Investigation on the Movement and Fracture Characteristics of an Extra-Thick Hard Roof during Longwall Panel Extraction in the Yima Mining Area, China

Figure 10

Velocity vector variation of the roof during the advancement of the mining face.

(a) Mining distance: 20 cm

(b) Mining distance: 40 cm

(c) Mining distance: 55 cm

(d) Mining distance: 70 cm

(e) Mining distance: 90 cm

(f) Mining distance: 110 cm