极破碎中厚矿体开采方法及稳定性分析

根据极破碎中厚矿体开采中下向进路承载层受力特点, 将其简化为受均布载荷及自重应力的简支“梁”模型, 求出承载层最大拉应力σ_tmax的表达式, 并以最大拉应力强度理论作为承载层的破坏判据, 由此得出下向进路不同承载层厚度与安全系数的关系曲线。当进度高度为3.4 m, 进路宽度为3.0 m时, 安全系数法分析表明人工假顶厚度1.4 m为最优。利用二维有限元分析矿山原有的1.0 m厚人工假顶与安全系数法得出的1.4 m厚人工假顶进路的稳定性, 结果表明下向进路回采时, 影响进路稳定性的主要因素是充填体的力学特性, 顶板沉降位移统计表明, 采用1.4 m厚人工假顶的进路顶板稳定, 与安全系数法分析结果一致。     

某铜矿分段空场嗣后胶结充填人工假顶厚度计算及分析

某铜矿采用分段空场嗣后充填法进行回采,开采过程中留有大量矿石在顶柱中成为永久损失。为安全有效地回收遗留在顶柱中的高品位矿石,需在上中段底部铺设人工假底作为下中段的人工假顶。由于人工假顶厚度是影响巷道稳定性的重要因素,因此本文针对该铜矿的2640m中段建立了钢筋混凝土人工假顶力学模型并进行受力分析。在此基础上利用塌落拱原理与组合梁理论分别计算了人工假顶的厚度,并得出该矿的人工假顶厚度为1.5m。该方法可为同类矿山借鉴。     

某铜矿分段空场嗣后胶结充填法人工假顶厚度计算及分析

某铜矿采用分段空场嗣后充填法进行回采,开采过程中在顶柱中留有大量矿石,成为永久损失。为安全有效地回收遗留在顶柱中的高品位矿石,需在上中段底部铺设人工假底作为下中段的人工假顶。由于人工假顶厚度是影响巷道稳定性的重要因素,因此本文针对该铜矿的2 640m中段建立了钢筋混凝土人工假顶力学模型并进行受力分析。在此基础上利用塌落拱原理与组合梁理论分别计算了人工假顶的厚度,并得出该矿的人工假顶厚度为1.5m。该方法可为同类矿山借鉴。     

下向进路充填采矿法人工假顶强度及配筋参数研究

构筑人工假顶是下向进路充填安全高效采矿的关键和前提,人工假顶充填体强度与配筋参数相互关联,直接决定着回采作业的安全性与经济性。通过建立顶板多层充填体普氏平衡拱模型,优化下向进路充填假顶所受荷载的计算方法;应用薄板理论及弹性力学理论并结合下向进路充填采矿工艺,解析充填体假顶强度要求;将钢筋混凝土结构设计方法应用于下向进路充填假顶配筋率计算,形成下向充填采矿人工假顶强度及配筋率的整体方案。以某金银矿山大结构参数（5 m×5 m）回采进路为例,提出假顶厚2 m,充填体强度不小于5 MPa,Φ12 mm钢筋（HRB335）网度300 mm×300 mm,配筋率0.106%的技术要求,对合理构筑人工假顶和安全高效应用下向进路充填采矿法具有指导意义。     

下向进路充填采矿法人工假顶优化研究与应用

下向进路回采过程中，人工假顶的稳固性是保证下向进路采场安全的重要因素。通过对三山岛金矿下向进路采场人工假顶受力情况进行分析，结合薄板理论，计算出人工假顶厚度与抗压强度函数曲线并得出人工假顶合适的厚度与强度，即人工假顶厚度为0.8 m,强度不小于1.5 MPa,并结合现场实际应用并利用FLAC3D数值模拟软件对下向进路采场回采前后人工假顶应力场、位移场及塑性区分布规律进行分析。结果表明，0.8 m厚的人工假顶在下向进路采场回采过程中能保持稳固性，保证下部采场的安全性，研究结果可为矿山下向进路人工假顶设计和施工提供理论依据。     

近海矿体开采人工假底厚度优化及工程应用

三山岛金矿为了保证矿山近海矿体开采的稳定性和资源的回收率,设计在-165 m中段施工人工假底。通过建立力学模型,应用弹性力学理论对人工假底的失稳机理进行分析,然后应用数值模拟方法对不同厚度的人工假底下开采进路的稳定性进行分析。通过计算分析不同厚度人工假底下开采进路顶板的应力、位移变化特征,得出不同厚度人工假底的稳定情况。结果表明：厚度为0.4 m和0.5 m的人工假底拉应力超出其抗拉强度的分布区域在进路宽度方向上分别占80%和26.7%,最大拉应力分布在假底中部,假底的垂直位移呈不均匀沉降,且假底厚度越小,不均性越大; 厚度为0.6 m的人工假底拉应力均未超出假底抗拉强度,且位移沉降均匀,整体稳定性较好,但施工成本较高。因此,建议人工假底厚度为0.5 m。将优化结果应用于工程实践,结果表明该参数安全经济合理。     

基于厚板理论下向进路充填假顶强度模型及应用

充填假顶作为下向进路式采场的直接顶板,其稳定是该法成功应用的关键,以充填假顶所需强度为研究对象,通过分析下向进路式采矿法典型工艺特征,确定了假顶危险力学状态,并将其简化为四边简支的厚板模型,借助厚板理论符拉索夫基本解答,分析了充填假顶拉应力分布状态,据此建立了下向进路充填假顶强度模型。通过实测大屯锡矿下向进路式采场充填体上覆压力,以最大监测结果0.35 MPa作为基础计算参数,分析确定了假顶底部极限拉应力为0.23 MPa,为保障假顶稳定,考虑1.5的安全系数,设计假顶抗拉强度0.345 MPa。采用FLAC 3D构建了3-1矿体下向进路式采场物理模型,并模拟分析了充填假顶在设计强度参数条件下服务矿体回采过程中应力分布及稳定性状态,矿体回采至最后一分层,假顶拉应力分布于0.10～0.23 MPa,最大值为0.23 MPa,与理论分析结果一致,假顶服务至分层回采结束,未出现塑性破坏。根据模型计算结果与数值模拟分析结果,推荐满足强度指标的最优配比为废石∶尾砂=8∶2,水泥添加量210 kg/m³,质量分数85%,并指导完成大屯锡矿3-1矿体下向进路式采场11万m     

