前和煤业东胶带运输大巷钻孔卸压围岩控制技术

为有效解决前和煤业3#煤层东胶带大巷在原有锚网索支护下围岩变形量大的问题,结合巷道变形特征,确定采用钻孔卸压技术,采用理论分析和数值模拟的方式确定卸压钻孔在修巷作业前,垂直于巷帮打设,钻孔深度为8 m,结合巷道的具体条件确定巷道采用卸压钻孔+让压支护的围岩控制方案,并采用矿压监测验证支护效果。结果表明:支护方案实施后,顶底板和两帮的最大移近量分别为141 mm和132 mm,有效解决了巷道两帮及底板鼓起量大的问题,保证了巷道围岩的稳定性。     

采空区下回采巷道支护方案数值模拟研究

为了确定采空区下巷道合理的支护方案,以某煤矿为研究对象,采用FLAC数值模拟软件,通过对不同监测断面的围岩应力进行监测,对采空区下回采巷道的围岩应力进行了数值分析。研究表明,巷道采用锚杆和工字钢棚联合支护比单一支护效果更好,能够明显降低顶底板位移量,因此,确定了基本支护方案为锚网+工字钢棚复合支护形式。     

采空区下巷道锚杆支护参数优化数值模拟分析

为研究采空区下布置巷道围岩的控制技术,以厚煤层采空区下布置的2311工作面巷道支护参数选择为背景,采用数值模拟技术,利用正交试验,建立了27组锚杆支护巷道围岩力学模型,分析了不同支护参数与巷道围岩变形之间的关系,确定了最优巷道锚杆支护参数方案。结果表明:基于极差分析,影响巷道顶底板变形的最大因素包括帮与顶锚杆间距、帮与顶锚杆排距,其中帮锚杆长度、帮锚杆间距、间排距等三个因素对巷道两帮的变形影响最大;基于灰色模糊理论,确定锚杆间排距0. 7 m、锚杆直径18 mm、顶锚杆长2. 6 m和帮锚杆长2. 4 m为最优支护参数方案。模拟结果为现场巷道围岩控制提供了理论基础。     

煤矿深井高应力巷道支护技术应用

同煤集团某矿井属于深井开采,井巷常处于高地应力软岩环境,传统的棚式支护、低预应力低强度锚杆支护以及被动支护方式已经不能满足支护需求,需合理确定主动型联合支护方式。以某深井高应力巷道支护为研究对象,在研究地应力状态、围岩强度、岩石成分的前提下,通过数值模拟方式确定井巷最佳支护方案,选择高预应力高强度高刚度锚杆锚索联合的方式控制深部井巷围岩的稳定性。进行全面的顶底板、两帮的位移监测后发现,该支护方案下巷道整体变形量减少,两帮移近变形呈稳定状态的时间提前,明显改善了巷道顶底板变形状况,起到良好的支护效果。     

动压影响下软弱泥岩顶底板巷道支护技术研究

动压影响下软弱泥岩顶底板巷道存在围岩变形量严重问题,制约矿井正常生产。本文在对巷道原支护参数进行详细分析基础上,认为在动压影响下的泥岩顶、底板巷道未对底板进行加固从而引起底鼓量过大是造成巷道围岩变形量过大主要原因。提出采用以锚注技术为核心的巷道支护优化方案,并具体对巷道支护参数及施工工艺进行阐述。现场应用表明,优化后的巷道支护措施有效对巷道围岩进行控制,底板底鼓量控制在10mm以内,确保了巷道使用安全。研究结果可以为类似情况下的其他矿井巷道围岩控制提供一定借鉴。     

高水平构造应力巷道围岩稳定性数值模拟分析及控制

为了解决高水平构造应力条件下巷道围岩易失稳的难题,采用数值模拟的研究方法,分析了两种支护形势下巷道围岩响应特征,提出了巷道底板采用锚索束注浆加固的治理方案,并结合数值模拟进行现场工业性试验。结果表明:巷道围岩原支护方式对巷道的顶板及两帮起到较好支护效果,但巷道底鼓量较大;在进行底板锚索束注浆加固支护后,顶底板累计移近量为142mm,两帮的移近量为123mm,较原支护围岩断面整体收缩减小48%左右,底板锚索束整体补强作用显著,能够有效控制巷道底鼓增大趋势,保证了巷道围岩的完整性和稳定性。     

