Based on the analysis of gas source at the working face with "three-soft" unsteady coal seam, the authors introduce the principle and method of gas suction by roof-rock drilling.

前言： 通过对“三软”不稳定煤层采煤工作面瓦斯来源的分析，介绍了采用顶板岩石钻孔抽放解决瓦斯问题的原理和方法。

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This paper analyzed the influence of mining depth, coal seam dip, mining height and face length on depth of floor water-conductive fissure zone.

综合分析了开采深度、煤层倾角、煤层开采厚度、工作面斜长等地质采矿条件对底板采动导水破坏带深度的影响。

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Combining with the actual situation in coal face, expound the key technology for large inclined Angle thin seam face so as to assure that slided coal can't come in goaf.

结合某矿采煤工作面实际情况，阐述了大倾角薄煤层工作面的关键技术处理措施，保证了煤下滑不窜入采空区。

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But they face a similar decision on a Headingley strip that traditionally favours seam.

BBC: England recall Caddick