浅埋深厚煤层覆岩运动规律研究

为了深入了解浅埋深厚煤层开采的覆岩运动规律,采用现场实测等手段对阳湾沟煤矿6204工作面覆岩运动规律进行了详细的研究,结果表明:阳湾沟煤矿导水裂隙带高度为97m,为采厚的12. 12倍,垮落带高度为22m,为采厚的2. 75倍;采空区的中间测点下沉量大于周边的下沉量,中间下沉速度较快,在整体的形式上表达出对称方式;阳湾沟煤矿在较窄工作面地表的启动距为78m,大约为埋深的0. 45倍左右,启动距偏大;工作面上方不能形成"竖三带",而只能形成冒落带和裂隙带的"两带"结构形式。     

浅埋深综放开采下地表沉陷实测规律研究

为揭示浅埋综放开采条件下地表沉陷规律和为工业广场建(构)筑物附近工作面安全开采提供依据,在阳湾沟煤矿6204工作面上方设置地表移动观测站进行观测研究。结果表明:浅埋综放开采条件下地表沉陷规律总体符合一般沉陷规律,但地表移动变形主要集中在采空区上方,且伴随永久裂缝;工作面推进过程中,地表移动和变形总体上是连续渐变的,但在地表下沉某个过程存在突变现象,下沉增加很快;地表移动活跃期下沉量集中,占全部下沉量的94%。     

厚黄土下综放高强度开采地表沉陷与覆岩破坏实测

为研究厚黄土下厚煤层综放开采地表沉陷和覆岩破坏规律,通过在工作面地表建立岩移观测站和地面钻孔水文勘探,进行了地表沉陷变形实测和覆岩破坏高度钻探测定。总结研究地表岩移观测站实测资料和覆岩破坏探测钻孔水文观测资料,得出厚黄土综放高强度条件下地表沉陷剧烈,曲线较陡,在下沉盆地边缘沉陷变形曲线收敛较慢,最大下沉速度偏大,采动影响范围偏远;覆岩破坏探测结果显示综放覆岩破坏异常发育,导水裂缝带高度与综放采厚近似成正比,裂高采厚比例系数平均为19.75。研究成果为黄土区综放地表开采损害防治和水体下采煤及顶板水害防治提供技术支撑。     

浅埋深薄基岩综放覆岩运移规律的埋深效应研究

采用相似模拟实验的方法,研究了浅埋深薄基岩条件下综放开采覆岩运移规律的埋深效应,结果表明:浅埋深薄基岩条件下,虽然埋深不同,综放采场覆岩均形成了稳定的"悬臂梁+铰接岩梁+拱"结构,松散层和地表会随着"铰接岩梁"周期性失稳而滞后工作面成整体切落式垮落,地面出现台阶式下沉,工作面与地表沟通,进而直接破坏覆岩含水层和地表水系,生态环境遭受严重的破坏;随着埋深的增加,地表最大下沉值增加,最大下沉量位置距工作面的距离增大。     

王坡煤矿综放开采地表移动与覆岩破坏规律研究

以王坡煤矿为实验矿井,通过地表移动观测、钻探和钻孔电视探测等手段,对王坡煤矿3202综放工作面地表移动规律和覆岩破坏规律进行研究,揭示了该矿综放条件下地表移动变形规律和覆岩破坏规律。研究成果为今后指导该矿及其他类似条件矿区三下采煤提供了依据和经验。     

昌汉沟煤矿浅埋深煤层开采地表移动变形规律研究

针对浅埋煤层的矿压显现规律不同于普通埋深煤层的矿压显现规律的情况,运用地表变形观测与理论分析,研究了昌汉沟煤矿浅埋深煤层开采地表移动变形规律,结果表明工作面覆岩不存在"三带",基本上为垮落带和裂隙带所构成的"两带",浅埋煤层的顶板基岩沿全厚切落,基岩破断角较大,破断直接波及地表.     

综放工作面导水裂隙带高度分布式光纤监测技术

为了确定荫营煤矿150313综放工作面导水裂隙带发育高度,本文采用数值模拟和现场实测方法对覆岩变形特征进行研究。数值模拟结果表明,150313工作面垮落带高度为26 m,垮采比为3.59;裂隙带发育高度为85.8 m,裂采比11.87。工作面导水裂隙带高度井下观测试验共布置3个分布式光纤监测钻孔,采用BOTDR技术对工作面回采过程中覆岩变形特征进行测试。监测结果表明：分布式光纤监测技术可准确监测覆岩变形与移动特征,测试覆岩“两带”的高度。传感光缆光损耗较大的点或者断点所处的层位对应于工作面垮落带高度,起裂临界应变位置对应于工作面裂隙带高度。根据现场测试结果可知,150313综放工作面覆岩垮落带高度为28.51 m,垮采比为3.94;导水裂隙带的高度为75.44 m,裂采比10.43。研究成果可为类似条件矿井顶板水害防治和水资源保护提供参考。     

浅埋深特厚煤层综放开采覆岩破坏规律研究

浅埋深特厚煤层综放开采有可能使采动裂隙导通地表,对地面及井下作业构成威胁。通过综放开采覆岩破坏高度的理论计算和计算机数值模拟,以国投哈密一矿7#煤层为典型案例,对浅埋深特厚煤层综放开采覆岩的移动破坏规律进行研究,为相似条件下特厚煤层综放开采的安全实施提供借鉴。     

厚煤层综放开采覆岩移动规律数值模拟分析

为了掌握高河矿综放工作面上覆岩层移动规律,为工作面布置及“三下”开采提供参考,结合高河矿E1302综放工作面地质情况,采用数值模拟方法,对工作面地表移动、上覆岩层移动及岩层破坏特征进行模拟分析。研究表明:岩层移动在基岩内衰减较为明显,在松散层内近似整体沉降,厚基岩具有一定的控制地表沉陷变形的能力;导水裂缝带发育髙度最大约为140 m,裂高采厚比为20;综放开采强度大,地表的沉陷变形值增大,地表裂缝增加,从而导致地表下沉系数增大。     

高瓦斯综放开采覆岩导气裂隙带高度演化规律研究

为探究高瓦斯厚煤层综放开采覆岩裂隙带高度演化规 律,以主焦煤矿2303综放工作面为研究背景,通过正交试验 研究了采厚、硬岩比例系数、煤层倾角、采深等因素对综放面 导气裂隙带发育高度的影响特征,总结了各因素与导气裂隙 带高度之间的关联性。通过 UDEC 软件模拟了综放面“两 带”覆岩运移特征,模拟结果为:工作面充分采动时垮落带高 度为21.7m,裂隙带高度为45.0m,台阶下沉现象明显。采 用钻孔窥视仪对2303工作面“两带”进行探测,对比采动前 后的覆岩裂隙情况可得:垮落带高度为20.7m,裂隙带高度 为44.3m,与数值模拟结果一致。     

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