Aimed at top corner gas management at the low gas blasting face, by upper goaf drainage with decompression in self coal seam, the experience is tried, the effect is obvious.
针对低瓦斯炮采工作面上隅角瓦斯治理，利用本层上采空区泄压释放，进行尝试实验，效果明显。
2
According to the different product structure, butt fusion welding process and lap seam welding process are used to respectively weld left and right half shell of upper body.
上体左、右半壳直焊缝视产品结构不同，分别采用对接熔化焊和搭接缝焊工艺。
3
In solving the problem of deformation in surrounding rocks of the overlying coal entry caused by upper protective seam mining, reinforcing the surrounding rocks by grouting is a feasible method.