综采工作面小煤柱留巷巷道支护技术研究及应用

以斜沟矿16502工作面为工程背景,针对该煤层为复合顶板,而以往巷道支护设计不科学、增加支护困难和后期维修频率的问题,根据小煤柱沿空掘巷的围岩控制原理,结合6#煤层顶底板条件,选定巷道支护设计方案。并经围岩强度测试和数值模拟小煤柱留巷围岩应力分布情况,试验表明,基于高预应力强力支护原理的巷道支护方案,有效控制巷道顶底板围岩变形。     

基于压力拱理论破碎围岩巷道结构失稳研究

针对破碎围岩巷道结构失稳问题,基于压力拱理论综合分析巷道顶底板、两帮围岩结构失稳机制;采用FLAC~(3D)数值计算模拟软件剖析巷道围岩结构失稳机理和灾变特征,通过工程现场检测分析巷道支护效果。结果表明:底-帮和顶-帮结合部是支护关键区,该区域能够有效阻碍覆岩顶、底板和两帮围岩运移,缓解岩体灾变概率;支护后巷道沉降量较未支护状态下巷道沉降量平均降低50%,应力峰值减小且呈线性分布,动力灾害得到有效控制,巷道实现安全掘进。     

基于离散元方法的深部巷道层状围岩稳定特性研究

采用块体离散元方法UDEC,通过细观参数校核及无支护状态的宏观物理-数值模型对比,建立了深部层状围岩巷道模型,分析了4种支护方式对深部巷道层状围岩体承载特性及变形破坏特征的影响。在块体离散元巷道模型基础上,为进一步研究深部矩形巷道层状围岩体承载能力,通过监测模型内部的应力、塑性区分布及顶底板和两帮位移,对不同支护方式的压力拱成拱特性进行了分析。研究结果表明：不同支护方式下深部巷道顶底板及两帮围岩均出现了应力集中区,采用锚杆+锚索+喷射混凝土+工字钢支护后巷道表面收敛程度及围岩的位移均最小,支护效果最明显,对围岩的控制效果最好。研究结果可为实际工程中的矩形巷道层状围岩稳定性控制提供参考。     

采动影响下沿空巷道围岩稳定性分析与控制技术研究

为解决采动影响下16305工作面回风巷变形量大的问题,通过数值模拟的方法分析巷道围岩的稳定性,并根据模拟结果与现场矿压显现情况提出巷道的支护方案。结果表明:动压影响下沿空巷道左侧的塑性区发育范围大于巷道右侧,底板岩层存在着一定的拉应力破坏区域。支护方案实施后,顶底板移近量为200mm,两帮移近量为150mm,巷道围岩变形得到有效控制。     

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     

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     

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     

2014 second batch of rare earth quota released

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矿用防爆轴流对旋主要通风机叶片ANSYS模态分析及应用

高效节能矿用防爆对旋主要通风机的叶片是主要通风机运行的关键部件,叶片在运行时不断受到气流的作用力,从而使叶片产生振动,当叶片振动的频率与叶片的固有频率接近时,容易产生共振从而导致叶片的断裂。一旦叶片断裂时,对主要通风机的安全运行产生致命的影响,从而导致矿山、化工等企业发生重大事故,将会产生不可估量的损失。基于有限元分析软件ANSYS,对高效节能矿用防爆轴流对旋主要通风机叶片进行模态分析及产生对应的六阶模态频率,对主要通风机叶片的运行频率、固有频率及产生的共振问题进行了原理分析,并且解决了叶片频率共振的问题,从而为主要通风机叶片结构设计提供理论依据,并对主要通风机叶片的安全运行提供保障。     

2013 NdFeB export analysis

<正>China totally exported nearly 24,000 tonsof NdFeB products during 201 3,including 18,825 tons of permanent magnet,valued USD 1.34 billion at an average price of 71.4 USD/kg;3,277 tons of NdFeB magnetic powder,valued USD 1 01 million at an average price of 30.9 USD/kg;1,334 tons of strip casting ribbon,with total export value of USD 74million at an average price of 55.3 USD/kg;and 586