THICK COAL SEAM LARGE SEAM HEIGHT GOB-SIDE RETAINED PASSAGEWAY METHOD

摘要

A thick coal seam large seam height gob-side retained passageway method, suitable for mine passageway support engineering. The method comprises the following steps: upon mining an upper section coal mining workface (1), constructing, along an edge of a gob (3), a support wall (11) adjacent to a passageway and a pressure buffer wall (13) respectively having therein a ventilation pipe (10); maintaining a space between the two walls at a certain horizontal distance L, thereby forming a gob-side retained passageway; upon mining a lower section coal mining workface (2), providing the gob-side retained passageway in a track passageway (5) of the lower section coal mining workface (2), and at the same time removing a flexible film bag (9) from the surface of the support wall (11) adjacent to a passageway of an upper section gob-side retained passageway located behind the workface; after recovery of the lower section coal mining workface (2) is completed, injecting carbon dioxide into the ventilation pipe (10) within the support wall (11) adjacent to a passageway and the pressure buffer wall (13) of the upper section coal mining workface (1) to promote a carbonization reaction, crumbling and decomposition of the wall, thus realizing mining entirely without the use of coal pillars. The method facilitates complete maintenance of the gob-side retained passageway, realizes a gob-side retained passageway at a large seam height workface of a thick coal layer, notably increases coal recovery ratio, and eliminates stress concentration above and below the walls.