Roof Movement and Failure Behavior When Mining Extra-Thick Coal Seams Using Upward Slicing Longwall-Roadway Cemented Backfill Technology

Figure 6

Deflection curves of the roof in the first mining cycle of the first slice. (a) 1-1-1∼1-1-4 mining step and (b) 1-1-5∼1-1-7 mining step.

(a)

(b)