Numerical Simulation of Mine Water Inflow with an Embedded Discrete Fracture Model: Application to the 16112 Working Face in the Binhu Coal Mine,China

Properly accounting for the effect of heterogeneity of aquifers and accurately predicting mine water inflow during the mining process is still a challenging problem in China. We developed a stochastic modelling methodology that considers a large range of possible multi-scale fracture configurations and heterogeneous porous rock to predict mine water inflow close to the observed data. The coupled discrete fracture–rock matrix models were built for the Binhu coal mine 16,112 working face with the Monte Carlo method. The models were solved using the embedded discrete fracture model to calculate groundwater inflow from the aquifer beneath the coal seam floor. The calculated results and the observed groundwater inflows in the field agreed well. Sensitivity analysis indicates that groundwater inflow increases with increased fracture length and fracture density. The effect of natural fractures introduces a large uncertainty for the models, due to the existence of long fractures that could act as conduits between the Ordovician limestone and no. 14 aquifers. The results highlight the importance of multi-scale fractures on modeling and simulating flow in the mine area.

     

基于相关分析法的煤矿涌水量预测

矿井水害是威胁煤矿安全生产的重要因素之一.在分析煤矿水文地质参数、含水层特征及煤层特征及煤矿开采特点的基础上,选取相关分析法进行矿井涌水量预测.利用数理统计皮尔逊相关系数分析矿井涌水量与其相关因素之间的密切程度,选取SPSS软件建立了矿井涌水量与煤炭产量、掘进进尺及工作面断面面积之间的相关关系;建立矿井涌水量预测方程,...     

Relationship Analysis of the Degree of Fault Complexity and the Water Irruption Rate,Based on Fractal Theory

Fault structure significantly affects the likelihood of mine water inrush events. In this study, fractal theory was applied to the distribution of fault structures in a deep mining area of the No. 2 mine, Pingdingshan City, China. The results revealed a fractal dimension ranging from 0.602 to 1.672 for fault structures in 35 planes. Using the fractal dimension as a fundamental characteristic, the complexity of fault structures was quantified and categorized into five levels, with the overall complexity of the fault network in the study area classified as moderate. Nine mine water inrush events were used to establish a relationship between the fault fractal dimension and the water irruption rate, which was found to increase with the fractal dimension. Finally, differences in fault fractal dimension and fault complexity level are discussed and analyzed.     

Groundwater Source Discrimination and Proportion Determination of Mine Inflow Using Ion Analyses: A Case Study from the Longmen Coal Mine,Henan Province,China

Complex hydrogeological conditions in China’s coal mines have contributed to frequent mine water disasters. A simple and effective method to determine water inflow sources and paths is therefore essential. The Longmen Mine, located in Henan Province, in central China was used as a case study. A Piper diagram and cluster analysis were used to screen the characteristic values of 18 water samples from potential aquifers. A comprehensive fuzzy evaluation of the groundwater ions was carried out to determine the main source of the total mine inflow. Then, based on conservation of ionic masses, a matrix function was established to calculate the groundwater recharge composition. Finally, using measured water inflows for the Cambrian limestone aquifer, the calculated and observed results were compared. The results showed that the Carboniferous Taiyuan Formation limestone aquifer (the L₇ limestone aquifer) accounts for 60.8% of the total mine inflow, while the Cambrian limestone and roof sandstone aquifers account for 34.8 and 4.4% of the inflow, respectively. The normal mine inflow totals about 19,200 m³/day, of which 6,840 m³/day is from the Cambrian limestone aquifer. This agrees well with the calculated value of 6,720 m³/day. Thus, the method is feasible and reliable.     

基于三元混合模型的滨海金矿矿井涌水水源分析

为查明三山岛深竖井建设区域矿井涌水源,选用三元混合模型分析法对三山岛矿井涌水水样进行化验分析,利用矿化度(M)和SO2-4、Mg2+浓度的线性相关性,建立地下矿山涌水源三元混合模型并计算.结果表明:模型方法简单便于操作,能够很好地判断矿井涌水水源构成;矿井涌水在浅部主要来源于海水,其次是基岩卤水,少量第四系水,随深度增...     

