Stability Analysis and Fracture Patterns of Hard Main Roof in Longwall Top Coal Caving with Large Mining Height

Figure 6

Fracture pattern evolution of roof with the advance of LTCC face. (a) 112 m, (b) 192 m, (c) 224 m, (d) 272 m, (e) 336 m, (f) 400 m, and (g) 432 m.

(a)

(b)

(c)

(d)

(e)

(f)

(g)