Comprehensive Treatment Technology of Complex Empty Roadway in Large Height and Ultra-long Mining Face

Aiming at the complex technical problems of large mining height and super-long working face in Chengzhuang Mine, such as large number of gobs, large section size and wide influence range, a series of comprehensive treatment measures for complex gobs are proposed. Full filling method is adopted in small section gob, backfilling pillar support method is adopted in super large section gob, and reasonable strength and yielding structure of backfilling pillar are designed through theoretical analysis; coal pre-grouting method is adopted in stress concentration area of coal body, and working face inclination adjustment is adopted when working face passes through gob. The supplementary measures of chemical grouting on coal wall ensure the stability of coal wall and roof, reduce floor heave and deformation of both sides of roadway, and ensure the smooth passage of the working face through the roadway. After comprehensive treatment, the working face passes through all the roadways safely and smoothly, and there is no obvious phenomenon of coal wall and side wall in the working face. The roof and two sides of the roadway do not have obvious deformation, and good engineering application effect has been achieved.