The occurrence is steady and the structure is simple with FM, JM types of coal, whose roof is limestone and siltstone and bottom is muddy siltstone and sandy mudstone;

赋存稳定，结构简单，煤种为FM、JM，煤层顶板为石灰岩、粉砂岩，底板为泥质粉砂岩、砂质泥岩；

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The stability of main and immediate roof structure and its influence on strata behaviour are analysed. The failure features of roof coal between top and bottom slice are thoroughly studied.

深入分析了层间顶煤的破碎特点，指出层间顶煤的破碎效果是多因素综合作用的结果，而在不同的开采条件下将具有不同的放顶煤效果。

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