1. Lignitous coal, humic acid, fragments of plant remnants and asphalt are main forms of existing organic substances.
褐煤、腐殖酸、残余植物碎屑和地沥青等是现存有机质的主要类型。
2. Research of Reasonable Top Coal Thickness for Lignitous Coal Deposits in Dayan Mining Area
大雁矿区褐煤层综放开采合理顶煤厚度的研究
3. As a result, reasonable thickness of top coal for 30 # seam, a low metamorphic lignitous coal seam in Dayan mining area, was given.
在大量实验室相似材料模拟试验及现场实践的基础上，探讨了低变质褐煤进行放顶煤开采时顶煤运移的特殊规律，给出了大雁矿区综放开采顶煤的运移规律和合理的分层厚度。