极近距离煤层刀柱采空区下走向长壁开采的探讨

通过对 4 0 4 1工作面顶板压力观测及老顶岩梁运动的分析 ,对在极近距离煤层刀柱采空区下进行长壁回采的工作面支承压力显现和顶板活动规律进行了探讨 ,总结了刀柱采空区下长壁工作面的开采经验。     

回采工作面上隅角瓦斯超限的预防与处理

回采工作面由于采空区存在大量的瓦斯,采空区的空气压力要大于回采面的压力,二者存在压力差,在这种压力差的作用下,采空区瓦斯就会涌入到回采工作面,加之上隅角通风不畅甚至根本没风的特点,容易在这个部位形成瓦斯集聚,形成超限。本文通过分析瓦斯集聚的原因,针对性地提出了预防和治理回采工作面上隅角瓦斯集聚、超限的措施,有一定的适用性。     

斜拉锚索支护技术在沿空掘进巷道中的应用

随着陈四楼矿开采产能的逐年加大,采掘接替日趋紧张,需要提前沿空掘巷,形成回采系统。沿空掘进的巷道既受采空区压力又会受到回采工作面动压的影响,巷道的稳定较为困难,尤其是靠近采空区一侧煤柱变形非常严重。针对这一问题,提出了斜拉锚索支护技术,即在轨道巷煤柱侧巷帮内向顶板安装40°仰角、长6.5 m锚索,向底板安装30°俯角、长3.0 m锚索,采用该方案后轨道巷支护效果良好,实现了安全回采。     

采空区上方急倾斜薄煤层开采技术

新集三矿深挖矿井资源,对采空区上方薄煤层进行回采。由于受采空区拉动影响,开采煤层、顶、底板破碎,工作面温度高,架下易窜矸等,通过掘进、回采和通风管理等一系列综合技术措施的实施,实现了安全回采,为采空区上方急倾斜薄煤层开采找出了一条非常重要的出路。     

近距离采空区下煤层开采矿压显现特征研究

以湘桥煤矿10~#煤层开采为工程背景,对上覆采空区的底板破坏情况以及下伏煤层开采的顶板变形进行了理论分析,采用UDEC数值模拟软件对比分析了单一煤层开采与近距离采空区下煤层开采的矿压显现规律。结果表明:相较于单一煤层开采,近距离采空区下煤层开采支承压力应力集中程度更高,其超前支承压力强度更大;同时,由于近距离采空区下煤层开采属于重复采动,下煤层顶板岩层破坏较单一煤层开采更为严重,采场支护强度设计必须考虑上部采空区的影响。因此,在进行近距离采空区下煤层开采时必须采取加强下伏煤层开采超前支护、提高采场液压支架支护强度等措施,以保证近距离采空区下煤层开采顶板的有效管理和安全回采。     

大采深厚煤层复杂条件下冲击地压防治技术

就济宁三号煤矿163下 00工作面沿采空区回采、沿"梯形煤柱"开采、向大断层推进、面向采空区开采等复杂条件下冲击地压危险性进行分析,根据不同务件采取针对性防治技术措施,实现了工作面的安全回采.     

近距离煤层群采空区漏风控制技术

色连二矿主采2号煤层属于近距离煤层群开采,22上和22中煤层间距为0~12 m,这就导致工作面22上煤层会全部进入采空区形成大量浮煤,在采空区漏风供氧条件下极易发生自燃隐患。故研究出"两巷端头封堵"技术来防治采空区漏风,通过对端头封堵间距、采空区三带分布和注氮口位置的优化,确立了一套针对性强的采空区漏风防控的综合措施,有效降低了采空区漏风供氧,进而确保了22中煤层的安全回采。     