基于可靠度理论的下向进路胶结充填技术经济分析

采用弹性力学中梁理论的分析方法,建立了下向进路充填体的力学模型,求出了下向进路承载层的应力分布规律及最危险点的位置,确定了下向进路胶结充填采矿法充填体稳定性评判依据.在此基础上,将可靠度理论引入下向进路胶结充填采矿法充填体的相关研究,提出了基于可靠度理论的下向进路胶结充填技术经济分析方法,并结合某矿山实际情况,建立了该矿山下向进路胶结充填采矿法承载层稳定性可靠概率为90%时,不同进路宽度条件下承载层厚度与充填成本之间的关系方程.研究表明加大承载层的厚度、减少承载层中的灰砂比,既可保证承载层的稳定性,又可以降低充填成本.对不同进路宽度时承载层厚度与充填成本之间的关系对比分析表明,当该矿山进路宽度增加到5.5 m或6.0 m时,承载层稳定性可靠度达到90%时充填成本将增加3.5%或7.7%,采场的生产能力将提高10%或20%左右.该项研究对安全、高效、低成本的矿石回采具有较为重要的理论意义和现实意义.     

进路法回采顶柱人工假顶的稳定性分析

针对用进路法回采顶柱的人工假顶暴露形状为矩形的矿山地下结构，应用薄板理论和能量原理对其稳定性进行分析。通过建立进路结构力学模型，得出院 假顶变形阶段的挠曲，应力与假顶的强度，受力及工程尺寸等参数的关系式，并具体应用于新城金矿的顶柱回采实践中，结果表明：运用该理论方法分析采场稳定性在生产实际中具有很好的指导作用。     

充填体下阶段水平矿柱回采顶板安全厚度及进路充填采矿法

为了安全回采松散矿碴及低强度充填体压覆下的阶段水平矿柱,采用古典杨森散体压力理论及矩形等厚薄板力学模型分析了留设顶板受载情况及安全厚度,并通过工程实例进行了验证。结果表明,当上中段破碎底部结构不予回采,下中段顶柱留设安全厚度时,可通过进路式充填采矿法实现水平矿柱的安全开采;其中,下中段顶柱高5 m,采高3.5 m,顶板安全厚度1.5 m,矿石回收率68%,贫化率3%,取得了较好的安全与经济效益平衡。     

Market and recycling of NiMH battery

<正>Market status and future trend of NiMH battery1.Global market of small NiMH battery Global market size of small NiMH batteries declined year on year since 2011.The trend will continue to 2018,at the rate of 5%to 10%annually.Demand for small NiMH batteries will be stable gradually.Many electrical apparatuses are powered by the built-in lithium battery today,which is the main reason for the shrunk market of small NiMH batteries.But,for some products,small NiMH     

China rare earth market review

正September 1-10,2014 Affected by the National Day holiday,rare earth transaction was stagnant and the market showed a weak steady state.As there was no good news for downstream market,some products with flat demand would likely rally slightly for some time to     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

2014 second batch of rare earth quota released

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Annual Report analysis of Chinese rare earth-related listed companies in 2013

<正>Chinese rare earth-related listed companies have published their 2013 annual reports.It can be understood from their reports that production and operation activities of Chinese rare earth-related companies were still heavily affected by macro economy and industrial policies.They basically followed the steps of national economy.In 2013,world economy recovered slowly but the economy     

Market opportunities and challenges for rare earth polishing powder

正1.Status of rare earth polishing powder Rare earth polishing powder with high content of cerium oxide began to replace iron oxide for glass polishing and became one of the key materials in glass polishing process since 1940.Compared with traditional iron oxide,rare earth polishing powder has many advantages,such as fast polishing rate,high polishing quality and long service life.It can achieve good surface quality and improve operation conditions.For example,in lens polishing,the polishing work that cerium     

Baotou Research Institute of Rare Earths developed a new RE alloy preparation technology

正Pyrometallurgy Laboratory of Baotou Research Institute of Rare Earths had independently developed a new preparation technology of rare earth alloy for NdFeB.The alloy can remarkably enhance the coercivity of NdFeB magnet but also evidently reduce the production cost of the magnet.The new master alloy was prepared in the kA pilot-scale electrolytic cell by the independent technology.The rare earth master alloy can be used as the raw material for NdFeB.Compared     

China rare earth market review

正November 21~30,2014Due to weak demand from downstream industries,transactions of rare earth in Chinese domestic market were inactive.It was difficult to sell any rare earth products except for dysprosium oxide and terbium oxide.Suppliers lost confidence in recent market.Demand for rare earth products was soft.Consumers continued to take a wait-and-see attitude.Rare earth export market remained slow.     

Galaxy Magnets achieved the net profit of 34.02 million yuan in the first six months of 2014

正Galaxy Magnet announced its financial results for the first half of 2014 on August 14.For the first six months ended on 30 June 2014,Galaxy Magnet achieved operation income of RMB 182.3 million,up8.40% over the same period of 2013,and the net profit attributable to the shareholders of the listed company of 34.02 million yuan,increasing 35.49% over the same period of last year.Stable performance increase was led by development of new customers and application market of magnets.