Complexity analysis of blast-induced vibrations in underground mining: A case study

Blasting in geological bodies is an industrial process acting in an environment characterized by high uncertainties (natural joints, faults, voids, abrupt structural changes), which are transposed into the process parameters (e.g. energetic transfer to rock mass, hole deviations, misfires, vibrations, fly-rock, etc.). The approach to this problem searching for the “optimum” result can be ineffective. The geological environment is marked out by too many uncertainties, to have an “optimum” suitable to different applications. Researching for “Robustness” in a blast design gives rise to much more efficiency. Robustness is the capability of the system to behave constantly under varying conditions, without leading to unexpected results. Since the geology varies from site to site, setting a robust method can grant better results in varying environments, lowering the costs and increasing benefits and safety. Complexity Analysis (C.A.) is an innovative approach to systems. C.A. allows analyzing the Complexity of the Blast System and the criticality of each variable (drilling, charging and initiation parameters). The lower is the complexity, the more robust is the system, and the lower is the possibility of unexpected results. The paper presents the results obtained thanks to the C.A. approach in an underground gypsum quarry (Italy), exploited by conventional rooms and pillars method by drilling and blasting. The application of C.A. led to a reliable solution to reduce the charge per delay, hence reducing the impact of ground vibration on the surrounding structures. The analysis of the correlation degree between the variables allowed recognizing empirical laws as well.     

新庄井田高岭石粘土岩中菱铁矿的研究

在永城矿区新庄井田二叠系下石盒子组内含有菱铁矿, 呈分散状、结核状分布在高岭石粘土岩中, 通过系统测试分析, 研究了菱铁矿在高岭石粘土岩层中的含量和特征, 对于高岭石粘土岩和菱铁矿的开发利用具有重要意义     

Long-term economic sensitivity analysis of light duty underground mining vehicles by power source

LHD's are expensive vehicles; therefore, it is important to accurately define the financial consequences associated with the investment of purchasing the mining equipment. This study concentrates on longterm incremental and sensitivity analysis to determine whether it is feasible to incorporate current battery technology into these machines. When revenue was taken into account, decreasing the amount of haulage in battery operated equipment by 5% or 200 kg per h amounts to a $4.0 × 10~4 loss of profit per year. On average it was found that using battery operated equipment generated $9.5 × 10~4 more in income annually, reducing the payback period from seven to two years to pay back the additional $1.0 × 10~5 investment of buying battery powered equipment over cheaper diesel equipment. Due to the estimated 5% increase in capital, it was observed that electric vehicles must possess a lifetime that is a minimum of one year longer than that of diesel equipment.     

矿井水文地质类型划分的Fisher判别分析法——以开滦矿区为例

针对开滦矿区11个生产矿井水文地质类型重新划分问题,根据新出台的《煤矿防治水规定》有关矿井水文地质类型划分的标准要求,采用Fisher判别分析法,选取6项考核指标,建立线性判别函数,进行矿井水文地质类型重新划分.结果表明:11个生产矿井中有1个为极复杂型、5个为复杂型、5个为中等型,Fisher判别分析法划分的矿井水文地质类型与实际划分结果相符;Fisher判别分析过程中遇到了"极复杂型"样本数量太少,仅为1个的情况,造成交叉验证的结果正确率为72.7%,剔除后正确率就提升为100%;Fisher判别分析法对有代表性的样品进行交叉验证的正确率为100%,说明该方法可以科学地判断矿井水文地质类型.     

Water protection in the western semiarid coal mining regions of China: A case study

The coal industry in China has been moving from the semiarid eastern to the drier western regions since the beginning of this century. Water protection is of the utmost concern for coal mining in these regions. Lu’an, as one of the state coal mining bases in China, has been seeing increasingly heavier pressure for the protection of water resources. This article considers Lu’an as an example and describes the ways these concerns may be alleviated. High mine-water utilization rates have effectively reduced wasting of water and, consequently, have reduced water demand. Using the top layers of the Ordavician as aquifuge barriers can prevent floor karst water inrush into the longwall face and can protect the regional Ordovician karst water resources at the same time. The strength of the overlying Quaternary clay can protect against roof collapse and has successfully preserved the Quaternary porous water resource.     

