Quantitative hazard assessment system(Has-Q) for open pit mine slopes

Rock slope hazard assessment is an important part of risk analysis for open pit mines.The main parameters that can lead to rock slope failures are the parameters traditionally used in geomechanical classifications,the slope geometrical parameters and external factors like rainfall and blasting.This paper presents a methodology for a hazard assessment system for open pit mine slopes based on 88 cases collated around the world using principal components analysis,discriminant analysis and confidence ellipses.The historical cases used in this study included copper,gold,iron,diamond,lead and zinc,platinum and claystone mines.The variables used in the assessment methodology are uniaxial compressive strength of intact rock;spacing,persistence,opening,roughness,infilling and orientation of the main discontinuity set;weathering of the rock mass;groundwater;blasting method;and height and inclination of the pit.While principal component analysis was used to quantify the data,the discriminant analysis was used to establish a rule to classify new slopes about its stability condition.To provide a practical hazard assessment system,confidence ellipses were used to propose a hazard graph and generate the HAS-Q.The discriminant rule developed in this research has a high discrimination capacity with an error rate of 11.36%.

Stability analysis of the sliding process of the west slope in Buzhaoba Open-Pit Mine

To study the stability of the west slope in Buzhaoba Open-Pit Mine and determine the aging stability coefficient during slide mass development, the deformation band of the west slope and the slide mass structure of the 34,600 profile are obtained on the basis of hydrology, geology, and monitoring data.The residual thrust method is utilized to calculate the stability coefficients, which are 1.225 and 1.00 under sound and transfixion conditions, respectively. According to the rock damage and fragmentation and the principle of mechanical parameter degradation, the mechanical models of the slide mass development of the hard and soft rock slopes are established. An integrated model for calculating the slope stability coefficient is built considering water, vibration, and other external factors that pertain to the structural plane damage mechanism and the generating mechanism of the sliding mass. The change curve of the stability coefficient in the slide mass development is obtained from the relevant analyses,and afterwards, the stability control measures are proposed. The analysis results indicate that in the cracking stage of the hard rock, the slope stability coefficient decreases linearly with the increase in the length Lbof the hard rock crack zone. The linear slope is positively correlated to rock cohesion c. In the transfixion stage of the soft rock, the decrease speed of the stability coefficient is positively correlated to the residual strength of the soft rock. When the slope is stable, the stability coefficient is in a quadratic-linear relationship with the decreased height Dh of the side slope and in a linear relationship with anchoring force P.

Cut slope reinforcement technique in open-pit mines

The design and practice in supporting the cut slope of an open-pit mine wereintroduced, in which the high pressure grouting method was used in reinforcing the weak formation inthe slopes. Based on a detailed geological survey of the slope, a theoretical analysis was carriedout, and the design parameters were proposed, where the Tresca or Mohr-Coulomb yield criteria wasemployed. A patent technology, named 'Technology of high pressure and multiple grouting in differentlevels within a single hole', was employed in the construction. Anchor bars were also installed asgrouting proceeds. This method combines anchoring and grouting comprehensively and was foundsuccessful in practice.

Reliability Assessment of an Open Pit Slope on Bong Iron Ore Mine

Slope stability on Bong mine is crucial for securing a balance in the gross national product of Liberia. The mine is being operated using conventional open pit methods with slope angles optimally designed to maximize ore stripping quantity. However, a working slope has displayed signs of uncertainty. The overall inclination of the slope is 56°, and the proposed maximal excavation is 315.42 m, but current depth in ore is approximately 50%. Based on the study of slope geological characteristics, the physical and mechanical parameters of rock mass and the geometrical calculation of stoping, the study is tailored on the mechanism of inspecting stress-strain behavior in response to seasonal variation of rock moisturization as a more suitable means of stope slope stability analysis in this case. This study took full account of local rainfall and other meteorological conditions. Slope stability is investigated via stereographic projections and stability assessment using the Shear Strength Reduction (SSR) method based on FLAC (Fast Lagrangian Analysis of Continua) numerical modeling technique in three dimensions to predict the stress-strain behavior of the open-pit slope and evaluate its stability state. Global stability has been analyzed under natural and saturated conditions and it is found that the slope is critically stable and needs proper attention.

Application of open-pit and underground mining technology for residual coal of end slopes

Given the conditions of residual coal from the boundary of a flat dipping open-pit mine,which uses strip areas mining and inner dumping with slope-covering,we propose an open-pit and underground integrated mining technology for residual coal of end slopes.In the proposal a conveyance road and ventilation conveyance near the slope are built,corresponding to the pit mining area and the surface coal mine dump,as well as an interval haulage tunnel and air-inlet tunnel.The outcome shows that such mining method may reduce the effect to slope stability from underground mining,it does not affect the dumping advance and has a high recovery rate of residual coal resources.The working face is timbered by single hydraulic props,transported by a scraper conveyor and supported by coal walls.This method of mining is one of layered top coal caving,with high resource recovery,low production cost where positive economic benefit can be realized.

