Abstract:

To address the issues induced by full-thickness mining in soft and extra-thick coal seams—including instability of the deep beam structure of the roof, excessive deformation of the roof and sidewalls in mining roadways, slow roadway drivage caused by uncoordinated excavation and support operations that constrain backfilling efficiency, as well as low backfill roof-contact ratio and severe slurry leakage—and to achieve efficient and safe mining of soft and extra-thick coal seams, a layered staggered collaborative mining-and-backfilling technology is proposed. The coal seam is divided into upper and lower layers, with branch roadways arranged at a staggered spacing of 50% of the roadway width. This is complemented by a high-efficiency intelligent mining-and-backfilling equipment system consisting of a high-efficiency rapid-cutting horizontal-axis integrated roadheader-and-bolterexcavation, a straddle-type full-face support trolley, a self-moving flexible belt conveyor, and an intelligent one-key automated backfilling control system. Application in the No.16 soft and extra-thick coal seam of Laoshidan Coal Mine demonstrates that this system can liberate 20 million tonnes of coal resources trapped under surface buildings, increase the daily drivage footage of branch roadways to 40 m, achieve an annual output of 443 500 t, simultaneously realize underground gangue conversion and emission reduction, extend the mine service life by 15 years, and provide a complete solution for the efficient mining of soft and extra-thick coal seams and resource-depleted mines.

Key words: Laoshidan coal mine, soft and extra-thick coal seams, mining and backfilling, layered dislocation, lollaborative mining