Mating model on production capacity for the system of cutting coal and drawing top-coal in FMMSC

Being a safe and highly-efficient mining method, fully mechanized mining with sublevel caving （FMMSC） was extensively employed in Chinese coal mines with thick seam. In order to make drawing top-coal furthest to parallel work with shearer cutting coal, decrease failure ratio of rear scraper conveyor and increase safe production capacity of equipments, based on production technology, set up the mating model of safe production capacity of equipments for the system of drawing top-coal and shearer cutting coal in coal face with sublevel caving. It is mean capability of drawing top-coal adapted to the capability of shearer cutting coal in a working circle in the coal face that was deduced. The type selection of equipment of rear scraper conveyor can be tackled with this mating model. The model was applied in FMMSC in Yangcun Coal Mine, Yima Coal Group of China. With the mating light-equipments, the coal output in coal face attained 1.05 Mt in 2004. It gained better technical-economic benefit.

Numerical and theoretical investigations of the effect of the gangue-coal density ratio on the drawing mechanism in longwall top-coal caving

Discrete element calculations of the top-coal drawing process for diferent gangue-coal density ratios were conducted to investigate the efect of the gangue-coal density ratio on the drawing mechanism in longwall top-coal caving.The efects were analyzed for the drawing body,the top-coal boundary,and the recovery of top coal.The results show that for increasing density ratio,the initial drawing body on the goaf side is farther away from the drawing support and its width and volume gradually increase.The upper part of the sickle-shaped drawing body extends near the initial drawing body with increasing density ratio in the normal cycling stage,and the distance from the drawing body to the initial drawing body is its maximum width.The larger the density ratio,the smaller the height of the top coal above the goaf at the end of the initial drawing process.The height of the top-coal boundary decreases with increasing density ratio,until it reaches a limit.In a normal cycle,due to hysteretic development,the top-coal boundary moves toward the goaf until the density ratio is approximately 2.0,which is consistent with the physical experiment results.Finally,increasing the advance length of the working face is benefcial for increasing the overall recovery of top coal.

Reliability analysis of the velocity matching of coal cutting and caving in fully mechanized top-coal caving face

The matching relationship between coal cutting and caving in fully mechanized top-coal caving face is analyzed in detail from the angle of reliability. The coupling equation of reliability is established correspondingly, and the mathematical equation of the coefficient of velocity matching of coal cutting and caving is obtained, which meets a certain reliability demand for making the working procedure of coal caving not influence coal cutting of coal-cutter. The results show that the relationship between the coefficient of the velocity matching and the reliability of coal cutting and caving system is linear on the whole when R <0.9. It is pointed out that different numerical value should be selected for different coal face according to different demand for reliability.

近距离特厚煤层综放开采可行性及合理放煤工艺研究

目前针对近距离煤层厚度变化范围较大、煤层厚度超出正常开采高度的工作面的合理放煤工艺参数研究较少。以内蒙古平庄煤业(集团)有限责任公司西露天煤矿011N1^(-1)工作面为研究对象,开展了近距离特厚煤层综放开采可行性及合理放煤工艺研究。首先,通过理论分析计算出近距离特厚煤层上方021N2工作面开采后底板最大破坏深度为3.88 m,小于011N1^(-1)工作面与021N2工作面之间的距离,表明对下煤层011N1^(-1)工作面进行综放开采是可行的。然后,结合理论分析与现场实测,采用模糊数学方法量化了煤体单轴抗压强度、煤层埋深、煤层厚度、煤体裂隙发育程度、顶板级别及煤层夹矸厚度对顶煤冒放性的影响,基于隶属度函数评定011N1^(-1)工作面顶煤冒放性为中等水平。最后,基于PFC 2D离散元颗粒流软件建立了放煤数值模型,分析了不同采放比和放煤方式对顶煤采出率的影响,发现当煤层厚度超过正常开采高度时,将工作面采放比定为1∶4.5可有效适应煤层厚度变化,此时对顶煤采出率的影响较小,且采用三轮放煤工艺可有效提高顶煤采出率。现场放煤效果表明,优化放煤工艺后,随着煤层厚度的增大,增大采放比能够较好地适应地质条件变化,显著提高工作面顶煤采出量。