SICOMINES铜钴矿含尾砂高大边坡稳定性分析及治理思路

刚果(金)SICOMINES铜钴矿M坑北部上部局部边坡处于不稳定状态,可能存在滑坡风险。本文采用二维极限平衡分析方法,对北部含尾砂高大边坡稳定性进行了边坡稳定性计算和分析,提出了整体边坡角不应大于31°的优化建议,并为后续边坡治理提供了参考。

基于Rhino和3Dmine的露天煤矿边坡三维数值模型构建

针对露天煤矿边坡人工地表起伏突出和自然地层相对平滑的几何特点,以Rhino和3Dmine软件为过渡平台,以Nurbs和DTM曲面差值处理方法分别对露天煤矿地表和地层进行处理,最终在Rhino中完成露天煤矿边坡三维数值模型网格的划分及输出,实现兼顾人工地表特征和自然地层特征的露天煤矿边坡三维数值模型的全程可视化构建。工程案例分析结果表明:此方法所构建的数值模型可充分体现露天煤矿三维边坡的几何特点。

Effects of Sublevel Open Stope Underground Mining on Surface and Open Pit Slopes

Underground mining is an economically viable option for exploiting ore reserves deemed uneconomic after open pit mining. However, underground development can have adverse effects on the above existing open pit slope walls. As a goal of this paper, identification and assessment of potential slope instabilities prior to underground development is crucial for safe and sustainable mining. Towards goal achieving, this paper gives a comprehensive parametric study to investigate the influence of sublevel open stope (SLOS) underground mining on the surface and open pit slope walls. By means of numerical simulation, the SLOS design is tried against the existing open pit followed by adjustments of important slope parameters which are overall slope height (OSH) and overall slope angle (OSA). We found that underground mining may induce slope failure, particularly on the hangingwall side of the pit. Subsidence is prominent on the hanging wall and the surface, whereas, the uplift dominates the footwall and pit bottom. Pit wall closure is observed during underground mining. Although the assigned dimensions in the parametric study show a negligible effect of OSH and OSA, the high OSH experience low subsidence in comparison with low OSH. Overall, the results demonstrate that the slope walls on the hanging wall side are mostly affected by the underground mining and high-stress concentration prevails near slope toes and pit bottom. Additionally, slope deformation decrease from pit bottom towards the slope crest and surface. The results of this study add knowledge to open pit and underground mining interaction.

新工科背景下基于OBE理念的露天矿边坡稳定课程教学改革与实践

在新工科建设背景下,我国高等院校提出培养具备实践能力和创新能力的工程人才的新要求,采矿工程专业的课程教学也需与时俱进。针对目前传统教育存在的问题,基于OBE理念对露天矿边坡稳定课程改革进行思考,从修订教学目标、教学内容重构、教学策略改革和多元化新型评价体系四个方面,对露天矿边坡稳定进行课程改革。通过以上改革策略的实施,以期提高学生在新工科背景下露天矿边坡稳定课程中的学习效果和综合能力,为培养适应新工科要求的优秀采矿类人才提供参考和借鉴。

基于渗流作用下含断层的露天矿边坡稳定性的数值模拟研究

为研究含断层露天边坡在渗流作用下的稳定性问题,采用FLAC3D数值模拟技术构建断层作用下的滑体力学模型,获得顺倾层状边坡分条稳定系数表达式,进而对渗流作用下含断层边坡稳定性进行数值模拟分析。对岩体强度的弹性模量、内聚力、内摩擦角和岩体抗拉强度等4种影响因素进行敏感性分析,通过分析这4种因素在不同工况下边坡的位移、应力、应变和安全系数,得出了各参数的敏感性分析曲线。从敏感性分析曲线可知,岩体的内聚力对边坡稳定性的影响最大,弹性模量对边坡稳定性的影响最小。开挖不同阶段边坡稳定性的主要影响因素存在差别,其中,前期以断层为主,后期则逐渐转化为渗流作用。该研究为今后露天矿边坡稳定性分析提供了科学依据,对于边坡稳定性分析具有重大的工程实际意义。

