Breaking and Instability Movement Characteristics of High-Position Double-Layer Hard Thick Strata due to Longwall Mining

Figure 4

Variation of plastic zone during the mining process. (a) 70 m. (b) 160 m. (c) 190 m. (d) 220 m. (e) 250 m. (f) 370 m. (g) 550 m.

(a)

(b)

(c)

(d)

(e)

(f)

(g)