Dust-Holding Capacity and Bio-Chemical Changes of Plant Species Growing in an Around Opencast Mining Area of Bundelkhand Region of Uttar Pradesh, India

The present study has been carried out on a total of 50 available plant species to assess their dust-capturing capacity and biochemical performances in and around open cast granite mine areas of Jhansi district and Bundelkhand University campus treated as control site. Plant species existing under a polluted environment for a long time may be considered as potentially resistant species and recommended for green belt design in mining areas, especially to cope with dust pollution. Results showed the pollution level, especially of mining-originated dust particles holding capacity of leaves and effects of different biochemical parameters (Total Chlorophyll, Protein and Carotenoid) of existing plant species both from mining areas as well as from Bundelkhand University campus. Based on their performances, Tectona grandis L., Ficus hispida L., Calotropis procera Aiton., Butea monosperma Lam. and Ficus benghalensis L., etc. are highly tolerant species while Ficus infectoria L., Artocarpus heterophyllus Lam., Ipomoea purpurea L., Allianthus excelsa Roxb. and Bauhinia variegata L. are intermediate tolerant species. T. grandis had shown the highest dust-holding capacity (2.566 ± 0.0004 mg/cm2) whereas Albizia procera (0.018 ± 0.0002 mg/cm2) was found to be the lowest dust-holding capacity. Our findings also showed that the T. grandis and F. hispida have significant dust deposition with minimal effect of dust on their leaf chlorophyll (17.447 ± 0.019 mg/g and 14.703 ± 0.201 mg/g), protein (0.699 ± 0.001 mg/g and 0.604 ± 0.002 mg/g) and carotenoid (0.372 ± 0.003 mg/g and 0.354 ± 0.003 mg/g) content respectively among all selected plant species. Therefore, in the present investigation, plant species with high tolerance to high dust-holding capacity on their leaf surfaces are preferable for green corridors as open cast granite mines and their adjacent areas.

Study on the Law of the Movement and Damage to Slope with the Combination of Underground Mining and Open-Pit Mining

Under circumstances in which both underground mining and open-pit mining are employed, the mining effects of two approaches will be superposed and the mining slope will receive several induced stress fields, which makes the sliding mechanism and deformation law of slope rock mass more complicated. This paper, targeting at the east slope of Antaibao Mine with the joint employment of underground mining and open-pit mining, aims to study the moving law of the slope rock mass and the damage mechanism to the overburden of the goaf by numerical simulation. It is supposed that models of possible damage to the slope could be explored for guidance to safety-production of the mine.

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.

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.

Optimization principle of combined surface and underground mining and its applications

The pit limit optimization is discussed, which is one of the most important problems in the combined min-ing method, on the basis of the economic model of ore-blocks. A new principle of the limit optimization is put for-ward through analyzing the limitations of moving cone method under such conditions. With a view to recovering asmuch mineral resource as possible and making the maximum profit from the whole deposit, the new principle is tomaximize the sum of gain from both open-pit and underground mining. The mathematical models along the horizon-tal and vertical directions and modules for software package (DM&MCAD) have been developed and tested inTonglushan Copper Mine. It has been proved to be rather effective in the mining practice.

Quantifying the thermal damping effect in underground vertical shafts using the nonlinear autoregressive with external input(NARX) algorithm

As air descends the intake shaft, its infrastructure, lining and the strata will emit heat during the night when the intake air is cool and, on the contrary, will absorb heat during the day when the temperature of the air becomes greater than that of the strata. This cyclic phenomenon, also known as the "thermal damping effect" will continue throughout the year reducing the effect of surface air temperature variation. The objective of this paper is to quantify the thermal damping effect in vertical underground airways. A nonlinear autoregressive time series with external input(NARX) algorithm was used as a novel method to predict the dry-bulb temperature(Td) at the bottom of intake shafts as a function of surface air temperature. Analyses demonstrated that the artificial neural network(ANN) model could accurately predict the temperature at the bottom of a shaft. Furthermore, an attempt was made to quantify typical "damping coefficient" for both production and ventilation shafts through simple linear regression models. Comparisons between the collected climatic data and the regression-based predictions show that a simple linear regression model provides an acceptable accuracy when predicting the Tdat the bottom of intake shafts.

