大采高综采工作面末采阶段来压规律与顶板控制技术

为研究大采高综采面末采阶段矿压显现规律,保证设备快速回撤,以察哈素煤矿3101首采面末采阶段开采实践为工程背景,采用理论分析和现场实测相结合的方法,研究工作面推进速度对来压特征影响,确定合理等压位置并提出末采支护方案。结果表明:工作面加速推进可使来压步距和来压持续长度明显增加;利用停采等压技术可有效控制来压位置;合理留设等压间隔煤柱,可保证挂网和贯通回撤阶段顶板压力显现较缓和;采用补强支护和相关顶板控制技术可保证回撤通道的稳定性。     

浅埋中厚煤层超长工作面末采矿压规律研究

为探究浅埋条件下中厚煤层超长工作面进入末采阶段时的矿压显现规律,以锦界煤矿31114综采工作面为研究对象,通过分析相似工作面矿压数据得出：浅埋中厚煤层地质条件下,工作面周期来压步距与工作面长度近似成反比,来压强度随工作面长度增加而增加,但增幅不大|理论推测31114工作面末采时工作面来压步距为9.58m,最大来压强度约为46.9MPa|末采等压位置为距回撤通道贯通5.4m处。最后采用3DEC软件对工作面贯通进行模拟分析,结果显示：工作面贯通回撤通道时回撤通道顶板下沉量为14.04cm,正帮鼓起2.2cm,工作面支架活柱下缩量为22cm。     

超长大采高综采工作面末采回撤调压关键技术研究

针对超长大采高综采工作面末采阶段的矿压调控问题，采用理论分析、数值模拟和现场试验的方法，通过研究小保当煤矿112201工作面末采贯通阶段的围岩应力分布规律以及矿压显现特征，确定相应的矿压调节技术方案，有效调控末采阶段工作面的周期来压步距，维护了顶板岩层稳定性，实现了工作面柔性塑料网(宽15m×长360m)的顺利铺设。研究表明：工作面末采期间回撤通道的围岩应力将由回采帮向煤柱帮转移，加强回撤通道围岩支护强度，可保证回撤通道稳定性|通过调整工作面回采速度，改变周期来压位置和减小来压持续长度，可实现工作面的顺利挂网与贯通，对类似工作面设备的顺利回撤具有借鉴意义。     

综采工作面末采回撤期间矿压显现规律研究

为了确保综采工作面在末采期间支架顺利回撤,基于东曲煤矿工作面的开采技术条件,通过现场矿压观测和分析,研究了综采工作面采场以及巷道在末采期间的矿压显现规律。研究表明:工作面在末采阶段,工作面来压步距增大,但来压强度仍未超过液压支架的最大承受能力,工作面内液压支架初撑力较小,因此造成煤壁多次出现片帮等现象。工作面在距离回撤巷道约20 m时,回撤巷道围岩变形量突增,但巷道内单体支柱未出现折断现象,因此巷道具有一定稳定性。     

大采高综采工作面矿压显现规律研究

为研究大采高综采工作面的矿压显现规律,以山西某矿3301大采高综采工作面为研究背景,对该工作面的周期来压步距与初次来压步距进行数值模拟和现场实测,结果表明:运用数值模拟和现场实测得出的该工作面的初次来压步距约为45 m,周期来压步距约为23 m,周期来压步距约为初次来压步距的1/2,数值模拟计算结果与现场实测结果一致,数值模拟计算方法可有效应用于大采高综采工作面周期来压步距与初次来压步距的计算中。     

