Mechanism,prevention,and control of mining-induced dynamic disasters in underground metal mines in China:Challenges and solutions

Metal mineral resources play an indispensable role in the development of the national economy.Dynamic disasters in underground metal mines seriously threaten mining safety,which are major scientific and technological problems to be solved urgently.In this article,the occurrence status and grand challenges of some typical dynamic disasters involving roof falling,spalling,collapse,large deformation,rockburst,surface subsidence,and water inrush in metal mines in China are systematically presented,the characteristics of mining-induced dynamic disasters are analyzed,the examples of dynamic disasters occurring in some metal mines in China are summarized,the occurrence mechanism,monitoring and early warning methods,and prevention and control techniques of these disasters are highlighted,and some new opinions,suggestions,and solutions are proposed simultaneously.Moreover,some shortcomings in current disaster research are pointed out,and the direction of efforts to improve the prevention and control level of dynamic disasters in China’s metal mines in the future is prospected.The integration of forward-looking key innovative theories and technologies in the abovementioned aspects will greatly enhance the cognitive level of disaster prevention and mitigation in China’s metal mining industry and achieve a significant shift from passive disaster relief to active disaster prevention.

Developments and prospects of microseismic monitoring technology in underground metal mines in China

Microseismic monitoring technology has become an important technique to assess stability of rock mass in metal mines.Due to the special characteristics of underground metal mines in China,including the high tectonic stress,irregular shape and existence of ore body,and complex mining methods,the application of microseismic technology is more diverse in China compared to other countries,and is more challenging than in other underground structures such as tunnels,hydropower stations and coal mines.Apart from assessing rock mass stability and ground pressure hazards induced by mining process,blasting,water inrush and large scale goaf,microseismic technology is also used to monitor illegal mining,and track personnel location during rescue work.Moreover,microseismic data have been used to optimize mining parameters in some metal mines.The technology is increasingly used to investigate cracking mechanism in the design of rock mass supports.In this paper,the application,research development and related achievements of microseismic technology in underground metal mines in China are summarized.By considering underground mines from the perspective of informatization,automation and intelligentization,future studies should focus on intelligent microseismic data processing method,e.g.,signal identification of microseismic and precise location algorithm,and on the research and development of microseismic equipment.In addition,integrated monitoring and collaborative analysis for rock mass response caused by mining disturbance will have good prospects for future development.

Cloud model-clustering analysis based evaluation for ventilation system of underground metal mine in alpine region

Ventilation system is significant in underground metal mine of alpine region.Reasonable evaluation of ventilation effectiveness will lead to a practical improvement for the maintenance and management of ventilation system.However,it is difficult to make an effective evaluation of ventilation system due to the lack of classification criteria with respect to underground metal mine in alpine region.This paper proposes a novel evaluation method called the cloud model-clustering analysis(CMCA).Cloud model(CM)is utilized to process collected data of ventilation system,and they are converted into cloud descriptors by CM.Cloud similarity(CS)based Euclidean distance(ED)is proposed to make clustering analysis of assessed samples.Then the classification of assessed samples will be identified by clustering analysis results.A case study is developed based on CMCA.Evaluation results show that ventilation effectiveness can be well classified.Moreover,CM is used alone to make comparison of evaluation results obtained by CMCA.Then the availability and validity of CMCA is verified.Meanwhile,difference of CS based ED and classical ED is analyzed.Two new clustering analysis methods are introduced to make comparison with CMCA.Then the ability of proposed CMCA to meet evaluation requirements of ventilation system is verified.

Dynamic optimization of cutoff grade in underground metal mining

In order to maximize the overall economic gain from a metal mine operation, selection of cutoff grades must consider two important aspects: the time value of money and the spatial variation of the grade distribution in the deposit. That is, cutoff grade selection must be dynamic with respect to both time and space. A newly developed method that fulfills these requirements is presented. In this method, the deposit or a portion of it under study is divided into "decision units" based on the mining method and sample data. The statistical grade distribution and the grade-tonnage relationship of each decision unit are then computed based on the samples falling in the unit. Each decision unit with its grade-tonnage relationship is considered as a stage in a dynamic programming scheme and the problem is solved by applying a forward dynamic programming based algorithm with an objective function of maximizing the overall net present value (NPV). A software package is developed for the method and applied to an underground copper mine in Africa.

