间距对上保护层开采保护效果影响的相似模拟实验研究

为研究上保护层开采保护效果随层间距的变化规律,以南桐矿区作为实验背景,保持保护层倾向工作面开挖长度、煤层埋深、倾角、岩层物理力学性质相同,将层间多层岩层处理为复合岩层,分别进行近距离、远距离和超远距离上保护层开采相似模拟实验。综合分析被保护层卸压规律及基于被保护层垂直于层面的膨胀变形保护准则所得保护范围可知:上保护层开采被保护层卸压曲线呈“凸形”,且“凸形”中心线偏向下山方向。随层间距增加,“凸形”底部被保护层小于原岩应力的卸压范围与“凸形”顶部卸压曲线顶部较大卸压的范围均呈减小趋势;两者中心位置均向下山方向转移,且后者转移度大于前者;被保护层卸压曲线中卸压范围的卸压程度及应力集中范围的应力集中程度均呈减弱趋势;以垂直层面的膨胀变形量3‰确定的上下边界膨胀变形保护角均小于《防治煤与瓦斯突出规定》中相应条件的卸压角,因此以该方法确定的保护范围相对《防治煤与瓦斯突出规定》偏于安全,且随层间距增加保护范围长度呈加速减小趋势。     

我国干旱半干旱煤矿区环境问题及对策

近年来,伴随着东部地区煤炭资源的枯竭,我国煤炭开采的重心逐步由东部湿润地区转移到西部干旱半干旱地区。生态环境脆弱是干旱半干旱区自然本底特征,大规模的煤炭开采一定程度上改变了当地的环境现状,带来了诸多环境问题。基于"井工"和"露天"两种不同煤炭开采方式,文章分析了干旱半干旱区煤炭开采造成的主要环境问题,并基于生态累积效应理论,分析了采煤活动的生态累积评估方法。最后,针对存在的主要环境问题提出了相应的对策与策略。     

生物炭负载氧化石墨烯对离子型稀土矿区土壤中重金属的阻控效应

以脐橙皮渣和天然石墨为原料,采用改进Hummer-共热解法制备了生物炭负载氧化石墨烯(BGO)材料,利用土壤钝化实验考察了 BGO复合材料对稀土矿区土壤重金属形态的影响,土柱淋溶实验探讨了淋滤液重金属含量变化特征以及土壤重金属垂向迁移规律,确定了淋溶条件下重金属的累积释放模型.结果表明,添加BGO复合材料提高了土壤pH...     

Safety Management in Coal Mines—Risk Assessment

The present state of accident hazard at work in the Polish mining industry is presented. A comparison is made of the accident indices in relation to other countries. A reference is made to the work safety management system implemented in the mines. Safety management is discussed in terms of risk management. On the basis of the natural death index and that of accidents at work, numerical scales are presented defining the limits of the inadmissable, tolerable, and acceptable risk. The course of variation of risk indices for fatal, serious, and minor accidents is evaluated. The results of the assessment for all kinds of accidents at work in the mining industry are presented.     

Role of behavioural factors in green supply chain management implementation in Indian mining industries

Green supply chain management (GSCM) integrates ecological concepts with those of supply chain management in order to minimize energy and material usage and to reduce adverse impacts of supply chain activities on the environment. GSCM implementation in mining industries depends largely upon certain factors which are influenced by human behaviours. Human behaviour is dynamic in nature and the relationships between them continuously evolve and change. In this ever-changing context, therefore, identifying and ranking the behavioural factors that affect GSCM implementation becomes essential. This can be taken as a reference by the decision makers while deciding the hierarchy of action necessary for effective implementation of green practices in mining supply chains. The present research attempts to explore various behavioural factors affecting GCSM practices and their interactions which help to attain green-enabled needs. Interpretive structural modelling (ISM) is employed in this research to extract the interrelationships among the identified behavioural factors.     