Pushover analysis of underground structures: Method and application

Pushover analysis is common because of its conceptual simplicity and computational attractiveness in computing seismic demand. Considering that traditional pushover analysis is restricted in underground structures due to the stark differences in the seismic response characteristics of surface structures, this paper proposes a pushover analysis method for underground structures and its application in seismic damage assessment. First, three types of force distribution are presented based on ground response analysis. Next, the target displacements and analysis models are established according to force-based and performance-based design. Then, the pushover analysis procedure for underground structures is described. Next, the applicability of pushover analysis to underground structures is verified by comparing the responses of a Chongwenmen subway station determined by the proposed procedure and by nonlinear response history analysis. In addition, two other points are made: that the inverted triangular distribution of effective earthquake acceleration is more practical than the other two distributions, and that performance-based design is more effective than force-based design. Finally, a cyclic reversal loading pattern based on one cycle of reversal loads as an earthquake event is presented and applied to the seismic damage assessment of underground structures. The results show that the proposed pushover analysis can be effectively applied to the seismic design and damage assessment of underground structures.     

Sensing for advancing mining automation capability: A review of underground automation technology development

This paper highlights the role of automation technologies for improving the safety, productivity, and environmental sustainability of underground coal mining processes. This is accomplished by reviewing the impact that the introduction of automation technology has made through the longwall shearer automation research program of Longwall Automation Steering Committee (LASC). This result has been achieved through close integration of sensing, processing, and control technologies into the longwall mining process. Key to the success of the automation solution has been the development of new sensing methods to accurately measure the location of longwall equipment and the spatial configuration of coal seam geology. The relevance of system interoperability and open communications standards for facilitating effective automation is also discussed. Importantly, the insights gained through the longwall automation development process are now leading to new technology transfer activity to benefit other underground mining processes.     

科学计量学视野下的《傲慢与偏见》研究——一个案例性的探究

选择1998—2009年中国学术期刊网收录的关于《傲慢与偏见》研究的458篇论文,尝试运用词频、共词、社会网络分析及信息可视化等科学计量学方法,对国内十多年来《傲慢与偏见》的研究现状、研究主题、研究力量分布、研究水平及整体概况和特征等进行了计量分析和可视化识别,对国内该文学研究领域的各方面状况做了一个比较客观而系统的描绘与判断,发现了一些用其他研究方法难以发现的问题。同时,作为一种新的研究方法的探索性尝试,初步探讨了该方法在文学研究领域使用的可能性和前景,以及应注意的若干问题。     

山丘区地下水资源控制开采的分析与评价

地下水资源储量对某一地区是一定的，亦是有限的。北方地区由于地表水资源本不丰富，地下水资源就更为珍贵。尤其是山丘区其地下水资源因含水层极薄、储量非常有限，若不遵循一套科学的开发利用规划而无序开采，所造成的一系列环境恶化、甚至给人类带来灾难性的报复，将是无法估量的。以黑龙江省鸡西市为例加以阐述。     

开采沉陷预计分析系统研究

介绍了在MapInfo 6.0平台上用MapBasic和Visual C++ 6.0语言进行二次开发设计出的开采沉陷预计分析系统。主要介绍了系统的开发平台、运行环境、系统的结构及其功能,以及开发系统所涉及的关键技术。Visual C++ 6.0中的ODBC技术提供的Access数据库将其与MapInfo 6.0有机结合起来,对开采沉陷预计的相关数据进行操作和分析,从而预计出地表移动变形的范围、程度和趋势等,实现了开采沉陷预计分析的可视化。     

Techno-economic review on storage of petroleum products in abandoned underground salt mines: A case study on underground salt mines of Sardareh region,Garmsar, Iran

During the past few decades, along with creation of new needs, large spaces of underground mines (especially abandoned mines) have found new applications, e.g., storage of petroleum products. Utilization of empty spaces of these mines as hydrocarbons storage facilities decreases the costs of construction of underground spaces, which can be very expensive and costly. On the other hand, crude oil and other hydrocarbons nowadays are one of the most important factors affecting political and a major part of the domestic economy is achieved through them. Thus, in this paper, a feasibility study has been performed on the application of underground salt mines near the city of Garmsar on the southern edge of Alborz mountains and on the north of the central desert of Iran. Through studies of documentaries, field observations and considering technical, geometrical and defensive criterion, the most suitable abandoned underground mine for reutilization as a storage facility is selected and presented.     

