石油焦的燃烧特性处于烟煤和无烟煤之间。
However, with the extension of mining depth, the distribution of soft coal seam has been expanding.然而,随着矿井开采范围的延深,松软煤层的分布范围呈不断扩展趋势。
The II3123 face is a light type caving face of three-soft coal seam. the roof is cracked, sloughing and roof fall often occur.前言: 石台煤矿II3123工作面为“三软”煤层轻放工作面,顶板破碎易掉,片帮、冒顶时常发生。