7.0m大采高工作面覆岩破断及矿压显现规律研究

为解决神东矿区7.0 m大采高综采工作面的安全高效开采问题,采用现场实测、理论分析和物理模拟的手段,对19个特大采高工作面的矿压规律和关键技术进行研究。研究结果表明:特大采高工作面矿压显现较普通采高工作面更加强烈;由于特大采高工作面采高明显增大,覆岩第一亚关键层易进入垮落带,难以形成"砌体梁"结构,而呈"悬臂梁"结构周期性破断,形成工作面的周期来压,其持续长度与支架控顶距接近,较关键层"砌体梁"结构来压持续长度明显偏大;并且随着埋深的增大,高位关键层的破断对特大采高工作面矿压显现的影响也逐渐加大,多关键层的同步破断显然会传递更大的覆岩载荷,进而加剧了工作面矿压显现。针对特大采高工作面的矿压显现特征与特殊的覆岩破断规律,建立了支架合理工作阻力的确定方法,研发了特大采高工作面开采设备,开发了大断面巷道支护技术、强制放顶技术和末采快速贯通技术,实现了特大采高工作面的安全高效开采。     

浅埋近距离煤层工作面末采阶段等压原理与应用

为研究浅埋近距离煤层工作面末采阶段等压原理,以高家梁煤矿20314工作面末采阶段为工程背景,首先利用关键层位置判别法确定2-2上煤层间距5 m处的细粒砂岩为亚关键层,间距32 m处的粗粒砂岩为主关键层;通过覆岩岩层离层量Sn判断了上覆岩层破断层位,然后,分析工作面末采阶段不采取停采等压和采取等压技术2种情况下工作面贯通后上覆岩运动规律,并通过理论计算确定工作面距回撤通道6.6 m处为最佳停采等压位置,并在20314工作面末采阶段进行现场试验,回撤工作安全顺利完成。     

综采工作面末采阶段来压规律与顶板控制技术

为分析综采工作面末采阶段矿压的情况,使得设施可以及时回撤,用理论分析和实际相联系的方式,探究工作面进度对来压特点的影响,明确适当等压位置。工作面推进的加快可直接影响来压步距,并且来压的时间长度也显著的增加。使用停采等压技术能够高效的控制来压位置,使用补强支护和顶板控制方式能够确保回撤退道的稳固性。     

综采工作面末采及回撤矿压显现规律与顶板控制技术

神东矿区综采末采使用辅巷多通道回撤技术,通过对末采阶段和支架回撤阶段矿压显现规律的研究,提出了末采等压的顶板控制技术。以补连塔煤矿22303综采工作面为例,研究得出:在综采工作面末采贯通前需通过计算留预留一定尺寸的等压煤柱进行停采让压,当工作面来压后基本顶回转断裂,形成稳定砌体梁结构,在贯通时主回撤通道将不会来压,能够保证支架的安全回撤;当让压后工作面仍不来压,则工作面在回撤时将处于来压状态,需要加强回撤通道的支护强度,防止压架事故发生。     

综采工作面末采及回撤矿压控制技术

某矿综采末采使用辅巷多通道回撤技术,通过研究末采阶段和支架回撤阶段的矿压显现规律,结合矿山实际条件提出了末采等压的顶板控制技术。将此技术应用于某矿综采工作面,研究得出:在综采工作面末采贯通前需通过计算留预留一定尺寸的等压煤柱进行停采让压,以便形成稳定砌体梁结构,在贯通时主回撤通道将不会来压,能够保证支架的安全回撤;当让压后工作面仍不来压,则工作面在回撤时将处于来压状态,为防止压架事故的发生,需要加强回撤通道的支护强度,提高安全系数。     

China rare earth market review

正November 1~10,2014Chinese rare earth market was still inactive.Demand for rare earth products was weak.Consumers took a wait-and-see attitude for lower price.As it was an off season for rare earth products,it was expected that prices of rare earth could continue turbulence at the bottom in short terms.Due to a sharp drop,demand for rare earth from downstream recovered.Affected by new energy vehicles,wind powder and energy-efficient appliances,production of rare earth permanent     

China rare earth market review

正August 1~10,2014 There was some good news in rare earth industry recently.Restructuring plans of rare earth groups led by Baotou IronSteel Group and Xiamen Tungsten Group respectively have been approved by MIIT.And rare earth storage policy,which had been expected for a very long time,has been launched officially.Pushed by the good news,rare earth price started to rebound since August 5.Price of didymium oxide and dysprosium oxide rose about 1% to 2%,averagely.About 10% of     

