Geophysical Diagnosis of Diversion Channel Infiltration in a Uranium Waste Rock Pile

The Osamu Utsumi mine was the first to economically mine uranium ore in Brazil. During its operation, a river valley was buried for the construction of the waste rock pile. The original stream was diverted to the northwest side of the pile and has since flowed into a diversion channel devoid of basal waterproofing, while an acid mine drainage (AMD) source flows at the base of this waste rock pile. This research aims to evaluate the possible relationship between water infiltration of the diversion channel and the AMD resurgence at the base of the pile using electrical resistivity tomography and induced polarization. 2D inversion models and pseudo-3D maps allowed the recognition of low resistivity zones (<?100 Ω·m) with high chargeability areas (10 mV/V). Some of these low-resistivity areas have been interpreted as infiltration zones in segments of the diversion channel into the pile, and in one of them, the flow intercepts a high chargeability area interpreted as a sulfide-rich zone that is expected to contribute to AMD at the base of the pile. Understanding the hydrogeochemical process will help select effective actions to mitigate the generation of AMD at the mine, which is currently in the decommissioning phase.

     

Successful Use of Geoelectrical Surveys in Area 3 of the Gol-e-Gohar Iron Ore Mine,Iran

Geoelectrical surveys were conducted in Area 3 of the Gol-e-Gohar iron ore mine to provide geological and hydrogeological information. Open pit mining is currently underway in the northern part of the Area, and underground mining operations are planned for the southern section. Groundwater has already been encountered in the open pit mine. Twenty five resistivity soundings were first performed in the mine area; then, induced polarization (IP) measurements were carried out to remove ambiguities between clay and water-bearing layers. To investigate fault zones as water conduits, combined resistivity profiling surveys were also carried out. These measurements provided a detailed structural map of the pit area. Resistivity and IP results have subsequently been confirmed by observations at three monitoring wells and the mine pit wall. Monitoring and piezometric wells will be drilled at locations suggested by the results of the geoelectrical surveys. Drainage galleries may be developed to dewater the open pit mine. However, another option being considered is to start the underground mining with the idea that it will initially simply serve as a dewatering mechanism.     

探讨煤矿开采对地下水的影响

为了摸清闭坑矿区水文地质条件,构建了闭坑矿区水文地质概念模型。以贵州省麻江县闭坑煤矿为研究对象,通过开展高密度电阻率法、充电法、瞬变电磁法和核磁共振法等系统的物探工作,并在重点区域进行钻探,结合闭坑矿区生产资料及地质调查成果,依托EVS地质建模软件完成该闭坑矿区水文地质模型构建,实现了地下水补—径—排过程的可视化,可为闭坑矿区水污染治理提供重要支撑。

     

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.     

Electrical Resistivity Characterization of a Reclaimed Gold Mine to Delineate Acid Rock Drainage Pathways

An electrical resistivity survey was completed at the Landusky mine. The survey consisted of 15 lines on the surface of the reclaimed Suprise pit, Queen Rose pit, and the region immediately south of Swift Gulch. Additionally, wells and seeps were used by energizing electrodes in direct contact with ground water to increase the sensitivity of the resistivity method at depth. The survey was conducted to locate potential acid rock drainage pathways that are contaminating Swift Gulch. The results showed that the lowest resistivity values were coincident with the Queen Rose pit. Furthermore, the low resistivity feature appeared to trend northeast along a known fault, consistent with the geologic understanding of the site. A scatter plot of resistivity values versus total dissolved solids (TDS) showed a strong correlation (R ² = 0.85). A linear regression model suggests TDS at the lowest resistivity region to be approximately 2.5 times greater than that measured in ground water wells.     

某金矿开采项目矿坑疏排水量预测及环境影响分析

矿坑疏排水量是矿山环境保护及安全生产的重要指标,为了合理预测矿坑疏排水量并探讨其对周边环境的影响,本文以湖北某金矿为例,在充分掌握矿区地质及水文地质特征的基础上,采用符合实际条件的解析法模型结合大气降水汇入量对矿坑疏排水量进行了预测,并分析了矿坑疏排水对周边村庄饮用水、温泉、地表水及生态用水的影响,以期为类似水文地质条件的矿区进行环境保护及安全生产提供依据。     

矿井超前精细探测技术方法与应用

为了预测煤矿掘进工作面的水害,采用矿井瞬变电磁法、矿井直流电法、矿井瑞利波法、矿井反射波法4种井下超前探测技术。通过井下数据采集、处理和反演计算,形成可视化图件,来解释矿井含水体及构造的范围和位置特征,建立了一套适合煤矿掘进过程中井下物探动态监测水害的技术方法。结果表明:矿井瞬变电磁法可探测掘进工作面正前方、前方顶板、前方底板和前方侧帮含水体;矿井直流电法可探测掘进工作面正前方含水体;矿井瑞利波法(或矿井反射波法)可以探测前方构造及采空区边界。     

