近距离煤层群开采工作面自燃火灾防治技术

石圪台煤矿为浅埋深近距离易自燃煤层群开采,上覆采空区遗煤较多,与周边小窑采空区漏风通道畅通,采空区塌陷分散地表漏风不易控制,存在较大自燃隐患。针对这一开采特征,总结出一套适合近距离煤层群开采的综合防灭火技术体系。采取加快推进速度、预测预报、封堵漏风通道、均压、注浆、注氮等关键技术,有效预防了采空区自然发火,保障了工作面的安全回采。     

麻家梁矿近距离煤层开采工作面漏风规律研究

针对近距离煤层开采过程中采空区漏风通道、漏风规律复杂的难题,以麻家梁矿14201综放工作面为研究对象,详细介绍了近距离煤层开采时采空区漏风影响因素,并通过布置测点对14201工作面漏风规律进行分析研究,监测数据表明,工作面区域通风量随工作面风流的流向逐渐降低,工作面区域漏风量随工作面风流的流向逐渐增加,距离胶带顺槽50~75m的范围为工作面通风量最小,漏风量最大的区域,该区域升温煤层氧化升温速度快、自燃危险性高,是14201工作面在生产期间防灭火的重点区域。     

近距离煤层群开采过程中上覆煤层采空区气体变化规律

近距离煤层群开采过程中邻近层之间产生大量相连通的裂隙,采场情况十分复杂,并伴随不同煤层间因通风引起近距离煤层群漏风,在研究漏风规律过程中,煤矿工程现场煤层群采空区漏风规律与单煤层开采漏风规律有很大区别,开采过程中采空区气体的分布规律也更加复杂,给采空区煤层自燃预测预报带来了困难。通过理论分析、现场监测相结合的方法研究近距离煤层群开采过程中上覆煤层采空区气体变化规律,为制定采空区煤自燃预防措施提供科学依据。     

近距离煤层联合开采自然发火规律研究

针对山西灵石华苑煤业有限公司近距离煤层上、下工作面联合开采引起的采空区自然发火问题,采用能位测定与SF_6示踪技术相结合的方法检测复杂采空区漏风通道、判断漏风方向、估计漏风风速。现场结果表明,该方法有利于提高复杂采空区漏风检测的效率和准确性,避免单一SF_6示踪技术盲目性,对预防近距离煤层采空区煤炭自燃具有实际意义。     

SF6示踪气体在近距离煤层群工作面漏风检测中的应用

近距离煤层群是指在开采本煤层时对邻近煤层有明显采动影响的煤层群。以许疃煤矿7₂28回采工作面为例,上覆存在7₁煤层采空区,在煤层采动影响下形成多种漏风通道,漏风形式复杂,严重影响矿井的安全生产。利用SF6示踪气体连续定量释放法对7₂28工作面及回风巷漏风量规律进行定量研究,在0~150 m（距下隅角距离）范围内工作面主要向采空区漏风,在150 m后采空区向工作面漏风,整体漏风量为93 m³/min,漏风率为4.7%。回风巷在煤层间距薄弱处,存在明显向上覆采空区漏风现象,漏风量为37 m³/min,漏风率为1.9%。通过测试掌握了工作面及巷道漏风规律,针对性地提出预防措施,为该工作面的安全生产提供了保障。     

浅埋藏近距离煤层群开采漏风规律研究

为了防止开采煤层的自燃威胁,并重点防治相邻上覆煤层采空区的自燃。采用SF6示踪气体定性测定漏风的测试方法,通过对神东矿区不同层间距综采工作面进行漏风的观察,研究总结煤层间距不同时的漏风规律,为开采近距离易自燃煤层群时采取相应的漏风控制措施提供依据,尽可能地降低采空区自然发火的可能性,也为今后采空区漏风控制提供科学依据和有效的防范措施。     

浅埋近距离煤层群工作面上隅角贫氧致因及综防技术

我国神东、平朔、大同煤田赋存着大量浅埋近距离煤层群,浅埋近距离煤层群具有煤层埋藏浅、煤层间距近等特点,在开采扰动下,层间易产生裂隙形成漏风通道,当地表空气进入上覆采空区,易引起上覆采空区遗煤自燃,间接影响下层煤开采过程中工作面上隅角的氧气浓度,造成贫氧现象。为了探究浅埋近距离煤层群工作面上隅角贫氧致因,提出防治贫氧的措施,以大恒煤矿91103综采工作面为研究背景,采用理论分析、CDEM数值模拟以及SF6示踪气体漏风测试等方法进行了研究。结果表明:地面裂缝、沉积现象明显;模拟煤岩损伤、破裂过程、裂隙发育,得出地表与上覆采空区、工作面贯通模型;利用连续定量释放SF6示踪气体在工作面进行漏风测定,测定结果验证了数值模拟中地表、上覆采空区以及工作面的贯通。工作面上隅角贫氧是由于浅埋赋存煤体破碎析出的低氧气体、采空区氧化衍生气体以及防灭火注入的惰性气体,在通风负压和大气压力的双重作用下,通过漏风通道进入工作面,加之U型通风方式的通风特点等多种因素共同造成的,其中工作面与地表贯通造成漏风严重是上隅角贫氧的主要致因。基于对贫氧致因的研究,大恒煤矿采用了井上下堵漏、安设风帘、埋管抽采、风机配合风筒等综合性防治措施,有效解决了工作面上隅角贫氧对安全生产的制约和影响,确保了工作面上隅角氧气浓度始终处于正常水平。     

近距离煤层群开采上层采空区气体变化规律

近距离煤层群开采过程中邻近层之间产生大量相连通的裂隙,采场情况十分复杂,并伴随不同煤层间因通风导致的煤层间漏风,致使采空区漏风规律与单层开采有很大区别,采空区气体的分布规律也更加复杂,给采空区煤层自燃预测预报带来了困难。因此通过理论分析并结合现场监测结果研究近距离煤层群开采本层及上层采空区气体变化规律,为制定采空区煤自燃预防措施提供科学依据。     

浅埋深近距离煤层群综采工作面低氧原因分析与防治对策

基于神东矿区厚松散层薄基岩浅埋深近距离煤层群的开采特点,分析了工作面低氧气体的来源及涌出原因,给出了工作面低氧的防治对策。认为:神东矿区煤层处于N_2-CO_2带,加之采空区遗煤低温氧化产生大量低氧气体,在通风负压和大气压力的作用下,通过漏风通道由采空区向回风隅角涌出,造成工作面低氧。低氧的防治是多种技术手段的综合应用,在开拓开采方面,尽量少留或不留联巷,减少采空区遗煤,采空区达5个以上时,相邻工作面留设足够距离的隔离煤柱;在安全监测方面,设置氧气传感器、警示标牌,建立低氧预警机制;在通风系统方面,根据实际条件采用"U+L"型、"Y"型或均压通风系统;在通风技术及管理方面,采取封堵漏风通道,对采空区进行泄压等措施。     

近距离煤层群开采上层采空区气体变化规律

层间距小的煤层,在开采过程中很容易产生大量的裂隙,形成漏风通道,给采空区遗煤自燃的监测预测带来困难。为了能更好地分析层间距小的煤层开采过程中采空区的气体运移规律,该文通过对官地矿28412工作面现场监测并结合理论分析研究近距离煤层群开采过程中采空区气体的运移规律,为预防采空区遗煤自燃给予了相应的理论指导。     

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

正~~     

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