Multidisciplinary design optimization on production scale of underground metal mine

In order to ensure overall optimization of the underground metal mine production scale, multidisciplinary design optimization model of production scale which covers the subsystem objective function of income of production, safety and environmental impact in the underground metal mine was established by using multidisciplinary design optimization method. The coupling effects from various disciplines were fully considered, and adaptive mutative scale chaos immunization optimization algorithm was adopted to solve multidisciplinary design optimization model of underground metal mine production scale. Practical results show that multidisciplinary design optimization on production scale of an underground lead and zinc mine reflect the actual operating conditions more realistically, the production scale is about 1.25 Mt/a (Lead and zinc metal content of 160 000 t/a), the economic life is approximately 14 a, corresponding coefficient of production profits can be increased to 15.13%, safety factor can be increased to 5.4% and environmental impact coefficient can be reduced by 9.52%.

Movement scope of strata based on fuzzy BP neural network in underground metal mines

A prediction method of strata movement in underground metal mines is put forward, in which fuzzy BP neural network is applied. The results show that there is a strong nonlinear relation between the selected factors and strata movement angle, the anticipant and the actual output results are very similar. It is proved that the numerical value of movement angle is correlated with the selected factors in theory. The scope of strata and surface movement due to mining can be predicted. This research provides a thought to study the movement scope of strata due to mining.

Health risk assessment of heavy metal pollution in groundwater of a karst basin,SW China

To investigate the presence of metal elements and assess their health risk for the populace in the Nandong Underground River Basin(NURB),we conducted an analysis of eleven common heavy metals in the water body.A Health risk assessment(HRA)model was employed to analyze 84 water samples from the NURB.The detection results revealed the following order of heavy metals concentrations:Fe>Al>Mn>Zn>As>Cd>Pb>Cr>Ni>Cu>Hg.Correlation analysis indicated a certain similarity in material source and migration transformation among these eleven metal elements.Our study identified that the health risks for local residents exposed to metal elements in the water of NURB primarily stem from carcinogenic risk(10^(−6)–10^(−4)a^(−1))through the drinking water pathway.Moreover,the health risk of heavy metal exposure for children through drinking water was notably higher than for adults.The maximum health risks of Cr in both underground and surface water exceeded the recommendation standard(5.0×10^(−5)a^(−1))from ICRP,surpassing the values recommended by the Swedish Environmental Protection Agency,the Dutch Ministry of Construction and Environment and the British Royal Society(5.0×10^(−6)a^(−1)).The results of the health risk assessment indicate that Cr in the water of NURB is the primary source of carcinogenic risk for local residents,followed by Cd and As.Consequently,it is imperative to control these three carcinogenic metals when the water was used as drinking water resource.

Underground void filling by cemented mill tailings

Underground mining always create voids.These voids can cause subsidence of surface.So it is always a demand to fill the void in such a manner that the effect of underground mining can be minimized.Void filling using mill tailings especially in metal mining is one of the best techniques.The tailings produced in milling process have traditionally been disposed in tailing ponds creating a waste disposal and environmental problems in terms of land degradation,air and water pollution,etc.This disposal practice is more acute in the metal milling industry where the fine grinding,required for value liberation,results in the production of very fine tailings in large percentage.This paper includes discussions on the effectiveness of different paste mixes with varying cement contents in paste backfilling operations.The results revealed that material composition and use of super plasticizer strongly influenced the strength of cemented backfill.

Environmental Contamination by Industrial Effluents and Sludge Relative to Heavy Metals

Oman is located in the tropic of Cancer with extremely hot temperatures ranging between 15°C-25°C in winter and 30 - 48 in the summer with low rainfall. Most of the water source is desalinated seawater. Recycling of sewage effluent is a common practice used for farming, public parks and industry. The dried sludge product is used as fertilizer. The highly concentrated sludge with heavy metals is either incinerated or buried in landfills. Heavy metals were analyzed and compared in treated sewage effluent (TSE), slurry sludge, dried sludge, landfill and underground water. Heavy metal concentrations were analyzed using the inductive coupled plasma optical emission spectrometer (ICP-EOS). All samples contained the same heavy metals with different concentrations. The heaviest concentrations were Zn, Cu, Cr and Ni with traces of V, Cd, Pb and Ba. TSE and sludge were the main sources of landfill and underground water contamination. Due to water evaporation, heavy metals concentrations in sludge were higher compared to TSE and underground water. Dried sludge and landfill contained higher concentrations than the others. Based on this investigation, it appears that the source of heavy metals is from TSE originated mainly in industries. If the infiltration of heavy metals to soil and underground water continues, it will be a serious environmental and health problem in the future.

