Abstract
For efficient, economical and environmentally disposing the waste rock underground, based on principles of waste direct
backfilling in fully mechanized coal mining, this paper carries out a field test in 6304-1 working face of Jining No.3 Coal Mine.
We first design a waste rock direct underground processing system, including screening-crushing system, transportation system,
transfer system, stope backfilling system and coal mining system. Then optimize the waste backfilling and coal mining
technology, update the waste backfilling process with “start backfilling from backfill scraper conveyor’s head to tail, gradually
uplift tamping arm, gradually compact backfill materials, move backfill scraper conveyor forward when the tamping arm can’t
extend out and last fill roof gap by up material pushed by down material”. At last, imply this system and check strata movement
controlling effect by actual measuring the roof dynamic change law, which supported by the dense backfill body. The results
show that the test working face can cut 0.6 million tons of raw coal one year, and direct backfill 0.74 million tons of waste rocks
at the same time, and the maximum subsidence of immediate roof observed in situ is 340mm, the maximum caving speed is
11.89 mm/d, the real compression ratio of backfill body is 90.3%, the overlying strata movement of backfilled area is effectively
controlled by backfill body of waste rock.