Estimation of the required amount of hydrological exploration in lignite mining areas on the basis of hypothetical hydrogeological models

Mine drainage is a necessary but very costly precaution for open-pit lignite mining in sandy aquifers. Consequently, the minimization of the number of drainage wells and their optimal operation become important tasks in designing mine drainage systems. Comprehensive groundwater flow models have to be used, both, for the design of drainage wells, and for the analysis of water management strategies in mining areas. The accuracy of computations with such models depends on the precision of the underlying hydrogeological informations. In order to get these informations detailed and costly hydrogeological explorations have to be done in the mining regions. The basic informations are obtained using exploration drilling. The cost for hydrogeological exploration are approximately a linear function of the number of exploration bore holes. Therefore the reduction of drilling gets a key role in reducing costs of exploration. This might be done by:

- increased use of geophysical exploration methods,

- complex analysis of exploration results using mathematical statistical methods,

- precise estimation of the required amount of hydrogeological informations.

The paper describes a mathematical approach to support the complex decision making procedure of estimating the optimal amount of hydrogeological exploration with respect to a given mine drainage goal.     

南洺河铁矿和万年煤矿水文地质特征及防治水对策

南洺河铁矿与万年煤矿同属一个水文地质单元,煤矿赋存于上部石炭、二迭系,铁矿为奥陶系与火成岩接触交代成矿,位于煤矿底部。矿山水文地质条件复杂,矿坑涌水量大,下层煤承受压力大,对矿山的安全开采构成直接威胁。通过对矿山所处水文地质系统特征的分析,用数值法预测了矿坑涌水量,并根据2矿的水文地质条件及关系,结合矿山开发利用方案,提出了2矿共用疏干排水系统,统一解决矿山水患的方案,避免重复建设,可节约大量基建和运行费用。     

Quantitative Prediction of Water Volumes Within a Coal Mine Underlying Limestone Strata Using Geophysical Methods

Mine water and mine inflow water are closely linked to the risk of mine water disasters. The relationships between various geophysical parameters and the volume of water in mine tunnels were considered by using an integrated suite of appropriate geophysical methods [i.e. direct current (DC) resistivity, transient electromagnetic method (TEM), and the seismic scattered wave method], and knowledge of the essential features of seam floor water in karst coal mine settings. By constructing a 3-dimensional physical simulation of water-bearing limestone, a quantitative predictive formula for water volume in abnormal bodies was derived in terms of the parameters of the selected suite of geophysical methods. Water volume was determined by using apparent resistivity (obtained from the DC resistivity survey and TEM), a measure of the amount of potentially water-containing space, and a correction coefficient. The quantitative formula was adjusted for accuracy using field data, and then tested at a specific field site. The average accuracy of predictions using the composite quantitative formula was 75.8 %, which is considered to be high. The formula presented in this paper could contribute significantly to the prevention and mitigation of water-related disasters in karst coal mines.     

综合物探技术在带压开采工作面中的应用

阳泉煤业集团五矿8421工作面存在局部带压区,必须查清带压区隐伏灾害地质构造及其含水情况,为工作面安全回采提供保障。通过分析不同物探方法的特点和适用条件,采用无线电波透视法、矿井瞬变电磁法、并行直流电法3种物探方法,对该局部带压工作面进行了综合探测。多种地球物理探测方法相互印证和补充,并结合地质、水文地质条件分析,最终划分出3个底板相对富水区。经采掘验证,物探结果与实际情况相符。     

西曲煤矿水文地质类型划分探讨

矿井水文地质类型划分,对煤矿的安全生产划分有着重要的意义。探讨西曲煤矿矿井水文地质类型的划分,对井田内水文地质条件及矿井充水因素进行分析,得出该矿开采受水害影响程度以及防治水工作开展的难易程度均为中等。具体为,2+3#煤层矿井水文地质类型为中等,4#煤层矿井水文地质类型为复杂,8#、9#煤层矿井水文地质类型为复杂。分析认为,该矿应加强对陷落柱的物探和钻探、本矿采空积水探放水、矿界防隔水煤柱的留设等工作,研究结果可为煤矿防治水工作提供依据,在一定程度上可确保矿井安全生产。     

电阻率测深法在煤矿水害探测中的应用

为解决煤矿断层导水和奥灰水的水害问题,以五沟煤矿作为研究对象,通过比较瞬变电磁法、可控源音频大地电磁法、高密度电法和直流电阻率测深法4种物探方法的优缺点,最终选用抗干扰能力强的直流电阻率测深法在该区进行了探测工作。研究结果表明,在地形相对平坦、接地条件好、但存在一定地电干扰的矿区采用直流电阻率测深法能够较好地探测断层的富、导水性和奥陶系灰岩顶界面地层的富、含水性。断层富、导水表现为沿断层带有低电阻率异常条带反映;奥陶系灰岩顶界面地层富、含水表现为低电阻率异常区、带反映。依据各剖面图和平面图上视电阻率变化综合反映这两种水害的表现形式,为煤矿水害探测提供了新思路和技术。     