Evaluation of Floor Water Inrush based on Fractal Theory and an Improved Analytic Hierarchy Process

A new evaluation model, based on fractal theory and an improved analytic hierarchy process (IAHP), was developed to predict the potential for water inrush. Fractal theory was used to quantitatively evaluate the complexity of the fault zones, which is a major water inrush factor. Study of the Lu-an mining area showed that the faults there can be subdivided into four levels of complexity: simple, medium, relatively complex, and complex. The overall complexity of the fault network in the study area was moderate. The IAHP was used to study the potential for coal floor water inrush through these faults. The results indicated that this mining district can be divided into risk-based zones. The extremely high risk zones were mainly located in the northern Tun-liu mine and the northern Chang-cun mine; high risk zones were primarily distributed in the Tun-liu mine and the southwestern Wang-zhuang mine. All other mines were classified as medium and low risk zones.     

薛湖煤矿矿井充水主控因素与矿井涌水量预测研究

河南薛湖煤矿在开采过程中受到了水害的影响,为了确保煤矿安全、高效生产,分析了矿井水文地质条件,研究了矿井冲水的主控因素,并对矿井涌水量进行预测计算。研究结果表明,薛湖煤矿矿区发育六大含水层（组）和三大隔水层（组）,煤系地层的二叠系砂岩裂隙含水层是危害矿井生产的主要含水层,随着生产的进行,顶板砂岩水多被疏干,对生产的安全不会造成很大的影响。二2主采煤层的直接充水水源为二叠系二2煤层顶板砂岩裂隙承压水,间接充水水源为二2煤层底板和奥陶系灰岩岩溶裂隙承压水,矿井的自身采空区积水是薛湖矿的充水水源之一。二2煤的导水途径主要有裂隙、断层和封闭不良钻孔3种,高角度正断层可能成为导水通道。越往深部开采水压将会越大,构造和裂隙的发育增加了底板水涌入矿井的危险。选取比拟法和稳定流解析法对采区矿井涌水量进行计算,比拟法计算的全矿井正常涌水量656 m 3/h、最大涌水量787 m 3/h比较符合近年来矿井充水的实际情况,可以作为下一步矿井开采的依据。但随着开采水平的不断延深,太灰岩溶水向矿井突水的概率也将大大提高,若出现短期内多点突水情况,将会超过比拟法预算的最大涌水量。     

基于灰色神经网络的矿井涌水量预测

针对矿井涌水系统的复杂性和随机性,提出采用神经网络修正灰色残差模型对矿井涌水量进行预测,既利用GM(1,1)模型能较好预测涌水量发展趋势的特点,又利用神经网络对于复杂非线性系统的优越性,保证了模型的精度,克服了单个模型所存在的不足。结果表明,该模型方法在矿井涌水量的预测中是可行的。     

Using Multiple Methods to Predict Mine Water Inflow in the Pingdingshan No. 10 Coal Mine,China

To ensure safe mining of the no. 2 coal seam in the Pingdingshan No. 10 coal mine, three methods (analogue, big well, and numerical simulation) were used to forecast mine water inflow and their performance. The big well method predicted the largest water inflow: 233.8 m³/h in the ?230 m level and 281.1 m³/h in the ?300 m level. The numerical simulation predicted the least inflow, 205.7 and 228.6 m³/h respectively for the 230 and ?300 m levels; this was closest to the measured values. Based on this work, it appears that combining numerical simulations with other methods are a good way to accurately forecast mine water inflow.     

