively concentrated, water-release rechard from the draining channels of reservoirs, and the perennial river leakage recharge of which the leakage zone are Cambra limestone exposed in the channels and the river valleys. The surface water recharged during one year accounted for more than 90 percent of the total mine-water discharge, while the ages of water in different aquifers ranged from 1–1.2 year. This research provides scientific basis for making plan of the mine-water control.     

Groundwater Recharge Assessment in an Arid,Coastal, Middle Mountain Copper Mining District,Coquimbo Region,North-central Chile

Groundwater recharge processes operating in a portion of the western slope of the Chilean Coastal Cordillera (30°S) were assessed. The study takes advantage of the presence of the Cerro Brillador Mine (CBM), currently part of the Universidad de La Serena mining research center. Six factors—slope, solar exposure, drainage density, lineament density, geology and vegetation were characterized in a 12 km × 12 km area around the mine to identify the zones of greatest and least potential for groundwater recharge. The analysis indicates that approximately 66% of the total area presents favorable conditions for recharge. At a more local scale, the work focused on the CBM itself, an experimental facility where structural measurements in the interior and exterior of the mine, monitoring of the water level in the shaft, and sampling of mine water for chemical and isotopic composition were carried out. The chemical analysis highlighted the lack of acid drainage, despite the existence of pyrite (FeS₂) and copper-sulfate mineralization in the mine. The isotopic analysis showed that the groundwater has a similar signature to local precipitation. From this information, a simple conceptual model for the hydrogeology is proposed, in which precipitation rapidly recharges the mine along faults and joints with a preferential N-S strike, but is impounded by the Urrutia fault, which facilitates the storage of groundwater in the underground workings by acting as a flow barrier. A simple analysis suggests a recharge rate on the order of 5% of the average annual precipitation for the CBM area.

     

Evaluating Seepage Through a Homogenous Embankment: Part of Monitoring a Tailings Storage Facility

One of the Let?eng Diamond Mine’s two tailings storage facilities has high volumes of toe seepage, which could be caused by internal erosion within the embankment, a major reason for many dam failures. A resistivity survey delineated two prominent anomalies associated with saturated spots within this embankment, which might have been due to free water in the tailings supernatant pond, water from the spigotting operation moving through the dam fill as wetting fronts, or embankment ponding due to rainfall. However, standpipe piezometers indicated that these anomalies were not associated with a phreatic surface in the embankment. Constructed entirely from coarse tailings with a saturated hydraulic conductivity of 2?×?10^–05 m/s, the embankment is pervious, which inhibits development of a phreatic surface. Apart from toe seepage, there was no evidence of leaks at the embankment’s downstream face. Steady state seepage was conservatively calculated as 15 L/s, which is periodically exceeded by almost threefold. A review of toe seepage vs. rainfall and groundwater levels suggests that these seepage fluctuations were due to increased precipitation-induced groundwater recharge and runoff.

     

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。     

张双楼煤矿矿井水资源化及其综合利用

分析了张双楼煤矿矿区地下水的水资源状态及其补、径、排关系.根据矿区矿井水水质、水量及其矿井水处理、利用过程中存在的问题,按照矿井水“优水优用,减少排放,减少成本”的指导方针对矿井水处理、利用系统进行优化设计.提出了降低矿井水高矿化度经济可行的方案;确定了更能满足矿区要求的混凝剂种类;分析了建立矿井水利用节约型系统的必要性.     

Hydrologic Characteristics of a 35-Year-Old Underground Mine Pool

The hydrology of a 14,672 acre (5,940 ha) coal mine complex in Cambria County, Pennsylvania, USA, was characterized. This flooded mine complex was evaluated to determine the potential of using the mine water for downstream agricultural purposes in an adjoining watershed. The hydrologic characteristics of the mine complex dictate the amounts and rates of mine water discharge that are available. The original coal extraction rate was known to be 63%, but post-mining subsidence has reduced the effective porosity to a mean of 11%. Thus, the mine stores considerably less mine water than was anticipated, a priori. The mine receives vertical recharge averaging 0.27 gallons (gal) per minute per acre (24.6 L/s per ha), which is equivalent to 11.6% of the mean precipitation. The recharge rate fluctuates about the mean by ±22%. The low storage capacity combined with the moderately low recharge rates allow the large mine complex to be rapidly drawn down when the pumping rate is raised from 4.68 to 9.36 × 10⁶ gal (17.7–35.4 × 10⁶ L/day). Conversely, the mine refills rapidly, up to 0.8 ft (0.24 m) or spatially 33 acres (13.4 ha) per day, once the pumping rate is reduced back to 4.68 × 10⁶ gal/day (17.7 × 10⁶ L/day), which is well below the total recharge rate. In addition to vertical recharge, 6.3–40.4% of the inflow into the mine pool complex occurs from coal barrier seepage from an adjacent flooded mine. The seepage rates are relatively constant and are estimated to be insensitive to changes in head up to 50 ft (15.2 m).     

