Moreover, there are some other influencing factors such as: thick loose bed, surface mining degree, impel speed of working face, coal mining and roof manage methods, mining procedure and time.
Methods to define the laneways loose zone of thick coal seam with enriched gas and spontaneous combustion is studied in the article and define the rational the length of sealed borehole.
研究了铜川矿务局下石节煤矿高瓦斯油气共生易自燃厚煤层巷道松动圈的范围，确定合理封孔长度。
3
To increase lump coal ratio in stopes, a scheme is put forward for coal falling by loose pre-shearing millisecond blasting, and hole arrangement parameters and blasting parameters are adjusted.