某铁矿矿柱回采安全性研究

某铁矿二采区一中段采用空场采矿法进行采矿,经过多年开采该中段未处理采空区体积已经达到40万m3,遗留矿柱矿量超过26万t,为了充分回收矿产资源矿山计划回采矿柱。由于现场未处理的采空区体积较大,而矿柱又是维持采空区稳定性的关键要素,可能部分矿柱的回采或破坏就会诱发一定规模的地压活动,威胁矿山的正常安全生产。所以在矿柱回采之前,对回采区域的矿柱进行安全性研究,可以指导矿柱回采的实施,进而保障矿柱的正常安全回采。结合矿山的现场实际情况,以应力增量理论为基础,采用工程地质调查、室内试验结合数值模拟的方法,对矿山二采区一中段需回采矿柱的安全性进行研究,确定了各回采矿柱的安全系数大小。研究结果表明矿山二采区一中段的矿柱处于安全状态,可以进行部分矿柱回收。     

基于Surfer的采空区积水位置和范围预测研究

一直以来,对厚煤层分层开采及多煤层开采条件下,综采工作面采空区积水位置和范围的圈定,没有合理有效的解决办法。基于Surfer引入“采空区底板三维地形图”这一概念,提出了一种新的采空区积水位置和范围的预测方法,以陕北榆神矿区某矿井为例,工作面期间每推进30～50 m,沿工作面倾向每间隔6台液压支架,利用全站仪观测一次工作面底板坐标和高程数据,依次循环直至工作面回采完成,然后将整个回采工作面底板高程和坐标数据导入Sufer中,生成Grd三维地图网格文件,利用网格文件建立回采工作面“采空区底板三维地形图”模型,通过在低洼和凹陷区插入多个水平面,并调整水平的高程,模拟出采空区积水的位置和范围,直观地反映出综采工作面回采完成后,采空区内部地形起伏变化规律和采空区积水的空间位置,给厚煤层分层开采和多煤层开采时,上覆采空区积水的准确判定提供重要技术支撑。     

顶部富水复杂环境采空区综合处置技术研究

某铁矿山于1980年开始投产,采用竖井开拓,采矿方法为空场法,截至目前形成了诸多采空区,其中上部一矿体回采结束后未及时处理,并且采空区已积水,而下部三矿体正处于回采阶段,其回采过程以及所留采空区可能对上部采空区造成扰动,具有导致上部采空区积水涌至现有回采范围的危险。为保障下部三矿体安全回采,消除上部采空区积水对下部矿体回采过程的安全威胁,采用现场调查、理论分析、定量与定性分析相结合的方式,综合分析了采空区自稳性、后续安全回采范围、综合处置技术方案等。研究表明：下部三矿体回采范围内的8个独立采空区暂时处于相对稳定状态,但长时间暴露会有顶板冒落的危险,其中KQ1#和KQ8#采空区影响波及上部一矿体采空区积水范围,其余6个采空区未波及上部采空区范围,通过技术分析,确定对KQ5#、KQ6#、KQ8#采空区进行充填处理,对KQ1#、KQ2#、KQ3#、KQ4#、KQ7#采空区进行封闭处理,能够保证上部采空区安全和下部三矿体后续回采工作安全,消除矿山开采安全隐患。     

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     

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     

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     

唐口煤矿深部复杂开采工作面瓦斯分源涌出规律研究

研究工作面瓦斯涌出规律对工作面瓦斯治理有重要意义。为了得到唐口煤矿深部3号煤层复杂开采条件下工作面回采时期瓦斯涌出时空演化规律,选取6304工作面作为对象,采用实测方法研究6304工作面瓦斯涌出规律。结果表明:6304工作面瓦斯涌出量为6.534 m³/min,其中煤壁占34.27%,落煤占29.62%,采空区占36.11%;沿工作面倾向由低到高,瓦斯浓度整体为上升趋势,其中1—76号架工作面瓦斯浓度小于0.20%,76—102号架瓦斯浓度上升明显,最大为0.387%;上隅角的后部采空区是工作面的瓦斯主要涌出源,上隅角1号测点瓦斯浓度0.78%,上隅角周边3号、5号、7号、8号、9号测点瓦斯浓度平均为0.643%;周期来压时,上隅角瓦斯相对平时较高。研究为针对性的瓦斯分源监控与灾害防治提供基础。