Geological Analysis and Numerical Modeling of Mine Discharges for the Sanshandao Gold Mine in Shandong,China: 1. Geological Analysis

The Sanshandao Gold Mine is one of the largest gold mines in China, and is almost completely surrounded by seawater. Factors such as water-controlling structures and water-bearing zones that developed in the mine were studied, based on geophysical exploration data and hydrogeological investigations of the wells and drifts of the mine. The sources of recharge (seawater, brine from surface runoff, and Quaternary water) were proportionally determined based on ¹⁸O isotopic and water quality data measured for each drainage point in the pits. Appropriate boundary conditions were defined for the recharge source of the seawater and natural runoff brine. The hydraulic connections among the water-bearing zones were also considered. This work was conducted to prepare for future mine development and allowed us to simulate anticipated ground water flow.     

Geochemical Characterisation of Seepage and Drainage Water Quality from Two Sulphide Mine Tailings Impoundments: Acid Mine Drainage versus Neutral Mine Drainage

Seepage water and drainage water geochemistry (pH, EC, O₂, redox, alkalinity, dissolved cations and trace metals, major anions, total element concentrations) were studied at two active sulphide mine tailings impoundments in Finland (the Hitura Ni mine and Luikonlahti Cu mine/talc processing plant). The data were used to assess the factors influencing tailings seepage quality and to identify constraints for water treatment. Changes in seepage water quality after equilibration with atmospheric conditions were evaluated based on geochemical modelling. At Luikonlahti, annual and seasonal changes were also studied. Seepage quality was largely influenced by the tailings mineralogy, and the serpentine-rich, low sulphide Hitura tailings produced neutral mine drainage with high Ni. In contrast, drainage from the high sulphide, multi-metal tailings of Luikonlahti represented typical acid mine drainage with elevated contents of Zn, Ni, Cu, and Co. Other factors affecting the seepage quality included weathering of the tailings along the seepage flow path, process water input, local hydrological settings, and structural changes in the tailings impoundment. Geochemical modelling showed that pH increased and some heavy metals were adsorbed to Fe precipitates after net alkaline waters equilibrated with the atmosphere. In the net acidic waters, pH decreased and no adsorption occurred. A combination of aerobic and anaerobic treatments is proposed for Hitura seepages to decrease the sulphate and metal loading. For Luikonlahti, prolonged monitoring of the seepage quality is suggested instead of treatment, since the water quality is still adjusting to recent modifications to the tailings impoundment.     

露天边坡地下水渗流模拟及降水坡降研究

以伊敏露天矿三采区设计采矿为工程研究背景,采用物理模拟与数值模拟相结合的方法,分析地下水渗流规律、边坡采动渗流变形规律、及降水对边坡渗流规律影响。基于相似模拟研究了露天开采过程中地下水位渗流动态过程、坡面出水位置、渗流水力坡降特征及地下水通过断层后出现水位跃变;通过数值模拟研究了7种不同降水工况中边坡中浸润线的变化特征、地下水在断层处跃变规律、及地下水的水力坡降特征。最终,确定了矿区合理的降水位及水力坡降。     

降雨补给潜水的滞后分配

大气降水入渗补给潜水存在着滞后效应。入修补给潜水的过程是一个正偏态曲线，可用瑞利分布来描述，把大气降水入渗补给量合理地分配到各计算时段中去。本文通过实例讨论了降雨补给潜水的滞后分配问题；以端利分布为核函数来描述降水入渗补给潜水的过程时，所需的分布参数（尺度参数β和随机变量x）可用滞后时间长度Ts与入渗时间长度Ti来求得，而Ti、Ts可按野外长现资料确定出。     

Numerical Simulation of Inrush Water Spreading Through a Mine: A Case Study of the Beixinyao Mine,Shanxi Province,China

