试验表明模拟煤层的部分基本上无破坏，爆破设计应采用欠深预留保护层来保护底部煤层不受抛掷损害作用。
The experiment indicates that the part simulating coal layer was not damaged to some extent, and suggests that less-deep protection layers…
面板底部都安装和上涨到龙骨以及沿中心线煤层。
Both bottom panels fitted and tacked to keel as well as along centreline seam.
石炭系灰岩为薄层灰岩，对煤层开采有影响的灰岩主要是太原统底部单层厚度超过4米的灰岩层。
The Carboniferous limestone system are thin layers of limestone. Those which influence coal extraction are mainly single layers of limestone over 4m thick at the bottom of Taiyuan system.
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