基于“采-充-留”技术的岩层控制效果和机理研究

为进一步研究"采-充-留"协调开采对岩层破坏的控制作用,以开滦某矿中厚倾斜煤层9煤和12煤为研究对象,基于相似材料模型试验,针对协调式跳采全采技术和"采-充-留"协调开采技术对地表的移动变形和覆岩控制效果和机理进行了研究。结果表明,9煤采用协调式跳采全采技术开采,地表下沉系数为0.64。在9煤开采的基础上,采用"采-充-留"协调式开采技术回采12煤,地表下沉系数仅为0.16。全采后岩层裂缝带法向发育高度是采厚的32.1倍,而"采-充-留"协调开采后岩层裂缝带法向高度是采厚的6.3倍,说明了充填体与煤柱形成的联合支撑体能够有效地抑制上覆岩层的垮落,阻隔了两侧采空区的联通,对上覆岩层移动起到良好的控制作用,达到了减小地表移动变形和岩层破坏的目的。     

“采-充-留”协调开采技术原理与应用

我国岩层移动控制主要采用条带开采、充填开采和协调开采方法。针对条带开采采出率较低、全采全充成本较高的问题,提出了一种"采-充-留"相结合的部分开采、部分充填、部分煤柱的协调开采方法,给出了留设煤柱、充填开采工作面、垮落法开采工作面的布置方式和采充留尺寸确定原则,分析了由充填体与小煤柱所构建的联合支撑体的作用原理和形成非充分开采的岩层移动控制实质。通过模型试验验证了该方法对地表下沉的良好控制作用,揭示了其控制覆岩及地表移动的机理。采用"采-充-留"协调开采技术,对某矿村庄下采煤试验区进行了方案设计,地表移动变形预测表明,该技术具有良好的减沉效果,建(构)筑物的损害等级可得到有效控制。该技术为提高滞压资源采出率、降低充填成本、减缓地表损害,提供了新的手段。     

唐山矿“充-留”协调开采覆岩及煤柱变形规律研究

以唐山矿城镇下采煤为研究背景,基于矿井开采条件和生产实践,提出了"充-留"协调开采,采用数值模拟方法揭示了在不同充填率和采留比条件下覆岩和煤柱变化规律,模拟结果表明:研究区采用"充-留"协调开采技术,充填率不小于80%时,工作面顶板完整性较好,煤壁应力峰值降低,充填体阻止应力集中位置内移,能够满足地表房屋损害不超过Ⅰ级的控制要求;煤柱留宽不小于90m时,满足安全核区率85%的标准,煤柱垂直应力峰值较小,发生破坏的可能性较小。现场实施效果表明,该采区充填率80%、煤柱留宽90m时,支架压力分布平衡,村庄影响程度轻微,应用效果良好。     

不同采-留-充开采方法下地表沉陷控制研究

基于浅埋煤层开采下的地表沉陷控制理论及控制方法,提出不同开采方法相结合的开采模式。以关键层理论为依据,试验研究为基础,并结合数值模拟分析,研究了不同采-留-充相结合的开采方法对该矿区地表沉陷的控制作用。结果表明:在充填材料中加入膨胀剂能提高充填体的接顶率;采用采-留结合的方式开采时,采25 m留25 m时地表变形最小,煤柱能够保持长期稳定性;采用采-留-充开采时,若完全置换留设煤柱,即置换25 m煤柱时,充填高度需达到4.5 m,此时充填高度等于采厚,可有效控制地表变形;若置换20 m煤柱时,充填高度只需达到4.3 m,此时充填体最终抗压强度为7.41 MPa,能够维持充填体的长期稳定。     

“采-充-留”协调开采地表移动预测方法

为了提高"采-充-留"协调开采地表移动预测的精度,通过多元非线性回归分析,建立了"采-充-留"协调开采地表最大下沉值与垮落法充分采动条件下地表最大下沉值之比与留宽、采宽及充填宽度之间的函数关系,并对关系式进行可靠性验证。由数值模拟结果回归分析,得到了"采-充-留"协调开采与全部垮落法开采概率积分法参数间的关系式,为"采-充-留"协调开采影响预计和方案设计提供了参考。     