Metal derivative(MD)/g-C_(3)N_(4) association in hydrogen production:A study on the fascinating chemistry behind,current trend and future direction

Metal derivative/graphitic carbon nitride(g-C_(3)N_(4))association is found promising in providing sustainable hydrogen production by photocatalytic water splitting process.Number of works reported on the synthesis and application of various metal based g-C_(3)N_(4)composites are increasing day by day.Mechanism of charge separation varies according to the metal candidate that gets couple with g-C_(3)N_(4).The present article thus explores the interesting chemistry behind various metal based heterojunction and demonstrates the charge separation route.A thorough investigation has been done on the current research trend in the area.As many metal free g-C_(3)N_(4)composites are reported nowadays as an alternative to metal derivatives,here compares metallic and metal free derivatives of g-C_(3)N_(4)based on four critical requirements of an industrial catalyst,ie,activity,stability,cost and toxicity.Challenges and future direction in the area are also discussed with significance.The systematic discussion and schematic illustration of charge transfer process in different heterojunctions with reference to the reported systems,given in the article can definitely contribute to the design and development of more efficient g-C_(3)N_(4)based heterojunctions in future for hydrogen production application.

地下金属矿开采装备短间隔智能调度体系研究

作为矿山生产管理的重要内容,生产调度优化与管控可以充分利用产能、降低开采成本,因此成为现代矿山降本增效的有效手段。通过精细化调度管理和智能决策方法,实现复杂条件下的开采装备高效协同作业,充分提高调度管控效率和矿山生产能力,是现阶段矿山开采装备智能调度需要解决的关键问题。以地下金属矿山开采装备调度过程为研究对象,以提高开采装备的作业效率和生产能力为目的,研究了开采装备智能调度管控模式、决策支持算法和集成化应用。针对现代地下金属矿生产实时化、精准化与智能化管控的新需求,提出了开采装备短间隔智能调度新模式,形成了以“任务分解—任务配置—运输配置—作业指令—响应修正—分析反馈”为特征的短间隔闭环调度方案。设计了包括开采装备任务配置与调度优化算法、面向多级动态配矿的矿石流优化算法、无轨装备集群调度控制优化算法的智能化决策支持算法库,实现由人工经验到智能决策的转变。将开采装备短间隔智能调度体系进行综合示范应用,满足了现代矿山精细化管控和智能化决策需求。研究成果对于地下矿山开采装备作业过程的精细化管控与开采效率提升具有指导意义,同时也为现代地下金属矿山的生产调度管理提供了理论和方法支撑。

地下金属矿山智能建设系统架构设计与应用

金属矿山智能化是矿业高质量发展的核心保证,建立健全地下金属智能矿山系统架构,构建标准体系、强化基础设施、加快智能生态演进、深化产业融合应用、提升安全保障是金属矿山地下开采智能化的基础和指南。针对当前地下金属矿山智能建设尚未有成系统的架构和模式,缺乏顶层统筹规划设计,易发生重复性建设等问题,本文提出一套成熟的系统架构和技术路径,并在实际应用中取得良好的成效,提升了地下金属矿山智能化标准的整体支撑作用,促进了金属矿产行业发展。

芯轴式封隔器金属密封设计及密封性能分析

针对油页岩、页岩油、重质油和富油煤等非常规油气资源采用地下原位改质技术开采,井下存在高温、高压和腐蚀环境,常规封隔器及其密封不能满足工程要求的问题,设计了一种芯轴式金属对金属密封的井下封隔器,密封副采用耐高温和腐蚀的Inconel 625材料,其中密封座采用金属陶瓷涂层结构。进行了封隔器坐封密封原理试验。试验结果表明,封隔器能在油套大环空间隙形成密封,且密封能力随着坐封载荷的增加而增大。基于密封接触能原理,应用ANSYS软件模拟了井下封隔器的密封性能,并对其影响因素进行研究。研究结果表明:涂层厚度和涂层弹性模量对密封能力影响不显著;芯轴密封面椭圆率和过盈量对密封能力影响较大,起决定性作用。基于密封副高温、持久载荷作用下许用应力低和密封能力评价指标,给出了密封结构参数设计方案,密封座涂层材料为Cr_(3)C_(2)-NiCr,涂层弹性模量250 GPa,涂层厚度为0.3 mm,椭圆率为,过盈量为0.02 mm。研究结果可为高温、高压、腐蚀环境下封隔器的开发和应用提供理论指导。