The influence of geomorphology on the role of women at artisanal and small‐scale mine sites

The geologic and geomorphic expressions of a mineral deposit determine its location, size, and accessibility, characteristics which in turn greatly influence the success of artisans mining the deposit. Despite this critical information, which can be garnered through studying the surficial physical expression of a deposit, the geologic and geomorphic sciences have been largely overlooked in artisanal mining‐related research. This study demonstrates that a correlation exists between the roles of female miners at artisanal diamond and gold mining sites in western and central Africa and the physical expression of the deposits. Typically, women perform ore processing and ancillary roles at mine sites. On occasion, however, women participate in the extraction process itself. Women were found to participate in the extraction of ore only when a deposit had a thin overburden layer, thus rendering the mineralized ore more accessible. When deposits required a significant degree of manual labour to access the ore due to thick overburden layers, women were typically relegated to other roles. The identification of this link encourages the establishment of an alternative research avenue in which the physical and social sciences merge to better inform policymakers, so that the most appropriate artisanal mining assistance programs can be developed and implemented.     

Investing in fertilizer–mining companies in times of food scarcity

The primary goal of the paper is to show the validity of investing capital in fertilizer–mining companies, both from a market return perspective for individual or institutional investors, or from a hedging standpoint for insurance companies and other economic actors exposed to inflation risk and high agricultural commodity prices. After providing some elements on the fertilizer market and describing the joint dynamics of corn, wheat and fertilizer prices over the last decade, we analyze an exhaustive sample of listed fertilizer producing companies over the years January 2004–December 2012. We show that their shares generated quite good returns over the whole period and extremely high ones during the years January 2004–December 2007, both in absolute terms and compared to their betas. We also exhibit that these returns display higher sensitivities to major agricultural indexes than to the World Bank Fertilizer Index, making the hedging argument quite compelling.     

基于k-SC聚类的飞行操作模式及危险性分析

为挖掘飞行数据中的高危险性操作模式,采用k-SC时间序列聚类算法,并基于K-W检验分析聚类结果与不安全事件之间的关系。以特定条件下某机队着陆阶段的驾驶杆操作数据和长着陆事件为例进行模型验证。结果表明:机队有5类不同的驾驶杆操作模式;不同操作模式的着陆平飘距离分布具有显著性差异,且长着陆的危险性最高可达68.18%。研究结果可为提升航空公司飞行员操作能力、分析飞行员操作特性及其他不安全事件（如重着陆、擦机尾等）提供理论参考。     

江苏省矿业循环经济

论述了矿业循环经济的定义和内涵、矿业循环经济与传统矿业经济的区别、矿业循环经济中的原则及技术载体,分析了江苏省发展矿业循环经济的有利条件,指出了矿业循环经济的重点技术,构建了生态示范区建设的指标体系及给出了重点建设的矿业循环经济生态示范区,简述了江苏省发展矿业循环经济的成就,提出了发展矿业循环经济的措施及建议。     

神木煤矿区土壤重金属污染特征研究

通过对神府煤田开采区3个煤矿区周围土壤Cu、Cd、Cr、Mn、Ni质量分数进行测定及分析,评价了煤田开采对周围土壤的污染程度。结果表明,长期的煤炭资源开发、运输等活动,已导致周围土壤受到重金属不同程度的累积性污染,土壤中Cd、Ni质量分数高于陕西省土壤背景值,且Cd污染程度较高,Ni污染程度较低,而Cu、Cr、Mn基本不受污染。3个煤矿表层土壤各重金属元素质量分数均表现出污染区大于对照区,但这种变化幅度存在一定差异;Cu、Cr、Mn 3种重金属元素虽没有超出背景值,但已表现出一定程度的累积;煤矿周围土壤重金属污染受到开采年限、土壤质地、风向等因素的影响。3个煤矿污染区土壤剖面样品中,5种重金属元素质量分数基本上随着土壤深度的增加呈现降低的趋势,且这种趋势具有波动性。