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

Figure 12

Vertical stress distribution of the extra-thick 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