In coal-seam roof, distributary channel sedimentations mostly are vertical accretion, and the continuity of sand body evolvement is well.
顶板分流河道沉积作用以垂向加积作用为主，岩体演化具有较好的继承性；
This paper introduces the producing and technology characteristics of the square and rectangular double-welded seam pipe. And designing of the pass parameters of the cold-bent channel steel.
介绍了双焊缝方矩形钢管生产技术的特点及冷弯等边槽钢孔型设计参数。
And then studied the area channel flowed along and destructiveness to the coal seam, provide a reference for the mining of coal seam 8 in mi…
并对古河流的流经区域和煤层的破坏程度作了研究，为井田中深部八煤层的开采提供了参考依据。
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