露天煤矿排土场边坡植被恢复群落稳定性研究

为了揭示露天煤矿排土场边坡植被恢复群落稳定性的动态特征和变化模式,以内蒙古北电胜利露天煤矿4个排土场为研究对象,选取Shannon-Wiener多样性指数、Margalef丰富度指数、Pielou均匀度指数和Simpson优势度指数、植被盖度、植被高度、地上和地下生物量8个指标,构建了基于群落结构稳定性与群落功能稳定性的排土场边坡植被恢复群落稳定性评价体系,采用综合评价法对处于人工植被恢复中的内排土场和恢复年限分别为4 a、5 a、8 a的沿帮排土场、南排土场和北排土场的南、北方向边坡植被恢复群落稳定性进行综合评估,并对群落稳定性因子与土壤含水量、有机质、全氮、全磷、全钾等环境因子间关系进行分析,探究影响排土场边坡群落稳定性的影响因素。结果表明:(1)随着恢复年限的增加,边坡植被群落稳定性整体呈稳步上升趋势,但与草原站背景值相比,其综合评价指数处于较不稳定或不稳定状态。(2)随着恢复年限的增加,排土场边坡群落稳定性由结构稳定性主导转向功能稳定性主导。恢复初期受人工影响,物种多样性提高,结构稳定性较高,随着时间的推移,结构稳定性波动下降,功能稳定性上升,其中地下生物量增长迅速,生物量向地下转移,进而形成矿区特有的植物群落结构稳定与功能稳定转变特征。(3)从坡向来看,随着恢复年限的增加,边坡群落稳定性逐渐由南坡优于北坡转变为北坡优于南坡。(4)南坡的结构稳定性与环境因子的相关性较高,而北坡的功能稳定性与环境因子相关性较高,表明不同坡向的群落采用了不同的响应策略以适应环境的变化,丰富的有机质和全氮含量对排土场边坡群落功能性稳定性会产生积极影响。

基于3DMine软件的露天矿山开采境界圈定

合理的露天开采境界直接关系到矿山经济效益,而境界的圈定是一项非常复杂的工作。根据某矿山的开采技术条件,利用3DMine软件建立了矿体实体模型和经济模型,并进行了露天开采境界圈定,通过不断优化,得出该矿山的最优露天开采境界。选择底标高为1215 m的露天境界为最终的优化境界,考虑到露天坑底最小宽度及台阶坡度影响,选择1245 m为最低平台高度。

基于变权理论的露天矿边坡稳定性GRA-TOPSIS评价模型研究

为使露天矿边坡稳定性评估更加科学合理,进一步提高评估结果可靠性,迫切需对现有评价模型进行优化和改进。基于变权理论、灰色关联理论(GRA)和逼近理想解法(TOPSIS),提出了露天矿边坡稳定性改进GRA-TOPSIS评价模型。从地质、环境、工程等3个方面,选取了12个典型影响因素,构建了露天矿岩质边坡稳定性综合评价指标体系;运用变权理论确定指标权重,通过计算灰色关联贴近度,实现露天矿岩质边坡稳定性综合评价。以3座矿山(K1-K3)为例,验证评价模型的适用性。结果显示:3座露天矿边坡稳定性排序为K3>K2>K1,稳定性等级分别为Ⅲ级、Ⅱ级和Ⅱ级,与边坡实际相符;通过对比改进GRA-TOPSIS模型与单独使用GRA、TOPSIS模型以及其他模型的评价结果,验证了改进GRA-TOPSIS综合评价模型在露天矿边坡稳定性评估方面的准确性和优越性,体现了研究价值,可为露天矿边坡稳定性评估提供新思路。

露天矿高陡复杂边坡软弱岩层组“坐落-滑移式”破坏模式研究

边坡稳定性问题随露天矿开采的进行不断突出,而边坡软弱岩层严重影响边坡稳定性。大量工程实例显示,露天矿含软弱岩层组的高陡复杂边坡失稳模式通常为“坐落-滑移式”破坏。为明晰露天矿高陡复杂边坡软弱岩层组“坐落-滑移式”破坏模式的破坏机理,以某露天矿为例,提出一种针对露天矿含软弱岩层组高陡复杂边坡的综合分析方法。研究结果表明:采用工程地质分析、传统极限平衡方法和数值模拟分析相结合的综合分析方法,针对该类型复杂边坡可发挥不同分析方法的优势,较全面地从地质自然环境条件、定性定量方面、应力应变角度分析边坡破坏机理及模式,总结归纳出含软弱层组露天矿高陡复杂边坡“坐落-滑移式”破坏的“坐落-滑移-剪出”三段式破坏特征,为其他类似复杂边坡稳定性的分析和防治提供思路和手段。

齐大山铁矿东帮边坡空间形态优化

针对齐大山铁矿东帮边坡空间形态优化问题,在分析边坡工程地质条件的基础上,将极限平衡法与数值模拟法相结合,评价原设计到界边坡稳定性,优化设计到界边坡的形态参数,探讨追踪距离对边坡三维稳定性的影响规律。研究结果表明:采用逐水平优化方法设计的到界边坡角为46°,每阶段的边坡二维稳定性系数均满足安全储备系数要求;边坡的三维稳定性系数与追踪距离呈负相关指数函数关系,当追踪距离为50 m时,齐大山铁矿东帮到界边坡角可设计为48°,整体边坡角提高了2°,经济效益显著。

