松软厚煤层综放工作面顶煤运移规律研究

为了掌握义安矿松软厚煤层综放工作面顶煤运移规律,运用深基点位移法对22011工作面进行现场实测。结果表明:顶煤始动点随煤层位的不同而变化,顶煤层位越高始动点位置越超前,顶煤运移始动点发生在煤壁前方15~20m位置;顶煤从始动点至煤壁位移量远大于煤壁至顶煤冒落的距离;工作面顶煤运移煤壁前以水平运移为主,工作面煤壁后方以垂直运移为主。研究结果为确定合理的放煤工艺参数,提高顶煤回收率提供参考。     

大倾角松软厚煤层综放面顶煤运移规律实测研究

为了研究大倾角松软厚煤层综放条件下顶煤破坏运移规律,应用深基点位移计进行了现场实测,由观测结果分析得出：顶煤始动点随顶煤层位的不同而不同,顶煤层位越高始动点位置越超前,顶煤始动点超前工作面距离最远为34.23 m;顶煤从始动点至煤壁上方位移量平均为65 mm,占总位移量的32.34%,从煤壁至支架后方冒落前位移量平均为136 mm,占总位移量的67.66%,总位移量平均为201 mm;工作面煤壁前以水平运移为主,工作面煤壁后方以垂直运移为主,顶煤垮落角约为105°;研究结果为分析判断顶煤的冒放性、合理确定放煤工艺参数,提高顶煤回收率提供了依据.     

底分层综放开采顶煤运移规律研究

针对杨村煤矿走向长壁底分层放顶煤开采具体地质条件,利用深基观测孔系统地观测了距煤层底板不同高度的煤层,以及顶板垮落岩层的位移与工作面煤壁距离之间的关系,得出了综放面顶煤始动点位置,以及煤壁前后方顶煤运移规律.将顶煤沿工作面推进方向依次划分为原岩应力区、弹性区、塑性区和散体区4个变形分区,实测了得到了各个分区范围,其中在塑性区内顶煤处于顶煤体的应力一应变全程曲线的峰后区,项煤体属于损伤变形体.     

综放面矿压显现及顶煤运移规律

采用ZYDC-Ⅲ型综采支架工作阻力连续记录仪和KGE30型深孔位移计对湖西煤矿首采综放面支架载荷和顶煤运移进行了实测.实测结果表明:工作面初次来压步距为41.9 m左右,周期来压步距约为15.8 m,工作面来压呈现中间压力大、两端压力小的特征,支架的平均工作阻力为额定工作阻力的66.9%,支架工作阻力发挥较好.顶煤始动点在煤壁前方平均45 m左右,层位越高始动点与煤壁相距越远.顶煤的运移速率随者工作面的推进逐渐加快,在基点距工作面8 m范围内表现明显.上位顶煤位移量大于下位顶煤,且与工作面距离越近,上下层位位移量之差越大,在加速移动区这一差别明显增加.观测期间顶煤位移量最大为65 mm,最小为18 mm,总位移量为38 mm,顶煤冒放性较好.观测结果可为其他工作面和类似条件综放开采提供参考.     

大采高综放开采特厚顶煤运移特征实测研究

为掌握大采高综放开采特厚顶煤的运移特征,采用深基点观测方法,在大同塔山8105大采高综放工作面设置观测站,对特厚顶煤不同层位的运移特征进行观测分析。结果表明特厚顶煤上、下位的顶煤运移具有不同步性,主要分为3个阶段:煤壁前方4.27 m为超前支承压力影响阶段,上位顶煤位移增量大于下位顶煤;煤壁前方0~4 m为顶板回转下沉影响阶段,下位顶煤的位移增量大于上位顶煤;煤壁后方一6~0 m为支架反复支撑一顶板回转影响阶段,下位顶煤的位移增量急剧增加。     

特厚煤层综放工作面顶煤变形力学分析及试验研究

根据斜沟煤矿23103大采高综放工作面特厚煤层赋存条件,运用力学分析、PFC数值模拟和1∶40的大比例物理模拟试验,研究了大采高综放工作面顶煤的变形规律。结果表明:①随着顶煤厚度的增加,支承压力的峰值强度降低,峰值点距煤壁距离增加,支承压力影响范围加大;②顶煤在支承压力峰值区主要为剪切破坏;邻近工作面的煤壁,支承压力降低,顶煤的破坏主要为拉伸破坏;③煤壁前方顶煤运移以水平方向的变形为主;控顶距上方顶煤运移以垂直位移为主;④顶煤是以受拉破坏为主造成冒落;采高4 m时,顶煤垮落角平均值为67.36°,顶板断裂期间,顶煤垮落角的平均值为76.54°。给出顶煤滞后垮落的处理措施,对斜沟及具有相似赋存条件的煤层,具有一定的指导意义。     

较薄厚煤层综放开采顶煤岩运移破坏特征研究

采用FLAC3D数值模拟对较薄厚煤层综放开采顶煤岩力学特征进行了系统分析,得出了顶煤岩运移、破坏及应力分布规律.研究结果表明,综放面上部顶煤位移量明显大于工作面中下部,顶煤的"始动点"在工作面煤壁前方,工作面上位顶煤岩的始动位置超前于下位,垂直位移量随着与工作面距离的减小而逐步增加;在综放面前方,顶煤和上覆岩层在垂直方向始终处于压缩状态.而在工作面上方,顶煤开始出现离层现象;工作面支架所受载主要是顶煤和基本顶变形运动产生的变形压力,沿用中厚煤层综采工作面支架设计已不适用综放面.     

王家岭煤矿12309工作面顶煤破碎特征及运移规律研究

为掌握12309工作面顶煤破碎特征及运移规律,采用理论分析+现场观测分析进行顶煤破碎特征的分析,根据顶煤破坏规律分析得出顶煤受力特征,基于现场测试得出顶煤破碎块度及冒落特征;通过数值模拟进行顶煤运移规律的分析,并在工作面回采期间进行顶煤活动规律的监测。结果表明,顶煤冒落块度基本在40 cm×30 cm×30 cm内,顶煤一般在支架顶梁后方及时垮落;顶煤放出7次后即进入稳定周期,顶煤的运移主要出现在超前工作面10～30 m内,工作面走向上顶煤运移可划分为4个区域。     

放顶煤开采顶煤运移特征及数学模型的建立

基于各矿山放顶煤工作面顶煤运移的实测资料,运用数学方法及计算机技术对放顶煤工作面地质条件各主要影响因素与顶煤运移规律进行研究分析,给出了放顶煤工作面顶煤运移的基本运移规律及顶煤运移规律与工作面主要影响因素之间关系的一般数学模型。     

全息采空区与顶煤运移的时空演化规律研究

放顶煤开采是为解决特厚煤层高产与高效开采的新型方法,是我国特厚煤层开采的发展方向,但特厚 煤层综放开采顶煤堵塞放煤通道的技术难题影响了煤炭的回收率。 本项目结合塔山煤矿 3-5#煤层的实际赋存条件, 采用三维洞穴激光扫描仪和运用现场实测以及数值模拟等科学方法对其顶煤运移规律及采空区顶垮落形态等进行 了系统的研究。 研究结果表明:工作面在推进过程中,顶煤位移量发生变化,且工作面到达一定位置后,位移量变化明 显;当处于顶煤体破坏的过程中,采空区方向的水平位移量与速度增长速率增加;顶煤和顶板运移量呈现 2 种截然不 同的运移特征,前者壁前高于壁后,而后者为壁后高于壁前。     

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