The feasibility of the protective coal pillar mining in the artificial inclined steep drift in the thick (ultra thick) coal seam of a large slope is discussed.
论证了急倾斜厚(特厚)煤层伪斜上山保护煤柱回收的可行性。
2
Deficient floor slope Angle of an ore body often needs to dig a drift (or access) in its footwall rock when adopting non-pillar sublevel caving following-vein excavation.