China rare earth market review

正July 1~10,2014Due to weak demand from downstream industry and slow transactions,rare earth market remained weak and price of rare earth products continued to decline.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,     

New energy vehicle:an opportunity for rare earth magnets

<正>Extracted from Securities Guide 1.Popularity of new energy vehicles—an irresistible market trend1.1 Progress of new energy vehicles Chinese Premier Li Keqiang said recently on a visit to Xi'an BYD Autos that new energy vehicles,especially new energy bus,can lessen environment and noise pollution.He encouraged the use of new     

注浆加固技术在十三矿-685 m进风大巷中的应用

针对煤矿开采深度不断向深部延伸,掘进巷道受深部高应力的影响越来越大,巷道围岩整体稳定性差,矿山压力显现越剧烈现象,一般锚网喷加锚索支护无法从根本上控制巷道的变形。总结了平煤股份十三矿-685 m进风大巷注浆加固技术,依据对巷道掘进之后变形监测数据的采集,对巷道变形机理进行分析研究,并对注浆时段进行了合理选择,在对巷道的注浆工艺进行了充分论证的基础上,对巷道进行了注浆。注浆后效果表明:巷道滞后注浆时间段的选择非常重要,巷道在恰当的时间内进行注浆加固施工,能有效控制巷道的变形,巷道注浆后变形量明显减小,岩体的稳定性明显增强,减少了巷道日常维修工作,降低了矿井的生产成本,保障了矿井的安全生产。     

稀散金属产业的观察与思考

分析了近年来国内外稀散金属产业的生产、应用、资源与市场状况.铟锡氧化物靶材、砷化镓晶片、锗红外材料、铼高温合金和硒在电解锰及玻璃的应用等已成为稀散金属的主要应用领域.稀散金属的产量快速增长达到历史高位而导致了市场的失衡.以GaInP_2/GaAs/Ge,CIGS和CdTe为代表的非硅系太阳能电池是稀散金属的新兴应用领域,将给稀散金属带来日益增长的需求.     

China rare earth market review

正November 21~30,2014Due to weak demand from downstream industries,transactions of rare earth in Chinese domestic market were inactive.It was difficult to sell any rare earth products except for dysprosium oxide and terbium oxide.Suppliers lost confidence in recent market.Demand for rare earth products was soft.Consumers continued to take a wait-and-see attitude.Rare earth export market remained slow.     

Current situation and future trend of China rare earth luminescent materialindustry(continued)

<正>Developing ecological lighting source The world is facing the big problem of energy shortage today and the contradiction between economy development and environmental protection is worsened.Therefore,people are more likely to choose an ecological light source that is more energy efficient and environmental friendly.The choice provides great opportunity for the development of rare earth optical material industry in China.The concept of green lighting positions rare earth luminescent material as a leading player in illumination market.The light source of both rare earth luminescent lamp and LED lamp is ecological and energy saving.This is why     

Galaxy Magnets achieved the net profit of 34.02 million yuan in the first six months of 2014

正Galaxy Magnet announced its financial results for the first half of 2014 on August 14.For the first six months ended on 30 June 2014,Galaxy Magnet achieved operation income of RMB 182.3 million,up8.40% over the same period of 2013,and the net profit attributable to the shareholders of the listed company of 34.02 million yuan,increasing 35.49% over the same period of last year.Stable performance increase was led by development of new customers and application market of magnets.     

Rare Earth Application in Steel in China

<正>China has rich rare earth resources.Output of rare earth and steel in China ranks the top first in the world.However,there is still certain distance between the steel produced in China and developed countries from the point of varieties and quality.China still has to import some types of steel.Improving the quality should be emphasiZed in future development of steel industry in China.Rare earth can be used to upgrade traditional steel