Front horizontal seam not leveled.
前幅水平缝骨不对称。
Relationship curves between seam dip Angle, horizontal section height and roof deformation are derived, at the seam time, the criterion of failure is given in this paper.
得出了煤层倾角、水平分段高度对顶板变形的影响关系曲线，同时，给出了顶板破断的判据。
The horizontal section top coal caving in steep seam is different from the gently inclined seam.
急斜煤层水平分段放顶煤开采与缓斜煤层不同，工作面沿煤层厚度的水平线布置，长度短。
Point out that the horizontal structure stress is one of the important influence factors on the coal seam floor's failure.
提出水平构造应力是煤层底板变形破坏不可忽略的重要因素之一。
As one of radial horizontal drilling techniques, high pressure water jet drilling technology is capable of using mechanical or water jet apparatus to make a cavity at the selected coal seam.
高压水射流径向水平孔钻进技术是水平孔施工技术之一，它是在垂直瓦斯抽放或煤层气勘探钻孔布置机械或水力扩孔装置，对准选定的煤层部位进行扩孔。
Making use of horizontal pinnate branch well to develop and utilize coal seam gas, is a new drilling technique, which is different from horizontal drilling and has its own uniqueness.
利用水平羽状分支井来开发利用煤层气，是一项新的钻探技术，它有别水平钻井，有其独特性。
It is used when mineral deposits are under a shallow, easily removed overburden, and when the vain of ore or seam of coal runs more or less horizontal to the surface.
它适用于矿床埋藏较浅，覆盖层容易剥离，矿脉(煤层)走向与地表大致平行的矿床。
A construction of the water dam chamber for isolation between horizontal and up and down seam in a mining district is one of the comment water prevention and control methods.
建造防水闸门硐室，进行水平、区上下组煤隔离，是预防水患普遍采用的方法。
A construction of the water dam chamber for isolation between horizontal and up and down seam in a mining district is one of the comment water prevention and control methods.
建造防水闸门硐室，进行水平、区上下组煤隔离，是预防水患普遍采用的方法。
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