Construction of Dry Cover System for Prevention of Acid Mine Drainage at Mine Waste Dump in Open Cast Coal Mines, Indonesia

Acid Mine Drainage (AMD) which occurs when sulfide minerals are exposed to water and oxygen with an excavation is one of the serious environmental problems in the world. A dry cover system is generally constructed in waste dump for the prevention of AMD in Indonesia by virtue of low cost and availability of waste rocks for a cover layer. However, the failure of the system caused by the lack of information related to the construction of cover system in mines, which leads to AMD, has been reported recently in Indonesia. In this study, the field investigation was conducted in pit and waste dump in open cast coal mine in Indonesia with the aim of obtaining the information on the construction of a cover layer and backfilling conditions of waste rocks in the waste dump. The rock samples taken in two areas of the mine were analyzed by geochemical analysis and sequential extraction with acids. The results indicated that Net Acid Producing Potential (NAPP) of the rocks in the waste dump down to 100 cm depth in both areas was from 10 to 30 kg H2SO4/ton, suggesting that Potentially Acid Forming (PAF) was backfilled in a cover layer. The backfill of PAF was contrary to the concept of cover system, which caused the failure of constructing a cover layer. The cause of the failure was likely attributed to the shortage of cover rocks which are classified as Non Acid Forming (NAF) or the failure of proper placement of them by an operational problem in the areas. Moreover, the results of the extraction with acids suggested that the form of iron and sulfur has to be taken into account to discuss the occurrence of AMD.

基于AHP-TOPSIS的露天转地下采矿方案优选

为了确定合适的露天转地下采矿方案,建立露天转地下采矿方案综合评判指标体系,运用层次分析法(AHP)和逼近理想解的排序法(TOPSIS)基本理论建立露天转地下采矿方案优选的AHP-TOPSIS综合评判模型。从经济、技术、安全三方面综合考虑影响露天转地下采矿方案的评判指标体系,通过AHP确定各指标的权重,再结合逼近理想解的排序法原理构建AHP-TOPSIS综合评判指标模型,利用TOPSIS原理计算各方案基于评判指标的综合优越度。以黄麦岭磷矿露天转地下采矿方案优选为例,得到各拟选方案的综合优越度分别为67.39%、46.45%、52.14%,从而确定方案I为最优。研究结果表明:该方法可以综合考虑各项评价指标对评价体系的影响,并进行定量计算。

基于Delphi-TOPSIS法的露天矿采区接续方案优选

为了更加科学的优选采区接续方案,根据影响采区接续的主要因素,选取了生产剥采比稳定性与大小、累计剥采比、内排空间、采区协调性和运输功5个指标建立了露天矿采区接续优选指标体系,构建了基于Delphi-TOPSIS法的采区接续优选模型。针对霍林河露天煤矿采区划分特点,提出了采区接续方案并采用Delphi-TOPSIS模型进行优选,确定了最佳采区接续转向方案并证明了方法的准确性。

基于VWT-TOPSIS的露天转地下开采模式选择

为解决露天转地下矿山最佳开采模式选择的技术难题,综合考虑影响开采模式的动态、静态、定量、非定量指标,提出了一种基于变权重理论(VWT)和逼近理想解的排序法(TOPSIS)方法的综合评价指标体系,对4种候选的露天-地下同步开采模式进行综合评判优选。评判优选过程中,考虑到层次分析法等常规方法确定的常权用以评价各候选方案时可能会导致"状态失衡"的现象,依据变权重理论,根据各因素的组态(各因素的取值状况)的不同,适当调整其权重,以保证各因素的均衡性,进而利用TOPSIS理论计算出各方案的综合优越度,从而确定各开采模式的优越程度。将本文成果应用于某铁矿露天转地下同步开采模式选择,计算得到4种备选方案的综合优越度分别为0.087、0.767、0.898、0.723,从而确定方案Ⅲ为最优方案。其结果与工程实际中所得基本相符,在生产过程中取得良好的经济和社会效益。

倾斜煤层采空区煤柱失稳边坡稳定性研究

为了探究平庄西露天矿露井联采扰动下采空区煤柱失稳对边坡稳定性影响。采用相似模拟实验和数值模拟方法,研究平庄西露天矿不同开采阶段及采空区煤柱失稳边坡应力-位移-塑性区的演化规律及安全系数变化。研究结果表明:采空区煤柱失稳垮塌,对坡体的中上部影响较大,从而引起应力集中区域产生裂隙;在煤层采动期间边坡中部顶端达到剪切破坏的临界值,但随着采空区煤柱坍塌,坡体重心后移,剪应力减小,一定程度上抑制坡体向下滑移;采空区煤柱坍塌,边坡安全系数降低,边坡由稳定转为基本稳定状态,稳定性降低,滑坡的可能性增加。研究结果可为露天矿井工开采提供理论指导。