龙门煤矿矿井涌水量预测及水文地质类型评价

龙门煤矿矿区位于河南省偃龙煤田西段,属佛光（偃师市）—龙门（洛阳市）水文地质亚单元的一部分。根据地层厚度、岩性、富水性及渗透性等特征,将矿区地层划分为6个含水层和5个隔水层;矿井充水条件主要分为充水水源、充水通道和影响充水强度因素;采用“大井法”和“比拟法”对矿井涌水量进行预测,得出:未来生产矿井的最大涌水量按正常涌水量的1.13倍计算。根据矿井水文地质类型划分依据判断,洛阳龙门煤业有限公司龙门煤矿水文地质类型划分为极复杂类型。     

长汀矿区矿坑涌水量模糊水文地质比拟法预测

基于长汀矿区勘探资料,分别从含水层组特征、断裂构造带水文地质特征、地下水补给、径流、排泄特征、矿井充水类型等方面对该矿区的水文地质条件进行了分析,结果表明:1矿区侵蚀基准面以上的主要充水来源为大气降水、接触裂隙水和断层接触水;2矿区侵蚀基准面以下的主要充水来源为接触裂隙水和断层接触水;3矿区地下水补给主要来源于大气降水,浅部可直接获得补给,深部通过裂隙和断层间接获得降水补给。在上述分析的基础上,基于矿区用水量实测资料,采用模糊水文地质比拟法、传统水文地质比拟法预测的矿坑涌水量分别约为44.69,46.73m3/h。尽管模糊水文地质法的预测结果略小于传统水文地质比拟法,但由前者充分考虑了降雨量、水头降深、开采面积、给水度、渗透系数和补给水源等因素,故其预测结果相对于传统水文地质比拟法而言可靠性更强。分析结果对于精确预测该矿区矿坑涌水量,确保井下安全开采有一定的参考价值。     

深部开采构造型突水危险性数值模拟分析

本文以三山岛金矿为工程背景,利用FLAC3D数值软件建立矿井深部开采流-固耦合数值模型,采用房柱式交替向上充填采矿法,在模拟采动条件下,尤其是采场通过F3断层时,矿体、充填体内渗流场以及塑性区的演化过程,对矿井不同开采时段、不同开采区域的突水危险性进行分析.试验结果表明:①距离断层较远时(-825 m-1盘区),随着回...     

基于水力学与水化学耦合的矿井涌(突)水水源识别方法研究

解决当前水源识别仅考虑矿井水化学特性及水位观测等少量因素,缺乏矿井突水力学支撑相关问题,以林西煤矿1021中回采工作面为例,提出了一种基于水力学与水化学耦合的矿井涌(突)水水源识别方法。该方法首先根据封闭不良钻孔、断层、老空区、底板等矿井突水力学模型,求解涌(突)水点不同水源或通道突水的临界防隔水煤岩柱厚度Lv|其次对比Lv和实际隔水煤岩柱厚度Le之间定量关系,判定不同水源突水的先验概率|然后以先验概率为纽带,利用贝叶斯判别分析,建立基于水力学与水化学耦合的矿井突水水源识别模型|最后利用该模型对1021中回采工作面涌水点水源进行验证识别。研究结果表明：由于第Ⅲ含水层、第Ⅳ含水层水化学特征相似,建立单一的水化学识别模型,会将涌(突)水点水源误判为第Ⅲ含水层水。而基于水力学与水化学耦合的水源识别模型可精确识别出该涌(突)水点水源属于第Ⅳ含水层水,判识结果与工程实际情况一致,有效提高了矿井涌(突)水水源识别精度。     

Prediction of Water Inrush from Coal Seam Floors Based on the Effective Barrier Thickness

Floor water hazards pose an increasingly prominent risk in China as coal mining depths progressively increase. Two general models of complete and structural floor water inrush that consider the coupled effect of mining stress and water pressure were developed to address the problems caused by highly confined aquifers under these complex stress conditions. We developed an integrated floor water inrush model, and the floor rock mass was rezoned based on the deformation, failure characteristics, and water inrush mechanism of water-resistant floor strata under the combined action of confined water pressure and mine pressure. The formation of the coupled solid–fluid confined water uplift zone was studied from the perspective of fracture propagation. A formulation was obtained that describes the confined floor water under the coupled effects of mine pressure, water pressure, and solid–fluid interaction. An inrush risk prediction is proposed that considers the relationship between the confined water pressure and horizontal principal stress in the bottom plate’s pressure relief zone.