大截深综放对含硬煤散体顶煤放出率的影响

为研究含硬煤分层顶煤在大截深一采一放和相同步距两采一放的这两种方式下的顶煤放出率,采用PFC2D软件建立数值模型进行研究,得出顶煤中存在硬煤分层时,前者放出率高于后者;相反,放出率相差甚微。各层顶煤放出率的差异是其主要原因,对于硬煤分层和上位顶煤,放出率均是前者高于后者,而对于下位顶煤,放出率相差无几。前者的这种优越性随着硬煤分层厚度和块度的增加而增加,并存在临界值,当硬煤分层厚度小于此值时,其增加缓慢;反之,急剧增加。从散体运动角度分析,前者使得支架尾梁上方散体顶煤的流动性相对增加和采空区侧矸石的流动性相对减弱,这有利于顶煤的放出。

综放开采顶煤放出规律的BBR研究

借助于自主研制的相似模拟实验台和PFC软件,系统研究了综放开采顶煤放出规律,建立了统一研究煤岩分界面、顶煤放出体、顶煤采出率和含矸率四要素的BBR研究体系。分析了煤岩分界面形态以及支架和移架对其影响,提出了可用抛物线拟合煤岩分界面。将放出体分为发育不完整、基本成熟和成熟3个发育阶段,发现了支架掩护梁影响会使放出体前部发育较快,始终超出椭球体范围的现象,指出顶煤放出体是一被支架掩护梁所切割的非椭球体,定义其为切割变异椭球体。为了提高顶煤采出率、降低含矸率,应尽可能地扩大放出体与煤岩分界面的相切范围,通过确定合理放煤工艺与参数,控制煤岩分界面形态来提高顶煤采出率是可行的措施。待放顶煤区域处于由采空区岩石与支架顶梁形成的拱形挤压力链的卸压区内,在放煤口附近顶煤易成拱。

综放面采放系统设备生产能力配套技术研究

采煤机割煤工序是综放工作面的关键工序,影响到综放工作面的产量和效益.当采煤机型号一定时,为了实现放顶煤工序和割煤工序最大限度地平行作业,提高综放面采煤机的开机率和工作面单产,建立了综放面采放系统设备生产能力配套模型,得到与采煤机割煤能力相适应的循环内平均放煤能力,且后部刮板输送机运输能力应大于循环内平均放煤能力.综放面采放系统设备生产能力配套模型在义马杨村煤矿轻型支架综放开采中得到验证,年产量达到1.05 Mt,取得了较好技术经济效益.

机采高度对顶煤冒放性与煤壁片帮的影响

针对特厚煤层大采高综放开采顶煤冒放性与煤壁片帮难题,采用理论分析、数值模拟及技术经济综合对比分析等方法,分析了工作面机采高度对煤炭资源回采率及煤壁片帮的影响。通过建立特厚煤层大采高综放工作面煤壁片帮的压剪力学模型,分析了大采高综放工作面煤壁片帮机理,研究了相同机采高度情况下大采高综放工作面较大采高综采工作面煤壁片帮更加剧烈的原因。增加液压支架对顶煤的主动支护作用力及选择合理的液压支架架型结构参数,既可以提高顶煤的冒放性,同时还可以降低煤壁的片帮概率。综合分析不同机采高度对煤炭资源回采率、煤壁片帮控制及工程与设备投资的影响,确定罐子沟煤矿大采高综放工作面机采高度为4.5 m,设计研发的ZFY12000/26/47型两柱掩护式整体顶梁大采高综放液压支架使用效果较好。

成庄矿4312工作面对接切眼的研究及运用

通过对成庄矿4312工作面对接切眼的研究和利用,掌握了对接切眼设计,分析了施工过程中存在的问题及解决办法,在其他工作面的再次利用过程中可以把握设计和施工要点,保证工程更优、施工更简便、对接安装回收时间更短,安全生产得到更好的保障。

特厚煤层大采高综放设备的研发

介绍世界首套特厚煤层(<20 m)、大采高(3.5～5 m)综放设备的研制过程、遇到的技术问题和解决方法。

煤层智能开采技术探索分析

煤层开采技术的高效、高质、安全长期以来一直是矿井生产不断追求的目标,而随着现代化技术的不断进步,将电子监测、远程控制、实时通信、智能分析等技术应用到矿井开采中,实现煤层开采的智能化已成为现实。从采煤机记忆截割技术、跟机拉架技术、智能放煤技术、远程干预技术多方面对煤层智能开采技术进行了探索分析,希望能够为其他矿井生产智能化的实现提供参考与借鉴。