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。

大红山铁矿露天——地下联合开采岩移发展规律研究

地下开采产生的地表移动会影响邻近露天采场边坡的稳定性。以大红山铁矿露天—地下联合开采为例,采用微震、地表开裂观测等多种方法进行岩移监测和数据分析,探究了地下开采引起的岩体移动与地表开裂规律。首先,对历史监测数据进行了整理和分析,包括地表塌陷和裂缝的发育情况。其次,针对地下开采过程中的围岩变形特点,开展微震数据分析,获取了岩体损伤破坏信息。同时,结合矿山地质资料,统计数据得出了陷落角的变化范围。结果表明:大红山铁矿露天—地下联合开采,岩体移动发展阶段可划分为:冒落及地表贯通的岩移阶段、陷落区充分发展的岩移阶段、F2断层影响的陷落角非对称发育阶段、废石充填与深部开采下的岩移阶段。西北部陷落角发育范围为75°~81°、东南部陷落角发育范围为65°~82°。研究可为类似地质及工程条件矿山岩移发展规律分析提供一定参考。

某金矿露天转地下开采境界顶柱合理厚度研究

某金矿自标高1 385 m以下将由露天开采转为地下开采,拟采用上向进路充填采矿法进行开采,为了避免露天与地下同时开采造成的相互影响,实现矿山生产的平稳过渡,对境界顶柱的合理厚度进行了研究。在相关室内试验的基础上,应用K.B.鲁别涅依特公式、“三带”理论和工程类比法计算出境界顶柱的合理厚度取值范围;采用Flac^(3D)软件对不同境界顶柱厚度进行数值模拟,确定该矿山露天转地下开采境界顶柱的合理厚度。结果表明:矿山原生矿和氧化矿区域进行地下开采时需分别留设20 m和25 m的境界顶柱厚度,此时地下开采对露天边坡的影响最小且采场整体趋于稳定,能满足矿山安全生产的要求。研究结果可为矿山设计提供理论依据。

露天地下楔形转接过渡诱导冒落控制边坡岩移危害技术研究

露天地下楔形转接过渡模式的安全管控是利用崩落法开采挂帮矿形成的塌陷坑阻止边坡岩移威胁露天采场,但地采扰动下的高陡边坡破坏过程不易控制,因而制约了楔形转接过渡模式在大型深凹露天矿山中的应用。针对上述问题,结合极限平衡分析方法,揭示出崩落法开采扰动下的高陡边坡渐进破坏规律,提出了边坡滑移体体积计算方法,以及通过调控回采顺序控制边坡滑移进程以实现塌陷坑完全承接边坡滑移体的边坡岩移危害控制技术。研究表明:边坡岩体不会随挂帮矿向下开采而发生持续破坏,只有当挂帮矿开采至关键分段时,边坡岩体受力状态超过极限平衡状态才发生滑移破坏,可通过滞后回采关键分段上盘三角矿延缓边坡滑移,以及通过滞后回采关键分段下盘矿体和采用下向阶梯状回采工作面增大塌陷坑容积,最终实现塌陷坑有序承接边坡滑移体。研究成果完善了大型深凹露天矿楔形转接过渡的安全管控方法,提高了楔形转接过渡模式的适用性。

倾斜矿体多采空区顶板破坏与冒落机理分析

排山楼金矿上部矿体露天转地下阶段应用空场法开采,采空区已用诱导冒落+地表废石充填塌陷区的方法进行了治理;下部矿体进入海棠山国家自然保护区范围,地表不允许塌陷,但由于矿石品位低,继续沿用传统充填法势必造成矿床开采效率低、生产成本高、矿山经济效益差等问题。以地表保护区下低品位矿体充填法安全高效开采为工程背景,结合RG井下电视系统监测结果总结了顶板上覆岩层裂隙分布与发展规律,分析了应力平衡拱与冒落拱演化机理,提出了稳定冒落拱的形成条件。基于现场监测与岩石力学参数试验结果,通过FLAC^(3D)数值模拟方法研究了倾斜多空区贯通与拉底过程中顶板破坏与冒落机理,探明了顶板冒落过程中围岩的应力和位移演化规律,以及诱发冒落的主导因素,并提出了基于地表安全性的冒落进程控制技术。研究成果可为该矿开发既满足地表保护需求又能低成本高效开采的工艺技术提供理论参考,对于类似矿山的采矿方法设计也有一定的借鉴意义。