     

Dynamic Characteristics of Water Inflow from a Coal Mine’s Roof Aquifer

The static and dynamic inflow of water from the roof aquifer changes as mining progresses. We used a second-order dynamic model to describe the water inflow process. The parameters of the water inflow model were solved using actual drainage from roof aquifers at nine working faces in the Yuanyanghu mining area of the Ningxia Autonomous Region, China, as well as the peak water inflow values, their locations, the equilibrium values of water inflow, and their initial occurrence locations. The parameters of the second-order dynamic model of water inflow were inversely calculated. The peak values of water inflow without drainage were also calculated. The results indicate that pre-drainage of roof water significantly weakens the intensity of water inflow during the mining process, reducing peak values by more than 72%. The characteristics of the water-conducting fractured zones determine the major drainage locations, while the water-rich and water-conductive nature of the direct discharge aquifer affects the water inflow equilibrium values and initial occurrence positions. The results show that the model parameters and characteristic values of water inflow are determined by the hydrogeological nature of the roof strata, water-conducting fractured zone(s), and mining speed.

     

复杂断层带富水性矿井瞬变电磁法探测研究

复杂断层带富水性的探测关系到矿井的采掘安全。探讨了矿井瞬变电磁法超前探测的基本原理与技术方法,分析了断层带富水性的地球物理响应特征,结合某矿巷道掘进前方断层带出水位置的矿井瞬变电磁法探测,提出了立体探测方案,对探测结果进行了分析解释,得到钻探验证。研究表明,利用矿井瞬变电磁探测技术可以有效地获得掘进巷道前方复杂断层带的富水程度、位置和范围,可以为掘进巷道防治水工作提供可靠的技术保障。     

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).     

数值模拟在煤矿涌水量计算中的应用

通过对东欢坨矿区北部补给区的分析,研究了该矿的涌水特征。根据不同水平涌水量特征,分析了地面降水、开采长度、开采深度和涌水量的关系,建立了数学模型。利用有限元差分计算,预测了该矿不同水平的涌水量,结果令人满意且真实可信,为今后的井下防治水工作提供了可靠的理论依据。     

Calculation of mine water inflow using interactively a groundwater model and an inflow model

The uncertainty of the pre-evaluation of potential ground water inflow rates in underground mines results in difficulty in planning and costing the water related activities of the mines. This paper presents a procedure for making a rational assessment of the potential inflows. The method is based on an interactive operation of two computer models: an inflow model and a ground water finite element model. Both are first calibrated using existing information obtained from aqui fer monitoring. In a second phase, the models prelict the potential inflows as well as the impact of mine dewatering on the piezometric surface. Both the models used are based on a non linear relationship between tonnage mined and inflows. A phased behaviour in the rates of inflow increase is noted. The interactive mode of operation of the models results in confidence in the prediction because the models output (calculated inflow rates and piezometric levels) during the calibration phase are checked against the historical data. It is concluded that the method can provide mine management with guidelines for dewatering requirements under the condition that reliable data on the history of piezometric levels be available.     

司家营铁矿北区矿坑涌水量预测

司家营铁矿北区位于滦河二级阶地和河漫滩上,矿区水文地质条件较为复杂,包含4个含水岩组。利用大井法和数值法对矿区各开采中段的涌水量进行了预测,结果证明两种方法计算结果较为接近,并且与矿山生产采场的实际涌水量相符,但数值模拟法相对误差更小,其计算结果可推荐为采场防排水设计依据。