鄂西南岩溶地下河水金属元素污染来源与健康风险评价

鄂西南地下河水是恩施地区工农业生产和人类生活的重要岩溶水源,然而人类活动已明显改变了地下河水金属浓度,地下河水金属污染与健康风险研究变得尤为重要。该文测定鄂西南地区22组岩溶地下河水样品中10种金属元素(Fe、Al、Cu、Pb、Zn、Cr、Ni、Cd、Mn和As)的浓度,应用多元统计分析方法和PMF模型对地下河水金属污染来源进行分析,结合PMF模型利用健康风险评价模型对暴露的人群健康风险进行评价。结果表明,Al在部分地下河水中超标,是引起污染的主要金属元素。Fe、Al、Pb和Mn在绿葱坡地区浓度较高,受酸性污染物和地质背景综合影响,Cu、Ni和Cr主要受地质背景和城镇污水排放双重影响,Zn、Cd和As主要受工农业生产等多种人类活动影响。PMF来源分析表明金属来源有城镇污水排放源、成土母质造成的自然源、酸性污染物和地质背景综合源、农业源和采矿工业源。鄂西南地下河中Cr通过饮用途径暴露的儿童可能致癌风险(6.06×10^(-5)a^(-1))已经超过最大可接受风险值5.0×10^(-5)a^(-1)。城镇污水排放源是成人(31.9%)和儿童(36.8%)非致癌风险的主要污染来源。农业源是成人(52.2%)致癌风险的主要污染来源,城镇污水排放源是儿童(44.5%)致癌风险的主要污染来源。优先控制这些来源是降低研究区健康风险的关键。

“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。

基于频率域电磁法的城市地下金属管线无损探测技术

研究设计了一种地下金属管线电磁探测系统,利用双向同步控制和数字图像处理技术实现对管线位置、深度、种类等信息的探测和分析。通过锁相放大技术提高灵敏度并抑制噪声干扰。实验证明该系统可靠可行,不同位置的金属管具有不同的振幅和相位差,二次场信号随水深增加而减弱。该方法为城市金属管道无损检测提供了新的思路和方法,有望在实际应用中发挥重要作用。

某铜矿通风系统优化

矿山生产中,通风系统扮演着关键角色,直接影响工作面环境的安全性。以银山铜矿为背景,针对-358,-458 m中段的通风系统,通过现场调查和测定,并对测定数据进行统计与分析。结果发现,该铜矿存在-358 m铅锌老系统风机通风效果不明显,-458 m中段采区通风困难,通风构筑物不完善等问题。为此,建立Ventsim三维仿真系统模型,制定通风系统优化方案,完善通风构筑物,并对实施方案优化效果进行模拟。工程实践结果表明,风速合格率为从原来的35.6%提高到73.7%,作业面工作环境得到明显改善。该优化方案有效解决了矿山面临的通风与环境问题,为类似矿山提供了经验。

金属非金属地下矿山存在的安全问题和对策

地下矿山作为重要的矿产资源开采基地,其安全问题一直备受关注。金属和非金属矿山存在的安全问题涉及岩体的稳定性、通风与透水、火灾爆炸等多个方面,对工人的生命财产安全造成威胁。本文将通过深入剖析金属非金属矿山的安全隐患及其影响,分析国内外相关研究成果,提出一系列有效的安全对策。从而提高人们对该行业安全问题的认识,促进矿业行业的可持续发展。

金属地下矿山安全高效采矿方法选择及应用

从现阶段我国金属矿开采过程分析,基本上浅层矿产资源开采殆尽,大部分金属矿山因储存深度大,只能选择地下开采方式,增大开采作业难度,很容易出现安全事故,直接威胁到开采人员的生命安全。基于此背景,在金属矿山开采中,采矿方法选择显得非常重要,是矿山科学合理规划、安全生产的基础保障。从现阶段使用的开采方式而言,很大程度上产生了一些安全问题,并且开采效率不高,受到诸多因素的影响,最终无法保证金属矿产资源的有效供给。本文通过对金属矿山采矿方法现状分析,阐述了金属地下矿山安全高效采矿方法选择,分析了金属地下矿山安全高效采矿方法应用,为金属地下矿山安全高效采矿方法选择和应用提供了参考。

含断层金属矿地压显现规律研究与防控措施

断层是金属矿山采空区稳定性的薄弱环节,也是地压显现治理的难点。以金山店铁矿为背景,基于现场调研结果,借助微震监测与数值模拟相结合的方法,对含断层金属矿山的地压显现规律进行分析。结果表明,在构造应力和自重应力双重作用下,采空区附近断层对空区围岩稳定性有显著影响。断层位于采空区内部时,主要表现为穿过断层巷道的局部破坏,而对上下盘巷道影响较小;断层位于空区上盘时,随着空区面积增大或隔离矿柱宽度减小,会导致断层与空区间的矿柱应力集中区叠加,出现大范围屈服破坏。建议对过断层的巷道局部破坏部位采取二次支护的应对措施;对于断层与空区内的矿柱大范围屈服部位,则应尽量避开在应力集中区布设开拓和采准巷道。该研究结果可为治理含断层矿山地压显现提供参考。