Abstract: Restricted by geological conditions and existing roadways layout of some mining area under buildings, railways, and water bodies, to guarantee the controlling effect of solid backfill mining to strata movement and ground deformation, the article proposed solid backfill mining technology on condition of two entries pre-excavation, analyzed its principle and the technical difficulties, established advancing solid backfill mining system on condition of two entries pre-excavation, optimized key equipment structure for backfill mining and corresponding layout, and designed an integrated technique and a comprehensive system based on the technical features of both solid backfill mining and gob-side entry. On-site practice shows that the filling ratio of 90.6% is achieved, the cross section of the retained entries account for more than 90% of the original one, and the maximal sinking value of the ground is 125 mm, which prove this technology can effectively control the strata movement and ground deformation. This integrated technology shows a great potential for excavating the coal resource under similar conditions.

Key words: two entries pre-excavation, advancing mining, solid backfill mining, gob-side entry retaining, filling ratio