并行电法探测技术在卧龙湖煤矿的应用

介绍应用并行电法采集系统,在卧龙湖矿井103工作面进行底板探测。通过网络并行电法数据体的三维电阻率反演,得到矿井工作面底板下三维空间的电阻率分布特征。在该工作面布置钻孔,在底板灰岩层位中电阻率为70Ω.m以下区域,出水量最大达到60 m3/h。该技术取得了煤矿工作面底板完整三维电场参数与电阻率数据体,客观反映了该工作面内底板的水害空间位置,为该矿井防治水工程提供了准确信息。     

矿井富水性超前探测及水源快速识别研究

通过对井东煤业矿井掘进巷道超前探测技术和水源识别技术进行研究,总结出矿井特有的岩体地球物理特性及水文地质特征,基于交流电放电法,研发设计了矿井富水性超前探测系统,结合矿区的水文地质特征和水样测试结果,建立了矿井水源库,并研发了矿井水源快速识别技术,成功运用于巷道富水性超前探测和水源识别。研究为类似矿井的水害防治提供了参考依据。     

复杂条件下矿井水文地质类型划分方法

矿井水文地质类型科学划分是煤矿制订防治水规划、实现防治水安全的技术前提,《煤矿防治水规定》(2009年)要求煤矿每3年评价1次矿井水文地质类型。具有多年开采历史的地质与开采条件复杂矿井的水文地质类型划分暴露出罗列矿井已有勘查资料、难以顾及不同水平与盘区水文地质条件差异、需进一步明析评价目的性和指导性等问题。以1984年曾发生特大型岩溶陷落柱突水、其后保持安全生产30 a的大型现代化矿井--开滦集团范各庄矿为例,实现了矿井水文地质类型的分水平、分盘区、分阶段评价与复杂等级划分。提出：矿井水文地质类型划分应该是对矿井当前揭露条件下水文地质特征的根本概括与评价;复杂条件下矿井水文地质类型评价与复杂等级划分应以煤矿中、长期防治水规划和防治水安全为目标,采用分水平、分盘区、分阶段评价的原则与方法,指导和服务于煤矿未来3~5 a生产规划,体现水文地质类型评价基础性、阶段性和指导性的根本特征。     

大海则煤矿顶板富水含水层下开采水害防治研究

为了解决顶板富水含水层下开采过程中所面临的水害问题,以侏罗纪煤田榆横北区大海则煤矿为例,通过分析矿井水文地质条件,确定了主要充水水源和充水通道,计算了防隔水煤（岩）柱留设宽（厚）度,并预测了矿井开采2号煤层时的涌水量,提出了相应的防治措施。结果表明:矿井开采2号煤层时,其主要充水水源为煤层顶板侏罗系延安组、直罗组含水层水,主要充水通道为覆岩导水裂隙带。通过计算防隔水煤（岩）柱留设宽（厚）度,分析判断其在现有2号煤层开采条件下,不会受到顶板白垩系洛河组强含水层影响。采用解析法和数值法进行矿井涌水量预测,取其算术平均值作为参考。结合矿井条件和现场实际,提出井下钻探、地球物探、水文地质监测等综合防治措施,通过预防、探查、疏排、监测等手段,共同解决矿井水害问题。     

多频并行电法在煤层顶板防治水中的应用

煤矿水害是矿井安全生产的重大灾害之一,顶板砂岩、灰岩、泥岩的电阻率差异明显,而富水性对砂岩、灰岩的电阻率影响较大,符合多频并行电法探测的地球物理依据,因此可以采用多频并行电法对工作面顶板富水情况进行探测。多频并行电法是以直流电法理论为基础,现场观测频率域电场信号,信噪比高,对工作面底板异常的平面分辨能力相对较好。通过对15309工作面顶板砂砾岩富水性探测及验证结果可知,多频并行电法是一种便捷有效的井下物探手段,能够为煤矿顶板防治水工作提供技术支撑,为煤矿安全开采提供地质保障,也可为其他煤矿类似水害探测及分析提供借鉴。     

露天矿闭坑环境地质灾害危险性分区研究

基于露天矿闭坑前后地质灾害的分析,总结出我国露天煤矿开采至闭坑前环境地质问题与灾害主要有3个方面：① 露天煤矿开采将形成深大的矿坑及废弃矸石排土场.② 露天采矿形成的矿坑边坡及排土场边坡,由于地质构造、边坡岩体、地表水与地下水作用,采矿工程活动等原因诱发一系列诸如滑坡、塌陷、泥石流、周边地面变形、地裂缝等突发性或缓变性地质灾害.③ 露天矿开采引发生态环境恶化及缓变性的灾害.提出了露天矿闭坑环境地质灾害危险性分区的方法.并根据以上研究以抚顺西露天煤矿闭坑（矿坑）环境地质灾害危险性分区为实例进行了分区,得到了符合实际的结果.     

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。