The hard-and-thick strata ACTS both as the floor ofcoalseam No. 7 and as the roofofcoalseam No. 9 in Zhangshuanglou coal Mine; and coal seam No. 9 is also hard.
In the part of west flank of Lujiatuo minefield, the normal siltstone roofofcoalseam 8 changed into coarse to medium-grained sandstone, and also had phenomenon of coal seam pinch-out.
吕家坨井田西翼部分区域八煤层顶板由正常的粉砂岩变为粗中砂岩，并有煤层变薄现象。
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This paper puts forward support plan through analyzing strata behavior regularity ofcoal roadway in seam with soft roof, soft coal and soft floor.