条带充填开采沉陷影响因素分析

针对条带开采采出率较低、全采全充成本较高的问题,提出了一种条带开采与充填开采相结合的网状带式充填开采方法.以某矿工作面地质条件为工程背景,确定合理的工艺参数后进行了数值模拟分析.研究结果表明,在采区内煤炭资源实现全采的条件下,地表变形量也小于建筑物Ⅰ级损坏等级指标,并给出合理的采留宽及临界采留宽;且通过数值模拟分析,得...     

固体充填条带开采采宽与留宽优化设计

针对南屯煤矿采用全采全充模式的固体充填开采无法控制地表沉陷的问题,分析了矿区采用固体充填条带开采的必要性,推导了充填体作用下的煤柱屈服区宽度力学计算公式,提出了顾及煤柱稳定性的留宽设计方法,并推导了采出率与地表变形的数学表达式|采用数值模拟研究了煤柱应力集中系数的变化规律,为力学模型的参数选取提供了支持。结合理论分析和数值模拟的研究成果,对固体充填条带开采的采留宽进行优化设计。研究结果表明：当矿区固体充填条带开采的采宽为53m、留宽为25m时,可较好地控制地表变形、保证煤柱的稳定性和提高资源的采出率。     

短壁跳采胶结充填围岩运动规律研究

针对我国"三下"压煤量大,开采成本高、工序复杂等问题,以某矿建筑物下压覆9~#煤层为工程背景,提出短壁跳采胶结充填开采方法,并对煤柱和充填体协同作用机理及围岩运动规律进行了研究。主要结论如下:工作面支巷设计宽度为5 m,长度为90 m,全厚开采;步骤一采留比1∶3,顶板变形最大14.1 mm,呈波浪形分布,底鼓不明显;步骤二采留比1∶1,顶板位移量最大30.9 mm,底鼓量2.3 mm;步骤三全采全充,顶板位移呈凹陷形分布,最大位移109.1 mm,底鼓最大10.3 mm;开采过程中煤柱应力呈阶梯状分布,呈波浪形向深部转移,充填体应力阶梯状跳跃增大;短壁全采全充后上覆岩层以弯曲下沉为主,直接顶没有发生明显的冒落;底板破坏呈现W-波浪型,矿压破坏带为0~2.2 m,煤柱两侧塑性区1.0 m。     

煤层开采后覆岩导水裂隙带高度的模拟研究

某矿为安全开采煤炭资源,采用经验公式预计和计算机数值模拟方法,按规划设计开采煤层厚度分别研究了单独开采16#煤、17#煤后覆岩导水裂隙带高度,采用经验公式计算为36.1m和29.7 m;采用计算机模拟方法计算为37.1 m、26.9m。研究了按规划设计开采煤层厚度将16#煤、17#煤全采后覆岩导水裂隙带高度为41.7 m。     

工作面不同回采条件的划分及开采危险性预测

在回采上限提高区域内普遍存在薄基岩工作面,在承压含水层条件下开采时,会发生压架突水事故。7340工作面布置在7_2、7_3煤层的复合区域,面临下覆8_2煤层和上覆7_2煤层共计12个工作面已采条件下的重复开采问题,使得该工作面在开采过程中受到多种复杂顶板条件的影响。以7340开采为研究背景,把7340工作面不同回采条件划分为5种情况,包括下覆8_2煤层已采条件下上覆7_2煤层综放遗留浮煤的复采、下覆8_2煤层已采条件下上覆7_2煤层采空区下的夹空开采(夹在上、下煤层采空区间的工作面开采形式)、下覆8_2煤层已采条件下上覆7_2煤层遗留煤柱下开采、断层保护煤柱的开采、7_3煤层采后的采空区复采,并对这5种条件做了危险性评价。     

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。