Studies on risk assessment and prediction of inrush water in mines are available, but the evolution process of water inrush events is unclear, which makes it difficult to formulate control and rescue measures. In this paper, a novel numerical simulation approach has been developed to calculate and analyze the spreading process for water inrush in a coal mine in Shanxi Province, China. Possible inrush scenarios for the mine were created based on the water-filling conditions, inrush risk analysis, and the mining works. A spatial model for the mine was constructed, providing the preconditions for numerical modeling. Furthermore, a coupling model for the water flows in the roadway and the goaf was created based on pipe-flow and non-Darcian seepage theories. A numerical solution was then used to resolve the spreading processes for the inrush. The proposed approach was verified through a model experiment for the roadways and a CFD simulation of the goaf. The simulation results for the water inrush scenarios reveal the mine areas susceptible to inundation; these areas can be delineated at different times. The inundation area is related to the mine structure and is mainly controlled by the position of the localized high and low elevation points. The time for inundation is affected by the cumulative water inrush. This study provides a method for assessing the inundation risk of a mine in the event of water inrush disasters.

     

铁南矿充水因素的分析

矿井直接充水水源为煤系地层裂隙孔隙水,开采初期揭露含水层后,矿井涌水量增加较大,主要以疏干漏斗范围内的贮存量为主,漏斗稳定后,矿井涌水量以地下水的侧向补给为主。粗粒含水层的富水性和导水性相对较好,以孔隙为主的渗入性通道是矿井充水的主要途径。     

Effect of subsidence on recharge at abandoned coal mines generating acidic drainage: The Majestic Mine, Athens County, Ohio

This paper addresses the relationship between the geology, hydrology, and transient variations in discharge and water chemistry of acidic water discharged by an abandoned underground coal mine: the Majestic Mine in Athens County, Ohio, a partially-flooded, downdip, drift mine. The Middle Kittanning (No. 6) Coal (Allegheny Series, Pennsylvanian System) was mined room-and-pillar until 1921. Loss of support from mine collapse has created large vertical subsidence fractures along the naturally occurring joints within the brittle sandstone overburden. The mine discharge hydrograph, temperature, and pH of the mine discharge indicate that the hydrology of the Majestic Mine can be explained in terms of pseudokarst hydrology. During rainfall events, water is preferentially recharged through the subsidence features. Increased pressure from the mine inflow is transmitted through the flooded workings, causing a rapid increase in discharge, and forcing older mine water out of the mine. A stream draining an overlying watershed is captured by one of the subsidence features, contributing 60 to 80% of the mine water outflow. During the summer, recharge to the mine is negligible because potential evapotranspiration is higher than precipitation. During late summer and fall months, when the mine pool is at its lowest elevation, atmospheric oxygen penetrates back into the mine workings, enhancing the oxidation reactions. During the increased discharge of the spring months, washing of the reaction products from the mine walls produces the highest metals concentrations and chemical loads. *** DIRECT SUPPORT *** A03BX002 00004     

恒源矿构造特征及其对矿井水的控制机理

针对地质构造的存在使得矿区水文地质条件复杂化的问题,在构造发育规律和演化的基础上,系统论证了构造对矿区含水层形成、地下水的补给、径流、排泄及流场、水化学成分、矿井涌水和突水的控制作用。合理解释了矿区的水动力环境、岩溶发育特征、突水特征,指出了大断层控制下的小构造裂隙是矿区防治水工作的重点区域。     

Geological Analysis and Numerical Modeling of Mine Discharges for the Sanshandao Gold Mine: 2. Simulation and Prediction of Mine Discharges

A two-dimensional model is presented as a way to hydrogeologically characterize the controlling factors in the Sanshandao Gold Mine. The finite element method was first applied to simulate the ground water system of the current operation, using leakage data and the calculated recharge. An inverse model was applied to the observed data (e.g., head and discharge) to verify and calibrate the ground water simulation model and to estimate the hydrogeological parameters for the water-bearing zones. Nonlinear mathematic programming was used to solve the inverse model and to estimate the model parameters in 17 districts with different hydrogeological characteristics. The finite element equations were solved by means of a large non-symmetrical sparse equation. The results were in agreement with what is currently observed in the mine. The models and the estimated parameters were then applied to predict the mine water discharge for drifts extending to depths of −330 to −600 m during the next development stage. In order to improve the predicted accuracy of the numerical model, an iterative element mesh was added in the districts near the drainage drifts so that the computed discharges that flowed into the drifts would approach the recharges that flow into the borders of the mine. The model was also used to understand how the mine discharge would be influenced by factors such as unsteady ground water flow and the construction of hydraulic barriers to restrict ground water from entering the pits. Part 1 of this article can be found at doi:.