基于数值模拟的露天转地下开采关键参数优化研究

基于某露天铁矿转入地下开采时矿体上下盘围岩需要被保护的特殊情况,结合深部矿体赋存特征,采用FLAC^(3D)对地下回采关键参数进行数值模拟分析。研究发现,地下开采矿体内上盘回采单元采场顶部与上盘边界之间预留的矿柱水平宽度对采场空区及上盘围岩稳定性有较大影响。为实现深部资源高效安全开采,推荐上盘回采单元采场顶部预留的矿柱水平安全宽度为10 m,并采用盘区间隔回采的顺序,开采完成应尽快进行充填作业,以控制采场顶板沉降。

露天转地下开采露天边坡稳定性数值模拟分析及研究

某金属矿山原采用露天开采,随着露天开采资源的逐渐枯竭,现转为地下开采,考虑到地下开采对露天边坡的稳定性必然存在一定的影响。设计在露采最终边坡一侧保留50 m宽度的保安矿柱,以保证露天最终边坡的稳定性。采用数值计算与强度折减相结合的方法,选取具有代表性的3条剖面线,建立边坡计算模型,对边坡原始状态、空场法开采和充填法开采后3种不同工况下的露天边坡模型进行稳定性计算并确定相应工况下边坡的稳定性。最终得出当采用强度不小于1 MPa充填体进行充填法开采计算时,3个典型边坡的安全系数均大于1.15,处于稳定状态。

“十三五”期间非煤矿山安全生产情况及未来对策

非煤矿山的开采是我国的基础产业,同时也是经济发展的重要支柱,在许多新兴产业发展中扮演着越来越重要的角色。随着矿产资源开发强度的不断加大,非煤矿山行业也产生了较多典型的安全生产事故,为探讨我国非煤矿山安全存在的主要问题,搜集了我国“十三五”期间(2016—2020年)非煤矿山安全生产数据,分别从事故发生区域、事故类型、事故发生时间、开采方式、矿种类型、所属行业等方面进行了分析,得出以下结论:1)我国非煤矿山中小型矿山以40%左右的产能酿成了超过90%的事故,安全生产基础总体薄弱;2)如内蒙古、湖南、广西等重点区域安全生产形势仍严峻;3)地下矿山的事故起数和死亡人数均占非煤矿山事故总量的50%以上,以冒顶坍塌为主的10类事故死亡人数较大。导致这种情况的主要原因是我国非煤矿山企业安全管理能力仍然较弱、非煤矿山安全生产监管监察能力仍需提升、我国非煤矿山智能化建设仍处于初级阶段,事故重灾区机械化、自动化、智能化建设程度总体较低。只有进一步推进非煤矿山企业及监管监察部门装备设备的智能化水平的提升,从矿山全生命周期中的各个生产流程及环节进行改造升级,才能实现“十四五”时期安全生产质量的进一步提升。

基于MatDEM的露天转地下房柱法开采覆岩与边坡失稳规律研究

随着露天矿山转入地下开采,研究二次扰动后覆岩与边坡系统的稳定性显得尤为重要。以江西某大型露天转地下房柱法开采矿山为研究背景,使用MatDEM离散元软件建立了数值模拟模型,计算并分析了房柱法开采扰动下覆岩与露天边坡的位移、应力以及动能等参数的变化规律。结果表明:随着开采空区形成,采场覆岩形成了以开采区域为中心的椭圆形应力降低区,该区域岩层发生了显著的破坏,并且沿着开采推进方向移动。采场顶板的应力变化随开采进程表现出应力集中—应力增大—应力重构—应力平衡4个阶段。地下开采使得采场覆岩以及露天边坡产生了较大位移,覆岩的岩移面积和岩移动能均较边坡的更大,覆岩的变化表现出更加敏感的特性。研究结果可以为相似矿山的开采设计提供借鉴。