露天矿开采过程边坡加固技术研究与应用

针对铜山口铜矿露天开采过程中边坡稳定性的关键问题,系统研究边坡加固技术及其应用。通过分析铜山口铜矿的工程概况、边坡稳定性理论基础及影响因素,提出针对性的加固原则、策略和技术措施。采用综合加固方法,如爆破振动控制、排水系统设计、弱层加固与边坡整形、增设平台与支护结构等,可以提高边坡的稳定性,确保开采安全,提高生产效率。以及对加陡边坡的可行性进行探讨,为铜山口铜矿的边坡加固与优化设计提供了科学依据。

点荷载试验在典型露天采场超高边坡工程地质勘察中的应用

夏日哈木镍钴矿山拟建大型超高边坡露天采场,需进行边坡工程地质勘察工作。岩石抗压强度是重要的工程地质参数,如何在青藏高原山区快速获得各类岩石的单轴抗压强度等参数非常关键,尤其是各类难以进行室内压缩试验的风化或蚀变岩石。本次在野外现场采用济南矿岩HDH-1型岩石点荷载仪对矿区内各类岩石进行点荷载试验,并通过前人总结的点荷载强度与单轴抗压强度转换公式计算出了各类岩石的单轴抗压强度及层状(条带状)岩石的各向异性指数。本次点荷载试验克服了昆仑山区岩石测试加工工序复杂、周期较长、成本高等因素,且适用于风化层、蚀变带内不易进行室内压缩试验的岩石,是一种间接测量估算岩石相关强度参数的快捷方法,对以后西部山区的工程地质勘察工作具有较为广泛的借鉴作用。

边坡监测与治理技术在高寒矿区露天煤矿生态修复中的应用研究

边坡治理是露天矿山生态修复中的重要内容之一。以青海木里矿区聚乎更区为例,针对高寒矿区露天煤矿的边坡问题识别、监测和治理开展了系统研究,通过遥感、物探、钻探及地表测量等手段研究了矿区内不稳定边坡发育特征及稳定性。研究结果表明:建立了以遥感技术为核心,辅以常规的地表监测、地质调查、物探及钻探等手段的“天空地时”一体化不稳定边坡探查监测体系,确定矿区内不稳定边坡发育特征及稳定性,为矿山修复治理针对性开展边坡治理提供依据;采用高危渣山降高减载和边坡减坡治理技术,对边坡台阶进行清坡处理,消除浮石和崩塌等灾害,对渣山削坡卸载,使采坑边坡和渣山边坡达到稳定状态;并以聚乎更4号井南渣山为例,根据高密度电法探测和钻探验证,识别出了常年冻土上限和渣土层与原采坑基岩界线两个滑移面,确定后缘载荷过大是导致滑坡的主要因素,采取“后缘降高减载+边坡减坡+水系连通+综合监测”的治理方案,治理后既消除了对边坡前缘的载荷,又为后期植被复绿提供了稳定的立地条件。多期次动态监测表明边坡后缘已趋于稳定;边坡监测及治理技术在木里矿区生态修复治理中得到广泛使用,治理后的渣山边坡坡度控制均小于26°,有效消除了不稳定边坡对修复治理的影响,保障了矿山生态修复治理成效。

基于SSA-BP的露天矿山边坡位移变形预测

针对传统的BP神经网络在预测露天矿山边坡位移变形时存在的局限性,构造了一种基于麻雀搜索算法(SSA)和BP神经网络相结合的边坡位移变形预测模型,先利用麻雀搜索算法对传统的BP神经网络进行权值与阈值的优化,再将麻雀搜索算法优化后的BP神经网络算法(SSA-BP)运用于露天矿山边坡位移的预测。为了验证算法的可行性,将SSA-BP预测模型与WOA-BP、BP以及Elman预测模型针对露天矿山边坡位移变形量的预测结果进行比较。实验结果表明:SSA-BP预测模型针对露天矿山边坡位移变形量的预测相比其他三种模型,其迭代速度快、寻优能力强;通过预测精度评价指标来看,SSA-BP算法的R2、RMSE、MAPE、MAE、MSE明显优于另外三组算法。为露天矿山边坡位移变形预测提供了一种新的思路和方法。

某钨矿露地联采关键地压灾害监测预警研究

某钨矿形成了露地联采的开采局面,面临着井下群采空区与隔离间柱稳定性、露采边坡稳定性、露地相互影响等关键地压灾害问题。设计建设了最先进的66通道微震监测系统、测量机器人与边坡雷达等地压监测预警系统。文章详细介绍了一次典型的岩体失稳垮塌的成功预警案例。上述综合性的地压监测手段将为矿山安全生产提供重要的技术支撑。