低周波装置在煤矿电力系统中的应用分析

本文结合晋城煤业集团公司电力系统 ,分析了电力系统在低周波下运行的危害、防止方法 ,针对安装使用ZPJH装置在晋煤集团电力系统的安全运行中存在的问题 ,提出了解决对策     

住宅小区地下汽车库通风设计

地下汽车库已成为住宅小区的一个重要组成部分。本文介绍了自然通风 机械排风兼排烟系统相结合的地下汽车库通风设计,探讨了通风兼排烟系统在转换过程中各部件的控制方式。     

Determination of volumetric changes at an underground stone mine: a photogrammetry case study

Photogrammetry, as a tool for monitoring underground mine deformation, is an alternative to traditional point measurement devices, and may be capable of accurate measurements in situations where technologies such as laser scanning are unsuited, undesired, or cost-prohibitive. An underground limestone mine in Ohio is used as a test case for monitoring of structurally unstable pillars. Seven pillars were photographed over in a 63 day period, punctuated by four visits. Using photogrammetry, point clouds of the mine geometry were obtained and triangulation surfaces were generated to determine volumes of change over time. Pillar spalling in the range of 0.29–4.03 m³ of rock on individual rib faces was detected. Isolated incidents of rock expansion prior to failure, and the isolated failure of a weak shale band were also observed. Much of the pillars remained unchanged during the monitoring period, which is indicative of proper alignment in the triangulated surfaces. The photographs of some ribs were of either too poor quality or had insufficient overlap, and were not included. However, photogrammetry was successfully applied to multiple ribs in quantifying the pillar geometry change over time.     

Serviceability analysis of deep underground openings driven in jointed-rock

The performance of underground excavations is inevitably influenced by rock mass characteristics, presence of joints and their geometrical properties, depth below surface and state of in-situ stress field. The objective of this paper is to investigate the behaviour of deep underground tunnel opening existed between two bedding planes, Such planes weaken the strength of rock mass and may cause rock slippage/rotation along them. Therefore, the state of stress-displacement, after tunnel opening has been introduced, is examined using two-dimensional elasto-plastic finite-elements code, RS~(2D). The results indicate that, there is significant drop in the normal stress along joints over tunnel opening; slip occurs due to reversal in the direction of shear stress(e.g., inward shear displacement is produced) and there is discontinuity in the strength contours of rock surrounding tunnel after they have been intersected by bedding planes.     

功能符号学视角下的多模态话语分析——以2010年上海世博会会徽为例

近年来,随着多媒体的发展,社会和文化话语意义产生日益复杂化的趋势,语言不再是意义构建的唯一手段,图像、声音和手势等交流模态也不再作为副语言在语言交流中起着辅助作用,而是和语言符号一起形成更为宽泛的符号资源共同参与构建意义。从功能符号学的视角,在克瑞斯和斯文提出的视觉语法基础上,对2010年上海世博会会徽进行了多模态话语分析,向读者揭示了会徽图像的再现意义、互动意义和构图意义。     

浅谈管理案例教学中教师的作用

案例分析已日益成为许多管理类课程教学的必要手段，案例教学的效果与教师的作用密切相关。本从教学前的导向、教学的准备和课堂组织引导以及对学生案例分析成绩评定等三个方面，分析了教师在管理类课程案例教学中的作用。     

A case study of multi-seam coal mine entry stability analysis with strength reduction method

In this paper,the advantage of using numerical models with the strength reduction method(SRM) to evaluate entry stability in complex multiple-seam conditions is demonstrated.A coal mine under variable topography from the Central Appalachian region is used as a case study.At this mine,unexpected roof conditions were encountered during development below previously mined panels.Stress mapping and observation of ground conditions were used to quantify the success of entry support systems in three room-and-pillar panels.Numerical model analyses were initially conducted to estimate the stresses induced by the multiple-seam mining at the locations of the affected entries.The SRM was used to quantify the stability factor of the supported roof of the entries at selected locations.The SRM-calculated stability factors were compared with observations made during the site visits,and the results demonstrate that the SRM adequately identifies the unexpected roof conditions in this complex case.It is concluded that the SRM can be used to effectively evaluate the likely success of roof supports and the stability condition of entries in coal mines.     

基于因子分析的城市职能特征分析——以西部省会城市、直辖市为例

为了对我国西部省会城市和直辖市的城市职能特征及其类型划分有一个初步的认识,根据国家统计局《中国城市统计年鉴》的数据资料,对该地域的城市进行了职能特征分析与分类.以城市的基本经济活动作为确定城市职能的出发点,选取14个指标作为西部10个省会城市和一个直辖市的城市职能分析的原始指标,借助SPSS10.0统计软件,运用因子分析法对14个指标数据进行了分析处理,得到两位公因子.在此基础上计算出西部10个省会城市和一个直辖市的城市职能主因子的综合得分,同时对其城市职能进行了聚类分析,分出三大类两亚类,旨在从整体上把握西部城市的发展趋势.     

我国两化融合的需求分析初探

信息化与工业化融合是国民经济和社会信息化的重点,是我国现阶段改革发展的关键问题。基于"两化融合"的基本概念和发展目标,从发展阶段、地域、行业、产业链等方面分析了"两化融合"的现状和需求,提出了不同发展阶段、不同地域、不同行业"两化融合"发展的对策。