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

Figure 3

The movement state of the roof during coal seam mining in the physical model.

(a) Initial equilibrium state

(b) Mining distance: 35 cm

(c) Mining distance: 40 cm

(d) Mining distance: 55 cm

(e) Mining distance: 70 cm

(f) Mining distance: 90 cm

(g) Mining distance: 105 cm

(h) Mining distance: 110 cm