Industrial Test of Concrete Packing for Gob-Side Entry Retained in Gently-Inclined Medium-Thickness Coal Seam

In order to carry out gob-side entry retaining for a fully-mechanized coal faces in a gently-inclined medium-thickness coal seam to improve coal recovery, an integrated supporting scheme was proposed. In this scheme pumping concrete is used as filling material, single hydraulic props as temporary supporting on the both sides of concrete backfill and anchor cables as reinforce supporting along goaf. Proportioning tests on filling concrete were conducted in the lab, supporting parameters were determined based on the strata control theory, and an industrial test was carried through successfully in No.3117 fully-mechanized coal face in Jingang Coal Mine. The test result shows that roadside packing with ordinary concrete combining with single hydraulic props as temporary supporting can overcome the disadvantage of ordinary concrete in initial strength to effectively control roof strata.